Collaboration, License, and Other Agreements - Sanofi, Antibody Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Apr. 01, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues		$ 3,452.8	$ 2,294.0	$ 11,120.0	$ 6,074.2
Sanofi Collaboration Agreement, Antibody
Disaggregation of Revenue [Line Items]
Levels of twelve-month sales at which sales milestone payments would be received				$ 1,500.0	$ 1,000.0
Period for achieving sales target for milestone payment, rolling basis				12 months	12 months
Remaining amount of sales milestone payments if total sales achieve specific levels				$ 150.0
Sanofi Collaboration Agreement, Antibody | First Sales Milestone
Disaggregation of Revenue [Line Items]
Revenues			$ 50.0
Sanofi Collaboration Agreement, Antibody | Second Sales Milestone
Disaggregation of Revenue [Line Items]
Revenues		$ 50.0
Sanofi Collaboration Agreement, Antibody | Minimum
Disaggregation of Revenue [Line Items]
Percentage of trial costs required to be funded by collaborating party				80.00%
Sanofi Collaboration Agreement, Antibody | Maximum
Disaggregation of Revenue [Line Items]
Percentage of trial costs required to be funded by collaborating party				100.00%
Praluent Agreement
Disaggregation of Revenue [Line Items]
Royalty percentage to be received on net product sales outside of the United States	5.00%
Percentage of damages company is responsible for	50.00%
Praluent Agreement | Sanofi
Disaggregation of Revenue [Line Items]
Percentage of royalty payment that can be used to offset litigation proceedings (up to)	50.00%