Note 8 - Stock-based Compensation

3 Months Ended

Mar. 31, 2024

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, 2024 and 2023 was classified in the condensed consolidated statement of operations as follows (in thousands):

		Three Months Ended March 31,
		2024				2023
		(000’s)
Research and development		$	924			$	83
General and administrative			1,079				1,184
Total		$	2,003			$	1,267

As of March 31, 2024, the remaining unrecognized stock-based compensation cost from all plans to be recognized in future periods totaled $21.5 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, 2024 was 5.1 million shares. As of March 31, 2024, 4.5 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, 2023			7,876			$	3.81				8.05			$	11
Granted			3,440			$	1.83				9.80				—
Exercised			—			$	—				—				—
Forfeited/canceled			—			$	—				—				—
Outstanding at March 31, 2024			11,316			$	3.21				8.41			$	627
Vested at March 31, 2024			4,447			$	4.10				7.33			$	60

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. As of March 31, 2024, the total unrecognized compensation cost related to outstanding options was $12.7 million, to be recognized over a weighted average period of 1.5 years.

For the three months ended March 31, 2023, the weighted average grant date fair value for options granted was $2.95. The intrinsic value for options vested as of March 31, 2023 was $0.5 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, 2024 and 2023 were as follows:

		Three Months Ended March 31,
		2024				2023
Expected term (in years)			6.0				6.0
Risk-free rate			4.04	%			3.80	%
Expected volatility			80	%			89	%
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, 2023			1,500			$	3.83			$	5,745
Granted			2,391				1.93				4,622
Vested			(225	)			3.93				(884	)
Forfeited or canceled			—				—				—
Unvested, March 31, 2024			3,666			$	2.61			$	9,483

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, 2024, the remaining unrecognized compensation cost related to RSUs to be recognized in future periods totaled $8.7 million, which is expected to be recognized over a weighted average period of 2.0 years.