Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

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:

	Existing			New
	Plan			Plan			Total
Available for grant - January 1, 2021		—			2,941,509			2,941,509
Plan adjustments and amendments		(250,778	)		1,685,712			1,434,934
Grants		—			(3,192,600	)		(3,192,600	)
Forfeitures		250,778			217,480			468,258
Available for grant - December 31, 2021		—			1,652,101			1,652,101
Plan adjustments and amendments		—			1,923,697			1,923,697
Grants		—			(4,775,676	)		(4,775,676	)
Forfeitures		—			2,267,560			2,267,560
Available for grant - December 31, 2022		—			1,067,682			1,067,682

Schedule of Restricted Stock Units Activity

The Company’s RSU activity for the year ended December 31, 2022 and 2021 was as follows:

				Weighted
				Average
				Grant Date
	Number			Fair Value
	of Shares			per Share
Nonvested at January 1, 2021		2,850,053		$	6.37
Restricted units granted		—			—
Vested		(712,510	)		6.37
Cancelled or forfeited		(250,778	)		5.25
Nonvested at December 31, 2021		1,886,765		$	6.52
Restricted units granted		—			—
Vested		(628,921	)		6.52
Cancelled or forfeited		—			—
Nonvested at December 31, 2022		1,257,844		$	6.52

Schedule of Restricted Stock Awards Activity

The Company’s RSA activity for the year ended December 31, 2022 and 2021 was as follows:

				Weighted
				Average
				Grant Date
	Number			Fair Value
	of Shares			per Share
Nonvested at January 1, 2021		769,058		$	5.28
Restricted stock granted		—			—
Vested		(427,083	)		5.28
Nonvested at December 31, 2021		341,975		$	5.28
Restricted stock granted		—			—
Vested		(256,481	)		5.28
Nonvested at December 31, 2022		85,494		$	5.28

Schedule of Total Remaining Stock-Based Compensation Expense for Stock Options, RSAs and RSUs (Detail)

The following table summarizes the total remaining stock-based compensation expense for the stock options, RSAs and RSUs recorded in the consolidated statements of operations for the years ended December 31, 2022 and 2021 (in thousands):

	For the Year Ended December 31,
	2022		2021
Research and development expense	$	7,608	$	8,286
General and administrative expense		10,435		9,898
Total	$	18,043	$	18,184

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 stock options granted during the years ended December 31, 2022 and 2021:

	Year Ended December 31,
	2022			2021
Risk-free interest rate		2.95	%		0.84	%
Expected dividend yield		—			—
Expected term (in years)		6.1			6.0
Expected volatility		78	%		75	%

Schedule of Stock Option Activity

The following table summarizes stock option activity during the years ended December 31, 2022 and 2021:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Stock			Exercise		Contractual		Value
	Options			Price		Life (in years)		(in thousands)
Outstanding at January 1, 2021		674,842		$	20.68		9.8	$	3,953
Options granted		3,192,600			24.99		—		—
Options cancelled or forfeited		(217,480	)		26.07		—		—
Outstanding at December 31, 2021		3,649,962		$	24.13		9.2	$	—
Options granted		4,775,676			4.48		—		—
Options cancelled or forfeited		(2,048,192	)		15.25		—		—
Options expired		(219,368	)		24.36		—		—
Outstanding at December 31, 2022		6,158,078		$	11.84		8.9	$	62
Options exercisable at December 31, 2022		1,225,613		$	24.88		7.3	$	—