Note 2 - Stock-Based Compensation (Detail) (USD $)	0 Months Ended	1 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		1 Months Ended						3 Months Ended
	Feb. 14, 2012	Feb. 28, 2011	Feb. 25, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2012 Restricted Stock [Member]	Apr. 24, 2012 Time Base Restricted Unit [Member]	Feb. 28, 2011 Time Base Restricted Unit [Member]	Feb. 28, 2011 CEO [Member]	Feb. 28, 2011 Executive Restricted Stock Unit [Member]	Apr. 24, 2012 Nonexecutive Restrcted Stock Unit [Member]	Apr. 24, 2012 Performance Based Restricted Stock Unit [Member]	Sep. 30, 2012 Employee Stock Purchase Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Description				one-for-one		The Company's Board of Directors adopted the Company's 2004 Equity Incentive Plan in March 2004, and the Company's stockholders approved it in November 2004. Options granted under the 2004 Plan have a maximum term of ten years. New hire grants generally vest over four years at the rate of 25percent one year from the date of grant and 1/48 th monthly thereafter. Refresh grants generally vest over four years at the rate of 50 percent two years from the date of grant and 1/48 th monthly thereafter. There were 800,000 shares initially reserved for issuance under the 2004 Plan. The 2004 Plan provides for annual increases in the number of shares available for issuance beginning on January1, 2005 equal to the lesser of: 5% of the outstanding shares of common stock on the first day of the year, 2,400,000 shares, or a number of shares determined by the Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value				$ 600,000	$ 1,200,000	$ 2,300,000	$ 4,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value				3,600,000	200,000	9,100,000	5,700,000
Proceeds from Stock Options Exercised				4,900,000	100,000	12,200,000	4,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options				1,900,000		1,900,000
Share Based Compensation Weighted Average Period Recognized								1 year 328 days	2 years 146 days							146 days
Share Based Compensation Arrangement By Share Based Payment Award Restricted Units Vested In Period Fair Value				3,400,000	2,100,000	8,500,000	5,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Intrinsic Value (in Dollars per share)				$ 3,300,000	$ 1,600,000	$ 7,700,000	$ 4,700,000
Share Based Compensation Arrangement By Share Based Payment Award Restricted Units Outstanding Intrinsic Value				33,700,000	13,400,000	33,700,000	13,400,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options					200,000		200,000		21,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	413,000		416,000							219,317	153,000			344,650	125,333
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		2 years													2 years
Share Based Compensation Share Based Payment Other Than Options Percentage Allowed												100.00%	300.00%
Performance Level RSU Reduction Percentage		15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee (in Shares)						2,000
Share Based Compensation Arrangement By Share Based Payment Award Maximum Amount Per Employee						$25,000
Employee Stock Ownership Plan (ESOP), Shares in ESOP (in Shares)				200,000		200,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)				54,523	79,296	151,770	149,981
Stock Issued During Period, Value, Employee Stock Purchase Plan				300,000	100,000	1,000,000	300,000
Proceeds from Stock Plans				$ 800,000		$ 1,852,000	$ 1,773,000