XML 15 R1.htm IDEA: XBRL DOCUMENT v3.3.1.900
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Jan. 31, 2016
Feb. 29, 2016
Jul. 31, 2015
Document And Entity Information [Line Items]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Jan. 31, 2016    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY    
Trading Symbol BOX    
Entity Registrant Name BOX INC    
Entity Central Index Key 0001372612    
Current Fiscal Year End Date --01-31    
Entity Filer Category Large Accelerated Filer    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 986
Class A Common Stock      
Document And Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   42.4  
Class B Common Stock      
Document And Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   82.0