Geographic Information - Revenue by Location (Details) - USD ($)
$ in Thousands
3 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]    
Revenue $ 37,314 $ 25,020
United States    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Revenue 29,468 20,217
International    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Revenue $ 7,846 $ 4,803