Stock Incentive Plan (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Summary of Stock Option Activity

The following table summarizes stock option activity under the stock incentive plans since December 31, 2021:

		Number of Options			Weighted- Average Exercise Price (per Share)		Weighted- Average Remaining Contract Term (in Years)
Outstanding at December 31, 2021			5,322,314		$	6.75
Exercisable at December 31, 2021			3,296,183			3.03
	Granted		4,001,890			7.56
	Exercised		(65,399	)		0.62
	Canceled or forfeited		(119,461	)		17.83
Outstanding at March 31, 2022			9,139,344			7.00		9.01
Exercisable at March 31, 2022			3,365,635			3.08		7.81

Summary of Equity Based Compensation Expense

The classification of stock-based compensation expense is summarized as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	909	$	225
Selling, general and administrative		2,657		871
Total stock-based compensation expense	$	3,566	$	1,096

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following table shows the weighted-average assumptions used to compute the fair value of the awards granted to employees and nonemployees using the Black-Scholes option pricing model during the periods below:

	Three Months Ended March 31,
Assumption	2022	2021
Expected volatility	56.87%	82.50%
Expected term (years)	5.8−6.1	6.0−6.1
Expected dividend yield	0.00%	0.00%
Risk-free interest rate	1.67%	0.87%
Forfeiture rate	0.00%	0.00%

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following as of March 31, 2022:

Stock options issued and outstanding under all Plans	9,139,344
Authorized for future grants under the 2021 Plan	7,006,507
Authorized for future grants under the ESPP	1,394,991
Total as of March 31, 2022	17,540,842