Quarterly report pursuant to Section 13 or 15(d)

License and Collaboration Agreements - Additional Information (Detail)

v3.19.1
License and Collaboration Agreements - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended
Oct. 31, 2015
Jun. 30, 2015
Mar. 31, 2019
Dec. 31, 2018
Mar. 31, 2018
Sep. 30, 2016
Related Party Transaction [Line Items]            
Research and development expense     $ 48,668,000   $ 28,460,000  
Contractual obligations due MSK and QIMR     0 $ 0    
MSK Agreements            
Related Party Transaction [Line Items]            
Research and development expense   $ 4,500,000   $ 12,500,000    
Potential milestone payments payable     $ 33,000,000      
License Agreement | QIMR Berghofer            
Related Party Transaction [Line Items]            
Research and development expense $ 3,000,000         $ 3,300,000