Stock-Based Compensation Expense - Additional Information (Detail)	12 Months Ended			20 Months Ended
	Dec. 31, 2024 USD ($) group $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2024 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	3			3
Estimated forfeiture rate for unvested options for senior management	8.00%			8.00%
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	$ 1,832,000	$ 234,000	$ 1,536,000
Weighted-average grant-date fair values of stock options granted | $ / shares	$ 14.89	$ 17.76	$ 21.39
Total intrinsic values of stock options exercised	$ 4,626,000	$ 6,227,000	$ 8,424,000
Total fair values of stock options vested	29,309,000	34,751,000	41,497,000
Total unrecognized compensation expense related to non-vested stock options	$ 51,147,000			$ 51,147,000
Recognition period for unrecognized compensation expense	1 year 6 months
Stock-based compensation expense	$ 52,443,000	54,768,000	54,505,000
Income tax benefit recognized related to stock-based compensation expense	8,387,000	8,442,000	9,540,000
Compensation expense capitalized	$ 0	$ 0	$ 0	$ 0
Estimated Forfeiture Rate for Unvested Options for CEO	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	9,242,995			9,242,995	8,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized | shares				1,142,995
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	6,458,000			6,458,000
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	$ 39.05	$ 44.86	$ 62.49
Vested (in shares) | shares	0	0	0
Granted | shares	55,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash used to fund tax payments	$ 5,017,000	$ 7,836,000	$ 2,406,000
Income tax benefit recognized related to stock-based compensation expense	$ (7,401,000)	$ (3,229,000)	$ (1,049,000)
Granted, weighted-average exercise price | $ / shares		$ 46.14	$ 58.06
Vested (in shares) | shares	429,000	521,000	192,000
Minimum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	4 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
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] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans	4 years