Name:	cohu_LesseeLeasingArrangementsOperatingLeasesAdjustmentsAndProRataShareOfPropertyOperatingCosts
Namespace Prefix:	cohu_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the lessee operating lease arrangement number of renewal options.

No definition available.

Name:	cohu_LesseeLeasingArrangementsOperatingLeasesNumberOfRenewalOptions
Namespace Prefix:	cohu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the percentage area of the facility to be occupied.

No definition available.

Name:	cohu_PercentageOfFacilityToBeConsolidated
Namespace Prefix:	cohu_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The amortization period of the deferred gain in a sale leaseback transaction.

No definition available.

Name:	cohu_SaleLeasebackTransactionDeferredGainAmortizationPeriod
Namespace Prefix:	cohu_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The yearly payments due under the lease entered into in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84164451&loc=d3e36991-112694

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77913982&loc=d3e50796-112755

Name:	us-gaap_SaleLeasebackTransactionAnnualRentalPayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The portion of the deferred gain that was recognized in the current period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77907795&loc=d3e50609-112754

Name:	us-gaap_SaleLeasebackTransactionCurrentPeriodGainRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of the gain recorded in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller to be recognized in future periods.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=77913853&loc=d3e49567-112750

Name:	us-gaap_SaleLeasebackTransactionDeferredGainGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The portion of the gain that will be recorded as income or a reduction in rent expense in future periods less amounts recognized in the current period.

Name:	us-gaap_SaleLeasebackTransactionDeferredGainNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of cash inflow before closing and debt issuance costs received by a seller-lessee in a sale-leaseback recognized in investing activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51843-112757

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51831-112757

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 51
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51840-112757

Name:	us-gaap_SaleLeasebackTransactionGrossProceedsInvestingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of cash inflow after closing and debt issuance costs received by a seller-lessee in a sale-leaseback recognized in investing activities.