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Warrants - Additional Information (Detail) - USD ($)
Feb. 08, 2019
Jun. 09, 2017
Sep. 30, 2019
Dec. 31, 2018
June 2017 Warrants [Member]        
Class Of Warrant Or Right [Line Items]        
Warrants are fully vested, exercise price   $ 8.25    
Fair value of the warrants derivative liability     $ 300 $ 3,700
June 2017 Warrants [Member] | IPO Selling Agent [Member]        
Class Of Warrant Or Right [Line Items]        
Purchase of warrants issued   33,275    
June 2017 Warrants [Member] | IPO [Member]        
Class Of Warrant Or Right [Line Items]        
Warrants years of life   5 years    
February 2019 Warrants [Member]        
Class Of Warrant Or Right [Line Items]        
Warrants are fully vested, exercise price $ 1.75      
Fair value of the warrants derivative liability $ 196,000   $ 43,600  
February 2019 Warrants [Member] | IPO Selling Agent [Member]        
Class Of Warrant Or Right [Line Items]        
Purchase of warrants issued 363,400      
February 2019 Warrants [Member] | IPO [Member]        
Class Of Warrant Or Right [Line Items]        
Warrants years of life 4 years