Revenue - Schedule of total revenue by geographic areas (Details) - USD ($)
$ in Thousands
3 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue $ 89,388 $ 50,139
MongoDB Atlas-related    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue 30,863 6,963
Other subscription    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue 53,131 39,106
Services    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue 5,394 4,070
Americas    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue 57,756 33,420
Europe, Middle East and Africa    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue 25,320 14,024
Asia Pacific    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total revenue $ 6,312 $ 2,695