Note 11 - Business Segment and Geographic Financial Data - Geographic Segment Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Revenues	$ 7,851	$ 7,988	$ 19,850	$ 20,736
Assets	50,117		50,117		$ 50,388
UNITED STATES
Revenues	5,453	5,640	13,519	15,937
Assets	45,789		45,789		46,487
Non-US [Member]
Revenues	2,398	$ 2,348	6,331	$ 4,799
Assets	$ 4,328		$ 4,328		$ 3,901