Note 12 - Net Loss Per Share - Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net loss	$ (14,709)	$ (13,987)	$ (12,308)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	5,644,328	4,264,178	4,240,060
Net loss per share, basic and diluted (in dollars per share)	$ (2.61)	$ (3.28)	$ (2.90)