<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>210</ContextCount>
  <ElementCount>268</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>65</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSS</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS??? EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS??? EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Organization, Business, and Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/OrganizationBusinessandBasisofPresentation</Role>
      <ShortName>Organization, Business, and Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Liquidity and Uncertainties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LiquidityandUncertainties</Role>
      <ShortName>Liquidity and Uncertainties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Product Revenue, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/ProductRevenueNet</Role>
      <ShortName>Product Revenue, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Cash, Cash Equivalents, Restricted Cash and Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecurities</Role>
      <ShortName>Cash, Cash Equivalents, Restricted Cash and Marketable Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Inventory</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/Inventory</Role>
      <ShortName>Inventory</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Accrued Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/AccruedLiabilities</Role>
      <ShortName>Accrued Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Long Term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LongTermDebt</Role>
      <ShortName>Long Term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Stock-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensation</Role>
      <ShortName>Stock-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.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>21</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.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>22</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - Product Revenue, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/ProductRevenueNetTables</Role>
      <ShortName>Product Revenue, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/ProductRevenueNet</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Cash, Cash Equivalents, Restricted Cash and Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecuritiesTables</Role>
      <ShortName>Cash, Cash Equivalents, Restricted Cash and Marketable Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecurities</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Inventory (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/InventoryTables</Role>
      <ShortName>Inventory (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/Inventory</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Accrued Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/AccruedLiabilitiesTables</Role>
      <ShortName>Accrued Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/AccruedLiabilities</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Long Term Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LongTermDebtTables</Role>
      <ShortName>Long Term Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/LongTermDebt</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Stock-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationTables</Role>
      <ShortName>Stock-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/StockbasedCompensation</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/SegmentInformation</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - Summary of Significant Accounting Policies - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPoliciesIncomeTaxesDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Summary of Significant Accounting Policies - Schedule of Basic and Diluted Loss Per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SummaryofSignificantAccountingPoliciesScheduleofBasicandDilutedLossPerCommonShareDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Schedule of Basic and Diluted Loss Per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Liquidity and Uncertainties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LiquidityandUncertaintiesDetails</Role>
      <ShortName>Liquidity and Uncertainties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/LiquidityandUncertainties</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Product Revenue, Net - Schedule Of Gross To Net Adjustments Reserve (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/ProductRevenueNetScheduleOfGrossToNetAdjustmentsReserveDetails</Role>
      <ShortName>Product Revenue, Net - Schedule Of Gross To Net Adjustments Reserve (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Product Revenue, Net - Schedule of Concentrations of Credit Risk and Significant Customers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/ProductRevenueNetScheduleofConcentrationsofCreditRiskandSignificantCustomersDetails</Role>
      <ShortName>Product Revenue, Net - Schedule of Concentrations of Credit Risk and Significant Customers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Cash, Cash Equivalents, Restricted Cash and Marketable Securities - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecuritiesNarrativeDetails</Role>
      <ShortName>Cash, Cash Equivalents, Restricted Cash and Marketable Securities - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecuritiesTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - Cash, Cash Equivalents, Restricted Cash and Marketable Securities - Schedule of Cash, Cash Equivalents and Available-for-Sale Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CashCashEquivalentsRestrictedCashandMarketableSecuritiesScheduleofCashCashEquivalentsandAvailableforSaleMarketableSecuritiesDetails</Role>
      <ShortName>Cash, Cash Equivalents, Restricted Cash and Marketable Securities - Schedule of Cash, Cash Equivalents and Available-for-Sale Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Inventory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/InventoryDetails</Role>
      <ShortName>Inventory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/InventoryTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - Accrued Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/AccruedLiabilitiesDetails</Role>
      <ShortName>Accrued Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/AccruedLiabilitiesTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Long Term Debt - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LongTermDebtNarrativeDetails</Role>
      <ShortName>Long Term Debt - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Long Term Debt - Schedule of Maturities of Long-Term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/LongTermDebtScheduleofMaturitiesofLongTermDebtDetails</Role>
      <ShortName>Long Term Debt - Schedule of Maturities of Long-Term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Stockholders' Equity- Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockholdersEquityCommonStockDetails</Role>
      <ShortName>Stockholders' Equity- Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Stockholders' Equity - Preferred Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockholdersEquityPreferredStockDetails</Role>
      <ShortName>Stockholders' Equity - Preferred Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - Stockholders' Equity - 2024 Public Offering (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockholdersEquity2024PublicOfferingDetails</Role>
      <ShortName>Stockholders' Equity - 2024 Public Offering (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Stockholders' Equity - At The Market Issuance Sales Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockholdersEquityAtTheMarketIssuanceSalesAgreementDetails</Role>
      <ShortName>Stockholders' Equity - At The Market Issuance Sales Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Stock-based Compensation - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationNarrativeDetails</Role>
      <ShortName>Stock-based Compensation - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Stock-based Compensation - Schedule of Stock Option (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationScheduleofStockOptionDetails</Role>
      <ShortName>Stock-based Compensation - Schedule of Stock Option (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Stock-based Compensation - Schedule of Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationScheduleofRestrictedStockUnitsDetails</Role>
      <ShortName>Stock-based Compensation - Schedule of Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Stock-based Compensation - Schedule of Performance-Based Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationScheduleofPerformanceBasedRestrictedStockUnitsDetails</Role>
      <ShortName>Stock-based Compensation - Schedule of Performance-Based Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Stock-based Compensation - Schedule of Stock-Based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/StockbasedCompensationScheduleofStockBasedCompensationExpenseDetails</Role>
      <ShortName>Stock-based Compensation - Schedule of Stock-Based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/CommitmentsandContingencies</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Segment Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SegmentInformationNarrativeDetails</Role>
      <ShortName>Segment Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Segment Information - Schedule of Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SegmentInformationScheduleofSegmentInformationDetails</Role>
      <ShortName>Segment Information - Schedule of Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="mdgl-20250630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.madrigalpharma.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.madrigalpharma.com/role/SubsequentEvents</ParentRole>
      <Position>55</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="mdgl-20250630.htm">mdgl-20250630.htm</File>
    <File>mdgl-20250630.xsd</File>
    <File>mdgl-20250630_cal.xml</File>
    <File>mdgl-20250630_def.xml</File>
    <File>mdgl-20250630_lab.xml</File>
    <File>mdgl-20250630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="568">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="31">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
