Payments to Acquire Business, before Working Capital Adjustment

No definition available.

Name:	cgnx_PaymentstoAcquireBusinessbeforeWorkingCapitalAdjustment
Namespace Prefix:	cgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow associated with other payments to acquire businesses including deposit on pending acquisitions and preacquisition costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

+ Details

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

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cgnx_EnShapeGmbHMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions (Details) € in Thousands, $ in Thousands				1 Months Ended
Acquisitions (Details) € in Thousands, $ in Thousands	Oct. 27, 2016 EUR (€)	Aug. 30, 2016 USD ($)	Aug. 30, 2016 EUR (€)	Oct. 31, 2016 USD ($)	Oct. 31, 2016 EUR (€)
AQSense, S.L.
Business Acquisition [Line Items]
Cash paid for acquisition at closing		$ 2,483	€ 2,200
Subsequent Event \| AQSense, S.L.
Business Acquisition [Line Items]
Working capital adjustment				$ 36	€ 32
Acquisition price, including capital adjustment				$ 2,519	€ 2,232
Useful life of intangible assets acquired				5 years	5 years
Subsequent Event \| EnShape GmbH
Business Acquisition [Line Items]
Acquisition price, including capital adjustment	€ 7,000