Quarterly report pursuant to Section 13 or 15(d)

Note Payable - Additional Information (Detail)

Note Payable - Additional Information (Detail)
9 Months Ended
Feb. 15, 2017
USD ($)
Jan. 24, 2017
USD ($)
Sep. 30, 2017
USD ($)
Dec. 19, 2016
USD ($)
Jul. 31, 2010
USD ($)
Debt Instrument [Line Items]          
Convertible note payable     $ 13,000,000    
Novartis [Member] | Investment Agreement [Member]          
Debt Instrument [Line Items]          
Deferred revenue       $ 2,500,000  
Novartis [Member] | Investment Agreement [Member] | Maximum [Member]          
Debt Instrument [Line Items]          
Percentage of outstanding shares will receive upon debt instrument conversion     19.00%    
Promissory note [Member] | Pfizer Inc. [Member]          
Debt Instrument [Line Items]          
Note payable         $ 1,000,000
Debt instrument, interest rate     7.00%    
Debt instrument, maturity date     Jul. 29, 2020    
Prepayment of notes payable   $ 1,004,861      
Convertible Promissory Note [Member] | Novartis [Member]          
Debt Instrument [Line Items]          
Debt instrument, interest rate 6.00%        
Debt instrument, maturity date Dec. 31, 2019        
Promissory note, principal amount $ 15,000,000        
Promissory note conversion, description Novartis has the option to convert all or part of the Novartis Note into shares of the Company’s common stock upon a change in control of the Company or termination of the Collaboration Agreement by Novartis pursuant to certain provisions. If converted, the principal and accrued interest under the Novartis Note will convert into the Company’s common stock at a conversion price equal to 120% of the 20-day trailing average closing price per share of the common stock immediately prior to the conversion date. In the event the aggregate number of shares of common stock issued upon the conversion would exceed the lesser of 19.0% of the Company’s outstanding shares on a fully-diluted basis (i) at the inception of the Investment Agreement or (ii) on the conversion date, then only the lesser amount shall convert into shares of common stock and Novartis shall be repaid in cash for any remaining principal and unpaid interest after such conversion. Upon the occurrence of certain events of default, the Novartis Note requires the Company to repay the principal balance of the Novartis Note and any unpaid accrued interest.        
Principal and accrued interest of note to be converted into common stock at conversion price, in percentage 120.00%        
Trailing period for average closing price per share of common stock | d 20        
Proceeds from issuance of convertible note payable $ 15,000,000        
Convertible note payable 12,500,000        
Reduction of outstanding receivable $ 2,500,000        
Fair value of convertible note payable     $ 13,000,000