Note 2 - Stock-Based Compensation (Detail) (USD $)	1 Months Ended			3 Months Ended		6 Months Ended			1 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 28, 2010	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Restricted Stock [Member]	Apr. 30, 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. 30, 2012 Nonexecutive Restrcted Stock Unit [Member]	Apr. 30, 2012 Performance Based Restricted Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Description						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 thelesser 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				$ 800,000	$ 1,500,000	$ 1,700,000	$ 3,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value				2,800,000	700,000	5,500,000	5,500,000
Proceeds from Stock Options Exercised				3,400,000	700,000	7,300,000	4,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options				2,600,000		2,600,000
Share Based Compensation Arrangement By Share Based Payment Award Restricted Units Vested In Period Fair Value				2,900,000	2,100,000	5,100,000	4,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value (in Dollars per share)				$ 2,400,000	$ 1,400,000	$ 4,400,000	$ 3,100,000
Share Based Compensation Arrangement By Share Based Payment Award Restricted Units Outstanding Intrinsic Value				36,600,000	21,800,000	36,600,000	21,800,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options					100,000		100,000	22,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	413,000		416,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in Shares)									219,317	153,000			344,650	125,333
Share Based Compensation Share Based Payment Other Than Options Percentage Allowed		100.00%									100.00%	300.00%
Performance Level RSU Reduction Percentage		15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period														2 years
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)							70,685
Stock Issued During Period, Value, Employee Stock Purchase Plan						700,000	200,000
Proceeds from Stock Plans						$ 1,036,000	$ 928,000