Note 9 - Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

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

	Three months ended March 31,
	2020		2019
Cost of goods sold	$	—	$	46
Research and development		413		242
Selling, general and administrative		528		402
Total share-based compensation expense	$	941	$	690

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

	Options outstanding
	Number of shares			Weighted average exercise price		Weighted average remaining contractual term (years)
Balance, December 31, 2019		821,464		$	18.99		6.6
Stock options granted		31,455			5.33
Stock options exercised		—			—
Stock options canceled		(16,947	)		16.32
Balance, March 31, 2020		835,972		$	7.20		7.4
Exercisable and vested, March 31, 2020		472,113		$	8.63		6.4

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

	Number of shares			Weighted average grant date fair value per share
Balance, December 31, 2019		36,981		$	10.56
RSUs granted		—			—
RSUs vested		(23,172	)		10.56
RSUs forfeited		(13,809	)		—
Balance, March 31, 2020		—		$	—