Annual report pursuant to Section 13 and 15(d)

Notes Payable - Additional Information (Detail)

v3.20.1
Notes Payable - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Dec. 05, 2018
Feb. 15, 2017
Jan. 24, 2017
Dec. 31, 2016
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 19, 2016
Jul. 31, 2010
Debt Instrument [Line Items]                  
Proceeds from issuance of convertible note payable         $ 0 $ 0 $ 12,500,000    
Conversion of convertible note payable         $ 0 $ 13,729,000 $ 0    
Novartis [Member] | Investment Agreement [Member]                  
Debt Instrument [Line Items]                  
Debt instrument, interest rate       6.00%          
Debt instrument, maturity date       Dec. 31, 2019          
Deferred revenue               $ 2,500,000  
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         The terms of the Novartis Note allowed the Company to convert the principal and accrued interest 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.        
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   20 days              
Proceeds from issuance of convertible note payable   $ 15,000,000              
Convertible note payable   12,500,000              
Reduction of outstanding receivable   2,500,000              
Conversion of convertible note payable $ 15,000,000                
Conversion of convertible note payable to common stock 2,882,519                
Conversion price $ 5.77                
Fair value of convertible note payable         $ 12,500,000        
Convertible Promissory Note [Member] | Novartis [Member] | Investment Agreement [Member]                  
Debt Instrument [Line Items]                  
Promissory note, principal amount   $ 15,000,000              
Principal and accrued interest of note to be converted into common stock at conversion price, in percentage   120.00%              
Conversion of convertible note payable $ 15,000,000                
Conversion of convertible note payable to common stock 2,882,519                
Conversion price $ 5.77