Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Details)

v3.10.0.1
Related-Party Transactions - Additional Information (Details)
 3 Months Ended 9 Months Ended 84 Months Ended
Jul. 31, 2018
USD ($)
Jun. 30, 2018
USD ($)
May 31, 2018
USD ($)
shares
Aug. 30, 2010
USD ($)
Sep. 30, 2018
USD ($)
Director
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
Director
Sep. 30, 2017
USD ($)
Dec. 31, 2015
$ / shares
shares
Dec. 31, 2017
USD ($)
Related Party Transaction [Line Items]                    
Principal amount of promissory notes                   $ 208,000
Accounts receivable         $ 2,443,000   $ 2,443,000     $ 1,624,000
Remaining deliverables under license agreement             0      
Second Director Performing Consulting Services                    
Related Party Transaction [Line Items]                    
Payments for performed consulting services         5,000 $ 7,500 20,000 $ 22,500    
Options granted to purchase common stock | shares                 3,269  
Second Director Performing Consulting Services | Minimum                    
Related Party Transaction [Line Items]                    
Fair values of the common stock price per share                 4 years  
Third Director Performing Consulting Services                    
Related Party Transaction [Line Items]                    
Payments for performed consulting services         $ 5,000 7,500 $ 20,000 17,500    
Chief Executive Officer                    
Related Party Transaction [Line Items]                    
Principal amount of promissory notes       $ 200,000            
Promissory note, accrue interest rate percentage       0.53%            
Promissory note maturity date       Aug. 30, 2019            
Collaboration Agreements                    
Related Party Transaction [Line Items]                    
Related party transaction agreed to pay one time success fee   $ 400,000                
Merck Agreement                    
Related Party Transaction [Line Items]                    
Execution of directors fees paid $ 400,000                  
Celgene                    
Related Party Transaction [Line Items]                    
Equity interest percentage         10.50%   10.50%     15.40%
Number of directors performed consulting services | Director         3   3      
Celgene | First Director Performing Consulting Service                    
Related Party Transaction [Line Items]                    
Payments for performed consulting services         $ 10,000 $ 15,000 $ 40,000 45,000    
Options granted to purchase common stock | shares                 9,805  
Advisory fees             $ 0 $ 250,000    
Celgene | First Director Performing Consulting Service | Minimum                    
Related Party Transaction [Line Items]                    
Fair values of the common stock price per share | $ / shares                 $ 4.36  
Fair values of the common stock price per share                 4 years  
Celgene | First Director Performing Consulting Service | Maximum                    
Related Party Transaction [Line Items]                    
Fair values of the common stock price per share | $ / shares                 $ 11.98  
Merck Sharp & Dohme Corp                    
Related Party Transaction [Line Items]                    
Equity interest percentage         12.50%   12.50%     0.00%
SutroVax                    
Related Party Transaction [Line Items]                    
Accounts receivable         $ 584,000   $ 584,000     $ 34,000
Percentage common stock ownership interest         5.60%   5.60%     7.80%
Carrying value of common stock under the cost method             $ 0      
Number of warrants to purchase | shares     100,000              
Value of warrant to purchase of preferred stock     $ 140,000