Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of stock-based compensation expense

Stock-Based Compensation Expense

Stock-based compensation expense recorded in research and development expense and general and administrative expense for the three and six months ended June 30, 2022 and 2021 was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2022		2021		2022		2021
General and administrative	$	1,351	$	2,647	$	2,809	$	4,517
Research and development		833		1,608		1,577		3,003
Total stock-based compensation expense	$	2,184	$	4,255	$	4,386	$	7,520

Stock-based compensation expense by award type for the three and six months ended June 30, 2022 and 2021 was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2022		2021		2022		2021
Stock options	$	2,184	$	1,253	$	4,386	$	1,513
Restricted stock awards		—		3,002		—		6,007
Total stock-based compensation expense	$	2,184	$	4,255	$	4,386	$	7,520

Schedule of outstanding common stock options and related activity

Outstanding stock options and related activity for the six months ended June 30, 2022 was as follows:

(in thousands, except share, per share, and term data)	Number of Options			Weighted Average Exercise Price Per Share		Weighted Average Remaining Term (Years)		Intrinsic Value
Outstanding - December 31, 2021		10,395,027			3.35		6.32		21,082
Granted		2,755,973			3.01		9.65		—
Exercised		(1,044,448	)		0.27		—		2,348
Forfeited		(35,276	)		5.07		—		—
Outstanding - June 30, 2022		12,071,276		$	3.54		6.97	$	8,718
Vested and exercisable - June 30, 2022		6,161,852		$	2.10		4.84	$	8,711
Vested, exercisable or expected to vest - June 30, 2022		12,071,276		$	3.54		6.97	$	8,718

Schedule of assumptions used to calculate the fair value of stock options

The assumptions used to calculate the fair value of stock options granted during the six months ended June 30, 2022 and 2021 were as follows:

	Six Months Ended June 30,
	2022	2021
Expected stock price volatility	89.57% – 93.38%	84.80% – 87.70%
Risk-free interest rate	1.65% – 3.00%	0.59% – 1.90%
Expected dividend yield	0.00%	0.00%
Expected term of options	5.00 – 6.98 years	6.00 years

Schedule of restricted common stock activity

Outstanding rights to restricted stock awards and related activity for the six months ended June 30, 2022 was as follows:

	Number of Restricted Stock Awards			Weighted Average Grant Date Fair Value
Unvested balance as of December 31, 2021		916,603		$	10.00
Converted to shares of Common Stock upon vesting		(65,363	)		—
Forfeited		(2,025	)		9.84
Unvested balance as of June 30, 2022		849,215		$	9.93