Note 10 - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Beginning balance (in shares)	5,030,000
Beginning balance (in dollars per share)	$ 17.37
Granted (in shares)	983,000
Granted (in dollars per share)	$ 13.90
Exercised (in shares)	(10,000)	(400,000)
Exercised (in dollars per share)	$ 2.85
Forfeitures (in shares)	(27,000)
Forfeitures (in dollars per share)	$ 18.88
Expired (in shares)	(69,000)
Expired (in dollars per share)	$ 24.63
Ending balance (in shares)	5,907,000
Ending balance (in dollars per share)	$ 16.73
Ending balance	5 years 76 days
Ending balance	$ 6,503
Expected to vest (in shares)	3,830,000
Expected to vest (in dollars per share)	$ 15.77
Expected to vest	6 years 76 days
Expected to vest	$ 2,508
Exercisable (in shares)	1,990,000
Exercisable (in dollars per share)	$ 18.59
Exercisable	3 years 83 days
Exercisable	$ 3,944