Commitments and Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 376.9
Contingent liabilities	69.1
Contingent liabilities short-term	20.2
Clinical and Post Marketing Services
Commitments And Contingencies [Line Items]
Purchase commitments and other minimum contractual obligations	131.6
Third Party
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	65.5
Completed Programs | Third Party
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 239.7