Facilities (Details) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 ft² renewal_option
Lessee, Lease, Description [Line Items]
Right of use assets	$ 256.8	$ 256.8
Operating lease liability	268.5	$ 268.5
Cell and Genetic Therapies Lease
Lessee, Lease, Description [Line Items]
Area of real estate property (in square feet) | ft²			269,000
Lease agreement initial term			15 years
Number of optional renewal terms | renewal_option			2
Optional renewal term length			10 years
Boston Continuous Manufacturing
Lessee, Lease, Description [Line Items]
Payments to purchase buildings in cash	$ 155.3
Property equipment, useful life		40 years