Note 11 - Business Segment and Geographic Financial Data - Geographic Segment Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Revenues	$ 6,368	$ 5,218	$ 11,903	$ 10,251
Assets	49,118		49,118		$ 49,974
UNITED STATES
Revenues	4,279	4,588	7,967	9,051
Assets	45,934		45,934		46,271
Non-US [Member]
Revenues	2,089	$ 630	3,936	$ 1,200
Assets	$ 3,184		$ 3,184		$ 3,703