Intangible Assets and Goodwill - Additional Information (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 3,100,000		$ 6,500,000	$ 11,600,000	$ 19,300,000
Future amortization expense, remainder of fiscal year	5,400,000			5,400,000
Future amortization expense, 2018	21,400,000			21,400,000
Future amortization expense, 2019	21,400,000			21,400,000
Future amortization expense, 2020	21,400,000			21,400,000
Future amortization expense, 2021	21,400,000			21,400,000
Future amortization expense, 2022	21,400,000			21,400,000
Future amortization expense, thereafter	173,600,000			173,600,000
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	285,965,000			285,965,000		$ 361,601,000
Indefinite-lived intangible assets	0			0		253,620,000
Increase (decrease) in carrying amount of goodwill				0
In-process research & development
Finite-Lived Intangible Assets [Line Items]
Reclassification of IPR&D assets	(188,600,000)
Indefinite-lived intangible assets	0			0		253,620,000
Developed product rights, net
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	285,965,000			285,965,000		334,614,000
Product licenses, net
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	$ 0			$ 0		$ 26,987,000
Not discontinued operations, discontinuation and market withdrawal | Ionsys | Developed product rights, net
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets		$ 226,500,000
Not discontinued operations, discontinuation and market withdrawal | Ionsys | Product licenses, net
Finite-Lived Intangible Assets [Line Items]
Impairment of finite-lived intangible assets		26,200,000
Not discontinued operations, discontinuation and market withdrawal | MDCO-700 | In-process research & development
Finite-Lived Intangible Assets [Line Items]
Impairment of indefinite-lived intangible assets		65,000,000
Indefinite-lived intangible assets		0
Not discontinued operations, discontinuation and market withdrawal | MDCO-700 | Product licenses, net
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		$ 0