v3.20.1
Summary of business and significant accounting policies - Intangible Assets (Details)
12 Months Ended
Jan. 31, 2020
Computer Software And Capitalized Software Development Costs  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 3 years
Developed technology  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 3 years
Acquired HSA Intangible Assets  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 15 years
Minimum | 401(k) Customer Relationships  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 10 years
Minimum | Developed technology  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 2 years
Maximum | 401(k) Customer Relationships  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 15 years
Maximum | Developed technology  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life of intangible assets 5 years