Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

During the three months ended March 31, 2022 and 2021, the Company recognized the following stock-based compensation expense (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	14,589	$	12,845
General and administrative		11,156		9,247
Total	$	25,745	$	22,092

Summary of Stock Option Activity

The following table summarizes stock option activity for the three months ended March 31, 2022:

	Shares			Weighted- average exercise price per share
Outstanding at December 31, 2021		7,812,982		$	58.07
Granted		820,189			58.62
Exercised		(261,280	)		39.17
Cancelled or forfeited		(151,433	)		78.48
Outstanding at March 31, 2022		8,220,458		$	58.35
Exercisable at March 31, 2022		4,757,990		$	43.59
Vested and expected to vest at March 31, 2022		8,220,458		$	58.35

Summary of Restricted Stock Activity

The following table summarizes restricted stock activity for the three months ended March 31, 2022:

	Restricted Stock			Weighted- Average Grant Date Fair Value
Unvested balance as of December 31, 2021		934,175		$	100.14
Granted		361,896			58.55
Vested		(123,564	)		83.94
Cancelled or forfeited		(25,143	)		109.89
Unvested balance as of March 31, 2022		1,147,364		$	88.56