Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v3.3.1.900
Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2016
Jan. 31, 2015
Stock-based compensation        
Expected volatility, minimum (as a percent) 88.31% 90.35% 83.57% 88.82%
Expected volatility, maximum (as a percent) 88.37% 91.86% 89.70% 93.11%
Risk-free interest rate, minimum (as a percent) 1.58% 1.31% 0.86% 0.36%
Risk-free interest rate, maximum (as a percent) 2.01% 1.94% 2.01% 2.13%
Expected forfeiture rate (as a percent) 0.00% 0.00% 0.00% 0.00%
Stock-based compensation expense recognized $ 1.5 $ 0.4 $ 3.0 $ 1.0
Weighted-average grant date fair value (in dollars per share) $ 2.81 $ 4.14 $ 6.40 $ 4.60
Minimum        
Stock-based compensation        
Expected term 5 years 5 years 2 years 7 months 6 days 2 years
Maximum        
Stock-based compensation        
Expected term 6 years 6 months 6 years 6 months 6 years 6 months 6 years 6 months
Research and development expense.        
Stock-based compensation        
Stock-based compensation expense recognized $ 0.2 $ 0.2 $ 0.5 $ 0.5
General and administrative expenses.        
Stock-based compensation        
Stock-based compensation expense recognized $ 1.3 $ 0.2 $ 2.5 $ 0.5
2011 Plan        
Stock-based compensation        
Options granted to purchase shares     2,052,250  
2011 Plan | Employees        
Stock-based compensation        
Options granted to purchase shares 8,750 21,250 1,366,250 128,750
Term of stock options 10 years 10 years   10 years
Vesting period 3 years 3 years    
Exercise price, low end of the range (in dollars per share) $ 3.44 $ 7.80   $ 8.20
Exercise price, high end of the range (in dollars per share) $ 4.29 $ 10.60   $ 10.60
2011 Plan | Employees | Minimum        
Stock-based compensation        
Vesting period       1 year
2011 Plan | Employees | Maximum        
Stock-based compensation        
Vesting period       3 years
2011 Plan | Directors        
Stock-based compensation        
Options granted to purchase shares     618,000  
2011 Plan | Consultants        
Stock-based compensation        
Options granted to purchase shares     68,000 25,000
Term of stock options     3 years  
Exercise price, low end of the range (in dollars per share)       $ 7.80
Exercise price, high end of the range (in dollars per share)     $ 5.76 $ 8.60
2011 Plan | Consultants | Minimum        
Stock-based compensation        
Term of stock options       1 year
2011 Plan | Consultants | Maximum        
Stock-based compensation        
Term of stock options       3 years
2011 Plan | Employees and directors        
Stock-based compensation        
Term of stock options     10 years  
Exercise price, low end of the range (in dollars per share)     $ 3.44  
Exercise price, high end of the range (in dollars per share)     $ 6.21  
2011 Plan | Employees and directors | Minimum        
Stock-based compensation        
Vesting period     1 year  
2011 Plan | Employees and directors | Maximum        
Stock-based compensation        
Vesting period     3 years