Note 11 - Business Segment and Geographic Financial Data - Geographic Segment Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Revenues	$ 5,535	$ 5,033
Assets	49,621		$ 49,974
UNITED STATES
Revenues	3,688	4,463
Assets	46,142		46,271
Non-US [Member]
Revenues	1,847	$ 570
Assets	$ 3,479		$ 3,703