Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of basic and diluted net income (loss) per share
Net income (loss)	$ (20,584)	$ 1,458	$ 25,578	$ (7,191)
Weighted average common shares outstanding	33,223	21,984	30,379	21,912
Effect of dilutive securities:
Warrants (in shares)			3,015
Stock options and RSUs (in shares)		369	1,568
Convertible 2.5% notes (in shares)		1,114
Shares used in calculating dilutive net income (loss) per share (in shares)	33,223	23,467	34,962	21,912
Net income (loss) per share:
Basic (in dollars per share)	$ (0.62)	$ 0.07	$ 0.84	$ (0.33)
Diluted (in dollars per share)	$ (0.62)	$ 0.06	$ 0.73	$ (0.33)
Anti-dilutive securities (in shares)	18,465	15,952	8,330	18,605
Employee and Non Employee Stock Option
Net income (loss) per share:
Anti-dilutive securities (in shares)	2,989	2,013	791	3,081
Employee and Non Employee Restricted Stock Units
Net income (loss) per share:
Anti-dilutive securities (in shares)	712	289	157	760
Warrants
Net income (loss) per share:
Anti-dilutive securities (in shares)	7,382	7,382		7,382
Convertible Debt
Net income (loss) per share:
Anti-dilutive securities (in shares)	7,382	6,268	7,382	7,382