Stock-Based Compensation

3 Months Ended

Mar. 31, 2024

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


	Three Months Ended March 31,
(in thousands)	2024		2023
Research and development	$	11	$	175
General and administrative		161		735
Stock-based compensation expense	$	172	$	910

The Company granted an aggregate of 40,000 stock options during the three months ended March 31, 2024, with a weighted-average grant date fair value of $1.50 per share, and granted an aggregate of 204,344 stock options during the three months ended March 31, 2023, with a weighted-average grant date fair value of $5.85 per share.

For the three months ended March 31, 2024 and 2023, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:


	Three Months Ended March 31,
	2024	2023
Risk-free interest rate	4.09%	3.58 – 3.87%
Expected life in years	5.27	5.06 – 6.25
Expected volatility	114.65%	89.69 – 95.63%
Expected dividend yield	—%	—%

Stock option activity under the Company’s stock option plans for the three months ended March 31, 2024 was 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, 2023		465,898		$	26.85
Granted		40,000			1.80
Exercised		-			-
Cancelled		(254,441	)		19.61
Outstanding, March 31, 2024		251,457		$	21.15		6.92	$	—
Options exercisable, March 31, 2024		161,844		$	28.28		5.53	$	—
Options available for future grant, March 31, 2024		1,514,087

At March 31, 2024, total unrecognized compensation costs related to unvested stock options outstanding amounted to $0.1 million. The cost is expected to be recognized over a weighted-average period of 1.28 years.