Note 8 - Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2023

Notes Tables

Schedule of Share-based Compensation, Expense [Table Text Block]

	Three months ended				Six months ended
	June 30,				June 30,
	2023		2022		2023		2022
Research and development	$	134	$	130	$	273	$	257
Selling, general and administrative		183		174		322		366
Total share-based compensation	$	317	$	304	$	595	$	623

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

	Options outstanding
	Number of shares			Weighted average exercise price		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in thousands)
Balance, December 31, 2022		2,182,708		$	4.04		7.5	$	343
Stock options granted		543,513			1.69
Stock options exercised		(199	)		1.49
Stock options forfeited		(119,941	)		2.36
Balance, June 30, 2023		2,606,081		$	3.63		7.3	$	1,189
Exercisable, June 30, 2023		1,443,515		$	4.83		6.0	$	315

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

				Weighted
				average
				grant date
	Number of			fair value
	shares			per share
Balance, December 31, 2022		21,526		$	4.33
RSUs granted		331,552			1.70
RSUs released		(241,197	)		1.93
RSUs forfeited		(111,881	)		1.70
Balance, June 30, 2023		—		$	n/a