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Stock-Based Compensation Expense - Additional Information (Detail)	12 Months Ended			32 Months Ended
	Dec. 31, 2025 USD ($) group $ / shares shares	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2025 USD ($) group shares	May 03, 2023 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of groups within the employee population \| group	2			2
Estimated forfeiture rate for unvested options for senior management	11.00%			11.00%
Estimated forfeiture rate for unvested options for all non-senior management	13.00%			13.00%
Increase in compensation expense due to revised estimated forfeiture rates	$ 4,789,000	$ 1,832,000	$ 234,000
Weighted-average grant-date fair values of stock options granted \| $ / shares	$ 12.14	$ 14.89	$ 17.76
Total intrinsic values of stock options exercised	$ 4,179,000	$ 4,626,000	$ 6,227,000
Total fair values of stock options vested	24,197,000	29,309,000	34,751,000
Total unrecognized compensation expense related to non-vested stock options	$ 48,015,000			$ 48,015,000
Recognition period for unrecognized compensation expense	1 year 6 months
Stock-based compensation expense	$ 48,517,000	52,443,000	54,768,000
Income tax benefit recognized related to stock-based compensation expense	6,820,000	8,387,000	8,442,000
Compensation expense capitalized	$ 0	$ 0	$ 0	$ 0
Cognex Corporation 2023 Stock Option And Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized \| shares	9,684,542			9,684,542	8,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized \| shares				1,584,542
Cognex Corporation 2021 And 2007 Stock Option And Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans \| shares					10,610,800
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans \| shares	4,006,000			4,006,000
Expiration period of stock option plan	10 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, weighted-average exercise price \| $ / shares	$ 32.14	$ 39.05	$ 44.86
Vested (in shares) \| shares	0	0	0
Granted \| shares	184,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash used to fund tax payments	$ 6,877,000	$ 5,017,000	$ 7,836,000
Income tax benefit recognized related to stock-based compensation expense	$ (9,250,000)	$ (7,401,000)	$ (3,229,000)
Granted, weighted-average exercise price \| $ / shares		$ 38.90	$ 46.14
Vested (in shares) \| shares	731,000	429,000	521,000
Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Requisite Service Period	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Measurement Period	3 years
Minimum [Member] \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	3 years
Minimum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	3 years
Minimum [Member] \| Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Achievement Range, Percentage	0.00%
Maximum [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	5 years
Maximum [Member] \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	3 years
Maximum [Member] \| Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Achievement Range, Percentage	120.00%