Note 4 - Stockholders' Equity (Details) (USD $)	3 Months Ended		9 Months Ended					9 Months Ended			12 Months Ended		9 Months Ended		34 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	May 27, 2014	Dec. 31, 2013	Nov. 08, 2012	Sep. 30, 2014 Employee Stock Option [Member]	Sep. 30, 2014 Restricted Stock [Member]	Oct. 21, 2014 Subsequent Event [Member]	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	May 27, 2014 Shares Previously Issued Under the 2001 Plan [Member]	Sep. 30, 2014 2011 Stock Incentive Plan [Member]	Sep. 30, 2014 IDS Plan [Member]	Sep. 30, 2014 2001 Stock Incentive Plan [Member]	Sep. 30, 2014 Outside of the 2011, 2001, or IDS Plans [Member]	Sep. 30, 2014 Employee Stock Purchase Plan [Member]	Sep. 30, 2014 Employee Stock Purchase Plan [Member]	Sep. 30, 2013 Employee Stock Purchase Plan [Member]
Note 4 - Stockholders' Equity (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years										4 years	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized					6,550,000							3,500,000
Share Based Compensation Arrangement By Share Based Payment Award Shares Reserved Decrease Rate			1.33
Share Based Compensation Arrangement By Share Based Payment Award Expiration Term													10 years	10 years
Common Stock, Capital Shares Reserved for Future Issuance													7,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant													3,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period			33,000												400,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,376,000		2,376,000			2,880,000										0
Share Price (in Dollars per share)	$ 12.61		$ 12.61
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value (in Dollars)								$ 6,500,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars)								2,500,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition								1 year 6 months	2 years 292 days									1 year 36 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value (in Dollars)			1,600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options (in Dollars)									15,100,000								400,000	400,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate																	10.00%	10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent																		85.00%
ESPP Maximum Annual Share Replenishment																		675,000
ESPP Maximum Annual Share Replenishment Percentage Of Prior Year Outstanding Company Common Stock																		2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans	62,000	80,000	114,000	184,000
Employee Stock Purchase Plan Weighted Average Purchase Price Of Shares Purchased (in Dollars per share)	$ 13.06	$ 9.66	$ 12.62	$ 7.16
Share-based Compensation (in Dollars)			6,259,000	4,942,000							100,000						100,000	500,000	500,000
Number Of ESPP Shares Available For Future Issuance								1,200,000
Stock Repurchase Program, Authorized Amount (in Dollars)							20,000,000			25,000,000
Stock Repurchased During Period, Shares			230,311
Stock Repurchsed During Period Average Per Share Price (in Dollars per share)			$ 17.56
Stock Repurchased During Period, Value (in Dollars)			4,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount (in Dollars)	$ 16,000,000		$ 16,000,000