Note 2 - Summary of Significant Accounting Policies (Details) - Stock Option Activity - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Option Activity [Abstract]
Outstanding Balance	4,965,947	7,334,745	9,463,657
Outstanding Balance	$ 12.96	$ 12.33	$ 11.76
Outstanding Balance	5 years 219 days
Exercisable at December 31, 2015	3,328,227
Exercisable at December 31, 2015	$ 10.89
Exercisable at December 31, 2015	5 years 73 days
Exercisable at December 31, 2015	$ 53,368
Expected to vest after December 31, 2015	368,458
Expected to vest after December 31, 2015	$ 31.45
Expected to vest after December 31, 2015	7 years 146 days
Expected to vest after December 31, 2015	$ 418
Options granted	35,000	629,775	621,100
Options granted	$ 40.20	$ 32.72	$ 18.16
Options forfeited	(63,749)	(204,348)	(520,139)
Options forfeited	$ 22.75	$ 20.42	$ 15.38
Options exercised	(1,170,330)	(2,794,225)	(2,229,873)
Options exercised	$ 12.19	$ 15.20	$ 10.85
Outstanding Balance	3,766,868	4,965,947	7,334,745
Outstanding Balance	$ 13.28	$ 12.96	$ 12.33
Outstanding Balance	$ 53,865