<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>179</ContextCount>
  <ElementCount>352</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>67</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>8</UnitCount>
  <MyReports>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00205 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedStatementsOfOperationsParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00300 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00305 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedStatementsOfCashFlowsParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00400 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' (DEFICIT) EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/StatementConsolidatedStatementsOfStockholdersDeficitEquity</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF STOCKHOLDERS' (DEFICIT) EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Company Overview</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureCompanyOverview</Role>
      <ShortName>Company Overview</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureInventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Prepaids and Other Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePrepaidsAndOtherAssets</Role>
      <ShortName>Prepaids and Other Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Restricted Cash</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRestrictedCash</Role>
      <ShortName>Restricted Cash</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Plant, Equipment, and Mine Development, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePlantEquipmentAndMineDevelopmentNet</Role>
      <ShortName>Plant, Equipment, and Mine Development, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Other Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureOtherLiabilities</Role>
      <ShortName>Other Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Asset Retirement Obligation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureAssetRetirementObligation</Role>
      <ShortName>Asset Retirement Obligation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>11001 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureStockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>11101 - Disclosure - Gold and Silver Sales</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureGoldAndSilverSales</Role>
      <ShortName>Gold and Silver Sales</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11201 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureStockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>11301 - Disclosure - Income taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>11401 - Disclosure - Earnings (Loss) Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureEarningsLossPerShare</Role>
      <ShortName>Earnings (Loss) Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>11501 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>11601 - Disclosure - Supplemental Cash Flow Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSupplementalCashFlowInformation</Role>
      <ShortName>Supplemental Cash Flow Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>11701 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>11801 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>11901 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>20202 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>30303 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureInventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureInventories</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>30403 - Disclosure - Prepaids and Other Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePrepaidsAndOtherAssetsTables</Role>
      <ShortName>Prepaids and Other Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosurePrepaidsAndOtherAssets</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>30503 - Disclosure - Restricted Cash (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRestrictedCashTables</Role>
      <ShortName>Restricted Cash (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureRestrictedCash</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>30603 - Disclosure - Plant, Equipment, and Mine Development, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePlantEquipmentAndMineDevelopmentNetTables</Role>
      <ShortName>Plant, Equipment, and Mine Development, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosurePlantEquipmentAndMineDevelopmentNet</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>30703 - Disclosure - Other Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureOtherLiabilitiesTables</Role>
      <ShortName>Other Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureOtherLiabilities</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>30803 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureDebt</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>30903 - Disclosure - Asset Retirement Obligation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureAssetRetirementObligationTables</Role>
      <ShortName>Asset Retirement Obligation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureAssetRetirementObligation</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>31103 - Disclosure - Gold and Silver Sales (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureGoldAndSilverSalesTables</Role>
      <ShortName>Gold and Silver Sales (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureGoldAndSilverSales</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>31403 - Disclosure - Earnings (Loss) Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureEarningsLossPerShareTables</Role>
      <ShortName>Earnings (Loss) Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureEarningsLossPerShare</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>31503 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurements</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>31603 - Disclosure - Supplemental Cash Flow Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSupplementalCashFlowInformationTables</Role>
      <ShortName>Supplemental Cash Flow Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureSupplementalCashFlowInformation</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>31803 - Disclosure - Related Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactionsTables</Role>
      <ShortName>Related Party Transactions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactions</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Company Overview (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureCompanyOverviewDetails</Role>
      <ShortName>Company Overview (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureCompanyOverview</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Summary of Significant Accounting Policies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails</Role>
      <ShortName>Summary of Significant Accounting Policies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureInventoriesDetails</Role>
      <ShortName>Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureInventoriesTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Prepaids and Other Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePrepaidsAndOtherAssetsDetails</Role>
      <ShortName>Prepaids and Other Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosurePrepaidsAndOtherAssetsTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRestrictedCashDetails</Role>
      <ShortName>Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureRestrictedCashTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Plant, Equipment, and Mine Development, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosurePlantEquipmentAndMineDevelopmentNetDetails</Role>
      <ShortName>Plant, Equipment, and Mine Development, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosurePlantEquipmentAndMineDevelopmentNetTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>40701 - Disclosure - Other Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureOtherLiabilitiesDetails</Role>
      <ShortName>Other Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureOtherLiabilitiesTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>40801 - Disclosure - Debt - Debt balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebtDebtBalancesDetails</Role>
      <ShortName>Debt - Debt balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>40802 - Disclosure - Debt - First lien term loan agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebtFirstLienTermLoanAgreementDetails</Role>
      <ShortName>Debt - First lien term loan agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>40803 - Disclosure - Debt - Second Lien Convertible Notes, 1.5 Lien Notes, 1.25 Lien Notes, Other notes payable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebtSecondLienConvertibleNotes15LienNotes125LienNotesOtherNotesPayableDetails</Role>
      <ShortName>Debt - Second Lien Convertible Notes, 1.5 Lien Notes, 1.25 Lien Notes, Other notes payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>40804 - Disclosure - Debt - Components of recorded interest expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureDebtComponentsOfRecordedInterestExpenseDetails</Role>
      <ShortName>Debt - Components of recorded interest expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>40901 - Disclosure - Asset Retirement Obligation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureAssetRetirementObligationDetails</Role>
      <ShortName>Asset Retirement Obligation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureAssetRetirementObligationTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>41001 - Disclosure - Stockholders' Equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureStockholdersEquityDetails</Role>
      <ShortName>Stockholders' Equity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureStockholdersEquity</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>41101 - Disclosure - Gold and Silver Sales (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureGoldAndSilverSalesDetails</Role>
      <ShortName>Gold and Silver Sales (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureGoldAndSilverSalesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>41201 - Disclosure - Stock-Based Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureStockBasedCompensationDetails</Role>
      <ShortName>Stock-Based Compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureStockBasedCompensation</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>41301 - Disclosure - Income taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureIncomeTaxesDetails</Role>
      <ShortName>Income taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureIncomeTaxes</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>41401 - Disclosure - Earnings (Loss) Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureEarningsLossPerShareDetails</Role>
      <ShortName>Earnings (Loss) Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureEarningsLossPerShareTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>41501 - Disclosure - Fair Value Measurements - Recurring fair value measurements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsRecurringFairValueMeasurementsDetails</Role>
      <ShortName>Fair Value Measurements - Recurring fair value measurements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>41502 - Disclosure - Fair Value Measurements - Accrued compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsAccruedCompensationDetails</Role>
      <ShortName>Fair Value Measurements - Accrued compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>41503 - Disclosure - Fair Value Measurements - Derivative instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsDerivativeInstrumentsDetails</Role>
      <ShortName>Fair Value Measurements - Derivative instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>41504 - Disclosure - Fair Value Measurements - Items disclosed at fair value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsItemsDisclosedAtFairValueDetails</Role>
      <ShortName>Fair Value Measurements - Items disclosed at fair value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>41505 - Disclosure - Fair Value Measurements - Additional information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureFairValueMeasurementsAdditionalInformationDetails</Role>
      <ShortName>Fair Value Measurements - Additional information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>41601 - Disclosure - Supplemental Cash Flow Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSupplementalCashFlowInformationDetails</Role>
      <ShortName>Supplemental Cash Flow Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureSupplementalCashFlowInformationTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>41701 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureCommitmentsAndContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureCommitmentsAndContingencies</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>41801 - Disclosure - Related Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactionsDetails</Role>
      <ShortName>Related Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactionsTables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>41802 - Disclosure - Related Party Transactions - Interest Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactionsInterestExpensesDetails</Role>
      <ShortName>Related Party Transactions - Interest Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>41803 - Disclosure - Related Party Transactions - Debt Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureRelatedPartyTransactionsDebtBalancesDetails</Role>
      <ShortName>Related Party Transactions - Debt Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>41901 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.mudrickcapital.com/role/DisclosureSubsequentEvents</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>41902 - Disclosure - Subsequent Events - MUDS transaction (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsMudsTransactionDetails</Role>
      <ShortName>Subsequent Events - MUDS transaction (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>41903 - Disclosure - Subsequent Events - Mudrick Capital Acquisition Holdings LLC (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsMudrickCapitalAcquisitionHoldingsLlcDetails</Role>
      <ShortName>Subsequent Events - Mudrick Capital Acquisition Holdings LLC (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>41904 - Disclosure - Subsequent Events - Sprott Credit Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsSprottCreditAgreementDetails</Role>
      <ShortName>Subsequent Events - Sprott Credit Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>41905 - Disclosure - Subsequent Events - Sprott Royalty Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsSprottRoyaltyAgreementDetails</Role>
      <ShortName>Subsequent Events - Sprott Royalty Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="hymc-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>41906 - Disclosure - Subsequent Events - Hycroft Warrant Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.mudrickcapital.com/role/DisclosureSubsequentEventsHycroftWarrantAgreementDetails</Role>
      <ShortName>Subsequent Events - Hycroft Warrant Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>hymc-20200331.xml</File>
    <File>hymc-20200331.xsd</File>
    <File>hymc-20200331_cal.xml</File>
    <File>hymc-20200331_def.xml</File>
    <File>hymc-20200331_lab.xml</File>
    <File>hymc-20200331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</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>
