Note 6 - Net Income Per Share - Calculation of Earnings 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)	$ (2,096)	$ 189	$ (2,520)	$ 706
Basic weighted-average common shares outstanding (in shares)	31,962	32,111	32,065	32,051
Effect of dilutive options and restricted stock (in shares)		1,277		1,440
Diluted weighted average shares outstanding (in shares)	31,962	33,388	32,065	33,491
Net income (loss) per share - Basic (in dollars per share)	$ (0.07)	$ 0.01	$ (0.08)	$ 0.02
Net income (loss) per share - Diluted (in dollars per share)	$ (0.07)	$ 0.01	$ (0.08)	$ 0.02