Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

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, 2020		36,492		$	27
Repurchased shares		(2,695	)		(1	)
Vested shares		(31,665	)		(23	)
Balance at December 31, 2021		2,132		$	3

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, 2020		3,136,076		$	5.23		7.95	$	8,963
Granted		1,246,705		$	7.30
Exercised		(491,695	)	$	2.23
Cancelled		(465,801	)	$	7.06
Balance at December 31, 2021		3,425,285		$	6.17		7.82	$	6
Vested and expected to vest at December 31, 2021		3,425,285		$	6.17		7.80	$	6
Exercisable at December 31, 2021		1,356,322		$	4.86		6.17	$	6

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:

	Years Ended December 31,
	2021	2020
Risk-free interest rate	0.6% – 1.3%	0.4% – 0.7%
Expected volatility	84.2% – 89.5%	82.4% – 94.8%
Expected term (in years)	5.5 – 6.1	5.8 – 10.0
Expected dividend yield	0.0%		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, 2020		-		$	-
Granted		579,150		$	4.09
Cancelled		(110,650	)	$	4.09
Balance at December 31, 2021		468,500		$	4.09	$	314
Vested and expected to vest at December 31, 2021		468,500		$	4.09	$	314

Summary of Stock-Based Compensation Expense Recognized

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

	Years Ended December 31,
	2021		2020
General and administrative	$	5,308	$	3,788
Research and development		1,641		1,233
Total stock-based compensation	$	6,949	$	5,021

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following:

	Years Ended December 31,
	2021		2020
Common stock options outstanding		3,425,285		3,136,076
Shares available for issuance under equity incentive plans		2,661,970		2,907,742
Shares available for issuance under the ESPP		583,605		405,000
Restricted stock units outstanding		468,500		—
Common stock warrant		154,240		23,122
Total common stock reserved for future issuance		7,293,600		6,471,940