Collaboration and License Agreements - Schedule of Accounts Receivable and Deferred Revenue Information, IO Collaboration (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 226.4	$ 193.7
Sanofi Collaboration Agreement, Immuno-oncology
Disaggregation of Revenue [Line Items]
Accounts receivable	77.9	59.3
Deferred revenue	$ 289.9	$ 440.0

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

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