Note 1 - General and Basis of Presentation - Changes in the Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Beginning balance of the allowance for expected credit losses	$ 90
Ending balance of the allowance for expected credit losses	90
Accounting Standards Update 2016-13 [Member]
Beginning balance of the allowance for expected credit losses	90	$ 597
Change in the provision for expected credit losses for the period	0	0
Ending balance of the allowance for expected credit losses	$ 90	$ 597