Note 10 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Oct. 31, 2018
Options outstanding, number of options (in shares)	1,274,182
Options outstanding, weighted average exercise price (in dollars per share)	$ 9.17
Options outstanding, weighted average remaining contract term (Year)	3 years 6 months	4 years 6 months
Options outstanding, aggregate intrinsic value	$ 193	$ 412
Granted, number of options (in shares)	0
Granted, weighted average exercise price (in dollars per share)	$ 0
Granted aggregate intrinsic value
Exercised, number of options (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Canceled or forfeited, number of options (in shares)	(30,109)
Canceled or forfeited, weighted average exercise price (in dollars per share)	$ 10.28
Options outstanding, number of options (in shares)	1,244,073	1,274,182
Options outstanding, weighted average exercise price (in dollars per share)	$ 9.14	$ 9.17
Exercisable, number of options (in shares)	1,223,919		543,618
Exercisable, weighted average exercise price (in dollars per share)	$ 8.98
Exercisable, weighted average remaining contract term (Year)	3 years 4 months 24 days
Exercisable, aggregate intrinsic value	$ 193