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Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2018 shares
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	Viomi Technology Co., Ltd
Entity Central Index Key	0001742770
Current Fiscal Year End Date	--12-31
Trading Symbol	VIOT
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Class A Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding	90,200,000
Class B Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding	117,600,000

CONSOLIDATED BALANCE SHEETS ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Current assets
Cash and cash equivalents	¥ 940,298	$ 136,761	¥ 279,952
Restricted cash	29,550	4,298	0
Short-term investments	168,993	24,579	0
Accounts receivable from third parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	111,718	16,249	4,348
Accounts receivable from a related party (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	260,984	37,959	249,548
Other receivables from related parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	112,320	16,336	57,608
Inventories	231,975	33,739	50,692
Prepaid expenses and other current assets	46,890	6,819	23,283
Total current assets	1,902,728	276,740	665,431
Non-current assets
Prepaid expenses and other non-current assets	3,636	529	0
Property, plant and equipment, net	11,301	1,644	3,086
Deferred tax assets	5,234	761	3,048
Intangible assets, net	169	25	0
Total non-current assets	20,340	2,959	6,134
Total assets	1,923,068	279,699	671,565
Current liabilities
Accounts and notes payable (including accounts and notes payable of the consolidated VIEs without recourse to the Group of RMB291,643 and RMB548,481 as of December 31, 2017 and 2018, respectively)	548,481	79,773	291,643
Advances from customers (including advances from customers of the consolidated VIEs without recourse to the Group of RMB27,015 and RMB86,312 as of December 31, 2017 and 2018, respectively)	86,312	12,554	27,015
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)	5,763	838	35,953
Accrued expenses and other liabilities (including accrued expenses and other liabilities of the consolidated VIEs without recourse to the Group of RMB60,953 and RMB179,712 as of December 31, 2017 and 2018, respectively)	200,930	29,225	61,424
Share-based compensation liabilities (including share-based compensation liabilities of the consolidated VIEs without recourse to the Group of nil and nil as of December 31, 2017 and 2018, respectively)			4,738
Income tax payables (including income tax payables of the consolidated VIEs without recourse to the Group of RMB11,612 and RMB10,199 as of December 31, 2017 and 2018, respectively)	10,199	1,483	11,612
Total current liabilities	851,685	123,873	432,385
Non-current liabilities
Accrued expenses and other liabilities (including accrued expenses and other liabilities of the consolidated VIEs without recourse to the Group of RMB460 and RMB518 as of December 31, 2017 and 2018, respectively)	518	75	460
Total non-current liabilities	518	75	460
Total liabilities	852,203	123,948	432,845
Mezzanine equity
Total mezzanine equity			407,928
Shareholders’ (deficit) equity
Additional paid-in capital	1,193,174	173,540	9,679
Accumulated deficit	(95,527)	(13,894)	(160,885)
Accumulated other comprehensive loss	(29,786)	(4,332)	(18,004)
Total Viomi Technology Co., Ltd (the "Company")'s shareholders’ (deficit) equity	1,067,873	155,316	(169,208)
Non-controlling interests	2,992	435
Total shareholders’ (deficit) equity	1,070,865	155,751	(169,208)
Total liabilities, mezzanine equity and shareholders’ (deficit) equity	1,923,068	279,699	671,565
Class B redeemable convertible ordinary shares
Mezzanine equity
Total mezzanine equity			256,883
Series A redeemable convertible preferred shares
Mezzanine equity
Total mezzanine equity			151,045
Class A Ordinary Shares
Shareholders’ (deficit) equity
Ordinary shares, value			2
Class A Ordinary Shares \| Post-IPO
Shareholders’ (deficit) equity
Ordinary shares, value	5	1	0
Class B Ordinary Shares \| Post-IPO
Shareholders’ (deficit) equity
Ordinary shares, value	¥ 7	$ 1	¥ 0

CONSOLIDATED BALANCE SHEETS (Parenthetical) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥) shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 CNY (¥) shares	Dec. 31, 2017 $ / shares
Accounts and notes payable current	¥ 548,481	$ 79,773	¥ 291,643
Advances from customers	86,312	12,554	27,015
Amounts due to related parties	5,763	838	35,953
Accrued expenses and other liabilities current	200,930	29,225	61,424
Share-based compensation liabilities \| ¥			4,738
Income tax payables	10,199	1,483	11,612
Accrued expenses and other liabilities non current	518	$ 75	460
VIEs
Accounts Receivable, Net, Current \| ¥
Accounts and notes payable current \| ¥	548,481		291,643
Advances from customers \| ¥	86,312		27,015
Amounts due to related parties \| ¥	5,763		35,953
Accrued expenses and other liabilities current \| ¥	179,712		60,953
Income tax payables \| ¥	10,199		11,612
Accrued expenses and other liabilities non current \| ¥	518		460
Related Party
Accounts Receivable, Net, Current \| ¥	0		0
Accounts and Other Receivables, Net, Current \| ¥	0		0
Third Party
Accounts Receivable, Net, Current \| ¥	¥ 0		¥ 0
Class B Ordinary Shares
Mezzanine equity, par value \| $ / shares		$ 0.00001		$ 0.00001
Mezzanine equity, shares authorized	0	0	1,352,727,280
Mezzanine equity, shares issued	0	0	135,272,728
Mezzanine equity, shares outstanding	0	0	84,545,455
Mezzanine equity, liquidation value \| ¥	¥ 0		¥ 9,306
Series A Preferred Shares
Mezzanine equity, par value \| $ / shares		$ 0.00001		0.00001
Mezzanine equity, shares authorized	0	0	181,818,180
Mezzanine equity, shares issued	0	0	18,181,818
Mezzanine equity, shares outstanding	0	0	18,181,818
Mezzanine equity, liquidation value \| ¥	¥ 0		¥ 183,453
Class A Ordinary Shares
Common stock, par value per share \| $ / shares		$ 0.00001
Common stock, shares issued			33,818,182
Common stock, shares outstanding	0	0	25,363,636
Class A Ordinary Shares \| Before Share Split Event After Retroactive Adjustment [Member]
Common stock, par value per share \| $ / shares				$ 0.00001
Common stock, shares authorized			3,465,454,540
Class A Ordinary Shares \| Post-IPO
Common stock, par value per share \| $ / shares		$ 0.00001
Common stock, shares authorized	4,800,000,000	4,800,000,000
Common stock, shares issued	90,200,000	90,200,000
Common stock, shares outstanding	90,200,000	90,200,000
Class B Ordinary Shares \| Post-IPO
Common stock, par value per share \| $ / shares		$ 0.00001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	117,600,000	117,600,000
Common stock, shares outstanding	117,600,000	117,600,000

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥) ¥ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares	Dec. 31, 2016 CNY (¥) ¥ / shares shares
Net revenues:
A related party	¥ 1,311,852	$ 190,801	¥ 739,464	¥ 299,827
Third parties	1,249,377	181,714	133,755	12,747
Total net revenues	2,561,229	372,515	873,219	312,574
Cost of revenues
Purchase from a related party	(14,733)	(2,143)	(1,296)	(1,321)
Purchase from third parties	(1,828,699)	(265,973)	(596,740)	(231,223)
Total cost of revenues	(1,843,432)	(268,116)	(598,036)	(232,544)
Gross profit	717,797	104,399	275,183	80,030
Operating expenses:
Research and development expenses	(124,230)	(18,069)	(60,749)	(29,926)
Selling and marketing expenses (including RMB166, RMB3,327 and RMB24,598 with related parties for the years ended December 31, 2016, 2017 and 2018, respectively)	(379,554)	(55,204)	(95,296)	(20,929)
General and administrative expenses	(135,532)	(19,712)	(15,818)	(14,386)
Total operating expenses	(639,316)	(92,985)	(171,863)	(65,241)
Other (expenses) income	1,829	266	2,236	(481)
Income from operations	80,310	11,680	105,556	14,308
Interest (expenses) income and short-term investment income (including net interest expense of RMB1,489, RMB1,271 and RMB333 with related parties for the years ended December 31, 2016, 2017 and 2018, respectively)	8,846	1,287	2,402	(296)
Other non-operating income	255	37
Income before income tax benefits (expenses)	89,411	13,004	107,958	14,012
Income tax benefits (expenses)	(24,061)	(3,500)	(14,718)	2,247
Net income	65,350	9,504	93,240	16,259
Less: Net loss attributable to the non-controlling interest shareholder	(8)	(1)
Net income attributable to the Company	65,358	9,505	93,240	16,259
Net (loss) income attributable to ordinary shareholders of the Company	50,544	7,350	8,033	(3,453)
Net income attributable to the Company	65,358	9,505	93,240	16,259
Foreign currency translation adjustment	(11,782)	(1,714)	19,102	(23,080)
Total comprehensive (loss) income attributable to the Company	¥ 53,576	$ 7,791	¥ 112,342	¥ (6,821)
Net (loss) income per ADS*
-Basic \| (per share)	¥ 0.70	$ 0.10	¥ 0.39	¥ (0.28)
-Diluted \| (per share)	¥ 0.64	$ 0.09	¥ 0.31	¥ (0.28)
Weighted average number of ADS used in calculating net income per ADS
-Basic	71,771,033	71,771,033	20,684,681	12,230,136
-Diluted	79,590,780	79,590,780	25,579,806	12,230,136
Series A Preferred Shares
Operating expenses:
Accretion of Series A Preferred Shares	¥ (6,563)	$ (955)	¥ (8,834)	¥ (8,221)
Cumulative dividend	(7,631)	(1,110)	(10,803)	(10,628)
Undistributed earnings allocated \| ¥			(7,061)
Class B Ordinary Shares
Operating expenses:
Cumulative dividend	¥ (620)	$ (90)	(877)	¥ (863)
Undistributed earnings allocated \| ¥			(52,533)
Unvested Class A Ordinary Shares
Operating expenses:
Undistributed earnings allocated \| ¥			¥ (5,099)
American Depositary Shares
Net (loss) income per ADS*
-Basic \| (per share)	¥ 2.10	$ 0.31	¥ 1.17	¥ (0.84)
-Diluted \| (per share)	¥ 1.92	$ 0.28	¥ 0.93	¥ (0.84)
Weighted average number of ADS used in calculating net income per ADS
-Basic	23,923,678	23,923,678	6,894,894	4,076,712
-Diluted	26,530,260	26,530,260	8,526,602	4,076,712

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Parenthetical) (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Selling and marketing expenses from related party	¥ 24,598		¥ 3,327	¥ 166
Interest expense from related party	333		1,271	1,489
Share-based compensation expense	116,611		5,821	10,578
General and Administrative Expenses
Share-based compensation expense	93,718	$ 13,631	3,303	6,863
Research and Development Expenses
Share-based compensation expense	14,476	2,105	1,903	3,464
Selling and Marketing Expenses
Share-based compensation expense	¥ 8,417	$ 1,224	¥ 615	¥ 251

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' (DEFICIT) EQUITY ¥ in Thousands, $ in Thousands	CNY (¥)	USD ($)	Founder CNY (¥)	Conversion of Series A Redeemable Convertible Preferred Shares into Post-IPO Class A Ordinary Shares CNY (¥)	Conversion of Class B Redeemable Convertible Ordinary Shares into Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares CNY (¥)	2015 Share Incentive Plan CNY (¥)	2015 and 2018 Share Incentive Plan CNY (¥)	Class A Ordinary Shares shares	Post-IPO Class A Ordinary Shares shares	Post-IPO Class B Ordinary Shares shares	Common Stock Class A Ordinary Shares CNY (¥) shares	Common Stock Class A Ordinary Shares Founder shares	Common Stock Class A Ordinary Shares Conversion of common class a ordinary shares into post IPO class B ordinary shares CNY (¥) shares	Common Stock Post-IPO Class A Ordinary Shares CNY (¥) shares	Common Stock Post-IPO Class A Ordinary Shares Conversion of Series A Redeemable Convertible Preferred Shares into Post-IPO Class A Ordinary Shares CNY (¥) shares	Common Stock Post-IPO Class A Ordinary Shares Conversion of Class B Redeemable Convertible Ordinary Shares into Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares CNY (¥) shares	Common Stock Post-IPO Class A Ordinary Shares Conversion of common class a ordinary shares into post IPO class B ordinary shares shares	Common Stock Post-IPO Class B Ordinary Shares CNY (¥) shares	Common Stock Post-IPO Class B Ordinary Shares Conversion of Class B Redeemable Convertible Ordinary Shares into Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares CNY (¥) shares	Common Stock Post-IPO Class B Ordinary Shares Conversion of common class a ordinary shares into post IPO class B ordinary shares CNY (¥) shares	Additional Paid-in Capital CNY (¥)	Additional Paid-in Capital Founder CNY (¥)	Additional Paid-in Capital Conversion of Series A Redeemable Convertible Preferred Shares into Post-IPO Class A Ordinary Shares CNY (¥)	Additional Paid-in Capital Conversion of Class B Redeemable Convertible Ordinary Shares into Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares CNY (¥)	Additional Paid-in Capital 2015 Share Incentive Plan CNY (¥)	Additional Paid-in Capital 2015 and 2018 Share Incentive Plan CNY (¥)	Accumulated Deficit CNY (¥)	Accumulated Other Comprehensive Loss CNY (¥)	Total the Company's shareholders' Deficit CNY (¥)	Total the Company's shareholders' Deficit Founder CNY (¥)	Total the Company's shareholders' Deficit Conversion of Series A Redeemable Convertible Preferred Shares into Post-IPO Class A Ordinary Shares CNY (¥)	Total the Company's shareholders' Deficit Conversion of Class B Redeemable Convertible Ordinary Shares into Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares CNY (¥)	Total the Company's shareholders' Deficit 2015 Share Incentive Plan CNY (¥)	Total the Company's shareholders' Deficit 2015 and 2018 Share Incentive Plan CNY (¥)	Non-Controlling Interest CNY (¥)
Balances at Dec. 31, 2015	¥ (274,888)																				¥ 3,272						¥ (264,134)	¥ (14,026)	¥ (274,888)
Balances (in shares) at Dec. 31, 2015 \| shares											8,454,544
Vesting of restricted Class A ordinary shares	678										¥ 1										677								678
Vesting of restricted Class A ordinary shares (in shares) \| shares											8,454,546
Net income (loss)	16,259																										16,259		16,259
Share-based compensation related to Restricted Shares	6,144																				6,144								6,144
Share-based compensation related to Share Incentive Plan						¥ 4,168																			¥ 4,168								¥ 4,168
Accretion of Series A Preferred Shares	(8,221)																				(8,221)								(8,221)
Foreign currency translation adjustment	(23,080)																											(23,080)	(23,080)
Balances at Dec. 31, 2016	(278,940)										¥ 1										6,040						(247,875)	(37,106)	(278,940)
Balances (in shares) at Dec. 31, 2016 \| shares											16,909,090
Vesting of restricted Class A ordinary shares	689										¥ 1										688								689
Vesting of restricted Class A ordinary shares (in shares) \| shares											8,454,546
Net income (loss)	93,240																										93,240		93,240
Share-based compensation related to Restricted Shares	2,718																				2,718								2,718
Share-based compensation related to Share Incentive Plan						¥ 2,817																			¥ 2,817								¥ 2,817
Statutory reserve																					6,250						(6,250)
Accretion of Series A Preferred Shares	(8,834)																				(8,834)								(8,834)
Foreign currency translation adjustment	19,102																											19,102	19,102
Balances at Dec. 31, 2017	(169,208)										¥ 2										9,679						(160,885)	(18,004)	(169,208)
Balances (in shares) at Dec. 31, 2017 \| shares								25,363,636			25,363,636
Surrender and cancellation of Class A ordinary shares	457										¥ (1)										458								457
Surrender and cancellation of Class A ordinary shares (in Shares) \| shares											(11,754,546)
Vesting of restricted Class A ordinary shares	188																				188								188
Vesting of restricted Class A ordinary shares (in shares) \| shares											2,536,364
Net income (loss)	65,350	$ 9,504																									65,358		65,358						¥ (8)
Share-based compensation related to Restricted Shares	840																				840								840
Share-based compensation related to Share Incentive Plan							¥ 25,391																			¥ 25,391								¥ 25,391
Share-based compensation related to the share awards			¥ 90,168																			¥ 90,168								¥ 90,168
Share-based compensation related to the share awards (in shares) \| shares												4,000,000
Accretion of Series A Preferred Shares	(6,563)																				(6,563)								(6,563)
Issuance of ordinary shares upon the completion of the Initial Public Offering (the "IPO")	633,508													¥ 2							633,506								633,508
Issuance of ordinary shares post Initial Public Offering, in shares \| shares														34,200,000
Securities converted into Ordinary Shares upon the completion of the Initial Public Offering				¥ 165,095	¥ 274,421								¥ (1)		¥ 1	¥ 2			¥ 6	¥ 1			¥ 165,094	¥ 274,413							¥ 165,095	¥ 274,421
Securities have been converted into Ordinary Shares upon the completion of the Initial Public Offering (in shares) \| shares													(20,145,454)		18,181,818	33,818,182	4,000,000		101,454,546	16,145,454
Capital injection in a subsidiary from non controlling interest shareholder	3,000																																		3,000
Foreign currency translation adjustment	(11,782)	(1,714)																										(11,782)	(11,782)
Balances at Dec. 31, 2018	¥ 1,070,865	$ 155,751												¥ 5				¥ 7			¥ 1,193,174						¥ (95,527)	¥ (29,786)	¥ 1,067,873						¥ 2,992
Balances (in shares) at Dec. 31, 2018 \| shares								0	90,200,000	117,600,000				90,200,000				117,600,000

CONSOLIDATED STATEMENTS OF CASH FLOWS ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Cash flows from operating activities
Net income (loss)	¥ 65,350	$ 9,504	¥ 93,240	¥ 16,259
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,270	330	1,680	1,222
Inventory write-down	1,059	154	81	1,658
Share-based compensation	116,611	16,960	5,821	10,578
Deferred income tax benefits	(2,186)	(318)	(801)	(2,247)
Investment loss	364	53
Changes in operating assets and liabilities:
Accounts receivable from third parties	(107,370)	(15,616)	(4,348)
Accounts receivable from a related party	(11,436)	(1,663)	(204,527)	(33,084)
Inventories	(182,342)	(26,521)	(26,577)	(3,267)
Prepaid expenses and other current assets	(23,607)	(3,433)	(8,745)	(7,408)
Other receivables from related parties	(87,384)	(12,709)	(25,771)	847
Amounts due to related parties	4,005	583	1,179	(66)
Accounts and notes payable	256,838	37,356	218,614	12,111
Advances from customers	59,297	8,624	19,312	7,702
Income tax payables	(1,413)	(206)	11,612
Accrued expenses and other liabilities	132,213	19,230	43,136	11,194
Net cash provided by operating activities	222,269	32,328	123,906	15,499
Cash flows from investing activities
Cash received from loan repayment from a related party	31,441	4,573
Purchase of equipment	(13,505)	(1,964)	(1,234)	(1,609)
Purchase of non-current assets	(216)	(31)
Purchase of intangible assets	(184)	(27)
Purchase of short-term investments	(238,714)	(34,720)
Maturity of a short-term investment	69,357	10,088
Net cash used in investing activities	(151,821)	(22,081)	(1,234)	(1,609)
Cash flows from financing activities
Repayment of debt to a related party	(31,900)	(4,640)
Cash received from shareholders	2,705	393	2,671
Net proceeds from issuance of ordinary shares upon IPO	636,170	92,527
Capital injection in a subsidiary from non-controlling shareholder	3,000	436
Cash paid to a related party	(5,000)	(727)
Proceeds received from issuance of Series A Preferred Shares	0	0		12,999
Net cash provided by financing activities	604,975	87,989	2,671	12,999
Effect of exchange rate changes on cash and cash equivalents	14,473	2,105	(2,321)	2,913
Net increase in cash and cash equivalents and restricted cash	689,896	100,341	123,022	29,802
Cash and cash equivalents at the beginning of the year	279,952	40,718	156,930	127,128
Cash and cash equivalents and restricted cash at the end of the year	969,848	141,059	279,952	156,930
Cash and cash equivalents at the end of the year	940,298	136,761	279,952	156,930
Restricted cash at the end of the year	29,550	4,298	0
Supplemental disclosures of cash flow information:
Cash paid for income tax	(27,660)	(4,023)	(3,907)
Cash paid for interest expense	(768)	(112)	(1,785)	(1,790)
Acquisition of equipment in form of other payable	¥ 430	$ 63	¥ 54	¥ 35

Organization and Principal Activities

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Principal Activities

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES

Viomi Technology Co., Ltd (the “Company”) is a holding company incorporated under the Laws of the Cayman Islands in January 2015. The Company, through its consolidated subsidiaries and variable interest entities (“VIEs”) (collectively referred to as the “Group”) is primarily engaged in the operation of developing and selling Internet-of-things-enabled (“IoT-enabled”) smart home products in the People’s Republic of China (“the PRC”).

(a)	History and Reorganization

The Group commenced its operations in May 2014 through Foshan Yunmi Electric Appliances Technology Co., Ltd. (“Foshan Viomi”), a PRC company established by Mr. Chen Xiaoping (“Mr. Chen” or the “Founder”), and Tianjin Jinxing Investment Co., Ltd. (“Tianjin Jinxing”), a subsidiary of Xiaomi Corporation (“Xiaomi”), who is an investor of the Company. Mr. Chen and Tianjin Jinxing invested RMB7,500 and RMB5,000 to establish Foshan Viomi and held 60% and 40% initial equity interests, respectively. Included in the RMB7,500 invested by Mr. Chen, RMB2,500 was invested by certain key management founders and held by Mr. Chen on their behalf (The key management founders, together with Mr. Chen are referred to “the Founders”). The Group has undertaken its reorganization (“Reorganization”) as detailed below.

In January 2015, the Company was incorporated in the Cayman Islands, Viomi HK Technology Co., Limited (“Viomi HK”) was incorporated in Hong Kong as a wholly owned subsidiary of the Company, Beijing Yunmi Technology Co., Ltd. (“Beijing Viomi”) was set up as a domestic company. In May 2015, Lequan Technology Beijing Co., Ltd (“Lequan”) was incorporated as a wholly owned subsidiary of Viomi HK in the PRC.

In July 2015, the Company issued 33,818,182 class A ordinary shares to exchange the interest of RMB2,500 in Foshan Viomi held by Mr. Chen on behalf of key management founders, 67,636,364 Class B Ordinary Shares to exchange the interest of RMB5,000 in Foshan Viomi owned by Mr. Chen, and 67,636,364 Class B Ordinary Shares to Red Better Limited (“Red Better”), a subsidiary of Xiaomi, and Shunwei Talent Limited (“Shunwei”), to exchange the interest of RMB5,000 held by Tianjin Jinxing. Concurrently, the Company obtained control over Foshan Viomi and Beijing Viomi through Lequan by entering into a series of contractual arrangements with Foshan Viomi, Beijing Viomi and their shareholders as detailed in note 1(c). As a result, Foshan Viomi and Beijing Viomi became the consolidated VIEs of the Group. The Reorganization lacks substance and should be treated as a non-substantive merger with no change in the basis of assets and liabilities of Foshan Viomi.

In addition, the Company issued 18,181,818 Series A Preferred Shares at the issue price of US$1.1 per share to a group of investors for considerations of US$20,000, including conversion of the outstanding bridge loans of US$5,250, which was provided by the same investors during January 2015 to July 2015. The remaining consideration was fully received in cash.

In June 2018, the Board of Directors and the shareholders approved a transfer and surrender of shares plan, pursuant to which, Mr. Chen, who holds 33,818,182 class A ordinary shares on behalf of certain key management founders through Viomi Limited, transferred 16,145,454 class A ordinary shares to key management founders and surrendered the remaining 17,672,728 class A ordinary shares to the Company.

Prior to the completion of the IPO, in accordance with written resolutions of all the shareholders of the Company on August 23, 2018, the Company effected a share split whereby each of the Company’s authorized and outstanding ordinary shares and preferred shares, par value of $0.0001 each, was divided into ten ordinary shares and preferred shares of the same series, par value US$0.00001 each, respectively. All shareholders surrendered 90% of their after-share-split outstanding shares back to the Company for cancellation. After the share split and the surrender of shares for cancellation, the number of the Company’s outstanding ordinary and preferred shares remained unchanged. As the number of outstanding shares remained unchanged, the share split does not have an impact to the basic and diluted net (loss) income per share for the years ended December 31, 2016 and 2017. The par value per ordinary share has been retroactively revised as if it had been adjusted in proportion to the share split.

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

As of December 31, 2018, details of the Company’s principal subsidiaries and VIEs were as follows:

	Place of incorporation	Date of incorporation	Percentage of beneficial ownership	Principal activities
Subsidiaries:
Viomi HK	Hong Kong	January 30, 2015	100%	Investment holding
Lequan	PRC	May 15, 2015	100%	Investment holding
VIEs:
Foshan Viomi	PRC	May 6, 2014	100%	Home appliance development and sales
Beijing Viomi	PRC	January 12, 2015	100%	No substantial business
Subsidiaries of Foshan Viomi:
Guangdong Lizi Technology Co., Ltd. (“Guangdong Lizi”)	PRC	July 26, 2018	VIE’s subsidiary	Home appliance development and sales

(b)	Initial Public Offering

On September 25, 2018, the Company completed its IPO on the NASDAQ Global Market in the United States of America. In this offering, 11,400,000 American Depositary Shares (“ADSs”), representing 34,200,000 Post-IPO Class A Ordinary Shares, were issued and sold to the public at a price of US$9.00 per ADS.

Following the resolution of the shareholders of the Company on August 23, 2018, the Company’s authorized share capital became US$50,000 divided into 5,000,000,000 shares comprising of the (i) 4,800,000,000 class A ordinary shares of a par value of US$0.00001 each (‘‘Post-IPO Class A Ordinary Shares’’), (ii) 150,000,000 class B ordinary shares of a par value of US$0.00001 each (‘‘Post-IPO Class B Ordinary Shares’’) and (iii) 50,000,000 shares of a par value of US$0.00001 each of such class or classes (however designated) as the board of directors may determine in accordance with post-offering amended and restated memorandum and articles of association. In respect of all matters subject to a shareholder vote, each Post-IPO Class A Ordinary Share is entitled to one vote, and each Post-IPO Class B Ordinary Share is entitled to ten (10) votes, voting together as one class. Each Post-IPO Class B Ordinary Share is convertible into one Post-IPO Class A ordinary share at any time by the holder thereof. Post-IPO Class A Ordinary Shares are not convertible into Post-IPO Class B Ordinary Shares under any circumstances. Upon any transfer of Post-IPO Class B Ordinary Shares by a holder to any person or entity other than holders of Post-IPO Class B Ordinary Shares or their affiliates, such Post-IPO Class B Ordinary Shares shall be automatically and immediately converted into the equivalent number of Post-IPO Class A Ordinary Shares.

Immediately prior to the completion of the IPO, 16,145,454 issued class A ordinary shares held by certain key management founders, 33,818,182 issued Class B Ordinary Shares held by Red Better, and 67,636,364 issued Class B Ordinary Shares held by Mr. Chen’s wholly-owned entity Viomi Limited was automatically converted by way of re-designation and re-classification into Post-IPO Class B Ordinary Shares on a one-for-one basis, and the rest of the outstanding class A ordinary shares, the rest of the outstanding Class B Ordinary Shares, and all outstanding Series A Preferred Shares was automatically converted by way of re-designation and re-classification into Post-IPO Class A Ordinary Shares on a one-for-one basis.

(c)	VIE Arrangements between the VIEs and the Company’s PRC subsidiary

The Company, through Lequan, entered into the following contractual arrangements with Foshan Viomi, Beijing Viomi and their shareholders that enable the Company through its PRC subsidiary to (1) have power to direct the activities that most significantly affects the economic performance of the VIEs, through the exercise of the shareholders’ rights under the shareholder voting proxy agreement as the shareholders’ meetings of the VIEs appoint the board of directors of the VIEs, and (2) receive the economic benefits of the VIEs that could be significant to the VIEs through the exclusive consultation and service agreement. Accordingly, Lequan is considered the primary beneficiary of the VIEs and has consolidated the VIEs’ financial results of operations, assets and liabilities in the Company’s consolidated financial statements. In making the conclusion that Lequan is the primary beneficiary of the VIEs, the Company believes Lequan’s rights under the terms of the option agreement provide it with a substantive kick-out right. As advised by the Company’s PRC legal counsel, the Company believes the terms of the option agreement are valid, binding and enforceable under PRC laws and regulations currently in effect. The Company also believes that the consideration which is the minimum amount permitted by the applicable PRC law to exercise the option does not represent a financial barrier or disincentive for Lequan to currently exercise its rights under the exclusive option agreement.

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

A simple majority vote of Lequan’s board of directors is required to pass a resolution to exercise Lequan’s rights under the option agreement, for which Mr. Chen’s, the CEO of the Company, consent is not required. Lequan’s rights under the option agreement give Lequan the power to control the shareholders of Foshan Viomi and Beijing Viomi. In addition, Lequan’s rights under the shareholder voting proxy agreement also reinforce Lequan’s abilities to direct the activities that most significantly impact the VIEs’ economic performance. The Company also believes that this ability to exercise control ensures that the VIEs will continue to execute consultation and service agreements and also ensures that consultation and service agreements will be executed and renewed indefinitely unless a written agreement is signed by all parties to terminate it or a mandatory termination is requested by PRC laws or regulations. Lequan has the rights to receive substantially all of the economic benefits from the VIEs.

Exclusive consulting and service agreement. In July 2015, Lequan entered into exclusive consultation and service agreements with Foshan Viomi and Beijing Viomi respectively to enable Lequan to receive substantially all of the economic benefits of the VIEs. Under the exclusive consultation and service agreements, Lequan has the exclusive right to provide or designate any entity affiliated with it to provide VIEs the technical and business support services, including information technology support, hardware management and updates, software development, maintenance and updates and other operating services. The exclusive consultation and service agreement could be indefinitely effective unless a written agreement is signed by all parties to terminate it or a mandatory termination is requested by PRC laws or regulations. The exclusive consultation and service agreement was effective in July 2015. The consultation and service agreement will remain effective until all equity interests and assets in Foshan Viomi and Beijing Viomi are sold to Lequan or the party designated by Lequan. Under this arrangement, Lequan has the sole discretion to receive an annual service fee at an amount up to 100% of the annual net income of Foshan Viomi and Beijing Viomi. In addition, Lequan is entitled to receive certain other technical service fees at the amount mutually agreed upon by Lequan and the respective VIE.

Equity pledge agreement. Pursuant to the equity pledge agreements in July 2015 among Foshan Viomi, Beijing Viomi, all of their shareholders and Lequan, all shareholders of Foshan Viomi and Beijing Viomi agreed to pledge their equity interests in Foshan Viomi or Beijing Viomi to Lequan to secure the performance of the VIEs’ obligations under the existing exclusive purchase option agreement, shareholder voting proxy agreement, exclusive consulting and service agreement and also the equity pledge agreement. The Pledge will remain binding until Foshan Viomi, Beijing Viomi and their shareholders discharge all their obligations under the contractual agreements.

Exclusive purchase option agreement. Pursuant to the exclusive option agreements entered into in July 2015 among Lequan, Foshan Viomi, Beijing Viomi and their shareholders, the shareholders of Foshan Viomi and Beijing Viomi are obligated to sell their equity interest to Lequan. Lequan has the exclusive and irrevocable right to purchase, or cause the shareholders of Foshan Viomi and Beijing Viomi to sell to the party designated by Lequan, in Lequan’s sole discretion, all of the shareholders’ equity interests or any assets in Foshan Viomi and Beijing Viomi when and to the extent that applicable PRC law permits Lequan to own such equity interests and assets in Foshan Viomi and Beijing Viomi. The price to be paid by Lequan or any party designated by Lequan will be the minimum amount of consideration permitted by applicable PRC law at the time when such transaction occurs. All of the shareholders promised and agreed that they will refund the consideration once received to Lequan or any party designated by Lequan within 10 working days. Also, the shareholders of Foshan Viomi and Beijing Viomi should try their best to help Foshan Viomi and Beijing Viomi develop well and are prohibited from transferring, pledging, intentionally terminating significant contracts or otherwise disposing of any significant assets in Foshan Viomi and Beijing Viomi without Lequan’s prior written consent. The exclusive option agreement will remain effective until all equity interests and assets in Foshan Viomi and Beijing Viomi are sold to Lequan or the party designated by Lequan.

Shareholder voting proxy agreement. On July 21, 2015, all of the shareholders of Foshan Viomi and Beijing Viomi have executed a shareholder voting proxy agreement with Lequan, Foshan Viomi and Beijing Viomi, whereby all of the shareholders irrevocably appoint and constitute the person designated by Lequan as their attorney-in-fact to exercise on their behalf any and all rights that the shareholders have in respect of their equity interests in Foshan Viomi and Beijing Viomi. The shareholder voting proxy agreement will be indefinitely effective unless all parties decide to terminate it by written agreement.

In September 2018, Foshan Viomi reduced its registered capital and changed its shareholders from Mr. Chen and Tianjin Jinxing to Mr. Chen alone. Concurrently, the Group entered into a series of contractual arrangements in substantially the same forms with Foshan Viomi and Mr. Chen.

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

Management therefore concluded that the Company, through its PRC subsidiary and the above contractual arrangements, has the power to direct the activities that most significantly impact the VIEs' economic performance, bears the risks of and enjoys the rewards normally associated with ownership of the VIEs, and therefore the Company is the ultimate primary beneficiary of these VIEs. Consequently, the financial results of the VIEs were included in the Group's consolidated financial statements.

Risks in relation to VIE structure

The Company believes that the contractual arrangements between Lequan and its VIEs and their respective shareholders are in compliance with PRC laws and regulations and are legally enforceable. However, uncertainties in the PRC legal system could limit Lequan’s ability to enforce the contractual arrangements. If the legal structure and contractual arrangements were found to be in violation of PRC laws and regulations, the PRC government could:

•

revoke the business and operating licenses of the Company’s PRC subsidiary and VIEs;

•

discontinue or restrict the operations of any related-party transactions between the Company’s PRC subsidiary and VIEs;

•

limit the Group’s business expansion in China by way of entering into contractual arrangements;

•

impose fines or other requirements with which the Company’s PRC subsidiary and VIEs may not be able to comply;

•

impose additional conditions or requirements with which the Group may not be able to comply;

•

take other regulatory or enforcement actions against the Group that could be harmful to the Group’s business or

•

require the Company or the Company’s PRC subsidiary or VIEs to restructure the relevant ownership structure or operations.

The Company’s ability to conduct its business may be negatively affected if the PRC government were to carry out any of the aforementioned actions. As a result, the Company may not be able to consolidate its VIEs in its consolidated financial statements as it may lose the ability to exert effective control over the VIEs and their respective shareholders and it may lose the ability to receive economic benefits from the VIEs. The Company, however, does not believe such actions would result in the liquidation or dissolution of the Company, its PRC subsidiary or VIEs.

Mr. Chen is the only shareholder of Foshan Viomi and the largest shareholder of Beijing Viomi, and Mr. Chen is also the largest beneficiary owner of the Company. The interests of Mr. Chen as the largest beneficiary owner of the VIEs may differ from the interests of the Company as a whole, since Mr. Chen is only one of the beneficiary shareholders of the Company. The Company cannot assert that when conflicts of interest arise, Mr. Chen will act in the best interests of the Company or that conflicts of interests will be resolved in the Company’s favor. Currently, the Company does not have existing arrangements to address potential conflicts of interest Mr. Chen may encounter in his capacity as a beneficial owner and director of the VIEs, on the one hand, and as a beneficial owner and director of the Company, on the other hand. The Company relies on Mr. Chen, as a director and executive officer of the Company, to fulfill his fiduciary duties and abide by laws of the PRC and Cayman Islands and act in the best interest of the Company. If the Company cannot resolve any conflicts of interest or disputes between the Company and Mr. Chen, the Company would have to rely on legal proceedings, which could result in disruption of its business, and there is substantial uncertainty as to the outcome of any such legal proceedings.

In addition, the other shareholder of Beijing Viomi is also a beneficial owner of the Company and therefore have no current interest in seeking to act contrary to the contractual arrangements. However, to further protect the investors’ interest from any risk that the shareholders of the Foshan Viomi and Beijing Viomi may act contrary to the contractual arrangements, the Company, through Lequan, entered into a shareholder voting proxy agreement with all of the shareholders of Foshan Viomi and Beijing Viomi in July 2015. The shareholder voting proxy agreement with the shareholder of Foshan Viomi has been updated in September 2018 as Foshan Viomi reduced its registered capital and changed its shareholders from Mr. Chen and Tianjin Jinxing to Mr. Chen alone. Through the shareholder voting proxy agreement, all shareholders of Foshan Viomi and Beijing Viomi have entrusted the person designated by Lequan as its proxy to exercise their rights as the shareholders of Foshan Viomi and Beijing Viomi with respect to an aggregate of 100% of the equity interests in Foshan Viomi and Beijing Viomi.

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

In March 2019, the National People’s Congress enacted PRC Foreign Investment Law which would be effective starting from January 1, 2020. The Foreign Investment Law does not explicitly classify contractual arrangements as a form of foreign investment, but it contains a catch-all provision under the definition of “foreign investment”, which includes investments made by foreign investors through means stipulated in laws or administrative regulations or other methods prescribed by the State Council. Existing laws or administrative regulations remain unclear whether the contractual arrangements with variable interest entities will be deemed to be in violation of the market access requirements for foreign investment under the PRC laws and regulations. However, the possibility that such entities will be deemed as foreign invested enterprise and subject to relevant restrictions in the future shall not be excluded. If variable interest entities fall within the definition of foreign investment entities, the Group's ability to use the contractual arrangements with its VIE and the Group's ability to conduct business through the VIE could be severely limited.

The following table sets forth the assets, liabilities, results of operations and cash flows of the VIEs and its subsidiaries taken as a whole, which were included in the Group’s consolidated balance sheets and consolidated statements of comprehensive (loss) income. Transactions between the VIEs and its subsidiaries and the Group’s subsidiaries are eliminated in the financial information presented below:

	As of December 31,
	2017		2018
	RMB		RMB
Cash and cash equivalents		210,280		401,424
Restricted cash		—		29,550
Short-term investments		—		168,993
Accounts receivable from third parties (net of allowance of nil and nil as of December 31, 2017and 2018, respectively)		4,348		111,718
Accounts receivable from a related party (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)		249,548		260,984
Other receivable from related parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)		24,160		112,320
Inventories		50,692		231,975
Prepaid expenses and other current assets		22,986		46,499
Total current assets		562,014		1,363,463
Property, plant and equipment, net		3,086		11,301
Deferred tax assets		3,048		5,234
Intangible assets, net		—		169
Prepaid expenses and other non-current assets		—		3,636
Total non-current assets		6,134		20,340
Total assets		568,148		1,383,803
Accounts and notes payable		291,643		548,481
Advances from customers		27,015		86,312
Amounts due to related parties		35,953		5,763
Accrued expenses and other liabilities		60,953		179,712
Income tax payables		11,612		10,199
Total current liabilities		427,176		830,467
Accrued expenses and other liabilities		460		518
Total non-current liabilities		460		518
Total liabilities		427,636		830,985

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Revenue		312,523			873,083			2,561,229
Net income		16,295			92,159			70,232

Net cash provided by operating activities		13,146			123,182			209,690
Net cash used in investing activities		(1,609	)		(1,234	)		(183,262	)
Net cash provided by (used in) financing activities		12,999			—			(37,731	)

Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

SIGNIFICANT ACCOUNTING POLICIES

2.	SIGNIFICANT ACCOUNTING POLICIES

(a)	Basis of presentation

The consolidated financial statements of the Group have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) to reflect the financial position, results of operations and cash flows of the Group. Significant accounting policies followed by the Group in the preparation of the consolidated financial statements are summarized below.

(b)	Consolidation

The Group’s consolidated financial statements include the financial statements of the Company, its subsidiaries and VIEs for which the Company or its subsidiary is the primary beneficiary. All transactions and balances among the Company, its subsidiaries and VIEs have been eliminated upon consolidation.

A subsidiary is an entity in which the Company, directly or indirectly, controls more than one half of the voting powers; or has the power to appoint or remove the majority of the members of the board of directors; or to cast a majority of votes at the meeting of directors; or has the power to govern the financial and operating policies of the investee under a statute or agreement among the shareholders or equity holders.

A VIE is an entity in which the Company, or its subsidiary, through contractual agreements, bears the risks of, and enjoys the rewards normally associated with ownership of the entity, and therefore the Company or its subsidiary is the primary beneficiary of the entity. In determining whether the Company or its subsidiaries are the primary beneficiary, the Company considered whether it has the power to direct activities that are significant to the VIE’s economic performance, and also the Company’s obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. Lequan and ultimately the Company hold all the variable interests of the VIE and has been determined to be the primary beneficiary of the VIE.

(c)	Use of estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Significant accounting estimates reflected in the Group’s consolidated financial statements include sales returns, inventory valuation, product warranties, share-based compensation, fair value of preferred shares, and the valuation allowance for deferred tax assets and income tax. Actual results could differ from those estimates, and such differences may be material to the consolidated financial statements.

(d)	Foreign currency translation

The Group uses Renminbi (“RMB”) as its reporting currency. The functional currency of the Company and its subsidiary incorporated in Hong Kong is United States dollar (“US$”), while the functional currency of the Group’s entities in the PRC is RMB, which is their respective local currency. In the consolidated financial statements, the financial information of the Company and its subsidiary in Hong Kong, which use US$ as their functional currency, have been translated into RMB. Assets and liabilities are translated at the exchange rates on the balance sheet date, equity amounts are translated at historical exchange rates, and revenues, expenses, and incomes are translated using the average exchange rate for the period. Translation adjustments arising from these are reported as foreign currency translation adjustments and are shown as a component of other comprehensive (loss) income in the statement of comprehensive (loss) income.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

Foreign currency transactions denominated in currencies other than functional currency are translated into the functional currency using the exchange rates prevailing at the dates of the transactions. Monetary assets and liabilities denominated in foreign currencies at the balance sheet date are remeasured at the applicable rates of exchange in effect at that date. Foreign exchange gains and losses resulting from the settlement of such transactions and from remeasurement at year-end are recognized in foreign currency exchange (losses) gains, net in the consolidated statement of comprehensive (loss) income.

(e)	Convenience Translation

Translations of balances in the consolidated balance sheets, consolidated statements of comprehensive (loss) income and consolidated statements of cash flows from RMB into US$ as of and for the year ended December 31, 2018 are solely for the convenience of the reader and were calculated at the noon buying rate of US$1.00 = RMB6.8755 on December 31, 2018 as set forth in the H.10 statistical release of the U.S. Federal Reserve Board. No representation is made that the RMB amounts could have been, or could be, converted, realized or settled into US$ at that rate on December 31, 2018, or at any other rate.

(f)	Cash and cash equivalents

Cash includes currency on hand and deposits held by financial institutions that can be added to or withdrawn without limitation. Cash equivalents represent short-term and highly liquid investments placed with banks, and all highly liquid investments with original maturities of three months or less, which have both of the following characteristics:

Readily convertible to known amounts of cash throughout the maturity period;

ii)

So near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

(g)	Restricted cash

Cash that is restricted as to withdrawal or for use or pledged as security is reported separately on the face of the consolidated balance sheets. As the Company adopted Accounting Standards Update No. 2016-18 on January 1, 2018, restricted cash is included in the total cash and cash equivalents and restricted cash in the consolidated statements of cash flows when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The Group’s restricted cash mainly represents security deposits held in designated bank accounts for issuance of bank acceptance notes.

(h)	Short-term investments

For investments in financial instruments with a variable interest rate indexed to the performance of underlying assets, the Company elected the fair value method at the date of initial recognition and carried these investments subsequently at fair value. Changes in fair values are reflected in the consolidated statements of comprehensive (loss) income.

(i)	Accounts receivable

Accounts receivable are stated at the historical carrying amount net of allowance for doubtful accounts. The Group uses specific identification in providing for bad debts when facts and circumstances indicate that collection is doubtful and a loss is probable and estimable. If the financial conditions of its customers were to deteriorate, resulting in an impairment of their ability to make payments, additional allowance may be required.

The Company maintains an allowance for doubtful accounts which reflects its best estimate of amounts that potentially will not be collected. The Company determines the allowance for doubtful accounts on an individual basis taking into consideration various factors including but not limited to historical collection experience and credit-worthiness of the debtors as well as the age of the individual receivables balance. Additionally, the Company makes specific bad debt provisions based on any specific knowledge the Company has acquired that might indicate that an account is uncollectible. The facts and circumstances of each account may require the Company to use substantial judgment in assessing its collectability.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(j)	Inventories

The Group procures certain key raw materials and components from suppliers and send the materials to contract manufacturers for manufacture. The Group receives the finished goods from the contract manufacturers. Therefore, inventories of the Group consist of raw materials and finished goods. Inventories are stated at the lower of cost or net realizable value. Inventory costs include expenses that are directly or indirectly incurred in the purchase, and production of manufactured product for sale. Expenses include the cost of materials, consignment manufacturing cost and other direct costs. Cost is determined using the weighted average method. The Group assesses the valuation of inventory and periodically writes down the value for estimated excess and obsolete inventory based upon the product life-cycle. Write downs are recorded in cost of revenues in the consolidated statements of comprehensive (loss) income.

(k)	Property, plant and equipment, net

Property, plant and equipment are carried at cost less accumulated depreciation and impairment, if any. Depreciation is calculated on a straight-line basis over the following estimated useful lives and residual value. Residual rate is determined based on the economic value of the property and equipment at the end of the estimated useful lives as a percentage of the original cost.

	Estimated useful lives	Residual rate
Computers and equipment	2-3 years	0%-5%
Vehicle	4 years	5%

Expenditures for maintenance and repairs are expensed as incurred. The gain or loss on the disposal of property and equipment is the difference between the net sales proceeds and the carrying amount of the relevant assets and is recognized in the consolidated statements of comprehensive (loss) income.

(l)	Intangible assets

Intangible assets mainly consist of software. Identifiable intangible assets are carried at acquisition cost less accumulated amortization and impairment loss, if any. Finite-lived intangible assets are tested for impairment if impairment indicators arise. Amortization of finite-lived intangible assets is computed using the straight-line method over their estimated useful lives, which are as follows:

				Estimated useful lives
Software				5 years

(m)

Leases

Leases where substantially all the rewards and risks of ownership of assets remain with the lessor are accounted for as operating leases. Rental expense is recognized from the date of initial possession of the leased property on a straight-line basis over the term of the lease. Rental expenses incurred by the Group were RMB0.4 million, RMB1.1 million and RMB 3.9 million for the years ended December 31, 2016, 2017 and 2018, respectively.

The Group has no capital leases for any of the years presented.

(n)	Mezzanine equity

Mezzanine equity represents the Series A Preferred Shares and Class B Ordinary Shares issued by the Company. The Series A Preferred Shares and Class B Ordinary Shares are redeemable at the holders’ option any time after a certain date and were contingently redeemable upon the occurrence of certain liquidation events outside of the Company’s control. Therefore, the Group classifies the Series A Preferred Shares and Class B Ordinary Shares as mezzanine equity (Note 14).

In accordance with ASC 480-10, the mezzanine equity was initially measured based on its fair value at date of issue. Since the Series A Preferred Shares and Class B Ordinary Shares will be redeemable at the holder’s option 5 years from issuance if the Series A Preferred Shares and Class B Ordinary Shares are not converted, either voluntarily or automatically upon a qualified initial public offering (“Qualified IPO”), the Company accretes changes in the redemption value over the period from the date of issuance to the earliest redemption date of the instrument using the interest method.

Moreover, according to ASC-480-10-S99-2, where fair value at date of issue is less than the mandatory redemption amount, the carrying amount shall be increased by periodic accretions, using the interest method, so that the carrying amount will equal the mandatory redemption amount at the mandatory redemption date. Increase in carrying amount shall be recorded as charges against retained earnings or, in the absence of retained earnings, by charges against additional paid-in capital. As such, the accretion to the carrying amount of preferred share is recognized at minimum rate per annum of issuance price and plus the dividend declared.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(o)	Revenue recognition

In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”) and subsequently, the FASB issued several amendments which amend certain aspects of the guidance in ASC 2014-09 (ASU No. 2014-09 and the related amendments are collectively referred to as “ASC 606”). According to ASC 606, revenue is recognized when control of the promised good or service is transferred to the customers, in an amount that reflects the consideration the Group expects to be entitled to in exchange for those goods or services. The Group will enter into contracts that can include various combinations of products and services, which are generally capable of being distinct and accounted for as separate performance obligations. Revenue is recognized net of allowances for returns and any taxes collected from customers, which are subsequently remitted to governmental authorities. The Group adopted ASC 606 for all periods presented.

The Group’s revenue is primary derived from (i) IoT-enabled smart home products including smart water purification systems, smart kitchen products, and other smart products, (ii) consumable products complementary to the Group’s IoT smart home products, such as water purifier filters, (iii) others including the sales of other related household products as well as service fees from rendering of installation services. Refer to Note 11 to the consolidated financial statements for disaggregation of the Group’s revenue by type of product and service for the years ended December 31, 2016, 2017 and 2018.

1)	The Group conducts its business through various contractual arrangements, the following table disaggregates the Group’s revenue by type of contract for the years ended December 31, 2016, 2017 and 2018:

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Sales to Xiaomi		299,827		739,464		1,311,852
—Xiaomi-branded products		280,501		654,950		1,175,332
—Viomi-branded products		19,326		84,514		136,520
Sales to third-party customers		12,747		133,755		1,249,377
		312,574		873,219		2,561,229

Sales to Xiaomi’s affiliate Xiaomi Telecommunication Technology Co., Ltd. (“Xiaomi Telecommunication Technology”)

The Group generated a substantial portion of its revenues from sales of products to Xiaomi.

Under the cooperation agreement entered between the Group and Xiaomi Telecommunication Technology, the Group is responsible for design, research, development, production and delivery of designated products using the brand name of “Xiaomi” (“Xiaomi-branded products”). Xiaomi is responsible for commercial distributions and sales. The Group also sells some Viomi-branded products to Xiaomi.

Revenue from Xiaomi is recognized upon acceptance by this customer, which is considered at the time the control of the products is transferred to Xiaomi. Revenue from Xiaomi does not meet the criteria to be recognized over time since 1) even if the products use “Xiaomi” brand, it does not require significant rework to make them suitable to be sold to other customers, 2) under the cooperation agreement, the Group does not have the right of payment for the work performed to date.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

For a few types of products sold to this customer, the selling price is a fixed amount as agreed by both parties. For other types of products sold to this customer, the sales arrangement includes two installment payments. The first installment is priced to recover the costs incurred by the Group in developing, producing and shipping the products to this customer and is payable to the Group upon acceptance by the customer after delivery. The Group is also entitled to receive a potential second installment payment calculated as 50 percent of the future gross profits from commercial sales made by this customer. Accordingly, the Group determines the sales price as the fixed first installment payment plus the variable second installment payment to the extent that it is probable that revenue reversal will not occur when settling with the customer subsequently. The Group estimates the variable consideration using the expected value method. In assessing the variable second installment payment, the Group takes into consideration of the historical experience with the customer, selling price of the same or similar products as at the report date as well as the recent market trend. For the years ended December 31, 2016, 2017 and 2018, net revenues earned from second installment payment arrangement represented 15.3%, 15.0%and 9.0% of total revenue from Xiaomi, respectively.

Sales to third-party customers, including: sales to leading e-commerce platforms and offline experience stores; and sales to customers directly through the online platforms operated by Xiaomi, third parties and the Group.

- Sales to leading e-commerce platforms and offline experience stores

Pursuant to the contracts between the Group and the leading e-commerce platforms/offline experience stores (“e-commerce platforms and stores”), the e-commerce platforms and stores have legal title and physical possession of the products upon acceptance and they would bear the inventory risk of loss due to physical damage before the products are transferred and accepted by end customers. The e-commerce platforms and stores are responsible for delivering the products to end customers and can direct the use of the products and obtain the remaining benefits from the products by reselling the products. The e-commerce platforms and stores have flexibility in determining the retail sales price within relatively broad price range set by the Group. Based on these indicators, the Group determined the e-commerce platforms and stores (as opposed to the end customers) as its customers according to ASC 606-10-55-39. The Group recognizes revenue equal to the sales price to the e-commerce platforms and stores when control of the inventory is transferred.

- Sales to customers directly through the online platforms operated by Xiaomi, third parties and the Group

Under the cooperation agreements entered between the Group and online platforms, the platforms’ responsibilities are limited to offering an online marketplace, while the Group is primarily obligated in a sales transaction and takes inventory risk and has latitude in determining prices. The platforms charged the Group commission fees at pre-determined amounts or a fixed rate based on the sales amounts. Commission fees are recognized as selling expenses. The Group determined the end customers (as opposed to the platforms) as its customers and recognizes revenue equal to the sales price to the end customers when control of the inventory is transferred.

The Group provides installation service to end customers for a few Viomi-branded products without separate charge. The end customers have the right, not the obligation, to ask the Group to provide installation service. The installation service is considered being distinct and accounted for as a separate performance obligation as the products and installation services are not inputs into a combined item the end customer has contracted to receive. In addition, the Group does not provide any significant integration, modification, or customization services. It can fulfill its obligation to transfer each of the products or services separately. End customers do not always exercise their rights to ask for installation services as the installation may not be complicated and could be done by end customers themselves. Therefore, the Group expects to be entitled to a breakage amount in the contract liabilities related to installation services. The Group estimates the breakage portion based on historical customers’ requests and recognizes estimated breakage as revenue in proportion to the pattern of rights exercised by end customers. The assessment of estimated breakage would be updated on a quarterly basis. Changes in estimated breakage should be accounted for by adjusting contract liabilities to reflect the remaining rights expected to be exercised.

Judgment is required to determine standalone selling price for each distinct performance obligation. The Group allocates the arrangement consideration to the separate accounting of each distinct performance obligation based on their relative standalone selling price. The standalone selling price of the products is determined based on adjusted market assessment approach by estimating the price the customer is willing to pay for the product without installation service. For the standalone selling price of the installation services, the Group determines it by referring to actual costs charged by the third-party vendors, plus an estimated profit margin of 5% based on consideration of both company specific and relevant market factors.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

The Group recognizes revenue for the sales to third-party customers in accordance with the applicable revenue recognition method for each of the distinct performance obligation identified. Sales of products is recognized upon acceptance by customers after delivery. Installation service is recognized when the service is rendered.

2)	Sales returns and sales incentives

- Sales to leading e-commerce platforms

The Group’s sales to leading e-commerce platforms starting in 2018. As stipulated in the contracts, slow-moving goods are those unsold products after they are controlled by the e-commerce platforms for more than 30 days or 60 days or 90 days, depending on the different categories of products. The Group shall coordinate with the e-commerce platforms to sell the slowing-moving products to end customers through promotions within 30 days, otherwise, the e-commerce platforms can (i) return such slow-moving products, or (ii) sell on discount as determined by the e-commerce platforms. The Group shall bear all losses caused by such discounted sales. Based on the Group’s history of cooperation with the e-commerce platforms and the pattern that the e-commerce platforms dealt with slow-moving goods, the Group estimates that slow-moving goods will be returned to the Group instead of being sold through discounted sales by the e-commerce platforms. Under ASC 606, a right of return is not a separate performance obligation, but it affects the estimated transaction price for transferred goods. Revenue is only recognized for those products that are not expected to be returned. The estimate of expected returns should be determined in the same way as other variable consideration. Based on historical information and other relevant evidence, including the inventory turnover and aging in the e-commerce platforms, the Group assesses if it is probable there will be no significant reversal of cumulative revenue, and recognizes those sales as revenue. As of December 31, 2018, the expected return was insignificant to the Group. The Group would update its estimate at each period end.

Further, the Group might provide various consideration to the e-commerce platforms, such as gross margin guarantee, advertising and promotion fees, in the form of cash, or directly reducing amounts owed to the Group by the e-commerce platforms. The Group evaluates each type of incentives or fees to be paid in accordance with ASC 606. Considering that the Group either does not receive any service from the e-commerce platforms or cannot elect to engage another vendor to provide similar advertising services on a standalone basis, the Group reduces the transaction price for the sale of products by the amount of various consideration payable to the e-commerce platforms.

- Sales to Xiaomi and offline experience stores

Except for quality problem of the products, the Group does not allow sales return from Xiaomi and offline experience stores. The Group may provide sales rebates to the customers based on purchase volume, which are accounted for as variable consideration. The Group estimates these amounts based on the expected amount to be provided to the customers considering the contracted rebate rates and estimated sales volume based on historical experience, and reduce revenues recognized. For the years ended December 31, 2016, 2017 and 2018, the amount of sales rebate was insignificant.

- 7 days unconditional sales return

Under the consumer protection law, end customers have an unconditional right to return the products purchased through online platforms within 7 days. The Group bases its estimates of sales return on historical results. As of December 31, 2016, 2017 and 2018, the amount of expected sales return was insignificant. The Group may provide sales incentives in the forms of discounts to end customers through online platforms in a bundle transaction. Revenue, recognized on a net basis after such sales incentives, are allocated based on the relative standalone selling prices for respective products.

Warranty

The Group offers product warranty pursuant to standard product quality required by consumer protection law. The warranty period is calculated starting from the date when products are sold to the end customers. The Group has the obligation, at the customer’s sole discretion, to either repair or replace the defective product. The customers cannot separately purchase the warranty and the warranty doesn’t provide the customer with additional service other than assurance that the product will function as expected. Therefore, these warranties are accounted for in accordance with ASC 460 Guarantees. At the time revenue is recognized, an estimate of warranty expenses is recorded. The reserves established are regularly monitored based upon historical experience and any actual claims charged against the reserve. Warranty reserves are recorded as cost of revenues.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

4)	Value added taxes

Value added taxes (“VAT”) on sales is calculated at 17% on revenue from products before April 30, 2018 and 16% after May 1, 2018. The Group reports revenue net of VAT. Subsidiaries and VIEs that are VAT general tax payers are allowed to offset qualified VAT paid against their output VAT liabilities.

5)	Contract balances

Key customers, including Xiaomi and third-party customers, are entitled to a credit term. The expected length of time between the products being transferred to customers and when they pay for those products is short. There is no difference between the amount of promised consideration and the cash selling price of the promised products. Therefore, the Group concludes that the contracts with these key customers generally do not include a significant financing component. The allowance for doubtful accounts reflects the Group’s best estimate of probable losses inherent in the accounts receivable balance. The Group determines the allowance based on known troubled accounts, historical experience, and other currently available evidence. There was no activity in the allowance for doubtful accounts for the years presented as these key customers are of a good credit reputation and always make the payment timely.

The opening balance of accounts receivable from these key customers as of January 1, 2017 was RMB45,021. As of December 31, 2017 and 2018, accounts receivable were RMB253,896 and RMB372,702, respectively.

Contract liabilities consist of deferred revenue related to the Group’s provision of installation services, where there is still an obligation to be fulfilled by the Group. The contract liabilities will be recognized as revenue when all of the revenue recognition criteria are met.

The opening balance of deferred revenue as of January 1, 2017 was RMB29. As of December 31, 2017 and 2018, deferred revenue were RMB146 and RMB1,276, respectively. During the years ended December 31, 2016, 2017 and 2018, the Group recognized revenue of installation services amounted to RMB57, RMB716 and RMB14,635, respectively. The Group expects to recognize approximately RMB1,276 of the unearned amount for the Group’s remaining performance obligations related to installation services in 2019.

During the years ended December 31, 2016, 2017 and 2018, the Group does not have any arrangement where the performance obligations have already been satisfied in the past period, but the corresponding revenue is only recognized in a later period.

(p)	Cost of revenues

Cost of revenues consists primarily of material costs, warranty, consignment manufacturing cost, salaries and benefits for staff engaged in production activities and related expenses that are directly attributable to the production of products.

(q)	Research and development expenses

Research and development expenses primarily consist of salaries and benefits as well as share-based compensation for research and development personnel, materials, general expenses and depreciation expenses associated with research and development activities.

(r)	Selling and marketing expenses

Selling and marketing expenses consist primarily of (i) advertising and market promotion expenses, (ii) shipping expenses and (iii) salaries and welfare for sales and marketing personnel. The advertising and market promotion expenses amounted to RMB8,065, RMB39,638 and RMB130,796 for the years ended December 31, 2016, 2017 and 2018, respectively. The shipping expenses amounted to RMB2,633, RMB20,044 and RMB140,456 for the years ended December 31, 2016, 2017 and 2018, respectively.

(s)	General and administrative expenses

General and administrative expenses consist primarily of (i) share-based compensation for management and administrative personnel, and (ii) salaries and welfare for general and administrative personnel.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(t)	Government subsidies

Government subsidies represent government grants received from local government authorities to encourage the Group’s technology and innovation. The Group records such government subsidies as other income in the consolidated statements of comprehensive (loss) income when it has fulfilled all of its obligation related to the subsidy. The Group recorded RMB140, RMB1,278 and RMB1,440 of subsidy income for the years ended December 31, 2016, 2017 and 2018, respectively.

(u)	Employee benefits

PRC Contribution Plan

Full time employees of the Group in the PRC participate in a government mandated defined contribution plan, pursuant to which certain pension benefits, medical care, employee housing fund and other welfare benefits are provided to the employees. Chinese labor regulations require that the PRC subsidiary and VIEs of the Group make contributions to the government for these benefits based on certain percentages of the employees' salaries, up to a maximum amount specified by the local government. The Group has no legal obligation for the benefits beyond the contributions made. The total amounts of such employee benefit expenses, which were expensed as incurred, were approximately RMB3,199, RMB8,016 and RMB18,889 for the years ended December 31, 2016, 2017 and 2018, respectively.

(v)	Share-based compensation

Share-based compensation expenses arise from share-based awards, mainly including Restricted Shares held by the Founder or held by the Founder on behalf of certain key management founders and share options for the purchase of ordinary shares. The Company accounts for share-based awards granted to the Founder and employees in accordance with ASC 718 Stock Compensation.

Before the Reorganization, the Restricted Shares held by the Founders were subject to a repurchase feature under which Xiaomi shall purchase the interest held by Founders at the original investment amount if the Founders voluntarily terminate their employment with Foshan Viomi. The Restricted Shares were classified as equity classified awards as the underlying shares of the awards are ordinary shares of Foshan Viomi and the awards do not contain any of the characteristics of liability awards described in ASC718. The Restricted Shares are accounted for as share-based compensation based on the grant date fair value over the vesting period.

After the Reorganization completed in July 2015, the repurchase feature remains, however, it became the Company’s right, and not the obligation to repurchase. With respect to the remaining unvested interest granted to the Founder on behalf of certain key management founders, the underlying shares changed from ordinary shares of Foshan Viomi to Class A ordinary shares of the Company. These shares remain to be equity classified awards as they do not contain any characteristics of a liability award and were continually accounted for as share-based compensation based on the grant date fair value over the remaining vesting period. With respect to the remaining unvested interest granted to the Founder, the underlying shares changed from ordinary shares of Foshan Viomi to redeemable Class B Ordinary Shares of the Company, which are redeemable convertible shares. These awards have been reclassified as liability classified awards as the underlying Class B Ordinary Shares are redeemable at a fixed price plus 6% interest per year at the option of the holder if there is no qualified IPO after a certain period of time. According to ASC718, such awards effectively consist of: (1) a liability component representing the Company’s obligation to pay the redemption price if the holder chooses to redeem, and (2) an equity component representing the fair value of the upside potential of the Class B Ordinary Shares, measured using an option pricing model. At the time of the modification, the Company compared the fair value of the original award immediately before the modification, and the total fair value of the liability component and the equity component immediately after the modification. The incremental compensation amount is recognized over the remaining vesting period. The amount related to the liability component is recorded as a liability measured at the redemption price, subsequently accreted at 6% per year to reflect the increase in redemption price over time according to the terms of the Class B Ordinary Shares, until the award is settled. The liability award is considered settled only upon redemption or IPO, when the Class B Ordinary Shares are converted to Class A ordinary shares at which time, the redemption feature would expire.

Upon the completion of the IPO on September 25, 2018, all Class B Ordinary Shares were converted into Post-IPO Class B Ordinary Shares, the liability award had been settled.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

For share options for the purchase of ordinary shares granted to employees determined to be equity classified awards, the related share-based compensation expenses are recognized in the consolidated financial statements based on their grant date fair values which are calculated using the binomial option pricing model. The determination of the fair value is affected by the share price as well as assumptions regarding a number of complex and subjective variables, including the expected share price volatility, actual and projected employee share option exercise behavior, risk-free interest rates and expected dividends. The fair value of the ordinary shares is assessed using the income approach/discounted cash flow method, with a discount for lack of marketability, given that the shares underlying the awards were not publicly traded at the time of grant. Share-based compensation expenses are recorded net of estimated forfeitures using graded-vesting method during the service period requirement, such that expenses are recorded only for those share-based awards that are expected to ultimately vest.

(w)	Income taxes

Current income taxes are provided on the basis of net income for financial reporting purposes, adjusted for income and expense items which are not assessable or deductible for income tax purposes, in accordance with the regulations of the relevant tax jurisdictions. Deferred income taxes are accounted for using an asset and liability method. Under this method, deferred income taxes are recognized for the tax consequences of temporary differences by applying enacted statutory rates applicable to future years to differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities. The tax base of an asset or liability is the amount attributed to that asset or liability for tax purpose. The effect on deferred taxes of a change in tax rates is recognized in statement of comprehensive (loss) income in the period of change. A valuation allowance is provided to reduce the amount of deferred tax assets if it is considered more likely than not that some portion of, or all of the deferred tax assets will not be realized.

Uncertain tax positions

The guidance on accounting for uncertainties in income taxes prescribes a more likely than not threshold for financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. Guidance was also provided on the recognition of income tax assets and liabilities, classification of current and deferred income tax assets and liabilities, accounting for interest and penalties associated with tax positions, accounting for income taxes in interim periods, and income tax disclosures. Significant judgment is required in evaluating the Group’s uncertain tax positions and determining its provision for income taxes. The Group recognizes interests and penalties, if any, under accrued expenses and other current liabilities on its balance sheet and under other expenses in its statement of comprehensive (loss) income. The Group did not recognize any interest and penalties associated with uncertain tax positions for the years ended December 31, 2016, 2017 and 2018. As of December 31, 2017 and 2018, the Group did not have any significant unrecognized uncertain tax positions.

(x)	Comprehensive (loss) income

Comprehensive (loss) income consists of two components, net income and other comprehensive (loss) income, net of tax. Other comprehensive (loss) income refers to revenue, expenses, and gains and losses that are recorded as an element of shareholders’ equity but are excluded from net income. The Group’s other comprehensive (loss) income consists of foreign currency translation adjustments from its entities not using the RMB as their functional currency. Comprehensive (loss) income is reported in the consolidated statements of comprehensive (loss) income.

(y)	Statutory reserves

The Company's subsidiaries and VIEs established in the PRC are required to make appropriations to certain non-distributable reserve funds.

In accordance with the laws applicable to the Foreign Investment Enterprises established in the PRC, the Company's subsidiaries registered as wholly-owned foreign enterprise have to make appropriations from their annual after-tax profits (as determined under generally accepted accounting principles in the PRC(“PRC GAAP”)) to reserve funds including general reserve fund, enterprise expansion fund and staff bonus and welfare fund. The appropriation to the general reserve fund must be at least 10% of the annual after-tax profits calculated in accordance with PRC GAAP. Appropriation is not required if the general reserve fund has reached 50% of the registered capital of the company. Appropriations to the enterprise expansion fund and staff bonus and welfare fund are made at the respective company's discretion.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

In addition, in accordance with the PRC Company Laws, the Group's VIEs registered as Chinese domestic company must make appropriations from its annual after-tax profits as determined under the PRC GAAP to non-distributable reserve funds including statutory surplus fund and discretionary surplus fund. The appropriation to the statutory surplus fund must be 10% of the annual after-tax profits as determined under PRC GAAP. Appropriation is not required if the statutory surplus fund has reached 50% of the registered capital of the company. Appropriation to the discretionary surplus fund is made at the discretion of the Company.

The use of the general reserve fund, enterprise expansion fund, statutory surplus fund and discretionary surplus fund are restricted to offsetting of losses or increasing of the registered capital of the respective company. The staff bonus and welfare fund is a liability in nature and is restricted to fund payments of special bonus to employees and for the collective welfare of all employees. None of these reserves are allowed to be transferred to the Company in terms of cash dividends, loans or advances, nor can they be distributed except under liquidation.

The Group’s VIE, Foshan Viomi, made no appropriation to these statutory reserve funds for the year ended December 31, 2018 as Foshan Viomi’s profit appropriation made to the reserve fund reached the maximum required amount of 50% of its registered capital. Other PRC entities did not make any appropriation to its general reserve fund, statutory surpluses fund, discretionary surplus fund, and the staff bonus and welfare fund for the years reported, as they reported accumulated losses.

(z)	(Loss) Income per share

Basic (loss) income per share is computed by dividing net (loss) income attributable to ordinary shareholders, considering the accretion of redemption feature and cumulative dividend related to the Company’s redeemable convertible preferred shares and Class B Ordinary Shares, and undistributed earnings allocated to redeemable convertible preferred shares, Class B Ordinary Shares and unvested Class A ordinary shares as unvested Class A ordinary shares are also entitled to participating dividends, by the weighted average number of ordinary shares outstanding during the period using the two-class method. Under the two-class method, net income is allocated between ordinary shares and other participating securities based on their participating rights. Net losses are not allocated to other participating securities if based on their contractual terms they are not obligated to share the losses. After the IPO, net (loss)/income per ordinary share are computed on Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares together, because both classes have the same dividend rights in the Company’s undistributed net income.

Diluted (loss) income per share is calculated by dividing net (loss) income attributable to ordinary shareholders, as adjusted for the effect of dilutive ordinary equivalent shares, if any, by the weighted average number of ordinary and dilutive ordinary equivalent shares outstanding during the period. Ordinary equivalent shares consist of ordinary shares issuable upon the conversion of the redeemable convertible preferred and Class B Ordinary shares, using the if-converted method, and shares issuable upon the exercise of share options using the treasury stock method. Ordinary equivalent shares are not included in the denominator of the diluted (loss) income per share calculation when inclusion of such share would be anti-dilutive.

(aa)	Related parties

Parties are considered to be related if one party has the ability, directly or indirectly, to control the other party or exercise significant influence over the other party in making financial and operating decisions. Parties are also considered to be related if they are subject to common control or significant influence, such as a family member or relative, shareholder, or a related corporation.

(bb)	Segment reporting

Based on the criteria established by ASC 280 “Segment Reporting”, the Group's chief operating decision maker has been identified as the Chairman of the Board of Directors/CEO, who reviews consolidated results of the Group when making decisions about allocating resources and assessing performance. The Group has internal reporting of revenue, cost and expenses by nature as a whole. Hence, the Group has only one operating segment. The Company is domiciled in the Cayman Islands while the Group mainly operates its businesses in the PRC and earns substantially all of the revenues from external customers attributed to the PRC.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(cc)	Newly issued accounting pronouncements

In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (Topic 842) "Leases." Topic 842 supersedes the lease requirements in Accounting Standards Codification (ASC) Topic 840, "Leases." Under Topic 842, lessees are required to recognize assets and liabilities on the balance sheet for most leases and provide enhanced disclosures. Leases will continue to be classified as either finance or operating. The Group will adopt the new standard using the optional transition method (from ASU 2018-11, Leases Targeted Improvements) for fiscal years and interim periods within 2019. As permitted under the transition guidance, the Company will carry forward the assessment of whether the existing contracts contain or are leases, classification of the leases and remaining lease terms. Based on the portfolio of leases as of December 31, 2018, approximately RMB9,274 of right of use assets and RMB9,168 of lease liabilities will be recognized on our balance sheet upon adoption, primarily relating to real estate.

In June 2016, the FASB issued ASU 2016-13: Financial Instruments-Credit Losses (Topic 326), which requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets measured at amortized cost. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early application will be permitted for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Group is in the process of evaluating the impact of adopting this guidance.

In June 2018, the FASB issued ASU 2018-07, Improvements to Nonemployee Share-Based Payment Accounting: The amendments in this Update expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. An entity should apply the requirements of Topic 718 to nonemployee awards except for specific guidance on inputs to an option pricing model and the attribution of cost (that is, the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). The amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. The amendments also clarify that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606. The amendments in this Update are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company does not expect ASU 2018-07 to have a material impact to the Company’s consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. The amendments in this standard will remove, modify and add certain disclosures under ASC Topic 820, Fair Value Measurement, with the objective of improving disclosure effectiveness. ASU 2018-13 will be effective for the Group’s fiscal year beginning January 1, 2020, with early adoption permitted. The transition requirements are dependent upon each amendment within this update and will be applied either prospectively or retrospectively. The Company does not expect ASU 2018-13 to have a material impact to the Company’s consolidated financial statements.

Concentration and Risks

12 Months Ended

Dec. 31, 2018

Risks And Uncertainties [Abstract]

CONCENTRATION AND RISKS

3.	CONCENTRATION AND RISKS

(a)	Foreign exchange risk

The revenues and expenses of the Group’s entities in the PRC are generally denominated in RMB and their assets and liabilities are denominated in RMB. The RMB is not freely convertible into foreign currencies. Remittances of foreign currencies into the PRC or remittances of RMB out of the PRC as well as exchange between RMB and foreign currencies require approval by foreign exchange administrative authorities and certain supporting documentation. The State Administration for Foreign Exchange, under the authority of the People’s Bank of China, controls the conversion of RMB into other currencies.

3.	CONCENTRATION AND RISKS (Continued)

(b)	Credit risk

Financial instruments that potentially expose the Group to credit risk consist primarily of cash and cash equivalents, restricted cash, short-term investments, accounts receivable and amounts due from related parties. The Group places its cash and cash equivalents, restricted cash and short-term investments with financial institutions with high credit ratings and quality. There has been no recent history of default in relation to these financial institutions and credit risk is immaterial.

The Group conducts credit evaluations of third-party customers and related parties, and generally does not require collateral or other security from its third-party customers and related parties. The Group establishes an allowance for doubtful accounts primarily based upon the age of the receivables and factors surrounding the credit risk of specific third-party customers and related parties.

Accounts receivable from third-parties concentration of credit risk as below:

	As of December 31,
	2017					2018
	RMB					RMB
Company A	—		—				58,766		53	%
Company B	—		—				36,734		33	%
Company C		2,778		64	%	*		*

Less than 10%

Other receivables from related parties concentration of credit risk as below:

	As of December 31,
	2017				2018
	RMB				RMB
Xiaomi Inc.		24,160	42	%		112,320	100	%
Xiaomi H.K. Limited (“Xiaomi H.K.”)		33,448	58	%		—	—

(c)	Revenue concentration risk

	Year ended December 31,
	2016				2017				2018
	RMB				RMB				RMB
Xiaomi Telecommunication Technology		299,827	96	%		739,464	85	%		1,311,852	51	%

The revenue generated from Xiaomi included sale of both Xiaomi-branded and Viomi-branded products. Revenue from sale of Viomi-branded products amounted to RMB19,326, RMB84,514 and RMB136,520 for the years ended December 31, 2016, 2017 and 2018, respectively.

Cash and Cash Equivalents

12 Months Ended

Dec. 31, 2018

Cash And Cash Equivalents [Abstract]

Cash and Cash Equivalents

4.	CASH AND CASH EQUIVALENTS

Cash and cash equivalents represent cash on hand and demand deposits placed with banks or other financial institution. Cash and cash equivalents balance as of December 31, 2017 and 2018 primarily consist of the following currencies:

	As of December 31, 2017				As of December 31, 2018
			RMB				RMB
	Amount		equivalent		Amount		equivalent
US$		11,163		73,001		88,529		607,596
RMB		206,951		206,951		332,702		332,702
Total				279,952				940,298

Restricted Cash

12 Months Ended

Dec. 31, 2018

Cash And Cash Equivalents [Abstract]

RESTRICTED CASH

5.	RESTRICTED CASH

As of December 31, 2018, the Group held restricted cash of RMB29,550 in designated bank accounts for issuance of bank acceptance notes.

Short-Term Investments

12 Months Ended

Dec. 31, 2018

Schedule Of Investments [Abstract]

SHORT-TERM INVESTMENTS

6.	SHORT-TERM INVESTMENTS

Short-term investments represent structured deposits with maturities of less than one year. In accordance with ASC 825, the Company elected the fair value method at the date of initial recognition and carried these short-term investments at fair value. Changes in the fair value are reflected in the consolidated statements of comprehensive (loss) income as short-term investment income. Short-term investments balance as of December 31, 2018 is primarily denominated in the following currencies:

	As of December 31, 2017				As of December 31, 2018
			RMB				RMB
	Amount		equivalent		Amount		equivalent
RMB		—		—		100,022		100,022
US$		—		—		10,049		68,971
Total				—				168,993

Inventories

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

INVENTORIES

7.	INVENTORIES

Inventories consisted of the followings:

	As of December 31,
	2017		2018
	RMB		RMB
Finished goods		13,956		136,494
Raw materials		36,736		95,481
Inventories		50,692		231,975

For the years ended December 31, 2016, 2017 and 2018, the Group recorded write-down of RMB1,658, RMB81 and RMB1,059 for obsolete inventories, respectively.

Prepaid Expenses and Other Assets

12 Months Ended

Dec. 31, 2018

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

PREPAID EXPENSES AND OTHER ASSETS

8.	PREPAID EXPENSES AND OTHER ASSETS

	As of December 31,
	2017		2018
	RMB		RMB
Advances to suppliers		14,428		23,549
Other receivables		3,054		15,361
Prepayment for equipment		—		3,636
Other current assets		5,525		7,745
Rental deposits		276		235
Total		23,283		50,526
Less: non-current portion		—		(3,636	)
Prepaid expenses and other assets-current portion		23,283		46,890

Property, Plant and Equipment, Net

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT, NET

9.	PROPERTY, PLANT AND EQUIPMENT, NET

Property, plant and equipment, net consisted of the following:

	As of December 31,
	2017			2018
	RMB			RMB
Computers and equipment		5,815			16,270
Vehicle		508			508
Total		6,323			16,778
Less: accumulated depreciation		(3,237	)		(5,477	)
Property, plant and equipment, net		3,086			11,301

The Group had recorded depreciation expense of RMB1,222, RMB1,680 and RMB2,244 for the years ended December 31, 2016, 2017 and 2018, respectively. No impairment was recorded for the years ended December 31, 2016, 2017 and 2018.

Accrued Expenses and Other Liabilities

12 Months Ended

Dec. 31, 2018

Payables And Accruals [Abstract]

ACCRUED EXPENSES AND OTHER LIABILITIES

10.	ACCRUED EXPENSES AND OTHER LIABILITIES

	As of December 31,
	2017			2018
	RMB			RMB
Freight payable		9,799			50,680
Other tax payable		15,359			42,076
Accrued payroll and welfare		16,304			39,700
Product warranty		13,909			12,744
Marketing and promotion expenses		1,000			10,710
Professional fee payables		—			10,340
Installation fee payables		—			8,133
Deferred revenue		146			1,276
Deposits received related to unvested shares		496			—
Other current liabilities		4,871			25,789
Total		61,884			201,448
Less: non-current portion		(460	)		(518	)
Accrued expenses and other liabilities-current portion		61,424			200,930

Product warranty activities were as follows:

	Product Warranty
	RMB
Balance at December 31, 2016		2,483
Provided during the year		17,806
Utilized during the year		(6,380	)
Balance at December 31, 2017		13,909
Provided during the year		19,775
Utilized during the year		(20,940	)
Balance at December 31, 2018		12,744

Revenue

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

REVENUE

11.

REVENUE

	Year ended December 31, 2016
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		273,282		206,679		66,603
Smart water purification systems		250,442		191,848		58,594
Other smart products		22,840		14,831		8,009
- Consumable products		19,376		10,644		8,732
- Other products		19,859		15,166		4,693
Total of sales of product		312,517		232,489		80,028
Rendering of services
- Installation services		57		55		2
Total		312,574		232,544		80,030

	Year ended December 31, 2017
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		712,317		499,739		212,578
Smart water purification systems		570,784		399,788		170,996
Smart kitchen products		50,656		34,987		15,669
Other smart products		90,877		64,964		25,913
- Consumable products		87,500		48,123		39,377
- Other products		72,686		49,489		23,197
Total of sales of product		872,503		597,351		275,152
Rendering of services
- Installation services		716		685		31
Total		873,219		598,036		275,183

	Year ended December 31, 2018
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		2,081,273		1,514,344		566,929
Smart water purification systems		930,178		614,829		315,349
Smart kitchen products		744,990		596,005		148,985
Other smart products		406,105		303,510		102,595
- Consumable products		141,940		67,433		74,507
- Other products		323,381		247,717		75,664
Total of sales of product		2,546,594		1,829,494		717,100
Rendering of services
- Installation services		14,635		13,938		697
Total		2,561,229		1,843,432		717,797

Income Tax (Benefits) Expenses

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

INCOME TAX (BENEFITS) EXPENSES

12.	INCOME TAX (BENEFITS) EXPENSES

Cayman Islands

Under the current tax laws of Cayman Islands, the Company and its subsidiaries are not subject to tax on income or capital gains. Besides, upon payment of dividends by the Company to its shareholders, no Cayman Islands withholding tax will be imposed.

Hong Kong

Under the current Hong Kong Inland Revenue Ordinance, the subsidiary of the Group in Hong Kong are subject to 16.5% Hong Kong profit tax on its taxable income generated from operations in Hong Kong. Additionally, payments of dividends by the subsidiary incorporated in Hong Kong to the Company are not subject to any Hong Kong withholding tax.

PRC

In accordance with the Enterprise Income Tax Law (“EIT Law”), Foreign Investment Enterprises (“FIEs”) and domestic companies are subject to Enterprise Income Tax (“EIT”) at a uniform rate of 25%. The subsidiaries and VIEs of the Group in the PRC are subject to a uniform income tax rate of 25% for years presented. Certified High and New Technology Enterprises (“HNTE”) are entitled to a favorable statutory tax rate of 15%. According to a policy promulgated by the State Tax Bureau of the PRC and effective from 2008 onwards, enterprises engaged in research and development activities are entitled to claim an additional tax deduction amounting to 50% of the qualified research and development expenses incurred in determining its tax assessable profits for that year. The additional tax deduction has been increased from 50% of the qualified research and development expenses to 75%, effective from 2018 to 2020, according to a new tax incentives policy promulgated by the State Tax Bureau of the PRC in September 2018 (“Super Deduction”).

Withholding tax on undistributed dividends

Under the CIT Law and its implementation rules, the profits of a foreign-invested enterprise arising in 2008 and thereafter that are distributed to its immediate holding company outside the PRC are subject to withholding tax at a rate of 10%. A lower withholding tax rate will be applied if there is a beneficial tax treaty between the PRC and the jurisdiction of the foreign holding company. A holding company in Hong Kong, for example, will be eligible, with approval of the PRC local tax authority, to be subject to a 5% withholding tax rate under the Arrangement Between the PRC and the Hong Kong Special Administrative Region on the Avoidance of Double Taxation and Prevention of Fiscal Evasion with Respect to Taxes on Income and Capital if such holding company is considered to be a non-PRC resident enterprise and holds at least 25% of the equity interests in the PRC foreign-invested enterprise distributing the dividends. However, if the Hong Kong holding company is not considered to be the beneficial owner of such dividends under applicable PRC tax regulations, such dividend will remain subject to withholding tax at a rate of 10%. Aggregate undistributed earnings of the Group entities located in the PRC that are available for distribution to the Company as of December 31, 2017 and 2018 are approximately RMB95,658 and RMB282,130, respectively. The Company does not intend to have any of its subsidiaries located in PRC distribute any undistributed earnings of such subsidiaries in the foreseeable future, but rather expects that such earnings will be reinvested by such subsidiaries for their PRC operations. Accordingly, no withholding tax was recorded as of December 31, 2017 and 2018.

Composition of income tax expense

The current and deferred components of income taxes appearing in the consolidated statements of comprehensive (loss) income are as follows:

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Current tax expenses		—			15,519			26,247
Deferred tax benefit		(2,247	)		(801	)		(2,186	)
Income tax (benefits) expenses		(2,247	)		14,718			24,061

12.	INCOME TAX (BENEFITS) EXPENSES (Continued)

Reconciliation between the income tax expenses computed by applying the PRC enterprise tax rate to income before income taxes and actual provision were as follows:

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Income from operations in the PRC		13,546			106,868			93,910
Income (loss) from overseas entities		466			1,090			(4,499	)
Income before income tax		14,012			107,958			89,411

Tax expense at PRC enterprise income tax rate of 25%		3,503			26,990			22,353
Income tax on tax holiday⁽¹⁾		(1,414	)		(10,989	)		(9,632	)
Tax effect of permanence differences⁽²⁾		(1,187	)		(2,640	)		(7,871	)
Effect of income tax rate change⁽³⁾		3,179			—			—
Change in valuation allowance⁽⁴⁾		(7,756	)		760			602
Effect of share-based compensation		1,587			873			17,492
Effect of income tax in jurisdictions other than the PRC		(159	)		(276	)		1,117
Income tax (benefits) expenses		(2,247	)		14,718			24,061

(1)

The income tax reversals resulting from the preferential income tax rates that Foshan Viomi was entitled to as an HNTE is included in the “Income tax on tax holidays” in the table above. The favorable 15% tax rate will be eligible for three years starting from 2016.

(2)

The permanent book-tax differences mainly consisted of R&D super deductions.

(3)

Effect of income tax rate change represents the effect due to the change in the applicable tax rate in calculating deferred income tax as a result of Foshan Viomi’s qualification of HNTE in 2016.

(4)

As of December 31, 2015, the Group provided full valuation allowance for the deferred tax assets as it has incurred net accumulated operating losses for income tax purposes since its inception. The Group believed that it is more likely than not that these net accumulated operating losses and other deferred tax assets will not be utilized in the near future. For the years ended December 31, 2016, 2017 and 2018, Foshan Viomi reported taxable profit and the Group believes that it is more likely than not that the deferred tax assets of Foshan Viomi will be utilized in the future. Therefore, valuation allowances related to deferred tax assets of Foshan Viomi have been released in 2016. Valuation allowance for the years ended December 31, 2017 and 2018 are related to the deferred tax assets of certain group entities which reported loss. The Group believed that it is more likely than not that these the deferred tax assets of these entities will not be utilized. Therefore, valuation allowance has been provided.

The per share effect of the tax holidays are as follows:

	Year ended December 31,
	2016	2017	2018
	RMB	RMB	RMB
Net income per share effect – basic	0.12	0.53		0.22
Net income per share effect – diluted	0.12	0.41		0.20

12.	INCOME TAX (BENEFITS) EXPENSES (Continued)

Deferred tax assets and deferred tax liabilities

The significant components of the Group’s deferred tax assets were as follows:

	As of December 31,
	2017			2018
	RMB			RMB
Inventory write downs		541			421
Accrued expenses and others		2,485			4,616
Deferred income		22			191
Net operating loss carry forwards		952			1,560
Total deferred tax assets		4,000			6,788
Less: valuation allowance		(952	)		(1,554	)
Deferred tax assets, net		3,048			5,234

Movement of valuation allowance

	Year ended December 31,
	2016			2017		2018
	RMB			RMB		RMB
Balance at beginning of the year		7,948			192		952
Provided		190			760		602
Reversals		(7,946	)		—		—
Balance at end of the year		192			952		1,554

Uncertain tax positions

The Group evaluates the level of authority for each uncertain tax position (including the potential application of interest and penalties) based on the technical merits, and measures the unrecognized benefits associated with the tax positions. As of December 31, 2017 and 2018, the Group did not have any significant unrecognized uncertain tax positions.

According to the PRC Tax Administration and Collection Law, the statute of limitations is generally three years and can be extended to five years under special circumstances.

Ordinary Shares

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

ORDINARY SHARES

13.	ORDINARY SHARES

The Company’s original Memorandum and Articles of Association authorizes the Company to issue 346,545,454 class A ordinary shares with a par value of US$0.0001 per share. As of December 31, 2017, the Company had 25,363,636 class A ordinary shares outstanding. Each ordinary share is entitled to one vote. The holders of ordinary shares are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to prior rights of holders of all other classes of shares outstanding.

On August 23, 2018, the Company issued 4,000,000 class A ordinary shares at par value to Mr. Chen’s wholly-owned entity Viomi Limited to award his contribution to the Company’s development. Such shares were immediately vested. The issuance of such shares is accounted for as a share-based compensation to Mr. Chen. The issuance date fair value was estimated to be approximately US$3.30 per share.

13.	ORDINARY SHARES (Continued)

On the same day, the Company effected a share split whereby each of the Company’s then authorised and outstanding ordinary shares and preferred shares, par value of $0.0001 each, was divided into ten ordinary shares and preferred shares of the same series, par value US$0.00001 each, respectively. All shareholders then surrendered 90% of their after-share-split outstanding shares back to the Company for cancellation. After the share split and the surrender of shares for cancellation, the number of the Company’s outstanding ordinary and preferred shares remained unchanged. The par value per ordinary share has been retroactively revised as if it had been adjusted in proportion to the share split.

Upon the completion of the Company’s IPO on September 25, 2018 (Note 1(a)), the Company authorized (i) 4,800,000,000 Post-IPO Class A Ordinary Shares of a par value of US$0.00001 each, (ii) 150,000,000 Post-IPO Class B Ordinary Shares of a par value of US$0.00001 each and (iii) 50,000,000 shares of a par value of US$0.00001 each of such class or classes (however designated) as the board of directors may determine in accordance with post-offering amended and restated memorandum and articles of association. Holders of Post-IPO Class A Ordinary Shares and Post-IPO Class B Ordinary Shares have the same rights, except for voting rights and conversion rights. Each Post-IPO Class A Ordinary Share is entitled to one vote, and each Post-IPO Class B Ordinary Share is entitled to ten (10) votes, voting together as one class. Each Post-IPO Class B Ordinary Share is convertible into one Post-IPO Class A Ordinary Share at any time by the holder thereof. Post-IPO Class A Ordinary Shares are not convertible into Post-IPO Class B Ordinary Shares under any circumstances. Upon any transfer of Post-IPO Class B Ordinary Shares by a holder to any person or entity other than holders of Post-IPO Class B Ordinary Shares or their affiliates, such Post-IPO Class B Ordinary Shares shall be automatically and immediately converted into the equivalent number of Post-IPO Class A Ordinary Shares.

Prior to the completion of the IPO, 16,145,454 issued class A ordinary shares held by certain key management founders, 33,818,182 issued Class B Ordinary Shares held by Red Better, and 67,636,364 issued Class B Ordinary Shares held by Mr. Chen’s wholly-owned entity Viomi Limited was automatically converted by way of re-designation and re-classification into Post-IPO Class B Ordinary Shares on a one-for-one basis, and the rest of the outstanding class A ordinary shares, the rest of the outstanding class B Ordinary Shares, and all outstanding Series A Preferred Shares was automatically converted by way of re-designation and re-classification into Post-IPO Class A Ordinary Shares on a one-for-one basis.

As of December 31, 2018, the Company had 90,200,000 Post-IPO Class A Ordinary Shares and 117,600,000 Post-IPO Class B Ordinary Shares outstanding, respectively.

Redeemable Convertible Preferred and Class B Ordinary Shares

12 Months Ended

Dec. 31, 2018

Temporary Equity Disclosure [Abstract]

REDEEMABLE CONVERTIBLE PREFERRED AND CLASS B ORDINARY SHARES

14.	REDEEMABLE CONVERTIBLE PREFERRED AND CLASS B ORDINARY SHARES

As described in note1 (a), pursuant to a shares purchase agreement, the Company issued certain Class B Ordinary Shares to Mr. Chen, Red Better and Shunwei during the Reorganization, and the Company also issued totaling 18,181,818 shares (with par value of US$0.0001) of Series A Preferred Shares for US$1.1000 per share with total consideration of US$20,000, including conversion of the outstanding bridge loans of US$5,250.

The significant terms of the Series A Preferred Shares and Class B Ordinary Shares issued by the Company are as follows:

Conversion rights

Optional Conversion

Each holder of Series A Preferred Shares and Class B Ordinary Shares shall have the right, at such holder’s sole discretion, to convert all or any portion of the Series A Preferred Shares and Class B Ordinary Shares into Class A Ordinary Shares at any time. The conversion rate for Series A Preferred Shares and Class B Ordinary Shares shall be determined by dividing applicable Share Issue Price by the conversion price then in effect at the date of the conversion. The initial conversion price will be the applicable Share Issue Price (i.e., a 1-to-1 initial conversion ratio), and thereafter shall be subject to adjustment and readjustment from time to time as hereinafter provided, being no less than par value. Adjustments of conversion ratios include the following:

(1)

Adjustment of applicable conversion price upon issuance of additional ordinary shares below the applicable conversion price.

(2)

Adjustments for share dividends, subdivisions, combinations or consolidations of class A ordinary shares.

(3)

Adjustments for other distributions.

(4)

Adjustments for reclassification, exchange and substitution.

14.	REDEEMABLE CONVERTIBLE PREFERRED AND CLASS B ORDINARY SHARES (Continued)

Automatic Conversion

Each Series A Preferred Share and Class B Ordinary Share shall automatically be converted into class A ordinary shares, at the then applicable preferred share conversion price upon the closing of a Qualified IPO;

Voting rights

Each Series A Preferred Share and Class B Ordinary Share shall carry a number of votes equal to the number of class A ordinary shares then issuable upon its conversion into class A ordinary shares at the record date for determination of the shareholders entitled to vote on such matters, or, if no such record date is established, at the date such vote is taken or any written consent of shareholders is solicited. To the extent that applicable law, Memorandum and Articles of the Company require the Series A Preferred Shares and Class B Ordinary Shares to vote separately as a class with respect to any matters, the Series A Preferred Shares and Class B Ordinary Shares shall vote separately as a class with respect to such matters. Otherwise, the holders of Series A Preferred Shares and Class B Ordinary Shares and class A ordinary shares shall vote together as a single class.

Redemption rights

Redemption Condition for Series A Preferred Shares and Class B Ordinary Shares:

The Series A Preferred Shares and Class B Ordinary Shares are redeemable at any time after the earlier of:

the fifth anniversary of the date on which the closing of the shares issuance pursuant to the share purchase agreement (the “Closing Date”), if the Company has not consummated a Qualified IPO;

ii)

any material breach by the Founder or the Group, of any representatives, warranties or covenants of the transaction documents and not cured within six (6) months (the “Redemption Start Date”), then subject to the applicable laws of the Cayman Islands and, if so requested by any investor, the Company and the Founder shall redeem all or part of the outstanding Series A Preferred Shares and/or Class B Ordinary Shares held by such Investor (collectively, the “Redeemable Shares”) in cash out of funds legally available therefor.

The redemption price of each Series A Preferred Share and Class B Ordinary Share shall be the sum of the Series A Preferred Shares and Class B Ordinary Shares issuance price, respectively: Plus 6% compound interest return per annum on the issuance price; plus all declared but unpaid dividends per Series A Preferred Shares and Class B Ordinary Shares.

If the Company does not have sufficient cash or funds legally available to redeem any of the redeemable shares required to be redeemed, the Company and the Founder shall use their best effort to cause the remaining redeemable shares to be purchased, including without limitation, to seek, facilitate and procure third parties to acquire the remaining redeemable shares on terms and conditions acceptable to the relevant redemption holders.

Dividends rights

Holders of outstanding Series A Preferred Shares shall be entitled to receive dividends, out of any assets legally available therefor, prior and in preference to any declaration or payment of any dividend (whether in cash, in property or in shares of the capital of the Company) on the ordinary shares or any other class or series of shares of the Company, at the rate of eight percent (8%) of the preferred share issue price per share (as adjusted for any subdivisions, consolidations, bonus issues, reclassifications and the like) per annum on each Series A Preferred Shares, payable in U.S. dollars and annually when, as and if declared by the Board. Such distributions shall be cumulative. Holders of the Series A Preferred Shares shall also be entitled to receive any non-cash dividends declared by the Board on an as-converted basis.

After payment of the dividends distributed to the holders of Series A Preferred Shares, any additional dividends or distributions shall be distributed to the holders of Class B Ordinary Shares, prior and in preference to any declaration or payment of any dividend (whether in cash, in property or in shares of the capital of the Company) on the class A ordinary shares or any other class or series of shares of the Company, at the rate of eight percent (8%) of the deemed Class B Ordinary Share issue price per share (as adjusted for any subdivisions, consolidations, bonus issues, reclassifications and the like) per annum on each Class B Ordinary Share, payable in U.S. dollars and annually when, as and if declared by the

Board. Such distributions shall be cumulative. Holders of the Class B Ordinary Shares shall also be entitled to receive any non-cash dividends declared by the Board on an as-converted basis.

14.	REDEEMABLE CONVERTIBLE PREFERRED AND CLASS B ORDINARY SHARES (Continued)

Liquidation rights

Liquidation Preferences

In the event of any liquidation, dissolution or winding up of the Company, either voluntary or involuntary, all assets and funds of the Company legally available for distribution among holders of the outstanding Shares (on an as-converted to basis) in the following order and manner:

the holders of the Series A Preferred Shares shall be entitled to receive, prior to any distribution to the holders of the ordinary shares or any other class or series of shares then outstanding, an amount per Series A Preferred Share equal to (a) one hundred and fifty percent (150%) of the preferred share issue price, plus (b) all declared but unpaid dividends thereon (collectively, the “Preferred Share Preference Amount”). If the Company has insufficient assets to permit payment of the Preferred Share Preference Amount in full to all holders of Series A Preferred Shares, then the assets of the Company shall be distributed ratably to the holders of the Series A Preferred Shares in proportion to the full Preferred Share Preference Amount.

ii)

after the full Preferred Share Preference Amount on all outstanding Series A Preferred Shares has been paid, any remaining funds or assets of the Company legally available for distribution to shareholders shall be distributed to the holders of Class B Ordinary Shares, prior to the holders of the class A ordinary shares or any other class or series of shares then outstanding, an amount per Class B Ordinary Share equal to (a) one hundred and fifty percent (150%) of the deemed Class B Share issue price, plus (b) all declared but unpaid dividends thereon (collectively, the “Class B Share Preference Amount”, collectively with the Preferred Share Preference Amount, the “Preference Amount”). After the full Preferred Share Preference Amount has been paid, if the remaining assets are insufficient to permit payment of the Class B Share Preference Amount in full to all holders of Class B Ordinary Shares, then the remaining assets of the Company shall be distributed ratably to the holders of the Class B Ordinary Shares in proportion to the full Class B Share Preference Amount.

iii)

after the full Preference Amount on all outstanding Series A Preferred Shares and Class B Ordinary Shares has been paid, any remaining funds or assets of the Company legally available for distribution to shareholders shall be distributed on a pro rata, pari passu basis among the holders of the Preferred Shares (on an as-converted basis), together with the holders of the Ordinary Shares.

Liquidation Event

The following events shall be deemed as a liquidation, dissolution or winding up of the Company (each, a “Liquidation Event”):

(i)

any acquisition of the Company (whether by a sale of equity, merger or consolidation) in which in excess of 50% of the Company’s voting power outstanding before such transaction is transferred;

(ii)

a sale of all or substantially all of the Company’s assets and no substantial business operations will be continued by the Company.

Accounting of Series A Preferred Shares and Class B Ordinary Shares

The Company classified the Series A Preferred Shares and Class B Ordinary Shares as mezzanine equity in the consolidated balance sheets because they were redeemable at the holders’ option any time after a certain date and were contingently redeemable upon the occurrence of certain liquidation events outside of the Company’s control. The Series A Preferred Shares and Class B Ordinary Shares are recorded initially at fair value, net of issuance costs.

Prior to the Reorganization, the 40% initial equity interests of Foshan Viomi held by the Founder for himself has liquidation preference, and the 40% initial equity interests of Foshan Viomi held by Tianjin Jinxing has liquidation preference and also becomes redeemable in the event of a breach of contract by Foshan Viomi.

Upon completion of the Reorganization, both the Founder and Tianjin Jinxing’s equity interests in Foshan Viomi are exchanged into 67,636,364 Class B Ordinary Shares of the Company, respectively. After the Reorganization, the most significant change in the provision is the addition of redemption clause which allows the holders of the Class B Ordinary Shares to redeem the Class B Ordinary Shares if there are no Qualified IPO after the fifth anniversary of the Closing Date.

14.	REDEEMABLE CONVERTIBLE PREFERRED AND CLASS B ORDINARY SHARES (Continued)

This transaction was considered as an extinguishment of the previous equity interests and therefore, the Class B Ordinary Shares are measured at its fair value on the extinguishment date.

The Group recognizes changes in the redemption value ratable over the redemption period. Increases in the carrying amount of the redeemable preferred shares are recorded by charges against retained earnings, or in the absence of retained earnings, by charges as reduction of additional paid-in capital until additional paid-in capital is reduced to zero. Once additional paid-in capital is reduced to zero, the redemption value measurement adjustment is recognized as an increase in accumulated deficit.

The change in the balance of Series A Preferred Shares and Class B Ordinary Shares included in mezzanine equity for the years ended December 31, 2016, 2017 and 2018 are as follows:

	Series A Preferred Shares			Class B Ordinary Shares held by the Founder⁽¹⁾⁽²⁾			Class B Ordinary Shares- owned by Xiaomi⁽¹⁾			Total
	RMB			RMB			RMB			RMB
Balance as of January 1, 2016		133,573			51,057			204,230			388,860
Accretion of preferred shares		8,221			—			—			8,221
Foreign exchange		9,485			3,488			13,945			26,918
Balance as of December 31, 2016		151,279			54,545			218,175			423,999
Accretion of preferred shares		8,834			—			—			8,834
Foreign exchange		(9,068	)		(3,169	)		(12,668	)		(24,905	)
Balance as of December 31, 2017		151,045			51,376			205,507			407,928
Accretion of preferred shares		6,563			—			—			6,563
Foreign exchange		7,487			2,437			9,743			19,667
Conversion of Series A Preferred Shares and Class B Ordinary Shares to ordinary shares upon the completion of the IPO on September 25, 2018		(165,095	)		(53,813	)		(215,250	)		(434,158	)
Balance as of December 31, 2018		—			—			—			—

(1)

The carrying amount of Class B Ordinary Shares is higher than the redemption value, which is based on the original investment amount in 2014. Therefore no accretion was recorded for the years ended December 31, 2016, 2017 and 2018.

(2)

Out of the 67,636,364 Class B Ordinary Shares held by the Founder, 50,727,273 Class B ordinary shares held by the Founder pursuant to the restricted share arrangement is included in liability award.

Share-Based Compensation

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation

15.	SHARE-BASED COMPENSATION

Compensation expense recognized for share-based awards was as follows:

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Share-based compensation expenses
—Restricted shares owned by the Founder – equity component^(a)		6,051		2,670		826
—Restricted shares owned by the Founder – liability component^(a)		266		286		212
—Restricted shares owned by the Founder on behalf of certain key management founders^(a)		93		48		14
—Share options^(b)		4,168		2,817		25,391
—Shares awarded to Mr. Chen^(c)		—		—		90,168
Total share-based compensation expenses		10,578		5,821		116,611

15.	SHARE-BASED COMPENSATION (Continued)

(a)	Restricted Shares

As described in note 1 (a), the Founder and Xiaomi, made a capital contribution of RMB7,500 and RMB5,000, respectively, in exchange for 60% and 40% equity interests in Foshan Viomi, respectively. Out of the RMB7,500 invested by the Founder, RMB2,500 was invested by certain key management founders and held by the Founder on their behalf. For the equity interests held by the Founder for himself, these were ordinary shares in nature but with substantive liquidation preference, while for the equity interests held by the Founder on behalf of certain key management founders, these were the most subordinated class of equity of Foshan Viomi and did not carry any preference rights.

According to the agreement among the shareholders entered into in June 2014, the interest held by the Founders shall be subject to a repurchase feature under which Xiaomi shall purchase the interest held by the Founders at the original investment amount if the Founders voluntarily terminates their employment with Foshan Viomi. The repurchase feature shall lapse at a rate of 25% each year, consequently, the interests held by the Founders are accounted for as equity-classified share-based compensation with a vesting period of 4 years.

As discussed in note 2(v), after the Reorganization, the unvested awards held by the Founder on his own behalf consisted of a share-based compensation liability measured based on the redemption value and a share option component representing the value of upside potential of the Class B Ordinary Shares which is accounted for as an equity grant, while the unvested awards held by the Founder on behalf of certain key management founders continue to be equity-classified. As the share-based compensation expenses related to the equity component of the restricted shares owned by the Founder and the restricted shares held by the Founder on behalf of certain key management founders are recognized using graded vesting method, the expenses recognized in 2016 is higher than that of 2017 and 2018.

A summary of the Restricted Shares activity for the years ended December 31, 2016, 2017 and 2018 is presented below:

	Number of shares
	Restricted Shares held by the Founder on behalf of certain key management founders			Restricted Shares held by the Founder on his own behalf			Total
Outstanding at January 1, 2016		25,363,638			50,727,273			76,090,911
Vested		(8,454,546	)		(16,909,091	)		(25,363,637	)
Outstanding at December 31, 2016		16,909,092			33,818,182			50,727,274
Vested		(8,454,546	)		(16,909,091	)		(25,363,637	)
Outstanding at December 31, 2017		8,454,546			16,909,091			25,363,637
Surrender and cancellation⁽¹⁾		(5,918,182	)		—			(5,918,182	)
Vested		(2,536,364	)		(16,909,091	)		(19,445,455	)
Outstanding at December 31, 2018		—			—			—

(1)

In June 2018, the Board of Directors and the shareholders approved a transfer and surrender of shares plan, pursuant to which, Mr. Chen, who holds 33,818,182 Class A ordinary shares on behalf of certain key management founders through Viomi Limited, transferred 16,145,454 Class A ordinary shares to key management founders and surrendered the remaining 17,672,728 Class A ordinary shares to the Company. Out of the 17,672,728 Class A ordinary shares surrendered, 5,918,182 shares were unvested restricted shares. The cancellation of these 5,918,182 shares is accounted for as an acceleration of vesting of such shares and the unrecognised share-based compensation expenses related to these 5,918,182 shares have been recognised in the consolidated financial statements for the year ended December 31, 2018. The share-based compensation expenses recognised due to the acceleration of vesting is not material.

15.	SHARE-BASED COMPENSATION (Continued)

The table below shows the details of the movement of liability-classified awards with respect to unsettled 50,727,273 restricted shares granted to the Founder for the years ended December 31, 2016, 2017 and 2018:

	Liability-classified Awards (RMB)
	Restricted Shares held by the Founder on his own behalf
Balance as at January 1, 2016		4,181
Share-based compensation expenses		266
Foreign currency translation adjustment		103
Balance as at December 31, 2016		4,550
Share-based compensation expenses		286
Foreign currency translation adjustment		(98	)
Outstanding at December 31, 2017		4,738
Share-based compensation expenses		212
Foreign currency translation adjustment		408
Conversion of Restricted Shares to ordinary shares upon the completion of the IPO on September 25, 2018		(5,358	)
Outstanding at December 31, 2018		—

(b)	Share options

On September 17, 2015, the Board of Directors of the Company approved the establishment of 2015 Share Incentive Plan, the purpose of which is to provide an incentive for employees contributing to the Group. The 2015 Share Incentive Plan shall be valid and effective for 10 years from the grant date. The maximum number of shares that may be issued pursuant to all awards (including incentive share options) under 2015 Share Incentive Plan shall be 12,727,272 shares.

In June 2018, the Board of Directors and shareholders of the Company approved the 2018 Share Incentive Plan, pursuant to which the maximum aggregate number of shares which may be issued was initially 17,672,728 shares.

For the years ended December 31, 2016 and 2017, the Company granted 1,860,000 and 2,700,000 share options to employees pursuant to the 2015 Share Incentive Plan. With respect to the share options granted, 50% of the options will be vested after 24 months of the grant date and the remaining 50% will be vested in two equal installments over the following 24 months.

For the year ended December 31, 2018, the Company granted 5,460,000 and 670,000 share options to employees pursuant to the 2015 Share Incentive Plan and 2018 Share Incentive Plan, respectively. Among which, with respect to the 5,500,000 share options granted, 40% of the options will be vested after 24 months of the grant date and the remaining 60% will be vested in three equal installments over the following 36 months. With respect to 630,000 share options granted, 50% of the options will be vested after 24 months of the grant date and the remaining 50% will be vested in two equal installments over the following 24 months.

The Group calculated the estimated fair value of the options on the respective grant dates using the binomial option pricing model with assistance from independent valuation firms. Assumptions used to determine the fair value of share options granted during 2016, 2017 and 2018 are summarized in the following table:

	Year ended December 31,
	2016			2017		2018
Risk-free interest rate		2.86	%	3.06%-3.89%		3.62%~3.92%
Expected volatility	50.14%-50.15%			47.02%-49.44%		45.51%~46.99%
Expected life of option (years)	10			10			10
Expected dividend yield		—			—		—
Fair value per ordinary share	US$0.51			US$0.76-US$ 1.59		US$1.61-US$3.30

15.	SHARE-BASED COMPENSATION (Continued)

(1)	Risk-free interest rate

Risk-free interest rate was estimated based on the yield to maturity of China Government Bond with a maturity period close to the contractual term of the options.

(2)	Expected life of option (years)

Expected life of option (years) represents the expected years to vest the options.

(3)	Volatility

The volatility of the underlying ordinary shares during the life of the options was estimated based on the historical stock price volatility of comparable listed companies over a period comparable to the contractual term of the options.

(4)	Dividend yield

The dividend yield was estimated by the Group based on its expected dividend policy over the contractual term of the options.

(5)	Fair value per ordinary share

In determining the grant date fair value of the Company’s ordinary shares for purposes of recording share-based compensation expenses in connection with Restricted Shares owned by the Founder, Restricted Shares owned by the Founder on behalf of certain key management founders, and share options under the 2015 Share Incentive Plan and 2018 Share Incentive Plan, the Company, with the assistance of an independent valuation firm, evaluated the use of three generally accepted valuation approaches: market, cost and income approaches to estimate the enterprise value of the Company and income approach (discounted cash flow, or DCF method) was relied on for value determination with market approach (guideline companies method, or GCM) taken as reference.

DCF method of the income approach involves applying appropriate weighted average cost of capital (“WACC”), to discount the future cash flows forecast, based on the Company’s best estimates as of the valuation date, to present value. The WACC was determined based on a consideration of the factors including risk-free rate, comparative industry risk, equity risk premium, company size and non-systematic risk factors.

GCM under the market approach was adopted as reference of the equity valuation for the company. GCM employs trading multiples method of selected public comparable companies including trailing and leading enterprise value/revenue multiples.

In deriving the equity value of each class of shares, the Company applied the option pricing method. The option pricing method treats different classes of shares as call options on the total equity value, with exercise prices based on the liquidation preference or redemption amount of the certain classes of shares. Under this method, the ordinary share has value only if the fund available for distribution to shareholders exceeds the value of liquidation preference or redemption amounts at the time of a liquidity event, assuming the enterprise has funds available to make liquidation preference or redemption. Given the nature of the different classes of shares, the modeling of different classes of capital as call options on company’s enterprise value was analyzed and the values of different classes of shares were derived accordingly.

The Company also applied a discount for lack of marketability (“DLOM”), which was quantified by the black-Scholes option pricing model. Under this option-pricing method, which assumed that the put option is struck at the average price of the stock before the privately held shares can be sold, the cost of the put option was considered as a basis to determine the DLOM.

15.	SHARE-BASED COMPENSATION (Continued)

A summary of the stock option activity under the 2015 and 2018 Share Incentive Plan for the years ended December 31, 2016, 2017 and 2018 is included in the table below.

	Options granted			Weighted average
	Share Number			exercise price (US$)
Outstanding at January 1, 2016		4,740,000			0.06
Granted		1,860,000			0.24
Forfeited		(980,000	)		0.04
Outstanding at December 31, 2016		5,620,000			0.12
Granted		2,700,000			0.52
Forfeited		(780,000	)		0.27
Outstanding at December 31, 2017		7,540,000			0.25
Granted		6,130,000			0.64
Forfeited		(410,000	)		0.43
Outstanding at December 31, 2018		13,260,000			0.43

The following table summarizes information regarding the share options granted as of December 31, 2016, 2017 and 2018:

	As of December 31, 2016
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		5,620,000		0.12		9.22		1,854
Exercisable		915,000		0.02		8.83		366
Expected to vest		4,187,450		0.14		9.29		1,324

	As of December 31, 2017
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		7,540,000		0.25		8.65		3,697
Exercisable		2,612,500		0.06		7.99		987
Expected to vest		4,385,475		0.35		9.00		2,695

	As of December 31, 2018
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		13,260,000		0.43		8.40		18,705
Exercisable		3,945,000		0.08		7.03		1,752
Expected to vest		8,290,350		0.57		8.97		15,373

The weighted average grant date fair value of options granted for the years ended December 31, 2016, 2017 and 2018 was RMB2.50 (US$0.38), RMB6.01 (US$0.90) and RMB18.23 (US$2.66) per option, respectively.

No options were exercised for the years ended December 31, 2016, 2017 and 2018.

As of December 31, 2018, there was RMB53,879 of unrecognized compensation expenses related to the options.

15.	SHARE-BASED COMPENSATION (Continued)

(c)	Shares awarded to Mr. Chen

On August 23, 2018, the Company issued 4,000,000 Class A ordinary shares at par value to Mr. Chen’s wholly-owned entity Viomi Limited to award his contribution to the Company’s development. Such shares were immediately vested. The issuance of such shares is accounted for as a share-based compensation to Mr. Chen. The issuance date fair value was approximately US$3.30 per share.

Net (Loss) Income Per Share

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

NET (LOSS) INCOME PER SHARE

16.	NET (LOSS) INCOME PER SHARE

Basic net (loss) income per share is the amount of net (loss) income available to each share of ordinary shares outstanding during the reporting period. Diluted net (loss) income per share is the amount of net (loss) income available to each share of ordinary shares outstanding during the reporting period adjusted to include the effect of potentially dilutive ordinary shares.

For the years ended December 31, 2016, 2017 and 2018, the Group has determined that its convertible redeemable Class B Ordinary Shares, convertible redeemable Series A Preferred Shares and unvested Class A ordinary shares are participating securities as they participate in undistributed earnings on an as-if-converted basis. The holders of the Class B Ordinary Shares, Series A Preferred Shares and unvested Class A ordinary shares are entitled to receive dividends on a pro rata basis, as if their shares had been converted into ordinary shares. Accordingly, the Group uses the two-class method of computing net (loss) income per share, for ordinary shares and preferred shares according to the participation rights in undistributed earnings.

	Year ended December 31,
	2016			2017		2018
	RMB			RMB		RMB
Numerator:
Numerator for basic calculation - Net (loss) income attributable to ordinary shareholders of the Company		(3,453	)		8,033		50,544

Denominator:
Denominator for basic calculation - weighted average ordinary shares outstanding		12,230,136			20,684,681		71,771,033
Dilutive effect of share options		—			4,895,125		7,819,747
Denominator for diluted calculation		12,230,136			25,579,806		79,590,780

Basic net (loss) income per ordinary share		(0.28	)		0.39		0.70
Diluted net (loss) income per ordinary share		(0.28	)		0.31		0.64

For the years ended December 31, 2016, 2017 and 2018, the following shares outstanding were excluded from the calculation of diluted net (loss) income per ordinary share, as their inclusion would have been anti-dilutive for the periods prescribed.

	Year ended December 31,
	2016		2017		2018
Shares issuable upon exercise of share options		3,370,739		—		—
Shares issuable upon conversion of Restricted Shared owned the Founder		67,636,364		67,636,364		—
Shares issuable upon conversion of Class B Ordinary Shares owned by Red Better and Shunwei		67,636,364		67,636,364		—
Shares issuable upon conversion of Series A Preferred shares		18,181,818		18,181,818		—
Shares issuable upon exercise of unvested Restricted Shares owned by the Founder on behalf of certain key management founders		21,520,813		13,079,391		—

Related Party Transactions

12 Months Ended

Dec. 31, 2018

RELATED PARTY TRANSACTIONS

17.	RELATED PARTY TRANSACTIONS

Name		Relationship with the Group
Mr. Chen		Founder
Xiaomi Inc.		Controlled by Xiaomi
Xiaomi H.K.		Controlled by Xiaomi
Xiaomi Telecommunication Technology		Controlled by Xiaomi
Tianjin Jinxing		Controlled by Xiaomi
Beijing Xiaomi Software Co., Ltd (“Xiaomi Software”)		Controlled by Xiaomi
Guangzhou Xiaomi Information Service Co., Ltd (“Guangzhou Xiaomi”)		Controlled by Xiaomi

The Group’s relationship with Xiaomi

Xiaomi is The Group’s strategic partner and shareholder.

The Group’s sales to Xiaomi is governed by a business cooperation agreement, pursuant to which Xiaomi is responsible for the distribution and sales of such products through their network and sales channels.

The Group also sells products through Xiaomi’s online e-commerce channel Youpin.mi.com, and is charged of commissions pursuant to a commission sales agreement.

Transaction with Xiaomi

Business cooperation agreement

The current business corporation agreement entered into in 2017 with Xiaomi governs all the Group’s sales to Xiaomi. It will expire in August 2019, and will automatically extend for successive one-year period unless objected by a party at least 30 days prior to the expiration of the then current term.

Under the business cooperation agreement, (i) products sold to Xiaomi are exclusively designed for and can only be sold to Xiaomi, (ii) Xiaomi shall purchase these products at a price that covers all of the Group’s costs of raw materials, outsourcing manufacture, models, logistics and paid intellectual property licensing fees, in connection with the manufacture and delivery of these products, and (iii) Xiaomi and the Group shall share gross profits, derived from sales of these products, the retail prices of which were set by Xiaomi and the Group together.

Youpin commission sales agreement

The Group has entered into a commission sales agreement with Xiaomi for the sale of certain of the Group’s own branded products. The commission sales agreement will expire on December 31, 2018 and has been renewed up to December 31, 2019. Furthermore, this agreement may be terminated by Xiaomi with 30 days’ written notice.

Under the commission sales agreement, the Group shall pay a service fee, calculated as approximately 8% of the sales price excluding customers’ refunds or as otherwise agreed by the parties with respect to specific product lines, as well as a deposit to Xiaomi. The retail prices of the Group’s products on Youpin’s platform shall be no higher than the sales price from any other e-commerce merchants or the Group’s official offline sales channel, including in the event of sales or promotion.

17.	RELATED PARTY TRANSACTIONS (Continued)

(1)	Amount due from/to related parties

	As of December 31,
	2017		2018
	RMB		RMB
Accounts receivable from a relate party:
Xiaomi Telecommunication Technology^(a)		249,548		260,984

Other receivables from related parties:
Xiaomi Inc.^(c)		24,160		112,320
Xiaomi H.K.^(b)		33,448		—
Total		57,608		112,320

Amounts due to related parties:
Xiaomi Telecommunication Technology^(a)		1,225		3,876
Guangzhou Xiaomi		—		1,887
Xiaomi Software^(d)		32,228		—
Tianjin Jinxing^(e)		2,500		—
Total		35,953		5,763

(2)	Purchase from a related party

	Year ended December 31,
	2016		2017		2018
			RMB		RMB
Xiaomi Telecommunication Technology^(a)		1,327		1,685		18,235

(3)	Revenue from a related party

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi Telecommunication Technology^(a)		299,827		739,464		1,311,852

(4)	Selling and marketing expenses

	Year ended December 31,
	2016		2017		2018
			RMB		RMB
Xiaomi Inc.^(c)		166		3,327		20,824
Guangzhou Xiaomi		—		—		3,774
Total		166		3,327		24,598

(5)	Interest expenses

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi Software^(d)		1,761		1,761		440

17.	RELATED PARTY TRANSACTIONS (Continued)

(6)	Interest income

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi H.K.^(b)		272		490		107

(a)

The balance due from Xiaomi Telecommunication Technology represents receivable arising from sales of water purifier and accessories. The balance due to Xiaomi Telecommunication Technology represents payable arising from purchase of Xiaomi branded products and certain raw materials.

(b)

The balance due from Xiaomi H.K. represents loan and interest receivables from the related party. The loan is US$5,000 with an interest rate of 3 month Libor add 10bps. The loan term is 3 months and will be automatically extended by another 3 months if the two parties do not raise any objections on the maturity date. The loan has been settled in 2018.

(c)

Foshan Viomi sells its own brand products on the E-platform of Xiaomi Inc., which charges Foshan Viomi commission fee. The amount due from Xiaomi Inc. represents sales receivable net of commission fee.

(d)

The balance due to Xiaomi Software represents borrowing from the related party. The loan is RMB31,900 with an interest rate of 5.52% per annum. The loan term is 3 months and will be automatically extended by another 3 months if the two parties do not raise any objections on the maturity date. The loan has been settled in 2018.

(e)

The balance due to Tianjin Jinxing represents US$409 (equivalent to RMB2,671) that the Company received from Red Better with the understanding that RMB2,500 will be repaid to Tianjin Jinxing in the PRC. The balance was settled to Tianjin Jinxing in 2018.

Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

18.	FAIR VALUE MEASUREMENTS

Fair value reflects the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Group considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the assets or liabilities.

The Group applies a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. This guidance specifies a hierarchy of valuation techniques, which is based on whether the inputs into the valuation technique are observable or unobservable. The hierarchy is as follows:

Level 1—Valuation techniques in which all significant inputs are unadjusted quoted prices from active markets for assets or liabilities that are identical to the assets or liabilities being measured.

Level 2—Valuation techniques in which significant inputs include quoted prices from active markets for assets or liabilities that are similar to the assets or liabilities being measured and/or quoted prices for assets or liabilities that are identical or similar to the assets or liabilities being measured from markets that are not active. Also, model-derived valuations in which all significant inputs and significant value drivers are observable in active markets are Level 2 valuation techniques.

Level 3—Valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Unobservable inputs are valuation technique inputs that reflect the Group’s own assumptions about the assumptions that market participants would use in pricing an asset or liability.

18.	FAIR VALUE MEASUREMENTS (Continued)

The fair value guidance describes three main approaches to measure the fair value of assets and liabilities: (1) market approach; (2) income approach and (3) cost approach. The market approach uses prices and other relevant information generated from market transactions involving identical or comparable assets or liabilities. The income approach uses valuation techniques to convert future amounts to a single present value amount. The measurement is based on the value indicated by current market expectations about those future amounts. The cost approach is based on the amount that would currently be required to replace an asset.

When available, the Group uses quoted market prices to determine the fair value of an asset or liability. If quoted market prices are not available, the Group will measure fair value using valuation techniques that use, when possible, current market-based or independently sourced market parameters, such as interest rates and currency rates.

The Group did not have any other financial instruments that were required to be measured at fair value on a recurring basis as of December 31, 2017 and 2018 except for short-term investments (Note 6).

The following table summarizes the Group’s assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy as of December 31, 2018:

	Level 1		Level 2		Level 3		Total
Assets
Short-term investments (i)		—		168,993		—		168,993

(i) Short-term investments represent structured deposits and the Company values these short-term investments based on quoted prices of similar products provided by banks at the end of each period, and accordingly, the Company classifies the valuation techniques that use these inputs as Level 2.

Apart from the short-term investments, the Company’s other financial instruments consist principally of cash and cash equivalents, restricted cash, accounts receivable, other receivables, amounts due to/from related parties, accounts payable and certain accrued expenses. The recorded values of cash and cash equivalents, restricted cash, accounts receivable, other receivables, amounts due to/from related parties, accounts payable and certain accrued expenses are recorded at cost which approximates fair value.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

19.	COMMITMENTS AND CONTINGENCIES

(a)	Lease commitments

The Group leases its offices and an offline store under non-cancelable operating lease agreements. The Group recognizes rental expense under such arrangements on a straight-line basis over the lease term.

As of December 31, 2018, future minimum commitments under non-cancelable agreements were as follows:

	Rental
	RMB
2019		4,284
2020		2,947
2021		1,600
2022 and after		978
		9,809

(b)	Capital and other commitment

The Group entered into an agreement with a third party on July 4, 2018, pursuant to which the Group and the third party agreed to set up a company primarily engaged in manufacturing of the Group’s certain existing products. Under the agreement, the Group’s committed investment amount as of December 31, 2018 was RMB6,000. The Group has paid the investment amount of RMB6,000 in March 2019.

(c)	Legal proceedings

From time to time, the Group is involved in claims and legal proceedings that arise in the ordinary course of business. Based on currently available information, management does not believe that the ultimate outcome of these unresolved matters, individually and in the aggregate, is likely to have a material adverse effect on the Group’s financial position, results of operations or cash flows.

19.	COMMITMENTS AND CONTINGENCIES (Continued)

However, litigation is subject to inherent uncertainties and the Group’s view of these matters may change in the future. If an unfavorable outcome were to occur, there exists the possibility of a material adverse impact on the Group’s financial position and results of operations for the periods in which the unfavorable outcome occurs.

Subsequent Events

12 Months Ended

Dec. 31, 2018

Subsequent Events [Abstract]

SUBSEQUENT EVENTS

20.	SUBSEQUENT EVENTS

On March 18, 2019, the Board of Director approved a special cash dividend of US$0.0333 per ordinary share on its outstanding shares to shareholders of record as of the close of trading on March 28, 2019.

Holders of ADSs, each representing three ordinary shares of the Company, are accordingly entitled to a cash dividend of US$0.10 per ADS.

Restricted Net Assets

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Restricted Net Assets

21.	RESTRICTED NET ASSETS

Relevant PRC laws and regulations permit payments of dividends by the Group’s entities incorporated in the PRC only out of their retained earnings, if any, as determined in accordance with PRC accounting standards and regulations. In addition, the Company’s entities in the PRC are required to annually appropriate 10% of their net after-tax income to the statutory general reserve fund prior to payment of any dividends, unless such reserve funds have reached 50% of their respective registered capital. As a result of these and other restrictions under PRC laws and regulations, the Company’s entities incorporated in the PRC are restricted in their ability to transfer a portion of their net assets to the Company either in the form of dividends, loans or advances, which restricted portion as calculated under U.S. GAAP amounted to RMB18,750 and RMB13,750 as of December 31, 2017 and 2018. There are no differences between U.S. GAAP and PRC accounting standards in connection with the reported net assets of the legally owned subsidiaries in the PRC and the VIE. Even though the Company currently does not require any such dividends, loans or advances from the PRC entities for working capital and other funding purposes, the Company may in the future require additional cash resources from them due to changes in business conditions, to fund future acquisitions and development, or merely to declare and pay dividends or distributions to its shareholders. Except for the above, there is no other restriction on use of proceeds generated by the Group’s subsidiaries and VIE to satisfy any obligations of the Company.

For the year ended December 31, 2018, the Company performed a test on the restricted net assets of subsidiaries and VIE in accordance with Securities and Exchange Commission Regulation S-X Rule 4-08 (e) (3), “General Notes to Financial Statements” and concluded that the restricted net assets do not exceed 25% of the consolidated net assets of the Company as of December 31, 2018 and the condensed financial information of the Company are not required to be presented.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of presentation

(a)	Basis of presentation

Consolidation

(b)	Consolidation

Use of estimates

(c)	Use of estimates

Foreign currency translation

(d)	Foreign currency translation

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

Convenience Translation

(e)	Convenience Translation

Cash and cash equivalents

(f)	Cash and cash equivalents

Readily convertible to known amounts of cash throughout the maturity period;

ii)

So near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Restricted cash

(g)	Restricted cash

Short-term investments

(h)	Short-term investments

Accounts receivable

(i)	Accounts receivable

Inventories

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(j)	Inventories

Property, plant and equipment, net

(k)	Property, plant and equipment, net

	Estimated useful lives	Residual rate
Computers and equipment	2-3 years	0%-5%
Vehicle	4 years	5%

Intangible assets

(l)	Intangible assets

				Estimated useful lives
Software				5 years

Leases

(m)

Leases

The Group has no capital leases for any of the years presented.

Mezzanine equity

(n)	Mezzanine equity

Revenue recognition

(o)	Revenue recognition

1)	The Group conducts its business through various contractual arrangements, the following table disaggregates the Group’s revenue by type of contract for the years ended December 31, 2016, 2017 and 2018:

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Sales to Xiaomi		299,827		739,464		1,311,852
—Xiaomi-branded products		280,501		654,950		1,175,332
—Viomi-branded products		19,326		84,514		136,520
Sales to third-party customers		12,747		133,755		1,249,377
		312,574		873,219		2,561,229

Sales to Xiaomi’s affiliate Xiaomi Telecommunication Technology Co., Ltd. (“Xiaomi Telecommunication Technology”)

The Group generated a substantial portion of its revenues from sales of products to Xiaomi.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

- Sales to leading e-commerce platforms and offline experience stores

- Sales to customers directly through the online platforms operated by Xiaomi, third parties and the Group

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

2)	Sales returns and sales incentives

- Sales to leading e-commerce platforms

- Sales to Xiaomi and offline experience stores

- 7 days unconditional sales return

Warranty

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

4)	Value added taxes

5)	Contract balances

Cost of revenues

(p)	Cost of revenues

Research and development expenses

(q)	Research and development expenses

Selling and marketing expenses

(r)	Selling and marketing expenses

General and administrative expenses

(s)	General and administrative expenses

Government subsidies

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(t)	Government subsidies

Employee benefits

(u)	Employee benefits

PRC Contribution Plan

Share-based compensation

(v)	Share-based compensation

Upon the completion of the IPO on September 25, 2018, all Class B Ordinary Shares were converted into Post-IPO Class B Ordinary Shares, the liability award had been settled.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

Income taxes

(w)	Income taxes

Uncertain tax positions

Comprehensive (loss) income

(x)	Comprehensive (loss) income

Statutory reserves

(y)	Statutory reserves

The Company's subsidiaries and VIEs established in the PRC are required to make appropriations to certain non-distributable reserve funds.

2.	SIGNIFICANT ACCOUNTING POLICIES (Continued)

(Loss) Income per share

(z)	(Loss) Income per share

Related parties

(aa)	Related parties

Segment reporting

(bb)	Segment reporting

Newly issued accounting pronouncements

(cc)	Newly issued accounting pronouncements

Organization and Principal Activities (Tables)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Principal Subsidiaries and VIEs

As of December 31, 2018, details of the Company’s principal subsidiaries and VIEs were as follows:

	Place of incorporation	Date of incorporation	Percentage of beneficial ownership	Principal activities
Subsidiaries:
Viomi HK	Hong Kong	January 30, 2015	100%	Investment holding
Lequan	PRC	May 15, 2015	100%	Investment holding
VIEs:
Foshan Viomi	PRC	May 6, 2014	100%	Home appliance development and sales
Beijing Viomi	PRC	January 12, 2015	100%	No substantial business
Subsidiaries of Foshan Viomi:
Guangdong Lizi Technology Co., Ltd. (“Guangdong Lizi”)	PRC	July 26, 2018	VIE’s subsidiary	Home appliance development and sales

Schedule of Financial Statement Amounts and Balances of VIEs

	As of December 31,
	2017		2018
	RMB		RMB
Cash and cash equivalents		210,280		401,424
Restricted cash		—		29,550
Short-term investments		—		168,993
Accounts receivable from third parties (net of allowance of nil and nil as of December 31, 2017and 2018, respectively)		4,348		111,718
Accounts receivable from a related party (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)		249,548		260,984
Other receivable from related parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)		24,160		112,320
Inventories		50,692		231,975
Prepaid expenses and other current assets		22,986		46,499
Total current assets		562,014		1,363,463
Property, plant and equipment, net		3,086		11,301
Deferred tax assets		3,048		5,234
Intangible assets, net		—		169
Prepaid expenses and other non-current assets		—		3,636
Total non-current assets		6,134		20,340
Total assets		568,148		1,383,803
Accounts and notes payable		291,643		548,481
Advances from customers		27,015		86,312
Amounts due to related parties		35,953		5,763
Accrued expenses and other liabilities		60,953		179,712
Income tax payables		11,612		10,199
Total current liabilities		427,176		830,467
Accrued expenses and other liabilities		460		518
Total non-current liabilities		460		518
Total liabilities		427,636		830,985

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES (Continued)

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Revenue		312,523			873,083			2,561,229
Net income		16,295			92,159			70,232

Net cash provided by operating activities		13,146			123,182			209,690
Net cash used in investing activities		(1,609	)		(1,234	)		(183,262	)
Net cash provided by (used in) financing activities		12,999			—			(37,731	)

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of Property Plant and Equipment Estimated Useful Lives and Residual Rate

	Estimated useful lives	Residual rate
Computers and equipment	2-3 years	0%-5%
Vehicle	4 years	5%

Schedule of Amortization of Finite-Lived Intangible Assets Estimated Useful Lives

Amortization of finite-lived intangible assets is computed using the straight-line method over their estimated useful lives, which are as follows:

				Estimated useful lives
Software				5 years

Schedule of Disaggregation of Revenue by Type of Contract

the following table disaggregates the Group’s revenue by type of contract for the years ended December 31, 2016, 2017 and 2018:

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Sales to Xiaomi		299,827		739,464		1,311,852
—Xiaomi-branded products		280,501		654,950		1,175,332
—Viomi-branded products		19,326		84,514		136,520
Sales to third-party customers		12,747		133,755		1,249,377
		312,574		873,219		2,561,229

Concentration and Risks (Tables)

12 Months Ended

Dec. 31, 2018

Credit Risk

Concentration Risk [Line Items]

Summary of Concentration of Risk

Accounts receivable from third-parties concentration of credit risk as below:

	As of December 31,
	2017					2018
	RMB					RMB
Company A	—		—				58,766		53	%
Company B	—		—				36,734		33	%
Company C		2,778		64	%	*		*

Less than 10%

Other receivables from related parties concentration of credit risk as below:

	As of December 31,
	2017				2018
	RMB				RMB
Xiaomi Inc.		24,160	42	%		112,320	100	%
Xiaomi H.K. Limited (“Xiaomi H.K.”)		33,448	58	%		—	—

Revenue Concentration Risk

Concentration Risk [Line Items]

Summary of Concentration of Risk

	Year ended December 31,
	2016				2017				2018
	RMB				RMB				RMB
Xiaomi Telecommunication Technology		299,827	96	%		739,464	85	%		1,311,852	51	%

Cash and Cash Equivalents (Tables)

12 Months Ended

Dec. 31, 2018

Cash And Cash Equivalents [Abstract]

Summary of Cash and Cash Equivalents Balance

	As of December 31, 2017				As of December 31, 2018
			RMB				RMB
	Amount		equivalent		Amount		equivalent
US$		11,163		73,001		88,529		607,596
RMB		206,951		206,951		332,702		332,702
Total				279,952				940,298

Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2018

Schedule Of Investments [Abstract]

Schedule of Short-Term Investments Balance

Short-term investments balance as of December 31, 2018 is primarily denominated in the following currencies:

	As of December 31, 2017				As of December 31, 2018
			RMB				RMB
	Amount		equivalent		Amount		equivalent
RMB		—		—		100,022		100,022
US$		—		—		10,049		68,971
Total				—				168,993

Inventories (Tables)

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories consisted of the followings:

	As of December 31,
	2017		2018
	RMB		RMB
Finished goods		13,956		136,494
Raw materials		36,736		95,481
Inventories		50,692		231,975

Prepaid Expenses and Other Assets (Tables)

12 Months Ended

Dec. 31, 2018

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Schedule of Prepaid Expenses and Other Assets

	As of December 31,
	2017		2018
	RMB		RMB
Advances to suppliers		14,428		23,549
Other receivables		3,054		15,361
Prepayment for equipment		—		3,636
Other current assets		5,525		7,745
Rental deposits		276		235
Total		23,283		50,526
Less: non-current portion		—		(3,636	)
Prepaid expenses and other assets-current portion		23,283		46,890

Property, Plant and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

Schedule of Property, Plant and Equipment, Net

Property, plant and equipment, net consisted of the following:

	As of December 31,
	2017			2018
	RMB			RMB
Computers and equipment		5,815			16,270
Vehicle		508			508
Total		6,323			16,778
Less: accumulated depreciation		(3,237	)		(5,477	)
Property, plant and equipment, net		3,086			11,301

Accrued Expenses and Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2018

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Liabilities

	As of December 31,
	2017			2018
	RMB			RMB
Freight payable		9,799			50,680
Other tax payable		15,359			42,076
Accrued payroll and welfare		16,304			39,700
Product warranty		13,909			12,744
Marketing and promotion expenses		1,000			10,710
Professional fee payables		—			10,340
Installation fee payables		—			8,133
Deferred revenue		146			1,276
Deposits received related to unvested shares		496			—
Other current liabilities		4,871			25,789
Total		61,884			201,448
Less: non-current portion		(460	)		(518	)
Accrued expenses and other liabilities-current portion		61,424			200,930

Schedule of Product Warranty Activities

Product warranty activities were as follows:

	Product Warranty
	RMB
Balance at December 31, 2016		2,483
Provided during the year		17,806
Utilized during the year		(6,380	)
Balance at December 31, 2017		13,909
Provided during the year		19,775
Utilized during the year		(20,940	)
Balance at December 31, 2018		12,744

Revenue (Tables)

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Schedule of Revenue

	Year ended December 31, 2016
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		273,282		206,679		66,603
Smart water purification systems		250,442		191,848		58,594
Other smart products		22,840		14,831		8,009
- Consumable products		19,376		10,644		8,732
- Other products		19,859		15,166		4,693
Total of sales of product		312,517		232,489		80,028
Rendering of services
- Installation services		57		55		2
Total		312,574		232,544		80,030

	Year ended December 31, 2017
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		712,317		499,739		212,578
Smart water purification systems		570,784		399,788		170,996
Smart kitchen products		50,656		34,987		15,669
Other smart products		90,877		64,964		25,913
- Consumable products		87,500		48,123		39,377
- Other products		72,686		49,489		23,197
Total of sales of product		872,503		597,351		275,152
Rendering of services
- Installation services		716		685		31
Total		873,219		598,036		275,183

	Year ended December 31, 2018
	Revenues		Cost of revenues		Gross profit
	RMB		RMB		RMB
Sales of product
- IoT-enabled smart home products		2,081,273		1,514,344		566,929
Smart water purification systems		930,178		614,829		315,349
Smart kitchen products		744,990		596,005		148,985
Other smart products		406,105		303,510		102,595
- Consumable products		141,940		67,433		74,507
- Other products		323,381		247,717		75,664
Total of sales of product		2,546,594		1,829,494		717,100
Rendering of services
- Installation services		14,635		13,938		697
Total		2,561,229		1,843,432		717,797

Income Tax (Benefits) Expenses (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Current and Deferred Components of Income Taxes

The current and deferred components of income taxes appearing in the consolidated statements of comprehensive (loss) income are as follows:

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Current tax expenses		—			15,519			26,247
Deferred tax benefit		(2,247	)		(801	)		(2,186	)
Income tax (benefits) expenses		(2,247	)		14,718			24,061

Reconciliation between Income Tax Expenses Computed by Applying PRC Enterprise Tax Rate Before Income Taxes and Actual Provision

12.	INCOME TAX (BENEFITS) EXPENSES (Continued)

Reconciliation between the income tax expenses computed by applying the PRC enterprise tax rate to income before income taxes and actual provision were as follows:

	Year ended December 31,
	2016			2017			2018
	RMB			RMB			RMB
Income from operations in the PRC		13,546			106,868			93,910
Income (loss) from overseas entities		466			1,090			(4,499	)
Income before income tax		14,012			107,958			89,411

Tax expense at PRC enterprise income tax rate of 25%		3,503			26,990			22,353
Income tax on tax holiday⁽¹⁾		(1,414	)		(10,989	)		(9,632	)
Tax effect of permanence differences⁽²⁾		(1,187	)		(2,640	)		(7,871	)
Effect of income tax rate change⁽³⁾		3,179			—			—
Change in valuation allowance⁽⁴⁾		(7,756	)		760			602
Effect of share-based compensation		1,587			873			17,492
Effect of income tax in jurisdictions other than the PRC		(159	)		(276	)		1,117
Income tax (benefits) expenses		(2,247	)		14,718			24,061

(1)

(2)

The permanent book-tax differences mainly consisted of R&D super deductions.

(3)

Effect of income tax rate change represents the effect due to the change in the applicable tax rate in calculating deferred income tax as a result of Foshan Viomi’s qualification of HNTE in 2016.

(4)

Per Share Effect of Tax Holidays

The per share effect of the tax holidays are as follows:

	Year ended December 31,
	2016	2017	2018
	RMB	RMB	RMB
Net income per share effect – basic	0.12	0.53		0.22
Net income per share effect – diluted	0.12	0.41		0.20

Significant Components of Deferred Tax Assets

The significant components of the Group’s deferred tax assets were as follows:

	As of December 31,
	2017			2018
	RMB			RMB
Inventory write downs		541			421
Accrued expenses and others		2,485			4,616
Deferred income		22			191
Net operating loss carry forwards		952			1,560
Total deferred tax assets		4,000			6,788
Less: valuation allowance		(952	)		(1,554	)
Deferred tax assets, net		3,048			5,234

Movement of Valuation Allowance

Movement of valuation allowance

	Year ended December 31,
	2016			2017		2018
	RMB			RMB		RMB
Balance at beginning of the year		7,948			192		952
Provided		190			760		602
Reversals		(7,946	)		—		—
Balance at end of the year		192			952		1,554

Redeemable Convertible Preferred and Class B Ordinary Shares (Tables)

12 Months Ended

Dec. 31, 2018

Temporary Equity Disclosure [Abstract]

Summary of Change Balance of Series A Preferred Shares and Class B Ordinary Shares

The change in the balance of Series A Preferred Shares and Class B Ordinary Shares included in mezzanine equity for the years ended December 31, 2016, 2017 and 2018 are as follows:

	Series A Preferred Shares			Class B Ordinary Shares held by the Founder⁽¹⁾⁽²⁾			Class B Ordinary Shares- owned by Xiaomi⁽¹⁾			Total
	RMB			RMB			RMB			RMB
Balance as of January 1, 2016		133,573			51,057			204,230			388,860
Accretion of preferred shares		8,221			—			—			8,221
Foreign exchange		9,485			3,488			13,945			26,918
Balance as of December 31, 2016		151,279			54,545			218,175			423,999
Accretion of preferred shares		8,834			—			—			8,834
Foreign exchange		(9,068	)		(3,169	)		(12,668	)		(24,905	)
Balance as of December 31, 2017		151,045			51,376			205,507			407,928
Accretion of preferred shares		6,563			—			—			6,563
Foreign exchange		7,487			2,437			9,743			19,667
Conversion of Series A Preferred Shares and Class B Ordinary Shares to ordinary shares upon the completion of the IPO on September 25, 2018		(165,095	)		(53,813	)		(215,250	)		(434,158	)
Balance as of December 31, 2018		—			—			—			—

(1)

(2)

Out of the 67,636,364 Class B Ordinary Shares held by the Founder, 50,727,273 Class B ordinary shares held by the Founder pursuant to the restricted share arrangement is included in liability award.

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Compensation Expense Recognized for Share-Based Awards

Compensation expense recognized for share-based awards was as follows:

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Share-based compensation expenses
—Restricted shares owned by the Founder – equity component^(a)		6,051		2,670		826
—Restricted shares owned by the Founder – liability component^(a)		266		286		212
—Restricted shares owned by the Founder on behalf of certain key management founders^(a)		93		48		14
—Share options^(b)		4,168		2,817		25,391
—Shares awarded to Mr. Chen^(c)		—		—		90,168
Total share-based compensation expenses		10,578		5,821		116,611

Summary of Restricted Shares Activity

A summary of the Restricted Shares activity for the years ended December 31, 2016, 2017 and 2018 is presented below:

	Number of shares
	Restricted Shares held by the Founder on behalf of certain key management founders			Restricted Shares held by the Founder on his own behalf			Total
Outstanding at January 1, 2016		25,363,638			50,727,273			76,090,911
Vested		(8,454,546	)		(16,909,091	)		(25,363,637	)
Outstanding at December 31, 2016		16,909,092			33,818,182			50,727,274
Vested		(8,454,546	)		(16,909,091	)		(25,363,637	)
Outstanding at December 31, 2017		8,454,546			16,909,091			25,363,637
Surrender and cancellation⁽¹⁾		(5,918,182	)		—			(5,918,182	)
Vested		(2,536,364	)		(16,909,091	)		(19,445,455	)
Outstanding at December 31, 2018		—			—			—

(1)

Schedule of Movement of Liability Awards with Respect to Unsettled Restricted Shares Granted

15.	SHARE-BASED COMPENSATION (Continued)

	Liability-classified Awards (RMB)
	Restricted Shares held by the Founder on his own behalf
Balance as at January 1, 2016		4,181
Share-based compensation expenses		266
Foreign currency translation adjustment		103
Balance as at December 31, 2016		4,550
Share-based compensation expenses		286
Foreign currency translation adjustment		(98	)
Outstanding at December 31, 2017		4,738
Share-based compensation expenses		212
Foreign currency translation adjustment		408
Conversion of Restricted Shares to ordinary shares upon the completion of the IPO on September 25, 2018		(5,358	)
Outstanding at December 31, 2018		—

Assumptions used to Determine Fair Value of Share Options Granted

Assumptions used to determine the fair value of share options granted during 2016, 2017 and 2018 are summarized in the following table:

	Year ended December 31,
	2016			2017		2018
Risk-free interest rate		2.86	%	3.06%-3.89%		3.62%~3.92%
Expected volatility	50.14%-50.15%			47.02%-49.44%		45.51%~46.99%
Expected life of option (years)	10			10			10
Expected dividend yield		—			—		—
Fair value per ordinary share	US$0.51			US$0.76-US$ 1.59		US$1.61-US$3.30

Summary of Stock Option Activity

15.	SHARE-BASED COMPENSATION (Continued)

A summary of the stock option activity under the 2015 and 2018 Share Incentive Plan for the years ended December 31, 2016, 2017 and 2018 is included in the table below.

	Options granted			Weighted average
	Share Number			exercise price (US$)
Outstanding at January 1, 2016		4,740,000			0.06
Granted		1,860,000			0.24
Forfeited		(980,000	)		0.04
Outstanding at December 31, 2016		5,620,000			0.12
Granted		2,700,000			0.52
Forfeited		(780,000	)		0.27
Outstanding at December 31, 2017		7,540,000			0.25
Granted		6,130,000			0.64
Forfeited		(410,000	)		0.43
Outstanding at December 31, 2018		13,260,000			0.43

Summary Regarding Share Options Granted

The following table summarizes information regarding the share options granted as of December 31, 2016, 2017 and 2018:

	As of December 31, 2016
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		5,620,000		0.12		9.22		1,854
Exercisable		915,000		0.02		8.83		366
Expected to vest		4,187,450		0.14		9.29		1,324

	As of December 31, 2017
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		7,540,000		0.25		8.65		3,697
Exercisable		2,612,500		0.06		7.99		987
Expected to vest		4,385,475		0.35		9.00		2,695

	As of December 31, 2018
			Weighted- average exercise		Weighted- average remaining exercise contractual		Aggregate
	Options Number		price per option		life (years)		intrinsic value
			US$				US$
Options
Outstanding		13,260,000		0.43		8.40		18,705
Exercisable		3,945,000		0.08		7.03		1,752
Expected to vest		8,290,350		0.57		8.97		15,373

Net (Loss) Income Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Net (Loss) Income Per Share, Basic and Diluted

Accordingly, the Group uses the two-class method of computing net (loss) income per share, for ordinary shares and preferred shares according to the participation rights in undistributed earnings.

	Year ended December 31,
	2016			2017		2018
	RMB			RMB		RMB
Numerator:
Numerator for basic calculation - Net (loss) income attributable to ordinary shareholders of the Company		(3,453	)		8,033		50,544

Denominator:
Denominator for basic calculation - weighted average ordinary shares outstanding		12,230,136			20,684,681		71,771,033
Dilutive effect of share options		—			4,895,125		7,819,747
Denominator for diluted calculation		12,230,136			25,579,806		79,590,780

Basic net (loss) income per ordinary share		(0.28	)		0.39		0.70
Diluted net (loss) income per ordinary share		(0.28	)		0.31		0.64

Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share

	Year ended December 31,
	2016		2017		2018
Shares issuable upon exercise of share options		3,370,739		—		—
Shares issuable upon conversion of Restricted Shared owned the Founder		67,636,364		67,636,364		—
Shares issuable upon conversion of Class B Ordinary Shares owned by Red Better and Shunwei		67,636,364		67,636,364		—
Shares issuable upon conversion of Series A Preferred shares		18,181,818		18,181,818		—
Shares issuable upon exercise of unvested Restricted Shares owned by the Founder on behalf of certain key management founders		21,520,813		13,079,391		—

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2018

Name		Relationship with the Group
Mr. Chen		Founder
Xiaomi Inc.		Controlled by Xiaomi
Xiaomi H.K.		Controlled by Xiaomi
Xiaomi Telecommunication Technology		Controlled by Xiaomi
Tianjin Jinxing		Controlled by Xiaomi
Beijing Xiaomi Software Co., Ltd (“Xiaomi Software”)		Controlled by Xiaomi
Guangzhou Xiaomi Information Service Co., Ltd (“Guangzhou Xiaomi”)		Controlled by Xiaomi

Schedule of Related Party Transactions

17.	RELATED PARTY TRANSACTIONS (Continued)

(1)	Amount due from/to related parties

	As of December 31,
	2017		2018
	RMB		RMB
Accounts receivable from a relate party:
Xiaomi Telecommunication Technology^(a)		249,548		260,984

Other receivables from related parties:
Xiaomi Inc.^(c)		24,160		112,320
Xiaomi H.K.^(b)		33,448		—
Total		57,608		112,320

Amounts due to related parties:
Xiaomi Telecommunication Technology^(a)		1,225		3,876
Guangzhou Xiaomi		—		1,887
Xiaomi Software^(d)		32,228		—
Tianjin Jinxing^(e)		2,500		—
Total		35,953		5,763

(2)	Purchase from a related party

	Year ended December 31,
	2016		2017		2018
			RMB		RMB
Xiaomi Telecommunication Technology^(a)		1,327		1,685		18,235

(3)	Revenue from a related party

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi Telecommunication Technology^(a)		299,827		739,464		1,311,852

(4)	Selling and marketing expenses

	Year ended December 31,
	2016		2017		2018
			RMB		RMB
Xiaomi Inc.^(c)		166		3,327		20,824
Guangzhou Xiaomi		—		—		3,774
Total		166		3,327		24,598

(5)	Interest expenses

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi Software^(d)		1,761		1,761		440

17.	RELATED PARTY TRANSACTIONS (Continued)

(6)	Interest income

	Year ended December 31,
	2016		2017		2018
	RMB		RMB		RMB
Xiaomi H.K.^(b)		272		490		107

(a)

(b)

(c)

(d)

(e)

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Summary of Assets Measured at Fair Value on Recurring Basis

The following table summarizes the Group’s assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy as of December 31, 2018:

	Level 1		Level 2		Level 3		Total
Assets
Short-term investments (i)		—		168,993		—		168,993

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Commitments under Non-Cancellable Agreements

As of December 31, 2018, future minimum commitments under non-cancelable agreements were as follows:

	Rental
	RMB
2019		4,284
2020		2,947
2021		1,600
2022 and after		978
		9,809

Organization and Principal Activities - Additional Information (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands			1 Months Ended	7 Months Ended	12 Months Ended
	Sep. 25, 2018 $ / shares shares	Aug. 23, 2018 USD ($) $ / shares shares	Jul. 31, 2015 CNY (¥) shares	Jul. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($) $ / shares shares	Aug. 22, 2018 $ / shares shares	Jun. 30, 2018 shares	Dec. 31, 2017 shares	May 31, 2014 CNY (¥)
Organization And Principal Activities [Line Items]
Entity incorporated state					Cayman Islands	Cayman Islands
Entity incorporation date					2015-01	2015-01
Ordinary shares issued in exchange of interest, value \| ¥					¥ 633,508
Common stock, par value per share \| $ / shares		$ 0.00001					$ 0.0001
Preferred shares, par value \| $ / shares		$ 0.00001					0.0001
Stock split ratio		10
Surrender of outstanding shares after share split		0.90
Stock, conversion basis					IPO, 16,145,454 issued class A ordinary shares held by certain key management founders, 33,818,182 issued Class B Ordinary Shares held by Red Better, and 67,636,364 issued Class B Ordinary Shares held by Mr. Chen’s wholly-owned entity Viomi Limited was automatically converted by way of re-designation and re-classification into Post-IPO Class B Ordinary Shares on a one-for-one basis, and the rest of the outstanding class A ordinary shares, the rest of the outstanding class B Ordinary Shares, and all outstanding Series A Preferred Shares was automatically converted by way of re-designation and re-classification into Post-IPO Class A Ordinary Shares on a one-for-one basis.	IPO, 16,145,454 issued class A ordinary shares held by certain key management founders, 33,818,182 issued Class B Ordinary Shares held by Red Better, and 67,636,364 issued Class B Ordinary Shares held by Mr. Chen’s wholly-owned entity Viomi Limited was automatically converted by way of re-designation and re-classification into Post-IPO Class B Ordinary Shares on a one-for-one basis, and the rest of the outstanding class A ordinary shares, the rest of the outstanding class B Ordinary Shares, and all outstanding Series A Preferred Shares was automatically converted by way of re-designation and re-classification into Post-IPO Class A Ordinary Shares on a one-for-one basis.
Foshan Viomi and Beijing Viomi
Organization And Principal Activities [Line Items]
Percentage of beneficial ownership						100.00%
Class A Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued		4,000,000						33,818,182	33,818,182
Ordinary shares, transferred								16,145,454
Ordinary shares, surrendered								17,672,728
Common stock, par value per share \| $ / shares						$ 0.00001	$ 0.0001
Ordinary shares, shares authorized							346,545,454
Series A Preferred Shares
Organization And Principal Activities [Line Items]
Stock issued						0			18,181,818
IPO
Organization And Principal Activities [Line Items]
Shares issued	34,200,000
IPO \| American Depositary Shares
Organization And Principal Activities [Line Items]
Shares issued	11,400,000
Shares issued price per share \| $ / shares	$ 9.00
Post-IPO
Organization And Principal Activities [Line Items]
Ordinary shares, shares authorized		5,000,000,000
Ordinary shares, Value of shares authorized \| $		$ 50,000
Conversion ratio of Class B Ordinary Share into Post-IPO Class A ordinary shares		1
Stock, conversion basis					Each Post-IPO Class B Ordinary Share is convertible into one Post-IPO Class A Ordinary Share at any time by the holder thereof.	Each Post-IPO Class B Ordinary Share is convertible into one Post-IPO Class A Ordinary Share at any time by the holder thereof.
Post-IPO \| Class A Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						90,200,000
Common stock, par value per share \| $ / shares	$ 0.00001	$ 0.00001				$ 0.00001
Ordinary shares, shares authorized	4,800,000,000	4,800,000,000				4,800,000,000
Ordinary shares, voting rights		1
Post-IPO \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						117,600,000
Common stock, par value per share \| $ / shares	$ 0.00001	$ 0.00001				$ 0.00001
Ordinary shares, shares authorized	150,000,000	150,000,000				150,000,000
Ordinary shares, voting rights		10
Post-IPO \| Designated Common Stock
Organization And Principal Activities [Line Items]
Common stock, par value per share \| $ / shares	$ 0.00001
Ordinary shares, shares authorized	50,000,000
Foshan Viomi
Organization And Principal Activities [Line Items]
Change in basis of assets and liabilities \| $						$ 0
Mr. Chen
Organization And Principal Activities [Line Items]
Equity investments amount \| ¥										¥ 7,500
Initial equity interest percent										60.00%
Mr. Chen \| Class A Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued		4,000,000
Tianjin Jinxing
Organization And Principal Activities [Line Items]
Equity investments amount \| ¥										¥ 5,000
Initial equity interest percent										40.00%
Key Management Founders
Organization And Principal Activities [Line Items]
Equity investments amount \| ¥										¥ 2,500
Key Management Founders \| Post-IPO \| Class A Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						16,145,454
Red Better Limited \| Key Management Founders \| Class A Ordinary Shares
Organization And Principal Activities [Line Items]
Shares issued			33,818,182
Ordinary shares issued in exchange of interest, value \| ¥			¥ 2,500
Red Better Limited \| Mr. Chen \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Shares issued			67,636,364
Ordinary shares issued in exchange of interest, value \| ¥			¥ 5,000
Red Better Limited \| IPO \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						33,818,182
Red Better Limited \| Post-IPO \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						33,818,182
Viomi Limited \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Shares issued			67,636,364
Ordinary shares issued in exchange of interest, value \| ¥			¥ 5,000
Viomi Limited \| IPO \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						67,636,364
Viomi Limited \| Post-IPO \| Class B Ordinary Shares
Organization And Principal Activities [Line Items]
Ordinary shares, issued						67,636,364
Investors \| Series A Preferred Shares
Organization And Principal Activities [Line Items]
Stock issued				18,181,818
Shares issued price per share \| $ / shares				$ 1.1
Stock issued for consideration including conversion of outstanding bridge loans \| $				$ 20,000
Outstanding bridge loans \| $				$ 5,250

Organization and Principal Activities - Schedule of Principal Subsidiaries and VIEs (Details)	12 Months Ended
	Dec. 31, 2018
Organization And Principal Activities [Line Items]
Place of incorporation	Cayman Islands
Foshan Viomi \| VIEs
Organization And Principal Activities [Line Items]
Place of incorporation	PRC
Date of incorporation	May 06, 2014
Percentage of beneficial ownership	100.00%
Principal activities	Home appliance development and sales
Beijing Viomi \| VIEs
Organization And Principal Activities [Line Items]
Place of incorporation	PRC
Date of incorporation	Jan. 12, 2015
Percentage of beneficial ownership	100.00%
Principal activities	No substantial business
Guangdong Lizi Technology Co Ltd Gangdong Lizi
Organization And Principal Activities [Line Items]
Place of incorporation	PRC
Date of incorporation	Jul. 26, 2018
Percentage of beneficial ownership	VIE’s subsidiary
Principal activities	Home appliance development and sales
Subsidiaries \| Viomi HK
Organization And Principal Activities [Line Items]
Place of incorporation	Hong Kong
Date of incorporation	Jan. 30, 2015
Percentage of beneficial ownership	100.00%
Principal activities	Investment holding
Subsidiaries \| Lequan
Organization And Principal Activities [Line Items]
Place of incorporation	PRC
Date of incorporation	May 15, 2015
Percentage of beneficial ownership	100.00%
Principal activities	Investment holding

Organization and Principal Activities - Assets and Liabilities of VIEs and its Subsidiaries and Group's taken as Whole (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Variable Interest Entity [Line Items]
Cash and cash equivalents	¥ 940,298	$ 136,761	¥ 279,952	$ 40,718	¥ 156,930	¥ 127,128
Restricted cash	29,550	4,298	0
Short-term investments	168,993	24,579	0
Accounts receivable from third parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	111,718	16,249	4,348
Other receivables from related parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	112,320	16,336	57,608
Inventories	231,975	33,739	50,692
Prepaid expenses and other current assets	46,890	6,819	23,283
Total current assets	1,902,728	276,740	665,431
Property, plant and equipment, net	11,301	1,644	3,086
Intangible assets, net	169	25	0
Prepaid expenses and other non-current assets	3,636	529	0
Total non-current assets	20,340	2,959	6,134
Total assets	1,923,068	279,699	671,565
Accounts and notes payable current	548,481	79,773	291,643
Advances from customers	86,312	12,554	27,015
Amounts due to related parties	5,763	838	35,953
Income tax payables	10,199	1,483	11,612
Total current liabilities	851,685	123,873	432,385
Accrued expenses and other liabilities non current	518	75	460
Total non-current liabilities	518	75	460
Total liabilities	852,203	$ 123,948	432,845
VIEs
Variable Interest Entity [Line Items]
Cash and cash equivalents	401,424		210,280
Restricted cash	29,550
Short-term investments	168,993
Accounts receivable from third parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	111,718		4,348
Accounts receivable from a related party (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	260,984		249,548
Other receivables from related parties (net of allowance of nil and nil as of December 31, 2017 and 2018, respectively)	112,320		24,160
Inventories	231,975		50,692
Prepaid expenses and other current assets	46,499		22,986
Total current assets	1,363,463		562,014
Property, plant and equipment, net	11,301		3,086
Deferred tax assets	5,234		3,048
Intangible assets, net	169
Prepaid expenses and other non-current assets	3,636
Total non-current assets	20,340		6,134
Total assets	1,383,803		568,148
Accounts and notes payable current	548,481		291,643
Advances from customers	86,312		27,015
Amounts due to related parties	5,763		35,953
Accrued expenses and other liabilities	179,712		60,953
Income tax payables	10,199		11,612
Total current liabilities	830,467		427,176
Accrued expenses and other liabilities non current	518		460
Total non-current liabilities	518		460
Total liabilities	¥ 830,985		¥ 427,636

Organization and Principal Activities - Assets and Liabilities of VIEs and its Subsidiaries and Group's taken as Whole (Parenthetical) (Details) - VIEs - CNY (¥)	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Accounts Receivable, Net, Current
Accounts receivable from a related party, allowance
Other receivable from related parties, allowance

Organization and Principal Activities - Results of Operations and Cash Flows of VIEs and its Subsidiaries taken as Whole (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Variable Interest Entity [Line Items]
Revenue	¥ 2,561,229	$ 372,515	¥ 873,219	¥ 312,574
Net income	65,358	9,505	93,240	16,259
Net cash provided by operating activities	222,269	32,328	123,906	15,499
Net cash used in investing activities	(151,821)	(22,081)	(1,234)	(1,609)
Net cash provided by (used in) financing activities	604,975	$ 87,989	2,671	12,999
VIEs
Variable Interest Entity [Line Items]
Revenue	2,561,229		873,083	312,523
Net income	70,232		92,159	16,295
Net cash provided by operating activities	209,690		123,182	13,146
Net cash used in investing activities	(183,262)		¥ (1,234)	(1,609)
Net cash provided by (used in) financing activities	¥ (37,731)			¥ 12,999

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 CNY (¥) Installment Segment	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2018 USD ($)	Apr. 30, 2018	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Significant Accounting Policies [Line Items]
Foreign currency exchange buying rate	6.8755			6.8755
Rental expenses	¥ 3,900,000	¥ 1,100,000	¥ 400,000
Capital leases \| $				$ 0		$ 0	$ 0
Redemption period	5 years
Number of installment payments from customer \| Installment	2
Percentage of future gross profits from commercial sales group is entitled to as potential second installment payment.	50.00%
Percentage of estimated profit margin based on consideration of specific and relevant market factors	5.00%
Value added tax rate	16.00%			16.00%	17.00%
Accounts receivable from key customers	¥ 372,702,000	253,896,000	45,021,000
Deferred revenue	1,276,000	146,000	29,000
Advertising and market promotion expenses	130,796,000	39,638,000	8,065,000
Shipping expenses	140,456,000	20,044,000	2,633,000
Subsidy income	1,440,000	1,278,000	140,000
Uncertain tax positions, interest and penalties recognized	¥ 0	0	0
Number of operating segment \| Segment	1
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Operating lease,right of use asset	¥ 9,274,000
Operating lease, liability	9,168,000
P R C Contribution Plan
Significant Accounting Policies [Line Items]
Employee benefit expenses	18,889,000	8,016,000	3,199,000
Installation Services [Member]
Significant Accounting Policies [Line Items]
Deferred revenue	1,276,000
Revenue recognized amount	¥ 14,635,000	¥ 716,000	¥ 57,000
Xiaomi Inc
Significant Accounting Policies [Line Items]
Percentage of second installment payment arrangement to total revenue	9.00%	15.00%	15.30%

Significant Accounting Policies - Schedule of Property Plant and Equipment Estimated Useful Lives and Residual Rate (Detail)	12 Months Ended
	Dec. 31, 2018
Computers and Equipment \| Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful lives	2 years
Property, plant and equipment, Residual rate	0.00%
Computers and Equipment \| Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful lives	3 years
Property, plant and equipment, Residual rate	5.00%
Vehicles
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful lives	4 years
Property, plant and equipment, Residual rate	5.00%

Significant Accounting Policies - Schedule of Amortization of Finite-Lived Intangible Assets Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2018
Software
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Estimated useful lives	5 years

Significant Accounting Policies - Schedule of Disaggregation of Revenue by Type of Contract (Detail) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Disaggregation Of Revenue [Line Items]
Revenue	¥ 2,561,229	$ 372,515	¥ 873,219	¥ 312,574
Sales to Xiaomi
Disaggregation Of Revenue [Line Items]
Revenue	1,311,852		739,464	299,827
Sales to Xiaomi \| Xiaomi-branded Products
Disaggregation Of Revenue [Line Items]
Revenue	1,175,332		654,950	280,501
Sales to Xiaomi \| Viomi-branded Products
Disaggregation Of Revenue [Line Items]
Revenue	136,520		84,514	19,326
Sales to Third Party Customers
Disaggregation Of Revenue [Line Items]
Revenue	¥ 1,249,377		¥ 133,755	¥ 12,747

Concentration and Risks - Schedule of Accounts Receivable from Third Parties Concentration of Credit Risk (Details) - CNY (¥)
¥ in Thousands

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Concentration Risk [Line Items]

Accounts receivable

¥ 372,702

¥ 253,896

¥ 45,021

Company A | Accounts Receivable | Credit Risk

Concentration Risk [Line Items]

Accounts receivable

¥ 58,766

^[1]

Concentration risk, percentage

53.00%

^[1]

Company B | Accounts Receivable | Credit Risk

Concentration Risk [Line Items]

Accounts receivable

¥ 36,734

^[1]

Concentration risk, percentage

33.00%

^[1]

Company C | Accounts Receivable | Credit Risk

Concentration Risk [Line Items]

Accounts receivable

^[1]

¥ 2,778

Concentration risk, percentage

^[1]

64.00%

[1]	Less than 10%

Concentration and Risks - Schedule of Other Receivables from Related Parties Concentration of Credit Risk (Details) - Other Receivables - Credit Risk - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Xiaomi Inc
Concentration Risk [Line Items]
Other receivables	¥ 112,320	¥ 24,160
Concentration risk, percentage	100.00%	42.00%
Xiaomi H.K. Limited
Concentration Risk [Line Items]
Other receivables		¥ 33,448
Concentration risk, percentage		58.00%

Concentration and Risks - Summary of Revenue Concentration Risk (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Concentration Risk [Line Items]
Revenue	¥ 2,561,229	$ 372,515	¥ 873,219	¥ 312,574
Xiaomi Telecommunication Technology \| Sales Revenue, Net \| Revenue Concentration Risk
Concentration Risk [Line Items]
Revenue	¥ 1,311,852		¥ 739,464	¥ 299,827
Concentration risk, percentage	51.00%	51.00%	85.00%	96.00%

Concentration and Risks - Additional Information (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Concentration Risk [Line Items]
Revenue	¥ 2,561,229	$ 372,515	¥ 873,219	¥ 312,574
Contract With Xiaomi \| Viomi-branded Products
Concentration Risk [Line Items]
Revenue	¥ 136,520		¥ 84,514	¥ 19,326

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents Balance (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents	¥ 940,298	$ 136,761	¥ 279,952	$ 40,718	¥ 156,930	¥ 127,128
RMB
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents	332,702		206,951
US$
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents	¥ 607,596	$ 88,529	¥ 73,001	$ 11,163

Restricted Cash - Additional Information (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Cash And Cash Equivalents [Abstract]
Restricted cash	¥ 29,550	$ 4,298	¥ 0

Short-Term Investments - Schedule of Short-Term Investments Balance (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Schedule Of Investments [Line Items]
Short-term investments	¥ 168,993	$ 24,579	¥ 0
RMB
Schedule Of Investments [Line Items]
Short-term investments	100,022	100,022
US$
Schedule Of Investments [Line Items]
Short-term investments	¥ 68,971	$ 10,049

Inventories - Schedule of Inventories (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Inventory Disclosure [Abstract]
Finished goods	¥ 136,494		¥ 13,956
Raw materials	95,481		36,736
Inventories	¥ 231,975	$ 33,739	¥ 50,692

Inventories - Additional Information (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Inventory Disclosure [Abstract]
Inventory write-down	¥ 1,059	$ 154	¥ 81	¥ 1,658

Prepaid Expenses and Other Assets - Schedule of Prepaid Expenses and Other Assets (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Advances to suppliers	¥ 23,549		¥ 14,428
Other receivables	15,361		3,054
Prepayment for equipment	3,636
Other current assets	7,745		5,525
Rental deposits	235		276
Total	50,526		23,283
Less: non-current portion	(3,636)	$ (529)	0
Prepaid expenses and other current assets	¥ 46,890	$ 6,819	¥ 23,283

Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment, Net (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	¥ 16,778		¥ 6,323
Less: accumulated depreciation	(5,477)		(3,237)
Property, plant and equipment, net	11,301	$ 1,644	3,086
Computers and Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	16,270		5,815
Vehicles
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	¥ 508		¥ 508

Property, Plant and Equipment, Net - Additional Information (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Depreciation expense	¥ 2,244	¥ 1,680	¥ 1,222
Impairment charge	¥ 0	¥ 0	¥ 0

Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Payables And Accruals [Abstract]
Freight payable	¥ 50,680		¥ 9,799
Other tax payable	42,076		15,359
Accrued payroll and welfare	39,700		16,304
Product warranty	12,744		13,909
Marketing and promotion expenses	10,710		1,000
Professional fee payables	10,340
Installation fee payables	8,133
Deferred revenue	1,276		146
Deposits received related to unvested shares			496
Other current liabilities	25,789		4,871
Total	201,448		61,884
Less: non-current portion	(518)		(460)
Accrued expenses and other liabilities-current portion	¥ 200,930	$ 29,225	¥ 61,424

Accrued Expenses and Other Liabilities - Schedule of Product Warranty Activities (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Balance at December 31, 2016	¥ 13,909	¥ 2,483
Provided during the year	19,775	17,806
Utilized during the year	(20,940)	(6,380)
Balance at December 31, 2017	¥ 12,744	¥ 13,909

Revenue - Schedule of Revenue (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Disaggregation Of Revenue [Line Items]
Revenue	¥ 2,561,229	$ 372,515	¥ 873,219	¥ 312,574
Cost of revenues	1,843,432	268,116	598,036	232,544
Gross profit	717,797	$ 104,399	275,183	80,030
IoT-enabled Smart Home Products
Disaggregation Of Revenue [Line Items]
Revenue	2,081,273		712,317	273,282
Cost of revenues	1,514,344		499,739	206,679
Gross profit	566,929		212,578	66,603
Smart Water Purification Systems
Disaggregation Of Revenue [Line Items]
Revenue	930,178		570,784	250,442
Cost of revenues	614,829		399,788	191,848
Gross profit	315,349		170,996	58,594
Smart Kitchen Products
Disaggregation Of Revenue [Line Items]
Revenue	744,990		50,656
Cost of revenues	596,005		34,987
Gross profit	148,985		15,669
Other Smart Products
Disaggregation Of Revenue [Line Items]
Revenue	406,105		90,877	22,840
Cost of revenues	303,510		64,964	14,831
Gross profit	102,595		25,913	8,009
Consumable Products
Disaggregation Of Revenue [Line Items]
Revenue	141,940		87,500	19,376
Cost of revenues	67,433		48,123	10,644
Gross profit	74,507		39,377	8,732
Other Products
Disaggregation Of Revenue [Line Items]
Revenue	323,381		72,686	19,859
Cost of revenues	247,717		49,489	15,166
Gross profit	75,664		23,197	4,693
Total of Sales of Product
Disaggregation Of Revenue [Line Items]
Revenue	2,546,594		872,503	312,517
Cost of revenues	1,829,494		597,351	232,489
Gross profit	717,100		275,152	80,028
Installation Services
Disaggregation Of Revenue [Line Items]
Revenue	14,635		716	57
Cost of revenues	13,938		685	55
Gross profit	¥ 697		¥ 31	¥ 2

Income Tax (Benefits) Expenses - Additional Information (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Income tax rate	25.00%	25.00%	25.00%
High and New Technology Enterprises
Income Tax Disclosure [Line Items]
Income tax rate	15.00%	15.00%	15.00%
Hong Kong
Income Tax Disclosure [Line Items]
Income tax rate	16.50%
PRC
Income Tax Disclosure [Line Items]
Percentage of qualified research and development expenses enterprises are entitled to claim as additional tax deduction	75.00%	50.00%	50.00%
Withholding tax rate	10.00%
Undistributed earnings available for distribution	¥ 282,130	¥ 95,658
Statute of limitations year	3 years
Statute of limitations extended period	5 years
PRC \| Arrangement Between PRC and Hong Kong Special Administrative Region on Avoidance of Double Taxation and Prevention of Fiscal Evasion with Respect to Taxes on Income and Capital
Income Tax Disclosure [Line Items]
Withholding tax rate	5.00%
Minimum percentage of equity interests in PRC foreign-invested enterprise to be subject to special withholding tax rate	25.00%
Withholding income tax rate on dividends for Hong Kong holding company which is not considered to be beneficial owner	10.00%
PRC \| 2018
Income Tax Disclosure [Line Items]
Percentage of qualified research and development expenses enterprises are entitled to claim as additional tax deduction	75.00%
PRC \| 2020
Income Tax Disclosure [Line Items]
Percentage of qualified research and development expenses enterprises are entitled to claim as additional tax deduction	75.00%
PRC \| Enterprise Income Tax
Income Tax Disclosure [Line Items]
Income tax rate	25.00%
PRC \| Subsidiaries and VIEs and Predecessor Operations
Income Tax Disclosure [Line Items]
Income tax rate	25.00%	25.00%	25.00%
PRC \| High and New Technology Enterprises
Income Tax Disclosure [Line Items]
Income tax rate	15.00%

Income Tax (Benefits) Expenses - Current and Deferred Components of Income Taxes (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Income Tax Disclosure [Abstract]
Current tax expenses	¥ 26,247		¥ 15,519
Deferred tax benefit	(2,186)	$ (318)	(801)	¥ (2,247)
Income tax (benefits) expenses	¥ 24,061	$ 3,500	¥ 14,718	¥ (2,247)

Income Tax (Benefits) Expenses - Reconciliation between Income Tax Expenses Computed by Applying PRC Enterprise Tax Rate Before Income Taxes and Actual Provision (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Income Tax Disclosure [Abstract]
Income from operations in the PRC	¥ 93,910		¥ 106,868	¥ 13,546
Income (loss) from overseas entities	(4,499)		1,090	466
Income before income tax benefits (expenses)	89,411	$ 13,004	107,958	14,012
Tax expense at PRC enterprise income tax rate of 25%	22,353		26,990	3,503
Income tax on tax holiday	(9,632)		(10,989)	(1,414)
Tax effect of permanence differences	(7,871)		(2,640)	(1,187)
Effect of income tax rate change				3,179
Change in valuation allowance	602		760	(7,756)
Effect of share-based compensation	17,492		873	1,587
Effect of income tax in jurisdictions other than the PRC	1,117		(276)	(159)
Income tax (benefits) expenses	¥ 24,061	$ 3,500	¥ 14,718	¥ (2,247)

Income Tax (Benefits) Expenses - Reconciliation between Income Tax Expenses Computed by Applying PRC Enterprise Tax Rate Before Income Taxes and Actual Provision (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Income tax rate	25.00%	25.00%	25.00%
High and New Technology Enterprises
Income Tax Disclosure [Line Items]
Income tax rate	15.00%	15.00%	15.00%

Income Tax (Benefits) Expenses - Per Share Effect of Tax Holidays (Details) - ¥ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net income per share effect – basic	¥ 0.22	¥ 0.53	¥ 0.12
Net income per share effect – diluted	¥ 0.20	¥ 0.41	¥ 0.12

Income Tax (Benefits) Expenses - Significant Components of Deferred Tax Assets (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Inventory write downs	¥ 421	¥ 541
Accrued expenses and others	4,616	2,485
Deferred income	191	22
Net operating loss carry forwards	1,560	952
Total deferred tax assets	6,788	4,000
Less: valuation allowance	(1,554)	(952)
Deferred tax assets, net	¥ 5,234	¥ 3,048

Income Tax (Benefits) Expenses - Movement of Valuation Allowance (Details) - Valuation Allowance of Deferred Tax Assets - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Balance at beginning of the year	¥ 952	¥ 192	¥ 7,948
Provided	602	760	190
Reversals	0		(7,946)
Balance at end of the year	¥ 1,554	¥ 952	¥ 192

Ordinary Shares - Additional Information (Details) - $ / shares		12 Months Ended
	Aug. 23, 2018	Dec. 31, 2018	Sep. 25, 2018	Aug. 22, 2018	Jun. 30, 2018	Dec. 31, 2017
Class Of Stock [Line Items]
Common stock, par value per share	$ 0.00001			$ 0.0001
Preferred shares, par value	$ 0.00001			$ 0.0001
Number of ordinary shares	10
Surrendered percentage of ordinary shares after share split	90.00%
Stock, conversion basis		IPO, 16,145,454 issued class A ordinary shares held by certain key management founders, 33,818,182 issued Class B Ordinary Shares held by Red Better, and 67,636,364 issued Class B Ordinary Shares held by Mr. Chen’s wholly-owned entity Viomi Limited was automatically converted by way of re-designation and re-classification into Post-IPO Class B Ordinary Shares on a one-for-one basis, and the rest of the outstanding class A ordinary shares, the rest of the outstanding class B Ordinary Shares, and all outstanding Series A Preferred Shares was automatically converted by way of re-designation and re-classification into Post-IPO Class A Ordinary Shares on a one-for-one basis.
Post-IPO
Class Of Stock [Line Items]
Common stock, shares authorized	5,000,000,000
Ordinary shares, voting rights		Each Post-IPO Class A Ordinary Share is entitled to one vote, and each Post-IPO Class B Ordinary Share is entitled to ten (10) votes, voting together as one class.
Stock, conversion basis		Each Post-IPO Class B Ordinary Share is convertible into one Post-IPO Class A Ordinary Share at any time by the holder thereof.
Class A Ordinary Shares
Class Of Stock [Line Items]
Common stock, shares authorized				346,545,454
Common stock, par value per share		$ 0.00001		$ 0.0001
Ordinary shares, outstanding		0				25,363,636
Ordinary shares, voting rights		Each ordinary share is entitled to one vote
Common stock, shares issued	4,000,000				33,818,182	33,818,182
Ordinary shares, transferred					16,145,454
Ordinary shares, surrendered					17,672,728
Fair value per share	$ 3.30
Class A Ordinary Shares \| Post-IPO
Class Of Stock [Line Items]
Common stock, shares authorized	4,800,000,000	4,800,000,000	4,800,000,000
Common stock, par value per share	$ 0.00001	$ 0.00001	$ 0.00001
Ordinary shares, outstanding		90,200,000
Common stock, shares issued		90,200,000
Class A Ordinary Shares \| Post-IPO \| Key Management Founders
Class Of Stock [Line Items]
Common stock, shares issued		16,145,454
Class B Ordinary Shares \| Post-IPO
Class Of Stock [Line Items]
Common stock, shares authorized	150,000,000	150,000,000	150,000,000
Common stock, par value per share	$ 0.00001	$ 0.00001	$ 0.00001
Ordinary shares, outstanding		117,600,000
Common stock, shares issued		117,600,000
Class B Ordinary Shares \| Post-IPO \| Red Better Limited
Class Of Stock [Line Items]
Common stock, shares issued		33,818,182
Class B Ordinary Shares \| Post-IPO \| Viomi Limited
Class Of Stock [Line Items]
Common stock, shares issued		67,636,364
Designated Common Stock \| Post-IPO
Class Of Stock [Line Items]
Common stock, shares authorized			50,000,000
Common stock, par value per share			$ 0.00001

Redeemable Convertible Preferred and Class B Ordinary Shares - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	7 Months Ended	12 Months Ended
	Jul. 31, 2015	Dec. 31, 2015	Dec. 31, 2018	Dec. 31, 2017
Series A Preferred Shares
Temporary Equity [Line Items]
Stock issued			0	18,181,818
Temporary equity per share			$ 0.00001	$ 0.00001
Dividend rights rate percentage		8.00%
Liquidation rights rate percentage		150.00%
Series A Preferred Shares \| Investors
Temporary Equity [Line Items]
Stock issued	18,181,818
Temporary equity per share	$ 0.0001
Shares issued price per share	$ 1.1
Stock issued for consideration including conversion of outstanding bridge loans	$ 20,000
Outstanding bridge loans	$ 5,250
Series A Preferred Shares and Class B Ordinary Shares
Temporary Equity [Line Items]
Initial conversion ratio description	1-to-1 initial conversion ratio
Compound interest return per annum on issuance price	6.00%
Class B Ordinary Shares
Temporary Equity [Line Items]
Dividend rights rate percentage		8.00%
Liquidation rights rate percentage		150.00%
Stock issued during upon exchange of equity interest		67,636,364

Redeemable Convertible Preferred and Class B Ordinary Shares - Summary of Change Balance of Series A Preferred Shares and Class B Ordinary Shares (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Temporary Equity [Line Items]
Beginning Balance	¥ 407,928,000	¥ 423,999,000	¥ 388,860,000
Accretion of preferred shares	6,563,000	8,834,000	8,221,000
Foreign exchange	19,667,000	(24,905,000)	26,918,000
Conversion of Series A Preferred Shares and ClassB Ordinary Shares to ordinary shares upon thecompletion of the IPO on September 25, 2018	(434,158,000)
Ending Balance		407,928,000	423,999,000
Series A Preferred Shares
Temporary Equity [Line Items]
Beginning Balance	151,045,000	151,279,000	133,573,000
Accretion of preferred shares	6,563,000	8,834,000	8,221,000
Foreign exchange	7,487,000	(9,068,000)	9,485,000
Conversion of Series A Preferred Shares and ClassB Ordinary Shares to ordinary shares upon thecompletion of the IPO on September 25, 2018	(165,095,000)
Ending Balance		151,045,000	151,279,000
Class B Ordinary Shares
Temporary Equity [Line Items]
Accretion of preferred shares	0	0	0
Founder \| Class B Ordinary Shares
Temporary Equity [Line Items]
Beginning Balance	51,376,000	54,545,000	51,057,000
Foreign exchange	2,437,000	(3,169,000)	3,488,000
Conversion of Series A Preferred Shares and ClassB Ordinary Shares to ordinary shares upon thecompletion of the IPO on September 25, 2018	(53,813,000)
Ending Balance		51,376,000	54,545,000
Xiaomi Telecommunication Technology \| Class B Ordinary Shares
Temporary Equity [Line Items]
Beginning Balance	205,507,000	218,175,000	204,230,000
Foreign exchange	9,743,000	(12,668,000)	13,945,000
Conversion of Series A Preferred Shares and ClassB Ordinary Shares to ordinary shares upon thecompletion of the IPO on September 25, 2018	¥ (215,250,000)
Ending Balance		¥ 205,507,000	¥ 218,175,000

Redeemable Convertible Preferred and Class B Ordinary Shares - Summary of Change Balance of Series A Preferred Shares and Class B Ordinary Shares (Parenthetical) (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Temporary Equity [Line Items]
Accretion of preferred shares	¥ 6,563,000	¥ 8,834,000	¥ 8,221,000
Class B Ordinary Shares
Temporary Equity [Line Items]
Accretion of preferred shares	¥ 0	¥ 0	¥ 0
Stock issued during upon exchange of equity interest				67,636,364
Class B Ordinary Shares \| Restricted Share Arrangement
Temporary Equity [Line Items]
Stock issued during upon exchange of equity interest				50,727,273

Share-Based Compensation - Schedule of Compensation Expense Recognized for Share-Based Awards (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	¥ 116,611	¥ 5,821	¥ 10,578
Restricted Shares Owned by the Founder – Equity Component
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	826	2,670	6,051
Restricted Shares Owned by the Founder – Liability Component
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	212	286	266
Restricted Shares Owned by the Founder on Behalf of Certain Key Management Founders
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	14	48	93
Share Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	25,391	¥ 2,817	¥ 4,168
Shares Awarded to Mr. Chen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expenses	¥ 90,168

Share-Based Compensation - Additional Information (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands			1 Months Ended		12 Months Ended
	Aug. 23, 2018 $ / shares shares	Sep. 17, 2015 shares	Jun. 30, 2014	May 31, 2014 CNY (¥)	Dec. 31, 2018 CNY (¥) ¥ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2016 ¥ / shares shares	Jun. 30, 2018 shares	Dec. 31, 2015 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Capital contribution					¥ 2,705	$ 393	¥ 2,671
Weighted average grant date fair value of options granted \| (per share)					¥ 18.23	$ 2.66	¥ 6.01	$ 0.90	$ 0.38	¥ 2.50
Options exercised					0	0	0		0	0
Unrecognized compensation expenses related to options \| ¥					¥ 53,879
Class A Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, issued	4,000,000						33,818,182	33,818,182			33,818,182
2015 Share Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share incentive plan effective period		10 years
Maximum number of shares issued under share incentive plan		12,727,272
Number of share options granted to employees under stock incentive plans					5,460,000	5,460,000	2,700,000		1,860,000	1,860,000
2015 Share Incentive Plan \| Vested after 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage							50.00%		50.00%	50.00%
2015 Share Incentive Plan \| Vested in Two Equal Installments over Following 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage							50.00%		50.00%	50.00%
2018 Share Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares issued under share incentive plan											17,672,728
Number of share options granted to employees under stock incentive plans					670,000	670,000
2015 Share Incentive Plan and 2018 Share Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share options granted to employees under stock incentive plans					6,130,000	6,130,000	2,700,000		1,860,000	1,860,000
2015 Share Incentive Plan and 2018 Share Incentive Plan \| Vested after 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share options granted to employees under stock incentive plans					5,500,000	5,500,000
2015 Share Incentive Plan and 2018 Share Incentive Plan \| Vested in Two Equal Installments over Following 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share options granted to employees under stock incentive plans					630,000	630,000
2015 Share Incentive Plan and 2018 Share Incentive Plan \| With Respect to 5,500,000 Share Options Granted, Vesting after 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage					40.00%	40.00%
2015 Share Incentive Plan and 2018 Share Incentive Plan \| With Respect to 5,500,000 Share Options Granted, Vested in Three Equal Installments over Following 36 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage					60.00%	60.00%
2015 Share Incentive Plan and 2018 Share Incentive Plan \| With Respect to 630,000 Share Options Granted, Vesting after 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage					50.00%	50.00%
2015 Share Incentive Plan and 2018 Share Incentive Plan \| With Respect to 630,000 Share Options Granted, Vested in Two Equal Installments over Following 24 Months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share options vested percentage					50.00%	50.00%
Founder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Capital contribution \| ¥				¥ 7,500
Equity interests				60.00%
Equity investments amount \| ¥				¥ 7,500
Repurchase of shares lapse rate			0.25
Vesting period			4 years
Founder \| Class A Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, issued	4,000,000
Estimated fair value per share \| $ / shares	$ 3.30
Founder \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unsettled restricted shares granted												50,727,273
Tianjin Jinxing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Capital contribution \| ¥				¥ 5,000
Equity interests				40.00%
Equity investments amount \| ¥				¥ 5,000
Key Management Founders
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Equity investments amount \| ¥				¥ 2,500

Share-Based Compensation - Summary of Restricted Shares Activity (Details) - shares

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Restricted Shares Owned by the Founder on Behalf of Certain Key Management Founders

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares, Outstanding, Beginning Period

8,454,546

16,909,092

25,363,638

Number of shares, Surrender and cancellation

^[1]

(5,918,182)

Number of shares, Vested

(2,536,364)

(8,454,546)

Number of shares, Outstanding, Ending Period

8,454,546

16,909,092

Restricted Shares Owned By Founder On His Own Behalf

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares, Outstanding, Beginning Period

16,909,091

33,818,182

50,727,273

Number of shares, Vested

(16,909,091)

Number of shares, Outstanding, Ending Period

16,909,091

33,818,182

Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares, Outstanding, Beginning Period

25,363,637

50,727,274

76,090,911

Number of shares, Surrender and cancellation

^[1]

(5,918,182)

Number of shares, Vested

(19,445,455)

(25,363,637)

Number of shares, Outstanding, Ending Period

25,363,637

50,727,274

[1]

Share-Based Compensation - Summary of Restricted Shares Activity (Parenthetical) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Aug. 23, 2018	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested restricted shares				25,363,637	50,727,274	76,090,911
Class A Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, issued		4,000,000	33,818,182	33,818,182
Ordinary shares, surrendered			17,672,728
Class A Ordinary Shares \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, surrendered			17,672,728
Unvested restricted shares			5,918,182
Acceleration of vesting shares	5,918,182
Mr. Chen \| Class A Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, issued		4,000,000
Mr. Chen \| Class A Ordinary Shares \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, held			33,818,182
Key Management Founders \| Class A Ordinary Shares \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares, issued			16,145,454

Share-Based Compensation - Schedule of Movement of Liability Awards with Respect to Unsettled Restricted Shares Granted (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expenses	¥ 116,611	¥ 5,821	¥ 10,578
Restricted Shares Owned By Founder On His Own Behalf
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Balance outstanding	4,738	4,550	4,181
Share-based compensation expenses	212	286	266
Foreign currency translation adjustment	408	(98)	103
Balance outstanding	0	¥ 4,738	¥ 4,550
Restricted Shares Owned By Founder On His Own Behalf \| IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Conversion of Restricted Shares to ordinary shares upon the completion of the IPO on September 25, 2018	¥ (5,358)

Share-Based Compensation - Assumptions used to Determine Fair Value of Share Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate			2.86%
Risk-free interest rate, minimum	3.62%	3.06%
Risk-free interest rate, maximum	3.92%	3.89%
Expected volatility, minimum	45.51%	47.02%	50.14%
Expected volatility, maximum	46.99%	49.44%	50.15%
Expected life of option (years)	10 years	10 years	10 years
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value per ordinary share	$ 1.61	$ 0.76
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value per ordinary share	$ 3.30	$ 1.59	$ 0.51

Share-Based Compensation - Summary of Stock Option Activity (Details) - 2015 Share Incentive Plan and 2018 Share Incentive Plan - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted Share Number, Outstanding, Beginning Period	7,540,000	5,620,000	4,740,000
Options granted Share Number, Granted	6,130,000	2,700,000	1,860,000
Options granted Share Number, Forfeited	(410,000)	(780,000)	(980,000)
Options granted Share Number, Outstanding, Ending Period	13,260,000	7,540,000	5,620,000
Weighted average exercise price, Outstanding, Beginning Period	$ 0.25	$ 0.12	$ 0.06
Weighted average exercise price, Granted	0.64	0.52	0.24
Weighted average exercise price, Forfeited	0.43	0.27	0.04
Weighted average exercise price, Outstanding, Ending Period	$ 0.43	$ 0.25	$ 0.12

Share-Based Compensation - Summary Regarding Share Options Granted (Details) - 2015 and 2018 Share Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Number, Outstanding	13,260,000	7,540,000	5,620,000	4,740,000
Options Number, Exercisable	3,945,000	2,612,500	915,000
Options Number, Expected to vest	8,290,350	4,385,475	4,187,450
Weighted-average exercise price per option, Outstanding	$ 0.43	$ 0.25	$ 0.12	$ 0.06
Weighted-average exercise price per option, Exercisable	0.08	0.06	0.02
Weighted-average exercise price per option, Expected to vest	$ 0.57	$ 0.35	$ 0.14
Weighted-average remaining exercise contractual life (years), Outstanding	8 years 4 months 24 days	8 years 7 months 24 days	9 years 2 months 19 days
Weighted-average remaining exercise contractual life (years), Exercisable	7 years 10 days	7 years 11 months 26 days	8 years 9 months 29 days
Weighted-average remaining exercise contractual life (years), Expected to vest	8 years 11 months 19 days	9 years	9 years 3 months 14 days
Aggregate intrinsic value, Outstanding	$ 18,705	$ 3,697	$ 1,854
Aggregate intrinsic value, Exercisable	1,752	987	366
Aggregate intrinsic value, Expected to vest	$ 15,373	$ 2,695	$ 1,324

Net (Loss) Income Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥) ¥ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares	Dec. 31, 2016 CNY (¥) ¥ / shares shares
Numerator:
Numerator for basic calculation - Net (loss) income attributable to ordinary shareholders of the Company	¥ 50,544	$ 7,350	¥ 8,033	¥ (3,453)
Denominator:
Denominator for basic calculation - weighted average ordinary shares outstanding	71,771,033	71,771,033	20,684,681	12,230,136
Dilutive effect of share options	7,819,747	7,819,747	4,895,125
Denominator for diluted calculation	79,590,780	79,590,780	25,579,806	12,230,136
Basic net (loss) income per ordinary share \| (per share)	¥ 0.70	$ 0.10	¥ 0.39	¥ (0.28)
Diluted net (loss) income per ordinary share \| (per share)	¥ 0.64	$ 0.09	¥ 0.31	¥ (0.28)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

Net (Loss) Income Per Share - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Class B Ordinary Shares \| Red Better and Shunwei
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive outstanding shares	67,636,364	67,636,364
Series A Preferred Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive outstanding shares	18,181,818	18,181,818
Share Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive outstanding shares		3,370,739
Restricted Shares \| Founder
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive outstanding shares	67,636,364	67,636,364
Unvested Restricted Shares \| Founder
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive outstanding shares	13,079,391	21,520,813

Related Party Transactions - Schedule of Related Party Transaction Relationship (Details)	12 Months Ended
	Dec. 31, 2018
Founder
Related Party Transaction [Line Items]
Relationship with the Group	Founder
Xiaomi Inc.
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi
Xiaomi H.K. Limited
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi
Xiaomi Telecommunication Technology
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi
Tianjin Jinxing
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi
Xiaomi Software
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi
Guangzhou Xiaomi
Related Party Transaction [Line Items]
Relationship with the Group	Controlled by Xiaomi

Related Party Transactions - Additional Information (Details) - Xiaomi	12 Months Ended
	Dec. 31, 2018
Business Corporation Agreement
Related Party Transaction [Line Items]
Related party transaction expiration	2019-08
Related party transactions agreement extend period	1 year
Business Corporation Agreement \| Minimum
Related Party Transaction [Line Items]
Related party transaction agreement objection period	30 days
Youpin Commission Sales Agreement
Related Party Transaction [Line Items]
Related party transaction, expire date	Dec. 31, 2018
Related party transaction agreement termination notice period	30 days
Related party transaction renewed date	Dec. 31, 2019
Related party transaction commission percentage in sales excluding customer refunds	8.00%

Related Party Transactions - Schedule of Related Party Transactions (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Other receivables from related parties	¥ 112,320		¥ 57,608		$ 16,336
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)	5,763		35,953		$ 838
Purchase from related parties	14,733	$ 2,143	1,296	¥ 1,321
A related party	1,311,852	$ 190,801	739,464	299,827
Selling and marketing expenses	24,598		3,327	166
Interest expense from related party	333		1,271	1,489
Xiaomi Inc.
Related Party Transaction [Line Items]
Selling and marketing expenses	20,824		3,327	166
Guangzhou Xiaomi
Related Party Transaction [Line Items]
Selling and marketing expenses	3,774
Xiaomi Software
Related Party Transaction [Line Items]
Interest expense from related party	440		1,761	1,761
Xiaomi H.K. Limited
Related Party Transaction [Line Items]
Interest income	107		490	272
Xiaomi Telecommunication Technology
Related Party Transaction [Line Items]
Accounts receivable from a relate party	260,984		249,548
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)	3,876		1,225
Purchase from related parties	18,235		1,685	1,327
A related party	1,311,852		739,464	¥ 299,827
Xiaomi H.K. Limited
Related Party Transaction [Line Items]
Other receivables from related parties			33,448
Xiaomi Inc.
Related Party Transaction [Line Items]
Other receivables from related parties	112,320		24,160
Xiaomi Software
Related Party Transaction [Line Items]
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)			32,228
Guangzhou Xiaomi
Related Party Transaction [Line Items]
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)	¥ 1,887
Tianjin Jinxing
Related Party Transaction [Line Items]
Amounts due to related parties (including amounts due to related parties of the consolidated VIEs without recourse to the Group of RMB35,953 and RMB5,763 as of December 31, 2017 and 2018, respectively)			¥ 2,500

Related Party Transactions - Schedule of Related Party Transactions (Parenthetical) (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Amounts due to related parties	¥ 5,763	¥ 35,953		$ 838
Xiaomi H.K. Limited \| Loan to Related Party
Related Party Transaction [Line Items]
Loan to related party \| $				$ 5,000
Description of interest rate	3 month Libor add 10bps
Basis spread on variable rate	0.10%			0.10%
Loan term	3 months
Extended loan term	3 months
Xiaomi Software \| Loan from Related Party
Related Party Transaction [Line Items]
Loan from related party	¥ 31,900
Interest rate of loan	5.52%
Loan term	3 months
Extended loan term	3 months
Tianjin Jinxing
Related Party Transaction [Line Items]
Amounts due to related parties		2,500
Tianjin Jinxing \| Red Better Limited
Related Party Transaction [Line Items]
Proceeds from shareholder with understanding that amount will be repaid to related party		¥ 2,671	$ 409

Fair Value Measurements - Summary of Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - Short-term Investment
¥ in Thousands

Dec. 31, 2018

CNY (¥)

^[1]

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Assets measured at fair value

¥ 168,993

Level 2

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Assets measured at fair value

¥ 168,993

[1]	Short-term investments represent structured deposits and the Company values these short-term investments based on quoted prices of similar products provided by banks at the end of each period, and accordingly, the Company classifies the valuation techniques that use these inputs as Level 2

Commitments and Contingencies - Schedule of Future Minimum Commitments under Non-Cancellable Agreements (Details) ¥ in Thousands	Dec. 31, 2018 CNY (¥)
Commitments And Contingencies Disclosure [Abstract]
2019	¥ 4,284
2020	2,947
2021	1,600
2022 and after	978
Total	¥ 9,809

Commitments and Contingencies - Additional Information (Details) - CNY (¥) ¥ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Committed investment amount		¥ 6,000
Subsequent Event
Subsequent Event [Line Items]
Committed investment amount paid	¥ 6,000

Subsequent Events - Additional Information (Details) - Subsequent Event	Mar. 18, 2019 $ / shares shares
Subsequent Event [Line Items]
Dividend approved date	Mar. 18, 2019
Cash dividend per share	$ 0.0333
Dividend record date	Mar. 28, 2019
American Depositary Shares
Subsequent Event [Line Items]
Cash dividend per share	$ 0.10
Number of ordinary shares \| shares	3

Restricted Net Assets - Additional Information (Detail) - CNY (¥)	Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	¥ 18,750	¥ 13,750