Summary of assumptions used for grant date fair value under binomial tree option pricing model

The grant date fair value of each share-based award is estimated on the date of grant using the binomial tree option pricing model with the following assumptions used for years presented:


	Year ended December 31, 2020			Year ended December 31, 2021			Year ended December 31, 2022
Fair value of ordinary share (US$)		0.09		4.34~4.87				—
Risk-free interest rates		0.66	%		0.07	%		—
Expected volatility range		59.2	%		52.02	%		—
Expected dividend yield		0.82	%		—			—
Fair value per option granted (US$)		0.02		2.44~2.56				—

Schedule of share-based compensation expense by function

Total share-based compensation expenses recorded by the Group are as follows:


	For the year ended December 31,
	2020			2021			2022
	RMB			RMB			RMB		US$
Cost of revenues		1,044			1,027			686		99
Research and development		29,091			5,996			1,580		229
Selling and marketing		(1,087	)		1,339			1,899		275
General and administrative		51,934			(1,212	)		3,698		536
Total		80,982			7,150			7,863		1,139

Restricted shares activity

The following table summarizes the Company’s option activity under the 2014 Restricted Shares Plan during the years ended December 31, 2020, 2021 and 2022, respectively:


	Number of shares			Weighted Average Exercise Price (US$)		Weighted Average Grant Date Fair Value (US$)		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (US$)
Outstanding at January 1, 2020		6,527,504			0.34		1.50		4.31		150
Exercised		(1,001,674	)		0.34		1.91
Modified in June 2020		(5,525,830	)		0.34		1.42
Outstanding at December 31, 2020		—
Exercised		—
Outstanding at December 31, 2021 and 2022		—
Vested and expected to vest at December 31, 2021 and 2022		—
Exercisable as at December 31, 2021 and 2022		—

The following table summarizes the restricted shares activity pursuant to the 2014 Restricted Shares Plan for the years ended December 31, 2020, 2021 and 2022, respectively:


	Number of shares			Weighted average grant date fair value (US$) after modification
Unvested at January 1, 2020		16,448,965			0.92
Modified in June 2020		5,525,830			1.62
Vested		(12,272,973	)		1.32
Forfeited		(6,061,820	)		0.77
Unvested at December 31, 2020		3,640,002			0.88
Granted		5,994,400			0.14
Vested		(2,016,463	)		0.78
Forfeited		(1,055,299	)		1.00
Unvested at December 31, 2021		6,562,640			0.22
Granted		—			—
Vested		(2,160,940	)		0.36
Forfeited		(373,150	)		0.26
Unvested at December 31, 2022		4,028,550			0.14

Restricted shares activity

The following table summarizes the Group’s options activity under the 2013 Incentive Scheme during the years ended December 31, 2020, 2021 and 2022, respectively:


	Number of shares			Weighted Average Exercise Price (US$)		Weighted Average Grant Date Fair Value (US$)		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (US$)
Outstanding at January 1, 2020		33,273,025			0.34		1.13		4.01		765
Exercised		(4,852,510	)		0.34		1.10
Modified in June 2020		(28,420,515	)		0.34		1.13
Outstanding at December 31, 2020		—			—		—		—		—
Exercised		—			—		—		—		—
Outstanding at December 31, 2021 and 2022
Vested and expected to vest at December 31, 2021and 2022		—
Exercisable as at December 31, 2021 and 2022		—

The following table summarizes the restricted shares activity pursuant to the 2013 Incentive Scheme for the years ended December 31, 2020, 2021 and 2022, respectively:


	Number of shares			Weighted average grant date fair value (US$) after modification
Outstanding at January 1, 2020		4,909,057			1.06
Modified in June 2020		28,420,515			1.33
Granted		1,600,000			0.21
Vested		(30,310,465	)		1.33
Forfeited		(364,377	)		0.90
Unvested at December 31, 2020		4,254,730			0.64
Granted		5,773,520			0.17
Vested		(1,416,898	)		0.79
Forfeited		(1,014,882	)		0.81
Unvested at December 31, 2021		7,596,470			0.23
Granted		469,490			0.08
Vested		(2,350,790	)		0.27
Forfeited		(628,180	)		0.50
Unvested at December 31, 2022		5,086,990			0.17

Restricted shares activity

The following table summarizes the restricted shares activity pursuant to the 2011 Share Award Scheme for the years ended December 31, 2020, 2021 and 2022, respectively:


	Number of shares			Weighted average grant date fair value (US$)
Unvested at January 1, 2020		4,066,803			0.69
Granted		596,920			0.21
Vested		(1,170,395	)		0.68
Forfeited		(1,549,603	)		0.57
Unvested at December 31, 2020		1,943,725			0.64
Granted		1,596,100			0.26
Vested		(1,687,405	)		0.36
Forfeited		(1,643,470	)		0.59
Unvested at December 31, 2021		208,950			0.39
Granted		—			—
Vested		(121,775	)		0.49
Forfeited		—			—
Unvested at December 31, 2022		87,175			0.26