Revenue - Schedule of total revenue by geographic areas (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 130,329	$ 89,388
MongoDB Atlas-related
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	54,170	30,863
Other subscription
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	70,686	53,131
Services
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	5,473	5,394
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	81,538	57,756
Europe, Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	39,009	25,320
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 9,782	$ 6,312