Stock-Based Compensation

3 Months Ended

Mar. 31, 2023

Text Block [Abstract]

Stock-Based Compensation

10.Stock-Based Compensation

The Company recognized stock-based compensation expense on all employee and non-employee awards as follows:

	For the Three Months Ended March 31,
(in thousands)	2023		2022
Research and development		176		315
General and administrative		735		538
Stock-based compensation expense	$	910	$	853

The Company granted an aggregate of 3,065,168 stock options during the three months ended March 31, 2023, with a weighted-average grant date fair value of $0.39 per share, and granted an aggregate of 2,690,000 stock options during the three months ended March 31, 2022, with a weighted-average grant date fair value of $0.47 per share.

For the three months ended March 31, 2023 and 2022, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:

	For the Three Months Ended March 31,
	2023	2022
Risk-free interest rate	3.58 – 3.87%	1.63 – 2.43%
Expected life in years	5.06 - 6.25	6.25
Expected volatility	89.69 - 95.63%	74.49 – 76.27%
Expected dividend yield	—%	—%

2.

Stock option activity under the Company’s stock option plans for the three months ended March 31, 2023 is as follows:

(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding, December 31, 2022		10,408,622		$	1.84
Granted		3,065,168			0.52
Cancelled		(160,544	)		1.90
Outstanding, March 31, 2023		13,313,246		$	1.54		8.80	$	364
Options exercisable, March 31, 2023		4,553,574		$	2.31		7.99	$	—
Options exercisable, December 31, 2022		3,891,598		$	2.46		8.08	$	—
Options available for future grant, March 31, 2023		12,555,464

At March 31, 2023, total unrecognized compensation costs related to unvested stock options outstanding amounted to $6.6 million. The cost is expected to be recognized over a weighted-average period of 1.96 years.

A summary of the status of unvested restricted stock for the three months ended March 31, 2023 is as follows:

	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested, December 31, 2022		939,062		$	1.40
Vested		(40,937	)		0.90
Unvested, March 31, 2023		898,125		$	1.43

At March 31, 2023, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $0.9 million. The cost is expected to be recognized over a weighted-average period of 1.72 years.