Note 9 - Revenue (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer, Excluding Assessed Tax	$ 700	$ 1,418	$ 0
Redemption of Non Cash Credits [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 400	$ 1,100