Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

Schedule of Share Based Compensation Available for Grant under Incentive Plans

The number of shares available for grant under the Company’s incentive plans were as follows:

	New			Inducement
	Plan			Plan			Total
Available for grant - January 1, 2024		3,162,725			4,000,000			7,162,725
Plan adjustments and amendments		9,348,009			—			9,348,009
Grants		(11,314,622	)		(784,700	)		(12,099,322	)
Forfeitures		120,227			—			120,227
Available for grant - March 31, 2024		1,316,339			3,215,300			4,531,639

Schedule of Restricted Stock Units Activity

The Company’s RSU activity for the three months ended March 31, 2024 was as follows:

				Weighted
				Average
				Grant Date
	Number			Fair Value
	of Shares			per Share
Nonvested at January 1, 2024		375,044		$	6.63
Restricted units granted		4,300,261			1.77
Vested		(17,334	)		1.18
Cancelled or forfeited		—			—
Nonvested at March 31, 2024		4,657,971		$	7.50

Schedule of Total Stock-Based Compensation Expense for Stock Options, ESPP, RSAs and RSUs

The following table summarizes the total stock-based compensation expense for the stock options, ESPP, RSAs and RSUs recorded in the condensed consolidated statements of operations for the three months ended March 31, 2024 and 2023 (in thousands):

	For the Three Months Ended March 31,
	2024		2023
Research and development expense	$	1,273	$	(263	)
General and administrative expense		1,925		1,938
Total	$	3,198	$	1,675

Stock Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following weighted-average assumptions were used to estimate the fair value of time-based vesting stock options that were granted during the three months ended March 31, 2024 and 2023:

	Three Months Ended March 31,
	2024			2023
Risk-free interest rate		3.95	%		3.46	%
Expected dividend yield		—			—
Expected term (in years)		6.1			6.1
Expected volatility		89	%		81	%

Schedule of Stock Option Activity

The following table summarizes time-based vesting stock option activity, during the three months ended March 31, 2024:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Stock			Exercise		Contractual		Value
	Options			Price		Life (in years)		(in thousands)
Outstanding at January 1, 2024		5,960,922		$	5.75		8.7	$	1,960
Options granted		7,799,061			1.78
Options cancelled or forfeited		(53,037	)		2.65
Options expired		(61,138	)		17.79
Outstanding at March 31, 2024		13,645,808		$	3.44		9.2	$	14,289
Options exercisable at March 31, 2024		1,948,590		$	11.39		7.8	$	763

Performance Stock Options | Initial Options and Original Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following weighted-average assumptions were used to estimate the fair value of the options granted in February 2023 and the Original Options that were granted in May 2023:

Risk-free interest rate	4.02	%
Expected dividend yield	—
Expected term (in years)	6.0
Expected volatility	81	%

Performance Stock Options | Modified Options

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

The following assumptions were used to estimate the fair value of the Modified Options:

Risk-free interest rate	3.90	%
Expected dividend yield	—
Expected term (in years)	5.8
Expected volatility	88	%