Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Tax Cuts and Jobs Act of 2017 - change in tax rate, provisional income tax benefit			$ 5,900	$ 155,100
Income tax provision (benefit)		$ (73,154)	$ 80,162	(47,740)
Discrete tax benefit, intra-entity intellectual property asset transfer	$ 112,300	$ 112,300
Tax Cuts and Jobs Act of 2017 - net benefit of the impacts				$ 148,800
Effective income tax rate (as a percent)		(16.10%)	15.10%	(10.80%)
Statutory income tax rate (as a percent)		12.50%	12.50%	12.50%
Increase (decrease) in valuation allowance		$ 5,100	$ 9,100	$ (1,000)
Deferred tax assets, valuation allowance		66,307	61,237
Cumulated unremitted earnings of overseas subsidiaries		1,600,000	1,200,000
Unrecognized tax benefits, accrued interest and penalties		7,400	6,300
Unrecognized tax benefits that would impact the effective tax rate		$ 78,800	$ 78,500
Ireland
Operating Loss Carryforwards [Line Items]
Statutory income tax rate (as a percent)		12.50%	12.50%	12.50%
Ireland | Ireland
Operating Loss Carryforwards [Line Items]
NOL carryforwards		$ 78,400
U.S. Federal
Operating Loss Carryforwards [Line Items]
NOL carryforwards		273,000
Tax credit carryforwards		173,100
U.S. Federal | Celator Pharmaceuticals, Inc.
Operating Loss Carryforwards [Line Items]
NOL carryforwards					$ 204,700
U.S. Federal | Cavion Inc
Operating Loss Carryforwards [Line Items]
NOL carryforwards		18,700
U.S. State
Operating Loss Carryforwards [Line Items]
NOL carryforwards		94,000
Tax credit carryforwards		11,300
Foreign Tax Authorities
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance		15,700		$ 5,900
Tax credit carryforwards		41,700
Foreign Tax Authorities | Luxembourg
Operating Loss Carryforwards [Line Items]
NOL carryforwards		45,200
Foreign Tax Authorities | United Kingdom
Operating Loss Carryforwards [Line Items]
NOL carryforwards		46,200
Foreign Tax Authorities | Malta
Operating Loss Carryforwards [Line Items]
NOL carryforwards		24,600
Valuation Allowance, Operating Loss Carryforwards
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance		6,300	$ 11,200	(6,600)
Tax Cuts And Jobs Act Of 2017, Foreign Tax Credits
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance			25,700
Utilization Of NOL Carryforwards Which Previously Carried Valuation Allowance
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance				$ (9,100)
Tax Year 2012 And 2013 | French Tax Authorities
Operating Loss Carryforwards [Line Items]
Proposed additional tax including interest and penalties		42,000
Tax Year 2015, 2016 and 2017 | French Tax Authorities
Operating Loss Carryforwards [Line Items]
Proposed additional tax including interest and penalties		$ 12,000
Her Majesty's Revenue and Customs (HMRC) | Foreign Tax Authorities
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance			$ (10,900)