Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Stock-Based Compensation

Schedule of stock option activity

		Weighted		Weighted
		Average		Average
		Exercise		Remaining
		Price		Contractual
	Shares	Per Share		Term (In Years)
Options outstanding at December 31, 2021	4,077,667	$	30.02	8.0
Granted	1,620,000	$	23.19	—
Exercised	(458,254)	$	8.22	—
Canceled	(153,751)	$	48.36	—
Options outstanding at December 31, 2022	5,085,662	$	29.26	7.9
Options vested and expected to vest at December 31, 2022	4,970,769	$	29.40	7.8
Options exercisable at December 31, 2022	2,100,491	$	40.05	6.6
Shares available for grant under the 2021 Plan	1,837,968		—	—

Schedule of stock-based compensation expense

	2022		2021		2020
	(In thousands)
Research and development	$	8,082	$	4,525	$	1,933
General and administrative		7,529		4,428		1,982
Total stock-based compensation expense	$	15,611	$	8,953	$	3,915

Schedule of assumptions used for the fair value of employee stock options granted

	2022	2021	2020
Expected stock price volatility	90 - 97%	97 - 98%	91 - 98%
Expected option term	6.0 Years	6.0 Years	6.0 Years
Risk-free interest rate	1.7 - 4.2%	0.8 - 1.4%	0.5 - 0.7%
Expected dividend yield	None	None	None