Collaboration Agreements - Schedule of Contract Balances, Antibody Collaboration (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 345.4	$ 226.4
Sanofi Collaboration Agreement, Antibody
Disaggregation of Revenue [Line Items]
Accounts receivable	332.5	138.2
Deferred revenue	$ 377.0	$ 236.1

Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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