Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Summary of Stock Option Activity

The summary of stock option activity for the three months ended March 31, 2022 (in thousands, except share and per share amounts):

	Number of Shares			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		353,263			7.96
Exercised		(51,118	)		3.45
Forfeited		(62,598	)		4.88
Outstanding at March 31, 2022		6,166,516		$	10.02		9.3	$	440
Options exercisable at March 31, 2022		1,202,273		$	5.46		9.0	$	189

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:

	Three Months Ended March 31,
	2022	2021
Expected volatility	98.05% - 101.66%	75.17%
Risk-free interest rate	1.60%	1.16%
Expected dividend yield	0.00%	0.00%
Expected term (in years)	6.08	6.02 – 6.08

Summary of Stock-Based Compensation Expense

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

	Three Months Ended March 31,
	2022		2021
Research and development	$	472	$	820
General and administrative		2,874		1,624
Total	$	3,346	$	2,444

Summary of Restricted Stock Activity

The summary of restricted stock activity for the three months ended March 31, 2022:

	Number of Shares			Weighted Average Grant Date Fair Value
Non-vested at December 31, 2021		618,494		$	3.04
Granted		2,082,952			4.07
Vested		(100,908	)		0.01
Non-vested at March 31, 2022		2,600,538		$	4.06