Stock-Based Compensation Expense - Stock-Based Compensation Expense (Detail) (USD $)
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12 Months Ended |
Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
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Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Period for Recognition |
1 year 6 months 30 days |
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Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |
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Stock-based compensation expense |
$ 15,158,000us-gaap_AllocatedShareBasedCompensationExpense |
$ 10,620,000us-gaap_AllocatedShareBasedCompensationExpense |
$ 8,520,000us-gaap_AllocatedShareBasedCompensationExpense |
Income tax benefit recognized related to stock-based compensation expense |
4,977,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense |
3,482,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense |
2,772,000us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense |
Compensation expense capitalized |
0cgnx_EmployeeServiceShareBasedCompensationRecognizedPeriodCostsCapitalizedAmount |
0cgnx_EmployeeServiceShareBasedCompensationRecognizedPeriodCostsCapitalizedAmount |
0cgnx_EmployeeServiceShareBasedCompensationRecognizedPeriodCostsCapitalizedAmount |
Product cost of revenue [Member] |
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Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |
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Stock-based compensation expense |
1,033,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ProductCostOfRevenueMember |
747,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ProductCostOfRevenueMember |
581,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ProductCostOfRevenueMember |
Service cost of revenue [Member] |
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Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |
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Stock-based compensation expense |
171,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ServiceCostOfRevenueMember |
177,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ServiceCostOfRevenueMember |
161,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_ServiceCostOfRevenueMember |
Research, development, and engineering expenses |
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Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |
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Stock-based compensation expense |
3,832,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = us-gaap_ResearchAndDevelopmentExpenseMember |
2,585,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = us-gaap_ResearchAndDevelopmentExpenseMember |
2,149,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = us-gaap_ResearchAndDevelopmentExpenseMember |
Selling, general, and administrative [Member] |
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Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |
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Stock-based compensation expense |
$ 10,122,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_SellingGeneralAndAdministrativeMember |
$ 7,111,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_SellingGeneralAndAdministrativeMember |
$ 5,629,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_IncomeStatementLocationAxis = cgnx_SellingGeneralAndAdministrativeMember |