Note 5 - Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance	$ 1,109	$ 1,101	$ 602	$ 554
Unbilled	305	284	1,950	1,813
Billings	(548)	(532)	(1,686)	(1,514)
Balance	866	853	866	853
Balance			3,200
Billings	548	532	1,686	1,514
Balance	4,000		4,000
Deferred Membership Dues [Member]
Billings	(787)	(831)	(5,428)	(5,175)
Balance	4,776	4,497	3,153	2,899
Billings	787	831	5,428	5,175
Revenue recognized	(1,522)	(1,474)	(4,540)	(4,220)
Balance	4,041	3,854	4,041	3,854
Customer Advance Deposits [Member]
Billings	(261)	(438)	(656)	(1,100)
Balance	652	556	553	453
Billings	261	438	656	1,100
Revenue recognized	(301)	(487)	(597)	(1,046)
Balance	$ 612	$ 507	$ 612	$ 507