Quarterly report pursuant to Section 13 or 15(d)

Revenue - Narrative (Details)

v3.19.1
Revenue - Narrative (Details)
€ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Feb. 08, 2018
USD ($)
swap_option
research_program
performance_obligation
license
May 02, 2017
USD ($)
performance_obligation
Feb. 27, 2017
USD ($)
Jan. 04, 2017
EUR (€)
bispecific_therapeutic_program
performance_obligation
extension_option
license
Jan. 04, 2017
USD ($)
bispecific_therapeutic_program
performance_obligation
extension_option
product
license
Feb. 28, 2019
EUR (€)
Feb. 28, 2019
USD ($)
Dec. 31, 2018
EUR (€)
Dec. 31, 2018
USD ($)
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Disaggregation of Revenue [Line Items]                          
Revenue recognized from contract with customer                   $ 4,300,000      
Revenue                   7,534,000 $ 3,444,000    
Additions to deferred revenue                   0      
Seattle Genetics                          
Disaggregation of Revenue [Line Items]                          
Remaining performance obligation                   26,400,000      
AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Remaining performance obligation                   39,500,000      
Research collaboration agreement term   5 years                      
Capitalized contract costs   $ 1,600,000               1,000,000      
Amortization of capitalized contract costs                   100,000      
Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Remaining performance obligation                   31,600,000      
Capitalized contract costs         $ 500,000         500,000      
Les Laboratoires Servier and Institut de Recherches Internationales Servier | Research and Development Services                          
Disaggregation of Revenue [Line Items]                          
Research collaboration agreement term       3 years 3 years                
ASKA Pharmaceutical Co. Ltd.                          
Disaggregation of Revenue [Line Items]                          
Deferred revenue                   2,900,000      
Capitalized contract costs     $ 300,000             300,000      
Evaluation period     60 days                    
License and Collaboration Agreement | Seattle Genetics                          
Disaggregation of Revenue [Line Items]                          
Period after effective date agreements may be terminated 12 months                        
Contract termination advance notice period 90 days                        
Agreement termination advance notice period if marketing approval obtained 180 days                        
Agreement termination notice period upon material breach by the Company 90 days                        
Contract termination due to material breach, additional notice period if the breach is not susceptible 90 days                        
Number of licenses | license 3                        
Number of swap options | swap_option 2                        
Number of performance obligations | performance_obligation 6                        
Number of research programs | research_program 3                        
License and Collaboration Agreement | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Period after effective date agreements may be terminated   12 months                      
Contract termination advance notice period   90 days                      
Agreement termination advance notice period if marketing approval obtained   180 days                      
Agreement termination notice period upon material breach by the Company   180 days                      
Agreement termination notice period upon breach of payment obligations by the Company   30 days                      
Contract termination due to material breach, additional notice period if the breach is not susceptible   180 days                      
Number of performance obligations | performance_obligation   16                      
Performance obligation period   12 months                      
License and Collaboration Agreement | Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Number of licenses | license       5 5                
Number of performance obligations | performance_obligation       14 14                
Number of research programs | bispecific_therapeutic_program       5 5                
Sales Milestones | Seattle Genetics                          
Disaggregation of Revenue [Line Items]                          
Current deferred revenue                   4,800,000      
Non-current deferred revenue                   17,300,000      
Sales Milestones | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Current deferred revenue                   13,100,000      
Non-current deferred revenue                   18,200,000      
Sales Milestones | Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Deferred revenue                   7,400,000      
Non-current deferred revenue                   $ 24,200,000      
Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Period after effective date agreements may be terminated       12 months 12 months                
Contract termination advance notice period       180 days 180 days                
Milestone payments           € 1.5 $ 1,700,000 € 0.5 $ 600,000        
Number of collaboration products | product         4                
Strategic Partnerships and Other License Agreements | ASKA Pharmaceutical Co. Ltd.                          
Disaggregation of Revenue [Line Items]                          
Agreement termination notice period upon breach of payment obligations by the Company     30 days                    
Milestone payments                       $ 0 $ 0
Upfront Payment | Seattle Genetics                          
Disaggregation of Revenue [Line Items]                          
Research and development services $ 4,900,000                        
Deferred revenue 1,200,000,000                        
Upfront Payment | Seattle Genetics | License fees                          
Disaggregation of Revenue [Line Items]                          
Revenue $ 30,000,000                        
Upfront Payment | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Allocable arrangement consideration   $ 45,000,000                      
Upfront Payment | ASKA Pharmaceutical Co. Ltd.                          
Disaggregation of Revenue [Line Items]                          
Upfront option payment received     $ 2,750,000                    
Upfront Payment | Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier | License fees                          
Disaggregation of Revenue [Line Items]                          
Revenue       € 30.0 $ 32,000,000                
Additional Other Research Services | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Allocable arrangement consideration   4,700,000                      
Estimated Development and Manufacturing Services | Upfront Payment | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Allocable arrangement consideration   14,200,000                      
Milestone Payments | Upfront Payment | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Allocable arrangement consideration   12,500,000                      
Estimated Phase 2a Services | Upfront Payment | AstraZeneca                          
Disaggregation of Revenue [Line Items]                          
Allocable arrangement consideration   $ 4,700,000                      
Extension Term | Les Laboratoires Servier and Institut de Recherches Internationales Servier | Research and Development Services                          
Disaggregation of Revenue [Line Items]                          
Research collaboration agreement term       1 year 1 year                
Number of agreement extension options | extension_option       2 2                
Minimum | Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Agreement termination notice period upon material breach by the Company       90 days 90 days                
Maximum | Strategic Partnerships and Other License Agreements | Les Laboratoires Servier and Institut de Recherches Internationales Servier                          
Disaggregation of Revenue [Line Items]                          
Agreement termination notice period upon material breach by the Company       120 days 120 days