Quarterly report pursuant to sections 13 or 15(d)

Stock-Based Compensation (Details)

v2.4.0.8
Stock-Based Compensation (Details) (USD $)
3 Months Ended
Oct. 31, 2013
Oct. 31, 2012
Stock-based compensation    
Expected volatility (as a percent) 83.62%  
Expected volatility, minimum (as a percent)   79.25%
Expected volatility, maximum (as a percent)   97.85%
Risk-free interest rate (as a percent) 0.69%  
Expected forfeiture rate (as a percent) 0.00% 0.00%
Expected term 3 years  
Stock-based compensation expense recognized $ 70,000 $ 180,000
Additional disclosures    
Weighted-average grant date fair value (in dollars per share) $ 0.14 $ 0.16
Minimum
   
Stock-based compensation    
Risk-free interest rate (as a percent)   0.36%
Expected term   3 years
Maximum
   
Stock-based compensation    
Risk-free interest rate (as a percent)   1.92%
Expected term   10 years
Research and development expense
   
Stock-based compensation    
Stock-based compensation expense recognized 8,000 20,000
General and administrative expense
   
Stock-based compensation    
Stock-based compensation expense recognized $ 62,000 $ 160,000
2011 Plan | Employees
   
Stock-based compensation    
Options granted to purchase shares   155,000
Term of stock options   10 years
Exercise price, low end of the range (in dollars per share)   $ 0.20
Exercise price, high end of the range (in dollars per share)   $ 0.42
2011 Plan | Employees | Minimum
   
Stock-based compensation    
Vesting period   2 years
2011 Plan | Employees | Maximum
   
Stock-based compensation    
Vesting period   3 years
2011 Plan | Consultant
   
Stock-based compensation    
Options granted to purchase shares 500,000 1,200,000
Term of stock options 3 years 3 years
Exercise price (in dollars per share) $ 0.26 $ 0.18