Note 2 - Summary of Significant Accounting Policies (Details) - Stock Option Activity (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Stock Option Activity [Abstract]
Outstanding at December 31, 2013	7,334,745
Outstanding at December 31, 2013	$ 12.33
Outstanding at September 30, 2014	5,417,848
Outstanding at September 30, 2014	$ 13.06
Exercisable at September 30, 2014	3,984,890
Exercisable at September 30, 2014	$ 10.46
Exercisable at September 30, 2014	6 years 109 days
Exercisable at September 30, 2014	$ 88,822
Options granted	597,275
Options granted	$ 32.56
Options forfeited	(176,204)
Options forfeited	$ 20.79
Options exercised	(2,337,968)
Options exercised	$ 15.15