STOCKHOLDERS’ EQUITY (Details)
Jan. 31, 2017
vote
class
$ / shares
shares
Sep. 30, 2016
vote
class
Class of Stock [Line Items]    
Preferred stock, shares authorized (in shares) 200,000,000  
Preferred stock, par value (in dollars per share) | $ / shares $ 0.000025  
Preferred stock, shares issued (in shares) 0  
Preferred stock, shares outstanding (in shares) 0  
Common stock, number of classes of stock | class 2 2
Common stock, par value (in dollars per share) | $ / shares $ 0.000025  
Common Class A    
Class of Stock [Line Items]    
Common stock, shares authorized (in shares) 1,000,000,000  
Common stock, shares issued (in shares) 33,500,377  
Common stock number of votes per share | vote 1 1
Common Class B    
Class of Stock [Line Items]    
Common stock, shares authorized (in shares) 200,000,000  
Common stock, shares issued (in shares) 109,713,179  
Common stock number of votes per share | vote 10 10