Stock Option and Grant Plan

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock Option and Grant Plan

10. Stock Option and Grant Plan

Stock Incentive Plan

General Option Information

A summary of option activity for the three months ended March 31, 2023, is 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, 2022		8,480,950		$	13.19		8.2	$	201,765
Granted		2,105,628		$	32.64
Exercised		(451,298	)	$	6.14			$	11,682
Cancelled or forfeited		(73,655	)	$	11.98
Outstanding at March 31, 2023		10,061,625		$	17.58		8.4	$	127,488
Options exercisable as of March 31, 2023		2,815,243		$	10.46		7.3	$	53,271
Options unvested as of March 31, 2023		7,246,382		$	20.34		8.8	$	74,217
Weighted average grant-date fair value of options granted during the period	$	21.65

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of options exercised during the three months ended March 31, 2023 and 2022 was $11.7 million and zero, respectively.

The total fair value of stock options vested during the three months ended March 31, 2023 and 2022 was $14.7 million and $1.8 million, respectively.

Restricted Stock Unit Activity

A summary of restricted stock unit activity for the three months ended March 31, 2023, is as follows:

	Number of shares			Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2022		740,297		$	20.02
Granted		467,453		$	32.64
Vested		(146,694	)	$	19.76
Forfeited		(5,084	)	$	22.30
Nonvested as of March 31, 2023		1,055,972		$	25.63

Summary of Stock-Based Compensation Expense

Stock-based compensation expense recorded in the condensed consolidated statements of comprehensive income for the three months ended March 31, 2023 and 2022, is as follows:

	Three Months Ended March 31,
	2023		2022
	(in thousands)
Research and development	$	1,891	$	1,125
Selling, general and administrative		5,610		3,267
Total stock-based compensation expense	$	7,501	$	4,392

The Company capitalized stock-based compensation expense of $0.1 million and zero for the three months ended March 31, 2023 and 2022, respectively.

The following table summarizes stock-based compensation by type of award:

	Three Months Ended March 31,
	2023		2022
	(in thousands)
Stock options	$	6,256	$	3,908
Restricted stock units		1,245		484
Total stock-based compensation expense	$	7,501	$	4,392

The following table summarizes unrecognized stock-based compensation expense as of March 31, 2023, by type of awards, and the weighted-average period over which that expense is expected to be recognized. The total unrecognized stock-based compensation expense will be adjusted for actual forfeitures as they occur.

	As of March 31, 2023
	Unrecognized Expense		Weighted-average Recognition Period
	(in thousands)		(in years)
Stock options	$	99,211		3.22
Restricted stock units	$	25,835		3.53