Annual report pursuant to Section 13 and 15(d)

Quarterly Financial Information (unaudited) (Parenthetical) (Details)

v3.8.0.1
Quarterly Financial Information (unaudited) (Parenthetical) (Details) - Novartis [Member] - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Sep. 30, 2017
Jun. 30, 2017
Dec. 31, 2017
Error Corrections And Prior Period Adjustments Restatement [Line Items]      
License fee revenue recognized $ 35.4    
Collaborative Arrangement [Member]      
Error Corrections And Prior Period Adjustments Restatement [Line Items]      
Milestone received under the collaboration agreement   $ 10.0 $ 10.0