Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Summary of Stock Option Activity under Equity Plans

A summary of stock option activities is as follows:

	Shares	Weighted Average Exercise Price	Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
			(Years)	(In thousands)
Option:
Options outstanding as of December 31, 2020	597,354	$5.86
Granted	—
Options outstanding as of September 30, 2021	597,354	$5.86	6.55	$	83
Options exercisable as of September 30, 2021	597,354	$5.86	6.55	$	83
Options vested and expected to vest as of September 30, 2021	597,354	$5.86	6.55	$	83

Summary of RSU and RSA Activity under Equity Plans

A summary of RSA and RSU activities is as follows:

	Shares	Weighted Average Grant Date Fair Value per Share
RSA:
RSAs outstanding as of December 31, 2020	4,183,624	$1.37
Released	(4,183,624)
RSAs outstanding as of September 30, 2021	—
RSU:
RSUs outstanding as of December 31, 2020	11,983,636	$12.43
Granted	3,287,904	$11.00
Released	(8,851,891)	$12.46
Forfeited	(1,519,749)	$11.68
RSUs outstanding as of September 30, 2021	4,899,900	$11.64
PRSU:
PRSUs outstanding as of December 31, 2020	1,101,683	$6.72
Granted	9,141	$1.97
Forfeited	(780,320)	$6.66
PRSUs outstanding as of September 30, 2021	330,504	$6.72

Summary of ESPP Valuation Assumptions

The weighted-average grant date fair value of purchase rights granted under the ESPP and the weighted-average assumptions used in the model were as follows:

	Nine Months Ended September 30, 2021
Weighted average grant date fair value of purchase rights issued under ESPP	$4.59
Expected term, in years	0.75
Expected volatility	97.90%
Risk-free interest rate	4%
Expected dividend yield	0.00%

Stock-Based Compensation Expense

The following table presents stock-based compensation expense included in the Company’s consolidated statements of operations (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Cost of revenue	$	541	$	2	$	1,508	$	2
Research and development	2,794		11		10,458		32
Sales and marketing	1,177		3		44,779		3
General and administrative	12,135		69		24,637		204
Total stock-based compensation expense	$	16,647	$	85	$	81,382	$	241