Note 10 - Long-Term Debt Interest Expense Recognized Related to Convertible Debt (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Convertible Senior Notes Due 2017
Schedule of Interest Expense Recognized Related to Convertible Debt [Line Items]
Contractual interest expense of convertible debt	$ 3,122	$ 3,375	$ 6,497	$ 6,750
Amortization of debt issuance costs	298	304	616	604
Amortization of debt discount	5,394	5,312	11,102	10,498
Total interest expense for convertible debt	8,814	8,991	18,215	17,852
Convertible Senior Notes Due 2019
Schedule of Interest Expense Recognized Related to Convertible Debt [Line Items]
Contractual interest expense of convertible debt	2,250	2,250	4,500	4,500
Amortization of debt issuance costs	330	319	658	635
Amortization of debt discount	3,123	2,934	6,196	5,823
Total interest expense for convertible debt	$ 5,703	$ 5,503	$ 11,354	$ 10,958