<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-09-02</periodOfReport>

    <issuer>
        <issuerCik>0001053352</issuerCik>
        <issuerName>HERITAGE COMMERCE CORP</issuerName>
        <issuerTradingSymbol>HTBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000949197</rptOwnerCik>
            <rptOwnerName>WYCOFF W KIRK</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PATRIOT FINANCIAL PARTNERS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>2929 ARCH STREET, 27TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>PHILADELPHIA</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-09-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18024</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1968371</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect By Partnership</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-09-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3114</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>339102</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect By Partnership</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.75</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2010-08-26</value>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2020-08-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Heritage Commerce Corp - Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2145000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2145000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect by Partnership</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Standard Employee Option - NSO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.16</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-06-16</value>
            </exerciseDate>
            <expirationDate>
                <value>2021-06-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Standard Employee Option - NSO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.39</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2012-05-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2022-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Standard Employee Option - NSO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2013-04-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2023-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Standard Employee Option - NSO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.07</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2014-02-27</value>
            </exerciseDate>
            <expirationDate>
                <value>2024-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Transaction of Patriot Financial Partners, L.P.</footnote>
        <footnote id="F2">The securities are held by Patriot Financial Partners, L.P. (the &quot;Patriot Fund&quot;) and Patriot Financial Partners Parallel, L.P. (the &quot;Patriot Parallel Fund,&quot; together with the Patriot Fund, the &quot;Funds&quot;). Patriot Financial Partners, GP, L.P. (&quot;Patriot GP&quot;) is a general partner of each of the Funds, and Patriot Financial Partners, GP, LLC (&quot;Patriot LLC&quot;) is a general partner of Patriot GP. In addition, W. Kirk Wycoff is a general partner of the Funds and Patriot GP and a member of Patriot LLC. Accordingly, securities owned by the Funds may be regarded as being beneficially owned by Patriot GP, Patriot LLC and W. Kirk Wycoff. Mr. Wycoff disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that he is a beneficial owner of such securities for the purposes of Section 16.</footnote>
        <footnote id="F3">Transaction of Patriot Financial Partners Parallel, L.P.</footnote>
        <footnote id="F4">The Series C Preferred Stock is automatically convertible following the subsequent transfer of the Series C Preferred stock to a transferee not affiliated with the holder in a widely dispersed offering.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Debbie Reuter as Attorney in fact for Kirk Wycoff</signatureName>
        <signatureDate>2016-09-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
