<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>188</ContextCount>
  <ElementCount>322</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>72</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Condensed Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_StatementCondensedBalanceSheets</Role>
      <ShortName>Condensed Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Condensed Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_StatementCondensedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Condensed Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_StatementCondensedStatementsOfOperations</Role>
      <ShortName>Condensed Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Condensed Statements of Operations (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/StatementCondensedStatementsOfOperationsParenthetical</Role>
      <ShortName>Condensed Statements of Operations (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Condensed Statements of Stockholders' Equity (Deficit)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/StatementCondensedStatementsOfStockholdersEquityDeficit</Role>
      <ShortName>Condensed Statements of Stockholders' Equity (Deficit)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Condensed Statements of Stockholders' Equity (Deficit) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/StatementCondensedStatementsOfStockholdersEquityDeficitParenthetical</Role>
      <ShortName>Condensed Statements of Stockholders' Equity (Deficit) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>75070 - Statement - Condensed Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_StatementCondensedStatementsOfCashFlows</Role>
      <ShortName>Condensed Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.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>9</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.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>10</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Organization and Description of Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureOrganizationAndDescriptionOfBusiness</Role>
      <ShortName>Organization and Description of Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Summary of Significant Accounting Policies and Other Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAndOtherInformation</Role>
      <ShortName>Summary of Significant Accounting Policies and Other Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Recently Issued Accounting Standards</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureRecentlyIssuedAccountingStandards</Role>
      <ShortName>Recently Issued Accounting Standards</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureFairValue</Role>
      <ShortName>Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Supplementary Balance Sheet Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformation</Role>
      <ShortName>Supplementary Balance Sheet Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureEquity1</Role>
      <ShortName>Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Revenue and Accounts Receivable Credit Concentration</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentration</Role>
      <ShortName>Revenue and Accounts Receivable Credit Concentration</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Share-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureShareBasedCompensation</Role>
      <ShortName>Share-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Net Loss per Common Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureNetLossPerCommonShare</Role>
      <ShortName>Net Loss per Common Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Summary of Significant Accounting Policies and Other Information (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAndOtherInformationPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies and Other Information (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAndOtherInformation</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureFairValueTables</Role>
      <ShortName>Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureFairValue</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Supplementary Balance Sheet Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformationTables</Role>
      <ShortName>Supplementary Balance Sheet Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformation</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebt</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureLeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/DisclosureLeases</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Revenue and Accounts Receivable Credit Concentration (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentrationTables</Role>
      <ShortName>Revenue and Accounts Receivable Credit Concentration (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentration</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Share-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureShareBasedCompensationTables</Role>
      <ShortName>Share-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureShareBasedCompensation</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Net Loss per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureNetLossPerCommonShareTables</Role>
      <ShortName>Net Loss per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/DisclosureNetLossPerCommonShare</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSegmentReportingTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biodesix.com/20260331/taxonomy/role/DisclosureSegmentReporting</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Summary of Significant Accounting Policies and Other Information- Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAndOtherInformationAdditionalInformationDetails</Role>
      <ShortName>Summary of Significant Accounting Policies and Other Information- Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Fair Value - Summary of Fair Value of Outstanding Borrowings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureFairValueSummaryOfFairValueOfOutstandingBorrowingsDetails</Role>
      <ShortName>Fair Value - Summary of Fair Value of Outstanding Borrowings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Fair Value - Schedule of Changes in Warrant Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureFairValueScheduleOfChangesInWarrantLiabilitiesDetails</Role>
      <ShortName>Fair Value - Schedule of Changes in Warrant Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Fair Value - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureFairValueAdditionalInformationDetails</Role>
      <ShortName>Fair Value - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Supplementary Balance Sheet Information - Property and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformationPropertyAndEquipmentDetails</Role>
      <ShortName>Supplementary Balance Sheet Information - Property and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Supplementary Balance Sheet Information - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformationAdditionalInformationDetails</Role>
      <ShortName>Supplementary Balance Sheet Information - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Supplementary Balance Sheet Information - Intangible Assets, Excluding Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformationIntangibleAssetsExcludingGoodwillDetails</Role>
      <ShortName>Supplementary Balance Sheet Information - Intangible Assets, Excluding Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Supplementary Balance Sheet Information - Schedule of Amortization Related to Remaining Net Intangible Assets Schedule to Amortize (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSupplementaryBalanceSheetInformationScheduleOfAmortizationRelatedToRemainingNetIntangibleAssetsScheduleToAmortizeDetails</Role>
      <ShortName>Supplementary Balance Sheet Information - Schedule of Amortization Related to Remaining Net Intangible Assets Schedule to Amortize (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Supplementary Balance Sheet Information - Accrued Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureSupplementaryBalanceSheetInformationAccruedLiabilitiesDetails</Role>
      <ShortName>Supplementary Balance Sheet Information - Accrued Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995825 - Disclosure - Debt - Summary of Long-term Notes Payable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebtSummaryOfLongTermNotesPayableDetails</Role>
      <ShortName>Debt - Summary of Long-term Notes Payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Debt - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebtAdditionalInformationDetails</Role>
      <ShortName>Debt - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Debt - Scheduled Principal Repayments (Maturities) of Long-term Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureDebtScheduledPrincipalRepaymentsMaturitiesOfLongTermObligationsDetails</Role>
      <ShortName>Debt - Scheduled Principal Repayments (Maturities) of Long-term Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Leases - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureLeasesAdditionalInformationDetails</Role>
      <ShortName>Leases - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Leases - Summary of Future Minimum Lease Payments for Operating Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureLeasesSummaryOfFutureMinimumLeasePaymentsForOperatingLeasesDetails</Role>
      <ShortName>Leases - Summary of Future Minimum Lease Payments for Operating Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Convertible Preferred Stock - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureConvertiblePreferredStockAdditionalInformationDetails</Role>
      <ShortName>Convertible Preferred Stock - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Equity - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureEquityAdditionalInformationDetails</Role>
      <ShortName>Equity - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Revenue and Accounts Receivable Credit Concentration - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentrationAdditionalInformationDetails</Role>
      <ShortName>Revenue and Accounts Receivable Credit Concentration - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Revenue and Accounts Receivable Credit Concentration - Summary of Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentrationSummaryOfRevenueDetails</Role>
      <ShortName>Revenue and Accounts Receivable Credit Concentration - Summary of Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Revenue and Accounts Receivable Credit Concentration - Summary of Revenue and Accounts Receivable by Third-party Payors and Other Customers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureRevenueAndAccountsReceivableCreditConcentrationSummaryOfRevenueAndAccountsReceivableByThirdPartyPayorsAndOtherCustomersDetails</Role>
      <ShortName>Revenue and Accounts Receivable Credit Concentration - Summary of Revenue and Accounts Receivable by Third-party Payors and Other Customers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Share-Based Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureShareBasedCompensationAdditionalInformationDetails</Role>
      <ShortName>Share-Based Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Share-Based Compensation - Summary of Share-based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSharebasedCompensationSummaryOfSharebasedCompensationExpenseDetails</Role>
      <ShortName>Share-Based Compensation - Summary of Share-based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Share-Based Compensation - Summary of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfStockOptionActivityDetails</Role>
      <ShortName>Share-Based Compensation - Summary of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Share-Based Compensation - Summary of Restricted Stock Units Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSharebasedCompensationSummaryOfRestrictedStockUnitsActivityDetails</Role>
      <ShortName>Share-Based Compensation - Summary of Restricted Stock Units Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Net Loss per Common Share - Schedule of Computation of Basic and Diluted Loss per Share Attributable to Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureNetLossPerCommonShareScheduleOfComputationOfBasicAndDilutedLossPerShareAttributableToStockholdersDetails</Role>
      <ShortName>Net Loss per Common Share - Schedule of Computation of Basic and Diluted Loss per Share Attributable to Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>996015 - Disclosure - Net Loss per Common Share - Schedule of Common Stock Equivalents Excluded from Diluted Net Loss Attributable to Common Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureNetLossPerCommonShareScheduleOfCommonStockEquivalentsExcludedFromDilutedNetLossAttributableToCommonStockholdersDetails</Role>
      <ShortName>Net Loss per Common Share - Schedule of Common Stock Equivalents Excluded from Diluted Net Loss Attributable to Common Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>996025 - Disclosure - Income Taxes - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetails</Role>
      <ShortName>Income Taxes - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>996035 - Disclosure - Segment Reporting - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSegmentReportingAdditionalInformationDetails</Role>
      <ShortName>Segment Reporting - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>996045 - Disclosure - Segment Reporting - Summary of Significant Expenses and Other Segment Items (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/DisclosureSegmentReportingSummaryOfSignificantExpensesAndOtherSegmentItemsDetails</Role>
      <ShortName>Segment Reporting - Summary of Significant Expenses and Other Segment Items (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="bdsx-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biodesix.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</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="bdsx-20260331.htm">bdsx-20260331.htm</File>
    <File>bdsx-20260331.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="542">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
