Significant Agreements Juno Therapeutics Collaboration Agreement (Details)
$ in Thousands
1 Months Ended 3 Months Ended
May. 26, 2015
item
May. 31, 2015
USD ($)
item
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Collaboration revenue     $ 805  
Deferred revenue     25,479 $ 25,321
Accounts receivable     1,108 $ 1,019
Juno Therapeutics        
Collaboration revenue     800  
Deferred revenue     25,500  
Accounts receivable     1,000  
Collaboration and License Agreement | Juno Therapeutics        
Number of research areas | item   3    
Agreement term 5 years      
Extensions | item 2      
Extension period 1 year      
Upfront fee received   $ 25,000    
Potential research and development funding   $ 22,000    
Number of additional licenses | item   3    
Potential fee receivable for each gene target licensed   $ 2,500    
Potential development milestone payments   77,500    
Potential regulatory milestone payments   80,000    
Potential commercial milestone payments   $ 75,000    
Next possible milestone payment     $ 2,500  
Number of options to purchase Development and Commercialization License | item   3    
Number of deliverables | item   6    
Number of accounting units | item   11    
Number of accounting units for Development and Commercialization License | item   3    
Number of accounting units for discount deliverables | item   6    
Allocable arrangement consideration - upfront payment   $ 25,000    
Allocable arrangement consideration - research support   20,000    
Allocable arrangement consideration - specialized material costs   2,000    
Allocable arrangement consideration - aggregate arrangement consideration   47,000    
Allocable arrangement consideration - R&D Services Unit of Accounting   16,700    
Allocable arrangement consideration - Development and Commercialization License for the first research area   9,300    
Allocable arrangement consideration - Development and Commercialization License for the second research area   15,400    
Allocable arrangement consideration - Development and Commercialization License for the third research area   200    
Allocable arrangement consideration - first Discount Deliverable for the first research area   700    
Allocable arrangement consideration - second Discount Deliverable for the first research area   400    
Allocable arrangement consideration - third Discount Deliverable for the first research area   200    
Allocable arrangement consideration - first Discount Deliverable for the second research area   2,000    
Allocable arrangement consideration - second Discount Deliverable for the second research area   1,300    
Allocable arrangement consideration - third Discount Deliverable for the second research area   800    
Allocable arrangement consideration -JRC Deliverable   $ 0