Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Activity Relating to Restricted Stock Units

The following table summarizes activity relating to time-based restricted stock units and performance restricted stock units:

	Shares			Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2021		1,256,098		$	57.87
Granted		705,380			40.02
Vested		(366,014	)		40.13
Forfeited		(179,983	)		95.84
Outstanding as of December 31, 2022		1,415,481			48.73

Summary of Activity Relating to Time Based and Performance Based Stock Options

The following table summarizes activity related to time-based and performance-based stock options:

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2021		7,283,439		$	84.17		6.74	$	16,590
Granted		1,181,487		$	39.45
Exercised		(156,195	)	$	7.84
Forfeited		(520,381	)	$	98.65
Outstanding as of December 31, 2022		7,788,350		$	77.95		6.36	$	7,275
Vested and expected to vest as of December 31, 2022		6,724,505		$	78.86		6.05	$	6,917
Exercisable as of December 31, 2022		5,109,027		$	85.76		5.22	$	5,607

Summary of Stock-Based Compensation Expense Recognized

The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2022, 2021 and 2020:

	Year Ended December 31,
	2022		2021		2020
	(in thousands)
Research and development	$	25,888	$	49,746	$	42,370
Selling, general and administrative		35,714		54,883		51,836
Restructuring		—		—		1,788
	$	61,602	$	104,629	$	95,994

Summary of Stock-Based Compensation Expense by Award Type

The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2022, 2021 and 2020:

	Year Ended December 31,
	2022		2021		2020
	(in thousands)
Stock options	$	54,971	$	78,516	$	90,064
Restricted stock units		5,587		25,375		4,904
Employee stock purchase plan		1,044		738		1,026
	$	61,602	$	104,629	$	95,994

Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted

The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions:

	Year Ended December 31,
	2022			2021			2020
Expected dividend yield		0	%		0	%		0	%
Expected volatility		73	%		76	%		78	%
Risk-free interest rate		2.49	%		0.63	%		0.97	%
Expected term	6.03 years			5.92 years			5.98 years