Note 1 - Business and Significant Accounting Policies - Changes in the Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Beginning balance of the allowance for expected credit losses	$ 597
Ending balance of the allowance for expected credit losses	90	$ 597
Accounting Standards Update 2016-13 [Member]
Beginning balance of the allowance for expected credit losses	597	755
Change in the provision for expected credit losses for the period	(507)	(158)
Ending balance of the allowance for expected credit losses	$ 90	$ 597