v3.7.0.1
Commitments and Contingencies (Narrative) (Details)
$ in Millions
3 Months Ended
Mar. 31, 2017
USD ($)
Commitments and Contingencies [Line Items]  
Other Commitment, Potential Payment $ 27
Arbutus Agreement [Member]  
Commitments and Contingencies [Line Items]  
Research and development expense, upfront payment 8
Research and development arrangement, potential payment 75
Lonza Agreement [Member]  
Commitments and Contingencies [Line Items]  
Remaining total commitments with Lonza $ 1,126