Note 9 - Information About Geographic Areas and Operating Segments - Revenue and Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended			12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2020
Total revenue	$ 10,646	$ 10,420	$ 14,718	$ 31,289	$ 36,073	$ 43,994	$ 59,360
Total long-lived assets	1,956			1,956				$ 1,358
North America [Member]
Total revenue	9,258	8,919		26,067	30,449
Total long-lived assets	1,780			1,780				1,179
Europe [Member]
Total revenue	112	785		476	1,819
Total long-lived assets	176			176				$ 179
Asia [Member]
Total revenue	$ 1,276	$ 716		$ 4,746	$ 3,805