Summary of Significant Accounting Policies	9 Months Ended
Oct. 02, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies As permitted by the rules of the Securities and Exchange Commission applicable to Quarterly Reports on Form 10-Q, these notes are condensed and do not contain all disclosures required by generally accepted accounting principles (GAAP). The Company has provided expanded disclosures related to its revenue recognition accounting policy in this quarterly report on Form 10-Q. Reference should be made to the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 for a full description of significant accounting policies. In the opinion of the management of Cognex Corporation (the “Company”), the accompanying consolidated unaudited financial statements contain all adjustments, consisting of normal, recurring adjustments and financial statement reclassifications, including those related to the disposition of a business (more fully described in Note 14), necessary to present fairly the Company’s financial position as of October 2, 2016, and the results of its operations for the three-month and nine-month periods ended October 2, 2016 and October 4, 2015, and changes in shareholders’ equity, comprehensive income, and cash flows for the periods presented. The results disclosed in the Consolidated Statements of Operations for the three-month and nine-month periods ended October 2, 2016 are not necessarily indicative of the results to be expected for the full year. On July 6, 2015, the Company completed the sale of its Surface Inspection Systems Division (SISD). The financial results of SISD are reported as a discontinued operation for all periods presented. Revenue Recognition In order to recognize revenue, the Company requires that a signed customer contract or purchase order is received, the fee from the arrangement is fixed or determinable, and the collection of the resulting receivable is probable. Assuming that these criteria have been met, product revenue is generally recognized upon delivery, revenue from maintenance and support programs is recognized ratably over the program period, and revenue from consulting and training services is recognized when the services have been provided. When customer-specified acceptance criteria exists that are substantive, product revenue is deferred, along with associated incremental direct costs, until these criteria have been met and any remaining performance obligations are inconsequential or perfunctory. For the majority of the Company’s revenue transactions, revenue recognition and invoicing both occur upon delivery. In certain circumstances, however, the agreement with the customer provides for invoicing terms which differ from revenue recognition criteria, resulting in either deferred revenue or unbilled revenue. Invoicing that precedes revenue recognition is common for various customers in the logistics industry where milestone billings are prevalent, resulting in deferred revenue. Conversely, the Company records unbilled revenue in connection with a material customer in the consumer electronics industry. For this arrangement, the Company recognizes revenue for all delivered products when the first production line that incorporates these products is validated, because at that point the remaining performance obligations are inconsequential or perfunctory. Invoicing for all delivered products occurs as the production lines incorporating those products are installed over a period of several weeks. The Company also has a technical support obligation related to this arrangement for which revenue is deferred and recognized over the support period of approximately six months. Certain customers are offered pricing discounts on current sales based upon purchasing volumes or preferred pricing arrangements, for which revenue is reported net of these discounts.

Summary of Significant Accounting Policies

As permitted by the rules of the Securities and Exchange Commission applicable to Quarterly Reports on Form 10-Q, these notes are condensed and do not contain all disclosures required by generally accepted accounting principles (GAAP). The Company has provided expanded disclosures related to its revenue recognition accounting policy in this quarterly report on Form 10-Q. Reference should be made to the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 for a full description of significant accounting policies.

In the opinion of the management of Cognex Corporation (the “Company”), the accompanying consolidated unaudited financial statements contain all adjustments, consisting of normal, recurring adjustments and financial statement reclassifications, including those related to the disposition of a business (more fully described in Note 14), necessary to present fairly the Company’s financial position as of October 2, 2016, and the results of its operations for the three-month and nine-month periods ended October 2, 2016 and October 4, 2015, and changes in shareholders’ equity, comprehensive income, and cash flows for the periods presented.

The results disclosed in the Consolidated Statements of Operations for the three-month and nine-month periods ended October 2, 2016 are not necessarily indicative of the results to be expected for the full year.

On July 6, 2015, the Company completed the sale of its Surface Inspection Systems Division (SISD). The financial results of SISD are reported as a discontinued operation for all periods presented.

Revenue Recognition

In order to recognize revenue, the Company requires that a signed customer contract or purchase order is received, the fee from the arrangement is fixed or determinable, and the collection of the resulting receivable is probable. Assuming that these criteria have been met, product revenue is generally recognized upon delivery, revenue from maintenance and support programs is recognized ratably over the program period, and revenue from consulting and training services is recognized when the services have been provided. When customer-specified acceptance criteria exists that are substantive, product revenue is deferred, along with associated incremental direct costs, until these criteria have been met and any remaining performance obligations are inconsequential or perfunctory.

For the majority of the Company’s revenue transactions, revenue recognition and invoicing both occur upon delivery. In certain circumstances, however, the agreement with the customer provides for invoicing terms which differ from revenue recognition criteria, resulting in either deferred revenue or unbilled revenue. Invoicing that precedes revenue recognition is common for various customers in the logistics industry where milestone billings are prevalent, resulting in deferred revenue. Conversely, the Company records unbilled revenue in connection with a material customer in the consumer electronics industry. For this arrangement, the Company recognizes revenue for all delivered products when the first production line that incorporates these products is validated, because at that point the remaining performance obligations are inconsequential or perfunctory. Invoicing for all delivered products occurs as the production lines incorporating those products are installed over a period of several weeks. The Company also has a technical support obligation related to this arrangement for which revenue is deferred and recognized over the support period of approximately six months.

Certain customers are offered pricing discounts on current sales based upon purchasing volumes or preferred pricing arrangements, for which revenue is reported net of these discounts.