<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>244</ContextCount>
  <ElementCount>236</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>68</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/StatementCondensedConsolidatedBalanceSheets</Role>
      <ShortName>Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100030 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100040 - Statement - Condensed Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperations</Role>
      <ShortName>Condensed Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100060 - Statement - Condensed Consolidated Statements of Stockholders' Equity (Deficit)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/StatementCondensedConsolidatedStatementsOfStockholdersEquityDeficit</Role>
      <ShortName>Condensed Consolidated Statements of Stockholders' Equity (Deficit)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100070 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.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>7</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.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>8</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Organization and Liquidity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureOrganizationAndLiquidity</Role>
      <ShortName>Organization and Liquidity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Balance Sheet Components</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureBalanceSheetComponents</Role>
      <ShortName>Balance Sheet Components</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Notes Payable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayable</Role>
      <ShortName>Notes Payable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Strategic License Agreements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStrategicLicenseAgreements</Role>
      <ShortName>Strategic License Agreements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Net Loss Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShare</Role>
      <ShortName>Net Loss Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureRelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureFairValueMeasurements</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Balance Sheet Components (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureBalanceSheetComponentsTables</Role>
      <ShortName>Balance Sheet Components (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureBalanceSheetComponents</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Notes Payable (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayableTables</Role>
      <ShortName>Notes Payable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayable</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureCommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Stockholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquityTables</Role>
      <ShortName>Stockholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquity</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReportingTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReporting</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensationTables</Role>
      <ShortName>Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensation</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Net Loss Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShareTables</Role>
      <ShortName>Net Loss Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShare</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Organization and Liquidity - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureOrganizationAndLiquidityAdditionalInformationDetails</Role>
      <ShortName>Organization and Liquidity - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Reverse Merger (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureReverseMergerAdditionalInformationDetails</Role>
      <ShortName>Reverse Merger (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Fair Value Measurements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureFairValueMeasurementsAdditionalInformationDetails</Role>
      <ShortName>Fair Value Measurements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Fair Value Measurements - Summary of Changes in the Fair Value of the Rights from Private Placement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfChangesInTheFairValueOfTheRightsFromPrivatePlacementDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Changes in the Fair Value of the Rights from Private Placement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Fair Value Measurements - Summary of Changes in Fair Value of 2020 Notes Payable Measured Using Level 3 Inputs (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfChangesInFairValueOf2020NotesPayableMeasuredUsingLevel3InputsDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Changes in Fair Value of 2020 Notes Payable Measured Using Level 3 Inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureBalanceSheetComponentsScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Balance Sheet Components (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureBalanceSheetComponentsAdditionalInformationDetails</Role>
      <ShortName>Balance Sheet Components (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureBalanceSheetComponentsTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Notes Payable - Schedule of Notes Payable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayableScheduleOfNotesPayableDetails</Role>
      <ShortName>Notes Payable - Schedule of Notes Payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Notes Payable - Schedule of Expected Future Minimum Principal (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayableScheduleOfExpectedFutureMinimumPrincipalDetails</Role>
      <ShortName>Notes Payable - Schedule of Expected Future Minimum Principal (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Notes Payable - Additional Information (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNotesPayableAdditionalInformationDetails</Role>
      <ShortName>Notes Payable - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Commitments and Contingencies (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureCommitmentsAndContingenciesTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Commitments and Contingencies - Schedule of Operating Leases Supplemental Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfOperatingLeasesSupplementalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Schedule of Operating Leases Supplemental Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Strategic License Agreements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStrategicLicenseAgreementsAdditionalInformationDetails</Role>
      <ShortName>Strategic License Agreements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Stockholders' Equity - Schedule of Issued and Outstanding Warrants to Purchase Shares of the Company's Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquityScheduleOfIssuedAndOutstandingWarrantsToPurchaseSharesOfTheCompanysCommonStockDetails</Role>
      <ShortName>Stockholders' Equity - Schedule of Issued and Outstanding Warrants to Purchase Shares of the Company's Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Stockholders' Equity - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetails</Role>
      <ShortName>Stockholders' Equity - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureStockholdersEquityScheduleOfCommonStockReservedForFutureIssuanceDetails</Role>
      <ShortName>Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Segment Reporting - Schedule of information about the Companys segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReportingScheduleOfInformationAboutTheCompanysSegmentDetails</Role>
      <ShortName>Segment Reporting - Schedule of information about the Companys segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>996065 - Disclosure - Segment Reporting - Summary Of Significant Operating Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReportingSummaryOfSignificantOperatingExpensesDetails</Role>
      <ShortName>Segment Reporting - Summary Of Significant Operating Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>996075 - Disclosure - Segment Reporting (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReportingAdditionalInformationDetails</Role>
      <ShortName>Segment Reporting (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureSegmentReportingTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>996085 - Disclosure - Stock-Based Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensationAdditionalInformationDetails</Role>
      <ShortName>Stock-Based Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>996095 - Disclosure - Stock-Based Compensation - Summary of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensationSummaryOfStockOptionActivityDetails</Role>
      <ShortName>Stock-Based Compensation - Summary of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>996125 - Disclosure - Stock-Based Compensation - Summary of Total Stock-Based Compensation (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureStockBasedCompensationSummaryOfTotalStockBasedCompensationDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Total Stock-Based Compensation (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>996185 - Disclosure - Net Loss Per Share - Summary of Basic and Diluted Net Loss per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShareSummaryOfBasicAndDilutedNetLossPerShareDetail</Role>
      <ShortName>Net Loss Per Share - Summary of Basic and Diluted Net Loss per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>996195 - Disclosure - Net Loss Per Share - Summary of Basic and Diluted Net Loss per Share (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureNetLossPerShareSummaryOfBasicAndDilutedNetLossPerShareParentheticalDetails</Role>
      <ShortName>Net Loss Per Share - Summary of Basic and Diluted Net Loss per Share (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>996205 - Disclosure - Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted-average Shares Outstanding (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShareScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfDilutedWeightedAverageSharesOutstandingDetail</Role>
      <ShortName>Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted-average Shares Outstanding (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>996215 - Disclosure - Net Loss Per Share (Additional Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/DisclosureNetLossPerShareAdditionalInformationDetails</Role>
      <ShortName>Net Loss Per Share (Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureNetLossPerShareTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>996245 - Disclosure - Related Party Transactions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureRelatedPartyTransactionsAdditionalInformationDetails</Role>
      <ShortName>Related Party Transactions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="kant-20250331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>996255 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kinetabio.com/20250331/taxonomy/role/Role_DisclosureSubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</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="kant-20250331.htm">kant-20250331.htm</File>
    <File>kant-20250331.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="466">http://fasb.org/us-gaap/2024</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2024</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2024</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
