Note 7 - Net Income per Share (Detail) - Net Income Per Share Basic And Diluted (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income (in Dollars)	$ 248	$ 5,921	$ 6,592	$ 2,995	$ 2,453	$ 5,473	$ 3,482	$ 1,893	$ 15,756	$ 13,301	$ 29,563
Weighted average outstanding shares used to compute basic net income per share	35,556	35,145	34,665	34,105	33,759	33,594	33,846	35,024	34,871	34,050	35,830
Effect of dilutive securities									1,376	1,110	1,996
Weighted average outstanding shares used to compute diluted net income per share	36,763	36,438	35,997	35,538	34,374	34,240	34,903	36,105	36,247	35,160	37,826
Net income per share - basic (in Dollars per share)	$ 0.01	$ 0.17	$ 0.19	$ 0.09	$ 0.07	$ 0.16	$ 0.10	$ 0.05	$ 0.45	$ 0.39	$ 0.83
Net income per share - diluted (in Dollars per share)	$ 0.01	$ 0.16	$ 0.18	$ 0.08	$ 0.07	$ 0.16	$ 0.10	$ 0.05	$ 0.43	$ 0.38	$ 0.78