Quarterly report pursuant to Section 13 or 15(d)

License and Collaboration Agreements - Additional Information (Detail)

v3.19.2
License and Collaboration Agreements - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended
Oct. 31, 2015
Jun. 30, 2015
Jun. 30, 2019
Dec. 31, 2018
Jun. 30, 2018
Sep. 30, 2016
Jun. 30, 2019
Jun. 30, 2018
Related Party Transaction [Line Items]                
Research and development expense     $ 52,251,000   $ 33,387,000   $ 100,919,000 $ 61,847,000
Contractual obligations due to MSK and QIMR     0 $ 0     0  
MSK Agreements                
Related Party Transaction [Line Items]                
Research and development expense   $ 4,500,000   $ 12,500,000        
Potential milestone payments payable     $ 33,000,000.0       $ 33,000,000.0  
License Agreement | QIMR Berghofer                
Related Party Transaction [Line Items]                
Research and development expense $ 3,000,000.0         $ 3,300,000