Note 5 - Balance Sheet Components - Intangible assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Intangible assets, gross	$ 20,380	$ 22,180
Less accumulated amortization	(5,019)	(5,087)
Intangible assets, net	15,361	17,093
Purchased Technology [Member]
Intangible assets, gross	20,300	22,100
Intellectual Property [Member]
Intangible assets, gross	$ 80	$ 80