Note 8 - Stock-based Compensation

3 Months Ended

Mar. 31, 2025

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

8. Stock-Based Compensation

Stock-based compensation expense for the three months ended March 31, 2025 and 2024 was classified in the condensed consolidated statement of operations as follows (in thousands):

	Three Months Ended March 31,
	2025		2024
	(000’s)
Research and development	$	807	$	924
General and administrative		1,707		1,079
Total	$	2,514	$	2,003

As of March 31, 2025, the remaining unrecognized stock-based compensation cost from all plans to be recognized in future periods totaled $27.6 million.

2020 Plan

In June 2020, the Company’s board of directors adopted the 2020 Stock Option and Incentive Plan (the “2020 Plan”) and reserved 2.9 million shares of common stock for issuance under this plan. The 2020 Plan includes automatic annual increases. The increase on January 1, 2025 was 5.5 million shares. As of March 31, 2025, 1.9 million shares remain available for grant.

The 2020 Plan authorizes the board of directors or a committee of the board to grant incentive stock options, nonqualified stock options, restricted stock awards and restricted stock units ("RSUs") to eligible officers, employees, consultants and directors of the Company. Options generally vest over a period of four years and have a contractual life of ten years from the date of grant.

Stock Options:

The following table summarizes the stock option activity for the 2020 Plan:

			Weighted		Weighted
	Number of		Average		Average		Aggregate
	Unvested		Exercise		Remaining		Intrinsic
	Options		Price		Contractual		Value
	(000's)		Per Share		Term (in years)		($000's)
Outstanding at December 31, 2024		14,062	$	2.83		6.23	$	579
Granted		4,482	$	3.61		9.86		2
Exercised		—	$	—		—		—
Forfeited/canceled		—	$	—		—		—
Outstanding at March 31, 2025		18,544	$	3.02		6.92	$	2,146
Vested at March 31, 2025		7,379	$	3.55		5.22	$	374

For the three months ended March 31, 2025, the weighted average grant date fair value for options granted was $2.68. The intrinsic value for options vested as of March 31, 2025, was $0.4 million. As of March 31, 2025, the total unrecognized compensation cost related to outstanding options was $21.5 million, to be recognized over a weighted average period of 1.6 years.

For the three months ended March 31, 2024, the weighted average grant date fair value for options granted was $1.30. The intrinsic value for options vested as of March 31, 2024 was $0.6 million.

The weighted average assumptions used in the Black-Scholes pricing model to determine the fair value of stock options granted during the three months ended March 31, 2025 and 2024 were as follows:

	Three Months Ended March 31,
	2025			2024
Expected term (in years)		6.0			6.0
Risk-free rate		4.28	%		4.04	%
Expected volatility		86	%		80	%
Expected dividend yield		—			—

RSUs:

The following table summarizes the RSU activity for the 2020 Plan:

	Shares (000's)			Weighted Average Price Per Share		Weighted Average Fair Value ($000's)
Unvested, December 31, 2024		3,766		$	2.41	$	9,076
Granted		—			—		—
Vested		(823	)		2.48		(2,042	)
Forfeited or canceled		—			—		—
Unvested, March 31, 2025		2,943		$	2.39	$	7,034

The weighted average price per share is the weighted grant price based on the closing market price of each of the stock grants. The weighted average fair value is the weighted average share price times the number of shares.

As of March 31, 2025, the remaining unrecognized compensation cost related to RSUs to be recognized in future periods totaled $6.2 million, which is expected to be recognized over a weighted average period of 1.7 years.