Note 3 - Revenue - Revenues Disaggregated by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues	$ 7,559	$ 8,155	$ 17,810	$ 16,334
UNITED STATES
Revenues	6,049	6,473	15,100	12,880
Latin America [Member]
Revenues	121	195	338	400
Europe [Member]
Revenues	663	904	1,339	1,494
Asia [Member]
Revenues	726	583	1,033	1,560
Non-US [Member]
Revenues	$ 1,510	$ 1,682	$ 2,710	$ 3,454