Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Stock Option Activity

The following table summarizes stock option activity under all equity plans (excluding RSUs) during the three months ended March 31, 2024:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2023		2,865,594		$	10.89		5.76	$	1
Granted		35,604			1.52
Exercised		—			—
Forfeited or cancelled		(20,135	)		13.66
Outstanding as of March 31, 2024		2,881,063		$	10.75		5.51	$	8
Outstanding as of March 31, 2024 - vested and    expected to vest		2,881,063		$	10.75		5.51	$	8
Exercisable at March 31, 2024		2,488,009		$	10.37		5.22	$	2

Summary of Share-Based Compensation Expense

The Company recorded share-based compensation expense related to incentive stock options, nonqualified stock options, stock grants, and stock-based awards in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands):

	Three Months Ended March 31,
	2024		2023
Research and development expenses	$	690	$	798
General and administrative expenses		1,333		1,372
Total	$	2,023	$	2,170

Restricted Stock Units (RSUs) [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Activity of Options and RSUs of Performance-Based Options

The following table summarizes RSU activity under all equity plans during the three months ended March 31, 2024:

	Number of RSU Shares			Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2023		5,368,807		$	2.45
Granted		3,123,496			1.57
Vested and released		(869,459	)		2.73
Forfeited or cancelled		(149,600	)		1.93
Outstanding as of March 31, 2024		7,473,244		$	2.06

Performance Shares [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Activity of Options and RSUs of Performance-Based Options

The following table summarizes Inducement PSU activity under all equity plans during the three months ended March 31, 2024:

	Number of Inducement PSU Shares		Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2023		69,999	$	1.08
Granted		—		—
Vested and released		—		—
Forfeited or cancelled		—		—
Outstanding as of March 31, 2024		69,999	$	1.08