<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>427</ContextCount>
  <ElementCount>417</ElementCount>
  <EntityCount>2</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>139</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-document-and-entity-information</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-balance-sheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Consolidated Balance Sheets (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-balance-sheets-parentheticals</Role>
      <ShortName>Consolidated Balance Sheets (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Consolidated Statements of Operations and Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-statements-of-operations-and-comprehensive-loss</Role>
      <ShortName>Consolidated Statements of Operations and Comprehensive Loss</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Consolidated Statements of Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-statements-of-stockholders-equity</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Consolidated Statements of Stockholders' Equity (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-statements-of-stockholders-equity-parentheticals</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-consolidated-statements-of-cash-flows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Disclosure - Note 1 - Business and Organization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-1-business-and-organization</Role>
      <ShortName>Note 1 - Business and Organization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>008 - Disclosure - Note 2 - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>009 - Disclosure - Note 3 - Sale of Stock for Cash</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-3-sale-of-stock-for-cash</Role>
      <ShortName>Note 3 - Sale of Stock for Cash</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010 - Disclosure - Note 4 - Debt Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-4-debt-obligations</Role>
      <ShortName>Note 4 - Debt Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>011 - Disclosure - Note 5 - Share-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation</Role>
      <ShortName>Note 5 - Share-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>012 - Disclosure - Note 6 - Warrants</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-6-warrants</Role>
      <ShortName>Note 6 - Warrants</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>013 - Disclosure - Note 7 - Accounts Payable and Accrued Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-7-accounts-payable-and-accrued-expenses</Role>
      <ShortName>Note 7 - Accounts Payable and Accrued Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>014 - Disclosure - Note 8 - Provision for Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes</Role>
      <ShortName>Note 8 - Provision for Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>015 - Disclosure - Note 9 - Noncontrolling Interest - BioLargo Energy Technologies, Inc. (BETI)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-9-noncontrolling-interest-biolargo-energy-technologies-inc-beti</Role>
      <ShortName>Note 9 - Noncontrolling Interest - BioLargo Energy Technologies, Inc. (BETI)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>016 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>017 - Disclosure - Note 11 - BioLargo Engineering, Science and Technologies, LLC</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-11-biolargo-engineering-science-and-technologies-llc</Role>
      <ShortName>Note 11 - BioLargo Engineering, Science and Technologies, LLC</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>018 - Disclosure - Note 12 - Business Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-12-business-segment-information</Role>
      <ShortName>Note 12 - Business Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>019 - Disclosure - Note 13 - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-13-leases</Role>
      <ShortName>Note 13 - Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020 - Disclosure - Note 14 - Legal Proceedings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-14-legal-proceedings</Role>
      <ShortName>Note 14 - Legal Proceedings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>021 - Disclosure - Note 15 - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-15-related-party-transactions</Role>
      <ShortName>Note 15 - Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>022 - Disclosure - Note 16 - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-16-subsequent-events</Role>
      <ShortName>Note 16 - Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>023 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-significant-accounting-policies-policies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>024 - Disclosure - Note 2 - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-tables</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>025 - Disclosure - Note 4 - Debt Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-4-debt-obligations-tables</Role>
      <ShortName>Note 4 - Debt Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-4-debt-obligations</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>026 - Disclosure - Note 5 - Share-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation-tables</Role>
      <ShortName>Note 5 - Share-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>027 - Disclosure - Note 6 - Warrants (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-6-warrants-tables</Role>
      <ShortName>Note 6 - Warrants (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-6-warrants</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>028 - Disclosure - Note 7 - Accounts Payable and Accrued Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-7-accounts-payable-and-accrued-expenses-tables</Role>
      <ShortName>Note 7 - Accounts Payable and Accrued Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-7-accounts-payable-and-accrued-expenses</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>029 - Disclosure - Note 8 - Provision for Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-tables</Role>
      <ShortName>Note 8 - Provision for Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>030 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-tables</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>031 - Disclosure - Note 12 - Business Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-12-business-segment-information-tables</Role>
      <ShortName>Note 12 - Business Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-12-business-segment-information</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>032 - Disclosure - Note 13 - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-13-leases-tables</Role>
      <ShortName>Note 13 - Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-13-leases</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>033 - Disclosure - Note 1 - Business and Organization (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-1-business-and-organization-details-textual</Role>
      <ShortName>Note 1 - Business and Organization (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-1-business-and-organization</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>034 - Disclosure - Note 2 - Summary of Significant Accounting Policies (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-details-textual</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-tables</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>035 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Summary of Cash Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-summary-of-cash-balances-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Summary of Cash Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>036 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Credit Concentration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-credit-concentration-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Credit Concentration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>037 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Inventory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-inventory-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Inventory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-tables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>038 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Other Non-current Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-other-noncurrent-assets-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Other Non-current Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>039 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Schedule of Antidilutive Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-schedule-of-antidilutive-securities-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Schedule of Antidilutive Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>040 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-stock-options-valuation-assumptions-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>041 - Disclosure - Note 2 - Summary of Significant Accounting Policies - Schedule of Equipment and Leasehold Improvements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-2-summary-of-significant-accounting-policies-schedule-of-equipment-and-leasehold-improvements-details</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies - Schedule of Equipment and Leasehold Improvements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>042 - Disclosure - Note 3 - Sale of Stock for Cash (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-3-sale-of-stock-for-cash-details-textual</Role>
      <ShortName>Note 3 - Sale of Stock for Cash (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-3-sale-of-stock-for-cash</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>043 - Disclosure - Note 4 - Debt Obligations (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-4-debt-obligations-details-textual</Role>
      <ShortName>Note 4 - Debt Obligations (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-4-debt-obligations-tables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>044 - Disclosure - Note 4 - Debt Obligations - Schedule of Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-4-debt-obligations-schedule-of-debt-details</Role>
      <ShortName>Note 4 - Debt Obligations - Schedule of Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>045 - Disclosure - Note 5 - Share-based Compensation (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation-details-textual</Role>
      <ShortName>Note 5 - Share-based Compensation (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation-tables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>046 - Disclosure - Note 5 - Share-based Compensation - Stock Options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-5-sharebased-compensation-stock-options-details</Role>
      <ShortName>Note 5 - Share-based Compensation - Stock Options (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>047 - Disclosure - Note 6 - Warrants (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-6-warrants-details-textual</Role>
      <ShortName>Note 6 - Warrants (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-6-warrants-tables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>048 - Disclosure - Note 6 - Warrants - Warrants Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-6-warrants-warrants-outstanding-details</Role>
      <ShortName>Note 6 - Warrants - Warrants Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>049 - Disclosure - Note 6 - Warrants - Assumptions Used to Determine Fair Value of Warrants (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-6-warrants-assumptions-used-to-determine-fair-value-of-warrants-details</Role>
      <ShortName>Note 6 - Warrants - Assumptions Used to Determine Fair Value of Warrants (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>050 - Disclosure - Note 7 - Accounts Payable and Accrued Expenses - Summary of Accounts Payable and Accrued Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-7-accounts-payable-and-accrued-expenses-summary-of-accounts-payable-and-accrued-expenses-details</Role>
      <ShortName>Note 7 - Accounts Payable and Accrued Expenses - Summary of Accounts Payable and Accrued Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>051 - Disclosure - Note 8 - Provision for Income Taxes (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-details-textual</Role>
      <ShortName>Note 8 - Provision for Income Taxes (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-tables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>052 - Disclosure - Note 8 - Provision for Income Taxes - Pretax Loss From Continuing Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-pretax-loss-from-continuing-operations-details</Role>
      <ShortName>Note 8 - Provision for Income Taxes - Pretax Loss From Continuing Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>053 - Disclosure - Note 8 - Provision for Income Taxes - Effective Income Tax Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-effective-income-tax-reconciliation-details</Role>
      <ShortName>Note 8 - Provision for Income Taxes - Effective Income Tax Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>054 - Disclosure - Note 8 - Provision for Income Taxes - Deferred Tax Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-8-provision-for-income-taxes-deferred-tax-assets-details</Role>
      <ShortName>Note 8 - Provision for Income Taxes - Deferred Tax Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>055 - Disclosure - Note 9 - Noncontrolling Interest - BioLargo Energy Technologies, Inc. (BETI) (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-9-noncontrolling-interest-biolargo-energy-technologies-inc-beti-details-textual</Role>
      <ShortName>Note 9 - Noncontrolling Interest - BioLargo Energy Technologies, Inc. (BETI) (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-9-noncontrolling-interest-biolargo-energy-technologies-inc-beti</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>056 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-details-textual</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-tables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>057 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical - Common Shares Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-common-shares-outstanding-details</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical - Common Shares Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>058 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical - Warrants Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-warrants-outstanding-details</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical - Warrants Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>059 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical - Schedule of Lease Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-schedule-of-lease-maturity-details</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical - Schedule of Lease Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>060 - Disclosure - Note 10 - Noncontrolling Interest - Clyra Medical - Summary of Accounts Payable and Accrued Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-10-noncontrolling-interest-clyra-medical-summary-of-accounts-payable-and-accrued-expenses-details</Role>
      <ShortName>Note 10 - Noncontrolling Interest - Clyra Medical - Summary of Accounts Payable and Accrued Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>061 - Disclosure - Note 11 - BioLargo Engineering, Science and Technologies, LLC (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-11-biolargo-engineering-science-and-technologies-llc-details-textual</Role>
      <ShortName>Note 11 - BioLargo Engineering, Science and Technologies, LLC (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-11-biolargo-engineering-science-and-technologies-llc</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>062 - Disclosure - Note 12 - Business Segment Information (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-12-business-segment-information-details-textual</Role>
      <ShortName>Note 12 - Business Segment Information (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-12-business-segment-information-tables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>063 - Disclosure - Note 12 - Business Segment Information - Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-12-business-segment-information-segment-information-details</Role>
      <ShortName>Note 12 - Business Segment Information - Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>064 - Disclosure - Note 13 - Leases (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-13-leases-details-textual</Role>
      <ShortName>Note 13 - Leases (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-13-leases-tables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>065 - Disclosure - Note 13 - Leases - Schedule of Future Minimum Lease Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-13-leases-schedule-of-future-minimum-lease-payments-details</Role>
      <ShortName>Note 13 - Leases - Schedule of Future Minimum Lease Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="blgo20260322_s1.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>066 - Disclosure - Note 14 - Legal Proceedings (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://biolargo.com/20251231/role/statement-note-14-legal-proceedings-details-textual</Role>
      <ShortName>Note 14 - Legal Proceedings (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://biolargo.com/20251231/role/statement-note-14-legal-proceedings</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="ex_935881.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>995210 - Document - Submission</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ffd/role/document/submissionTable</Role>
      <ShortName>Submission</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="ex_935881.htm">
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>995211 - Document - Offerings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ffd/role/document/feesOfferingTable</Role>
      <ShortName>Offerings</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="ex_935881.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>995215 - Document - Fees Summary</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ffd/role/document/feesSummaryTable</Role>
      <ShortName>Fees Summary</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>blgo-20251231.xsd</File>
    <File>blgo-20251231_cal.xml</File>
    <File>blgo-20251231_def.xml</File>
    <File>blgo-20251231_lab.xml</File>
    <File>blgo-20251231_pre.xml</File>
    <File doctype="S-1" isDefinitelyFs="true" isUsgaap="true" original="blgo20260322_s1.htm">blgo20260322_s1.htm</File>
    <File doctype="EX-FILING FEES" original="ex_935881.htm">ex_935881.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1214">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="3">http://xbrl.sec.gov/dei/2026</BaseTaxonomy>
    <BaseTaxonomy items="22">http://xbrl.sec.gov/ffd/2026</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
