Note 6 - Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Balance	$ 1,102	$ 1,109	$ 585	$ 602
Unbilled	237	305	1,802	1,950
Billings	(500)	(548)	(1,548)	(1,686)
Balance	839	866	839	866
Balance			3,200
Billings	500	548	1,548	1,686
Balance	4,400		4,400
Deferred Membership Dues [Member]
Billings	(730)	(787)	(6,178)	(5,428)
Balance	5,376	4,776	3,196	3,153
Billings	730	787	6,178	5,428
Revenue recognized	(1,684)	(1,522)	(4,952)	(4,540)
Balance	4,422	4,041	4,422	4,041
Customer Advance Deposits [Member]
Billings	(588)	(261)	(1,299)	(656)
Balance	784	652	674	553
Billings	588	261	1,299	656
Revenue recognized	(688)	(301)	(1,289)	(597)
Balance	$ 684	$ 612	$ 684	$ 612