Note 5 - Net Income per Share (Details) - Net Income Per Share Basic And Diluted (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Income Per Share Basic And Diluted [Abstract]
Net income (in Dollars)	$ 5,489	$ 6,592	$ 7,989	$ 9,587
Weighted average outstanding shares used to compute basic net income per share	37,053	34,665	36,657	34,385
Effect of dilutive securities	1,186	1,332	1,362	1,275
Weighted average outstanding shares used to compute diluted net income per share	38,239	35,997	38,019	35,660
Net income per share - basic (in Dollars per share)	$ 0.15	$ 0.19	$ 0.22	$ 0.28
Net income per share - diluted (in Dollars per share)	$ 0.14	$ 0.18	$ 0.21	$ 0.27