License, Research and Collaboration Agreements - Rush Agreement - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Rush Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount or royalty payments made or accrued	$ 59.9	$ 48.1	$ 37.4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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