Stock-Based Compensation

3 Months Ended

Mar. 31, 2022

Stock-Based Compensation

Stock-Based Compensation

(8)  Stock-Based Compensation

A summary of stock option activity for the three months ended March 31, 2022 is as follows:

		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

The weighted average grant-date fair value of stock options granted during the three ended March 31, 2022 was $24.63.

The aggregate intrinsic value of stock options vested and expected to vest at March 31, 2022 was $65.9 million. The aggregate intrinsic value of stock options exercisable at March 31, 2022 was $32.0 million. As of March 31, 2022, total compensation cost related to non-vested employee, consultant and non-employee director stock options not yet recognized was approximately $29.5 million, net of estimated forfeitures, which is expected to be recognized as expense over a weighted average period of 2.6 years.

Stock-based compensation expense for the three months ended March 31, 2022 and 2021 was recorded as follows:

	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

The fair values of employee, consultant and non-employee director stock options granted during the three months ended March 31, 2022 and 2021 were valued using the Black-Scholes option pricing model with the following assumptions:

	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