Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Detail)

v3.10.0.1
Subsequent Events - Additional Information (Detail) - USD ($)
$ in Millions
 9 Months Ended
Nov. 13, 2018
Jul. 17, 2018
Sep. 30, 2018
Subsequent Event [Line Items]      
Proceeds from warrants issued in connection with Preferred Stock exercised for cash   $ 13.8  
Warrant [Member]      
Subsequent Event [Line Items]      
Proceeds from warrants issued in connection with Preferred Stock exercised for cash     $ 6.5
Series D Preferred Stock [Member]      
Subsequent Event [Line Items]      
Number of common shares issued upon conversion of Preferred Stock   9,364,000  
Proceeds from warrants issued in connection with Preferred Stock exercised for cash     $ 5.0
Convertible into shares of common stock     7,868,000
Series D Preferred Stock [Member] | Subsequent Event [Member]      
Subsequent Event [Line Items]      
Number of common shares issued upon conversion of Preferred Stock 1,496,000    
Class of warrants exercised 9,505,500    
Convertible into shares of common stock 1,496,000    
Series D Preferred Stock [Member] | Subsequent Event [Member] | Warrant [Member]      
Subsequent Event [Line Items]      
Proceeds from warrants issued in connection with Preferred Stock exercised for cash $ 9.5