Quarterly report pursuant to Section 13 or 15(d)

Collaboration and License Agreements - Additional Information (Detail)

v3.19.2
Collaboration and License Agreements - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended
Dec. 05, 2018
Feb. 15, 2017
Dec. 31, 2016
Jun. 30, 2019
Jun. 30, 2019
Jul. 05, 2017
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]            
Cumulative catch-up adjustment in revenue       $ 4,600,000    
Cumulative catch-up adjustment in operating expenses       $ 100,000    
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
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%      
Required prior written notice period for termination of collaboration agreement     180 days      
Percentage of reduction in milestone and royalty payments     50.00%      
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