Note 5 - Net Income per Share (Details) - Net Income Per Share Basic And Diluted (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Income Per Share Basic And Diluted [Abstract]
Net income (in Dollars)	$ 7,410	$ 5,921	$ 15,399	$ 15,508
Weighted average outstanding shares used to compute basic net income per share	37,910	35,145	37,079	34,677
Effect of dilutive securities	1,099	1,293	1,340	1,331
Weighted average outstanding shares used to compute diluted net income per share	39,009	36,438	38,419	36,008
Net income per share - basic (in Dollars per share)	$ 0.20	$ 0.17	$ 0.42	$ 0.45
Net income per share - diluted (in Dollars per share)	$ 0.19	$ 0.16	$ 0.40	$ 0.43