Note 16 - Quarterly Financial Data (Unaudited) (Detail) - Summary of Quarterly Financial Data (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
Revenue	$ 48,214	$ 56,508	$ 58,607	$ 50,484	$ 47,461	$ 52,962	$ 51,628	$ 44,468	$ 213,813		$ 196,519		$ 218,840
Cost of revenue (1)	22,661	26,495	27,435	24,074	22,544	25,148	25,070	22,163	100,665	[1]	94,925	[1]	97,383
Gross profit	25,553	30,013	31,172	26,410	24,917	27,814	26,558	22,305	113,148		101,594		121,457
Research and development (2)	13,243	11,967	12,468	11,118	11,403	11,792	11,237	10,086	48,796	[2]	44,518	[2]	44,372
Selling, general and administrative (3)	13,930	11,955	12,167	11,966	10,198	10,249	10,343	9,490	50,018	[3]	40,280	[3]	41,169
Litigation expense (benefit), net	(2,600)	(229)	(244)	128	905	722	939	813	(2,945)		3,379		5,418
Total operating expenses	24,573	23,693	24,391	23,212	22,506	22,763	22,519	20,389	95,869		88,177		90,959
Income from operations	980	6,320	6,781	3,198	2,411	5,051	4,039	1,916	17,279		13,417		30,498
Interest income (expense) and other, net	(10)	156	359	106	99	3	24	183	611		309		922
Income before income taxes	970	6,476	7,140	3,304	2,510	5,054	4,063	2,099	17,890		13,726		31,420
Income tax provision	722	555	548	309	57	(419)	581	206	2,134		425		1,857
Net income	248	5,921	6,592	2,995	2,453	5,473	3,482	1,893	15,756		13,301		29,563
Basic net income per share (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
Diluted net income per share (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
Basic (in Shares)	35,556	35,145	34,665	34,105	33,759	33,594	33,846	35,024	34,871		34,050		35,830
Diluted (in Shares)	36,763	36,438	35,997	35,538	34,374	34,240	34,903	36,105	36,247		35,160		37,826
Allocated Share Based Compensation Expense	7,326	4,182	3,829	3,315	3,090	3,374	3,675	2,987	18,652		13,136		16,810
Cost Of Revenue [Member]
Allocated Share Based Compensation Expense	185	112	118	95	77	83	89	63
Research and Development Expense [Member]
Allocated Share Based Compensation Expense	2,667	1,465	1,524	1,266	1,356	1,576	1,550	1,427
Selling, General and Administrative Expenses [Member]
Allocated Share Based Compensation Expense	$ 4,474	$ 2,605	$ 2,187	$ 1,954	$ 1,657	$ 1,715	$ 2,036	$ 1,497

[1] (1) Includes stock-based compensation expense

[2] (2) Includes stock-based compensation expense

[3] (3) Includes stock-based compensation expense