Note 10 - Long-Term Debt Interest Expense Recognized Related to Convertible Debt (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Convertible Senior Notes Due 2017
Schedule of Interest Expense Recognized Related to Convertible Debt [Line Items]
Contractual interest expense of convertible debt	$ 456	$ 3,375	$ 6,953	$ 10,125
Amortization of debt issuance costs	43	308	659	912
Amortization of debt discount	808	5,441	11,910	15,939
Total interest expense for convertible debt	1,307	9,124	19,522	26,976
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	6,750	6,750
Amortization of debt issuance costs	317	322	975	957
Amortization of debt discount	3,146	2,980	9,342	8,803
Total interest expense for convertible debt	$ 5,713	$ 5,552	$ 17,067	$ 16,510