| Document and Entity Information | Oct. 29, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 29, 2021 |
| Entity Registrant Name | Medallia, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-38982 |
| Entity Tax Identification Number | 77-0558353 |
| Entity Address, Address Line One | 575 Market Street |
| Entity Address, Address Line Two | Suite 1850 |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94105 |
| City Area Code | 605 |
| Local Phone Number | 321-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001540184 |
| Title of 12(b) Security | Common Stock (par value $0.001 per share) |
| Trading Symbol | MDLA |
| Security Exchange Name | NYSE |
