Quarterly report pursuant to Section 13 or 15(d)

Major Customers, Partnerships and Strategic Alliances - Additional Information (Detail)

v3.7.0.1
Major Customers, Partnerships and Strategic Alliances - Additional Information (Detail)
1 Months Ended 3 Months Ended 12 Months Ended
Jan. 31, 2014
USD ($)
Program
Jun. 30, 2012
Targets
Jan. 31, 2012
USD ($)
Targets
Mar. 31, 2017
USD ($)
Product
Mar. 31, 2016
USD ($)
Dec. 31, 2014
USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]            
Number of research programs | Program 2          
Research and development       $ 12,942,000 $ 15,266,000  
Bioverativ Inc [Member]            
Research and Development Arrangement, Contract to Perform for Others [Line Items]            
Revenues under agreement $ 20,000,000          
Potential amount eligible to receive for certain milestones 115,800,000          
Potential amount to be funded for achievement of specified commercialized and sales milestones 160,500,000          
Milestone revenue receivable 276,300,000          
Milestone payments received       $ 0    
Number of products approved | Product       0    
Royalty revenues       $ 0    
Research program to develop laboratory research reagents       44 months    
Deferred revenue       $ 6,000,000    
Bioverativ Inc [Member] | Sickle cell disease [Member]            
Research and Development Arrangement, Contract to Perform for Others [Line Items]            
Milestone revenue receivable 7,500,000          
Bioverativ Inc [Member] | Beta-thalassemia Project [Member]            
Research and Development Arrangement, Contract to Perform for Others [Line Items]            
Milestone revenue receivable $ 6,000,000          
Research and development       $ 1,600,000 2,000,000  
Shire AG [Member]            
Research and Development Arrangement, Contract to Perform for Others [Line Items]            
Revenues under agreement     $ 13,000,000      
Research program to develop laboratory research reagents       6 years    
Deferred revenue       $ 1,800,000    
Research and development       $ 100,000 $ 400,000  
Aggregate number of gene targets | Targets     7      
Number of initial gene targets | Targets     4      
Number of gene targets | Targets   5        
Number of additional gene targets | Targets   2        
Recognition of milestone           $ 1,000,000