<SEC-DOCUMENT>0001312548-12-000048.txt : 20121219
<SEC-HEADER>0001312548-12-000048.hdr.sgml : 20121219
<ACCEPTANCE-DATETIME>20121219185243
ACCESSION NUMBER:		0001312548-12-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20121217
FILED AS OF DATE:		20121219
DATE AS OF CHANGE:		20121219

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Murphy Michael R
		CENTRAL INDEX KEY:			0001323510

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51470
		FILM NUMBER:		121275506

	MAIL ADDRESS:	
		STREET 1:		C/O DISCOVERY GROUP I, LLC
		STREET 2:		191 N. WACKER DRIVE SUITE 1685
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Donoghue Daniel J
		CENTRAL INDEX KEY:			0001323511

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51470
		FILM NUMBER:		121275507

	MAIL ADDRESS:	
		STREET 1:		C/O DISCOVERY GROUP I, LLC
		STREET 2:		191 N. WACKER DRIVE SUITE 1685
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AtriCure, Inc.
		CENTRAL INDEX KEY:			0001323885
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				341940305
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6217 CENTRE PARK DRIVE
		CITY:			WEST CHESTER
		STATE:			OH
		ZIP:			45069
		BUSINESS PHONE:		513-755-4107

	MAIL ADDRESS:	
		STREET 1:		6217 CENTRE PARK DRIVE
		CITY:			WEST CHESTER
		STATE:			OH
		ZIP:			45069

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Discovery Group I, LLC
		CENTRAL INDEX KEY:			0001312548
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51470
		FILM NUMBER:		121275508

	BUSINESS ADDRESS:	
		STREET 1:		191 N. WACKER DRIVE SUITE 1685
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		(312) 265-96000

	MAIL ADDRESS:	
		STREET 1:		191 N. WACKER DRIVE SUITE 1685
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-12-17</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001323885</issuerCik>
        <issuerName>AtriCure, Inc.</issuerName>
        <issuerTradingSymbol>ATRC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001312548</rptOwnerCik>
            <rptOwnerName>Discovery Group I, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>191 N. WACKER DRIVE SUITE 1685</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001323511</rptOwnerCik>
            <rptOwnerName>Donoghue Daniel J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DISCOVERY GROUP I, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>191 N. WACKER DRIVE SUITE 1685</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001323510</rptOwnerCik>
            <rptOwnerName>Murphy Michael R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DISCOVERY GROUP I, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>191 N. WACKER DRIVE SUITE 1685</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-12-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.533</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1621334</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Pleiades Investment Partners - D</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Discovery Group I, LLC is an investment manager for Pleiades Investment Partners - D, L.P., which is a discretionary client of the reporting person, that owns the reported securities. The reporting person disclaims beneficial ownership of the reported securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $6.50 - $6.57. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected</footnote>
    </footnotes>

    <remarks>Michael R. Murphy and Daniel J. Donoghue are managing members of Discovery Group I, LLC, and each disclaims beneficial ownership of the reported</remarks>

    <ownerSignature>
        <signatureName>Michael R. Murphy, Managing Director</signatureName>
        <signatureDate>2012-12-19</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Daniel J. Donoghue</signatureName>
        <signatureDate>2012-12-19</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Michael R. Murphy</signatureName>
        <signatureDate>2012-12-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
