Stock-Based Compensation (Tables)

3 Months Ended

Mar. 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	19,500	$	31.94
Exercised	(19,555)	$	8.68
Canceled	(13,055)	$	26.26
Options outstanding at March 31, 2022	4,064,557	$	30.14	7.8
Options vested and expected to vest at March 31, 2022	3,977,784	$	30.33	7.8
Options exercisable at March 31, 2022	1,619,025	$	45.51	6.4
Shares available for grant under the 2021 Plan	3,297,772

Schedule of stock-based compensation expense

	Three months ended March 31,
	2022		2021
	(In thousands)
Research and development	$	1,614	$	661
General and administrative		1,539		614
Total stock-based compensation expense	$	3,153	$	1,275

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

	Three months ended March 31,
	2022	2021
Expected stock price volatility	91 – 97%	97 – 98%
Expected option term	6.0 Years	6.0 Years
Risk-free interest rate	1.7 – 1.9%	0.8 – 1.2%
Expected dividend yield	None	None