Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Total Stock-Based Compensation Expense

Total stock-based compensation expense recorded as research and development and general and administrative expenses, respectively, for employees, directors and non-employees for the periods presented is as follows (in thousands):

	THREE MONTHS ENDED SEPTEMBER 30,				NINE MONTHS ENDED SEPTEMBER 30,
	2023		2022		2023		2022
Research and development	$	—	$	886	$	231	$	2,655
General and administrative		335		1,215		1,584		3,396
Total	$	335	$	2,101	$	1,815	$	6,051

Restricted Stock Units (RSUs) [Member]

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Activity of Stock Options

The following table summarizes the activity of the Company’s RSUs under the 2021 Plan for the nine months ended September 30, 2023:

	RSUs			WEIGHTED- AVERAGE GRANT DATE FAIR VALUE		AGGREGATE INTRINSIC VALUE (in thousands)
Outstanding as of December 31, 2022		9,039		$	83.88	$	131
Vested and distributed		(3,317	)	$	83.80
Forfeited		(5,722	)	$	83.93
Unvested as of September 30, 2023		—		$	—	$	—

Stock Options [Member]

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Activity of Stock Options

The following table summarizes the activity of the Company’s stock options under the 2017 Plan and 2021 Plan for the nine months ended September 30, 2023:

	SHARES			WEIGHTED- AVERAGE EXERCISE PRICE		WEIGHTED- AVERAGE REMAINING CONTRACTUAL TERM (in years)		AGGREGATE INTRINSIC VALUE (in thousands)
Outstanding as of December 31, 2022		109,522		$	293.81		6.9	$	—
Granted		34,094		$	8.15
Cancelled or forfeited		(48,146	)	$	327.08
Expired		(37,666	)	$	328.80
Outstanding as of September 30, 2023		57,804		$	75.09		7.3	$	13
Options exercisable as of September 30, 2023		22,573		$	155.59		4.3	$	—
Options vested or expected to vest as of September 30, 2023		57,804		$	75.09		7.3	$	13