Note 16 - Quarterly Financial Data (Unaudited) (Details) - Summary of Quarterly Financial Data (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended			3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Note 16 - Quarterly Financial Data (Unaudited) (Details) - Summary of Quarterly Financial Data [Line Items]
Revenue	$ 238,091	$ 213,813	$ 196,519	$ 63,560	$ 65,347	$ 57,714	$ 51,470	$ 48,214	$ 56,508	$ 58,607	$ 50,484
Cost of revenue	110,190	100,665	94,925	29,266	30,053	26,786	24,085	22,661	26,495	27,435	24,074
Gross profit	127,901	113,148	101,594	34,294	35,294	30,928	27,385	25,553	30,013	31,172	26,410
Operating expenses:
Research and development	49,733	48,796	44,518	12,487	12,643	12,478	12,123	13,243	11,967	12,468	11,118
Selling, general and administrative	54,624	50,018	40,280	13,683	13,891	13,793	13,258	13,930	11,955	12,167	11,966
Litigation expense (benefit), net	(371)	(2,945)	3,379	84	104	(257)	(301)	(2,600)	(229)	(244)	128
Total operating expenses	103,986	95,869	88,177	26,254	26,638	26,014	25,080	24,573	23,693	24,391	23,212
Income from operations	23,915	17,279	13,417	8,040	8,656	4,914	2,305	980	6,320	6,781	3,198
Interest and other income (expense), net	92	611	309	(57)	(59)	218	(10)	(10)	156	359	106
Income before income taxes	24,007	17,890	13,726	7,983	8,597	5,132	2,295	970	6,476	7,140	3,304
Income tax provision (benefit)	1,109	2,134	425	484	1,187	(357)	(204)	722	555	548	309
Net income	$ 22,898	$ 15,756	$ 13,301	$ 7,499	$ 7,410	$ 5,489	$ 2,499	$ 248	$ 5,921	$ 6,592	$ 2,995
Basic net income per share (in Dollars per share)	$ 0.61	$ 0.45	$ 0.39	$ 0.20	$ 0.20	$ 0.15	$ 0.07	$ 0.01	$ 0.17	$ 0.19	$ 0.09
Diluted net income per share (in Dollars per share)	$ 0.59	$ 0.43	$ 0.38	$ 0.19	$ 0.19	$ 0.14	$ 0.07	$ 0.01	$ 0.16	$ 0.18	$ 0.08
Weighted-average common shares outstanding:
Basic (in Shares)				38,328	37,910	37,053	36,259	35,556	35,145	34,665	34,105
Diluted (in Shares)	38,620	36,247	35,160	39,524	39,009	38,239	37,708	36,763	36,438	35,997	35,538