<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>75</ContextCount>
  <ElementCount>239</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>29</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedBalanceSheets</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfOperations</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00205 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - Share-Based Compensation Expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfOperationsShareBasedCompensationExpense</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - Share-Based Compensation Expense</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00210 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - Restructuring Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfOperationsRestructuringExpenses</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - Restructuring Expenses</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00300 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfComprehensiveIncomeLoss</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00400 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfShareholdersEquity</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>00500 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/StatementCondensedConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Organization and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Net Loss per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureNetLossPerShare</Role>
      <ShortName>Net Loss per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Revenue</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenue</Role>
      <ShortName>Revenue</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Cash, Cash Equivalents, and Restricted Cash</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCashCashEquivalentsAndRestrictedCash</Role>
      <ShortName>Cash, Cash Equivalents, and Restricted Cash</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Investments and Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurements</Role>
      <ShortName>Investments and Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Subleases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSubleases</Role>
      <ShortName>Subleases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Share-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensation</Role>
      <ShortName>Share-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>11001 - Disclosure - Organizational Restructuring</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationalRestructuring</Role>
      <ShortName>Organizational Restructuring</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11101 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>20102 - Disclosure - Organization and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>30203 - Disclosure - Net Loss per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureNetLossPerShareTables</Role>
      <ShortName>Net Loss per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureNetLossPerShare</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>30303 - Disclosure - Revenue (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenueTables</Role>
      <ShortName>Revenue (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureRevenue</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>30403 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureSegmentInformation</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>30503 - Disclosure - Cash, Cash Equivalents, and Restricted Cash (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCashCashEquivalentsAndRestrictedCashTables</Role>
      <ShortName>Cash, Cash Equivalents, and Restricted Cash (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureCashCashEquivalentsAndRestrictedCash</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>30603 - Disclosure - Investments and Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsTables</Role>
      <ShortName>Investments and Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurements</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>30703 - Disclosure - Subleases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSubleasesTables</Role>
      <ShortName>Subleases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureSubleases</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>30803 - Disclosure - Share-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensationTables</Role>
      <ShortName>Share-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureShareBasedCompensation</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>31003 - Disclosure - Organizational Restructuring (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationalRestructuringTables</Role>
      <ShortName>Organizational Restructuring (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureOrganizationalRestructuring</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Organization and Summary of Significant Accounting Policies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesDetails</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Net Loss per Share - Income (Loss) Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureNetLossPerShareIncomeLossPerShareDetails</Role>
      <ShortName>Net Loss per Share - Income (Loss) Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Revenue - Collaborative Arrangements - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenueCollaborativeArrangementsGeneralInformationDetails</Role>
      <ShortName>Revenue - Collaborative Arrangements - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>40302 - Disclosure - Revenue - Collaborative Arrangements - Revenue Recognized (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenueCollaborativeArrangementsRevenueRecognizedDetails</Role>
      <ShortName>Revenue - Collaborative Arrangements - Revenue Recognized (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>40303 - Disclosure - Revenue - Disaggregation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenueDisaggregationDetails</Role>
      <ShortName>Revenue - Disaggregation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>40304 - Disclosure - Revenue - Implied Share of Net Sales (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureRevenueImpliedShareOfNetSalesDetails</Role>
      <ShortName>Revenue - Implied Share of Net Sales (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Segment Information - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSegmentInformationGeneralInformationDetails</Role>
      <ShortName>Segment Information - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>40402 - Disclosure - Segment Information - Tabular Disclosure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSegmentInformationTabularDisclosureDetails</Role>
      <ShortName>Segment Information - Tabular Disclosure (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Cash, Cash Equivalents, and Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCashCashEquivalentsAndRestrictedCashDetails</Role>
      <ShortName>Cash, Cash Equivalents, and Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.theravance.com/role/DisclosureCashCashEquivalentsAndRestrictedCashTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Investments and Fair Value Measurements - Fair Value to Amortized Cost - Available-for-Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsFairValueToAmortizedCostAvailableForSaleSecuritiesDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Fair Value to Amortized Cost - Available-for-Sale Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>40602 - Disclosure - Investments and Fair Value Measurements - Fair Value to Amortized Cost - Total (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsFairValueToAmortizedCostTotalDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Fair Value to Amortized Cost - Total (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>40603 - Disclosure - Investments and Fair Value Measurements - Maturities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsMaturitiesDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>40604 - Disclosure - Investments and Fair Value Measurements - Transfers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsTransfersDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Transfers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>40605 - Disclosure - Investments and Fair Value Measurements - Unrealized Loss Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsUnrealizedLossPositionDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Unrealized Loss Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>40606 - Disclosure - Investments and Fair Value Measurements - Available-for-Sale Securities - Credit Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsAvailableForSaleSecuritiesCreditLossesDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Available-for-Sale Securities - Credit Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40607 - Disclosure - Investments and Fair Value Measurements - Available-for-Sale Securities - Sales of Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsAvailableForSaleSecuritiesSalesOfMarketableSecuritiesDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Available-for-Sale Securities - Sales of Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40608 - Disclosure - Investments and Fair Value Measurements - Future Royalty Payment Contingency (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsFutureRoyaltyPaymentContingencyDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Future Royalty Payment Contingency (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>40609 - Disclosure - Investments and Fair Value Measurements - Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Roll Forward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationRollForwardDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Roll Forward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>40610 - Disclosure - Investments and Fair Value Measurements - Contract Derivative - Fair Value Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsContractDerivativeFairValueAssumptionsDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Contract Derivative - Fair Value Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>40611 - Disclosure - Investments and Fair Value Measurements - Contract Derivative - Fair Value and Location on Consolidated Balance Sheets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureInvestmentsAndFairValueMeasurementsContractDerivativeFairValueAndLocationOnConsolidatedBalanceSheetsDetails</Role>
      <ShortName>Investments and Fair Value Measurements - Contract Derivative - Fair Value and Location on Consolidated Balance Sheets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>40701 - Disclosure - Subleases - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSubleasesGeneralInformationDetails</Role>
      <ShortName>Subleases - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>40702 - Disclosure - Subleases - Sublease Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureSubleasesSubleaseIncomeDetails</Role>
      <ShortName>Subleases - Sublease Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>40801 - Disclosure - Share-Based Compensation - Share-Based Compensation Expense Included in Statement of Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensationShareBasedCompensationExpenseIncludedInStatementOfOperationsDetails</Role>
      <ShortName>Share-Based Compensation - Share-Based Compensation Expense Included in Statement of Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>40802 - Disclosure - Share-Based Compensation - Organizational Restructuring (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensationOrganizationalRestructuringDetails</Role>
      <ShortName>Share-Based Compensation - Organizational Restructuring (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>40803 - Disclosure - Share-Based Compensation - Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensationOptionActivityDetails</Role>
      <ShortName>Share-Based Compensation - Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>40804 - Disclosure - Share-Based Compensation - RSU Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureShareBasedCompensationRsuActivityDetails</Role>
      <ShortName>Share-Based Compensation - RSU Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>40901 - Disclosure - Income Taxes - Income Tax Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureIncomeTaxesIncomeTaxExpenseDetails</Role>
      <ShortName>Income Taxes - Income Tax Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>40902 - Disclosure - Income Taxes - Undistributed Earnings of Foreign Subsidiaries (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureIncomeTaxesUndistributedEarningsOfForeignSubsidiariesDetails</Role>
      <ShortName>Income Taxes - Undistributed Earnings of Foreign Subsidiaries (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>41001 - Disclosure - Organizational Restructuring - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationalRestructuringGeneralInformationDetails</Role>
      <ShortName>Organizational Restructuring - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>41002 - Disclosure - Organizational Restructuring - Restructuring Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationalRestructuringRestructuringExpensesDetails</Role>
      <ShortName>Organizational Restructuring - Restructuring Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>41003 - Disclosure - Organizational Restructuring - Accrued Restructuring Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureOrganizationalRestructuringAccruedRestructuringExpensesDetails</Role>
      <ShortName>Organizational Restructuring - Accrued Restructuring Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>41101 - Disclosure - Commitments and Contingencies - Legal Proceedings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCommitmentsAndContingenciesLegalProceedingsDetails</Role>
      <ShortName>Commitments and Contingencies - Legal Proceedings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="tbph-20260331x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>41102 - Disclosure - Commitments and Contingencies - Litigation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.theravance.com/role/DisclosureCommitmentsAndContingenciesLitigationDetails</Role>
      <ShortName>Commitments and Contingencies - Litigation (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>tbph-20260331.xsd</File>
    <File>tbph-20260331_cal.xml</File>
    <File>tbph-20260331_def.xml</File>
    <File>tbph-20260331_lab.xml</File>
    <File>tbph-20260331_pre.xml</File>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="tbph-20260331x10q.htm">tbph-20260331x10q.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="437">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="31">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
