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 for the year ended December 31, 2022 (in thousands, except share and per share amounts):

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding at January 1, 2022		5,926,969		$	10.03		9.5	$	16,414
Granted		1,178,280			4.06
Exercised		(73,841	)		2.48
Forfeited		(834,095	)		7.24
Expired		(476,898	)		5.51
Outstanding at December 31, 2022		5,720,415		$	9.68		8.8	$	72
Options exercisable at December 31, 2022		2,037,934		$	9.34		8.5	$	59

Schedule of Estimated Fair Value Assumptions

The Company estimated the fair value of each option on the date of grant using the Black-Scholes option-pricing model applying the range of assumptions in the following table:

	Year Ended December 31,
	2022	2021
Expected volatility	96.09% - 101.66%	72.88% - 103.41%
Risk-free interest rate	1.60% - 4.02%	0.81% - 1.36%
Expected dividend yield	0.00%	0.00%
Expected term (in years)	6.00 - 6.11	5.25 - 7.00

Summary of Stock-Based Compensation Expense

Stock-based compensation expense related to stock options recorded in the statements of operations is as follows (in thousands):

	Year Ended December 31,
	2022		2021
Research and development	$	4,330	$	2,396
General and administrative		7,617		3,976
Total	$	11,947	$	6,372

Summary of Restricted Stock Activity

The following table summarizes restricted stock activity for the year ended December 31, 2022:

	Number of Shares			Weighted Average Grant Date Fair Value
Non-vested at December 31, 2021		618,494		$	3.04
Granted		3,174,656			3.69
Vested and settled		(432,354	)		0.55
Forfeited		(345,409	)		3.74
Non-vested and unsettled at December 31, 2022		3,015,387		$	3.64