Quarterly report pursuant to Section 13 or 15(d)

Organization and Description of Business - Additional Information (Detail)

v3.5.0.2
Organization and Description of Business - Additional Information (Detail) - USD ($)
 6 Months Ended
Jul. 27, 2016
Nov. 02, 2015
Jun. 12, 2015
Aug. 01, 2014
Jun. 30, 2016
Jun. 30, 2015
Dec. 31, 2015
Organization And Description Of Business [Line Items]              
Additional stock reserved for future issuance         18,169,370   17,816,862
Proceeds from exercise of warrants         $ 16,000 $ 86,913  
Net proceeds from initial public offering       $ 35,000,000      
Private Placement [Member]              
Organization And Description Of Business [Line Items]              
Number of securities received by investors     4,728,128        
Additional stock reserved for future issuance     2,364,066        
Warrant exercise price per share     $ 8.00   $ 4.65    
Net proceeds received     $ 18,300,000        
Warrants expiration date         Jun. 11, 2020    
Initial Public Offering [Member]              
Organization And Description Of Business [Line Items]              
Public offering price, per unit       $ 6.00      
Initial Public Offering [Member] | Subsequent Event [Member]              
Organization And Description Of Business [Line Items]              
Number of securities received by investors 14,000,000            
Additional stock reserved for future issuance 14,000,000            
Warrant exercise price per share $ 3            
Public offering price, per unit $ 2.5            
Net proceeds from initial public offering $ 32,600,000            
Class B Warrants [Member]              
Organization And Description Of Business [Line Items]              
Warrants exercised   4,812,328          
Common stock shares issued upon exercise of warrants   2,406,164          
Proceeds from exercise of warrants   $ 9,600,000          
Unexercised warrants terminated   2,068,005          
Warrants expiration date         Nov. 02, 2015    
Class B Warrants [Member] | Initial Public Offering [Member]              
Organization And Description Of Business [Line Items]              
Warrant exercise price per share       $ 4.00