Intangible Assets and Goodwill - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Finite-lived intangible asset
Accumulated Amortization	$ (7,623)			$ (7,623)		$ (7,399)
Total Intangible Assets
Gross carrying amount of total intangible assets, net	74,990			74,990		74,990
Accumulated Impairments		$ (11,800)	$ (13,000)	(18,677)	$ (13,000)
Net carrying amount of total intangible assets, net	48,690			48,690		67,591
Amortization of Intangible Assets	0		$ 224	224	$ 672
Non cash impairment of finite-lived intangible assets		$ (6,900)
License Rights
Finite-lived intangible asset
Gross carrying amount finite-lived	14,500			14,500		14,500
Accumulated Amortization	(7,623)			(7,623)		(7,399)
Net carrying amount finite-lived						7,101
Total Intangible Assets
Accumulated Impairments				(6,877)
IPR&D
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	60,490			60,490		60,490
Net carrying amount of indefinite-lived	$ 48,690			48,690		$ 60,490
Total Intangible Assets
Accumulated Impairments				$ (11,800)