Annual report pursuant to Section 13 and 15(d)

Merger with Private Molecular - Additional Information (Detail)

v3.19.1
Merger with Private Molecular - Additional Information (Detail) - USD ($)
 5 Months Ended 12 Months Ended
Aug. 01, 2017
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Jun. 01, 2017
Mar. 24, 2017
Business Acquisition [Line Items]            
Exercise price per share on stock options after reverse stock split     $ 6.98 $ 8.30    
Operating expenses     $ 44,284,000 $ 21,242,000    
Loss on conversion of notes     $ 0 4,619,000    
2014 Equity Incentive Plan            
Business Acquisition [Line Items]            
Stock compensation expense related to the acceleration of pre merger options $ 1,200,000     1,200,000    
Share Based Awards            
Business Acquisition [Line Items]            
Options to purchase shares of common stock 963,681          
Threshold            
Business Acquisition [Line Items]            
Common stock shares issued in exchange of each share 7.7844          
Threshold equity holders ownership interest 34.40%          
Private Molecular equity holders ownership interest 65.60%          
Stock option outstanding to purchase common stock 963,681          
Exercise price per share on stock options after reverse stock split $ 33.62          
Transaction costs associated with Merger   $ 2,000,000   2,000,000    
Principal amount         $ 2,000,000 $ 2,000,000
Promissory note interest rate           1.00%
Operating expenses   320,000        
Threshold | Eliminations            
Business Acquisition [Line Items]            
Transaction costs associated with Merger   $ 5,400,000   5,400,000    
Loss on conversion of notes       4,600,000    
Stock-based compensation expense       1,200,000    
Severance costs       2,900,000    
Interest expense       300,000    
Interest expense       $ 100,000    
Threshold | Measurement Input, Discount Rate            
Business Acquisition [Line Items]            
Fair value inputs discount rate 12