Acquisitions - Concert Pharmaceuticals (Details) - Concert Pharmaceuticals $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
| |
| Business Acquisition [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 |
| Collaborative funding | 160.0 |
| Collaborative arrangement, purchase price | 165.1 |
| Collaborative arrangement, transaction costs | $ 5.1 |