XML 42 R53.htm IDEA: XBRL DOCUMENT v2.4.1.9
Stock-Based Compensation Expense - Additional Information (Detail) (USD $)
3 Months Ended
Apr. 05, 2015
group
Mar. 30, 2014
Dec. 31, 2014
Apr. 17, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common Stock, Par or Stated Value Per Share $ 0.002us-gaap_CommonStockParOrStatedValuePerShare   $ 0.002us-gaap_CommonStockParOrStatedValuePerShare  
Expected dividend yield 1.25%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate    
Groups within the employee population 2cgnx_NumberOfGroupsWithinEmployeePopulation      
Percentage of stock options granted to senior management 74.00%cgnx_PercentageOfStockOptionsGrantedToSeniorManagementExpectedToVest      
Percentage of stock options granted to all other employees 73.00%cgnx_PercentageOfStockOptionsGrantedToAllOtherEmployeesExpectedToVest      
Estimated annual forfeiture rate 10.00%cgnx_EstimatedForfeitureRateForUnvestedOptionsForSeniorManagement      
Estimated annual forfeiture rate for unvested options 11.00%cgnx_EstimatedForfeitureRateForUnvestedOptionsForAllNonSeniorManagement      
Increase (decrease) to compensation expense $ 461,000cgnx_IncreaseInCompensationExpenseDueToRevisedEstimatedForfeitureRates $ 288,000cgnx_IncreaseInCompensationExpenseDueToRevisedEstimatedForfeitureRates    
Weighted-average grant-date fair values, in dollars per share $ 14.34us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 15.34us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue    
Total intrinsic value 16,740,000cgnx_SharesBasedCompensationArrangementBySharesBasedPaymentAwardOptionsExercisableIntrinsicValue 8,933,000cgnx_SharesBasedCompensationArrangementBySharesBasedPaymentAwardOptionsExercisableIntrinsicValue    
Total fair values of stock options vest 13,523,000cgnx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedFairValue 8,361,000cgnx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedFairValue    
Unrecognized compensation expense 30,963,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized      
weighted average period to be recognized 2 years 1 month 5 days      
Recognized Period Costs Capitalized Amount $ 0cgnx_EmployeeServiceShareBasedCompensationRecognizedPeriodCostsCapitalizedAmount   $ 0cgnx_EmployeeServiceShareBasedCompensationRecognizedPeriodCostsCapitalizedAmount  
Stock Option And Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 4 years      
Expiration period from grant day 10 years      
General Stock Option Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 4 years      
Employee Stock Option        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares available for grant under stock option plans 7,823,929us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
     
Expiration period from grant day 10 years      
2015 Through Expected Life of Option        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected dividend yield 1.25%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= cgnx_TwoThousandFifteenThroughExpectedLifeOfOptionMember
     
Subsequent Event [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common Stock, Par or Stated Value Per Share       $ 0.002us-gaap_CommonStockParOrStatedValuePerShare
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Subsequent Event [Member] | Employee Stock Option        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
additional shares under Share-based Compensation Arrangement by Share-based Payment Award, Additional Number of Shares Available for Grant       2,000,000cgnx_AdditionalsharesunderSharebasedCompensationArrangementbySharebasedPaymentAwardAdditionalNumberofSharesAvailableforGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Common Stock, Par or Stated Value Per Share       $ 0.002us-gaap_CommonStockParOrStatedValuePerShare
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember