Stock-Based Awards (Tables)

12 Months Ended

Dec. 31, 2023

Stock-Based Awards

Assumptions used to determine fair value of stock options granted

	Year Ended
	December 31,
	2023		2022		2021
Risk-free interest rate	3.55	%	2.22	%	0.92	%
Expected term (in years)	6.2		6.2		6.2
Expected volatility	77.73	%	77.95	%	76.60	%
Expected dividend yield	0	%	0	%	0	%

Summary of stock option activity

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number	Exercise		Contractual	Intrinsic
(In thousands, except share and per share data and years)	of Shares	Price		Term	Value
				(in years)
Outstanding as of December 31, 2020	2,871,498	$	15.16	6.8	$	4,890
Granted	1,068,100		23.44
Exercised	(115,548)		12.63			1,373
Forfeited and cancelled	(31,600)		23.26
Outstanding as of December 31, 2021	3,792,450	$	17.50	6.8	$	13,710
Granted	2,548,750		14.40
Exercised	(88,172)		1.78			1,120
Forfeited and cancelled	(1,085,864)		18.44
Outstanding as of December 31, 2022	5,167,164	$	16.04	7.2	$	15,288
Granted	2,241,550		15.62
Exercised	(71,092)		1.31			473
Forfeited and cancelled	(918,167)		16.85
Outstanding as of December 31, 2023	6,419,455	$	15.94	7.1	$	14
Options vested and expected to vest as of December 31, 2023	6,419,455	$	15.94	7.1	$	14
Options exercisable as of December 31, 2023	2,879,529	$	16.55	5.1	$	14

Summary of restricted stock units activity

		Weighted
		Average
		Grant Date		Aggregate
	Number	Fair Value		Intrinsic
(In thousands, except share and per share data)	of Shares	Per Share		Value
Outstanding as of December 31, 2020	2,244,157	$	3.83
Granted	664,948		23.33
Vested	(1,340,042)		3.18	$	31,492
Forfeited and cancelled	(72,117)		10.36
Outstanding as of December 31, 2021	1,496,946	$	12.75
Granted	936,563		14.43
Vested	(533,212)		11.61	$	7,943
Forfeited and cancelled	(379,567)		13.40
Outstanding as of December 31, 2022	1,520,730	$	14.02
Granted	993,662		15.17
Vested	(745,279)		11.72	$	8,262
Forfeited and cancelled	(247,173)		15.15
Outstanding as of December 31, 2023	1,521,940	$	15.72

Stock-based compensation expense

	Year Ended
	December 31,
(In thousands)	2023		2022		2021
Cost of revenue	$	1,456	$	1,151	$	981
Research and development		6,801		3,745		3,866
General and administrative		12,285		10,143		9,213
Total stock-based compensation expense	$	20,542	$	15,039	$	14,060