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Goodwill - Additional Information (Detail) | Oct. 04, 2012
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MVSD [Member] |
Goodwill [Line Items] |
Fair value in excess to carrying value | 208.00%
SISD [Member] |
Goodwill [Line Items] |
Fair value in excess to carrying value | 119.00%

X
- Definition Fair value in excess to carrying value. + References No definition available. + Details
Name: | cgnx_FairValueInExcessToCarryingValue
Namespace Prefix: | cgnx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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