Note 16 - Stock-based Compensation

9 Months Ended

Sep. 30, 2025

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

Note 16 – Stock-Based Compensation

We recognize expense in our interim unaudited condensed consolidated financial statements related to all stock-based awards granted to employees and non-employee directors based on their fair value on the grant date. Compensation expense related to stock options is calculated using the Black-Scholes option-pricing model and is recognized ratably over the vesting period. While individual grants may vary, option awards generally have a 10-year term, are exercisable upon vesting, and vest with respect to one-twelfth of the total number of shares subject to the options on a quarterly basis (every three months) or vest with respect to one-third of the total number of shares subject to the options on an annual basis (every twelve months). Compensation expense related to restricted stock unit, or RSU, awards is also recognized ratably over the vesting period. While individual awards may vary, RSUs generally vest with respect to one-third of the total number of shares subject to the RSUs on an annual basis (every twelve months).

A summary of activity under our long-term incentive plans is presented below:

(in whole numbers)
Stock Options	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (In Yrs)
Outstanding at January 1, 2025		290		$	77,533
Forfeited or expired		(123	)		70,174
Outstanding at September 30, 2025		168		$	82,920		4.9
Vested and exercisable at September 30, 2025		141		$	98,377		4.4
Vested and expected to vest at September 30, 2025		168		$	82,920		4.9

During the nine months ended September 30, 2025, there were no RSUs granted or forfeited. As of  September 30, 2025, there were 154 RSU shares outstanding with a weighted-average grant date fair value of $1,895.03. 

The table below summarizes the total stock-based compensation expense included in the interim unaudited condensed consolidated statements of operations for the periods presented:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2025		2024		2025		2024
Research and development	$	9	$	32	$	44	$	114
General and administrative		8		55		77		321
Total	$	17	$	86	$	121	$	434

The fair value of each option award is estimated on the grant date using the Black-Scholes option-pricing formula. Expected volatilities are based upon the historical volatility of our common stock and other factors. We also use historical data and other factors to estimate option exercises, employee terminations and forfeiture rates. The risk-free interest rates are based upon the U.S. Treasury yield curve in effect at the time of the grant. No options or RSUs were granted during the nine months ended September 30, 2025 and 2024.