Stock Plans (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Available for Grant

A summary of shares available for grant under the 2021 Plan is as follows:

	Shares Available for Grant
Shares available for grant as of January 1, 2022	2,132,750
Authorized	1,222,649
Granted/Awarded	(2,260,197)
Canceled	340,308
Withheld for taxes	8,436
Shares available for grant as of December 31, 2022	1,443,946
Authorized	1,252,287
Granted/Awarded	(2,758,399)
Canceled	1,322,669
Withheld for taxes	53,999
Shares available for grant as of December 31, 2023	1,314,502

Summary of Stock Option Activity

A summary of stock option activity for the years ended December 31, 2023 and 2022 is set forth below:

	Options Outstanding
	Number of Shares	Weighted-Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)
Balances as of January 1, 2022	3,038,970	$	2.61	8.83
Granted	690,218	$	7.83
Exercised	(157,447)	$	0.03
Canceled	(125,158)	$	6.99
Balances as of December 31, 2022	3,446,583	$	3.61	8.06
Granted	695,225	$	3.85
Exercised	(889,968)	$	0.17
Canceled	(663,075)	$	5.00
Balances as of December 31, 2023	2,588,765	$	4.51	7.17
Vested and exercisable at December 31, 2023	1,623,869	$	4.22	6.28
Vested and expected to vest at December 31, 2023	2,588,765	$	4.51	7.17

Schedule of Employee Stock Purchase Plan

Compensation expense is calculated using the fair value of the employees' purchase rights under the Black-Scholes model, which was estimated using the following assumptions:

	Year Ended December 31,
	2023	2022
Expected term (in years)	0.5	0.5
Expected volatility	63% - 90%	65% - 67%
Weighted average risk-free interest rate	5.36% - 5.43%	1.75% - 4.72%
Fair value of common stock	$4.20 - $8.49	$1.72 - $6.14
Dividend yield	—%	—%

Schedule of Restricted Stock Units

Activity with respect to restricted stock units, or RSUs, was as follows:

	Number of Shares Underlying Outstanding Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested, January 1, 2022	596,085	$	22.06
Granted	1,569,979	$	7.72
Vested	(194,705)	$	22.78
Canceled	(215,150)	$	13.95
Unvested, December 31, 2022	1,756,209	$	10.15
Granted	2,063,174	$	4.77
Vested	(728,986)	$	9.76
Canceled	(659,594)	$	7.14
Unvested, December 31, 2023	2,430,803	$	6.52

Share-based Payment Arrangement, Expensed and Capitalized, Amount

The Company recognized stock-based compensation as follows (in thousands):

	Year Ended December 31,
	2023		2022
Cost of goods sold	$	606	$	518
Research and development	2,749		2,304
Selling, general and administrative	6,203		5,527
Total stock-based compensation	$	9,558	$	8,349

The above stock-based compensation expense related to the following equity-based awards (in thousands):

	Year Ended December 31,
	2023		2022
Stock options and restricted stock units	$	9,271	$	7,949
ESPP	287		400
Total stock-based compensation	$	9,558	$	8,349

Schedule of Employee Stock Options, Valuation Assumptions

The fair value of employee stock options was estimated using the following assumptions for the years ended December 31, 2023 and December 31, 2022:

	Year Ended December 31,
	2023	2022
Expected term (in years)	5.27 - 6.25	5.27 - 6.25
Expected volatility	60% - 63%	50% - 52%
Weighted average risk-free interest rate	3.74% - 3.94%	1.79% - 3.56%
Fair value of common stock	$1.54 - $4.50	$6.30 - $8.15
Dividend yield	—%	—%