Note 9 - Information About Geographic Areas and Operating Segments - Revenue and Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2020
Total revenue	$ 10,671	$ 8,924	$ 14,718	$ 20,643	$ 25,653	$ 43,994	$ 59,360
Total long-lived assets	1,837			1,837				$ 1,358
North America [Member]
Total revenue	8,221	7,754		16,809	21,530
Total long-lived assets	1,666			1,666				1,179
Europe [Member]
Total revenue	138	395		359	1,034
Total long-lived assets	171			171				$ 179
Asia [Member]
Total revenue	$ 2,312	$ 775		$ 3,475	$ 3,089