Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 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 as of December 31, 2021		2,132		$	3
Vested shares		(2,132	)		(3	)
Balance as of June 30, 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 as of December 31, 2021		3,425,285		$	6.17		7.82	$	6
Granted		1,378,817		$	0.47
Exercised		—		$	—
Cancelled		(601,471	)	$	4.93
Balance as of June 30, 2022		4,202,631		$	4.47		7.69	$	48
Vested and expected to vest as of June 30, 2022		4,202,631		$	4.47		7.69	$	48
Exercisable as of June 30, 2022		1,537,939		$	6.04		6.05	$	1

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:

	Six Months Ended June 30,
	2022			2021
Risk-free interest rate	1.9% – 2.9%			0.6% – 1.1%
Expected volatility	81.8% – 87.5%			87.9% – 89.5%
Expected term (in years)	5.5 – 5.6			5.5 – 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 as of December 31, 2021		468,500		$	4.09	$	314
Granted		1,263,317		$	0.47
Released		(453,500	)	$	4.09
Cancelled		(15,000	)	$	4.09
Balance as of June 30, 2022		1,263,317		$	0.47	$	38
Vested and expected to vest as of June 30, 2022		1,263,317		$	0.47	$	38

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 June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
General and administrative	$	1,098	$	1,310	$	2,987	$	2,336
Research and development		174		276		295		770
Total stock-based compensation	$	1,272	$	1,586	$	3,282	$	3,106

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following:

	June 30,		December 31,
	2022		2021
Common stock options outstanding		4,202,631		3,425,285
Shares available for issuance under equity incentive plans		2,305,729		2,661,970
Restricted stock units outstanding		1,263,317		468,500
Shares available for issuance under the ESPP		999,255		583,605
Common stock warrant		154,240		154,240
Total common stock reserved for future issuance		8,925,172		7,293,600