<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>193</ContextCount>
  <ElementCount>380</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>96</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/Cover</Role>
      <ShortName>Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSUNAUDITED</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (UNAUDITED)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSSUNAUDITED</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (UNAUDITED)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS??? EQUITY (UNAUDITED)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITYUNAUDITED</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS??? EQUITY (UNAUDITED)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1006007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2111102 - Disclosure - Adoption of New Accounting Standards</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/AdoptionofNewAccountingStandards</Role>
      <ShortName>Adoption of New Accounting Standards</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2112103 - Disclosure - Reverse Recapitalization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/ReverseRecapitalization</Role>
      <ShortName>Reverse Recapitalization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2116104 - Disclosure - Fair Value of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstruments</Role>
      <ShortName>Fair Value of Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2122105 - Disclosure - Balance Sheet Components</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponents</Role>
      <ShortName>Balance Sheet Components</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2129106 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2136107 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2144108 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2146109 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/StockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2150110 - Disclosure - Equity Plans and Stock-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensation</Role>
      <ShortName>Equity Plans and Stock-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2157111 - Disclosure - Net Income (Loss) Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/NetIncomeLossPerShare</Role>
      <ShortName>Net Income (Loss) Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2162112 - Disclosure - 401(k) Plan</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/A401kPlan</Role>
      <ShortName>401(k) Plan</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2164113 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://proterra.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2313302 - Disclosure - Reverse Recapitalization (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/ReverseRecapitalizationTables</Role>
      <ShortName>Reverse Recapitalization (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/ReverseRecapitalization</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2317303 - Disclosure - Fair Value of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstrumentsTables</Role>
      <ShortName>Fair Value of Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/FairValueofFinancialInstruments</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2323304 - Disclosure - Balance Sheet Components (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsTables</Role>
      <ShortName>Balance Sheet Components (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/BalanceSheetComponents</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2330305 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/Debt</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2337306 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/Leases</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2347307 - Disclosure - Stockholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/StockholdersEquityTables</Role>
      <ShortName>Stockholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/StockholdersEquity</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2351308 - Disclosure - Equity Plans and Stock-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationTables</Role>
      <ShortName>Equity Plans and Stock-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/EquityPlansandStockbasedCompensation</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2358309 - Disclosure - Net Income (Loss) Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/NetIncomeLossPerShareTables</Role>
      <ShortName>Net Income (Loss) Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://proterra.com/role/NetIncomeLossPerShare</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2404401 - Disclosure - Summary of Significant Accounting Policies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Summary of Significant Accounting Policies - Revenue Disaggregated by Geography (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesRevenueDisaggregatedbyGeographyDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Revenue Disaggregated by Geography (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - Summary of Significant Accounting Policies - Credit Risk and Concentration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesCreditRiskandConcentrationDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Credit Risk and Concentration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2407404 - Disclosure - Summary of Significant Accounting Policies - Deferred Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesDeferredRevenueDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Deferred Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2408405 - Disclosure - Summary of Significant Accounting Policies - Revenue Recognition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesRevenueRecognitionDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Revenue Recognition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2409406 - Disclosure - Summary of Significant Accounting Policies - Revenue of Business Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesRevenueofBusinessUnitsDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Revenue of Business Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2410407 - Disclosure - Summary of Significant Accounting Policies - Product Warranties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SummaryofSignificantAccountingPoliciesProductWarrantiesDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Product Warranties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2414408 - Disclosure - Reverse Recapitalization - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/ReverseRecapitalizationNarrativeDetails</Role>
      <ShortName>Reverse Recapitalization - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2415409 - Disclosure - Reverse Recapitalization - Shares Issued in Merger (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/ReverseRecapitalizationSharesIssuedinMergerDetails</Role>
      <ShortName>Reverse Recapitalization - Shares Issued in Merger (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2418410 - Disclosure - Fair Value of Financial Instruments - Financial Assets Measured at Fair Value on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstrumentsFinancialAssetsMeasuredatFairValueonaRecurringBasisDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Financial Assets Measured at Fair Value on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2419411 - Disclosure - Fair Value of Financial Instruments - Cash Equivalents and Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstrumentsCashEquivalentsandMarketableSecuritiesDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Cash Equivalents and Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2420412 - Disclosure - Fair Value of Financial Instruments - Contractual Maturities of Short-Term Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstrumentsContractualMaturitiesofShortTermInvestmentsDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Contractual Maturities of Short-Term Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2421413 - Disclosure - Fair Value of Financial Instruments - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/FairValueofFinancialInstrumentsNarrativeDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2424414 - Disclosure - Balance Sheet Components - Cash and Cash Equivalents, and Restricted Cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsCashandCashEquivalentsandRestrictedCashDetails</Role>
      <ShortName>Balance Sheet Components - Cash and Cash Equivalents, and Restricted Cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2425415 - Disclosure - Balance Sheet Components - Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsInventoriesDetails</Role>
      <ShortName>Balance Sheet Components - Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2426416 - Disclosure - Balance Sheet Components - Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsPropertyPlantandEquipmentDetails</Role>
      <ShortName>Balance Sheet Components - Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2427417 - Disclosure - Balance Sheet Components - Accrued Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsAccruedLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Components - Accrued Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2428418 - Disclosure - Balance Sheet Components - Other Long-Term Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/BalanceSheetComponentsOtherLongTermLiabilitiesDetails</Role>
      <ShortName>Balance Sheet Components - Other Long-Term Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2431419 - Disclosure - Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/DebtDetails</Role>
      <ShortName>Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/DebtTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2432420 - Disclosure - Debt - Senior Credit Facility (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/DebtSeniorCreditFacilityDetails</Role>
      <ShortName>Debt - Senior Credit Facility (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2433421 - Disclosure - Debt - Small Business Administration Loan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/DebtSmallBusinessAdministrationLoanDetails</Role>
      <ShortName>Debt - Small Business Administration Loan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2434422 - Disclosure - Debt - Convertible Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://proterra.com/role/DebtConvertibleNotesDetails</Role>
      <ShortName>Debt - Convertible Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2435423 - Disclosure - Debt - Future Principal Repayments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/DebtFuturePrincipalRepaymentsDetails</Role>
      <ShortName>Debt - Future Principal Repayments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2438424 - Disclosure - Leases - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesNarrativeDetails</Role>
      <ShortName>Leases - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2439425 - Disclosure - Leases - Net Investment In Lease (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesNetInvestmentInLeaseDetails</Role>
      <ShortName>Leases - Net Investment In Lease (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2440426 - Disclosure - Leases - Lessor Future Minimum Payments Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesLessorFutureMinimumPaymentsReceivableDetails</Role>
      <ShortName>Leases - Lessor Future Minimum Payments Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2441427 - Disclosure - Leases - Maturities Of Operating Lease Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails</Role>
      <ShortName>Leases - Maturities Of Operating Lease Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2442428 - Disclosure - Leases - Supplemental Cash Flow Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesSupplementalCashFlowInformationDetails</Role>
      <ShortName>Leases - Supplemental Cash Flow Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2443429 - Disclosure - Leases - Operating Lease Right-of-use Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/LeasesOperatingLeaseRightofuseAssetsandLiabilitiesDetails</Role>
      <ShortName>Leases - Operating Lease Right-of-use Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2445430 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/CommitmentsandContingencies</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2448431 - Disclosure - Stockholders' Equity - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/StockholdersEquityNarrativeDetails</Role>
      <ShortName>Stockholders' Equity - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2449432 - Disclosure - Stockholders' Equity - Reserved Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/StockholdersEquityReservedSharesDetails</Role>
      <ShortName>Stockholders' Equity - Reserved Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2452433 - Disclosure - Equity Plans and Stock-based Compensation - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationNarrativeDetails</Role>
      <ShortName>Equity Plans and Stock-based Compensation - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2453434 - Disclosure - Equity Plans and Stock-based Compensation - Outstanding Option Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationOutstandingOptionActivityDetails</Role>
      <ShortName>Equity Plans and Stock-based Compensation - Outstanding Option Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2454435 - Disclosure - Equity Plans and Stock-based Compensation - Assumptions Used in Fair Value Measurement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationAssumptionsUsedinFairValueMeasurementDetails</Role>
      <ShortName>Equity Plans and Stock-based Compensation - Assumptions Used in Fair Value Measurement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2455436 - Disclosure - Equity Plans and Stock-based Compensation - Stock-based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationStockbasedCompensationExpenseDetails</Role>
      <ShortName>Equity Plans and Stock-based Compensation - Stock-based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2456437 - Disclosure - Equity Plans and Stock-based Compensation - RSU Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/EquityPlansandStockbasedCompensationRSUActivityDetails</Role>
      <ShortName>Equity Plans and Stock-based Compensation - RSU Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2459438 - Disclosure - Net Income (Loss) Per Share - Calculation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/NetIncomeLossPerShareCalculationDetails</Role>
      <ShortName>Net Income (Loss) Per Share - Calculation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/NetIncomeLossPerShareTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2460439 - Disclosure - Net Income (Loss) Per Share - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/NetIncomeLossPerShareNarrativeDetails</Role>
      <ShortName>Net Income (Loss) Per Share - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/NetIncomeLossPerShareTables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2461440 - Disclosure - Net Income (Loss) Per Share - Potentially Dilutive Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/NetIncomeLossPerSharePotentiallyDilutiveSecuritiesDetails</Role>
      <ShortName>Net Income (Loss) Per Share - Potentially Dilutive Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/NetIncomeLossPerShareTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2463441 - Disclosure - 401(k) Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/A401kPlanDetails</Role>
      <ShortName>401(k) Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/A401kPlan</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="ptra-20220331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2465442 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://proterra.com/role/SubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://proterra.com/role/SubsequentEvents</ParentRole>
      <Position>72</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="ptra-20220331.htm">ptra-20220331.htm</File>
    <File>a2022q1exhibit-311.htm</File>
    <File>a2022q1exhibit-312.htm</File>
    <File>a2022q1exhibit-321.htm</File>
    <File>a2022q1exhibit-322.htm</File>
    <File>ptra-20220331.xsd</File>
    <File>ptra-20220331_cal.xml</File>
    <File>ptra-20220331_def.xml</File>
    <File>ptra-20220331_lab.xml</File>
    <File>ptra-20220331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="654">http://fasb.org/us-gaap/2021-01-31</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2021q4</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
