Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.3.0.814
Stockholders' Equity - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2015
Jun. 15, 2015
Jun. 10, 2015
May. 15, 2015
Nov. 03, 2015
Jun. 30, 2015
Sep. 30, 2015
Dec. 31, 2014
Aug. 07, 2015
Apr. 02, 2014
Subsidiary, Sale of Stock [Line Items]                    
Common stock shares issued 9,060,314           9,060,314 7,753,717    
Expended or accrued offering cost $ 200,507           $ 200,507 $ 248,731    
Follow-on Offering [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Common stock, shares issued           1,306,597        
Price per share           $ 11.40        
IPO [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Gross proceeds from issuance of common stock       $ 14,300,000            
Common stock, shares issued       1,250,000            
Price per share       $ 11.40            
Net proceeds after deducting offering expenses       $ 13,200,000            
Over-Allotment Option [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Gross proceeds from issuance of common stock   $ 645,000                
Net proceeds after deducting offering expenses   $ 606,000                
Additional common stock shares issued     56,597              
At-the-Market Program [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Sale of common stock sold under sale agreement 0                  
Expended or accrued offering cost $ 62,000           62,000      
Maximum [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Securities allowed for issuance                   $ 300,000,000
Maximum [Member] | At-the-Market Program [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Common stock, value authorized                 $ 30,000,000  
Common Stock [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Gross proceeds from issuance of common stock             $ 15,000,000      
Common stock, shares issued             1,306,597 1,223,453    
Common Stock [Member] | Universal Registration Statement [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Common stock shares issued 1,223,453           1,223,453      
Subsequent Event [Member] | At-the-Market Program [Member]                    
Subsidiary, Sale of Stock [Line Items]                    
Gross proceeds from issuance of common stock         $ 20,000          
Sale of common stock sold under sale agreement         2,100