Annual report pursuant to Section 13 and 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 86 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
Sep. 30, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2018
Nov. 30, 2017
Oct. 31, 2016
Research And Development Collaboration Agreements [Line Items]                            
Research and development revenues from collaboration agreements                   $ 7,283,000 $ 2,408,000      
Deferred revenue                   28,901,000 2,765,000 $ 28,901,000    
Grant                            
Research And Development Collaboration Agreements [Line Items]                            
Revenue from grant                   6,000,000 987,000      
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    
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                   3,900,000        
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      
Deferred revenue                   24,800,000   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                   196,000 500,000      
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]                            
Aggregate purchase price     $ 20,000,000                      
Takeda Pharmaceuticals Inc | Takeda Collaboration Agreement                            
Research And Development Collaboration Agreements [Line Items]                            
Upfront payment for technology access fees and cost reimbursement                           $ 2,000,000
Research and development revenues from collaboration agreements                   92,000 1,900,000      
Takeda Pharmaceuticals Inc | Takeda Individual Project Agreement                            
Research And Development Collaboration Agreements [Line Items]                            
Research and development revenues from collaboration agreements                   2,200,000 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 Multi Target Agreement                            
Research And Development Collaboration Agreements [Line Items]                            
Research and development revenues from collaboration agreements                   901,000 0      
Upfront payment received                     1,000,000      
Deferred revenue                   4,100,000   4,100,000    
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