Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-based Payment Arrangement [Abstract]

Summary of Stock-based Compensation Expense

Stock-based compensation expense is as follows (in thousands):

	Three-months Ended June 30,
	2022		2021
General and administrative expense	$	418	$	444
Research and development	777		1,774
Total	$	1,195	$	2,218

	Six-months Ended June 30,
	2022		2021
General and administrative expense	$	2,191	$	617
Research and development	4,069		2,418
Total	6,260		3,035

Summary of Stock Option Activity

The following table summarizes option activity under the Plan:

	Options	Weighted Average Exercise Price	Weighted Average Contractual Term (in Years)
Balance as of December 31, 2021	17,695,560	1.44	5.6
Granted	261,300	11.87
Exercised	(144,313)	2.65
Forfeited	(221,354)	11.50
Balance as of June 30, 2022	17,591,193	1.46	5.2

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

The fair value of each stock option grant under the Plan was estimated on the date of grant using the Black-Scholes option pricing model, with the following range of assumptions:

	Six-months Ended June 30, 2022
Expected term (in years)	6.3
Volatility	79.7% to 81.4%
Dividend yield	0.0%
Risk-free interest rate	2.82% to 3.26%
Common stock price	$9.03 to $12.24

Schedule of RSU Activity

The following table summarizes RSU activity under the Plan:

	RSU Awards	Weighted Average Grant Date Fair Value
Unvested as of December 31, 2021	17,174	$	13.47
Awarded	372,484	10.67
Vested	(376,890)	11.38
Forfeited	(1,016)	11.46
Unvested as of June 30, 2022	11,752	$	12.72