<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>103</ContextCount>
  <ElementCount>202</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>37</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="bttx-20220630.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.bettertx.com/20220630/taxonomy/role/Role_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperationsAndComprehensiveLossUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/StatementCondensedConsolidatedStatementsOfStockholdersEquityDeficitUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/StatementCondensedConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100060 - Disclosure - Description of Business and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Description of Business and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100070 - Disclosure - Business Combination</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureBusinessCombination</Role>
      <ShortName>Business Combination</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>100080 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDebt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>100090 - Disclosure - SAFE Agreements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureSAFEAgreements</Role>
      <ShortName>SAFE Agreements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>100100 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>100110 - Disclosure - Net Loss Per Share Attributable to Common Shareholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureNetLossPerShareAttributableToCommonShareholders</Role>
      <ShortName>Net Loss Per Share Attributable to Common Shareholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>100120 - Disclosure - Share-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureShareBasedCompensation</Role>
      <ShortName>Share-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>100130 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>100140 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>100150 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureRelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>100160 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>100170 - Disclosure - Description of Business and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Description of Business and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>18</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>100190 - Disclosure - Net Loss Per Share Attributable to Common Shareholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureNetLossPerShareAttributableToCommonShareholdersTables</Role>
      <ShortName>Net Loss Per Share Attributable to Common Shareholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bettertx.com/20220630/taxonomy/role/DisclosureNetLossPerShareAttributableToCommonShareholders</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>100200 - Disclosure - Share-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureSharebasedCompensationTables</Role>
      <ShortName>Share-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureShareBasedCompensation</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>100210 - Disclosure - Description of Business and Summary of Significant Accounting Policies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails</Role>
      <ShortName>Description of Business and Summary of Significant Accounting Policies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>100220 - Disclosure - Business Combination - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureBusinessCombinationAdditionalInformationDetails</Role>
      <ShortName>Business Combination - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>100230 - Disclosure - Debt - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureDebtAdditionalInformationDetail</Role>
      <ShortName>Debt - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>100240 - Disclosure - SAFE Agreements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureSAFEAgreementsAdditionalInformationDetails</Role>
      <ShortName>SAFE Agreements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>100260 - Disclosure - Fair Value Measurements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureFairValueMeasurementsAdditionalInformationDetails</Role>
      <ShortName>Fair Value Measurements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>100270 - Disclosure - Net Loss Per Share Attributable to Common Shareholders - Summary of Computation of Basic and Diluted Loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureNetLossPerShareAttributableToCommonShareholdersSummaryOfComputationOfBasicAndDilutedLossDetails</Role>
      <ShortName>Net Loss Per Share Attributable to Common Shareholders - Summary of Computation of Basic and Diluted Loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>100280 - Disclosure - Net Loss Per Share Attributable to Common Shareholders - Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Weighted Average Shares Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureNetLossPerShareAttributableToCommonShareholdersScheduleOfPotentiallyDilutiveSecuritiesExcludedFromTheComputationOfDilutedWeighte</Role>
      <ShortName>Net Loss Per Share Attributable to Common Shareholders - Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Weighted Average Shares Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>100290 - Disclosure - Share-Based Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureShareBasedCompensationAdditionalInformationDetails</Role>
      <ShortName>Share-Based Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>100300 - Disclosure - Share-Based Compensation - Schedule of Stock Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureShareBasedCompensationScheduleOfStockOptionActivityDetails</Role>
      <ShortName>Share-Based Compensation - Schedule of Stock Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>100310 - Disclosure - Share-Based Compensation - Schedule of Stock Options Awards Valuation Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureSharebasedCompensationScheduleOfStockOptionsAwardsValuationAssumptionsDetails</Role>
      <ShortName>Share-Based Compensation - Schedule of Stock Options Awards Valuation Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>100320 - Disclosure - Share-Based Compensation - Schedule of Equity-based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureSharebasedCompensationScheduleOfEquitybasedCompensationExpenseDetails</Role>
      <ShortName>Share-Based Compensation - Schedule of Equity-based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>100330 - Disclosure - Income Taxes - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetails</Role>
      <ShortName>Income Taxes - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>100340 - Disclosure - Related Party Transactions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/Role_DisclosureRelatedPartyTransactionsAdditionalInformationDetails</Role>
      <ShortName>Related Party Transactions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="bttx-20220630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>100350 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bettertx.com/20220630/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</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" original="bttx-20220630.htm">bttx-20220630.htm</File>
    <File>bttx-20220630.xsd</File>
    <File>bttx-20220630_cal.xml</File>
    <File>bttx-20220630_def.xml</File>
    <File>bttx-20220630_lab.xml</File>
    <File>bttx-20220630_pre.xml</File>
    <File>bttx-ex31_1.htm</File>
    <File>bttx-ex31_2.htm</File>
    <File>bttx-ex32_1.htm</File>
    <File>bttx-ex32_2.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="341">http://fasb.org/us-gaap/2022</BaseTaxonomy>
    <BaseTaxonomy items="30">http://xbrl.sec.gov/dei/2022</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
