Cognex (CGNX) 10-Q 30 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Oct. 01, 2017shares
Document And Entity Information [Abstract]
Entity Registrant Name	COGNEX CORP
Entity Central Index Key	851,205
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Oct. 1, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	86,586,599

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Income Statement [Abstract]
Revenue	$ 259,739	$ 147,952	$ 567,585	$ 391,431
Cost of revenue	62,360	32,749	128,056	88,930
Gross margin	197,379	115,203	439,529	302,501
Research, development, and engineering expenses	26,078	18,603	72,225	58,829
Selling, general, and administrative expenses	61,054	42,072	160,093	123,125
Operating income	110,247	54,528	207,211	120,547
Foreign currency gain (loss)	(127)	(607)	(574)	(377)
Investment income	2,475	2,047	6,625	4,631
Other income (expense)	(445)	374	(344)	803
Income from continuing operations before income tax expense	112,150	56,342	212,918	125,604
Income tax expense (benefit) on continuing operations	9,802	2,667	8,843	14,030
Net income from continuing operations	102,348	53,675	204,075	111,574
Net income from discontinued operations	0	0	0	(255)
Net Income	$ 102,348	$ 53,675	$ 204,075	$ 111,319
Basic earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	$ 1.18	$ 0.63	$ 2.36	$ 1.31
Net income (loss) from discontinued operations	0	0	0	0
Net income	1.18	0.63	2.36	1.31
Diluted earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	1.14	0.61	2.28	1.29
Net income (loss) from discontinued operations	0	0	0	(0.01)
Net income	$ 1.14	$ 0.61	$ 2.28	$ 1.28
Weighted-average common and common-equivalent shares outstanding:
Basic	86,617	85,460	86,526	85,167
Diluted	89,677	87,346	89,562	86,805
Cash dividends per common share	$ 0.085	$ 0.075	$ 0.245	$ 0.22

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 102,348	$ 53,675	$ 204,075	$ 111,319
Cash flow hedges:
Net unrealized gain (loss), net of tax of ($8) and $21 in the three-month periods and net of tax of ($5) and ($76) in the nine-month periods, respectively	(4)	(86)	(16)	(965)
Reclassification of net realized (gain) loss into current operations	(56)	241	(21)	427
Net change related to cash flow hedges	(60)	155	(37)	(538)
Available-for-sale investments:
Net unrealized gain (loss), net of tax of $41 and ($29) in the three-month periods and net of tax of $191 and $481 in the nine-month periods, respectively	419	40	1,237	2,672
Reclassification of net realized (gain) loss into current operations	(263)	(55)	(370)	(183)
Net change related to available-for-sale investments	156	(15)	867	2,489
Foreign currency translation adjustments:
Foreign currency translation adjustments, net of tax of $0 and $80 in the three-month periods and net of tax of $0 and $254 in the nine-month periods, respectively	5,753	1,125	18,497	3,739
Other comprehensive income (loss), net of tax	5,849	1,265	19,327	5,690
Total comprehensive income	$ 108,197	$ 54,940	$ 223,402	$ 117,009

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Statement of Comprehensive Income [Abstract]
Tax effect on cash flow hedges	$ (8)	$ 21	$ (5)	$ (76)
Tax effect of unrealized gain (loss) on available-for-sale investments	41	(29)	191	481
Tax effect of foreign currency translation adjustment	$ 0	$ 80	$ 0	$ 254

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Oct. 01, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 111,349,000	$ 79,641,000
Short-term investments	273,261,000	341,194,000
Accounts receivable, less reserves of $1,279 and $873 in 2017 and 2016, respectively	121,976,000	55,438,000
Unbilled revenue	51,612,000	2,217,000
Inventories	48,061,000	26,984,000
Prepaid expenses and other current assets	38,824,000	20,870,000
Total current assets	645,083,000	526,344,000
Long-term investments	386,501,000	324,335,000
Property, plant, and equipment, net	65,957,000	53,992,000
Goodwill	113,208,000	95,280,000
Intangible assets, net	14,427,000	8,312,000
Deferred income taxes	30,524,000	28,022,000
Other assets	2,817,000	2,319,000
Total assets	1,258,517,000	1,038,604,000
Current liabilities:
Accounts payable	30,331,000	9,830,000
Accrued expenses	53,070,000	42,539,000
Accrued income taxes	10,053,000	5,193,000
Deferred revenue and customer deposits	16,072,000	8,211,000
Total current liabilities	109,526,000	65,773,000
Reserve for income taxes	5,563,000	5,361,000
Other non-current liabilities	9,905,000	4,871,000
Total liabilities	124,994,000	76,005,000
Shareholders’ equity:
Common stock, $.002 par value – Authorized: 200,000 shares in 2017 and 2016, respectively, issued and outstanding: 86,587 and 85,939 shares in 2017 and 2016, respectively	173,000	172,000
Additional paid-in capital	443,132,000	375,030,000
Retained earnings	727,319,000	643,825,000
Accumulated other comprehensive loss, net of tax	(37,101,000)	(56,428,000)
Total shareholders’ equity	1,133,523,000	962,599,000
Total liabilities and shareholders' equity	$ 1,258,517,000	$ 1,038,604,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Reserves for accounts receivable	$ 1,279	$ 873
Common stock, par value	$ 0.002	$ 0.002
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	86,587,000	85,939,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016
Cash flows from operating activities:
Net income	$ 204,075	$ 111,319
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of discontinued business	0	255
Stock-based compensation expense	23,355	15,883
Depreciation of property, plant, and equipment	9,811	8,551
Amortization of intangible assets	2,539	2,581
Amortization of discounts or premiums on investments	188	288
Realized (gain) loss on sale of investments	(370)	(733)
Revaluation of contingent consideration	88	(463)
Change in deferred income taxes	(1,830)	(1,415)
Accounts receivable	(58,379)	(37,802)
Unbilled revenue	(46,010)	(9,986)
Inventories	(18,550)	10,780
Prepaid expenses and other current assets	(14,968)	(4,524)
Accounts payable	19,132	2,089
Accrued expenses	8,819	7,560
Accrued income taxes	3,233	(531)
Deferred revenue and customer deposits	7,060	4,071
Other	1,861	(1,265)
Net cash provided by operating activities	140,054	106,658
Cash flows from investing activities:
Purchases of investments	(415,508)	(598,955)
Maturities and sales of investments	428,076	529,207
Purchases of property, plant, and equipment	(20,044)	(10,491)
Cash paid for acquisition of businesses, net of cash acquired	(24,118)	(2,483)
Net cash provided by (used in) investing activities	(291)	(113)
Net cash provided by (used in) investing activities	(31,885)	(82,835)
Cash flows from financing activities:
Issuance of common stock under stock plans	44,750	23,091
Repurchase of common stock	(99,347)	(18,941)
Payment of dividends	(21,236)	(18,761)
Payment of contingent consideration	(1,926)	(337)
Net cash provided by (used in) financing activities	(77,759)	(14,948)
Effect of foreign exchange rate changes on cash and cash equivalents	1,298	295
Net change in cash and cash equivalents	31,708	9,170
Cash and cash equivalents at beginning of period	79,641	51,975
Cash and cash equivalents at end of period	$ 111,349	$ 61,145

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity - 9 months ended Oct. 01, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance, Shares at Dec. 31, 2016	85,939,000	85,939,000
Beginning Balance at Dec. 31, 2016	$ 962,599	$ 172	$ 375,030	$ 643,825	$ (56,428)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under stock plans, shares		1,732,000
Stockholders' Equity, Period Increase (Decrease)		$ 3
Issuance of common stock under stock plans	44,750		44,747
Stock Repurchased During Period, Shares		1,084,000
Stock repurchased during period, Value	99,347	$ 2		99,345
Stock-based compensation expense	23,355		23,355
Payment of dividends	(21,236)			(21,236)
Net income	204,075			204,075
Net unrealized gain (loss) on cash flow hedges, net of tax of ($5)	(16)				(16)
Reclassification of net realized loss on cash flow hedges	(21)				(21)
Net unrealized gain (loss) on available-for-sale investments, net of tax of $191	1,237				1,237
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(370)				(370)
Foreign currency translation adjustment, net of tax of $0	$ 18,497				18,497
Ending Balance, Shares at Oct. 01, 2017	86,587,000	86,587,000
Ending Balance at Oct. 01, 2017	$ 1,133,523	$ 173	$ 443,132	$ 727,319	$ (37,101)

Consolidated Statement of Shar9

Consolidated Statement of Shareholders' Equity (Parenthetical) $ in Thousands	9 Months Ended
	Oct. 01, 2017USD ($)
Statement of Stockholders' Equity [Abstract]
Tax effect on cash flow hedges	$ (5)
Tax effect of unrealized gain (loss) on available-for-sale investments	191
Foreign currency translation adjustment, tax	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Oct. 01, 2017
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). Cognex Corporation (the "Company") has provided new disclosures related to inventories and internal-use software 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, 2016 for a full description of significant accounting policies. In the opinion of the management of 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, necessary to present fairly the Company’s financial position as of October 1, 2017 , and the results of its operations for the three-month and nine-month periods ended October 1, 2017 and October 2, 2016 , 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 1, 2017 are not necessarily indicative of the results to be expected for the full year. Inventories On January 1, 2017, the Company adopted Accounting Standards Update (ASU) 2015-11 "Inventory - Simplifying the Measurement of Inventory." This Update requires companies to measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. This adoption did not have an impact on the Company's inventory value. Internal-use Software The Company accounts for the costs of computer software developed or obtained for internal use under Accounting Standards Codification 350-40 "Intangibles - Goodwill and Other, Internal-use Software." Internal-use software is software acquired, internally developed, or modified solely to meet the entity's internal needs, and during the software's development, no substantive plan exists to sell the software. The preliminary project stage includes conceptual formulation of design alternatives, determination of system requirements, vendor demonstrations, and final selection of vendors, and during this stage costs are expensed as incurred. The application development stage includes software configuration, coding, hardware installation, and testing. During this stage, certain costs are capitalized, including external direct costs of materials and services, as well as payroll and payroll-related costs for employees who are directly associated with the project, while certain costs are expensed as incurred, including training and data conversion costs. The post-implementation stage includes training and maintenance, and during this stage costs are expensed as incurred. Capitalization begins when both the preliminary project stage is completed and management commits to funding the project. Capitalization ceases at the point the project is substantially complete and ready for its intended use, that is, after all substantial testing is completed. Costs of specified upgrades and enhancements to internal-use software are capitalized if it is probable that those expenditures result in additional functionality. Capitalized costs are amortized on a straight line basis over the estimated useful life.

New Pronouncements

New Pronouncements	9 Months Ended
	Oct. 01, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
New Pronouncements	New Pronouncements Accounting Standards Update (ASU) 2014-09, “Revenue from Contracts with Customers” The amendments in ASU 2014-09 will supersede and replace all currently existing U.S. GAAP, including industry-specific revenue recognition guidance, with a single, principle-based revenue recognition framework. The concept guiding this new model is that revenue recognition will depict transfer of control to the customer in an amount that reflects consideration to which an entity expects to be entitled. The core principles supporting this framework include (1) identifying the contract with a customer, (2) identifying separate performance obligations within the contract, (3) determining the transaction price, (4) allocating the transaction price to the performance obligations, and (5) recognizing revenue. This new framework will require entities to apply significantly more judgment. This increase in management judgment will require expanded disclosure on estimation methods, inputs, and assumptions for revenue recognition. In March 2016, ASU 2016-08, "Principal versus Agent Considerations (Reporting Revenue Gross versus Net)," was issued, in April 2016, ASU 2016-10, "Identifying Performance Obligations and Licensing," was issued, in May 2016, ASU 2016-12, "Narrow-Scope Improvements and Practical Expedients," was issued, and in December 2016, ASU 2016-20, "Technical Corrections and Improvements," was issued. These Updates do not change the core principle of the guidance under ASU 2014-09, but rather provide implementation guidance. ASU 2015-14, "Deferral of the effective date," amended the effective date of ASU 2014-09 for public companies to annual reporting periods beginning after December 15, 2017. Early adoption is permitted, but only beginning after December 15, 2016. The Financial Accounting Standards Board may release additional implementation guidance in future periods. We expect to adopt this standard using the full retrospective method to present all periods reported on a consistent basis. Upon adoption, revenue for software-only products sold as part of multiple-deliverable arrangements will no longer be deferred when vendor-specific objective evidence of fair value does not exist for undelivered elements of the arrangement. This change will likely result in earlier recognition of revenue. In addition, we expect certain of the Company’s product accessory sales, which are currently reported on a net basis, to be reported on a gross basis as a result of applying the expanded guidance in the new standard related to principal versus agent considerations. This change will result in the Company reporting higher revenue and higher cost of revenue when these sales are reported on a gross basis, although the gross margin dollars will not change. Furthermore, for arrangements that include customer-specified acceptance criteria, we expect to recognize revenue when we can objectively determine that control has been transferred to the customer in accordance with the agreed-upon specifications in the contract, which may occur before formal customer acceptance. This change will primarily impact revenue recognition for arrangements in the logistics industry where certain customer solutions include installed ID products and will likely result in earlier recognition of revenue. We do not expect these changes to have a material impact on total revenue. As of the date of this report, we have completed a number of implementation activities including the update of the Company's revenue accounting policy, the identification of internal controls under the new standard, the review of a selected number of contracts, and the calculation of transition-period adjustments. We are currently in the process of drafting the disclosures to finalize the implementation of this standard. Accounting Standards Update (ASU) 2016-01, "Financial Instruments - Recognition and Measurement of Financial Assets and Financial Liabilities" ASU 2016-01 provides guidance related to certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The amendments in this Update affect all entities that hold financial assets or owe financial liabilities. This ASU requires equity investments (except those accounted under the equity method) to be measured at fair value with changes in fair value recognized in net income. However, an entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment. This ASU also eliminates the requirement for public companies to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet, and it requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. For public companies, the guidance in ASU 2016-01 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is not permitted except for certain amendments in this Update. Management does not expect ASU 2016-01 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2016-02, "Leases" ASU 2016-02 creates Topic 842, Leases. The objective of this Update is to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet, and disclosing key information about leasing arrangements. This ASU applies to any entity that enters into a lease, although lessees will see the most significant changes. The main difference between current U.S. GAAP and Topic 842 is the recognition of lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under current U.S. GAAP. Topic 842 distinguishes between finance leases and operating leases, which are substantially similar to the classification criteria for distinguishing between capital leases and operating leases under current U.S. GAAP. For public companies, the guidance in ASU 2016-02 is effective for annual periods beginning after December 15, 2018, and interim periods within those annual periods. This ASU should be applied using a modified retrospective approach. Management is in the process of evaluating the impact of this Update. Accounting Standards Update (ASU) 2016-13, "Financial Instruments - Measurement of Credit Losses" ASU 2016-13 applies to all reporting entities holding financial assets that are not accounted for at fair value through net income (debt securities). The amendments in this Update eliminate the probable initial recognition threshold to recognize a credit loss under current U.S. GAAP and, instead, reflect an entity’s current estimate of all expected credit losses. In addition, this Update broadens the information an entity must consider in developing the credit loss estimate, including the use of reasonable and supportable forecasted information. The amendments in this Update require that credit losses on available-for-sale debt securities be presented as an allowance rather than as a write-down and an entity will be able to record reversals of credit losses in current period net income. For public companies, the guidance in ASU 2016-13 is effective for annual periods beginning after December 15, 2019, and interim periods within those annual periods. This ASU should be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. Management does not expect ASU 2016-13 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2016-16, "Income Taxes - Intra-Entity Transfers of Assets Other than Inventory" ASU 2016-16 applies to all reporting entities with intra-entity transfers of assets other than inventory. The amendments in this Update allow the recognition of deferred income taxes for an intra-entity transfer of an asset other than inventory when the transfer occurs, as opposed to when the asset has been sold to an outside party under current U.S. GAAP. Two common examples of assets included in the scope of this Update are intellectual property and property, plant, and equipment. For public companies, the amendments in ASU 2016-16 are effective for annual reporting periods beginning after December 15, 2017, and interim reporting periods within those annual periods. Early adoption is permitted for all entities as of the beginning of an annual reporting period for which financial statements (interim or annual) have not been issued or made available for issuance. This ASU should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Management does not expect ASU 2016-16 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2017-01, "Business Combinations - Clarifying the Definition of a Business" ASU 2017-01 applies to all reporting entities that must determine whether they have acquired or sold a business. The amendments in this Update clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. For public companies, the amendments in ASU 2017-01 are effective for annual reporting periods beginning after December 15, 2017, and interim reporting periods within those annual periods. This ASU should be applied prospectively on or after the effective date and no disclosures are required at transition. Early adoption is permitted for transactions for which the acquisition date occurs before the issuance date or the effective date of the amendments in this Update, only when the transaction has not been reported in financial statements that have been issued. Management does not expect ASU 2017-01 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2017-04, "Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment" ASU 2017-04 applies to all reporting entities that have goodwill reported in their financial statements. The amendments in this Update eliminate Step 2 from the goodwill impairment test reducing the cost and complexity of evaluating goodwill for impairment. In computing the implied fair value of goodwill under Step 2, an entity had to perform procedures to determine the fair value at the impairment date of its assets and liabilities as would be required in a business combination. Instead, under the amendments in this Update, an entity should perform its goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. For public companies, the amendments in ASU 2017-04 are effective for the annual or any interim goodwill impairment tests for reporting periods beginning after December 15, 2019. This ASU should be applied prospectively and an entity is required to disclose the nature of and reason for the change in accounting principle upon transition. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. Management does not expect ASU 2017-04 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2017-08, "Receivables - Nonrefundable Fees and Other Costs - Premium Amortization on Purchased Callable Debt Securities " ASU 2017-08 applies to all reporting entities that hold investments in callable debt securities that have an amortized cost basis in excess of the amount that is repayable by the issuer at the earliest call date (that is, at a premium). The amendments in this Update shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. Under current GAAP, premiums and discounts on callable debt securities generally are amortized to the maturity date. If that callable debt security is subsequently called, the entity records a loss equal to the unamortized premium. The amendments in this Update more closely align the amortization period of premiums and discounts to expectations incorporated in market pricing on the underlying securities. For public companies, the amendments in ASU 2017-08 are effective for annual periods beginning after December 15, 2019 and interim reporting periods within annual years beginning after December 15, 2020. This ASU should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption, and, in the period of adoption, the entity is required to provide disclosures about the change in accounting principle. Early adoption is permitted, including adoption in an interim period. Management is in the process of evaluating the impact of this Update. Accounting Standards Update (ASU) 2017-09, "Compensation - Stock Compensation - Scope of Modification Accounting" ASU 2017-09 applies to all reporting entities that change the terms or conditions of a share-based payment award. Currently, the definition of the term modification is broad and its interpretation results in diversity in practice. The amendments in this Update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all the following are met: 1) the fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified, 2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified, and 3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. For public companies, the amendments in ASU 2017-09 are effective for annual reporting periods beginning after December 15, 2017, and interim reporting periods within those annual periods. Early adoption is permitted including adoption in an interim period, for reporting periods for which financial statements have not yet been issued. This ASU should be applied prospectively to an award modified on or after the adoption date. Management does not expect ASU 2017-09 to have a material impact on the Company's financial statements and disclosures. Accounting Standards Update (ASU) 2017-12, "Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities" ASU 2017-12 applies to all reporting entities that elect to apply hedge accounting. The hedge accounting requirements under current GAAP sometimes do not permit an entity to properly recognize the economic results of the hedging strategy in the financial statements, and they are difficult to understand and interpret. The amendments in this Update make certain targeted improvements to simplify the application of the hedge accounting guidance. Also, they better align the risk management activities and financial reporting for hedging relationships through changes to both 1) the designation and measurement guidance for qualifying hedging relationships and 2) the presentation of hedge results. For public companies, the amendments in ASU 2017-12 are effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods within those annual periods. Early adoption is permitted including adoption in any interim period after issuance of the Update. All transition requirements and elections should be applied to hedging relationships existing on the date of adoption. The entity should apply a cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the amendments in this Update. The amended presentation and disclosure guidance is required only prospectively. Management is in the process of evaluating the impact of this Update.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Oct. 01, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Financial Assets and Liabilities that are Measured at Fair Value on a Recurring Basis The following table summarizes the financial assets and liabilities required to be measured at fair value on a recurring basis as of October 1, 2017 (in thousands): Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Money market instruments $ 6,700 $ — $ — Corporate bonds — 311,509 — Treasury bills — 133,786 — Asset-backed securities — 106,909 — Euro liquidity fund — 52,312 — Sovereign bonds — 28,971 — Agency bonds — 13,245 — Municipal bonds — 13,030 — Economic hedge forward contracts — 13 — Liabilities: Economic hedge forward contracts — 13 — Contingent consideration liabilities — — 3,673 The Company’s money market instruments are reported at fair value based upon the daily market price for identical assets in active markets, and are therefore classified as Level 1. The Company’s debt securities and forward contracts are reported at fair value based upon model-driven valuations in which all significant inputs are observable or can be derived from or corroborated by observable market data for substantially the full term of the asset or liability, and are therefore classified as Level 2. Management is responsible for estimating the fair value of these financial assets and liabilities, and in doing so, considers valuations provided by a large, third-party pricing service. For debt securities, this service maintains regular contact with market makers, brokers, dealers, and analysts to gather information on market movement, direction, trends, and other specific data. They use this information to structure yield curves for various types of debt securities and arrive at the daily valuations. The Company's forward contracts are typically traded or executed in over-the-counter markets with a high degree of pricing transparency. The market participants are generally large commercial banks. The Company did not record an other-than-temporary impairment of these financial assets during the nine -month period ended October 1, 2017 . The Company's contingent consideration liabilities are reported at fair value based upon probability-adjusted present values of the consideration expected to be paid, using significant inputs that are not observable in the market, and are therefore classified as Level 3. Key assumptions used in these estimates include probability assessments with respect to the likelihood of achieving certain revenue milestones. The fair values of these contingent consideration liabilities were calculated using discount rates consistent with the level of risk of achievement, and are remeasured each reporting period with changes in fair value recorded in "Other income (expense)" on the Consolidated Statements of Operations. The following table summarizes the activity for the Company's liability measured at fair value using Level 3 inputs for the nine-month period ended October 1, 2017 (in thousands): Balance as of December 31, 2016 $ 4,173 Payment of EnShape contingent consideration (1,401 ) Payment of Manatee contingent consideration (525 ) Contingent consideration resulting from GVi acquisition 1,299 Fair value adjustment to Manatee contingent consideration (275 ) Fair value adjustment to Chiaro contingent consideration 185 Fair value adjustment to GVi contingent consideration 178 Foreign exchange rate changes 39 Balance as of October 1, 2017 $ 3,673 Non-financial Assets that are Measured at Fair Value on a Non-recurring Basis Non-financial assets such as property, plant and equipment, goodwill, and intangible assets are required to be measured at fair value only when an impairment loss is recognized. The Company did not record an impairment charge related to these assets during the nine -month period ended October 1, 2017 .

Cash, Cash Equivalents, and Inv

Cash, Cash Equivalents, and Investments	9 Months Ended
	Oct. 01, 2017
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Investments	Cash, Cash Equivalents, and Investments Cash, cash equivalents, and investments consisted of the following (in thousands): October 1, 2017 December 31, 2016 Cash $ 104,649 $ 77,307 Money market instruments 6,700 2,334 Cash and cash equivalents 111,349 79,641 Treasury bills 70,184 67,175 Corporate bonds 65,569 141,188 Euro liquidity fund 52,312 46,499 Asset-backed securities 47,840 69,614 Sovereign bonds 20,945 7,298 Municipal bonds 8,805 6,517 Agency bonds 7,606 2,903 Short-term investments 273,261 341,194 Corporate bonds 245,940 169,952 Treasury bills 63,602 92,280 Asset-backed securities 59,069 26,946 Sovereign bonds 8,026 23,585 Agency bonds 5,639 10,339 Municipal bonds 4,225 1,233 Long-term investments 386,501 324,335 $ 771,111 $ 745,170 Treasury bills consist of debt securities issued by the U.S. government; corporate bonds consist of debt securities issued by both domestic and foreign companies; the Euro liquidity fund invests in a portfolio of investment-grade bonds; asset-backed securities consist of debt securities collateralized by pools of receivables or loans with credit enhancement; sovereign bonds consist of direct debt issued by foreign governments; municipal bonds consist of debt securities issued by state and local government entities; and agency bonds consist of domestic or foreign obligations of government agencies and government sponsored enterprises that have government backing. The Euro liquidity fund is denominated in Euros, and the remaining securities are denominated in U.S. Dollars. The following table summarizes the Company’s available-for-sale investments as of October 1, 2017 (in thousands): Amortized Gross Gross Fair Value Short-term: Treasury bills $ 70,311 $ — $ (127 ) 70,184 Corporate bonds 65,484 91 (6 ) 65,569 Euro liquidity fund 51,929 383 — 52,312 Asset-backed securities 47,839 13 (12 ) 47,840 Sovereign bonds 20,974 5 (34 ) 20,945 Municipal bonds 8,805 — — 8,805 Agency bonds 7,600 6 — 7,606 Long-term: Corporate bonds 245,046 1,013 (119 ) 245,940 Treasury bills 63,704 — (102 ) 63,602 Asset-backed securities 59,038 76 (45 ) 59,069 Sovereign bonds 8,059 7 (40 ) 8,026 Agency bonds 5,630 9 — 5,639 Municipal bonds 4,219 9 (3 ) 4,225 $ 658,638 $ 1,612 $ (488 ) $ 659,762 The following table summarizes the Company’s gross unrealized losses and fair values for available-for-sale investments in an unrealized loss position as of October 1, 2017 (in thousands): Unrealized Loss Position For: Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Treasury bills $ 95,174 $ (150 ) $ 33,627 $ (79 ) $ 128,801 $ (229 ) Asset-backed securities 51,878 (55 ) 8,770 (2 ) 60,648 (57 ) Corporate bonds 20,106 (33 ) 15,154 (92 ) 35,260 (125 ) Sovereign bonds 2,495 (5 ) 19,854 (69 ) 22,349 (74 ) Municipal bonds 1,356 (3 ) — — 1,356 (3 ) $ 171,009 $ (246 ) $ 77,405 $ (242 ) $ 248,414 $ (488 ) As of October 1, 2017 , the Company did not recognize any other-than-temporary impairment of these investments. In its evaluation, management considered the type of security, the credit rating of the security, the length of time the security has been in a loss position, the size of the loss position, the Company's intent and ability to hold the security to expected recovery of value, and other meaningful information. The Company does not intend to sell, and is unlikely to be required to sell, any of these available-for-sale investments before their effective maturity or market price recovery. The Company recorded gross realized gains and gross realized losses on the sale of debt securities totaling $306,000 and $43,000 , respectively, during the three-month period ended October 1, 2017 and $55,000 and $0 , respectively, during the three-month period ended October 2, 2016 . The Company recorded gross realized gains and gross realized losses on the sale of debt securities totaling $449,000 and $79,000 , respectively, during the nine-month period ended October 1, 2017 and $280,000 and $97,000 , respectively, during the nine-month period ended October 2, 2016 . These gains and losses are included in "Investment income" on the Consolidated Statement of Operations. Prior to the sale of these securities, unrealized gains and losses for these debt securities, net of tax, are recorded in shareholders’ equity as other comprehensive income (loss). The following table presents the effective maturity dates of the Company’s available-for-sale investments as of October 1, 2017 (in thousands): <1 year 1-2 Years 2-3 Years 3-4 Years 4-5 Years 5-7 Years Total Corporate bonds $ 65,569 $ 109,918 $ 77,430 $ 17,223 $ 39,956 $ 1,413 $ 311,509 Treasury bills 70,184 63,602 — — — — 133,786 Asset-backed securities 47,840 35,502 16,075 — 2,328 5,164 106,909 Euro liquidity fund 52,312 — — — — — 52,312 Sovereign bonds 20,945 4,599 3,427 — — — 28,971 Agency bonds 7,606 2,719 — — 2,920 — 13,245 Municipal bonds 8,805 2,869 1,356 — — — 13,030 $ 273,261 $ 219,209 $ 98,288 $ 17,223 $ 45,204 $ 6,577 $ 659,762

Inventories

Inventories	9 Months Ended
	Oct. 01, 2017
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following (in thousands): October 1, 2017 December 31, 2016 Raw materials $ 23,146 $ 18,224 Work-in-process 1,631 2,760 Finished goods 23,284 6,000 $ 48,061 $ 26,984

Goodwill

Goodwill	9 Months Ended
	Oct. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The changes in the carrying value of goodwill were as follows (in thousands): Amount Balance as of December 31, 2016 $ 95,280 Acquisition of ViDi Systems S.A. 18,333 Acquisition of GVi Ventures, Inc. 1,476 Adjustment to EnShape goodwill (1,881 ) Balance as of October 1, 2017 $ 113,208 Refer to Note 15 to the Consolidated Financial Statements for further information regarding acquisitions.

Intangible Assets

Intangible Assets	9 Months Ended
	Oct. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets Amortized intangible assets consisted of the following (in thousands): Gross Carrying Value Accumulated Amortization Net Carrying Value Distribution networks $ 38,060 $ 38,060 $ — Completed technologies 13,687 3,571 10,116 Customer relationships 9,205 5,203 4,002 Non-compete agreements 370 61 309 Balance as of October 1, 2017 $ 61,322 $ 46,895 $ 14,427 Gross Carrying Value Accumulated Amortization Net Carrying Value Distribution networks $ 38,060 $ 37,422 $ 638 Completed technologies 8,003 2,098 5,905 Customer relationships 6,605 4,836 1,769 Balance as of December 31, 2016 $ 52,668 $ 44,356 $ 8,312 As of October 1, 2017, estimated future amortization expense related to intangible assets is as follows (in thousands): Year Ended December 31, Amount Remainder of fiscal 2017 $ 799 2018 3,196 2019 2,821 2020 2,305 2021 2,097 2022 1,691 Thereafter 1,518 $ 14,427

Warranty Obligations

Warranty Obligations	9 Months Ended
	Oct. 01, 2017
Product Warranties Disclosures [Abstract]
Warranty Obligations	Warranty Obligations The Company records the estimated cost of fulfilling product warranties at the time of sale based upon historical costs to fulfill claims. Obligations may also be recorded subsequent to the time of sale whenever specific events or circumstances impacting product quality become known that would not have been taken into account using historical data. While we engage in extensive product quality programs and processes, including actively monitoring and evaluating the quality of our component suppliers and third-party contract manufacturers, the Company’s warranty obligation is affected by product failure rates, material usage, and service delivery costs incurred in correcting a product failure. An adverse change in any of these factors may result in the need for additional warranty provisions. Warranty obligations are included in “Accrued expenses” on the Consolidated Balance Sheets. The changes in the warranty obligation were as follows (in thousands): Balance as of December 31, 2016 $ 4,335 Provisions for warranties issued during the period 2,322 Fulfillment of warranty obligations (2,323 ) Foreign exchange rate changes 545 Balance as of October 1, 2017 $ 4,879

Derivative Instruments

Derivative Instruments	9 Months Ended
	Oct. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments The Company’s foreign currency risk management strategy is principally designed to mitigate the potential financial impact of changes in the value of transactions and balances denominated in foreign currencies resulting from changes in foreign currency exchange rates. Currently, the Company enters into two types of hedges to manage this risk. The first are economic hedges which utilize foreign currency forward contracts with maturities of up to 45 days to manage the exposure to fluctuations in foreign currency exchange rates arising primarily from foreign-denominated receivables and payables. The gains and losses on these derivatives are intended to be offset by the changes in the fair value of the assets and liabilities being hedged. These economic hedges are not designated as hedging instruments for hedge accounting treatment. The second are cash flow hedges which utilize foreign currency forward contracts with maturities of up to 18 months to hedge specific forecasted transactions of the Company's foreign subsidiaries with the goal of protecting our budgeted revenues and expenses against foreign currency exchange rate changes compared to our budgeted rates. These cash flow hedges are designated as hedging instruments for hedge accounting treatment. The Company had the following outstanding forward contracts (in thousands): October 1, 2017 December 31, 2016 Currency Notional USD Notional USD Derivatives Designated as Hedging Instruments: Japanese Yen — $ — 342,500 $ 2,960 Hungarian Forint — — 39,000 130 Singapore Dollar — — 150 97 Derivatives Not Designated as Hedging Instruments: Japanese Yen 500,000 $ 4,440 650,000 $ 5,554 British Pound 1,720 2,294 1,350 1,658 Hungarian Forint 530,000 2,014 425,000 1,448 Korean Won 1,325,000 1,154 1,750,000 1,450 Singapore Dollar — — 1,350 929 Taiwanese Dollar 34,640 1,139 26,000 802 Swiss Franc 1,025 1,059 — — Information regarding the fair value of the outstanding forward contracts was as follows (in thousands): Asset Derivatives Liability Derivatives Balance Fair Value Balance Fair Value Sheet October 1, 2017 December 31, 2016 Sheet October 1, 2017 December 31, 2016 Derivatives Designated as Hedging Instruments: Cash flow hedge forward contracts Prepaid expenses and other current assets $ — $ 43 Accrued expenses $ — $ — Derivatives Not Designated as Hedging Instruments: Economic hedge forward contracts Prepaid expenses and other current assets $ 13 $ 1 Accrued expenses $ 13 $ 11 The following table presents the gross activity for all derivative assets and liabilities which were presented on a net basis on the Consolidated Balance Sheets due to the right of offset with each counterparty (in thousands): Asset Derivatives Liability Derivatives October 1, 2017 December 31, 2016 October 1, 2017 December 31, 2016 Gross amounts of recognized assets $ 13 $ 117 Gross amounts of recognized liabilities $ 13 $ 11 Gross amounts offset — (73 ) Gross amounts offset — — Net amount of assets presented $ 13 $ 44 Net amount of liabilities presented $ 13 $ 11 Information regarding the effect of derivative instruments on the consolidated financial statements was as follows (in thousands): Location in Financial Statements Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Derivatives Designated as Hedging Instruments: Gains (losses) recorded in shareholders' equity (effective portion) Accumulated other comprehensive income (loss), net of tax $ — $ (332 ) $ — $ (332 ) Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion) Revenue $ 56 $ (250 ) $ 10 $ (453 ) Research, development, and engineering expenses — 1 3 5 Selling, general, and administrative expenses — 8 8 21 Total gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations $ 56 $ (241 ) $ 21 $ (427 ) Derivatives Not Designated as Hedging Instruments: Gains (losses) recognized in current operations Foreign currency gain (loss) $ 43 $ (24 ) $ 139 $ (1,089 ) The following table provides the changes in accumulated other comprehensive income (loss), net of tax, related to derivative instruments (in thousands): Balance as of December 31, 2016 $ 37 Net unrealized loss on cash flow hedges (16 ) Reclassification of net realized gain on cash flow hedges into current operations (21 ) Balance as of October 1, 2017 $ — Net gains expected to be reclassified from accumulated other comprehensive income (loss), net of tax, into current operations within the next twelve months are $0 .

Stock-Based Compensation Expens

Stock-Based Compensation Expense	9 Months Ended
	Oct. 01, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense	Stock-Based Compensation Expense The Company’s share-based payments that result in compensation expense consist of stock option grants and restricted stock awards. As of October 1, 2017 , the Company had 6,183,376 shares available for grant. Stock options are granted with an exercise price equal to the market value of the Company’s common stock at the grant date and generally vest over four years based upon continuous service and expire ten years from the grant date. Restricted stock awards are granted with an exercise price equal to the market value of the Company's common stock at the time of grant. Conditions of the award may be based on continuing employment and/or achievement of pre-established performance goals and objectives. Vesting for performance-based restricted stock awards and time-based restricted stock awards must generally be at least one year and three years, respectively, but vesting may occur incrementally over the three-year period. The following table summarizes the Company’s stock option activity for the nine -month period ended October 1, 2017 : Shares (in thousands) Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2016 6,433 $ 32.16 Granted 1,980 77.87 Exercised (1,731 ) 25.85 Forfeited or expired (84 ) 45.57 Outstanding as of October 1, 2017 6,598 $ 47.36 7.77 $ 415,030 Exercisable as of October 1, 2017 1,707 $ 27.96 5.68 $ 140,559 Options vested or expected to vest as of October 1, 2017 (1) 5,795 $ 45.86 7.63 $ 373,276 (1) In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest are calculated by applying an estimated forfeiture rate to the unvested options. The fair values of stock options granted in each period presented were estimated using the following weighted-average assumptions: Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Risk-free rate 2.4 % 1.7 % 2.4 % 1.7 % Expected dividend yield 0.39 % 0.84 % 0.39 % 0.84 % Expected volatility 41 % 41 % 41 % 41 % Expected term (in years) 5.1 5.5 5.3 5.5 Risk-free rate The risk-free rate was based upon a treasury instrument whose term was consistent with the contractual term of the option. Expected dividend yield Generally, the current dividend yield is calculated by annualizing the cash dividend declared by the Company’s Board of Directors and dividing that result by the closing stock price on the grant date. Expected volatility The expected volatility was based upon a combination of historical volatility of the Company’s common stock over the contractual term of the option and implied volatility for traded options of the Company’s stock. Expected term The expected term was derived from the binomial lattice model from the impact of events that trigger exercises over time. The Company stratifies its employee population into two groups: one consisting of senior management and another consisting of all other employees. The Company currently expects that approximately 75% of its stock options granted to senior management and 72% of its options granted to all other employees will actually vest. Therefore, the Company currently applies an estimated annual forfeiture rate of 10% to all unvested options for senior management and a rate of 12% for all other employees. The Company revised its estimated forfeiture rate in the first quarter of 2017, resulting in a decrease to compensation expense of $673,000 . The Company also revised its estimated forfeiture rate in the first quarter of 2016, resulting in an increase to compensation expense of $334,000 . The weighted-average grant-date fair values of stock options granted during the three-month periods ended October 1, 2017 and October 2, 2016 were $29.59 and $12.34 , respectively. The weighted-average grant-date fair values of stock options granted during the nine-month periods ended October 1, 2017 and October 2, 2016 were $29.94 and $12.25 , respectively. The total intrinsic values of stock options exercised for the three-month periods ended October 1, 2017 and October 2, 2016 were $28,462,000 and $23,139,000 , respectively. The total intrinsic values of stock options exercised for the nine-month periods ended October 1, 2017 and October 2, 2016 were $100,913,000 and $32,514,000 , respectively. The total fair values of stock options vested for the three-month periods ended October 1, 2017 and October 2, 2016 were $844,000 and $679,000 , respectively. The total fair values of stock options vested for the nine-month periods ended October 1, 2017 and October 2, 2016 were $19,557,000 and $16,724,000 , respectively. As of October 1, 2017 , total unrecognized compensation expense related to non-vested stock options was $41,354,000 , which is expected to be recognized over a weighted-average period of 1.67 years. The following table summarizes the Company's restricted stock activity for the nine-month period ended October 1, 2017 : Shares (in thousands) Weighted-Average Grant Fair Value Aggregate Intrinsic Value (in thousands)(1) Nonvested as of December 31, 2016 20 $ 34.05 Granted — — Vested (10 ) 34.05 825 Forfeited or expired — — Nonvested as of October 1, 2017 10 $ 34.05 $ 1,103 (1) Fair market value as of April 22, 2017 for vested shares, and as of October 1, 2017 for nonvested shares. The fair values of restricted stock awards granted were determined based upon the market value of the Company's common stock at the time of grant. The initial cost is then amortized over the period of vesting until the restrictions lapse. These restricted shares will be fully vested in 2018. Participants are entitled to dividends on restricted stock awards, but only receive those amounts if the shares vest. The sale or transfer of these shares is restricted during the vesting period. The total stock-based compensation expense and the related income tax benefit recognized for the three-month period ended October 1, 2017 were $8,026,000 and $2,639,000 , respectively, and for the three-month period ended October 2, 2016 were $4,622,000 and $1,520,000 , respectively. The total stock-based compensation expense and the related income tax benefit recognized for the nine-month period ended October 1, 2017 were $23,355,000 and $7,661,000 , respectively, and for the nine-month period ended October 2, 2016 were $15,883,000 and $5,210,000 , respectively. No compensation expense was capitalized as of October 1, 2017 or December 31, 2016 . The following table presents the stock-based compensation expense by caption for each period presented on the Consolidated Statements of Operations (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Cost of revenue $ 520 $ 273 $ 1,404 $ 795 Research, development, and engineering 2,765 1,366 8,090 4,942 Selling, general, and administrative 4,741 2,983 13,861 10,146 $ 8,026 $ 4,622 $ 23,355 $ 15,883

Stock Repurchase Program

Stock Repurchase Program	9 Months Ended
	Oct. 01, 2017
Equity [Abstract]
Stock Repurchase Program	Stock Repurchase Program In November 2015, the Company's Board of Directors authorized the repurchase of $100,000,000 of the Company's common stock. As of October 1, 2017, the Company had repurchased 1,335,000 shares at a cost of $100,000,000 under this program, including 796,000 shares at a cost of $68,915,000 for the nine-month period ended October 1, 2017. In April 2017, the Company's Board of Directors authorized the repurchase of an additional $100,000,000 of the Company's common stock. Purchases under this April 2017 program commenced during the third quarter of 2017. As of October 1, 2017, the Company had repurchased 288,000 shares at a cost of $30,432,000 under this program. The Company may repurchase shares under this program in future periods depending upon a variety of factors, including, among other things, the impact of dilution from employee stock options, stock price, share availability, and cash requirements.

Taxes

Taxes	9 Months Ended
	Oct. 01, 2017
Income Tax Disclosure [Abstract]
Taxes	Taxes A reconciliation of the United States federal statutory corporate tax rate to the Company’s income tax expense on continuing operations, or effective tax rate, was as follows: Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Income tax provision at federal statutory corporate tax rate 35 % 35 % 35 % 35 % State income taxes, net of federal benefit 1 % 1 % 1 % 1 % Foreign tax rate differential (18 )% (17 )% (18 )% (17 )% Tax credit (1 )% (1 )% (1 )% (1 )% Discrete tax benefit related to stock option exercises (7 )% (11 )% (13 )% (6 )% Other discrete tax events (2 )% (2 )% (1 )% (1 )% Other 1 % — % 1 % — % Income tax provision on continuing operations 9 % 5 % 4 % 11 % The majority of income earned outside of the United States is permanently reinvested to provide funds for international expansion. The Company is tax resident in numerous jurisdictions around the world and has identified its major jurisdictions as the United States, Ireland, and China. The statutory tax rate is 12.5% in Ireland and 25% in China, compared to the U.S. federal statutory corporate tax rate of 35% . International rights to certain of the Company's intellectual property are held by a subsidiary whose legal jurisdiction does not tax this income, resulting in a foreign effective tax rate that is lower than the above mentioned statutory rates. These differences resulted in a decrease in the effective tax rate by 18 percentage points for the three-month and nine -month periods ended October 1, 2017 , and a decrease in the effective tax rate by 17% percentage points for the three-month and nine-month periods ended October 2, 2016 . The excess tax benefit arising from the difference between the deduction for tax purposes and the compensation cost recognized for financial reporting purposes from stock option exercises resulted in a decrease of the effective tax rate by 7 and 11 percentage points for the three-month periods ended October 1, 2017 and October 2, 2016 , respectively, and a decrease of the effective tax rate by 13 and 6 percentage points for the nine -month periods ended October 1, 2017 and October 2, 2016 , respectively. During the nine -month period ended October 1, 2017 , the Company recorded a $201,000 increase in reserves for income taxes, net of deferred tax benefit. Estimated interest and penalties included in these amounts totaled $22,000 for the nine -month period ended October 1, 2017 . The Company’s reserve for income taxes, including gross interest and penalties, was $6,591,000 as of October 1, 2017 , which included $5,563,000 classified as a non-current liability and $1,028,000 recorded as a reduction to non-current deferred tax assets. The amount of gross interest and penalties included in these balances was $701,000 . If the Company’s tax positions were sustained or the statutes of limitations related to certain positions expired, these reserves would be released and income tax expense would be reduced in a future period. As a result of the expiration of certain statutes of limitations, there is a potential that a portion of these reserves could be released, which would decrease income tax expense by approximately $1,000,000 to $1,200,000 over the next twelve months. The Company has defined its major tax jurisdictions as the United States, Ireland, and China, and within the United States, Massachusetts. Within the United States, the tax years 2014 through 2016 remain open to examination by the Internal Revenue Service and various state tax authorities. The tax years 2013 through 2016 remain open to examination by various taxing authorities in other jurisdictions in which the Company operates.

Weighted-Average Shares

Weighted-Average Shares	9 Months Ended
	Oct. 01, 2017
Earnings Per Share [Abstract]
Weighted-Average Shares	Weighted-Average Shares Weighted-average shares were calculated as follows (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Basic weighted-average common shares outstanding 86,617 85,460 86,526 85,167 Effect of dilutive stock options 3,060 1,886 3,036 1,638 Weighted-average common and common-equivalent shares outstanding 89,677 87,346 89,562 86,805 Stock options to purchase 233,081 and 1,554,129 shares of common stock, on a weighted-average basis, were outstanding during the three-month and nine-month periods ended October 1, 2017, respectively, and 491,375 and 3,641,279 for the same periods in 2016, but were not included in the calculation of dilutive net income per share because they were anti-dilutive.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Oct. 01, 2017
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations On July 6, 2015, the Company completed the sale of its Surface Inspection Systems Division (SISD). A binding arbitration was concluded in the second quarter of 2016 with respect to certain product performance claims made by an SISD customer, for which the Company remained responsible under the indemnity provisions of the sale transaction. In that proceeding, the tribunal ordered the Company to pay the customer approximately $326,000 , primarily representing a refund of the product purchase price. The tribunal also ordered the customer to pay the Company approximately $45,000 , primarily representing reimbursement of legal fees. The net settlement of $281,000 was recorded in discontinued operations in the second quarter of 2016, along with $123,000 of legal fees. The tax benefit related to this expense was $149,000 , resulting in a net loss from discontinued operations of $255,000 . The losses included in discontinued operations were as follows (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Operating income from discontinued operations $ — $ — $ — $ — Gain (loss) on sale of discontinued operations — — — (404 ) Income (loss) from discontinued operations before income tax expense (benefit) — — — (404 ) Income tax expense (benefit) on discontinued operations — — — (149 ) Net income (loss) from discontinued operations $ — $ — $ — $ (255 )

Acquisitions

Acquisitions	9 Months Ended
	Oct. 01, 2017
Business Combinations [Abstract]
Acquisitions	Acquisitions ViDi Systems S.A. On April 4, 2017, the Company acquired all of the outstanding shares of ViDi Systems, S.A. (ViDi), a privately-held vision software company based in Switzerland. This transaction has been accounted for as a business combination. The total purchase price of $23,015,000 included cash payment of $ 20,019,000 , with the remaining $ 2,996,000 recorded as a holdback to secure potential claims under the agreement. The holdback limitation period is 18 months, and therefore, this amount has been recorded in "Other non-current liabilities" on the Consolidated Balance Sheet. In addition, the Company entered into a special incentive payment tied to employment, which is not material, that the Company will record as compensation expense. Under this transaction, in addition to completed technologies, the Company acquired a team of software engineers that are expected to help the Company broaden the scope of applications that can be addressed with Cognex vision. ViDi's deep learning software uses artificial intelligence techniques to improve image analysis in applications where it is difficult to predict the full range of image variations that might be encountered. Using feedback, ViDi's software trains the system to distinguish between acceptable variations and defects. Assets acquired and liabilities assumed have been recorded at their estimated fair values as of the acquisition date. The purchase price was allocated as follows (in thousands): Cash $ 146 Accounts receivable 425 Prepaid expenses and other current assets 129 Property, plant, and equipment 40 Deferred income tax asset 620 Accounts payable (98 ) Accrued expenses (716 ) Deferred income tax liability (1,008 ) Non-compete agreement 370 Completed technologies 4,774 Goodwill 18,333 Purchase price $ 23,015 The non-compete agreement and completed technology are included in "Intangible assets" on the Consolidated Balance Sheet. The non-compete agreement will be amortized to research, development and engineering expenses over three years, and the completed technology will be amortized to cost of revenue over six years, both on a straight-line basis. The portion of the acquired goodwill deductible for tax purposes is $5,112,000 . Transaction costs were immaterial and were expensed as incurred. GVi Ventures, Inc. On April 12, 2017, the Company acquired selected assets and assumed selected liabilities of GVi Ventures, Inc., a privately-held maker of pre-configured vision solutions for common automotive applications based in the United States. This transaction has been accounted for as a business combination. The total purchase price of $5,368,000 included cash payment of $4,069,000 and contingent consideration valued at $1,299,000 as of the acquisition date. In addition, the Company entered into special incentive payments tied to employment, none of which are material, that the Company will record as compensation expense. The undiscounted potential outcomes related to the contingent consideration range from $0 to $3,500,000 based upon certain milestone revenue levels over the next five years. As of October 1, 2017 , the fair value of the contingent consideration was $1,477,000 , with $311,000 recorded in “Accrued expenses,” and $1,166,000 recorded in "Other non-current liabilities" on the Consolidated Balance Sheet. The contingent consideration is remeasured each reporting period with changes in fair value recorded in "Other income (expense)" on the Consolidated Statements of Operations. Under this transaction, in addition to customer relationships and completed technologies, the Company acquired a team of software engineers that are expected to develop new products and increase the Company's ability to serve large customers in the automotive industry. Assets acquired and liabilities assumed have been recorded at their estimated fair values as of the acquisition date. The purchase price was allocated as follows (in thousands): Accounts receivable $ 423 Inventories 120 Prepaid expenses and other current assets 1 Accounts payable (152 ) Accrued expenses (10 ) Completed technologies 910 Customer relationships 2,600 Goodwill 1,476 Purchase price $ 5,368 The customer relationships and completed technologies are included in "Intangible assets" on the Consolidated Balance Sheet. The customer relationships are being amort ized to selling, general, and administrative e xpenses over eight years, and the completed technologies are being amortized to cost of revenue over five years, both on a straigh t-line basis. A portion of t he acquired goodwill is deductible for tax purposes. Transaction costs were immaterial and were expensed as incurred. Pro-forma information for these acquisitions has not been presented because they are not material, either individually or in the aggregate.

Subsequent Events

Subsequent Events	9 Months Ended
	Oct. 01, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 30, 2017, the Company’s Board of Directors declared a cash dividend of $0.09 per share. The dividend is payable December 1, 2017 to all shareholders of record as of the close of business on November 17, 2017 . In addition, on October 30, 2017, the Company's Board of Directors declared a two -for-one split of the Company's common stock. The split will be effected in the form of a stock dividend, payable on December 1, 2017 to all shareholders of record as of the close of business on November 17, 2017.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Oct. 01, 2017
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table summarizes the financial assets and liabilities required to be measured at fair value on a recurring basis as of October 1, 2017 (in thousands): Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Assets: Money market instruments $ 6,700 $ — $ — Corporate bonds — 311,509 — Treasury bills — 133,786 — Asset-backed securities — 106,909 — Euro liquidity fund — 52,312 — Sovereign bonds — 28,971 — Agency bonds — 13,245 — Municipal bonds — 13,030 — Economic hedge forward contracts — 13 — Liabilities: Economic hedge forward contracts — 13 — Contingent consideration liabilities — — 3,673
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table summarizes the activity for the Company's liability measured at fair value using Level 3 inputs for the nine-month period ended October 1, 2017 (in thousands): Balance as of December 31, 2016 $ 4,173 Payment of EnShape contingent consideration (1,401 ) Payment of Manatee contingent consideration (525 ) Contingent consideration resulting from GVi acquisition 1,299 Fair value adjustment to Manatee contingent consideration (275 ) Fair value adjustment to Chiaro contingent consideration 185 Fair value adjustment to GVi contingent consideration 178 Foreign exchange rate changes 39 Balance as of October 1, 2017 $ 3,673

Cash, Cash Equivalents, and I27

Cash, Cash Equivalents, and Investments (Tables)	9 Months Ended
	Oct. 01, 2017
Cash and Cash Equivalents [Abstract]
Components of Cash, Cash Equivalents, and Investments	Cash, cash equivalents, and investments consisted of the following (in thousands): October 1, 2017 December 31, 2016 Cash $ 104,649 $ 77,307 Money market instruments 6,700 2,334 Cash and cash equivalents 111,349 79,641 Treasury bills 70,184 67,175 Corporate bonds 65,569 141,188 Euro liquidity fund 52,312 46,499 Asset-backed securities 47,840 69,614 Sovereign bonds 20,945 7,298 Municipal bonds 8,805 6,517 Agency bonds 7,606 2,903 Short-term investments 273,261 341,194 Corporate bonds 245,940 169,952 Treasury bills 63,602 92,280 Asset-backed securities 59,069 26,946 Sovereign bonds 8,026 23,585 Agency bonds 5,639 10,339 Municipal bonds 4,225 1,233 Long-term investments 386,501 324,335 $ 771,111 $ 745,170
Summary of Available-for-Sale Investments	The following table summarizes the Company’s available-for-sale investments as of October 1, 2017 (in thousands): Amortized Gross Gross Fair Value Short-term: Treasury bills $ 70,311 $ — $ (127 ) 70,184 Corporate bonds 65,484 91 (6 ) 65,569 Euro liquidity fund 51,929 383 — 52,312 Asset-backed securities 47,839 13 (12 ) 47,840 Sovereign bonds 20,974 5 (34 ) 20,945 Municipal bonds 8,805 — — 8,805 Agency bonds 7,600 6 — 7,606 Long-term: Corporate bonds 245,046 1,013 (119 ) 245,940 Treasury bills 63,704 — (102 ) 63,602 Asset-backed securities 59,038 76 (45 ) 59,069 Sovereign bonds 8,059 7 (40 ) 8,026 Agency bonds 5,630 9 — 5,639 Municipal bonds 4,219 9 (3 ) 4,225 $ 658,638 $ 1,612 $ (488 ) $ 659,762
Gross Unrealized Losses and Fair Values for Available-for-Sale Investments	The following table summarizes the Company’s gross unrealized losses and fair values for available-for-sale investments in an unrealized loss position as of October 1, 2017 (in thousands): Unrealized Loss Position For: Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Treasury bills $ 95,174 $ (150 ) $ 33,627 $ (79 ) $ 128,801 $ (229 ) Asset-backed securities 51,878 (55 ) 8,770 (2 ) 60,648 (57 ) Corporate bonds 20,106 (33 ) 15,154 (92 ) 35,260 (125 ) Sovereign bonds 2,495 (5 ) 19,854 (69 ) 22,349 (74 ) Municipal bonds 1,356 (3 ) — — 1,356 (3 ) $ 171,009 $ (246 ) $ 77,405 $ (242 ) $ 248,414 $ (488 )
Effective Maturity Dates of Available-for-Sale Investments	The following table presents the effective maturity dates of the Company’s available-for-sale investments as of October 1, 2017 (in thousands): <1 year 1-2 Years 2-3 Years 3-4 Years 4-5 Years 5-7 Years Total Corporate bonds $ 65,569 $ 109,918 $ 77,430 $ 17,223 $ 39,956 $ 1,413 $ 311,509 Treasury bills 70,184 63,602 — — — — 133,786 Asset-backed securities 47,840 35,502 16,075 — 2,328 5,164 106,909 Euro liquidity fund 52,312 — — — — — 52,312 Sovereign bonds 20,945 4,599 3,427 — — — 28,971 Agency bonds 7,606 2,719 — — 2,920 — 13,245 Municipal bonds 8,805 2,869 1,356 — — — 13,030 $ 273,261 $ 219,209 $ 98,288 $ 17,223 $ 45,204 $ 6,577 $ 659,762

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Oct. 01, 2017
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted of the following (in thousands): October 1, 2017 December 31, 2016 Raw materials $ 23,146 $ 18,224 Work-in-process 1,631 2,760 Finished goods 23,284 6,000 $ 48,061 $ 26,984

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Oct. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying value of goodwill	The changes in the carrying value of goodwill were as follows (in thousands): Amount Balance as of December 31, 2016 $ 95,280 Acquisition of ViDi Systems S.A. 18,333 Acquisition of GVi Ventures, Inc. 1,476 Adjustment to EnShape goodwill (1,881 ) Balance as of October 1, 2017 $ 113,208

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Oct. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortized Intangible Assets	Amortized intangible assets consisted of the following (in thousands): Gross Carrying Value Accumulated Amortization Net Carrying Value Distribution networks $ 38,060 $ 38,060 $ — Completed technologies 13,687 3,571 10,116 Customer relationships 9,205 5,203 4,002 Non-compete agreements 370 61 309 Balance as of October 1, 2017 $ 61,322 $ 46,895 $ 14,427 Gross Carrying Value Accumulated Amortization Net Carrying Value Distribution networks $ 38,060 $ 37,422 $ 638 Completed technologies 8,003 2,098 5,905 Customer relationships 6,605 4,836 1,769 Balance as of December 31, 2016 $ 52,668 $ 44,356 $ 8,312
Estimated Amortization Expense Succeeding Fiscal Years	As of October 1, 2017, estimated future amortization expense related to intangible assets is as follows (in thousands): Year Ended December 31, Amount Remainder of fiscal 2017 $ 799 2018 3,196 2019 2,821 2020 2,305 2021 2,097 2022 1,691 Thereafter 1,518 $ 14,427

Warranty Obligations (Tables)

Warranty Obligations (Tables)	9 Months Ended
	Oct. 01, 2017
Product Warranties Disclosures [Abstract]
Changes in Warranty Obligations	The changes in the warranty obligation were as follows (in thousands): Balance as of December 31, 2016 $ 4,335 Provisions for warranties issued during the period 2,322 Fulfillment of warranty obligations (2,323 ) Foreign exchange rate changes 545 Balance as of October 1, 2017 $ 4,879

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Oct. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding Forward Contracts Table	The Company had the following outstanding forward contracts (in thousands): October 1, 2017 December 31, 2016 Currency Notional USD Notional USD Derivatives Designated as Hedging Instruments: Japanese Yen — $ — 342,500 $ 2,960 Hungarian Forint — — 39,000 130 Singapore Dollar — — 150 97 Derivatives Not Designated as Hedging Instruments: Japanese Yen 500,000 $ 4,440 650,000 $ 5,554 British Pound 1,720 2,294 1,350 1,658 Hungarian Forint 530,000 2,014 425,000 1,448 Korean Won 1,325,000 1,154 1,750,000 1,450 Singapore Dollar — — 1,350 929 Taiwanese Dollar 34,640 1,139 26,000 802 Swiss Franc 1,025 1,059 — —
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	Information regarding the fair value of the outstanding forward contracts was as follows (in thousands): Asset Derivatives Liability Derivatives Balance Fair Value Balance Fair Value Sheet October 1, 2017 December 31, 2016 Sheet October 1, 2017 December 31, 2016 Derivatives Designated as Hedging Instruments: Cash flow hedge forward contracts Prepaid expenses and other current assets $ — $ 43 Accrued expenses $ — $ — Derivatives Not Designated as Hedging Instruments: Economic hedge forward contracts Prepaid expenses and other current assets $ 13 $ 1 Accrued expenses $ 13 $ 11
Offsetting Assets	The following table presents the gross activity for all derivative assets and liabilities which were presented on a net basis on the Consolidated Balance Sheets due to the right of offset with each counterparty (in thousands): Asset Derivatives Liability Derivatives October 1, 2017 December 31, 2016 October 1, 2017 December 31, 2016 Gross amounts of recognized assets $ 13 $ 117 Gross amounts of recognized liabilities $ 13 $ 11 Gross amounts offset — (73 ) Gross amounts offset — — Net amount of assets presented $ 13 $ 44 Net amount of liabilities presented $ 13 $ 11
Derivative Instruments, Gain (Loss)	Information regarding the effect of derivative instruments on the consolidated financial statements was as follows (in thousands): Location in Financial Statements Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Derivatives Designated as Hedging Instruments: Gains (losses) recorded in shareholders' equity (effective portion) Accumulated other comprehensive income (loss), net of tax $ — $ (332 ) $ — $ (332 ) Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion) Revenue $ 56 $ (250 ) $ 10 $ (453 ) Research, development, and engineering expenses — 1 3 5 Selling, general, and administrative expenses — 8 8 21 Total gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations $ 56 $ (241 ) $ 21 $ (427 ) Derivatives Not Designated as Hedging Instruments: Gains (losses) recognized in current operations Foreign currency gain (loss) $ 43 $ (24 ) $ 139 $ (1,089 )
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	The following table provides the changes in accumulated other comprehensive income (loss), net of tax, related to derivative instruments (in thousands): Balance as of December 31, 2016 $ 37 Net unrealized loss on cash flow hedges (16 ) Reclassification of net realized gain on cash flow hedges into current operations (21 ) Balance as of October 1, 2017 $ —

Stock-Based Compensation Expe33

Stock-Based Compensation Expense (Tables)	9 Months Ended
	Oct. 01, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity for the nine -month period ended October 1, 2017 : Shares (in thousands) Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2016 6,433 $ 32.16 Granted 1,980 77.87 Exercised (1,731 ) 25.85 Forfeited or expired (84 ) 45.57 Outstanding as of October 1, 2017 6,598 $ 47.36 7.77 $ 415,030 Exercisable as of October 1, 2017 1,707 $ 27.96 5.68 $ 140,559 Options vested or expected to vest as of October 1, 2017 (1) 5,795 $ 45.86 7.63 $ 373,276 (1) In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest are calculated by applying an estimated forfeiture rate to the unvested options.
Weighted-Average Assumptions Used in Estimating Fair Values of Stock Options Granted	The fair values of stock options granted in each period presented were estimated using the following weighted-average assumptions: Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Risk-free rate 2.4 % 1.7 % 2.4 % 1.7 % Expected dividend yield 0.39 % 0.84 % 0.39 % 0.84 % Expected volatility 41 % 41 % 41 % 41 % Expected term (in years) 5.1 5.5 5.3 5.5
Nonvested Restricted Stock Shares Activity	The following table summarizes the Company's restricted stock activity for the nine-month period ended October 1, 2017 : Shares (in thousands) Weighted-Average Grant Fair Value Aggregate Intrinsic Value (in thousands)(1) Nonvested as of December 31, 2016 20 $ 34.05 Granted — — Vested (10 ) 34.05 825 Forfeited or expired — — Nonvested as of October 1, 2017 10 $ 34.05 $ 1,103
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	The following table presents the stock-based compensation expense by caption for each period presented on the Consolidated Statements of Operations (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Cost of revenue $ 520 $ 273 $ 1,404 $ 795 Research, development, and engineering 2,765 1,366 8,090 4,942 Selling, general, and administrative 4,741 2,983 13,861 10,146 $ 8,026 $ 4,622 $ 23,355 $ 15,883

Taxes (Tables)

Taxes (Tables)	9 Months Ended
	Oct. 01, 2017
Income Tax Disclosure [Abstract]
Reconciliation of United States Federal Statutory Corporate Tax Rate to Company's Effective Tax Rate, or Income Tax Provision	A reconciliation of the United States federal statutory corporate tax rate to the Company’s income tax expense on continuing operations, or effective tax rate, was as follows: Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Income tax provision at federal statutory corporate tax rate 35 % 35 % 35 % 35 % State income taxes, net of federal benefit 1 % 1 % 1 % 1 % Foreign tax rate differential (18 )% (17 )% (18 )% (17 )% Tax credit (1 )% (1 )% (1 )% (1 )% Discrete tax benefit related to stock option exercises (7 )% (11 )% (13 )% (6 )% Other discrete tax events (2 )% (2 )% (1 )% (1 )% Other 1 % — % 1 % — % Income tax provision on continuing operations 9 % 5 % 4 % 11 %

Weighted-Average Shares (Tables

Weighted-Average Shares (Tables)	9 Months Ended
	Oct. 01, 2017
Earnings Per Share [Abstract]
Calculation of Weighted-Average Shares	Weighted-average shares were calculated as follows (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Basic weighted-average common shares outstanding 86,617 85,460 86,526 85,167 Effect of dilutive stock options 3,060 1,886 3,036 1,638 Weighted-average common and common-equivalent shares outstanding 89,677 87,346 89,562 86,805

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Oct. 01, 2017
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Discontinued Operations	The losses included in discontinued operations were as follows (in thousands): Three-months Ended Nine-months Ended October 1, 2017 October 2, 2016 October 1, 2017 October 2, 2016 Operating income from discontinued operations $ — $ — $ — $ — Gain (loss) on sale of discontinued operations — — — (404 ) Income (loss) from discontinued operations before income tax expense (benefit) — — — (404 ) Income tax expense (benefit) on discontinued operations — — — (149 ) Net income (loss) from discontinued operations $ — $ — $ — $ (255 )

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Oct. 01, 2017
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The purchase price was allocated as follows (in thousands): Accounts receivable $ 423 Inventories 120 Prepaid expenses and other current assets 1 Accounts payable (152 ) Accrued expenses (10 ) Completed technologies 910 Customer relationships 2,600 Goodwill 1,476 Purchase price $ 5,368 The purchase price was allocated as follows (in thousands): Cash $ 146 Accounts receivable 425 Prepaid expenses and other current assets 129 Property, plant, and equipment 40 Deferred income tax asset 620 Accounts payable (98 ) Accrued expenses (716 ) Deferred income tax liability (1,008 ) Non-compete agreement 370 Completed technologies 4,774 Goodwill 18,333 Purchase price $ 23,015

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Assets:
Money market instruments	$ 6,700	$ 2,334
Financial assets at fair value	659,762
Corporate Bonds
Assets:
Financial assets at fair value	311,509
Treasury Bills
Assets:
Financial assets at fair value	133,786
Asset-Backed Securities
Assets:
Financial assets at fair value	106,909
Euro Liquidity Fund
Assets:
Financial assets at fair value	52,312
Sovereign Bonds
Assets:
Financial assets at fair value	28,971
Agency Bonds
Assets:
Financial assets at fair value	13,245
Municipal Bonds
Assets:
Financial assets at fair value	13,030
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Money market instruments	6,700
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Money market instruments	0
Economic hedge forward contracts	0
Liabilities:
Economic hedge forward contracts	13
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate Bonds
Assets:
Financial assets at fair value	311,509
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Treasury Bills
Assets:
Financial assets at fair value	133,786
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Asset-Backed Securities
Assets:
Financial assets at fair value	106,909
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Euro Liquidity Fund
Assets:
Financial assets at fair value	52,312
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Sovereign Bonds
Assets:
Financial assets at fair value	28,971
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Agency Bonds
Assets:
Financial assets at fair value	13,245
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Municipal Bonds
Assets:
Financial assets at fair value	13,030
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Liabilities:
Contingent consideration liabilities	$ 3,673

Fair Value Measurements - Liabi

Fair Value Measurements - Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payment of contingent consideration	$ (1,926)	$ (337)
Foreign Currency Transaction Gain (Loss), Unrealized	39
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	4,173
Ending balance	3,673
EnShape | Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payment of contingent consideration	(1,401)
Manatee | Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payment of contingent consideration	(525)
Fair value adjustment to Manatee contingent consideration	(275)
Chiaro | Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value adjustment to Manatee contingent consideration	185
GVi
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value adjustment to Chiaro contingent consideration	1,299
GVi | Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value adjustment to Manatee contingent consideration	$ 178

Cash, Cash Equivalents, and I40

Cash, Cash Equivalents, and Investments (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Cash and Cash Equivalents [Abstract]
Gross realized gains on sale of investments	$ 306,000	$ 55,000	$ 449,000	$ 280,000
Gross realized losses on sale of investments	$ 43,000	$ 0	$ 79,000	$ 97,000

Cash, Cash Equivalents, and I41

Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Detail) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016	Oct. 02, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 104,649	$ 77,307
Money market instruments	6,700	2,334
Cash and cash equivalents	111,349	79,641	$ 61,145	$ 51,975
Short-term investments	273,261	341,194
Long-term investments	386,501	324,335
Total	771,111	745,170
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	70,184	67,175
Long-term investments	63,602	92,280
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	65,569	141,188
Long-term investments	245,940	169,952
Euro Liquidity Fund
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	52,312	46,499
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	47,840	69,614
Long-term investments	59,069	26,946
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	20,945	7,298
Long-term investments	8,026	23,585
Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	7,606	2,903
Long-term investments	5,639	10,339
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	8,805	6,517
Long-term investments	$ 4,225	$ 1,233

Cash, Cash Equivalents, and I42

Cash, Cash Equivalents, and Investments - Summary of Available-for-Sale Investments (Detail) $ in Thousands	Oct. 01, 2017USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 658,638
Gross unrealized gains	1,612
Gross unrealized losses	(488)
Fair value	659,762
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	(229)
Treasury Bills | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	70,311
Gross unrealized gains	0
Gross unrealized losses	(127)
Fair value	70,184
Treasury Bills | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	63,704
Gross unrealized gains	0
Gross unrealized losses	(102)
Fair value	63,602
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	(125)
Corporate Bonds | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	65,484
Gross unrealized gains	91
Gross unrealized losses	(6)
Fair value	65,569
Corporate Bonds | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	245,046
Gross unrealized gains	1,013
Gross unrealized losses	(119)
Fair value	245,940
Euro Liquidity Fund | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	51,929
Gross unrealized gains	383
Gross unrealized losses	0
Fair value	52,312
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	(57)
Asset-Backed Securities | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	47,839
Gross unrealized gains	13
Gross unrealized losses	(12)
Fair value	47,840
Asset-Backed Securities | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	59,038
Gross unrealized gains	76
Gross unrealized losses	(45)
Fair value	59,069
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	(74)
Sovereign Bonds | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	20,974
Gross unrealized gains	5
Gross unrealized losses	(34)
Fair value	20,945
Sovereign Bonds | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	8,059
Gross unrealized gains	7
Gross unrealized losses	(40)
Fair value	8,026
Agency Bonds | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	7,600
Gross unrealized gains	6
Gross unrealized losses	0
Fair value	7,606
Agency Bonds | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,630
Gross unrealized gains	9
Gross unrealized losses	0
Fair value	5,639
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	(3)
Municipal Bonds | Short-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	8,805
Gross unrealized gains	0
Gross unrealized losses	0
Fair value	8,805
Municipal Bonds | Long-Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	4,219
Gross unrealized gains	9
Gross unrealized losses	(3)
Fair value	$ 4,225

Cash, Cash Equivalents, and I43

Cash, Cash Equivalents, and Investments - Gross Unrealized Losses and Fair Values for Available-for-Sale Investments (Detail) $ in Thousands	Oct. 01, 2017USD ($)
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	$ 171,009
Unrealized losses, less than 12 months	(246)
Fair value, 12 months or greater	77,405
Unrealized losses, 12 months or greater	(242)
Total fair value	248,414
Total unrealized losses	(488)
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	95,174
Unrealized losses, less than 12 months	(150)
Fair value, 12 months or greater	33,627
Unrealized losses, 12 months or greater	(79)
Total fair value	128,801
Total unrealized losses	(229)
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	51,878
Unrealized losses, less than 12 months	(55)
Fair value, 12 months or greater	8,770
Unrealized losses, 12 months or greater	(2)
Total fair value	60,648
Total unrealized losses	(57)
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	2,495
Unrealized losses, less than 12 months	(5)
Fair value, 12 months or greater	19,854
Unrealized losses, 12 months or greater	(69)
Total fair value	22,349
Total unrealized losses	(74)
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	1,356
Unrealized losses, less than 12 months	(3)
Fair value, 12 months or greater	0
Unrealized losses, 12 months or greater	0
Total fair value	1,356
Total unrealized losses	(3)
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	20,106
Unrealized losses, less than 12 months	(33)
Fair value, 12 months or greater	15,154
Unrealized losses, 12 months or greater	(92)
Total fair value	35,260
Total unrealized losses	$ (125)

Cash, Cash Equivalents, and I44

Cash, Cash Equivalents, and Investments - Effective Maturity Dates of Available-for-Sale Investments (Detail) $ in Thousands	Oct. 01, 2017USD ($)
Schedule of Available-for-sale Securities [Line Items]
1 year or less	$ 273,261
1-2 years	219,209
2-3 years	98,288
3-4 years	17,223
4-5 years	45,204
5-7 years	6,577
Fair value	659,762
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
1 year or less	65,569
1-2 years	109,918
2-3 years	77,430
3-4 years	17,223
4-5 years	39,956
5-7 years	1,413
Fair value	311,509
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
1 year or less	70,184
1-2 years	63,602
2-3 years	0
3-4 years	0
4-5 years	0
5-7 years	0
Fair value	133,786
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
1 year or less	47,840
1-2 years	35,502
2-3 years	16,075
3-4 years	0
4-5 years	2,328
5-7 years	5,164
Fair value	106,909
Euro Liquidity Fund
Schedule of Available-for-sale Securities [Line Items]
1 year or less	52,312
1-2 years	0
2-3 years	0
3-4 years	0
4-5 years	0
5-7 years	0
Fair value	52,312
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
1 year or less	20,945
1-2 years	4,599
2-3 years	3,427
3-4 years	0
4-5 years	0
5-7 years	0
Fair value	28,971
Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
1 year or less	7,606
1-2 years	2,719
2-3 years	0
3-4 years	0
4-5 years	2,920
5-7 years	0
Fair value	13,245
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
1 year or less	8,805
1-2 years	2,869
2-3 years	1,356
3-4 years	0
4-5 years	0
5-7 years	0
Fair value	$ 13,030

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 23,146	$ 18,224
Work-in-process	1,631	2,760
Finished goods	23,284	6,000
Inventories	$ 48,061	$ 26,984

Goodwill - Changes in the Carry

Goodwill - Changes in the Carrying Value of Goodwill (Details) $ in Thousands	9 Months Ended
	Oct. 01, 2017USD ($)
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 95,280
Goodwill, Ending Balance	113,208
ViDi Systems S.A.
Goodwill [Line Items]
Acquisition of ViDi Systems S.A.	18,333
Acquisition of GVi Ventures, Inc.	18,333
GVi Ventures, Inc.
Goodwill [Line Items]
Acquisition of ViDi Systems S.A.	1,476
Acquisition of GVi Ventures, Inc.	1,476
EnShape
Goodwill [Line Items]
Adjustment to EnShape goodwill	$ (1,881)

Intangible Assets - Amortized I

Intangible Assets - Amortized Intangible Assets (Details) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 61,322	$ 52,668
Accumulated Amortization	46,895	44,356
Net Carrying Value	14,427	8,312
Distribution networks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	38,060	38,060
Accumulated Amortization	38,060	37,422
Net Carrying Value	0	638
Completed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	13,687	8,003
Accumulated Amortization	3,571	2,098
Net Carrying Value	10,116	5,905
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	9,205	6,605
Accumulated Amortization	5,203	4,836
Net Carrying Value	4,002	$ 1,769
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	370
Accumulated Amortization	61
Net Carrying Value	$ 309

Intangible Assets - Estimated A

Intangible Assets - Estimated Amortization Expense Succeeding Fiscal Years (Details) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of fiscal 2017	$ 799
2,018	3,196
2,019	2,821
2,020	2,305
2,021	2,097
2,022	1,691
Thereafter	1,518
Net Carrying Value	$ 14,427	$ 8,312

Warranty Obligations - Changes

Warranty Obligations - Changes in Warranty Obligations (Detail) $ in Thousands	9 Months Ended
	Oct. 01, 2017USD ($)
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 4,335
Provisions for warranties issued during the period	2,322
Fulfillment of warranty obligations	(2,323)
Foreign exchange rate changes	545
Ending balance	$ 4,879

Derivative Instruments (Detail)

Derivative Instruments (Detail)	9 Months Ended
	Oct. 01, 2017Category
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Number of Instruments Held	2
Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maximum length of time hedged in cash flow hedge	18 months
Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Remaining maturity of foreign currency derivatives (up to)	45 days

Derivative Instruments - Outsta

Derivative Instruments - Outstanding Forward Contracts Table (Detail) ₩ in Thousands, ¥ in Thousands, £ in Thousands, TWD in Thousands, SGD in Thousands, HUF in Thousands, $ in Thousands

Oct. 01, 2017HUF

Oct. 01, 2017GBP (£)

Oct. 01, 2017SGD

Oct. 01, 2017JPY (¥)

Oct. 01, 2017KRW (₩)

Oct. 01, 2017TWD

Oct. 01, 2017USD ($)

Dec. 31, 2016HUF

Dec. 31, 2016GBP (£)

Dec. 31, 2016SGD

Dec. 31, 2016JPY (¥)

Dec. 31, 2016KRW (₩)

Dec. 31, 2016TWD

Dec. 31, 2016USD ($)

Designated as Hedging Instrument | Japanese Yen

Derivative [Line Items]

Outstanding forward contracts

¥ 0

$ 0

¥ 342,500

$ 2,960

Designated as Hedging Instrument | Hungarian Forint

Derivative [Line Items]

Outstanding forward contracts

HUF 0

0

HUF 39,000

130

Designated as Hedging Instrument | Singapore Dollar

Derivative [Line Items]

Outstanding forward contracts

SGD 0

0

SGD 150

97

Not Designated as Hedging Instrument | Japanese Yen

Derivative [Line Items]

Outstanding forward contracts

¥ 500,000

4,440

¥ 650,000

5,554

Not Designated as Hedging Instrument | Hungarian Forint

Derivative [Line Items]

Outstanding forward contracts

HUF 530,000

2,014

HUF 425,000

1,448

Not Designated as Hedging Instrument | Singapore Dollar

Derivative [Line Items]

Outstanding forward contracts

SGD 0

0

SGD 1,350

929

Not Designated as Hedging Instrument | British Pound

Derivative [Line Items]

Outstanding forward contracts

£ 1,720

2,294

£ 1,350

1,658

Not Designated as Hedging Instrument | Korean Won

Derivative [Line Items]

Outstanding forward contracts

₩ 1,325,000

1,154

₩ 1,750,000

1,450

Not Designated as Hedging Instrument | Taiwanese Dollar

Derivative [Line Items]

Outstanding forward contracts

TWD 34,640

$ 1,139

TWD 26,000

$ 802

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative asset	$ 13	$ 44
Derivative liability	13	11
Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative asset	0	43
Designated as Hedging Instrument | Accrued Expenses
Derivatives, Fair Value [Line Items]
Derivative liability	0	0
Not Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative asset	13	1
Not Designated as Hedging Instrument | Accrued Expenses
Derivatives, Fair Value [Line Items]
Derivative liability	$ 13	$ 11

Derivative Instruments - Offset

Derivative Instruments - Offsetting Assets (Detail) - USD ($) $ in Thousands	Oct. 01, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross amounts of recognized assets	$ 13	$ 117
Gross amounts offset	0	(73)
Net amount of assets presented	13	44
Gross amounts of recognized liabilities	13	11
Gross amounts offset	0	0
Net amount of liabilities presented	$ 13	$ 11

Derivative Instruments - Deriva

Derivative Instruments - Derivative Instruments, Gain (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations	$ 56	$ (241)	$ 21	$ (427)
Designated as Hedging Instrument | Accumulated Other Comprehensive Income (Loss), Net of Tax
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in shareholders' equity (effective portion)	0	(332)	0	(332)
Designated as Hedging Instrument | Product Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	56	(250)	10	(453)
Designated as Hedging Instrument | Research, Development, and Engineering Expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	0	1	3	5
Designated as Hedging Instrument | Selling, General, and Administrative Expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	0	8	8	21
Not Designated as Hedging Instrument | Foreign Currency Gain (Loss)
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in current operations	$ 43	$ (24)	$ 139	$ (1,089)

Derivative Instruments - Sche55

Derivative Instruments - Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) (Detail)	9 Months Ended
	Oct. 01, 2017USD ($)
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ (56,428,000)
Ending balance	(37,101,000)
Net gains expected to be reclassified from OCI into Net Income, net of tax, 12 months	0
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	37,000
Net unrealized loss on cash flow hedges	(16,000)
Reclassification of net realized gain on cash flow hedges into current operations	(21,000)
Ending balance	$ 0

Stock-Based Compensation Expe56

Stock-Based Compensation Expense (Detail)	3 Months Ended				9 Months Ended
	Oct. 01, 2017USD ($)group$ / sharesshares	Apr. 02, 2017USD ($)	Oct. 02, 2016USD ($)$ / shares	Apr. 03, 2016USD ($)	Oct. 01, 2017USD ($)group$ / sharesshares	Oct. 02, 2016USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.39%		0.84%		0.39%	0.84%
Groups within the employee population | group	2				2
Percentage of stock options granted to senior management expected to vest	75.00%				75.00%
Percentage of stock options granted to all other employees expected to vest	72.00%				72.00%
Estimated annual forfeiture rate for unvested options for senior management	10.00%				10.00%
Estimated annual forfeiture rate for unvested options for all other employees	12.00%				12.00%
Increase (decrease) to compensation expense		$ 673,000		$ 334,000
Weighted-average grant-date fair values, in dollars per share | $ / shares	$ 29.59		$ 12.34		$ 29.94	$ 12.25
Total intrinsic value	$ 28,462,000		$ 23,139,000		$ 100,913,000	$ 32,514,000
Total fair values of stock options vest	844,000		679,000		19,557,000	16,724,000
Unrecognized compensation expense	41,354,000				$ 41,354,000
Weighted average period to be recognized					1 year 8 months 1 day
Stock-based compensation expense	8,026,000		4,622,000		$ 23,355,000	15,883,000
Tax benefit from compensation expense	2,639,000		$ 1,520,000		7,661,000	$ 5,210,000
Recognized period costs capitalized	$ 0				$ 0
Vesting period, performance-based restricted stock, years					1 year
Vesting period, time-based restricted stock, years					3 years
General Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock option plans					4 years
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans | shares	6,183,376				6,183,376
Expiration period from grant day					10 years

Stock-Based Compensation Expe57

Stock-Based Compensation Expense - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Oct. 01, 2017	Oct. 01, 2017
Shares (in thousands)
Outstanding, shares	6,433
Granted, shares	1,980
Exercised, shares	(1,731)
Forfeited or expired, shares	(84)
Outstanding, shares	6,598
Exercisable as of reporting date, shares		1,707
Options vested or expected to vest as of reporting date, shares		5,795
Weighted- Average Exercise Price
Outstanding, shares	$ 32.16
Granted, in dollars per share	77.87
Exercised, in dollars per share	25.85
Forfeited or expired, in dollars per share	45.57
Outstanding, shares	47.36
Outstanding	$ 32.16	$ 47.36
Exercisable as of reporting date, Weighted-Average Exercise Price, in dollars per share		27.96
Weighted- Average Remaining Contractual Term (in years)		$ 45.86
Weighted- Average Remaining Contractual Term (in years)
Outstanding, in years	7 years 9 months 7 days
Exercisable, in years	5 years 8 months 5 days
Options vested or expected to vest, in years	7 years 7 months 17 days
Aggregate Intrinsic Value (in thousands)
Outstanding, in dollars		$ 415,030
Exercisable, in dollars		140,559
Options vested or expected to vest, in dollars		$ 373,276

Stock-Based Compensation Expe58

Stock-Based Compensation Expense - Weighted-Average Assumptions Used in Estimating Fair Values of Stock Options Granted (Detail)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk-free rate	2.40%	1.70%	2.40%	1.70%
Expected dividend yield	0.39%	0.84%	0.39%	0.84%
Expected volatility	41.00%	41.00%	41.00%	41.00%
Expected term (in years)	5 years 1 month 6 days	5 years 6 months	5 years 3 months 18 days	5 years 6 months

Stock-Based Compensation Expe59

Stock-Based Compensation Expense - Nonvested Restricted Stock Shares Activity (Details) - Restricted Stock $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Oct. 01, 2017USD ($)$ / sharesshares
Shares (in thousands)
Nonvested, shares | shares	20
Granted, shares | shares	0
Vested, shares | shares	(10)
Forfeited or expired, shares | shares	0
Nonvested, shares | shares	10
Weighted-Average Grant Fair Value
Nonvested, in dollars per share | $ / shares	$ 34.05
Granted, in dollars per share | $ / shares	0
Vested, in dollars per share | $ / shares	34.05
Forfeited or expired, in dollars per share | $ / shares	0
Nonvested, in dollars per share | $ / shares	$ 34.05
Aggregate Intrinsic Value (in thousands)(1)
Vested | $	$ 825
Nonvested as of October 1, 2017 | $	$ 1,103

Stock-Based Compensation Expe60

Stock-Based Compensation Expense - Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,026,000	$ 4,622,000	$ 23,355,000	$ 15,883,000
Cost of Revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	520,000	273,000	1,404,000	795,000
Research, Development, and Engineering Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,765,000	1,366,000	8,090,000	4,942,000
Selling, General, and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,741,000	$ 2,983,000	$ 13,861,000	$ 10,146,000

Stock Repurchase Program (Detai

Stock Repurchase Program (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Oct. 01, 2017	Oct. 01, 2017	Apr. 28, 2017	Aug. 03, 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchased during period, Value		$ 99,347,000
Repurchase Program 2015
Equity, Class of Treasury Stock [Line Items]
Authorized common stock to be repurchased				$ 100,000,000
Stock Repurchased During Period, Shares	1,335,000	796,000
Stock repurchased during period, Value	$ 100,000,000	$ 68,915,000
Stock Repurchase Program April 2017
Equity, Class of Treasury Stock [Line Items]
Authorized common stock to be repurchased			$ 100,000,000
Stock Repurchased During Period, Shares		288,000
Stock repurchased during period, Value		$ 30,432,000

Taxes - Reconciliation of Unite

Taxes - Reconciliation of United States Federal Statutory Corporate Tax Rate to Company's Effective Tax Rate, or Income Tax Provision (Detail)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Income Tax Disclosure [Abstract]
Income tax provision at federal statutory corporate tax rate	35.00%	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	1.00%	1.00%	1.00%	1.00%
Foreign tax rate differential	(18.00%)	(17.00%)	(18.00%)	(17.00%)
Tax credit	(1.00%)	(1.00%)	(1.00%)	(1.00%)
Discrete tax benefit related to stock option exercises	(7.00%)	(11.00%)	(13.00%)	(6.00%)
Other discrete tax events	(2.00%)	(2.00%)	(1.00%)	(1.00%)
Other	1.00%	0.00%	1.00%	0.00%
Income tax provision on continuing operations	9.00%	5.00%	4.00%	11.00%

Taxes (Detail)

Taxes (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Income tax provision at federal statutory corporate tax rate	35.00%	35.00%	35.00%	35.00%
Decrease in effective tax rate	18.00%	17.00%	18.00%	17.00%
Decrease in effective tax rate for difference between deduction for tax purposes and compensation cost recognized from stock option exercises	7.00%	11.00%	13.00%	6.00%
Increase in reserves for income taxes, net of deferred tax benefit	$ 201,000		$ 201,000
Interest and penalties included in reserve			22,000
Liability for uncertain tax positions	6,591,000		6,591,000
Reserve for income taxes classified as a noncurrent iability	5,563,000		5,563,000		$ 5,361,000
Reserve for income taxes classified an noncurrent deferred tax assets	1,028,000		1,028,000
Interest and penalties, gross	$ 701,000		701,000
Minimum decrease in income tax expense due to release in reserves			1,000,000
Maximum decrease in income tax expense due to release in reserves			$ 1,200,000
Tax years open to examination by Internal Revenue Service			2014 through 2016
Tax years open to examination by various taxing authorities for other entities			2013 through 2016
Foreign Tax Authority | Revenue Commissioners, Ireland
Income Tax Contingency [Line Items]
Income tax provision at federal statutory corporate tax rate			12.50%
Foreign Tax Authority | State Administration of Taxation, China
Income Tax Contingency [Line Items]
Income tax provision at federal statutory corporate tax rate			25.00%
Domestic Tax Authority
Income Tax Contingency [Line Items]
Income tax provision at federal statutory corporate tax rate			35.00%

Weighted-Average Shares (Detail

Weighted-Average Shares (Detail) - shares	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Earnings Per Share [Abstract]
Stock options to purchase anti-dilutive common stock	233,081	491,375	1,554,129	3,641,279

Weighted-Average Shares - Calcu

Weighted-Average Shares - Calculation of Weighted-Average Shares (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Earnings Per Share [Abstract]
Basic weighted-average common shares outstanding	86,617	85,460	86,526	85,167
Effect of dilutive stock options	3,060	1,886	3,036	1,638
Weighted-average common and common-equivalent shares outstanding	89,677	87,346	89,562	86,805

Discontinued Operations - Sched

Discontinued Operations - Schedule of Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Revenue and Expenses
Income (loss) from discontinued operations before income tax expense (benefit)	$ 0	$ 0	$ 0	$ (255)
SISD | Discontinued Operations, Disposed of by Sale
Revenue and Expenses
Operating income from discontinued operations	0	0	0	0
Gain (loss) on sale of discontinued operations	0	0	0	(404)
Income (loss) from discontinued operations before income tax expense (benefit)	0	0	0	(404)
Income tax expense (benefit) on discontinued operations	0	0	0	(149)
Net income (loss) from discontinued operations	$ 0	$ 0	$ 0	$ (255)

Discontinued Operations (Detail

Discontinued Operations (Details) - SISD - Discontinued Operations, Disposed of by Sale - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit) on discontinued operations	$ 0	$ 0	$ 0	$ (149,000)
Net income (loss) from discontinued operations	0	$ 0	$ 0	$ (255,000)
AMETEK Matter | Guarantee Obligations | Settled Litigation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Damages awarded, refund of product purchase price	326,000
Damages awarded, reimbursement of legal fees	45,000
Net settlement	281,000
Legal fees	123,000
Income tax expense (benefit) on discontinued operations	(149,000)
Net income (loss) from discontinued operations	$ (255,000)

Acquisitions (Details)

Acquisitions (Details) - USD ($)	Apr. 12, 2017	Apr. 04, 2017	Oct. 01, 2017
ViDi Systems S.A.
Business Acquisition [Line Items]
Total purchase price		$ 23,015,000
Cash payment		20,019,000
Holdback to secure potential claims under agreement		$ 2,996,000
Holdback limitation period		18 months
tax deductible goodwill		$ 5,112,000
ViDi Systems S.A. | Completed technologies
Business Acquisition [Line Items]
Amortization period		6 years
ViDi Systems S.A. | Non-compete agreement
Business Acquisition [Line Items]
Amortization period		3 years
GVi Ventures, Inc.
Business Acquisition [Line Items]
Total purchase price	$ 5,368,000
Cash payment	4,069,000
Contingent consideration liabilities	1,299,000		$ 1,477,000
Contingent consideration, low range	0
Contingent consideration, high range	$ 3,500,000
Contingent consideration, period of recognition (in years)	5 years
Contingent consideration, current			311,000
Contingent consideration, noncurrent			$ 1,166,000
GVi Ventures, Inc. | Completed technologies
Business Acquisition [Line Items]
Amortization period	5 years
GVi Ventures, Inc. | Customer relationships
Business Acquisition [Line Items]
Amortization period	8 years

Acquisitions - Purchase Price A

Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Oct. 01, 2017	Apr. 12, 2017	Apr. 04, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 113,208			$ 95,280
ViDi Systems S.A.
Business Acquisition [Line Items]
Cash			$ 146
Accounts receivable			425
Prepaid expenses and other current assets			129
Property, plant, and equipment			40
Deferred income tax asset			620
Accounts payable			(98)
Accrued expenses			(716)
Deferred income tax liability			(1,008)
Goodwill			18,333
Purchase price			23,015
ViDi Systems S.A. | Non-compete agreement
Business Acquisition [Line Items]
Intangible assets			370
ViDi Systems S.A. | Completed technologies
Business Acquisition [Line Items]
Intangible assets			$ 4,774
GVi Ventures, Inc.
Business Acquisition [Line Items]
Accounts receivable		$ 423
Inventories		120
Prepaid expenses and other current assets		1
Accounts payable		(152)
Accrued expenses		(10)
Goodwill		1,476
Purchase price		5,368
GVi Ventures, Inc. | Completed technologies
Business Acquisition [Line Items]
Intangible assets		910
GVi Ventures, Inc. | Customer relationships
Business Acquisition [Line Items]
Intangible assets		$ 2,600

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event	Oct. 30, 2017USD ($)
Subsequent Event [Line Items]
Dividends (in dollars per share)	$ 0.09
Dividends payable, date payable	Dec. 1, 2017
Dividends payable, date of record	Nov. 17, 2017
Stock split ratio	2