Annual report pursuant to Section 13 and 15(d)

Research and Development Agreements - Additional Information (Detail)

v3.20.4
Research and Development Agreements - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 12 Months Ended 107 Months Ended
Nov. 30, 2019
Jul. 31, 2019
Sep. 30, 2018
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Nov. 30, 2019
Jun. 23, 2017
Research And Development Collaboration Agreements [Line Items]                
Common stock, shares issued         49,984,333 45,589,157    
Common stock, par value         $ 0.001 $ 0.001    
Revenue from grant         $ 18,845 $ 22,270    
Grant                
Research And Development Collaboration Agreements [Line Items]                
Revenue from grant         3,210 2,771    
Takeda Pharmaceuticals Inc                
Research And Development Collaboration Agreements [Line Items]                
Purchase price per share               $ 6.8423
CPRIT Agreement | Cancer Prevention and Research Institute of Texas                
Research And Development Collaboration Agreements [Line Items]                
Product development grant awarded     $ 15,200          
CPRIT Agreement | Cancer Prevention and Research Institute of Texas | ETB MT-3724                
Research And Development Collaboration Agreements [Line Items]                
Aggregate proceeds received from award granted             $ 10,600  
Revenue from grant         20,000      
Grants Receivable         0      
Grant Agreements | Grants Revenue Receivable                
Research And Development Collaboration Agreements [Line Items]                
Reimbursement amounts submitted in excess of amounts received are recorded as receivables         0 7,100    
Takeda Development Agreement                
Research And Development Collaboration Agreements [Line Items]                
Total transaction price         29,800      
Upfront payment         30,000      
Development milestone payment that is achievable       $ 10,000        
Expected co-share payments payable         10,200      
Deferred revenue         1,300 6,100    
Takeda Development Agreement | Clinical Development and Regulatory Milestones                
Research And Development Collaboration Agreements [Line Items]                
Milestone payments receivable if option is exercised   $ 307,500            
Takeda Development Agreement | Sales Milestone                
Research And Development Collaboration Agreements [Line Items]                
Milestone payments receivable if option is exercised   $ 325,000            
Takeda Multi Target Agreement | Takeda Pharmaceuticals Inc                
Research And Development Collaboration Agreements [Line Items]                
Milestone payments receivable if option is exercised         397,000      
Deferred revenue         2,600 3,100    
Cumulative payments received         5,000      
Aggregate milestone payments upon exercise of option to license ETBS         30,000      
Takeda Multi Target Agreement | Takeda Pharmaceuticals Inc | Maximum                
Research And Development Collaboration Agreements [Line Items]                
Contractual contingency fees         10,000      
Commercial milestone payment         150,000      
Vertex Collaboration Agreement                
Research And Development Collaboration Agreements [Line Items]                
Milestone payments receivable if option is exercised $ 180,000              
Upfront payment 38,000              
Deferred revenue         $ 18,400 $ 27,500    
Upfront payment, cash 23,000              
Upfront payment, equity method investments $ 15,000           $ 15,000  
Common stock, shares issued 1,666,666           1,666,666  
Common stock, par value $ 0.001           $ 0.001  
Vertex Collaboration Agreement | Common Stock                
Research And Development Collaboration Agreements [Line Items]                
Purchase price per share $ 9.00           $ 9.00  
Fair value of allocated consideration $ 4,500              
Vertex Collaboration Agreement | ETBs                
Research And Development Collaboration Agreements [Line Items]                
Aggregate milestone payments upon exercise of option to license ETBS 22,000           $ 22,000  
Vertex Collaboration Agreement | Sales Milestone                
Research And Development Collaboration Agreements [Line Items]                
Milestone payments receivable if option is exercised $ 70,000