Collaborative Arrangements and Acquisitions - Concert Pharmaceuticals (Details) - Concert Pharmaceuticals $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, development and commercialization rights potential maximum milestone payments	$ 160.0
Collaborative arrangement, additional maximum milestone payments based on regulatory approval	$ 90.0

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.

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