Note 7 - Business Acquisitions - Preliminary Allocation of Intangible Assets (Details) - USD ($) $ in Millions	Oct. 02, 2023	Jan. 30, 2023
MCT Worldwide, LLC [Member]
Intangible assets, estimated fair value		$ 12.0
MCT Worldwide, LLC [Member] \| Developed Technology Rights [Member]
Finite-lived intangible assets, estimated fair value		$ 7.5
Finite-lived intangible assets, average useful life (Year)		7 years
MCT Worldwide, LLC [Member] \| Customer Relationships [Member]
Finite-lived intangible assets, estimated fair value		$ 4.0
Finite-lived intangible assets, average useful life (Year)		10 years
MCT Worldwide, LLC [Member] \| Order or Production Backlog [Member]
Finite-lived intangible assets, estimated fair value		$ 0.5
Finite-lived intangible assets, average useful life (Year)		6 months
Equiptest Engineering Pte Ltd. (“EQT”) [Member]
Intangible assets, estimated fair value	$ 34.5
Equiptest Engineering Pte Ltd. (“EQT”) [Member] \| Developed Technology Rights [Member]
Finite-lived intangible assets, estimated fair value	$ 20.6
Finite-lived intangible assets, average useful life (Year)	8 years
Equiptest Engineering Pte Ltd. (“EQT”) [Member] \| Customer Relationships [Member]
Finite-lived intangible assets, estimated fair value	$ 12.9
Finite-lived intangible assets, average useful life (Year)	10 years
Equiptest Engineering Pte Ltd. (“EQT”) [Member] \| Order or Production Backlog [Member]
Finite-lived intangible assets, estimated fair value	$ 0.1
Finite-lived intangible assets, average useful life (Year)	1 year
Equiptest Engineering Pte Ltd. (“EQT”) [Member] \| Trademarks and Trade Names [Member]
Finite-lived intangible assets, estimated fair value	$ 0.9
Finite-lived intangible assets, average useful life (Year)	5 years

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with a finite or indefinite life, from an acquisition.

No definition available.

+ Details

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

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 985
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481283/985-20-50-2

+ Details

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

- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-1

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Details

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Data Type:	na
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- Details

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Data Type:	na
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- Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cohu_EquiptestEngineeringPteLtdEqtMember
Namespace Prefix:
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- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TrademarksAndTradeNamesMember
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