Note 11 - Business Segment and Geographic Financial Data - Geographic Segment Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Revenues	$ 5,461	$ 6,368	$ 12,748	$ 11,903
Assets	49,609		49,609		$ 50,124
UNITED STATES
Revenues	4,316	4,279	10,297	7,967
Assets	46,191		46,191		47,007
Non-US [Member]
Revenues	1,145	$ 2,089	2,451	$ 3,936
Assets	$ 3,418		$ 3,418		$ 3,117