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 6 Months Ended 12 Months Ended
May 10, 2017
USD ($)
Jan. 31, 2014
USD ($)
Program
Jun. 30, 2012
Targets
Jan. 31, 2012
USD ($)
Targets
Jun. 30, 2017
USD ($)
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
Product
Jun. 30, 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         $ 14,984,000 $ 19,454,000 $ 27,926,000 $ 34,720,000  
Pfizer [Member]                  
Research and Development Arrangement, Contract to Perform for Others [Line Items]                  
Revenues under agreement $ 70,000,000                
Milestone revenue receivable 475,000,000                
Milestone payments received             $ 0    
Number of products approved | Product             0    
Royalty revenues             $ 0    
Research program to develop laboratory research reagents             32 months    
Deferred revenue         66,200,000   $ 66,200,000    
Recognition of upfront fee         3,800,000        
Bioverativ Inc [Member]                  
Research and Development Arrangement, Contract to Perform for Others [Line Items]                  
Revenues under agreement   $ 20,000,000              
Milestone payments received             $ 0    
Number of products approved | Product             0    
Royalty revenues             $ 0    
Research program to develop laboratory research reagents             44 months    
Deferred revenue         5,500,000   $ 5,500,000    
Recognition of upfront fee         442,000 608,000 884,000 1,216,000  
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              
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         2,900,000 2,100,000 $ 4,500,000 4,100,000  
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         1,200,000   $ 1,200,000    
Recognition of upfront fee         583,000 541,000 1,167,000 1,083,000  
Research and development         $ 0 $ 300,000 $ 100,000 $ 700,000  
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
Maximum [Member] | SB-525 [Member] | Pfizer [Member]                  
Research and Development Arrangement, Contract to Perform for Others [Line Items]                  
Milestone revenue receivable 300,000,000                
Maximum [Member] | Other Products [Member] | Pfizer [Member]                  
Research and Development Arrangement, Contract to Perform for Others [Line Items]                  
Milestone revenue receivable $ 175,000,000