Quarterly report pursuant to Section 13 or 15(d)

Merger with Private Molecular - Additional Information (Detail)

v3.8.0.1
Merger with Private Molecular - Additional Information (Detail)
2 Months Ended 3 Months Ended 9 Months Ended
Aug. 01, 2017
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
$ / shares
Sep. 30, 2016
USD ($)
Jun. 01, 2017
USD ($)
Mar. 24, 2017
USD ($)
Business Acquisition [Line Items]                
Reverse stock split of common stock, description         11-for-1 reverse stock split      
Reverse stock split of common stock conversion ratio 11              
Exercise price per share on stock options after reverse stock split | $ / shares         $ 6.40      
Stock compensation     $ 1,378,000 $ 27,000 $ 1,430,000 $ 85,000    
Operating expenses     6,518,000 3,081,000 13,062,000 9,731,000    
2014 Equity Incentive Plan                
Business Acquisition [Line Items]                
Stock compensation         $ 1,200,000      
Threshold                
Business Acquisition [Line Items]                
Reverse stock split of common stock, description         11-for-1 reverse stock split      
Reverse stock split of common stock conversion ratio 11              
Common stock shares issued in exchange of each share | shares 7.7844              
Threshold equity holders ownership interest 34.40%              
Private Molecular equity holders ownership interest 65.60%              
Stock option outstanding to purchase common stock | shares 963,681              
Number of vested stock option shares after reverse stock split | shares 963,681              
Exercise price per share on stock options after reverse stock split | $ / shares $ 33.62              
Fair value inputs discount rate 12.00%              
Transaction costs associated with Merger $ 1,900,000              
Principal amount             $ 2,000,000 $ 2,000,000
Promissory note interest rate               1.00%
Operating expenses   $ 142,000            
Threshold | Eliminations                
Business Acquisition [Line Items]                
Transaction costs associated with Merger   $ 3,300,000 $ 3,300,000 $ 0 $ 3,300,000 0    
Loss on conversion of notes         4,700,000 0    
Stock-based compensation expense         1,200,000 0    
Interest expense         300,000 0    
Change in fair value of warrants liability         $ 300,000 $ 500,000