Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Activity Relating to Restricted Stock Units

The table below summarizes activity relating to restricted stock units:

	Shares
Outstanding as of December 31, 2019		333,243
Granted		393,811
Vested		—
Forfeited		(22,423	)
Outstanding as of March 31, 2020		704,631

Summary of Stock-Based Compensation Expense Recognized

Stock-based compensation expense recognized during the three months ended March 31, 2020 and 2019 was as follows:

	Three Months Ended March 31,
	2020		2019
	(in thousands)
Research and development	$	12,224	$	20,745
Selling, general and administrative		18,886		23,371
	$	31,110	$	44,116

Summary of Stock-Based Compensation Expense by Award Type Recognized

Stock-based compensation expense recognized during the three months ended March 31, 2020 and 2019 by award type was as follows:

	Three Months Ended March 31,
	2020		2019
	(in thousands)
Stock options	$	30,218	$	43,564
Restricted stock units		—		58
Employee stock purchase plan		892		494
	$	31,110	$	44,116

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

The table below 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, 2019		8,163,113		$	106.30		7.75	$	87,972
Granted		770,860			68.90
Exercised		(7,196	)		50.99
Forfeited		(314,812	)		128.21
Outstanding as of March 31, 2020		8,611,965			102.20		7.69	$	7,083
Exercisable as of March 31, 2020		4,253,664			85.18		6.63	$	7,083