Represents the amount of increase (decrease) in finance lease assets.

No definition available.

Name:	cohu_IncreaseDecreaseInFinanceLeaseAssets
Namespace Prefix:	cohu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of increase (decrease) in finance lease liability.

+ References

No definition available.

+ Details

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Namespace Prefix:	cohu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in operating lease right-of-use assetS.

+ References

No definition available.

+ Details

Name:	cohu_IncreaseDecreaseInOperatingLeaseRightOfUseAssets
Namespace Prefix:	cohu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- Definition

Amount of accumulated amortization of right-of-use asset from finance lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (a)
-SubTopic 20
-Topic 842
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
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-Subparagraph (a)
-SubTopic 20
-Topic 842
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

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

- Definition

Amount of increase (decrease) in obligation for operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-Publisher FASB
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480060/805-50-25-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

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

- Details

Name:	us-gaap_LeaseContractualTermAxis=cohu_LeasedFacilityInMalaysiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
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Note 12 - Leases (Details Textual) $ in Thousands, RM in Millions		3 Months Ended		12 Months Ended
	Dec. 30, 2024 USD ($)	Mar. 30, 2024 USD ($)	Mar. 30, 2024 MYR (RM)	Dec. 28, 2024 USD ($)	Dec. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 28, 2024 USD ($)
Lessee, Operating Lease, Renewal Term (Year)				25 years
Finance Lease, Right-of-Use Asset, Accumulated Amortization				$ 400	$ 300
Increase (Decrease) in Operating Lease Liability				5,903	7,454	$ 5,258
Increase (Decrease) in Operating Lease, Right-of-Use Assets				(5,812)	(7,656)	$ (5,139)
Operating lease assets				13,908	$ 16,778
Finance Lease, Liability				8,421
Leased Facility in Malaysia [Member]
Payments to Acquire Productive Assets \| RM			RM 41.8
Increase (Decrease) in Operating Lease Liability		$ 400
Increase (Decrease) in Operating Lease, Right-of-Use Assets		(400)
Increase (Decrease) in Finance Lease Assets	$ (9,500)	8,800
Increase (Decrease) in Finance Lease Liability	$ (8,400)	$ 7,900
Operating lease assets							$ 9,500
Finance Lease, Liability				$ 8,400
Minimum [Member]
Lessee, Lease, Remaining Term of Contract (Year)				1 year
Maximum [Member]
Lessee, Lease, Remaining Term of Contract (Year)				33 years