Note 8 - Stock-based Compensation

6 Months Ended

Jun. 30, 2025

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

8.	Stock-Based Compensation

Stock-based compensation expense for the three and six months ended June 30, 2025 and 2024 was classified in the condensed consolidated statement of operations as follows (in thousands):

		Three Months Ended June 30,								Six Months Ended June 30,
		2025				2024				2025				2024
		(000’s)								(000’s)
Research and development		$	857			$	458			$	1,664			$	1,382
General and administrative			1,934				1,663				3,641				2,742
Total		$	2,791			$	2,121			$	5,305			$	4,124

As of June 30, 2025, the remaining unrecognized stock-based compensation cost from all plans to be recognized in future periods totaled $24.8 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 June 30, 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				9.61				2
Exercised			—			$	—				—				—
Forfeited/canceled			—			$	—				—				—
Outstanding at June 30, 2025			18,544			$	3.02				6.67			$	7,064
Vested at June 30, 2025			8,336			$	3.46				5.22			$	2,125

For the six months ended June 30, 2025, the weighted average grant date fair value for options granted was $2.68. The intrinsic value for options vested as of June 30, 2025, was $2.1 million. As of June 30, 2025, the total unrecognized compensation cost related to outstanding options was $19.5 million, to be recognized over a weighted average period of 1.5 years.

For the six months ended June 30, 2024, the weighted average grant date fair value for options granted was $1.82. The options had no intrinsic value as of June 30, 2024. As of June 30, 2024, the total unrecognized compensation cost related to outstanding options was $11.4 million, to be recognized over a weighted average period of 1.5 years.

The weighted average assumptions used in the Black-Scholes pricing model to determine the fair value of stock options granted during the six months ended June 30, 2025 and 2024 were as follows:

		Six Months Ended June 30,
		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, June 30, 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 June 30, 2025, the remaining unrecognized compensation cost related to RSUs to be recognized in future periods totaled $5.3 million, which is expected to be recognized over a weighted average period of 1.4 years.