Quarterly report pursuant to Section 13 or 15(d)

Research and Development Agreements - Additional Information (Detail)

v3.20.2
Research and Development Agreements - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 107 Months Ended
Nov. 30, 2019
Jul. 31, 2019
Sep. 30, 2018
Jun. 30, 2020
Mar. 31, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Nov. 30, 2019
Dec. 31, 2019
Research And Development Collaboration Agreements [Line Items]                    
Common stock, shares issued       45,778,876     45,778,876     45,589,157
Common stock, par value       $ 0.001     $ 0.001     $ 0.001
Revenue from grant       $ 6,909   $ 5,447 $ 11,050 $ 12,455    
Grant                    
Research And Development Collaboration Agreements [Line Items]                    
Revenue from grant       869   $ 236 3,210 $ 831    
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             14,000      
Grants Receivable       5,900     5,900      
Grant Agreements | Grants Revenue Receivable                    
Research And Development Collaboration Agreements [Line Items]                    
Reimbursement amounts submitted in excess of amounts received are recorded as receivables       5,900     5,900     $ 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     10,200      
Deferred revenue       4,200     4,200     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                    
Research And Development Collaboration Agreements [Line Items]                    
Deferred revenue       2,900     2,900     3,100
Cumulative payments received             5,000      
Aggregate milestone payments upon exercise of option to license ETBS       30,000     30,000      
Additional preclinical, clinical development and commercialization milestone payment       397,000     397,000      
Takeda Multi Target Agreement | Takeda | 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       $ 23,000     $ 23,000     $ 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