Intangible Assets and Goodwill - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Finite-lived intangible asset
Accumulated Amortization	$ (7,623)		$ (7,399)
Total Intangible Assets
Gross carrying amount of total intangible assets, net	74,990		74,990
Net carrying amount of total intangible assets, net	48,690		$ 67,591
Impairment	(18,677)
Amortization of Intangible Assets	$ 224	$ 224
License Rights
Finite-lived intangible asset
Estimated Life	16 years		16 years
Gross carrying amount finite-lived	$ 14,500		$ 14,500
Accumulated Amortization	(7,623)		(7,399)
Net carrying amount finite-lived			7,101
Total Intangible Assets
Impairment	(6,877)
IPR&D
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	60,490		60,490
Net carrying amount of indefinite-lived	48,690		$ 60,490
Total Intangible Assets
Impairment	$ (11,800)

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value portion of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit.

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Amount before accumulated amortization of intangible assets, excluding goodwill.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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