Note 8 - Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Notes Tables

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
	(000’s)				(000’s)
Research and development	$	458	$	146	$	1,382	$	229
General and administrative		1,663		1,482		2,742		2,666
Total	$	2,121	$	1,628	$	4,124	$	2,895

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

			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		3,453	$	1.82		9.55		—
Exercised		—	$	—		—		—
Forfeited/canceled		—	$	—		—		—
Outstanding at June 30, 2024		11,329	$	3.21		8.16	$	—
Vested at June 30, 2024		5,114	$	3.95		7.27	$	—

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Six Months Ended June 30,
	2024			2023
Expected term (in years)		6.0			6.0
Risk-free rate		4.04	%		3.80	%
Expected volatility		80	%		88	%
Expected dividend yield		—			—

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Shares (000's)			Weighted Average Price Per Share		Weighted Average Fair Value ($000's)
Unvested, December 31, 2023		1,500		$	3.89	$	5,835
Granted		2,391			1.93		4,615
Vested		(225	)		3.93		(884	)
Forfeited or canceled		—			—		—
Unvested, June 30, 2024		3,666		$	2.61	$	9,565