Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense recognized in the Company’s consolidated statements of operations and comprehensive loss is classified as follows (in thousands):

	Year Ended December 31,
	2022		2021		2020
Cost of revenue	$	668	$	1,018	$	965
Research and development	2,858		2,538		2,288
Selling and marketing	2,936		1,615		1,091
General and administrative	15,146		18,700		18,461
Total stock-based compensation expense	$	21,608	$	23,871	$	22,805

Summary of RSU Activity

The table below summarizes the Company's activity and related information for its ISUs:

	RSUs and DSUs			PSUs
	Number of Shares	Weighted Average Grant Date Fair Value		Number of Shares		Weighted Average Grant Date Fair Value
Unvested at December 31, 2021	5,536,925	$	4.04	707,088		$	4.66
Granted	2,534,144	$	3.86	1,249,383		$	4.14
Incremental awards	—	$	—	1,638,775	(1)	$	4.66
Vested	(2,767,524)	$	3.62	—		$	—
Cancelled or forfeited	(280,516)	$	4.19	(44,391)		$	4.34
Unvested at December 31, 2022	5,023,029	$	4.16	3,550,855		$	4.33
Vested and unreleased	248,978			—
Outstanding at December 31, 2022	5,272,007			3,550,855

(1) Includes incremental PSUs which have been accrued as of December 31, 2022 based on the expected level of achievement of previously granted awards.

Summary of Company's Stock Option Activity and Related Information

A summary of the Company’s stock option activity and related information is as follows:

	Number of Stock Options Outstanding	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
					(In thousands)
Options outstanding at December 31, 2021	7,195,398	$	6.97	6.1	$	5,203
Options granted	—	—
Options exercised	(28,812)	2.76
Options cancelled or forfeited	(418,006)	7.75
Options outstanding at December 31, 2022	6,748,580	$	6.95	5.0	$	3,307
Options exercisable at December 31, 2022	6,480,492	$	7.11	4.9	$	2,745
Options vested and expected to vest at December 31, 2022	6,769,006	$	6.97	5.0	$	3,256

Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Options at Grant Date

The fair value of employee stock options was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Year Ended December 31,
	2020
Expected term (in years)	6.0
Expected volatility (%)	68.8%
Risk-free interest rate (%)	0.7%
Expected dividend yield (%)	0%

Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Purchases at Grant Date

The fair value of each purchase right granted under the ESPP was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2022	2021	2020
Expected term (in years)	0.50	0.50	0.3 - 0.5
Expected volatility (%)	83.2% - 83.8%	84.2% - 86.0%	83.0%
Risk-free interest rate (%)	0.22% - 2.52%	0.05% - 0.09%	0.09% - 0.17%
Expected dividend yield (%)	—%	—%	—%