<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>373</ContextCount>
  <ElementCount>364</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>90</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - Condensed Consolidated Balance Sheet</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CondensedConsolidatedBalanceSheet</Role>
      <ShortName>Condensed Consolidated Balance Sheet</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - Condensed Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CondensedConsolidatedStatementsofOperations</Role>
      <ShortName>Condensed Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - Condensed Consolidated Statements of Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CondensedConsolidatedStatementsofComprehensiveLoss</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive Loss</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - Condensed Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CondensedConsolidatedStatementsofCashFlows</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1006007 - Statement - Condensed Consolidated Statements of Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CondensedConsolidatedStatementsofStockholdersEquity</Role>
      <ShortName>Condensed Consolidated Statements of Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - Description of Business and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DescriptionofBusinessandSummaryofSignificantAccountingPolicies</Role>
      <ShortName>Description of Business and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2103102 - Disclosure - Revenue</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/Revenue</Role>
      <ShortName>Revenue</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2108103 - Disclosure - Fair Value of Assets and Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/FairValueofAssetsandLiabilities</Role>
      <ShortName>Fair Value of Assets and Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2111104 - Disclosure - Cash Equivalents and Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CashEquivalentsandMarketableSecurities</Role>
      <ShortName>Cash Equivalents and Marketable Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2114105 - Disclosure - Derivative Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstruments</Role>
      <ShortName>Derivative Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2120106 - Disclosure - Business Combinations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BusinessCombinations</Role>
      <ShortName>Business Combinations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2125107 - Disclosure - Goodwill And Intangible Assets, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/GoodwillAndIntangibleAssetsNet</Role>
      <ShortName>Goodwill And Intangible Assets, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2130108 - Disclosure - Balance Sheet Components</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponents</Role>
      <ShortName>Balance Sheet Components</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2136109 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2138110 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2140111 - Disclosure - Equity Incentive Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlans</Role>
      <ShortName>Equity Incentive Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2148112 - Disclosure - Net Loss Per Share Attributable to Common Stockholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/NetLossPerShareAttributabletoCommonStockholders</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2151113 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Description of Business and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DescriptionofBusinessandSummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Description of Business and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.medallia.com/role/DescriptionofBusinessandSummaryofSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Revenue (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/RevenueTables</Role>
      <ShortName>Revenue (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/Revenue</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2309302 - Disclosure - Fair Value of Assets and Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/FairValueofAssetsandLiabilitiesTables</Role>
      <ShortName>Fair Value of Assets and Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/FairValueofAssetsandLiabilities</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2312303 - Disclosure - Cash Equivalents and Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CashEquivalentsandMarketableSecuritiesTables</Role>
      <ShortName>Cash Equivalents and Marketable Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/CashEquivalentsandMarketableSecurities</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2315304 - Disclosure - Derivative Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstrumentsTables</Role>
      <ShortName>Derivative Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/DerivativeInstruments</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2321305 - Disclosure - Business Combinations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BusinessCombinationsTables</Role>
      <ShortName>Business Combinations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/BusinessCombinations</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2326306 - Disclosure - Goodwill And Intangible Assets, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/GoodwillAndIntangibleAssetsNetTables</Role>
      <ShortName>Goodwill And Intangible Assets, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/GoodwillAndIntangibleAssetsNet</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2331307 - Disclosure - Balance Sheet Components (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponentsTables</Role>
      <ShortName>Balance Sheet Components (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/BalanceSheetComponents</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2341308 - Disclosure - Equity Incentive Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansTables</Role>
      <ShortName>Equity Incentive Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/EquityIncentivePlans</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2349309 - Disclosure - Net Loss Per Share Attributable to Common Stockholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/NetLossPerShareAttributabletoCommonStockholdersTables</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.medallia.com/role/NetLossPerShareAttributabletoCommonStockholders</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2405401 - Disclosure - Revenue - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/RevenueAdditionalInformationDetails</Role>
      <ShortName>Revenue - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Revenue - Performance Obligation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/RevenuePerformanceObligationDetails</Role>
      <ShortName>Revenue - Performance Obligation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Revenue - Summary of Revenue by Geographic Area (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/RevenueSummaryofRevenuebyGeographicAreaDetails</Role>
      <ShortName>Revenue - Summary of Revenue by Geographic Area (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Fair Value of Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/FairValueofAssetsandLiabilitiesDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.medallia.com/role/FairValueofAssetsandLiabilitiesTables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2413405 - Disclosure - Cash Equivalents and Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CashEquivalentsandMarketableSecuritiesDetails</Role>
      <ShortName>Cash Equivalents and Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.medallia.com/role/CashEquivalentsandMarketableSecuritiesTables</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2416406 - Disclosure - Derivative Instruments - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstrumentsAdditionalInformationDetails</Role>
      <ShortName>Derivative Instruments - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2417407 - Disclosure - Derivative Instruments - Fair Values of Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstrumentsFairValuesofInstrumentsDetails</Role>
      <ShortName>Derivative Instruments - Fair Values of Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2418408 - Disclosure - Derivative Instruments - Gains and Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstrumentsGainsandLossesDetails</Role>
      <ShortName>Derivative Instruments - Gains and Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2419409 - Disclosure - Derivative Instruments - Offsetting Arrangements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/DerivativeInstrumentsOffsettingArrangementsDetails</Role>
      <ShortName>Derivative Instruments - Offsetting Arrangements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2422410 - Disclosure - Business Combinations - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BusinessCombinationsAdditionalInformationDetails</Role>
      <ShortName>Business Combinations - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2423411 - Disclosure - Business Combinations - Schedule of Acquisition Consideration and Related Fair Values of Assets Acquired and Liabilities Assumed (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BusinessCombinationsScheduleofAcquisitionConsiderationandRelatedFairValuesofAssetsAcquiredandLiabilitiesAssumedDetails</Role>
      <ShortName>Business Combinations - Schedule of Acquisition Consideration and Related Fair Values of Assets Acquired and Liabilities Assumed (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2424412 - Disclosure - Business Combinations - Component of Identifiable Intangible Assets Acquired in Connection with Acquisitions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BusinessCombinationsComponentofIdentifiableIntangibleAssetsAcquiredinConnectionwithAcquisitionsDetails</Role>
      <ShortName>Business Combinations - Component of Identifiable Intangible Assets Acquired in Connection with Acquisitions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2427413 - Disclosure - Goodwill and Intangible Assets, Net - Changes in Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/GoodwillandIntangibleAssetsNetChangesinGoodwillDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Changes in Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2428414 - Disclosure - Goodwill and Intangible Assets, Net - Schedule Intangible Assets, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/GoodwillandIntangibleAssetsNetScheduleIntangibleAssetsNetDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Schedule Intangible Assets, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2429415 - Disclosure - Goodwill and Intangible Assets, Net - Future Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/GoodwillandIntangibleAssetsNetFutureAmortizationExpenseDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net - Future Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2432416 - Disclosure - Balance Sheet Components - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponentsAdditionalInformationDetails</Role>
      <ShortName>Balance Sheet Components - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2433417 - Disclosure - Balance Sheet Components - Summary of Property and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponentsSummaryofPropertyandEquipmentDetails</Role>
      <ShortName>Balance Sheet Components - Summary of Property and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2434418 - Disclosure - Balance Sheet Components - Accrued Expenses and Other Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponentsAccruedExpensesandOtherLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Components - Accrued Expenses and Other Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2435419 - Disclosure - Balance Sheet Components - Summary of Accrued Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/BalanceSheetComponentsSummaryofAccruedCompensationDetails</Role>
      <ShortName>Balance Sheet Components - Summary of Accrued Compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2437420 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/CommitmentsandContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2439421 - Disclosure - Income Taxes - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/IncomeTaxesNarrativeDetails</Role>
      <ShortName>Income Taxes - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2442422 - Disclosure - Equity Incentive Plans - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansAdditionalInformationDetails</Role>
      <ShortName>Equity Incentive Plans - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2443423 - Disclosure - Equity Incentive Plans - Schedule of 2019 Plan Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansScheduleof2019PlanActivityDetails</Role>
      <ShortName>Equity Incentive Plans - Schedule of 2019 Plan Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2444424 - Disclosure - Equity Incentive Plans - Stock-Based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansStockBasedCompensationExpenseDetails</Role>
      <ShortName>Equity Incentive Plans - Stock-Based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2445425 - Disclosure - Equity Incentive Plans - Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansStockOptionActivityDetails</Role>
      <ShortName>Equity Incentive Plans - Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2446426 - Disclosure - Equity Incentive Plans - Restricted Stock Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansRestrictedStockActivityDetails</Role>
      <ShortName>Equity Incentive Plans - Restricted Stock Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2447427 - Disclosure - Equity Incentive Plans - Valuation Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/EquityIncentivePlansValuationAssumptionsDetails</Role>
      <ShortName>Equity Incentive Plans - Valuation Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2450428 - Disclosure - Net Loss Per Share Attributable to Common Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/NetLossPerShareAttributabletoCommonStockholdersDetails</Role>
      <ShortName>Net Loss Per Share Attributable to Common Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.medallia.com/role/NetLossPerShareAttributabletoCommonStockholdersTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="mdla-20200731.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2452429 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.medallia.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.medallia.com/role/SubsequentEvents</ParentRole>
      <Position>59</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="mdla-20200731.htm">mdla-20200731.htm</File>
    <File>exhibit101creditagreem.htm</File>
    <File>exhibit21stellaagreeme.htm</File>
    <File>exhibit311-q27312020.htm</File>
    <File>exhibit312-q27312020.htm</File>
    <File>exhibit321-q27312020.htm</File>
    <File>exhibit322-q27312020.htm</File>
    <File>mdla-20200731.xsd</File>
    <File>mdla-20200731_cal.xml</File>
    <File>mdla-20200731_def.xml</File>
    <File>mdla-20200731_lab.xml</File>
    <File>mdla-20200731_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2017-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
