Intangible Assets and Goodwill - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 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
Non-cash impairment charges of intangible assets		$ 11,800		18,677
Net carrying amount of total intangible assets, net	48,690			48,690		$ 67,591
Amortization of Intangible Assets	0		$ 224	$ 224	$ 448
Non cash impairment of finite-lived intangible assets		$ (6,900)
License Rights
Finite-lived intangible asset
Estimated Life				16 years		16 years
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
Non-cash impairment charges of intangible assets				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
Non-cash impairment charges of intangible assets				$ 11,800