Note 13 - Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2025

Notes Tables

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

						Weighted
						average
				Weighted		remaining		Aggregate
				average		contractual		intrinsic
	Number of			exercise		life (in		value (in
	shares			price		years)		thousands)
Outstanding as of December 31, 2023		264,983		$	18.30		7.7	$	75
Options granted		—			—		—		—
Forfeited/Expire		(143,150	)		—		—		—
Outstanding as of December 31, 2024		121,833			22.36		7.0		—
Options granted		547,000			1.84		10.0
Forfeited/Expire		(5,380	)		—		—		—
Outstanding as of September 30, 2025		663,453			5.54		9.0		—
Options vested and exercisable as of September 30, 2025		119,281		$	22.52		6.3	$	—

Nonvested Restricted Stock Shares Activity [Table Text Block]

				Weighted
				Average Grant
				Date Fair
	Awards			Value
Balance as of December 31, 2023 (unvested)		124,166		$	5.20
Granted		—
Vested		(90,833	)	$	4.64
Forfeited		(33,333	)	$	5.20
Balance as of December 31, 2024 (unvested)		—			—
Granted		—		$	—
Vested		—		$	—
Forfeited		—		$	—
Balance as of September 30, 2025 (unvested)		—			—

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

	Three months ended September 30,				Nine months ended September 30,
	2025		2024		2025		2024
	(Unaudited)
Stock-based compensation expense
General and administrative	$	56	$	82	$	123	$	365
Research and development		12		22		24		78
Total stock-based compensation expense	$	68	$	97	$	147	$	339