Quarterly report pursuant to Section 13 or 15(d)

Collaboration and License Agreements - Additional Information (Detail)

v3.19.3
Collaboration and License Agreements - Additional Information (Detail) - USD ($)
1 Months Ended 9 Months Ended
Dec. 05, 2018
Feb. 15, 2017
Sep. 30, 2019
Dec. 31, 2016
Sep. 30, 2019
Dec. 31, 2020
Jul. 05, 2017
Novartis [Member] | Convertible Promissory Note [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Debt instrument, interest rate   6.00%          
Debt instrument, maturity date   Dec. 31, 2019          
Debt instrument, conversion price percentage   120.00%          
Promissory note, principal amount   $ 15,000,000          
Conversion of convertible note payable $ 15,000,000            
Conversion of convertible note payable to common stock 2,882,519            
Conversion price $ 5.77            
Collaboration Agreement [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Deferred revenue recognize period         1 year    
Deferred cost recognize period         1 year    
Collaboration Agreement [Member] | Novartis [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Non-refundable payment received       $ 50,000,000      
Proceeds from option exercised             $ 7,000,000
Collaboration and license agreement termination period         Sep. 30, 2019    
Maximum milestone payments to be received upon achievement of certain milestones       $ 650,000,000      
Percentage of observational study costs       50.00%      
Assumed percentage of observational study costs upon completion of ongoing Phase 2b trails       100.00%      
Amount of contract modification recognized on cumulative catch-up basis     $ 100,000        
Collaboration Agreement [Member] | Novartis [Member] | Scenario Forecast [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Future milestone payments           $ 150,000,000  
Investment Agreement [Member] | Novartis [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Debt instrument, maximum borrowing capacity       $ 15,000,000      
Debt instrument, interest rate       6.00%      
Debt instrument, maturity date       Dec. 31, 2019      
Investment Agreement [Member] | Novartis [Member] | Convertible Promissory Note [Member]              
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]              
Debt instrument, conversion price percentage   120.00%          
Number of days trailing average closing price of common stock immediately prior to the conversion date   20 days          
Promissory note, principal amount   $ 15,000,000          
Conversion of convertible note payable $ 15,000,000            
Conversion of convertible note payable to common stock 2,882,519            
Conversion price $ 5.77