<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:ffd="http://xbrl.sec.gov/ffd/2025q4"
  xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <link:schemaRef
      xlink:href="https://xbrl.sec.gov/ffd/2025q4/ffd-2025q4.xsd"
      xlink:type="simple"/>
    <context id="rc">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <context id="offrl_1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <context id="offrl_2">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>2</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <context id="offrl_3">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>3</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <context id="offrl_4">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>4</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <context id="offrl_5">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000021535</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>5</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-02-11</startDate>
            <endDate>2026-02-11</endDate>
        </period>
    </context>
    <unit id="USD">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="pure">
        <measure>pure</measure>
    </unit>
    <ffd:FormTp contextRef="rc" id="ixv-420">S-3</ffd:FormTp>
    <ffd:SubmissnTp contextRef="rc" id="ixv-421">S-3ASR</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="rc" id="ixv-422">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="rc" id="ixv-423">0000021535</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-424">COHU INC</dei:EntityRegistrantName>
    <ffd:OfferingTableNa contextRef="rc" id="hiddenrcOfferingTableNa" xsi:nil="true"/>
    <ffd:OffsetTableNa contextRef="rc" id="hiddenrcOffsetTableNa">N/A</ffd:OffsetTableNa>
    <ffd:CombinedProspectusTableNa contextRef="rc" id="hiddenrcCombinedProspectusTableNa">N/A</ffd:CombinedProspectusTableNa>
    <ffd:FormTp contextRef="rc" id="ixv-488">S-3</ffd:FormTp>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-489">COHU INC</dei:EntityRegistrantName>
    <ffd:PrevslyPdFlg contextRef="offrl_1" id="ixv-490">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_1" id="ixv-491">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_1" id="ixv-492">Common Stock</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_1" id="ixv-493">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_1"
      decimals="7"
      id="ixv-494"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:PrevslyPdFlg contextRef="offrl_2" id="ixv-495">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_2" id="ixv-496">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_2" id="ixv-497">Preferred Stock</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_2" id="ixv-498">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_2"
      decimals="7"
      id="ixv-499"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:PrevslyPdFlg contextRef="offrl_3" id="ixv-500">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_3" id="ixv-501">Debt</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_3" id="ixv-502">Debt Securities</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_3" id="ixv-503">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_3"
      decimals="7"
      id="ixv-504"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:PrevslyPdFlg contextRef="offrl_4" id="ixv-505">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_4" id="ixv-506">Other</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_4" id="ixv-507">Warrants</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_4" id="ixv-508">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_4"
      decimals="7"
      id="ixv-509"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:PrevslyPdFlg contextRef="offrl_5" id="ixv-510">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="offrl_5" id="ixv-511">Other</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_5" id="ixv-512">Units</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="offrl_5" id="ixv-513">true</ffd:Rule457rFlg>
    <ffd:FeeRate
      contextRef="offrl_5"
      decimals="7"
      id="ixv-514"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:TtlOfferingAmt contextRef="rc" decimals="2" id="ixv-515" unitRef="USD">0.00</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt contextRef="rc" decimals="2" id="ixv-516" unitRef="USD">0.00</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt contextRef="rc" decimals="2" id="ixv-517" unitRef="USD">0.00</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt contextRef="rc" decimals="2" id="ixv-518" unitRef="USD">0.00</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="rc" decimals="2" id="ixv-519" unitRef="USD">0.00</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="offrl_1" id="ixv-520">An unspecified aggregate initial offering price or number of securities of each identified class is being registered as may from time to time be offered hereunder at indeterminate prices and as may be issued upon exercise, conversion or exchange of any securities registered hereunder. Separate consideration may or may not be received for securities that are issuable upon exercise, conversion or exchange of other securities or that are issued in units. In addition, securities registered hereunder may be sold either separately or as units comprised of one or more types of securities registered hereunder. In accordance with Rule 456(b) and Rule 457(r) under the Securities Act of 1933, as amended, the registrant is deferring payment of all of the registration fee and will pay any applicable registration fees on a 'pay as you go' basis. The registrant will calculate the registration fee applicable to an offer of securities hereunder based on the fee payment rate in effect on the date of such fee payment.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_2" id="ixv-521">See Note 1.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_3" id="ixv-522">See Note 1.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_4" id="ixv-523">See Note 1.</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="offrl_5" id="ixv-524">See Note 1.</ffd:OfferingNote>
</xbrl>
