Warrants - Additional Information (Detail) - $ / shares
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Jul. 31, 2014
Warrants for Preferred Stock [Member]        
Class of Warrant or Right [Line Items]        
Number of shares callable by warrants       236,836
Warrants for Common Stock Converted from Warrants for Preferred Stock [Member]        
Class of Warrant or Right [Line Items]        
Number of shares callable by warrants       89,708
Warrants for Common Stock Converted from Warrants for Preferred Stock [Member] | Weighted Average [Member]        
Class of Warrant or Right [Line Items]        
Weighted average exercise price to purchase common stock       $ 6.32
Warrants for Common Stock [Member]        
Class of Warrant or Right [Line Items]        
Number of shares callable by warrants 18,939      
Shares covered under warrants exercised 70,769      
Warrants for Common Stock [Member] | Weighted Average [Member]        
Class of Warrant or Right [Line Items]        
Weighted average exercise price to purchase common stock $ 7.92      
Common Stock [Member]        
Class of Warrant or Right [Line Items]        
Number of shares issued 3,200,000 5,750,000 100,378  
Warrant [Member] | Common Stock [Member]        
Class of Warrant or Right [Line Items]        
Number of shares issued 54,010