Stock-Based Compensation - Fair Value Assumptions, ESPP (Details) - 2015 Employee Stock Purchase Plan - $ / shares
6 Months Ended 8 Months Ended
Apr. 30, 2016
Oct. 30, 2015
Nov. 01, 2015
Mar. 05, 2015
Stock-Based compensation        
Risk-free interest rate   0.10%    
Expected term   7 months 2 days    
Expected volatility   61.00%    
Dividend yield   0.00%    
Fair market value of common stock (in usd per share)   $ 4.82 $ 4.89 $ 11.50
Fair value per share (in usd per share)   $ 3.84    
Forecast        
Stock-Based compensation        
Risk-free interest rate 0.27%      
Expected term 6 months      
Expected volatility 55.00%      
Dividend yield 0.00%      
Fair value per share (in usd per share) $ 1.49