Debt - Notes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Notes [Member]	Jan. 30, 2013 Notes [Member]
Debt Instrument [Roll Forward]
Embedded derivatives, beginning balance						$ 59,204
Convertible notes, beginning balance						175,000
Discount, beginning balance						(59,204)
Total, beginning balance						175,000
Amortization of debt discount					4,866
Debt discount write-off associated with conversion of debt					5,368
Change in fair value of embedded derivative	(27,793)	169	(38,691)	1,309	41,818
Embedded derivative, conversion					(1,199)
Convertible notes, conversion					(16,936)
Total, conversion					(18,135)
Embedded derivatives, ending balance					99,823	59,204
Convertible notes, ending balance					158,064	175,000
Discount, ending balance					(48,970)	(59,204)
Total, ending balance					$ 208,917	$ 175,000