Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2022

Equity [Abstract]

Summary of Unvested Shares and Unvested Stock Liability

A summary of the Company’s unvested shares and unvested stock liability is as follows (in thousands, except share data):

	Number of Unvested Shares			Unvested Stock Liability
Balance at December 31, 2021		2,132		$	3
Vested shares		(2,132	)		(3	)
Balance at March 31, 2022		—		$	—

Summary of Stock Option Activity

A summary of the Company’s stock option activity is as follows (in thousands, except share and per share data):

	Number of Outstanding Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)		Aggregate Intrinsic Value
Balance at December 31, 2021		3,425,285		$	6.17		7.82	$	6
Granted		1,263,317		$	0.47
Exercised		—		$	—
Cancelled		(369,324	)	$	3.85
Balance at March 31, 2022		4,319,278		$	4.70		7.60	$	181
Vested and expected to vest at March 31, 2022		4,319,278		$	4.70		7.60	$	181
Exercisable at March 31, 2022		1,340,204		$	5.97		5.78	$	4

Summary of Fair Value of Stock Option Grants

The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:

	Three Months Ended March 31,
	2022			2021
Risk-free interest rate	1.9%			0.6% – 1.0%
Expected volatility	87.5%			88.7% – 89.5%
Expected term (in years)	5.6			5.8 – 6.1
Expected dividend yield		0	%		0	%

Summary of Restricted Stock Units Activity

A summary of the Company’s restricted stock units activity is as follows (in thousands, except share and per share amounts):

	Number of Outstanding Awards			Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
Balance at December 31, 2021		468,500		$	4.09	$	314
Granted		1,263,317		$	0.47
Released		(55,400	)	$	4.09
Cancelled		—		$	—
Balance at March 31, 2022		1,676,417		$	1.36	$	429
Vested and expected to vest at March 31, 2022		1,676,417		$	1.36	$	429

Summary of Stock-Based Compensation Expense Recognized

Stock-based compensation expense recognized for all equity awards has been reported in the unaudited condensed consolidated statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
General and administrative	$	1,889	$	1,026
Research and development		121		494
Total stock-based compensation	$	2,010	$	1,520

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following:

	March 31,		December 31,
	2022		2021
Common stock options outstanding		4,319,278		3,425,285
Shares available for issuance under equity incentive plans		2,189,082		2,661,970
Restricted stock units outstanding		1,676,417		468,500
Shares available for issuance under the ESPP		1,004,710		583,605
Common stock warrant		154,240		154,240
Total common stock reserved for future issuance		9,343,727		7,293,600