Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Summary of stock options and performance-based stock options under 2021 LTPIP, 2018 Plan and 2015 Plan.

Stock option activity, including stock options and performance-based stock options under the 2021 Long-Term Performance Incentive Plan (“2021 LTPIP”), 2018 Plan and 2015 Plan is summarized as follows:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		14,523,917		$	61.68		8.60	$	335,440
Granted		388,820		$	14.74
Exercised		(110,363	)	$	15.22
Forfeited or canceled		(563,036	)	$	81.32
Outstanding at June 30, 2022		14,239,338		$	59.99		8.09	$	6,444

Summary of Restricted Shares

Restricted share activity, including restricted stock awards, restricted stock units, and performance-based restricted stock units, under the 2018 Plan and 2015 Plan is summarized as follows:

	Number of Restricted Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2021		363,930		$	72.75
Granted		44,250			27.38
Vested		(77,729	)		69.50
Canceled		(37,688	)		74.65
Unvested at June 30, 2022		292,763		$	66.51

Summary of Stock-based Compensation for Options and Restricted Shares Classified in Condensed Consolidated Statements of Operations and Comprehensive Loss

Stock-based compensation for options, restricted shares, and ESPP is classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2022		2021		2022		2021
Research and development	$	14,109	$	5,770	$	30,084	$	11,169
General and administrative		11,869		5,317		23,989		9,843
Total stock-based compensation	$	25,978	$	11,087	$	54,073	$	21,012