Note 8 - Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

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

	Three months ended
	March 31,
	2023		2022
Research and development	$	139	$	127
Selling, general and administrative		139		192
Total share-based compensation	$	278	$	319

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 exercised		(199	)		1.49
Stock options forfeited		(14,059	)		2.77
Balance, March 31, 2023		2,168,450		$	4.05		7.3	$	256
Exercisable, March 31, 2023		1,241,371		$	5.27		6.3	$	49

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 released		(18,792	)		4.34
Balance, March 31, 2023		2,734		$	4.26