Unaudited Quarterly Results (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues (losses)	$ (571)	$ 41,656	$ 1,477	$ 1,815	$ 2,968	$ 867	$ 1,801	$ 2,226	$ 44,377	$ 7,862	$ 14,048
Net income (loss)	(12,179)	36,975	(11,073)	(9,313)	(8,551)	(10,500)	(12,263)	(11,258)	4,410	(42,572)	(35,431)
Net income (loss) per share, basic (in dollars per share)	$ (0.18)	$ 0.53	$ (0.17)	$ (0.15)					$ 0.06	$ (0.76)	$ (1.02)
Net income (loss) per share, diluted (in dollars per share)	$ (0.18)	$ 0.51	$ (0.17)	$ (0.15)					$ 0.06	$ (0.76)	$ (1.02)
Net income (loss) per share - basic and diluted (in dollars per share)					$ (0.14)	$ (0.17)	$ (0.24)	$ (0.22)		$ (0.76)	$ (1.02)
Salix [Member]
Segment Reporting Information [Line Items]
Revenues (losses)		40,000
Fuji [Member]
Segment Reporting Information [Line Items]
Revenues (losses)				$ 1,000