Note 3 - Revenue - Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues	$ 5,218	$ 4,401	$ 10,251	$ 8,179
Transferred at Point in Time [Member]
Revenues	4,995	2,932	9,655	5,981
Transferred over Time [Member]
Revenues	$ 223	$ 1,469	$ 596	$ 2,198