Annual report pursuant to Section 13 and 15(d)

Significant Inputs and Assumptions Used in Lattice for Derivative Liability (Detail)

v3.7.0.1
Significant Inputs and Assumptions Used in Lattice for Derivative Liability (Detail) - $ / shares
12 Months Ended
Sep. 15, 2016
Jun. 23, 2015
May 31, 2015
Apr. 30, 2015
Feb. 06, 2015
Sep. 26, 2014
May 31, 2017
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]              
Contractual conversion rate $ 0.78           $ 0.60
Adjusted conversion price       $ 0.675      
Contractual term to maturity (years) 5 years           4 years 3 months 15 days
Expected volatility 106.00%           94.00%
Risk-free rate 1.20%           1.71%
Derivative Liability              
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]              
Quoted market price on valuation date   $ 0.90 $ 0.99   $ 0.96 $ 0.79  
Contractual conversion rate   1.00 1.00   1.00 1.00  
Adjusted conversion price [1]   $ 0.6750 $ 0.6750   $ 1.0000 $ 0.9759  
Contractual term to maturity (years)   1 month 13 days     5 months 27 days 2 years  
Expected volatility   48.00%     124.00% 123.00%  
Contractual interest rate   1.20%     2.00% 5.00%  
Risk-free rate   0.001%     0.045% 0.59%  
Risk adjusted rate   2.80% 2.80%   2.78% 2.69%  
Probability of event of default   5.00% 5.00%   5.00% 5.00%  
Derivative Liability | Minimum              
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]              
Contractual term to maturity (years)     2 months 5 days        
Expected volatility     90.00%        
Contractual interest rate     1.50%        
Risk-free rate     0.041%        
Derivative Liability | Maximum              
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]              
Contractual term to maturity (years)     1 year 3 months 29 days        
Expected volatility     114.00%        
Contractual interest rate     5.00%        
Risk-free rate     0.48%        
[1] The adjusted conversion price input used in the Binomial Lattice Model considers both (i) the reduction of the conversion price to $0.675 on April 30, 2015, as result of a private placement offering in which Common Stock was sold for a weighted average price of $0.75 and (ii) potential adjustment to the stated conversion price due to a future dilutive issuance. This input was calculated using a probability-weighted approach which considered the likelihood of various scenarios occurring including (i) potential success or failure of various phases for PRO 140, (ii) the probability the Company will enter into a future financing and (iii) and the potential price of a future financing.