Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 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	1,570,900	$	22.79
Exercised	(29,910)	$	8.05
Canceled	(28,444)	$	36.24
Options outstanding at June 30, 2022	5,590,213	$	28.07	8.20
Options vested and expected to vest at June 30, 2022	5,428,921	$	28.25	8.17
Options exercisable at June 30, 2022	2,135,506	$	39.84	6.76
Shares available for grant under the 2021 Plan	1,761,761

Schedule of stock-based compensation expense

	Three months ended June 30,				Six months ended June 30,
	2022		2021		2022		2021
	(In thousands)				(In thousands)
Research and development	$	1,798	$	762	$	3,412	$	1,423
General and administrative		1,656		747		3,195		1,361
Total stock-based compensation expense	$	3,454	$	1,509	$	6,607	$	2,784

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

	Three months ended June 30,		Six months ended June 30,
	2022	2021	2022	2021
Expected stock price volatility	90 – 91%	97 – 98%	90 – 97%	97 – 98%
Expected option term	6.0 Years	6.0 Years	6.0 Years	6.0 Years
Risk-free interest rate	2.7 – 3.6%	1.2 – 1.3%	1.7 – 3.6%	0.8 – 1.3%
Expected dividend yield	None	None	None	None