Note 3 - Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net loss	$ (8,636)	$ (9,435)
Net loss — the Company	$ (8,619)	$ (9,259)
Weighted-average shares of common stock outstanding used in computing net loss per share, basic and diluted (in shares)	63,988	53,744
Basic (in dollars per share)	$ (0.13)	$ (0.17)