Note 4 - Balance Sheet Components - Right-of-Use Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Right-of-use assets, net	$ 2,591	$ 1,990
Facilities [Member]
Right-of-use assets, net	2,588	1,985
Office Equipment [Member]
Right-of-use assets, net	$ 3	$ 5