Annual report pursuant to Section 13 and 15(d)

Subsequent Events - Additional Information (Detail)

v3.6.0.2
Subsequent Events - Additional Information (Detail) - USD ($)
 1 Months Ended 12 Months Ended
Feb. 02, 2017
Jan. 01, 2017
Jul. 27, 2015
Jan. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Nov. 07, 2014
Jul. 25, 2014
Subsequent Event [Line Items]                
Options to purchase common stock         114,436      
Registration statement, sale of common stock             $ 25,000,000  
Proceeds from sale of common stock     $ 21,100,000     $ 4,300,000    
Registration statement, event description         Entered into an at-the-market facility (ATM) to sell up to $25 million of common stock under the registration statement.      
Proceeds from sale of common stock     8,200,000   23,447,003 23,447,003    
Common sock offering price     $ 2.81         $ 5.50
Subsequent Event [Member]                
Subsequent Event [Line Items]                
Registration statement, sale of common stock       $ 124,100        
Proceeds from sale of common stock $ 9,200,000              
Registration statement, event description       The Company utilized its ATM facility to offer and sell 124,100 shares of common stock for net proceeds of $158,000 as permitted under the Company's shelf registration statement        
Proceeds from sale of common stock 5,200,000              
Common sock offering price $ 1.93              
Subsequent Event [Member] | At the Market Facility [Member]                
Subsequent Event [Line Items]                
Proceeds from sale of common stock       $ 158,000        
Subsequent Event [Member] | Employees And Consultants [Member]                
Subsequent Event [Line Items]                
Options to purchase common stock   1,016,301            
Subsequent Event [Member] | 2013 Equity Incentive Plan [Member]                
Subsequent Event [Line Items]                
Number of shares automatically increased in share reserves   1,172,350