Quarterly report pursuant to Section 13 or 15(d)

Revenues - Additional Information (Detail)

v3.4.0.3
Revenues - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Deferred Revenue Arrangement [Line Items]    
Revenues from product sales $ 0  
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Upfront Payment Arrangement [Member]    
Deferred Revenue Arrangement [Line Items]    
Collaboration agreement, license upfront payment $ 6,500,000  
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Research Services [Member]    
Deferred Revenue Arrangement [Line Items]    
Research collaboration agreement, estimated period 20 months  
Collaboration agreement, revenue recognized $ 1,200,000 $ 0
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Research Services [Member] | Extension Term [Member]    
Deferred Revenue Arrangement [Line Items]    
Research collaboration agreement, estimated period 5 years  
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Collaborative Arrangement [Member] | Maximum [Member]    
Deferred Revenue Arrangement [Line Items]    
Contractual agreement, potential payments $ 423,900,000  
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Collaborative Arrangement [Member] | Maximum [Member] | Development Milestones [Member]    
Deferred Revenue Arrangement [Line Items]    
Contractual agreement, potential payments 294,000,000  
FHoffmann La Roche Ltd And Hoffmann La Roche Inc [Member] | Collaborative Arrangement [Member] | Maximum [Member] | Sales Milestone Payments [Member]    
Deferred Revenue Arrangement [Line Items]    
Contractual agreement, potential payments $ 124,600,000