Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense for stock options and RSUs is reflected in the consolidated statements of operations and comprehensive loss as follows (in thousands):

	Year ended December 31,
	2023		2022
General and administrative	$	6,876	$	7,777
Research and development	2,341		2,764
Total	$	9,217	$	10,541

Schedule of Weighted Average Assumptions Utilized in Fair Value

The assumptions utilized in the fair value calculations for stock options as of December 31, 2023 and 2022 were as follows:

	Year ended December 31,
	2023	2022
Weighted average expected option term (years)	5.9	5.9
Range of expected stock price volatility	103% – 109%	106% – 110%
Weighted average expected stock price volatility	106%	107%
Range of risk-free interest rate	3.5% – 4.4%	1.4% – 4.2%
Expected dividend rate	0%	0%

Schedule of Stock Option Activity

The following table summarizes the stock option activity:

	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (In Thousands)
Options outstanding at December 31, 2022	10,851,287	$	2.95	8.30	$	1,385
Granted	5,042,621	1.03			2
Exercised	(295,000)	0.40			168
Forfeited	(2,437,680)	2.37			9
Options outstanding at December 31, 2023	13,161,228	$	2.38	7.86	$	337
Options exercisable at December 31, 2023	6,578,928	$	2.74	7.12	$	204

Schedule of RSU Activity

The following table summarizes the RSU activity:

	Number of Shares	Weighted Average Grant-Date Fair Value		Aggregate Intrinsic Value (In Thousands)
RSUs outstanding at December 31, 2022	924,810	$	4.12	$	1,202
Granted	3,389,933	1.15		3,910
Vested	(281,119)	4.31		299
Forfeited	(1,050,963)	1.55		651
RSUs outstanding at December 31, 2023	2,982,661	$	1.63	$	1,715