Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-Based Compensation Expense Recorded in Statements of Operations

The Company recorded stock-based compensation expense in the following expense categories in its accompanying statements of operations:

	Year Ended December 31,
(in thousands)	2021		2020
Research and development	$	9,469	$	2,585
General and administrative		11,462		2,998
	$	20,931	$	5,583

Summary of Stock Option Activity

The following table summarizes stock option activity for the Plan in the years indicated:

	Number of shares			Weighted average exercise price per share		Weighted average remaining contractual term (years)
Outstanding at January 1, 2020		2,269,742		$	1.66		9.20
Granted		4,785,630		$	11.35
Exercised		(100,545	)	$	0.99
Forfeited		(115,736	)	$	1.37
Outstanding at December 31, 2020		6,839,091		$	8.46		9.17
Granted		2,600,231		$	31.14
Exercised		(995,950	)	$	3.52
Forfeited		(1,263,890	)	$	19.79
Outstanding at December 31, 2021		7,179,482		$	15.36		8.66
Exercisable at December 31, 2021		2,057,975		$	6.99		8.04

Summary of Information about Stock Options Outstanding

The following table summarizes information about stock options outstanding and exercisable at December 31, 2021 under the Plan:

	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life (in years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$0.31 - $7.37		2,352,647		7.76	$	1.80		1,233,638	$	1.75
$7.38 - $13.08		2,465,488		8.67		12.85		777,587		12.85
$13.09 - $31.30		1,760,632		9.61		27.58		4,219		17.99
$31.31 - $88.98		600,715		9.35		43.02		42,531		50.79
		7,179,482						2,057,975

Schedule of Fair Value of Each Option Estimated on Date of Grant Using Weighted Average Assumptions

The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below:

	Year Ended December 31,
	2021			2020
Expected volatility		87.46	%		115.17	%
Risk-free interest rate		0.94	%		0.43	%
Expected life (in years)		6.04			6.25
Expected dividend yield		—			—

Summary of Activity related to RSA Stock-Based Payment Awards

The following table summarizes activity related to RSA stock-based payment awards:

	Number of shares			Weighted- average grant date fair value
Unvested balance at January 1, 2020		1,335,349		$	1.42
Granted		432,301		$	3.26
Vested		(552,883	)	$	1.37
Unvested balance at December 31, 2020		1,214,767		$	2.09
Vested		(603,159	)	$	1.89
Unvested balance at December 31, 2021		611,608		$	2.29

Summary of Activity related to RSU Stock-Based Payment Awards

The following table summarizes activity related to RSU stock-based payment awards:

	Number of shares			Weighted- average grant date fair value
Outstanding at January 1, 2021		—
Granted		45,000		$	26.91
Forfeited		(25,000	)	$	33.78
Outstanding at December 31, 2021		20,000		$	18.32