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Guarantees - Additional Information (Detail) | 9 Months Ended
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Sep. 29, 2013 Category
Guarantees [Abstract] |
Number of categories of letters of credit | 3

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- Definition Number of categories of guarantees. + References No definition available. + Details
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Namespace Prefix: | cgnx_
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Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_GuaranteesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration