Stock-Based Compensation Expense - Additional Information (Detail)	8 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) group shares	Dec. 31, 2023 USD ($) group $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares 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		$ 234,000	$ 1,536,000	$ 255,000
Weighted-average grant-date fair values of stock options granted | $ / shares		$ 17.76	$ 21.39	$ 33.79
Total intrinsic values of stock options exercised		$ 6,227,000	$ 8,424,000	$ 80,369,000
Total fair values of stock options vested		34,751,000	41,497,000	45,328,000
Total unrecognized compensation expense related to non-vested stock options	$ 58,489,000	$ 58,489,000
Recognition period for unrecognized compensation expense		1 year 11 months 1 day
Stock-based compensation expense		$ 54,768,000	54,505,000	43,774,000
Income tax benefit recognized related to stock-based compensation expense		8,442,000	9,540,000	6,764,000
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	8,443,492	8,443,492			8,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized | shares	343,492
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	7,978,000	7,978,000
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		$ 44.86	$ 62.49
Vested (in shares) | shares		0	0	0
Granted | shares		46,000		0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash used to fund tax payments		$ 7,836,000	$ 2,406,000	$ 568,000
Income tax benefit recognized related to stock-based compensation expense		$ (3,229,000)	$ (1,049,000)	$ 126,000
Granted, weighted-average exercise price | $ / shares			$ 58.06	$ 87.03
Vested (in shares) | shares		521,000	192,000	16,000
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