Note 9 - Net Loss Per Share - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net loss	$ (12,414)	$ (8,220)
Weighted average shares of common stock outstanding used in computing net loss per share, basic (in shares)	14,433	14,017
Dilutive effect of incremental shares and share equivalents (in shares)
Weighted average shares of common stock outstanding used in computing net loss per share, diluted (in shares)	14,433	14,017
Net loss per share, basic and diluted (in dollars per share)	$ (0.86)	$ (0.59)