Note 11 - Business Segment and Geographic Financial Data - Geographic Segment Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Revenues	$ 7,988	$ 8,017	$ 20,736	$ 19,920
Assets	50,319		50,319		$ 50,124
UNITED STATES
Revenues	5,640	6,972	15,937	14,939
Assets	46,550		46,550		47,007
Non-US [Member]
Revenues	2,348	$ 1,045	4,799	$ 4,981
Assets	$ 3,769		$ 3,769		$ 3,117