Note 11 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Outstanding, options (in shares)	6,003
Outstanding, options, weighted average exercise price (in dollars per share)	$ 0.56
Outstanding, options, contractual life (Year)	6 years 1 month 6 days	6 years 4 months 24 days
Outstanding, options, aggregate intrinsic value	$ 0	$ 0
Options forfeited/expired (in shares)	(31)
Options forfeited/expired, weighted average exercise price (in dollars per share)	$ 0.53
Outstanding at March 31, 2023 (in shares)	5,972	6,003
Outstanding at March 31, 2023 (in dollars per share)	$ 0.56	$ 0.56
Options vested and exercisable at March 31, 2023 (in shares)	5,955
Options vested and exercisable at March 31, 2023 (in dollars per share)	$ 0.56
Options vested and exercisable at March 31, 2023	$ 0