Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

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Stock-Based Compensation Expense on All Employee and Non-Employee Awards

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

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Research and development	$	2	$	180	$	13	$	356
General and administrative		99		734		260		1,468
Stock-based compensation expense	$	101	$	914	$	273	$	1,824

Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model

For the three and six months ended June 30, 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:

	For the Six Months Ended June 30,
	2024	2023
Risk-free interest rate	4.09%	3.51 – 3.87%
Expected life in years	5.04-5.27	5.06 – 6.25
Expected volatility	114.65 -170.50%	89.69 – 95.63%
Expected dividend yield	—%	—%

Stock Option Activity under Stock Option Plan

Stock option activity under the Company’s stock option plans for the six months ended June 30, 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		46,589		$	268.50	7.64		$	—
Granted		10,289			13.29
Exercised		-			-
Cancelled		(26,641	)		283.08
Outstanding, June 30, 2024		30,237		$	168.81		7.46	$	—
Options exercisable, June 30, 2024		17,743		$	250.45		6.10	$	—
Options available for future grant, June 30, 2024		145,745