Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock Based Compensation Expense Recognized

Stock-based compensation expense is recognized in the statements of operations as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(in thousands)
Research and development	$	7,437	$	4,072	$	20,557	$	9,888
General and administrative		2,643		1,878		7,189		5,161
Total stock-based compensation expense	$	10,080	$	5,950	$	27,746	$	15,049

Schedule of Unrecognized Stock-Based Compensation Costs Related to Unvested Awards and Weighted-Average Period Over Which Costs are Expected to be Recognized

Unrecognized stock-based compensation costs related to unvested awards and the weighted-average period over which the costs are expected to be recognized as of September 30, 2022 are as follows:

	Stock Options		RSAs		RSUs
Unrecognized stock-based compensation expense (in thousands)	$	92,582	$	860	$	5,317
Weighted-average period costs expected to be recognized (in years)		2.8		1.0		2.5

Summary of Stock Option Activity

A summary of the Company’s stock option activity is as follows:

	Stock Options (in thousands)			Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2021		17,337		$	8.96		8.7	$	141,718
Granted		11,375			6.15
Exercised		(983	)		2.16
Forfeited/Cancelled		(2,187	)		8.53
Outstanding as of September 30, 2022		25,542		$	8.00		8.6	$	24,279
Exercisable as of September 30, 2022		6,604		$	6.90		7.8	$	13,114

Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Estimating Fair Value of Stock Options Granted

The fair value of stock options granted to employees, directors, and consultants was estimated on the date of grant using the Black-Scholes option pricing model using the following assumptions:

	Nine Months Ended September 30,
Assumptions	2022	2021
Risk free interest rate	1.56% - 3.94%	0.46% - 1.15%
Expected volatility	70%	70%
Expected term (years)	5.50 - 6.25	5.50 - 6.40
Expected dividend	0%	0%

Summary of Additional Information Related to Stock Option Activity

The following table summarizes additional information related to stock option activity:

	Nine Months Ended September 30,
	2022		2021
Weighted average grant date fair value per share for options granted	$	3.96	$	14.64
Aggregate intrinsic value of stock options exercised (in thousands)	$	5,854	$	22,187

Summary of RSA Activity

A summary of the Company’s restricted stock activity is as follows:

	RSAs (in thousands)			RSAs Weighted-Average Grant Date Fair Value per Share		RSUs (in thousands)			RSUs Weighted-Average Grant Date Fair Value per Share
Unvested shares as of December 31, 2021		4,365		$	0.43		141		$	9.43
Granted		-			-		983			6.33
Vested		(3,530	)		0.28		(59	)		8.56
Forfeited		(29	)		-		(88	)		4.66
Unvested shares as of September 30, 2022		806		$	1.13		977		$	6.82