Note 2 - Summary of Significant Accounting Policies (Details) - Stock Option Activity - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Stock Option Activity [Abstract]
Options outstanding	4,143,084	4,965,947
Options outstanding - weighted average exercise price	$ 12.90	$ 12.96
Options granted	35,000
Options granted	$ 40.20
Options forfeited	(38,766)
Options forfeited	$ 22.67
Options exercised	(819,097)
Options exercised	$ 13.98
Exercisable at June 30, 2015	3,595,175
Exercisable at June 30, 2015	$ 10.15
Exercisable at June 30, 2015	5 years 219 days
Exercisable at June 30, 2015	$ 104,071