Note 10 - Net Loss Per Share - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income (loss)	$ (1,572)	$ 1,947	$ (3,604)	$ 925
Weighted average shares of common stock outstanding used in computing net income (loss) per share, basic (in shares)	13,709	13,935	13,649	13,888
Dilutive effect of incremental shares and share equivalents (in shares)		694		745
Weighted average shares of common stock outstanding used in computing net income (loss) per share, diluted (in shares)	13,709	14,629	13,649	14,633
Net income (loss) per share, basic (in dollars per share)	$ (0.11)	$ 0.14	$ (0.26)	$ 0.07
Net income (loss) per share, diluted (in dollars per share)	$ (0.11)	$ 0.13	$ (0.26)	$ 0.06