Note 2 - Revenue Recognition - Significant Changes in Contract Assets and Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Balance at beginning of period	$ 51	$ 46
Revenue recognized	0	50
Amounts collected or invoiced	0	(45)
Balance at end of period	51	51
Balance at beginning of period	577	1,138
Revenue recognized	(253)	(1,173)
Amounts collected or invoiced	65	424
Balance at end of period	$ 389	$ 389