v3.10.0.1
Document and Entity Information - shares
6 Months Ended
Jul. 31, 2018
Aug. 31, 2018
Entity Information [Line Items]    
Document Type 10-Q  
Document Period End Date Jul. 31, 2018  
Amendment Flag false  
Entity Registrant Name Okta, Inc.  
Entity Central Index Key 0001660134  
Current Fiscal Year End Date --01-31  
Entity Filer Category Non-accelerated Filer  
Document Fiscal Year Focus 2019  
Document Period Focus Q2  
Class A Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   97,147,059
Class B Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   12,035,911