Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-based Payment Arrangement [Abstract]

Summary of stock option activity

The following table summarizes stock option activity during the twelve months ended December 31, 2022:

	Shares			Weighted average exercise price		Weighted average remaining contractual life (years)		Aggregate intrinsic value (in thousands)
Outstanding at January 1, 2022		2,301,574		$	78.90
Options granted		860,795			81.39
Options exercised		(215,784	)		41.50
Options cancelled		(89,531	)		100.71
Outstanding at December 31, 2022		2,857,054		$	81.78		6.49	$	596,279
Exercisable at December 31, 2022		1,610,185		$	76.31		4.90	$	345,162

Schedule of stock-based compensation expense

Stock-based compensation expense during the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):

	Year Ended December 31,
	2022		2021		2020
Stock-based compensation expense by type of award:
Stock options	$	31,625	$	26,873	$	20,730
Total stock-based compensation expense	$	31,625	$	26,873	$	20,730
Effect of stock-based compensation expense by line item:
Research and development	$	13,876	$	10,698	$	8,833
General and administrative		17,749		16,175		11,897
Total stock-based compensation expense included in net loss	$	31,625	$	26,873	$	20,730