Note 6 - Net Income Per Share (Details) - Net Income Per Share Basic And Diluted - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income (in Dollars)	$ 7,899	$ 6,397	$ 13,862	$ 15,415
Denominator:
Weighted-average outstanding shares used to compute basic net income per share	39,570	38,684	39,337	38,577
Effect of dilutive securities	1,175	924	1,333	986
Weighted-average outstanding shares used to compute diluted net income per share	40,745	39,608	40,670	39,563
Net income per share:
Basic (in Dollars per share)	$ 0.20	$ 0.17	$ 0.35	$ 0.40
Diluted (in Dollars per share)	$ 0.19	$ 0.16	$ 0.34	$ 0.39