Quarterly report pursuant to Section 13 or 15(d)

Research and Development Agreements - Additional Information (Detail)

v3.19.1
Research and Development Agreements - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 12 Months Ended 89 Months Ended
Sep. 18, 2018
Aug. 31, 2017
Jun. 23, 2017
Oct. 31, 2018
Jul. 31, 2018
Jun. 30, 2018
Sep. 30, 2016
Nov. 30, 2011
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2019
Dec. 31, 2018
Nov. 30, 2017
Oct. 31, 2016
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 $ 6,413,000 $ 231,000          
Deferred revenue                 21,372,000     $ 21,372,000 $ 28,901,000    
Grant                              
Research And Development Collaboration Agreements [Line Items]                              
Revenue from grant                 595,000,000,000 251,000          
Grant Agreements | Other Current Assets                              
Research And Development Collaboration Agreements [Line Items]                              
Reimbursement amounts submitted in excess of amounts received are recorded as receivables                 4,100,000     4,100,000 0    
CPRIT Agreement | Grant                              
Research And Development Collaboration Agreements [Line Items]                              
Cancer research grant contract award $ 15,200,000                            
Takeda Development Agreement                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 6,100,000            
Upfront payment received       $ 30,000,000                      
total transaction price                 29,300,000            
Upfront payment                 30,000,000            
Probable development milestone payment that is achievable                 10,000,000            
Expected co share payment receivable                 10,700,000     10,700,000      
Research and development revenue                 0 0          
Deferred revenue                 17,500,000     17,500,000 24,800,000    
Takeda Development Agreement | Clinical Development and Regulatory Milestones                              
Research And Development Collaboration Agreements [Line Items]                              
Milestone payments receivable if option is exercised                 307,500,000            
Milestone payments receivable if option is not exercised                 162,500,000            
Takeda Development Agreement | Sales Milestone                              
Research And Development Collaboration Agreements [Line Items]                              
Milestone payments receivable if option is exercised                 325,000,000            
Milestone payments receivable if option is not exercised                 175,000,000            
Other Collaboration Agreements                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 0 68,000          
Other Collaboration Agreements | ETBs                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements             $ 500,000                
Contingent milestone payment upon delivery and acceptance of additional ETB materials                           $ 250,000  
Takeda Pharmaceuticals Inc                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 6,413,000 163,000          
Deferred revenue                 21,372,000     21,372,000 28,901,000    
Aggregate purchase price     $ 20,000,000                        
Takeda Pharmaceuticals Inc | Takeda Collaboration Agreement                              
Research And Development Collaboration Agreements [Line Items]                              
Payment for technology access fees and cost reimbursement                             $ 2,000,000
Research and development revenues from collaboration agreements                 0 11,000          
Takeda Pharmaceuticals Inc | Takeda Individual Project Agreement                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 54,000 0          
Additional research and development revenue entitled to potentially receive           $ 2,200,000                  
Increase in transaction consideration related to research services         $ 1,100,000                    
Takeda Pharmaceuticals Inc | Takeda Development Agreement                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 6,114,000 0          
Takeda Pharmaceuticals Inc | Takeda Multi Target Agreement                              
Research And Development Collaboration Agreements [Line Items]                              
Research and development revenues from collaboration agreements                 245,000 $ 152,000          
Upfront payment received                     $ 1,000,000        
Deferred revenue                 3,900     3,900 $ 4,100    
Additional contingent milestone payments upon designation of each of two targets                     $ 2,000,000        
Milestone payment received                 5,000,000            
Aggregate milestone payments upon exercise of option to license ETBS                 25,000,000     25,000,000      
Additional preclinical, clinical development and commercialization milestone payments entitled to potentially receive                 397,000,000     397,000,000      
Contractual contingency fees                 10,000,000            
Commercial milestone payment                 150,000,000            
Proceeds from signing of stock purchase agreement                 $ 20,000,000            
Aggregate purchase price   $ 20,000,000                          
Cancer Prevention and Research Institute of Texas | Grant Agreements | ETB MT-3724                              
Research And Development Collaboration Agreements [Line Items]                              
Product development grant awarded               $ 10,600,000              
Aggregate proceeds received from award granted                       $ 9,500,000