Quarterly report pursuant to Section 13 or 15(d)

Fair Value of Warrants - Assumptions Used in Computing Fair Value of Derivative Warrants (Detail)

v3.5.0.2
Fair Value of Warrants - Assumptions Used in Computing Fair Value of Derivative Warrants (Detail) - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2016
Dec. 31, 2015
Sep. 30, 2016
Sep. 30, 2016
Financial        
Class of Warrant or Right [Line Items]        
Exercise price (in dollars per share)   $ 4.00    
Expected life (years)   2 months 23 days    
Expected volatility   70.82%    
Risk-free interest rate   0.16%    
Expected dividend yield   0.00%    
2016 Offering        
Class of Warrant or Right [Line Items]        
Exercise price (in dollars per share) $ 2.25   $ 2.25 $ 2.25
Expected life (years) 5 years 3 months 22 days   5 years 6 months 5 years 6 months
Expected volatility 72.97%   73.28% 74.36%
Risk-free interest rate 1.14%   1.21% 1.30%
Expected dividend yield 0.00%   0.00% 0.00%