<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.24.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>217</ContextCount>
  <ElementCount>277</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>56</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>8</UnitCount>
  <MyReports>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Cover</Role>
      <ShortName>Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>Consolidated Balance Sheets (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Balance Sheets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Statements of Operations (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedStatementsofOperationsUnaudited</Role>
      <ShortName>Consolidated Statements of Operations (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedStatementsofComprehensiveIncomeUnaudited</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - Consolidated Statements of Stockholders' Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedStatementsofStockholdersEquityUnaudited</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/ConsolidatedStatementsofCashFlowsUnaudited</Role>
      <ShortName>Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Organization and Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPolicies</Role>
      <ShortName>Organization and Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Development and Other Agreements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DevelopmentandOtherAgreements</Role>
      <ShortName>Development and Other Agreements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Balance Sheet Details and Other Financial Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformation</Role>
      <ShortName>Balance Sheet Details and Other Financial Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Contingencies</Role>
      <ShortName>Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/StockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Business Segment and Geographic Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BusinessSegmentandGeographicInformation</Role>
      <ShortName>Business Segment and Geographic Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9954471 - Disclosure - Organization and Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Organization and Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/OrganizationandSignificantAccountingPolicies</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9954472 - Disclosure - Organization and Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesTables</Role>
      <ShortName>Organization and Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/OrganizationandSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9954473 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/FairValueMeasurements</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9954474 - Disclosure - Balance Sheet Details and Other Financial Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationTables</Role>
      <ShortName>Balance Sheet Details and Other Financial Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformation</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9954475 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/Debt</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9954476 - Disclosure - Stockholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/StockholdersEquityTables</Role>
      <ShortName>Stockholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/StockholdersEquity</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9954477 - Disclosure - Business Segment and Geographic Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BusinessSegmentandGeographicInformationTables</Role>
      <ShortName>Business Segment and Geographic Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/BusinessSegmentandGeographicInformation</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9954478 - Disclosure - Organization and Significant Accounting Policies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Organization and Significant Accounting Policies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesTables</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9954479 - Disclosure - Organization and Significant Accounting Policies - Earnings Per Share, Basic and Diluted (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesEarningsPerShareBasicandDilutedDetails</Role>
      <ShortName>Organization and Significant Accounting Policies - Earnings Per Share, Basic and Diluted (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9954480 - Disclosure - Organization and Significant Accounting Policies - Anti-dilutive Securities Excluded from Calculation of Net Income (Loss) per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesAntidilutiveSecuritiesExcludedfromCalculationofNetIncomeLossperShareDetails</Role>
      <ShortName>Organization and Significant Accounting Policies - Anti-dilutive Securities Excluded from Calculation of Net Income (Loss) per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9954481 - Disclosure - Development and Other Agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DevelopmentandOtherAgreementsDetails</Role>
      <ShortName>Development and Other Agreements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/DevelopmentandOtherAgreements</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9954482 - Disclosure - Fair Value Measurements - Fair Value Hierarchy for Financial Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/FairValueMeasurementsFairValueHierarchyforFinancialAssetsDetails</Role>
      <ShortName>Fair Value Measurements - Fair Value Hierarchy for Financial Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9954483 - Disclosure - Fair Value Measurements - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/FairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Fair Value Measurements - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9954484 - Disclosure - Fair Value Measurements - Estimated Fair Values of Debt Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/FairValueMeasurementsEstimatedFairValuesofDebtInstrumentsDetails</Role>
      <ShortName>Fair Value Measurements - Estimated Fair Values of Debt Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9954485 - Disclosure - Balance Sheet Details and Other Financial Information - Short-Term Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationShortTermMarketableSecuritiesDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Short-Term Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9954486 - Disclosure - Balance Sheet Details and Other Financial Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationNarrativeDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationTables</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9954487 - Disclosure - Balance Sheet Details and Other Financial Information - Inventory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationInventoryDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Inventory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9954488 - Disclosure - Balance Sheet Details and Other Financial Information - Prepaid and Other Current Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationPrepaidandOtherCurrentAssetsDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Prepaid and Other Current Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9954489 - Disclosure - Balance Sheet Details and Other Financial Information - Property and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationPropertyandEquipmentDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Property and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9954490 - Disclosure - Balance Sheet Details and Other Financial Information - Other Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherAssetsDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Other Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9954491 - Disclosure - Balance Sheet Details and Other Financial Information - Accounts Payable and Accrued Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationAccountsPayableandAccruedLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Accounts Payable and Accrued Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9954492 - Disclosure - Balance Sheet Details and Other Financial Information - Accrued Payroll and Related Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationAccruedPayrollandRelatedExpensesDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Accrued Payroll and Related Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9954493 - Disclosure - Balance Sheet Details and Other Financial Information - Other Long-Term Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherLongTermLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Other Long-Term Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9954494 - Disclosure - Balance Sheet Details and Other Financial Information - Other Income (Expense), Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherIncomeExpenseNetDetails</Role>
      <ShortName>Balance Sheet Details and Other Financial Information - Other Income (Expense), Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9954495 - Disclosure - Debt - Carrying Values and Estimated Fair Values of Debt Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DebtCarryingValuesandEstimatedFairValuesofDebtInstrumentsDetails</Role>
      <ShortName>Debt - Carrying Values and Estimated Fair Values of Debt Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9954496 - Disclosure - Debt - Conversion Value of Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.dexcom.com/role/DebtConversionValueofConvertibleNotesDetails</Role>
      <ShortName>Debt - Conversion Value of Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9954497 - Disclosure - Debt - Components of Interest Expense and Effective Interest Rates of Senior Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.dexcom.com/role/DebtComponentsofInterestExpenseandEffectiveInterestRatesofSeniorConvertibleNotesDetails</Role>
      <ShortName>Debt - Components of Interest Expense and Effective Interest Rates of Senior Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9954498 - Disclosure - Debt - Schedule of Key Details of Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.dexcom.com/role/DebtScheduleofKeyDetailsofConvertibleNotesDetails</Role>
      <ShortName>Debt - Schedule of Key Details of Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9954499 - Disclosure - Debt - 2023 Note Hedge (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Debt2023NoteHedgeDetails</Role>
      <ShortName>Debt - 2023 Note Hedge (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9954500 - Disclosure - Debt - 2023 Warrants (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Debt2023WarrantsDetails</Role>
      <ShortName>Debt - 2023 Warrants (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9954501 - Disclosure - Debt - 2028 Capped Call Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/Debt2028CappedCallTransactionsDetails</Role>
      <ShortName>Debt - 2028 Capped Call Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9954502 - Disclosure - Debt - Conversion Activity for Senior Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.dexcom.com/role/DebtConversionActivityforSeniorConvertibleNotesDetails</Role>
      <ShortName>Debt - Conversion Activity for Senior Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9954503 - Disclosure - Debt - Conversion Rights for Seniors Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.dexcom.com/role/DebtConversionRightsforSeniorsConvertibleNotesDetails</Role>
      <ShortName>Debt - Conversion Rights for Seniors Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9954504 - Disclosure - Debt - Revolving Credit Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DebtRevolvingCreditAgreementDetails</Role>
      <ShortName>Debt - Revolving Credit Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9954505 - Disclosure - Debt - Availability and Outstanding Borrowings under Credit Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/DebtAvailabilityandOutstandingBorrowingsunderCreditAgreementDetails</Role>
      <ShortName>Debt - Availability and Outstanding Borrowings under Credit Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9954506 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/IncomeTaxes</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9954507 - Disclosure - Stockholders' Equity - Share-Based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/StockholdersEquityShareBasedCompensationExpenseDetails</Role>
      <ShortName>Stockholders' Equity - Share-Based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9954508 - Disclosure - Stockholders' Equity - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/StockholdersEquityNarrativeDetails</Role>
      <ShortName>Stockholders' Equity - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9954509 - Disclosure - Business Segment and Geographic Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BusinessSegmentandGeographicInformationNarrativeDetails</Role>
      <ShortName>Business Segment and Geographic Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9954510 - Disclosure - Business Segment and Geographic Information - Schedule of Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/BusinessSegmentandGeographicInformationScheduleofRevenueDetails</Role>
      <ShortName>Business Segment and Geographic Information - Schedule of Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="dxcm-20240630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9954511 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.dexcom.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.dexcom.com/role/SubsequentEvents</ParentRole>
      <Position>60</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" isDefinitelyFs="true" isUsgaap="true" original="dxcm-20240630.htm">dxcm-20240630.htm</File>
    <File>dxcm-20240630.xsd</File>
    <File>dxcm-20240630_cal.xml</File>
    <File>dxcm-20240630_def.xml</File>
    <File>dxcm-20240630_lab.xml</File>
    <File>dxcm-20240630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>dxcm-20240630_g1.jpg</File>
    <File>dxcm-20240630_g2.jpg</File>
    <File>dxcm-20240630_g3.jpg</File>
    <File>dxcm-20240630_g4.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2024</BaseTaxonomy>
    <BaseTaxonomy items="735">http://fasb.org/us-gaap/2024</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2024</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2024</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
