Note 3 - Revenue - Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues from external customers	$ 8,155	$ 6,452	$ 16,334	$ 25,555
Transferred at Point in Time [Member]
Revenues from external customers	5,108	5,261	11,089	15,828
Transferred over Time [Member]
Revenues from external customers	$ 3,047	$ 1,191	$ 5,245	$ 9,727