Teradyne (TER) 10-Q 13 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Oct. 04, 2015	Nov. 06, 2015
Document Information
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 4, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	TER
Entity Registrant Name	TERADYNE, INC
Entity Central Index Key	97,210
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		205,517,339

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Oct. 04, 2015		Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 294,217		$ 294,256
Marketable securities	525,381		533,787
Accounts receivable, less allowance for doubtful accounts of $2,418 and $2,491 at October 4, 2015 and December 31, 2014, respectively	245,233		151,034
Inventories, net:
Parts	85,713		70,821
Assemblies in process	15,885		10,347
Finished goods	26,834		23,961
Inventory, Net, Total	128,432		105,129
Deferred tax assets	58,480		57,239
Prepayments	80,779		95,819
Other current assets	4,135		6,582
Total current assets	1,336,657		1,243,846
Property, plant and equipment, net	275,089		329,038
Marketable securities	257,560		470,789
Deferred tax assets	6,909		7,494
Other assets	13,096		10,419
Retirement plans assets	13,933		12,896
Intangible assets, net	260,294		190,600
Goodwill	498,346		273,438
Total assets	2,661,884	[1]	2,538,520
Current liabilities:
Accounts payable	81,642		47,763
Accrued employees' compensation and withholdings	98,252		100,994
Deferred revenue and customer advances	74,318		71,603
Other accrued liabilities	83,823		50,247
Contingent consideration	14,447		895
Accrued income taxes	43,259		20,049
Total current liabilities	395,741		291,551
Long-term deferred revenue and customer advances	29,490		19,929
Retirement plans liabilities	107,102		108,460
Deferred tax liabilities	35,494		23,315
Long-term other accrued liabilities	28,304		13,830
Long-term contingent consideration	20,148		2,455
Total liabilities	$ 616,279		$ 459,540
Commitments and contingencies (See Note P)
SHAREHOLDERS' EQUITY
Common stock, $0.125 par value, 1,000,000 shares authorized; 207,240 shares and 216,613 shares issued and outstanding at October 4, 2015 and December 31, 2014, respectively	$ 25,904		$ 27,077
Additional paid-in capital	1,471,641		1,437,135
Accumulated other comprehensive income	67		4,689
Retained earnings	547,993		610,079
Total shareholders' equity	2,045,605		2,078,980
Total liabilities and shareholders' equity	$ 2,661,884		$ 2,538,520
[1]	Total business assets are directly attributable to each business. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Accounts receivable, less allowance for doubtful accounts	$ 2,418	$ 2,491
Common stock, par value	$ 0.125	$ 0.125
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	207,240,000	216,613,000
Common stock, shares outstanding	207,240,000	216,613,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Revenues:
Products		$ 386,488	$ 402,987	$ 1,096,056	$ 1,110,861
Services		79,506	75,023	225,077	213,726
Total revenues		465,994	478,010	1,321,133	1,324,587
Cost of revenues:
Cost of products		170,963	182,591	471,450	509,450
Cost of services		36,405	34,298	100,067	96,556
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		207,368	216,889	571,517	606,006
Gross profit		258,626	261,121	749,616	718,581
Operating expenses:
Engineering and development		74,027	71,953	221,309	212,452
Selling and administrative		77,481	73,064	226,595	228,556
Acquired intangible assets amortization		20,053	18,271	49,119	54,813
Restructuring and other		261	(405)	(124)	167
Total operating expenses		171,822	162,883	496,899	495,988
Income from operations		86,804	98,238	252,717	222,593
Non-operating (income) expense:
Interest income		(1,708)	(1,922)	(5,198)	(4,224)
Interest expense		508	144	1,114	6,720
Other (income) expense, net		596	(654)	(5,180)	(92)
Income before income taxes	[1],[2]	87,408	100,670	261,981	220,189
Income tax provision		15,955	17,721	54,863	35,106
Net income		$ 71,453	$ 82,949	$ 207,118	$ 185,083
Net income per common share:
Basic		$ 0.34	$ 0.40	$ 0.97	$ 0.93
Diluted		$ 0.34	$ 0.38	$ 0.96	$ 0.83
Weighted average common shares-basic		210,032	207,381	213,688	198,367
Weighted average common shares-diluted		211,736	218,333	215,348	223,795
Cash dividend declared per common share		$ 0.06	$ 0.06	$ 0.18	$ 0.12
[1]	Included in the income (loss) before income taxes for each of the segments are charges related to inventory and other.
[2]	Interest income, interest expense, and other (income) expense, net are included in Corporate and Eliminations.

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Net income		$ 71,453	$ 82,949	$ 207,118	$ 185,083
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment, net of tax of $0		3,267		(3,000)
Available-for-sale marketable securities:
Unrealized gains (losses) on marketable securities arising during period, net of tax of $48, $(139), $(896), $1,103		283	(138)	(593)	2,166
Less: Reclassification adjustment for gains included in net income, net of tax of $(126), $(348), $(335), $(591)		(247)	(638)	(808)	(1,086)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total		36	(776)	(1,401)	1,080
Defined benefit pension and post-retirement plans:
Amortization of net prior service benefit included in net periodic pension expense and post-retirement benefit income, net of tax of $(42), $(42), $(127), $(127)	[1]	(74)	(74)	(221)	(221)
Other comprehensive income (loss)		3,229	(850)	(4,622)	859
Comprehensive income		$ 74,682	$ 82,099	$ 202,496	$ 185,942
[1]	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note O: "Retirement Plans."

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Foreign currency translation adjustments, tax	$ 0		$ 0
Unrealized gains (losses) on marketable securities arising during period, tax	48	$ (139)	(896)	$ 1,103
Reclassification adjustment for gains included in net income, tax	(126)	(348)	(335)	(591)
Amortization of prior service (benefit) costs, tax	$ (42)	$ (42)	$ (127)	$ (127)

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014
Cash flows from operating activities:
Net income	$ 207,118	$ 185,083
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	52,531	52,832
Amortization	52,159	62,122
Stock-based compensation	23,080	31,873
Provision for excess and obsolete inventory	18,939	21,505
Non-cash charge for the sale of inventories revalued at the date of acquisition	1,567
Tax benefit related to employee stock compensation awards	(3,213)	(1,726)
Contingent consideration adjustment	(2,600)	(630)
Gain from the sale of an equity investment	(5,406)
Deferred taxes	(13,973)	(8,747)
Other	2,523	2,110
Changes in operating assets and liabilities, net of business acquired:
Accounts receivable	(91,117)	(163,670)
Inventories	33,376	38,267
Prepayments and other assets	15,529	47,784
Accounts payable and other accrued expenses	52,663	29,109
Deferred revenue and customer advances	6,751	14,266
Retirement plans contributions	(2,998)	(3,281)
Accrued income taxes	25,677	10,208
Net cash provided by operating activities	372,606	317,105
Cash flows from investing activities:
Purchases of property, plant and equipment	(66,727)	(146,352)
Acquisition of business, net of cash acquired	(282,741)
Purchases of available-for-sale marketable securities	(957,606)	(844,056)
Proceeds from sales of available-for-sale marketable securities	843,734	236,060
Proceeds from maturities of available-for-sale marketable securities	330,363	495,565
Proceeds from the sale of an equity investment	5,406
Proceeds from life insurance	1,098	4,391
Net cash used for investing activities	(126,473)	(254,392)
Cash flows from financing activities:
Issuance of common stock under employee stock purchase and stock option plans	18,145	21,030
Tax benefit related to employee stock compensation awards	3,213	1,726
Repurchase of common stock	(226,843)
Dividend payments	(38,434)	(24,428)
Payment of revolving credit facility costs	(2,253)
Payments of long-term debt		(190,975)
Net cash used for financing activities	(246,172)	(192,647)
Decrease in cash and cash equivalents	(39)	(129,934)
Cash and cash equivalents at beginning of period	294,256	341,638
Cash and cash equivalents at end of period	$ 294,217	$ 211,704

The Company

The Company	9 Months Ended
	Oct. 04, 2015
The Company	A. The Company Teradyne, Inc. (“Teradyne”) is a leading global supplier of automation equipment for test and industrial applications. Teradyne’s automatic test equipment and industrial automation products and services include: • semiconductor test (“Semiconductor Test”) systems; • wireless test (“Wireless Test”) systems; • defense/aerospace (“Defense/Aerospace”) test instrumentation and systems, storage test (“Storage Test”) systems, and circuit-board test and inspection (“Production Board Test”) systems (collectively these products represent “System Test”); and • industrial automation (“Industrial Automation”) products include collaborative robots used by global manufacturing and light industrial customers to improve quality and increase manufacturing efficiency. On June 11, 2015, Teradyne acquired Universal Robots A/S (“Universal Robots”) for approximately $284 million of cash plus up to an additional $65 million of cash if certain performance targets are met extending through 2018. Universal Robots is the leading supplier of collaborative robots which are low-cost, easy-to-deploy and simple-to-program robots that work side by side with production workers to improve quality and increase manufacturing efficiency.

Accounting Policies

Accounting Policies	9 Months Ended
	Oct. 04, 2015
Accounting Policies	B. Accounting Policies Basis of Presentation The consolidated interim financial statements include the accounts of Teradyne and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated. These interim financial statements are unaudited and reflect all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of such interim financial statements. Certain prior year amounts were reclassified to conform to the current year presentation. The December 31, 2014 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 27, 2015, for the year ended December 31, 2014. Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the amounts reported in the financial statements. Actual results may differ significantly from these estimates. Revenue Recognition Teradyne recognizes revenue when there is persuasive evidence of an arrangement, title and risk of loss have passed, delivery has occurred or the services have been rendered, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Title and risk of loss generally pass to Teradyne’s customers upon shipment or at delivery destination point. In circumstances where either title or risk of loss pass upon destination, acceptance or cash payment, Teradyne defers revenue recognition until such events occur except when title transfer is tied to cash payment outside the United States. Outside the United States, Teradyne recognizes revenue upon shipment or at delivery destination point, even if Teradyne retains a form of title to products delivered to customers, provided the sole purpose is to enable Teradyne to recover the products in the event of customer payment default and the arrangement does not prohibit the customer’s use or resale of the product in the ordinary course of business. Teradyne’s equipment has non-software and software components that function together to deliver the equipment’s essential functionality. Revenue is recognized upon shipment or at delivery destination point, provided that customer acceptance criteria can be demonstrated prior to shipment. Certain contracts require Teradyne to perform tests of the product to ensure that performance meets the published product specifications or customer requested specifications, which are generally conducted prior to shipment. Where the criteria cannot be demonstrated prior to shipment, revenue is deferred until customer acceptance has been received. Teradyne also defers the portion of the sales price that is not due until acceptance, which represents deferred profit. For multiple element arrangements, Teradyne allocates revenue to all deliverables based on their relative selling prices. In such circumstances, a hierarchy is used to determine the selling price for allocating revenue to deliverables as follows: (i) vendor-specific objective evidence of selling price (“VSOE”), (ii) third-party evidence of selling price (“TPE”), and (iii) best estimate of the selling price (“BESP”). For a delivered item to be considered a separate unit the delivered item must have value to the customer on a standalone basis and the delivery or performance of the undelivered item must be considered probable and substantially in Teradyne’s control. Teradyne’s post-shipment obligations include installation, training services, one-year standard warranties, and extended warranties. Installation does not alter the product capabilities, does not require specialized skills or tools and can be performed by the customers or other vendors. Installation is typically provided within five days of product shipment and is completed within one to two days thereafter. Training services are optional and do not affect the customers’ ability to use the product. Teradyne defers revenue for the selling price of installation and training. Extended warranties constitute warranty obligations beyond one year and Teradyne defers revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 605-20, “Separately Priced Extended Warranty and Product Maintenance Contracts” “Revenue Recognition Multiple-Element Arrangements.” Teradyne’s products are generally subject to warranty and related costs of the warranty are provided for in cost of revenue when product revenue is recognized. Teradyne classifies shipping and handling costs in cost of revenue. Teradyne generally does not provide its customers with contractual rights of return for any of its products. Translation of Non-U.S. Currencies The functional currency for all non-U.S. subsidiaries is the U.S. dollar, except for the Industrial Automation segment for which the local currency is its functional currency. All foreign currency denominated monetary assets and liabilities are remeasured on a monthly basis into the functional currency using exchange rates in effect at the end of the period. All foreign currency denominated non-monetary assets and liabilities are remeasured into the functional currency using historical exchange rates. Net foreign exchange gains and losses resulting from remeasurement are included in other (income) expense, net. For Industrial Automation, assets and liabilities are translated into U.S. dollars using exchange rates in effect at the end of the period. Revenue and expense amounts are translated using an average of exchange rates in effect during the period. Translation adjustments are recorded within accumulated other comprehensive income (loss).

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Oct. 04, 2015
Recently Issued Accounting Pronouncements	C. Recently Issued Accounting Pronouncements In September 2015, the FASB issued Accounting Standard Update (“ASU”) 2015-16, “Business Combinations (Topic 805)—Simplifying the Accounting for Measurement-Period Adjustments ” On April 7, 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” “Interest—Imputation of Interest (Subtopic 835-30)” In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),”

Acquisitions

Acquisitions	9 Months Ended
	Oct. 04, 2015
Acquisitions	D. Acquisitions Universal Robots On June 11, 2015, Teradyne acquired all of the outstanding equity of Universal Robots located in Odense, Denmark. Universal Robots is the leading supplier of collaborative robots which are low-cost, easy-to-deploy and simple-to-program robots that work side by side with production workers to improve quality and increase manufacturing efficiency. Universal Robots is a separate operating and reportable segment, Industrial Automation. The total purchase price of $317.7 million consisted of $283.9 million of cash paid and $33.8 million of contingent consideration, measured at fair value. The contingent consideration is payable upon the achievement of certain thresholds and targets for earnings before income taxes, depreciation and amortization (“EBITDA”) for calendar year 2015, revenue for the period from July 1, 2015 to December 31, 2017 and revenue for the period from July 1, 2015 to December 31, 2018. The maximum amount of contingent consideration that could be paid is $65 million. The valuation of the contingent consideration utilized the following assumptions: (1) probability of meeting each target; (2) expected timing of meeting each target; and (3) discount rate reflecting the risk associated with the expected payments. The probabilities and timing for each target were estimated based on a review of the historical and projected results. Discount rates of 6 percent, 8 percent and 10 percent, respectively, were based on corporate bond yields adjusted for the level of difficulty to achieve and the term of the earn out payment. A significant portion of the risk in achieving the contingent consideration was captured in the probabilities assigned to meeting each target. The Universal Robots acquisition was accounted for as a business combination and, accordingly, the results have been included in Teradyne’s consolidated results of operations from the date of acquisition. The allocation of the total purchase price to Universal Robots’ net tangible liabilities and identifiable intangible assets was based on their estimated fair values as of the acquisition date. The excess of the purchase price over the identifiable intangible assets and net tangible liabilities in the amount of $227.0 million was allocated to goodwill, which is not deductible for tax purposes. The purchase price allocation is preliminary pending the final determination of the fair value of contingent consideration, acquired assets and assumed liabilities. Teradyne expects to finalize the purchase price calculation in the fourth quarter of 2015. The following table represents the preliminary allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 227,021 Intangible assets 119,950 Tangible assets acquired and liabilities assumed: Current assets 10,853 Non-current assets 3,415 Accounts payable and current liabilities (11,973 ) Long-term deferred tax liabilities (25,736 ) Long-term other liabilities (5,844 ) Total purchase price $317,686 Teradyne estimated the fair value of intangible assets using the income and cost approaches. Acquired intangible assets are amortized on a straight-line basis over their estimated useful lives. Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 88,890 4.9 Trademarks and tradenames 21,680 10.0 Customer relationships 9,380 2.0 Total intangible assets $ 119,950 5.6 For the three months ended October 4, 2015, Universal Robots contributed $16.1 million of revenues and had a $(4.8) million loss from operations before income taxes. For the period from June 12, 2015 to October 4, 2015, Universal Robots contributed $19.8 million of revenues and had a $(6.5) million loss from operations before income taxes. The following unaudited pro forma information gives effect to the acquisition of Universal Robots as if the acquisition occurred on January 1, 2014. The unaudited pro forma results are not necessarily indicative of what actually would have occurred had the acquisition been in effect for the periods presented: For the Three Months For the Nine Months Ended September 28, 2014 October 4, September 28, Revenue $ 485,842 $ 1,339,181 $ 1,347,616 Net income 76,112 197,745 162,474 Net income per common share: Basic $ 0.37 $ 0.93 $ 0.82 Diluted $ 0.35 $ 0.92 $ 0.73 Pro forma results for the nine months ended October 4, 2015 were adjusted to exclude $1.6 million of non-recurring expense related to the fair value adjustment to acquisition-date inventory and $1.0 million of acquisition related costs incurred in 2015. Pro forma results for the nine month ended September 28, 2014, were adjusted to include $1.6 million of non-recurring expense related to the fair value adjustment to acquisition-date inventory and $1.0 million of acquisition related costs. Avionics Interface Technologies, LLC. On October 31, 2014, Teradyne acquired substantially all of the assets and liabilities of Avionics Interface Technologies, LLC (“AIT”) located in Omaha, Nebraska. AIT is a supplier of equipment for testing state-of-the-art data communication buses. The acquisition of AIT complements Teradyne’s Defense/Aerospace line of bus test instrumentation for commercial and defense avionics systems. AIT is included in Teradyne’s System Test segment. The total purchase price of $21.2 million consisted of $19.4 million of cash paid and $1.8 million of contingent consideration, measured at fair value. The contingent consideration is payable upon achievement of certain revenue and gross margin targets in 2015 and 2016. The maximum amount of contingent consideration that could be paid is $2.1 million. The valuation of the contingent consideration utilized the following assumptions: (1) probability of meeting each target; (2) expected timing of meeting each target; and (3) discount rate reflecting the risk associated with the expected payments. The probabilities and timing for each target were estimated based on a review of the historical and projected results. A discount rate of 4.7 percent was selected based on the estimated cost of debt for the business. A significant portion of the risk in achieving the contingent consideration was captured in the probabilities assigned to meeting each target. In the three and nine months ended October 4, 2015, the fair value of contingent consideration for the earn-out in connection with the acquisition of AIT was reduced by $1.0 million due to a decrease in the revenue probabilities in the periods of 2015 and 2016. The AIT acquisition was accounted for as a business combination and, accordingly, the results have been included in Teradyne’s consolidated results of operations from the date of acquisition. The allocation of the total purchase price to AIT’s net tangible and identifiable intangible assets was based on their estimated fair values as of the acquisition date. The excess of the purchase price over the identifiable intangible and net tangible assets in the amount of $10.5 million was allocated to goodwill, which is deductible for tax purposes. The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 10,516 Intangible assets 9,080 Tangible assets acquired and liabilities assumed: Current assets 2,452 Non-current assets 359 Accounts payable and current liabilities (1,164 ) Total purchase price $ 21,243 Teradyne estimated the fair value of intangible assets using the income approach. Acquired intangible assets are amortized on a straight-line basis over their estimated useful lives. Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Customer relationships $ 5,630 5.0 Developed technology 2,580 4.8 Trademarks and tradenames 380 5.0 Non-compete agreement 320 4.0 Customer order backlog 170 0.3 Total intangible assets $ 9,080 4.8

Financial Instruments and Deriv

Financial Instruments and Derivatives	9 Months Ended
	Oct. 04, 2015
Financial Instruments and Derivatives	E. Financial Instruments and Derivatives Cash Equivalents Teradyne considers all highly liquid investments with maturities of three months or less at the date of acquisition to be cash equivalents. Marketable Securities Teradyne accounts for its investments in debt and equity securities in accordance with the provisions of Accounting Standards Codification (“ASC”) 320-10, “ Investments—Debt and Equity Securities. On a quarterly basis, Teradyne reviews its investments to identify and evaluate those that have an indication of a potential other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include: • The length of time and the extent to which the market value has been less than cost; • The financial condition and near-term prospects of the issuer; and • The intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value. Teradyne uses the market and income approach techniques to value its financial instruments and there were no changes in valuation techniques during the three and nine months ended October 4, 2015. As defined in ASC 820-10 “ Fair Value Measurements and Disclosures, Level 1: Quoted prices in active markets for identical assets as of the reporting date. Level 2: Inputs other than Level 1, that are observable either directly or indirectly as of the reporting date. For example, a common approach for valuing fixed income securities is the use of matrix pricing. Matrix pricing is a mathematical technique used to value securities by relying on the securities’ relationship to other benchmark quoted prices, and is considered a Level 2 input. Level 3: Unobservable inputs that are not supported by market data. Unobservable inputs are developed based on the best information available, which might include Teradyne’s own data. Teradyne’s available-for-sale fixed income securities are classified as Level 2. Contingent consideration is classified as Level 3. The vast majority of Level 2 securities are priced by third party pricing vendors. These pricing vendors utilize the most recent observable market information in pricing these securities or, if specific prices are not available, use other observable inputs like market transactions involving identical or comparable securities. Realized losses recorded in the nine months ended October 4, 2015 were $0.2 million. There were no realized losses recorded in the three and nine months ended September 28, 2014. Realized gains recorded in the three and nine months ended October 4, 2015 were $0.4 million and $1.4 million, respectively. Realized gains recorded in the three and nine months ended September 28, 2014 were $1.0 million and $1.7 million, respectively. Realized gains are included in interest income and realized losses are included in interest expense. Unrealized gains and losses are included in accumulated other comprehensive income (loss). The cost of securities sold is based on the specific identification method. During the nine months ended October 4, 2015 and September 28, 2014, there were no transfers in or out of Level 1, Level 2 or Level 3 financial instruments. The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of October 4, 2015 and December 31, 2014. October 4, 2015 Quoted Prices Significant Significant Total (in thousands) Assets Cash $ 159,858 $ — $ — $ 159,858 Cash equivalents 125,879 8,480 — 134,359 Available-for-sale securities: U.S. Treasury securities — 349,653 — 349,653 U.S. government agency securities — 213,491 — 213,491 Corporate debt securities — 114,807 — 114,807 Certificates of deposit and time deposits — 45,677 — 45,677 Commercial paper — 45,510 — 45,510 Equity and debt mutual funds 13,377 — — 13,377 Non-U.S. government securities — 426 — 426 Total $ 299,114 $ 778,044 $ — $ 1,077,158 Derivative assets — 109 — 109 Total $ 299,114 $ 778,153 $ — $ 1,077,267 Liabilities Contingent consideration $ — $ — $ 34,595 $ 34,595 Derivative liabilities — 97 — 97 Total $ — $ 97 $ 34,595 $ 34,692 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 285,737 $ 8,480 $ — $ 294,217 Marketable securities — 525,381 — 525,381 Long-term marketable securities 13,377 244,183 — 257,560 Prepayments — 109 — 109 $ 299,114 $ 778,153 $ — $ 1,077,267 Liabilities Other current liabilities $ — $ 97 $ — $ 97 Contingent consideration — — 14,447 14,447 Long-term contingent consideration — — 20,148 20,148 $ — $ 97 $ 34,595 $ 34,692 December 31, 2014 Quoted Prices Significant Significant Total (in thousands) Assets Cash $ 111,471 $ — $ — $ 111,471 Cash equivalents 160,218 22,567 — 182,785 Available-for-sale securities: U.S. Treasury securities — 402,154 — 402,154 U.S. government agency securities — 258,502 — 258,502 Corporate debt securities — 141,467 — 141,467 Commercial paper — 140,638 — 140,638 Certificates of deposit and time deposits — 49,036 — 49,036 Equity and debt mutual funds 12,333 — — 12,333 Non-U.S. government securities — 446 — 446 Total $ 284,022 $ 1,014,810 $ — $ 1,298,832 Derivative assets — 220 — 220 Total $ 284,022 $ 1,015,030 $ — $ 1,299,052 Liabilities Contingent consideration $ — $ — $ 3,350 $ 3,350 Derivative liabilities — 369 — 369 Total $ — $ 369 $ 3,350 $ 3,719 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 271,689 $ 22,567 $ — $ 294,256 Marketable securities — 533,787 — 533,787 Long-term marketable securities 12,333 458,456 — 470,789 Prepayments — 220 — 220 $ 284,022 $ 1,015,030 $ — $ 1,299,052 Liabilities Other current liabilities $ — $ 369 $ — 369 Contingent consideration — — 895 895 Long-term contingent consideration — — 2,455 2,455 $ — $ 369 $ 3,350 $ 3,719 Changes in the fair value of Level 3 contingent consideration for the three and nine months ended October 4, 2015 and September 28, 2014 were as follows: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 35,595 $ 2,230 $ 3,350 $ 2,230 Acquisition of Universal Robots — — 33,845 — Fair value adjustment(a)(b) (1,000 ) (630 ) (2,600 ) (630 ) Balance at end of period $ 34,595 $ 1,600 $ 34,595 $ 1,600 (a) In the three and nine months ended October 4, 2015, the fair value of contingent consideration for the earn-out in connection with the acquisition of AIT was reduced by $1.0 million due to a decrease in the revenue probabilities in the periods of 2015 and 2016. (b) In the nine months ended October 4, 2015, the fair value measurement of the contingent consideration for the earn-out in connection with the acquisition of ZTEC Instruments, Inc. was reduced by $1.6 million, to $0, because Teradyne and the Securityholder Representative, on behalf of the ZTEC securityholders, agreed to terminate the earn-out prior to the end of the December 31, 2015 earn-out period, with no payout in connection with the resolution of indemnity claims asserted by both Teradyne and the Securityholder Representative. The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instruments: Liability October 4, Valuation Unobservable Inputs Weighted (in thousands) Contingent consideration (Universal Robots) $33,845 Income approach- EBITDA earn-out for calendar year 2015 probability 99 % Discount rate 6.0 % Revenue earn-out for period July 1, 2015—December 31, 2017 probability 72 % Discount rate 8.0 % Revenue earn-out for period July 1, 2015—December 31, 2018 probability 29 % Discount rate 10.0 % Contingent consideration (AIT) $750 Income approach- Revenue earn-out for calendar years 2015 and 2016 probability 36 % Discount rate 4.7 % The significant unobservable inputs used in the Universal Robots fair value measurement of contingent consideration are the probabilities of successful achievement of revenue thresholds and targets in the periods July 1, 2015—December 31, 2017 and July 1, 2015—December 31, 2018 and EBITDA threshold and target for calendar year 2015, and respective discount rates. Increases or decreases in the revenue and EBITDA probabilities and the period in which results will be achieved would result in a higher or lower fair value measurement. The maximum amount of contingent consideration in connection with the acquisition of Universal Robots that could be paid is $65 million. The earn-out periods in connection with the Universal Robots acquisition end on December 31, 2015, December 31, 2017 and December 31, 2018. The significant unobservable inputs used in the AIT fair value measurement of contingent consideration are the probabilities of successful achievement of calendar year 2015 and 2016 revenue thresholds and targets, and a discount rate. Increases or decreases in the revenue probabilities and the period in which results will be achieved would result in a higher or lower fair value measurement. The maximum amount of contingent consideration in connection with the acquisition of AIT that could be paid is $2.1 million. The earn-out periods in connection with the AIT acquisition end on December 31, 2015 and December 31, 2016. In the three and nine months ended October 4, 2015, the fair value of contingent consideration for the earn-out in connection with the acquisition of AIT was reduced by $1.0 million due to a decrease in the revenue probabilities in the periods of 2015 and 2016. The carrying amounts and fair values of Teradyne’s financial instruments at October 4, 2015 and December 31, 2014 were as follows: October 4, 2015 December 31, 2014 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 294,217 $ 294,217 $ 294,256 $ 294,256 Marketable securities 782,941 782,941 1,004,576 1,004,576 Derivative assets 109 109 220 220 Liabilities Contingent consideration 34,595 34,595 3,350 3,350 Derivative liabilities 97 97 369 369 The fair values of accounts receivable, net and accounts payable approximate the carrying value due to the short-term nature of these instruments. The following tables summarize the composition of available-for-sale marketable securities at October 4, 2015 and December 31, 2014: October 4, 2015 Available-for-Sale Fair Market Cost Unrealized Unrealized Fair Market (in thousands) U.S. Treasury securities $ 349,464 $ 385 $ (196 ) $ 349,653 $ 19,260 U.S. government agency securities 213,149 342 — 213,491 — Corporate debt securities 115,130 1,305 (1,628 ) 114,807 48,369 Certificates of deposit and time deposits 45,652 25 — 45,677 3,505 Commercial paper 45,498 12 — 45,510 — Equity and debt mutual funds 12,291 1,183 (97 ) 13,377 1,900 Non-U.S. government securities 426 — — 426 — $ 781,610 $ 3,252 $ (1,921 ) $ 782,941 $ 73,034 Reported as follows: Cost Unrealized Unrealized Fair Market Fair Market (in thousands) Marketable securities $ 525,052 $ 335 $ (6 ) $ 525,381 $ 27,172 Long-term marketable securities 256,558 2,917 (1,915 ) 257,560 45,862 $ 781,610 $ 3,252 $ (1,921 ) $ 782,941 $ 73,034 December 31, 2014 Available-for-Sale Fair Market Cost Unrealized Unrealized Fair Market (in thousands) U.S. Treasury securities $ 402,197 $ 362 $ (405 ) $ 402,154 $ 317,771 U.S. government agency securities 258,452 135 (85 ) 258,502 104,642 Corporate debt securities 139,374 2,414 (321 ) 141,467 96,998 Commercial paper 140,616 26 (4 ) 140,638 41,747 Certificates of deposit and time deposits 49,048 11 (23 ) 49,036 20,684 Equity and debt mutual funds 10,492 1,870 (29 ) 12,333 1,234 Non-U.S. government securities 446 — — 446 — $ 1,000,625 $ 4,818 $ (867 ) $ 1,004,576 $ 583,076 Reported as follows: Cost Unrealized Unrealized Fair Market Fair Market (in thousands) Marketable securities $ 533,833 $ 99 $ (145 ) $ 533,787 $ 240,234 Long-term marketable securities 466,792 4,719 (722 ) 470,789 342,842 $ 1,000,625 $ 4,818 $ (867 ) $ 1,004,576 $ 583,076 As of October 4, 2015, unrealized losses on marketable securities were $1.9 million and the fair market value of investments with unrealized losses was $73.0 million. Of this value, $0.3 million had unrealized losses greater than one year and $72.7 million had unrealized losses less than one year. As of December 31, 2014, unrealized losses on marketable securities were $0.9 million and the fair market value of investments with unrealized losses was $583.1 million. Of this value, $2.3 million had unrealized losses greater than one year and $580.8 million had unrealized losses less than one year. Teradyne reviews its investments to identify and evaluate investments that have an indication of possible impairment. Based on this review, Teradyne determined that the unrealized losses related to these investments, at October 4, 2015 and December 31, 2014, were temporary. The contractual maturities of investments held at October 4, 2015 were as follows: October 4, 2015 Cost Fair Market (in thousands) Due within one year $ 525,052 $ 525,381 Due after 1 year through 5 years 199,957 200,305 Due after 5 years through 10 years 6,075 6,191 Due after 10 years 38,235 37,687 Total $ 769,319 $ 769,564 Contractual maturities of investments held at October 4, 2015 exclude equity and debt mutual funds as they do not have contractual maturity dates. Derivatives Teradyne conducts business in a number of foreign countries, with certain transactions denominated in local currencies. The purpose of Teradyne’s foreign currency management is to minimize the effect of exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities. Teradyne does not use derivative financial instruments for trading or speculative purposes. To minimize the effect of exchange rate fluctuations associated with the remeasurement of monetary assets and liabilities denominated in foreign currencies, Teradyne enters into foreign currency forward contracts. The change in fair value of these derivatives is recorded directly in earnings, and is used to offset the change in value of monetary assets and liabilities denominated in foreign currencies. The notional amount of foreign currency forward contracts was $91.5 million and $73.0 million at October 4, 2015 and December 31, 2014, respectively. The fair value of the outstanding contracts was $0.0 million and a loss of $0.1 million at October 4, 2015 and December 31, 2014, respectively. In the three and nine months ended October 4, 2015, Teradyne recorded a net realized loss of $0.8 million and $2.7 million, respectively, related to foreign currency forward contracts hedging net monetary positions. In the three months ended September 28, 2014, Teradyne recorded a net realized gain of $0.2 million related to foreign currency forward contracts hedging net monetary positions. In the nine months ended September 28, 2014, Teradyne recorded a net realized loss of $1.6 million related to foreign currency forward contracts hedging net monetary positions. Gains and losses on foreign currency forward contracts and foreign currency remeasurement gains and losses on monetary assets and liabilities are included in other (income) expense, net. The following table summarizes the fair value of derivative instruments at October 4, 2015 and December 31, 2014: Balance Sheet Location October 4, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts assets Prepayments $ 109 $ 220 Foreign exchange contracts liabilities Other current liabilities (97 ) (369 ) Total derivatives $ 12 $ (149 ) Teradyne’s foreign exchange contracts are subject to master netting agreements. The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three and nine months ended October 4, 2015 and September 28, 2014. The table does not reflect the corresponding gains and losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies. For the three and nine months ended October 4, 2015, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.1 million and $2.3 million, respectively. For the three months ended September 28, 2014, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.4 million. For the nine months ended September 28, 2014, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.9 million. Location of (Gains) Losses Statement of Operations For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 677 $ 237 $ 2,555 $ (1,632 ) Total Derivatives $ 677 $ 237 $ 2,555 $ (1,632 ) See Note F: “Debt” regarding derivatives related to the convertible senior notes.

Debt

Debt	9 Months Ended
	Oct. 04, 2015
Debt	F. Debt Revolving Credit Facility On April 27, 2015, Teradyne entered into a Credit Agreement (the “Credit Agreement”) with Barclays Bank PLC, as administrative agent and collateral agent, and the lenders party thereto. The Credit Agreement provides for a five-year, senior secured revolving credit facility of $350 million (the “Credit Facility”). The Credit Agreement further provides that, subject to customary conditions, Teradyne may seek to obtain from existing or new lenders incremental commitments under the Credit Facility in an aggregate principal amount not to exceed $150.0 million. Proceeds from the Credit Facility may be used for general corporate purposes and working capital. Teradyne incurred $2.3 million in costs related to the revolving credit facility. These costs are being amortized over the five year term of the revolving credit facility and are included in interest expense in the statement of operations. As of November 13, 2015, Teradyne has not borrowed any funds under the Credit Facility. The interest rates applicable to loans under the Credit Facility are, at Teradyne’s option, equal to either a base rate plus a margin ranging from 0.00% to 1.00% per annum or LIBOR plus a margin ranging from 1.00% to 2.00% per annum, based on the Consolidated Leverage Ratio of Teradyne and its Restricted Subsidiaries. In addition, Teradyne will pay a commitment fee on the unused portion of the commitments under the Credit Facility ranging from 0.125% to 0.350% per annum, based on the then applicable Consolidated Leverage Ratio. Teradyne is not required to repay any loans under the Credit Facility prior to maturity, subject to certain customary exceptions. Teradyne is permitted to prepay all or any portion of the loans under the Credit Facility prior to maturity without premium or penalty, other than customary LIBOR breakage costs. The Credit Agreement contains customary events of default, representations, warranties and affirmative and negative covenants that, among other things, limit Teradyne’s and its Restricted Subsidiaries’ ability to sell assets, grant liens on assets, incur other secured indebtedness and make certain investments and restricted payments, all subject to exceptions set forth in the Credit Agreement. The Credit Agreement also requires Teradyne to satisfy two financial ratios measured as of the end of each fiscal quarter: a consolidated leverage ratio and an interest coverage ratio. As of October 4, 2015, Teradyne was in compliance with all covenants. The Credit Facility is guaranteed by certain of Teradyne’s domestic subsidiaries and collateralized by assets of Teradyne and such subsidiaries, including a pledge of 65% of the capital stock of certain foreign subsidiaries. Convertible Senior Notes On March 31, 2009, Teradyne entered into an underwriting agreement regarding a public offering of $175.0 million aggregate principal amount of 4.50% convertible senior notes due March 15, 2014 (the “Notes”). On April 1, 2009, the underwriters exercised their option to purchase an additional $15.0 million aggregate principal amount of the Notes for a total aggregate principal amount of $190.0 million. The Notes bore interest at a rate of 4.50% per annum, payable semiannually in arrears on March 15 and September 15 of each year, beginning on September 15, 2009. The Notes had a maturity date of March 15, 2014. Substantially all of the Notes were converted prior to March 15, 2014 and were “net share settled,” meaning that the holders received, for each $1,000 in principal amount of Notes, $1,000 in cash and approximately 131.95 shares of Teradyne common stock (calculated by taking 182.65 shares, being the fixed number specified in the Notes purchase agreement, less 50.7 shares). The 50.7 shares were determined, as specified in the Notes purchase agreement, by dividing the $1,000 principal amount by the $19.74 average trading price of Teradyne’s common stock over the 25 day trading period from February 5, 2014 to March 12, 2014. Teradyne satisfied the Notes “net share settlement” by paying the aggregate principal amount of $190 million in cash and issuing 25.1 million shares of common stock. On March 13, 2014, Teradyne exercised its call option agreement entered into with Goldman, Sachs & Co. (the “hedge counterparty”) at the time of issuance of the Notes and received 25.1 million shares of Teradyne’s common stock, which Teradyne retired. From June 17, 2014 to September 17, 2014, the hedge counterparty exercised its warrant agreement entered into with Teradyne at the time of issuance of the Notes. The warrants were net share settled. In 2014, Teradyne issued 21.2 million shares of its common stock for warrants exercised at a weighted average strike price of $7.6348 per share. The interest expense on Teradyne’s convertible senior notes for the nine months ended October 4, 2015 and September 28, 2014 was as follows: For the Nine Months October 4, September 28, (in thousands) Contractual interest expense on the coupon $ — $ 1,757 Amortization of the discount component and debt issuance fees recognized as interest expense — 4,493 Total interest expense on the convertible debt $ — $ 6,250

Prepayments

Prepayments	9 Months Ended
	Oct. 04, 2015
Prepayments	G. Prepayments Prepayments consist of the following and are included in prepayments on the balance sheet: October 4, December 31, (in thousands) Contract manufacturer prepayments $ 55,624 $ 65,972 Prepaid maintenance and other services 6,642 7,343 Prepaid taxes 6,585 11,462 Other prepayments 11,928 11,042 Total prepayments $ 80,779 $ 95,819

Deferred Revenue and Customer A

Deferred Revenue and Customer Advances	9 Months Ended
	Oct. 04, 2015
Deferred Revenue and Customer Advances	H. Deferred Revenue and Customer Advances Deferred revenue and customer advances consist of the following and are included in short and long-term deferred revenue and customer advances on the balance sheet: October 4, December 31, (in thousands) Extended warranty $ 47,489 $ 43,300 Product maintenance and training 37,976 30,500 Customer advances 6,133 8,875 Undelivered elements and other 12,210 8,857 Total deferred revenue and customer advances $ 103,808 $ 91,532

Product Warranty

Product Warranty	9 Months Ended
	Oct. 04, 2015
Product Warranty	I. Product Warranty Teradyne generally provides a one-year warranty on its products, commencing upon installation, acceptance or shipment. A provision is recorded upon revenue recognition to cost of revenues for estimated warranty expense based on historical experience. Related costs are charged to the warranty accrual as incurred. The warranty balance below is included in other accrued liabilities on the balance sheet. For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 8,228 $ 9,073 $ 8,942 $ 6,660 Acquisition — — 372 — Accruals for warranties issued during the period 3,261 4,419 9,548 12,675 Adjustments related to pre-existing warranties (1,211 ) (559 ) (3,039 ) (1,000 ) Settlements made during the period (2,370 ) (2,982 ) (7,915 ) (8,384 ) Balance at end of period $ 7,908 $ 9,951 $ 7,908 $ 9,951 When Teradyne receives revenue for extended warranty beyond one year, it is deferred and recognized on a straight-line basis over the contract period. Related costs are expensed as incurred. The extended warranty balance below is included in short and long-term deferred revenue and customer advances on the balance sheet. For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 43,299 $ 40,052 $ 43,300 $ 34,909 Acquisition — — 699 — Deferral of new extended warranty revenue 10,442 9,896 22,818 24,218 Recognition of extended warranty deferred revenue (6,252 ) (6,451 ) (19,328 ) (15,630 ) Balance at end of period $ 47,489 $ 43,497 $ 47,489 $ 43,497

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Oct. 04, 2015
Stock-Based Compensation	J. Stock-Based Compensation Teradyne grants performance-based restricted stock units (“PRSUs”) to its executive officers with a performance metric based on relative total shareholder return (“TSR”). Teradyne’s three-year TSR performance will be measured against the Philadelphia Semiconductor Index, which consists of thirty companies in the semiconductor device and capital equipment industries. The final number of TSR PRSUs that vest will vary based upon the level of performance achieved from 200% of the target shares to 0% of the target shares. The TSR PRSUs will vest upon the three-year anniversary of the grant date. Beginning with PRSUs granted in January 2014, if the recipient’s employment ends prior to the determination of the performance percentage due to (1) permanent disability or death or (2) retirement or termination other than for cause, after attaining both at least age sixty and at least ten years of service, then all or a portion of the recipient’s PRSUs (based on the actual performance percentage achieved on the determination date) will vest on the date the performance percentage is determined. Except as set forth in the preceding sentence, no TSR PRSUs will vest if the executive officer is no longer an employee at the end of the three-year period. The TSR PRSUs are valued using a Monte Carlo simulation model. The number of units expected to be earned, based upon the achievement of the TSR market condition, is factored into the grant date Monte Carlo valuation. Compensation expense is recognized on a straight-line basis over the three-year service period. Compensation expense is recognized regardless of the eventual number of units that are earned based upon the market condition, provided the executive officer remains an employee at the end of the three-year period. Compensation expense is reversed if at any time during the three-year service period the executive officer is no longer an employee, subject to the retirement and termination eligibility provisions noted above. During the nine months ended October 4, 2015 and September 28, 2014, Teradyne granted 0.2 million and 0.1 million, TSR PRSUs, respectively, with a grant date fair value of $18.21 and $22.06, respectively. The fair value was estimated using the Monte Carlo simulation model with the following assumptions: For the Nine Months October 4, September 28, Risk-free interest rate 0.77 % 0.75 % Teradyne volatility-historical 28.2 % 36.1 % Philadelphia Semiconductor Index volatility-historical 19.7 % 24.6 % Dividend yield 1.33 % 1.25 % Expected volatility was based on the historical volatility of Teradyne’s stock and the Philadelphia Semiconductor Index over the most recent three year period. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.24 per share divided by Teradyne’s stock price on the grant date of $18.10 for 2015 grants and $19.16 for 2014 grants. During the nine months ended October 4, 2015, Teradyne granted 1.5 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $17.27 and 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $4.43. During the nine months ended September 28, 2014, Teradyne granted 1.7 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $19.09 and 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $5.49. Restricted stock unit awards granted to employees vest in equal annual installments over four years. Stock options vest in equal annual installments over four years and have a term of seven years from the date of grant. The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Nine Months October 4, September 28, Expected life (years) 4.0 4.0 Risk-free interest rate 1.1 % 1.2 % Volatility-historical 33.4 % 38.8 % Dividend yield 1.33 % 1.25 % Teradyne determined the stock options’ expected life based upon historical exercise data for executive officers, the age of the executive officers and the terms of the stock option grant. Volatility was determined using historical volatility for a period equal to the expected life. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.24 per share divided by Teradyne’s stock price on the grant date, of $18.10 for 2015 grants and $19.16 for 2014 grants. Effective January 31, 2014, Michael Bradley retired as Chief Executive Officer of Teradyne. On January 22, 2014, Teradyne entered into an agreement (the “Retirement Agreement”) with Mr. Bradley. Under the Retirement Agreement, Mr. Bradley’s unvested restricted stock units and stock options granted prior to his retirement date will continue to vest in accordance with their terms through January 31, 2017; and any vested options or options that vest during that period may be exercised for the remainder of the applicable option term. In the Retirement Agreement, Mr. Bradley agreed to be bound by non-competition and non-solicitation restrictions through January 31, 2017. Mr. Bradley continues to serve on Teradyne’s Board of Directors. In the three months ended March 30, 2014, Teradyne recorded a one-time charge to stock-based compensation expense of $6.6 million related to the Retirement Agreement.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	9 Months Ended
	Oct. 04, 2015
Accumulated Other Comprehensive Income	K. Accumulated Other Comprehensive Income Changes in accumulated other comprehensive income (loss), which is presented net of tax, consist of the following: For the Nine Months Ended October 4, 2015 Foreign Unrealized Securities Retirement Plans Prior Total (in thousands) Balance at December 31, 2014, net of tax of $1,598, $(453) $ — $ 2,365 $ 2,324 $ 4,689 Other comprehensive loss before reclassifications, net of tax of $0, $(896) (3,000 ) (593 ) — (3,593 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $(335), $(127) — (808 ) (221 ) (1,029 ) Net current period other comprehensive loss, net of tax of $0, $(1,231), $(127) (3,000 ) (1,401 ) (221 ) (4,622 ) Balance at October 4, 2015, net of tax of $0, $367, $(580) $ (3,000 ) $ 964 $ 2,103 $ 67 For the Nine Months Ended September 28, 2014 Unrealized Gains on Retirement Plans Prior Total (in thousands) Balance at December 31, 2013, net of tax of $794, $(284) $ 1,381 $ 2,619 $ 4,000 Other comprehensive income before reclassifications, net of tax of $1,103, $0 2,166 — 2,166 Amounts reclassified from accumulated other comprehensive income, net of tax of $(591), $(127) (1,086 ) (221 ) (1,307 ) Net current period other comprehensive income (loss), net of tax of $512, $(127) 1,080 (221 ) 859 Balance at September 28, 2014, net of tax of $1,306, $(411) $ 2,461 $ 2,398 $ 4,859 Reclassifications out of accumulated other comprehensive income to the statement of operations for the three and nine months ended October 4, 2015 and September 28, 2014, were as follows: Details about Accumulated Other Comprehensive Income Components For the Three Months For the Nine Affected Line Item October 4, September 28, October 4, September 28, (in thousands) Available-for-sale marketable securities: Unrealized gains, net of tax of $126, $348, $335, $591 $ 247 $ 638 $ 808 $ 1,086 Interest income Amortization of defined benefit pension and postretirement plans: Prior service benefit, net of tax of $42, $42, $127, $127 74 74 221 221 (a) Total reclassifications, net of tax of $168, $390, $462, $718 $ 321 $ 712 $ 1,029 $ 1,307 Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note O: “Retirement Plans.”

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Oct. 04, 2015
Goodwill and Intangible Assets	L. Goodwill and Intangible Assets The changes in the carrying amount of goodwill by reportable segments for the nine months ended October 4, 2015, were as follows: Wireless Industrial System Semiconductor Total (in thousands) Balance at December 31, 2014: Goodwill $ 361,819 $ — $ 158,699 $ 260,540 $ 781,058 Accumulated impairment losses (98,897 ) — (148,183 ) (260,540 ) (507,620 ) 262,922 — 10,516 — 273,438 Universal Robots acquisition — 226,501 — — 226,501 Universal Robots adjustment — 520 — — 520 Foreign currency translation adjustment — (2,113 ) — — (2,113 ) Balance at October 4, 2015: Goodwill 361,819 224,908 158,699 260,540 1,005,966 Accumulated impairment losses (98,897 ) — (148,183 ) (260,540 ) (507,620 ) $ 262,922 $ 224,908 $ 10,516 $ — $ 498,346 Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet: October 4, 2015 Gross Accumulated Net Weighted (in thousands) Developed technology $ 381,071 $ 206,256 $ 174,815 6.0 years Customer relationships 110,464 59,395 51,069 7.9 years Tradenames and trademarks 51,588 17,418 34,170 9.5 years Non-compete agreement 320 80 240 4.0 years Customer order backlog 170 170 — 0.3 years Total intangible assets $ 543,613 $ 283,319 $ 260,294 6.7 years December 31, 2014 Gross Accumulated Net Weighted (in thousands) Developed technology $ 345,513 $ 224,059 $ 121,454 6.2 years Customer relationships 146,635 93,998 52,637 7.7 years Tradenames and trademarks 30,414 14,205 16,209 9.0 years Non-compete agreement 320 20 300 4.0 years Customer order backlog 170 170 — 0.3 years Total intangible assets $ 523,052 $ 332,452 $ 190,600 6.8 years During the nine months ended October 4, 2015, Teradyne wrote off $98.2 million of fully amortized intangible assets. Aggregate intangible asset amortization expense was $20.1 million and $49.1 million, respectively, for the three and nine months ended October 4, 2015 and $18.3 million and $54.8 million, respectively, for the three and nine months ended September 28, 2014. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2015 (remainder) $ 20,029 2016 80,117 2017 71,498 2018 44,647 2019 23,785 Thereafter 20,218

Net Income per Common Share

Net Income per Common Share	9 Months Ended
	Oct. 04, 2015
Net Income per Common Share	M. Net Income per Common Share The following table sets forth the computation of basic and diluted net income per common share: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 71,453 $ 82,949 $ 207,118 $ 185,083 Weighted average common shares-basic 210,032 207,381 213,688 198,367 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) — — — 6,684 Convertible note hedge warrant shares (2) — 8,885 — 16,744 Restricted stock units 1,103 1,167 994 975 Stock options 578 879 626 997 Employee stock purchase plan 23 21 40 28 Dilutive potential common shares 1,704 10,952 1,660 25,428 Weighted average common shares-diluted 211,736 218,333 215,348 223,795 Net income per common share-basic $ 0.34 $ 0.40 $ 0.97 $ 0.93 Net income per common share-diluted $ 0.34 $ 0.38 $ 0.96 $ 0.83 (1) Incremental shares from the assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible note hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period. Teradyne’s call option on its common stock (convertible note hedge transaction) was excluded from the calculation of diluted shares because the effect was anti-dilutive. See Note F: “Debt” regarding the convertible note hedge transaction. The computation of diluted net income per common share for the three and nine months ended October 4, 2015 excludes the effect of the potential exercise of stock options to purchase approximately 0.2 million shares because the effect would have been anti-dilutive. The computation of diluted net income per common share for the three and nine months ended September 28, 2014 excludes the effect of the potential exercise of stock options to purchase approximately 0.3 million shares because the effect would have been anti-dilutive.

Restructuring and Other

Restructuring and Other	9 Months Ended
	Oct. 04, 2015
Restructuring and Other	N. Restructuring and Other Other During the three months ended October 4, 2015, Teradyne recorded a $1.0 million gain from the decrease in the fair value of the AIT contingent consideration liability, partially offset by $0.1 million of acquisition costs related to Universal Robots. During the nine months ended October 4, 2015, Teradyne recorded a $2.6 million gain from the decrease in the fair value of contingent consideration liability, of which $1.6 million was related to the ZTEC acquisition and $1.0 million was related to the AIT acquisition, partially offset by $1.1 million of acquisition costs related to Universal Robots. During the three and nine months ended September 28, 2014, Teradyne recorded a $0.6 million fair value adjustment to decrease the ZTEC acquisition contingent consideration. Restructuring During the three and nine months ended October 4, 2015, Teradyne recorded $1.1 million and $1.4 million, respectively, of severance charges related to headcount reductions of 18 and 22 people, respectively, primarily in System Test. During the nine months ended September 28, 2014, Teradyne recorded $0.8 million of severance charges related to headcount reductions of 30 people, primarily in Wireless Test.

Retirement Plans

Retirement Plans	9 Months Ended
	Oct. 04, 2015
Retirement Plans	O. Retirement Plans ASC 715, “Compensation—Retirement Benefits” Defined Benefit Pension Plans Teradyne has defined benefit pension plans covering a portion of domestic employees and employees of certain non-U.S. subsidiaries. Benefits under these plans are based on employees’ years of service and compensation. Teradyne’s funding policy is to make contributions to these plans in accordance with local laws and to the extent that such contributions are tax deductible. The assets of these plans consist primarily of fixed income and equity securities. In addition, Teradyne has an unfunded supplemental executive defined benefit plan in the United States to provide retirement benefits in excess of levels allowed by the Employment Retirement Income Security Act (“ERISA”) and the Internal Revenue Code (“IRC”), as well as unfunded foreign plans. In the nine months ended October 4, 2015, Teradyne contributed $1.9 million to the U.S. supplemental executive defined benefit pension plan and $0.6 million to certain qualified plans for non-U.S. subsidiaries. For the three and nine months ended October 4, 2015 and September 28, 2014, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended October 4, 2015 September 28, 2014 United Foreign United Foreign (in thousands) Service cost $ 616 $ 259 $ 555 $ 206 Interest cost 3,285 357 3,219 431 Expected return on plan assets (3,629 ) (185 ) (3,126 ) (209 ) Amortization of prior service cost 34 — 34 — Total net periodic pension cost $ 306 $ 431 $ 682 $ 428 For the Nine Months Ended October 4, 2015 September 28, 2014 United Foreign United Foreign (in thousands) Service cost $ 1,847 $ 768 $ 1,663 $ 705 Interest cost 9,856 1,101 9,656 1,446 Expected return on plan assets (10,888 ) (595 ) (9,375 ) (685 ) Amortization of prior service cost 101 — 101 — Actuarial (gain) loss (3 ) — 362 — Total net periodic pension cost $ 913 $ 1,274 $ 2,407 $ 1,466 Postretirement Benefit Plan In addition to receiving pension benefits, U.S. Teradyne employees who meet early retirement eligibility requirements as of their termination dates may participate in Teradyne’s Welfare Plan, which includes death, medical and dental benefits up to age 65. Death benefits provide a fixed sum to retirees’ survivors and are available to all retirees. Substantially all of Teradyne’s current U.S. employees could become eligible for these benefits, and the existing benefit obligation relates primarily to those employees. For the three and nine months ended October 4, 2015 and September 28, 2014, Teradyne’s net periodic postretirement benefit income was comprised of the following: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Service cost $ 12 $ 15 $ 36 $ 44 Interest cost 59 84 177 252 Amortization of prior service benefit (150 ) (150 ) (449 ) (449 ) Actuarial gain — — (19 ) (247 ) Total net periodic post-retirement benefit $ (79 ) $ (51 ) $ (255 ) $ (400 )

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Oct. 04, 2015
Commitments and Contingencies	P. Commitments and Contingencies Purchase Commitments As of October 4, 2015, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments covered by the agreements aggregate to approximately $219.6 million, of which $214.2 million is for less than one year. Legal Claims Teradyne is subject to various legal proceedings and claims which have arisen in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on Teradyne’s results of operations, financial condition or cash flows.

Income Taxes

Income Taxes	9 Months Ended
	Oct. 04, 2015
Income Taxes	Q. Income Taxes The effective tax rate for the three months ended October 4, 2015 and September 28, 2014 was 18.3% and 17.6%, respectively. The effective tax rates for these periods were lower than the expected federal statutory rate of 35% primarily because of the favorable effect of statutory rates applicable to income earned outside the United States. The tax rate for the three months ended October 4, 2015 was increased by additions to the uncertain tax positions for transfer pricing included in the projected annual effective tax rate, partially offset by $3.3 million of discrete tax benefits composed of $1.8 million of benefit attributable to a United States Tax Court opinion regarding intercompany cost sharing arrangements, $0.6 million of reductions in uncertain tax positions resulting from the expiration of statutes and $0.9 million from other discrete tax benefits. The tax rate for the three months ended September 28, 2014 was increased by $5.6 million of discrete tax expense composed of $7.2 million of additions to the uncertain tax positions for transfer pricing net of $0.9 million of discrete tax benefits resulting from increases in credit carry forwards and $0.7 million from other discrete tax benefits. The effective tax rate for the nine months ended October 4, 2015 and September 28, 2014 was 20.9% and 15.9%, respectively. The effective tax rates for these periods were lower than the expected federal statutory rate of 35% primarily because of the favorable effect of statutory rates applicable to income earned outside the United States. The tax rate for the nine months ended October 4, 2015 was increased by additions to the uncertain tax positions for transfer pricing included in the projected annual effective tax rate, partially offset by $5.0 million of discrete tax benefits composed of $1.8 million of benefit attributable to a United States Tax Court opinion regarding intercompany cost sharing arrangements, $1.3 million of reductions in uncertain tax positions resulting from the expiration of statutes and the settlement of an audit, $0.9 million from disqualifying dispositions of incentive stock options and employee stock purchase plan shares and $1.0 million from other discrete tax benefits. The tax rate for the nine months ended September 28, 2014 was increased by $2.6 million of discrete tax expense composed of $7.2 million of additions to the uncertain tax positions for transfer pricing net of $1.7 million of discrete tax benefits from disqualifying dispositions of incentive stock options and employee stock purchase plan shares, $0.9 million of discrete tax benefits resulting from increases in credit carry forwards and $2.0 million from other discrete tax benefits. On a quarterly basis, Teradyne evaluates the realizability of the deferred tax assets by jurisdiction and assesses the need for a valuation allowance. As of October 4, 2015, Teradyne believes that it will ultimately realize the deferred tax assets recorded on the condensed consolidated balance sheet. However, should Teradyne believe that it is more likely than not that the deferred tax assets would not be realized, the tax provision would increase in the period in which Teradyne determined that the realizability was not likely. Teradyne considers the probability of future taxable income and historical profitability, among other factors, in assessing the realizability of the deferred tax assets. As of October 4, 2015 and December 31, 2014, Teradyne had $33.3 million and $30.4 million, respectively, of reserves for uncertain tax positions. The $2.9 million net increase in reserves for uncertain tax positions relates primarily to transfer pricing exposures. As of October 4, 2015, Teradyne anticipated the liability for uncertain tax positions could decrease by approximately $0.1 million over the next twelve months, primarily as a result of the expiration of statutes of limitations. The potential decrease is related to transfer pricing exposures. Teradyne recognizes interest and penalties related to income tax matters in income tax expense. As of October 4, 2015 and December 31, 2014, $0.3 million and $0.6 million, respectively, of interest and penalties were included in the reserve for uncertain tax positions. Teradyne qualifies for a tax holiday in Singapore by fulfilling the requirements of an agreement with the Singapore Economic Development Board under which certain headcount and spending requirements must be met. The tax savings due to the tax holiday for the nine months ended October 4, 2015 was $9.9 million, or $0.05 per diluted share. The tax savings due to the tax holiday for the nine months ended September 28, 2014 was $12.3 million, or $0.05 per diluted share. The tax holiday is currently expected to expire on December 31, 2015. Teradyne is in discussion with the Singapore Economic Development Board with respect to extension of the tax holiday for periods after December 31, 2015.

Segment Information

Segment Information	9 Months Ended
	Oct. 04, 2015
Segment Information	R. Segment Information Teradyne has four operating segments (Semiconductor Test, Wireless Test, System Test and Industrial Automation), which are its reportable segments. The Semiconductor Test segment includes operations related to the design, manufacturing and marketing of semiconductor test products and services. The Wireless Test segment includes operations related to the design, manufacturing and marketing of wireless test products and services. The System Test segment includes operations related to the design, manufacturing and marketing of products and services for defense/aerospace instrumentation test, storage test and circuit-board test. The Industrial Automation segment includes operations related to the design, manufacturing and marketing of collaborative robots. Each operating segment has a segment manager who is directly accountable to and maintains regular contact with Teradyne’s chief operating decision maker (Teradyne’s chief executive officer) to discuss operating activities, financial results, forecasts, and plans for the segment. Teradyne evaluates performance based on several factors, of which the primary financial measure is business segment income before income taxes. The accounting policies of the business segments in effect are described in Note B: “Accounting Policies” in Teradyne’s Annual Report on Form 10-K for the year ended December 31, 2014, unless updated in this form 10-Q, where applicable. Segment information for the three and nine months ended October 4, 2015 and September 28, 2014 is as follows: Semiconductor Wireless System Industrial Corporate Consolidated (in thousands) Three months ended October 4, 2015: Revenues $ 325,516 $ 55,359 $ 69,062 $ 16,057 $ — $ 465,994 Income (loss) before income taxes (1)(2) 73,957 2,997 13,751 (4,847 ) 1,550 87,408 Total assets (3) 591,445 447,461 109,078 360,068 1,153,832 2,661,884 Three months ended September 28, 2014: Revenues $ 380,083 $ 54,838 $ 43,089 $ — $ — $ 478,010 Income before income taxes (1)(2) 91,900 2,379 5,779 — 612 100,670 Total assets (3) 748,499 614,911 83,769 — 1,247,828 2,695,007 Nine months ended October 4, 2015: Revenues $ 996,748 $ 152,285 $ 152,320 $ 19,780 $ — $ 1,321,133 Income (loss) before income taxes (1)(2) 246,627 (603 ) 10,423 (6,547 ) 12,081 261,981 Total assets (3) 591,445 447,461 109,078 360,068 1,153,832 2,661,884 Nine months ended September 28, 2014: Revenues $ 1,063,254 $ 144,747 $ 116,586 $ — $ — $ 1,324,587 Income (loss) before income taxes (1)(2) 233,770 (8,477 ) 5,512 — (10,616 ) 220,189 Total assets (3) 748,499 614,911 83,769 — 1,247,828 2,695,007 (1) Interest income, interest expense, and other (income) expense, net are included in Corporate and Eliminations. (2) Included in the income (loss) before income taxes for each of the segments are charges related to inventory and other. (3) Total business assets are directly attributable to each business. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets. Included in the Semiconductor Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Cost of revenues—inventory charge $ 1,697 $ 4,404 $ 8,637 $ 14,322 Restructuring and other 194 — 499 — Total $ 1,891 $ 4,404 $ 9,136 $ 14,322 Included in the Wireless Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory charge $ 901 $ 1,267 $ 2,077 $ 5,239 Restructuring and other — — — 426 Total $ 901 $ 1,267 $ 2,077 $ 5,665 Included in the System Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory charge $ 460 $ 763 $ 8,225 $ 1,944 Restructuring and other 923 225 923 371 Total $ 1,383 $ 988 $ 9,148 $ 2,315 Included in the Industrial Automation segment are charges in the following line item in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory step-up (1) $ 972 $ — $ 1,567 $ — Total $ 972 $ — $ 1,567 $ — Included in Corporate and Eliminations are charges and credits in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Restructuring and other—AIT contingent consideration adjustment $ (1,000 ) $ — $ (1,000 ) $ — Restructuring and other—Universal Robots acquisition costs 144 — 1,104 — Restructuring and other—ZTEC contingent consideration adjustment — (630 ) (1,600 ) (630 ) Other (income) expense, net—gain from the sale of an equity investment — — (5,406 ) — Selling and administrative—stock based compensation expense (2) — — — 6,598 Total $ (856 ) $ (630 ) $ (6,902 ) $ 5,968 (1) Included in the cost of revenues for the three and nine months ended October 4, 2015 is the cost for purchase accounting inventory step-up. (2) Expense related to the January 2014 retirement of Teradyne’s former chief executive officer; see Note J: “Stock-Based Compensation.”

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Oct. 04, 2015
Shareholders' Equity	S. Shareholders’ Equity Stock Repurchase Program In January 2015, the Board of Directors authorized Teradyne to repurchase up to $500 million of common stock, $300 million of which Teradyne intends to repurchase in 2015. The cumulative repurchases as of October 4, 2015 totaled 11.9 million shares of common stock for a total purchase price of $226.8 million at an average price per share of $19.09. The total price includes commissions and is recorded as a reduction to retained earnings. Dividend Holders of Teradyne’s common stock are entitled to receive dividends when they are declared by Teradyne’s Board of Directors. In January 2015, May 2015, and August 2015, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.06 per share. Dividend payments for the three and nine months ended October 4, 2015 were $12.6 million and $38.4 million, respectively. In January 2014 and August 2014, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.06 per share. Dividend payments for the three and nine months ended September 28, 2014 were $12.8 million and $24.4 million, respectively. While Teradyne declared a quarterly cash dividend and authorized a share repurchase program, it may reduce or eliminate the cash dividend or share repurchase program in the future. Future cash dividends and stock repurchases are subject to the discretion of Teradyne’s Board of Directors which will consider, among other things, Teradyne’s earnings, capital requirements and financial condition.

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Oct. 04, 2015
Basis of Presentation	Basis of Presentation The consolidated interim financial statements include the accounts of Teradyne and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated. These interim financial statements are unaudited and reflect all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of such interim financial statements. Certain prior year amounts were reclassified to conform to the current year presentation. The December 31, 2014 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 27, 2015, for the year ended December 31, 2014.
Preparation of Financial Statements and Use of Estimates	Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the amounts reported in the financial statements. Actual results may differ significantly from these estimates.
Revenue Recognition	Revenue Recognition Teradyne recognizes revenue when there is persuasive evidence of an arrangement, title and risk of loss have passed, delivery has occurred or the services have been rendered, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Title and risk of loss generally pass to Teradyne’s customers upon shipment or at delivery destination point. In circumstances where either title or risk of loss pass upon destination, acceptance or cash payment, Teradyne defers revenue recognition until such events occur except when title transfer is tied to cash payment outside the United States. Outside the United States, Teradyne recognizes revenue upon shipment or at delivery destination point, even if Teradyne retains a form of title to products delivered to customers, provided the sole purpose is to enable Teradyne to recover the products in the event of customer payment default and the arrangement does not prohibit the customer’s use or resale of the product in the ordinary course of business. Teradyne’s equipment has non-software and software components that function together to deliver the equipment’s essential functionality. Revenue is recognized upon shipment or at delivery destination point, provided that customer acceptance criteria can be demonstrated prior to shipment. Certain contracts require Teradyne to perform tests of the product to ensure that performance meets the published product specifications or customer requested specifications, which are generally conducted prior to shipment. Where the criteria cannot be demonstrated prior to shipment, revenue is deferred until customer acceptance has been received. Teradyne also defers the portion of the sales price that is not due until acceptance, which represents deferred profit. For multiple element arrangements, Teradyne allocates revenue to all deliverables based on their relative selling prices. In such circumstances, a hierarchy is used to determine the selling price for allocating revenue to deliverables as follows: (i) vendor-specific objective evidence of selling price (“VSOE”), (ii) third-party evidence of selling price (“TPE”), and (iii) best estimate of the selling price (“BESP”). For a delivered item to be considered a separate unit the delivered item must have value to the customer on a standalone basis and the delivery or performance of the undelivered item must be considered probable and substantially in Teradyne’s control. Teradyne’s post-shipment obligations include installation, training services, one-year standard warranties, and extended warranties. Installation does not alter the product capabilities, does not require specialized skills or tools and can be performed by the customers or other vendors. Installation is typically provided within five days of product shipment and is completed within one to two days thereafter. Training services are optional and do not affect the customers’ ability to use the product. Teradyne defers revenue for the selling price of installation and training. Extended warranties constitute warranty obligations beyond one year and Teradyne defers revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 605-20, “Separately Priced Extended Warranty and Product Maintenance Contracts” “Revenue Recognition Multiple-Element Arrangements.” Teradyne’s products are generally subject to warranty and related costs of the warranty are provided for in cost of revenue when product revenue is recognized. Teradyne classifies shipping and handling costs in cost of revenue. Teradyne generally does not provide its customers with contractual rights of return for any of its products.
Translation of Non-U.S. Currencies	Translation of Non-U.S. Currencies The functional currency for all non-U.S. subsidiaries is the U.S. dollar, except for the Industrial Automation segment for which the local currency is its functional currency. All foreign currency denominated monetary assets and liabilities are remeasured on a monthly basis into the functional currency using exchange rates in effect at the end of the period. All foreign currency denominated non-monetary assets and liabilities are remeasured into the functional currency using historical exchange rates. Net foreign exchange gains and losses resulting from remeasurement are included in other (income) expense, net. For Industrial Automation, assets and liabilities are translated into U.S. dollars using exchange rates in effect at the end of the period. Revenue and expense amounts are translated using an average of exchange rates in effect during the period. Translation adjustments are recorded within accumulated other comprehensive income (loss).

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Oct. 04, 2015
Avionics Interface Technologies, LLC
Allocation of Purchase Price	The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 10,516 Intangible assets 9,080 Tangible assets acquired and liabilities assumed: Current assets 2,452 Non-current assets 359 Accounts payable and current liabilities (1,164 ) Total purchase price $ 21,243
Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date	Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Customer relationships $ 5,630 5.0 Developed technology 2,580 4.8 Trademarks and tradenames 380 5.0 Non-compete agreement 320 4.0 Customer order backlog 170 0.3 Total intangible assets $ 9,080 4.8
Pro Forma Results Under Acquisitions	The unaudited pro forma results are not necessarily indicative of what actually would have occurred had the acquisition been in effect for the periods presented: For the Three Months For the Nine Months Ended September 28, 2014 October 4, September 28, Revenue $ 485,842 $ 1,339,181 $ 1,347,616 Net income 76,112 197,745 162,474 Net income per common share: Basic $ 0.37 $ 0.93 $ 0.82 Diluted $ 0.35 $ 0.92 $ 0.73
Universal Robots
Allocation of Purchase Price	The following table represents the preliminary allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 227,021 Intangible assets 119,950 Tangible assets acquired and liabilities assumed: Current assets 10,853 Non-current assets 3,415 Accounts payable and current liabilities (11,973 ) Long-term deferred tax liabilities (25,736 ) Long-term other liabilities (5,844 ) Total purchase price $317,686
Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date	Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 88,890 4.9 Trademarks and tradenames 21,680 10.0 Customer relationships 9,380 2.0 Total intangible assets $ 119,950 5.6

Financial Instruments and Der29

Financial Instruments and Derivatives (Tables)	9 Months Ended
	Oct. 04, 2015
Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of October 4, 2015 and December 31, 2014. October 4, 2015 Quoted Prices Significant Significant Total (in thousands) Assets Cash $ 159,858 $ — $ — $ 159,858 Cash equivalents 125,879 8,480 — 134,359 Available-for-sale securities: U.S. Treasury securities — 349,653 — 349,653 U.S. government agency securities — 213,491 — 213,491 Corporate debt securities — 114,807 — 114,807 Certificates of deposit and time deposits — 45,677 — 45,677 Commercial paper — 45,510 — 45,510 Equity and debt mutual funds 13,377 — — 13,377 Non-U.S. government securities — 426 — 426 Total $ 299,114 $ 778,044 $ — $ 1,077,158 Derivative assets — 109 — 109 Total $ 299,114 $ 778,153 $ — $ 1,077,267 Liabilities Contingent consideration $ — $ — $ 34,595 $ 34,595 Derivative liabilities — 97 — 97 Total $ — $ 97 $ 34,595 $ 34,692 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 285,737 $ 8,480 $ — $ 294,217 Marketable securities — 525,381 — 525,381 Long-term marketable securities 13,377 244,183 — 257,560 Prepayments — 109 — 109 $ 299,114 $ 778,153 $ — $ 1,077,267 Liabilities Other current liabilities $ — $ 97 $ — $ 97 Contingent consideration — — 14,447 14,447 Long-term contingent consideration — — 20,148 20,148 $ — $ 97 $ 34,595 $ 34,692 December 31, 2014 Quoted Prices Significant Significant Total (in thousands) Assets Cash $ 111,471 $ — $ — $ 111,471 Cash equivalents 160,218 22,567 — 182,785 Available-for-sale securities: U.S. Treasury securities — 402,154 — 402,154 U.S. government agency securities — 258,502 — 258,502 Corporate debt securities — 141,467 — 141,467 Commercial paper — 140,638 — 140,638 Certificates of deposit and time deposits — 49,036 — 49,036 Equity and debt mutual funds 12,333 — — 12,333 Non-U.S. government securities — 446 — 446 Total $ 284,022 $ 1,014,810 $ — $ 1,298,832 Derivative assets — 220 — 220 Total $ 284,022 $ 1,015,030 $ — $ 1,299,052 Liabilities Contingent consideration $ — $ — $ 3,350 $ 3,350 Derivative liabilities — 369 — 369 Total $ — $ 369 $ 3,350 $ 3,719 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 271,689 $ 22,567 $ — $ 294,256 Marketable securities — 533,787 — 533,787 Long-term marketable securities 12,333 458,456 — 470,789 Prepayments — 220 — 220 $ 284,022 $ 1,015,030 $ — $ 1,299,052 Liabilities Other current liabilities $ — $ 369 $ — 369 Contingent consideration — — 895 895 Long-term contingent consideration — — 2,455 2,455 $ — $ 369 $ 3,350 $ 3,719
Schedule of Changes in Fair Value of Level 3 Contingent Consideration	Changes in the fair value of Level 3 contingent consideration for the three and nine months ended October 4, 2015 and September 28, 2014 were as follows: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 35,595 $ 2,230 $ 3,350 $ 2,230 Acquisition of Universal Robots — — 33,845 — Fair value adjustment(a)(b) (1,000 ) (630 ) (2,600 ) (630 ) Balance at end of period $ 34,595 $ 1,600 $ 34,595 $ 1,600 (a) In the three and nine months ended October 4, 2015, the fair value of contingent consideration for the earn-out in connection with the acquisition of AIT was reduced by $1.0 million due to a decrease in the revenue probabilities in the periods of 2015 and 2016. (b) In the nine months ended October 4, 2015, the fair value measurement of the contingent consideration for the earn-out in connection with the acquisition of ZTEC Instruments, Inc. was reduced by $1.6 million, to $0, because Teradyne and the Securityholder Representative, on behalf of the ZTEC securityholders, agreed to terminate the earn-out prior to the end of the December 31, 2015 earn-out period, with no payout in connection with the resolution of indemnity claims asserted by both Teradyne and the Securityholder Representative.
Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument	The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instruments: Liability October 4, Valuation Unobservable Inputs Weighted (in thousands) Contingent consideration (Universal Robots) $33,845 Income approach- EBITDA earn-out for calendar year 2015 probability 99 % Discount rate 6.0 % Revenue earn-out for period July 1, 2015—December 31, 2017 probability 72 % Discount rate 8.0 % Revenue earn-out for period July 1, 2015—December 31, 2018 probability 29 % Discount rate 10.0 % Contingent consideration (AIT) $750 Income approach- Revenue earn-out for calendar years 2015 and 2016 probability 36 % Discount rate 4.7 %
Schedule of Carrying Amounts and Fair Values of Financial Instruments	The carrying amounts and fair values of Teradyne’s financial instruments at October 4, 2015 and December 31, 2014 were as follows: October 4, 2015 December 31, 2014 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 294,217 $ 294,217 $ 294,256 $ 294,256 Marketable securities 782,941 782,941 1,004,576 1,004,576 Derivative assets 109 109 220 220 Liabilities Contingent consideration 34,595 34,595 3,350 3,350 Derivative liabilities 97 97 369 369
Schedule of Available-for-Sale Marketable Securities	The following tables summarize the composition of available-for-sale marketable securities at October 4, 2015 and December 31, 2014: October 4, 2015 Available-for-Sale Fair Market Cost Unrealized Unrealized Fair Market (in thousands) U.S. Treasury securities $ 349,464 $ 385 $ (196 ) $ 349,653 $ 19,260 U.S. government agency securities 213,149 342 — 213,491 — Corporate debt securities 115,130 1,305 (1,628 ) 114,807 48,369 Certificates of deposit and time deposits 45,652 25 — 45,677 3,505 Commercial paper 45,498 12 — 45,510 — Equity and debt mutual funds 12,291 1,183 (97 ) 13,377 1,900 Non-U.S. government securities 426 — — 426 — $ 781,610 $ 3,252 $ (1,921 ) $ 782,941 $ 73,034 Reported as follows: Cost Unrealized Unrealized Fair Market Fair Market (in thousands) Marketable securities $ 525,052 $ 335 $ (6 ) $ 525,381 $ 27,172 Long-term marketable securities 256,558 2,917 (1,915 ) 257,560 45,862 $ 781,610 $ 3,252 $ (1,921 ) $ 782,941 $ 73,034 December 31, 2014 Available-for-Sale Fair Market Cost Unrealized Unrealized Fair Market (in thousands) U.S. Treasury securities $ 402,197 $ 362 $ (405 ) $ 402,154 $ 317,771 U.S. government agency securities 258,452 135 (85 ) 258,502 104,642 Corporate debt securities 139,374 2,414 (321 ) 141,467 96,998 Commercial paper 140,616 26 (4 ) 140,638 41,747 Certificates of deposit and time deposits 49,048 11 (23 ) 49,036 20,684 Equity and debt mutual funds 10,492 1,870 (29 ) 12,333 1,234 Non-U.S. government securities 446 — — 446 — $ 1,000,625 $ 4,818 $ (867 ) $ 1,004,576 $ 583,076 Reported as follows: Cost Unrealized Unrealized Fair Market Fair Market (in thousands) Marketable securities $ 533,833 $ 99 $ (145 ) $ 533,787 $ 240,234 Long-term marketable securities 466,792 4,719 (722 ) 470,789 342,842 $ 1,000,625 $ 4,818 $ (867 ) $ 1,004,576 $ 583,076
Contractual Maturities of Investments Held	The contractual maturities of investments held at October 4, 2015 were as follows: October 4, 2015 Cost Fair Market (in thousands) Due within one year $ 525,052 $ 525,381 Due after 1 year through 5 years 199,957 200,305 Due after 5 years through 10 years 6,075 6,191 Due after 10 years 38,235 37,687 Total $ 769,319 $ 769,564
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	The following table summarizes the fair value of derivative instruments at October 4, 2015 and December 31, 2014: Balance Sheet Location October 4, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts assets Prepayments $ 109 $ 220 Foreign exchange contracts liabilities Other current liabilities (97 ) (369 ) Total derivatives $ 12 $ (149 )
Schedule of Effect of Derivative Instruments on Statement of Operations Recognized	The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three and nine months ended October 4, 2015 and September 28, 2014. The table does not reflect the corresponding gains and losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies. For the three and nine months ended October 4, 2015, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.1 million and $2.3 million, respectively. For the three months ended September 28, 2014, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.4 million. For the nine months ended September 28, 2014, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.9 million. Location of (Gains) Losses Statement of Operations For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 677 $ 237 $ 2,555 $ (1,632 ) Total Derivatives $ 677 $ 237 $ 2,555 $ (1,632 )

Debt (Tables)

Debt (Tables)	9 Months Ended
	Oct. 04, 2015
Interest Expense on Convertible Senior Notes	The interest expense on Teradyne’s convertible senior notes for the nine months ended October 4, 2015 and September 28, 2014 was as follows: For the Nine Months October 4, September 28, (in thousands) Contractual interest expense on the coupon $ — $ 1,757 Amortization of the discount component and debt issuance fees recognized as interest expense — 4,493 Total interest expense on the convertible debt $ — $ 6,250

Prepayments (Tables)

Prepayments (Tables)	9 Months Ended
	Oct. 04, 2015
Schedule of Prepayments	Prepayments consist of the following and are included in prepayments on the balance sheet: October 4, December 31, (in thousands) Contract manufacturer prepayments $ 55,624 $ 65,972 Prepaid maintenance and other services 6,642 7,343 Prepaid taxes 6,585 11,462 Other prepayments 11,928 11,042 Total prepayments $ 80,779 $ 95,819

Deferred Revenue and Customer32

Deferred Revenue and Customer Advances (Tables)	9 Months Ended
	Oct. 04, 2015
Deferred Revenue and Customer Advances	Deferred revenue and customer advances consist of the following and are included in short and long-term deferred revenue and customer advances on the balance sheet: October 4, December 31, (in thousands) Extended warranty $ 47,489 $ 43,300 Product maintenance and training 37,976 30,500 Customer advances 6,133 8,875 Undelivered elements and other 12,210 8,857 Total deferred revenue and customer advances $ 103,808 $ 91,532

Product Warranty (Tables)

Product Warranty (Tables)	9 Months Ended
	Oct. 04, 2015
Other Accrued Liabilities	The warranty balance below is included in other accrued liabilities on the balance sheet. For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 8,228 $ 9,073 $ 8,942 $ 6,660 Acquisition — — 372 — Accruals for warranties issued during the period 3,261 4,419 9,548 12,675 Adjustments related to pre-existing warranties (1,211 ) (559 ) (3,039 ) (1,000 ) Settlements made during the period (2,370 ) (2,982 ) (7,915 ) (8,384 ) Balance at end of period $ 7,908 $ 9,951 $ 7,908 $ 9,951
Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances	The extended warranty balance below is included in short and long-term deferred revenue and customer advances on the balance sheet. For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Balance at beginning of period $ 43,299 $ 40,052 $ 43,300 $ 34,909 Acquisition — — 699 — Deferral of new extended warranty revenue 10,442 9,896 22,818 24,218 Recognition of extended warranty deferred revenue (6,252 ) (6,451 ) (19,328 ) (15,630 ) Balance at end of period $ 47,489 $ 43,497 $ 47,489 $ 43,497

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Oct. 04, 2015
Schedule of Estimated Fair Value TSR Performance-Based Restricted Stock Unit Awards Assumptions	The fair value was estimated using the Monte Carlo simulation model with the following assumptions: For the Nine Months October 4, September 28, Risk-free interest rate 0.77 % 0.75 % Teradyne volatility-historical 28.2 % 36.1 % Philadelphia Semiconductor Index volatility-historical 19.7 % 24.6 % Dividend yield 1.33 % 1.25 %
Stock Options
Fair Value of Stock Options Using Assumptions	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Nine Months October 4, September 28, Expected life (years) 4.0 4.0 Risk-free interest rate 1.1 % 1.2 % Volatility-historical 33.4 % 38.8 % Dividend yield 1.33 % 1.25 %

Accumulated Other Comprehensi35

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Oct. 04, 2015
Changes in Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive income (loss), which is presented net of tax, consist of the following: For the Nine Months Ended October 4, 2015 Foreign Unrealized Securities Retirement Plans Prior Total (in thousands) Balance at December 31, 2014, net of tax of $1,598, $(453) $ — $ 2,365 $ 2,324 $ 4,689 Other comprehensive loss before reclassifications, net of tax of $0, $(896) (3,000 ) (593 ) — (3,593 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $(335), $(127) — (808 ) (221 ) (1,029 ) Net current period other comprehensive loss, net of tax of $0, $(1,231), $(127) (3,000 ) (1,401 ) (221 ) (4,622 ) Balance at October 4, 2015, net of tax of $0, $367, $(580) $ (3,000 ) $ 964 $ 2,103 $ 67 For the Nine Months Ended September 28, 2014 Unrealized Gains on Retirement Plans Prior Total (in thousands) Balance at December 31, 2013, net of tax of $794, $(284) $ 1,381 $ 2,619 $ 4,000 Other comprehensive income before reclassifications, net of tax of $1,103, $0 2,166 — 2,166 Amounts reclassified from accumulated other comprehensive income, net of tax of $(591), $(127) (1,086 ) (221 ) (1,307 ) Net current period other comprehensive income (loss), net of tax of $512, $(127) 1,080 (221 ) 859 Balance at September 28, 2014, net of tax of $1,306, $(411) $ 2,461 $ 2,398 $ 4,859
Reclassifications Out of Accumulated Other Comprehensive Income to Statement of Operations	Reclassifications out of accumulated other comprehensive income to the statement of operations for the three and nine months ended October 4, 2015 and September 28, 2014, were as follows: Details about Accumulated Other Comprehensive Income Components For the Three Months For the Nine Affected Line Item October 4, September 28, October 4, September 28, (in thousands) Available-for-sale marketable securities: Unrealized gains, net of tax of $126, $348, $335, $591 $ 247 $ 638 $ 808 $ 1,086 Interest income Amortization of defined benefit pension and postretirement plans: Prior service benefit, net of tax of $42, $42, $127, $127 74 74 221 221 (a) Total reclassifications, net of tax of $168, $390, $462, $718 $ 321 $ 712 $ 1,029 $ 1,307 Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note O: “Retirement Plans.”

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Oct. 04, 2015
Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by reportable segments for the nine months ended October 4, 2015, were as follows: Wireless Industrial System Semiconductor Total (in thousands) Balance at December 31, 2014: Goodwill $ 361,819 $ — $ 158,699 $ 260,540 $ 781,058 Accumulated impairment losses (98,897 ) — (148,183 ) (260,540 ) (507,620 ) 262,922 — 10,516 — 273,438 Universal Robots acquisition — 226,501 — — 226,501 Universal Robots adjustment — 520 — — 520 Foreign currency translation adjustment — (2,113 ) — — (2,113 ) Balance at October 4, 2015: Goodwill 361,819 224,908 158,699 260,540 1,005,966 Accumulated impairment losses (98,897 ) — (148,183 ) (260,540 ) (507,620 ) $ 262,922 $ 224,908 $ 10,516 $ — $ 498,346
Schedule of Amortizable Intangible Assets	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet: October 4, 2015 Gross Accumulated Net Weighted (in thousands) Developed technology $ 381,071 $ 206,256 $ 174,815 6.0 years Customer relationships 110,464 59,395 51,069 7.9 years Tradenames and trademarks 51,588 17,418 34,170 9.5 years Non-compete agreement 320 80 240 4.0 years Customer order backlog 170 170 — 0.3 years Total intangible assets $ 543,613 $ 283,319 $ 260,294 6.7 years December 31, 2014 Gross Accumulated Net Weighted (in thousands) Developed technology $ 345,513 $ 224,059 $ 121,454 6.2 years Customer relationships 146,635 93,998 52,637 7.7 years Tradenames and trademarks 30,414 14,205 16,209 9.0 years Non-compete agreement 320 20 300 4.0 years Customer order backlog 170 170 — 0.3 years Total intangible assets $ 523,052 $ 332,452 $ 190,600 6.8 years
Schedule of Estimated Intangible Asset Amortization Expense	Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2015 (remainder) $ 20,029 2016 80,117 2017 71,498 2018 44,647 2019 23,785 Thereafter 20,218

Net Income per Common Share (Ta

Net Income per Common Share (Tables)	9 Months Ended
	Oct. 04, 2015
Computation of Basic and Diluted Net Income Per Common Share	The following table sets forth the computation of basic and diluted net income per common share: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 71,453 $ 82,949 $ 207,118 $ 185,083 Weighted average common shares-basic 210,032 207,381 213,688 198,367 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) — — — 6,684 Convertible note hedge warrant shares (2) — 8,885 — 16,744 Restricted stock units 1,103 1,167 994 975 Stock options 578 879 626 997 Employee stock purchase plan 23 21 40 28 Dilutive potential common shares 1,704 10,952 1,660 25,428 Weighted average common shares-diluted 211,736 218,333 215,348 223,795 Net income per common share-basic $ 0.34 $ 0.40 $ 0.97 $ 0.93 Net income per common share-diluted $ 0.34 $ 0.38 $ 0.96 $ 0.83 (1) Incremental shares from the assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible note hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period. Teradyne’s call option on its common stock (convertible note hedge transaction) was excluded from the calculation of diluted shares because the effect was anti-dilutive. See Note F: “Debt” regarding the convertible note hedge transaction.

Retirement Plans (Tables)

Retirement Plans (Tables)	9 Months Ended
	Oct. 04, 2015
Postretirement Benefit Plans
Net Periodic Pension and Postretirement Benefit Income Costs	For the three and nine months ended October 4, 2015 and September 28, 2014, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended October 4, 2015 September 28, 2014 United Foreign United Foreign (in thousands) Service cost $ 616 $ 259 $ 555 $ 206 Interest cost 3,285 357 3,219 431 Expected return on plan assets (3,629 ) (185 ) (3,126 ) (209 ) Amortization of prior service cost 34 — 34 — Total net periodic pension cost $ 306 $ 431 $ 682 $ 428 For the Nine Months Ended October 4, 2015 September 28, 2014 United Foreign United Foreign (in thousands) Service cost $ 1,847 $ 768 $ 1,663 $ 705 Interest cost 9,856 1,101 9,656 1,446 Expected return on plan assets (10,888 ) (595 ) (9,375 ) (685 ) Amortization of prior service cost 101 — 101 — Actuarial (gain) loss (3 ) — 362 — Total net periodic pension cost $ 913 $ 1,274 $ 2,407 $ 1,466
Defined Benefit Pension Plans
Net Periodic Pension and Postretirement Benefit Income Costs	For the three and nine months ended October 4, 2015 and September 28, 2014, Teradyne’s net periodic postretirement benefit income was comprised of the following: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Service cost $ 12 $ 15 $ 36 $ 44 Interest cost 59 84 177 252 Amortization of prior service benefit (150 ) (150 ) (449 ) (449 ) Actuarial gain — — (19 ) (247 ) Total net periodic post-retirement benefit $ (79 ) $ (51 ) $ (255 ) $ (400 )

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Oct. 04, 2015
Segment Information	Segment information for the three and nine months ended October 4, 2015 and September 28, 2014 is as follows: Semiconductor Wireless System Industrial Corporate Consolidated (in thousands) Three months ended October 4, 2015: Revenues $ 325,516 $ 55,359 $ 69,062 $ 16,057 $ — $ 465,994 Income (loss) before income taxes (1)(2) 73,957 2,997 13,751 (4,847 ) 1,550 87,408 Total assets (3) 591,445 447,461 109,078 360,068 1,153,832 2,661,884 Three months ended September 28, 2014: Revenues $ 380,083 $ 54,838 $ 43,089 $ — $ — $ 478,010 Income before income taxes (1)(2) 91,900 2,379 5,779 — 612 100,670 Total assets (3) 748,499 614,911 83,769 — 1,247,828 2,695,007 Nine months ended October 4, 2015: Revenues $ 996,748 $ 152,285 $ 152,320 $ 19,780 $ — $ 1,321,133 Income (loss) before income taxes (1)(2) 246,627 (603 ) 10,423 (6,547 ) 12,081 261,981 Total assets (3) 591,445 447,461 109,078 360,068 1,153,832 2,661,884 Nine months ended September 28, 2014: Revenues $ 1,063,254 $ 144,747 $ 116,586 $ — $ — $ 1,324,587 Income (loss) before income taxes (1)(2) 233,770 (8,477 ) 5,512 — (10,616 ) 220,189 Total assets (3) 748,499 614,911 83,769 — 1,247,828 2,695,007 (1) Interest income, interest expense, and other (income) expense, net are included in Corporate and Eliminations. (2) Included in the income (loss) before income taxes for each of the segments are charges related to inventory and other. (3) Total business assets are directly attributable to each business. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.
Semiconductor Test
Schedule of Segment Reporting Information by Segment Charges	Included in the Semiconductor Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, September 28, October 4, September 28, (in thousands) Cost of revenues—inventory charge $ 1,697 $ 4,404 $ 8,637 $ 14,322 Restructuring and other 194 — 499 — Total $ 1,891 $ 4,404 $ 9,136 $ 14,322
Wireless Test
Schedule of Segment Reporting Information by Segment Charges	Included in the Wireless Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory charge $ 901 $ 1,267 $ 2,077 $ 5,239 Restructuring and other — — — 426 Total $ 901 $ 1,267 $ 2,077 $ 5,665
System Test
Schedule of Segment Reporting Information by Segment Charges	Included in the System Test segment are charges in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory charge $ 460 $ 763 $ 8,225 $ 1,944 Restructuring and other 923 225 923 371 Total $ 1,383 $ 988 $ 9,148 $ 2,315
Industrial Automation
Schedule of Segment Reporting Information by Segment Charges	Included in the Industrial Automation segment are charges in the following line item in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Cost of revenues—inventory step-up (1) $ 972 $ — $ 1,567 $ — Total $ 972 $ — $ 1,567 $ —
Corporate And Eliminations
Schedule of Segment Reporting Information by Segment Charges	Included in Corporate and Eliminations are charges and credits in the following line items in the statements of operations: For the Three Months For the Nine Months October 4, 2015 September 28, 2014 October 4, 2015 September 28, 2014 (in thousands) Restructuring and other—AIT contingent consideration adjustment $ (1,000 ) $ — $ (1,000 ) $ — Restructuring and other—Universal Robots acquisition costs 144 — 1,104 — Restructuring and other—ZTEC contingent consideration adjustment — (630 ) (1,600 ) (630 ) Other (income) expense, net—gain from the sale of an equity investment — — (5,406 ) — Selling and administrative—stock based compensation expense (2) — — — 6,598 Total $ (856 ) $ (630 ) $ (6,902 ) $ 5,968 (1) Included in the cost of revenues for the three and nine months ended October 4, 2015 is the cost for purchase accounting inventory step-up. (2) Expense related to the January 2014 retirement of Teradyne’s former chief executive officer; see Note J: “Stock-Based Compensation.”

The Company - Additional inform

The Company - Additional information (Detail) - Universal Robots	Jun. 11, 2015USD ($)
Business Acquisition [Line Items]
Cash paid to acquire outstanding common and preferred stock	$ 283,900,000
Arrangement range of outcomes value high	$ 65,000,000

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($)		Jun. 11, 2015	Oct. 31, 2014	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
Contingent consideration				$ 14,447,000		$ 14,447,000	$ 14,447,000		$ 895,000
Revenues				465,994,000	$ 478,010,000		1,321,133,000	$ 1,324,587,000
Income (loss) before income taxes	[1],[2]			87,408,000	100,670,000		261,981,000	220,189,000
Net income					$ 76,112,000		197,745,000	162,474,000
Contingent consideration adjustment							(2,600,000)	(630,000)
Avionics Interface Technologies, LLC
Business Acquisition [Line Items]
Total purchase price			$ 21,243,000
Cash paid to acquire outstanding common and preferred stock			19,400,000
Contingent consideration			1,800,000
Arrangement range of outcomes value high			$ 2,100,000
Discount rate			4.70%
Contingent consideration adjustment				(1,000,000)			(1,000,000)
Goodwill, expected tax deduction			$ 10,500,000
Universal Robots
Business Acquisition [Line Items]
Total purchase price		$ 317,686,000
Cash paid to acquire outstanding common and preferred stock		283,900,000
Contingent consideration		33,800,000
Arrangement range of outcomes value high		65,000,000
Goodwill, not deductible for tax purposes		$ 227,000,000
Revenues				16,100,000		19,800,000
Income (loss) before income taxes				$ (4,800,000)		$ (6,500,000)
Universal Robots | Fair Value Adjustment to Inventory
Business Acquisition [Line Items]
Net income							(1,600,000)	1,600,000
Universal Robots | Acquisition Related Costs
Business Acquisition [Line Items]
Net income							$ (1,000,000)	$ 1,000,000
Universal Robots | Discount Rate One
Business Acquisition [Line Items]
Discount rate		6.00%
Universal Robots | Discount Rate Two
Business Acquisition [Line Items]
Discount rate		8.00%
Universal Robots | Discount Rate Three
Business Acquisition [Line Items]
Discount rate		10.00%
[1]	Included in the income (loss) before income taxes for each of the segments are charges related to inventory and other.
[2]	Interest income, interest expense, and other (income) expense, net are included in Corporate and Eliminations.

Allocation of Final Purchase Pr

Allocation of Final Purchase Price (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Jun. 11, 2015	Dec. 31, 2014	Oct. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 498,346		$ 273,438
Avionics Interface Technologies, LLC
Business Acquisition [Line Items]
Goodwill				$ 10,516
Intangible assets				9,080
Current assets				2,452
Non-current assets				359
Accounts payable and current liabilities				(1,164)
Total purchase price				$ 21,243
Universal Robots
Business Acquisition [Line Items]
Goodwill		$ 227,021
Intangible assets		119,950
Current assets		10,853
Non-current assets		3,415
Accounts payable and current liabilities		(11,973)
Long-term deferred tax liabilities		(25,736)
Long-term other liabilities		(5,844)
Total purchase price		$ 317,686

Components of Intangible Assets

Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date (Detail) - USD ($) $ in Thousands	Jun. 11, 2015	Oct. 31, 2014
Avionics Interface Technologies, LLC
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 9,080
Total intangible assets, estimated useful life, years		4 years 9 months 18 days
Avionics Interface Technologies, LLC | Customer Relationships
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 5,630
Total intangible assets, estimated useful life, years		5 years
Avionics Interface Technologies, LLC | Developed technology
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 2,580
Total intangible assets, estimated useful life, years		4 years 9 months 18 days
Avionics Interface Technologies, LLC | Trademarks and tradenames
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 380
Total intangible assets, estimated useful life, years		5 years
Avionics Interface Technologies, LLC | Non-compete Agreements
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 320
Total intangible assets, estimated useful life, years		4 years
Avionics Interface Technologies, LLC | Customer order backlog
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 170
Total intangible assets, estimated useful life, years		3 months 18 days
Universal Robots
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 119,950
Total intangible assets, estimated useful life, years	5 years 7 months 6 days
Universal Robots | Customer Relationships
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 9,380
Total intangible assets, estimated useful life, years	2 years
Universal Robots | Developed technology
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 88,890
Total intangible assets, estimated useful life, years	4 years 10 months 24 days
Universal Robots | Trademarks and tradenames
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 21,680
Total intangible assets, estimated useful life, years	10 years

Pro Forma Results Under Acquisi

Pro Forma Results Under Acquisition (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Business Acquisition [Line Items]
Revenue	$ 485,842	$ 1,339,181	$ 1,347,616
Net income	$ 76,112	$ 197,745	$ 162,474
Net income per common share, basic	$ 0.37	$ 0.93	$ 0.82
Net income per common share, diluted	$ 0.35	$ 0.92	$ 0.73

Financial Instruments and Der45

Financial Instruments and Derivatives - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014	Jun. 11, 2015	Oct. 31, 2014	Dec. 31, 2013
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized loss		$ 0	$ 200,000	$ 0
Available-for-sale securities, realized gain	$ 400,000	1,000,000	1,400,000	1,700,000
Contingent consideration	14,447,000		14,447,000		$ 895,000
Contingent consideration adjustment			(2,600,000)	(630,000)
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	73,034,000		73,034,000		583,076,000
Fair market value of investments with unrealized losses greater than one year	300,000		300,000		2,300,000
Fair market value of investments with unrealized losses less than one year	72,700,000		72,700,000		580,800,000
Available-for-sale marketable securities, Unrealized (Loss)	(1,921,000)		(1,921,000)		(867,000)
Gains (losses) on foreign currency transactions	100,000	(400,000)	2,300,000	900,000
Realized gain(loss) on foreign currency contracts	(800,000)	$ 200,000	(2,700,000)	$ (1,600,000)
AIT | Maximum
Financial Instruments and Fair Value [Line Items]
Contingent consideration							$ 2,100,000
Universal Robots
Financial Instruments and Fair Value [Line Items]
Contingent consideration						$ 33,800,000
Universal Robots | Maximum
Financial Instruments and Fair Value [Line Items]
Contingent consideration								$ 65,000,000
Avionics Interface Technologies, LLC
Financial Instruments and Fair Value [Line Items]
Contingent consideration							$ 1,800,000
Contingent consideration adjustment	(1,000,000)		(1,000,000)
Foreign Currency Forward Contracts
Financial Instruments and Fair Value [Line Items]
Notional amount of foreign currency forward contracts	$ 91,500,000		91,500,000		73,000,000
Gains (losses) on foreign currency transactions			$ 0		$ (100,000)

Schedule of Fair Value of Finan

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 782,941	$ 1,004,576
Contingent consideration	14,447	895
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	349,653	402,154
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	213,491	258,502
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	114,807	141,467
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,510	140,638
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,677	49,036
Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	13,377	12,333
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	426	446
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	1,077,158	1,298,832
Derivative assets	109	220
Total	1,077,267	1,299,052
Contingent consideration	34,595	3,350
Derivative liabilities	97	369
Total	34,692	3,719
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	159,858	111,471
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	134,359	182,785
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	349,653	402,154
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	213,491	258,502
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	114,807	141,467
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,510	140,638
Fair Value, Measurements, Recurring | Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,677	49,036
Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	13,377	12,333
Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	426	446
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	299,114	284,022
Total	299,114	284,022
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	159,858	111,471
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	125,879	160,218
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	13,377	12,333
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	778,044	1,014,810
Derivative assets	109	220
Total	778,153	1,015,030
Derivative liabilities	97	369
Total	97	369
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	8,480	22,567
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	349,653	402,154
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	213,491	258,502
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	114,807	141,467
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,510	140,638
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	45,677	49,036
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	426	446
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration	34,595	3,350
Total	$ 34,595	$ 3,350

Schedule of Reported Financial

Schedule of Reported Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 1,077,267	$ 1,299,052
Liabilities	34,692	3,719
Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	97	369
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	294,217	294,256
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	525,381	533,787
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	257,560	470,789
Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	109	220
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	14,447	895
Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	20,148	2,455
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	299,114	284,022
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	285,737	271,689
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	13,377	12,333
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	778,153	1,015,030
Liabilities	97	369
Significant Other Observable Inputs (Level 2) | Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	97	369
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	8,480	22,567
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	525,381	533,787
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	244,183	458,456
Significant Other Observable Inputs (Level 2) | Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	109	220
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	34,595	3,350
Significant Unobservable Inputs (Level 3) | Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	14,447	895
Significant Unobservable Inputs (Level 3) | Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	$ 20,148	$ 2,455

Schedule of Changes in Fair Val

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period		$ 35,595	$ 2,230	$ 3,350	$ 2,230
Fair value adjustment	[1],[2]	(1,000)	(630)	(2,600)	(630)
Ending Balance		$ 34,595	$ 1,600	34,595	$ 1,600
Universal Robots
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition				$ 33,845
[1]	In the nine months ended October 4, 2015, the fair value measurement of the contingent consideration for the earn-out in connection with the acquisition of ZTEC Instruments, Inc. was reduced by $1.6 million, to $0, because Teradyne and the Securityholder Representative, on behalf of the ZTEC securityholders, agreed to terminate the earn-out prior to the end of the December 31, 2015 earn-out period, with no payout in connection with the resolution of indemnity claims asserted by both Teradyne and the Securityholder Representative.
[2]	In the three and nine months ended October 4, 2015, the fair value of contingent consideration for the earn-out in connection with the acquisition of AIT was reduced by $1.0 million due to a decrease in the revenue probabilities in the periods of 2015 and 2016.

Schedule of Changes in Fair V49

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014	Oct. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business combination, contingent consideration reduced amount			$ (2,600)	$ (630)
Contingent consideration	$ 14,447		14,447		$ 895
Avionics Interface Technologies, LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business combination, contingent consideration reduced amount	(1,000)		(1,000)
Contingent consideration						$ 1,800
ZTEC Instruments, Inc.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business combination, contingent consideration reduced amount		$ (600)	(1,600)	$ (600)
Contingent consideration	$ 0		$ 0

Quantitative Information Associ

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail) - USD ($) $ in Thousands	Oct. 31, 2014	Oct. 04, 2015	Jun. 11, 2015	Dec. 31, 2014
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 14,447		$ 895
Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration			$ 33,800
Avionics Interface Technologies, LLC
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration	$ 1,800
Discount rate	4.70%
Significant Unobservable Inputs (Level 3) | Income Approach Valuation Technique | Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		33,845
Significant Unobservable Inputs (Level 3) | Income Approach Valuation Technique | Avionics Interface Technologies, LLC
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 750
Ebitda | Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, probability		99.00%
Discount rate		6.00%
Forecasted Revenues | Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, probability		72.00%
Discount rate		8.00%
Outperformance Revenue | Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, probability		29.00%
Discount rate		10.00%
Revenue Earnout | Avionics Interface Technologies, LLC
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, probability		36.00%
Discount rate		4.70%

Schedule of Carrying Amounts an

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014	Sep. 28, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	$ 294,217	$ 294,256	$ 211,704	$ 341,638
Marketable securities	782,941	1,004,576
Contingent consideration	14,447	895
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	294,217	294,256
Marketable securities	782,941	1,004,576
Derivative assets	109	220
Contingent consideration	34,595	3,350
Derivative liabilities	97	369
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	294,217	294,256
Marketable securities	782,941	1,004,576
Derivative assets	109	220
Contingent consideration	34,595	3,350
Derivative liabilities	$ 97	$ 369

Schedule of Available for Sale

Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 781,610	$ 1,000,625
Available-for-sale marketable securities, Unrealized Gain	3,252	4,818
Available-for-sale marketable securities, Unrealized (Loss)	(1,921)	(867)
Available-for-sale marketable securities, Fair Market Value	782,941	1,004,576
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	73,034	583,076
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	349,464	402,197
Available-for-sale marketable securities, Unrealized Gain	385	362
Available-for-sale marketable securities, Unrealized (Loss)	(196)	(405)
Available-for-sale marketable securities, Fair Market Value	349,653	402,154
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	19,260	317,771
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	213,149	258,452
Available-for-sale marketable securities, Unrealized Gain	342	135
Available-for-sale marketable securities, Unrealized (Loss)		(85)
Available-for-sale marketable securities, Fair Market Value	213,491	258,502
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses		104,642
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	115,130	139,374
Available-for-sale marketable securities, Unrealized Gain	1,305	2,414
Available-for-sale marketable securities, Unrealized (Loss)	(1,628)	(321)
Available-for-sale marketable securities, Fair Market Value	114,807	141,467
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	48,369	96,998
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	45,498	140,616
Available-for-sale marketable securities, Unrealized Gain	12	26
Available-for-sale marketable securities, Unrealized (Loss)		(4)
Available-for-sale marketable securities, Fair Market Value	45,510	140,638
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses		41,747
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	45,652	49,048
Available-for-sale marketable securities, Unrealized Gain	25	11
Available-for-sale marketable securities, Unrealized (Loss)		(23)
Available-for-sale marketable securities, Fair Market Value	45,677	49,036
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	3,505	20,684
Equity And Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	12,291	10,492
Available-for-sale marketable securities, Unrealized Gain	1,183	1,870
Available-for-sale marketable securities, Unrealized (Loss)	(97)	(29)
Available-for-sale marketable securities, Fair Market Value	13,377	12,333
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	1,900	1,234
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	426	446
Available-for-sale marketable securities, Fair Market Value	$ 426	$ 446

Schedule of Reported Available

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 781,610	$ 1,000,625
Available-for-sale marketable securities, Unrealized Gain	3,252	4,818
Available-for-sale marketable securities, Unrealized (Loss)	(1,921)	(867)
Available-for-sale marketable securities, Fair Market Value	782,941	1,004,576
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	73,034	583,076
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	525,052	533,833
Available-for-sale marketable securities, Unrealized Gain	335	99
Available-for-sale marketable securities, Unrealized (Loss)	(6)	(145)
Available-for-sale marketable securities, Fair Market Value	525,381	533,787
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	27,172	240,234
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	256,558	466,792
Available-for-sale marketable securities, Unrealized Gain	2,917	4,719
Available-for-sale marketable securities, Unrealized (Loss)	(1,915)	(722)
Available-for-sale marketable securities, Fair Market Value	257,560	470,789
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 45,862	$ 342,842

Contractual Maturities of Inves

Contractual Maturities of Investments Held (Detail) $ in Thousands	Oct. 04, 2015USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 525,052
Due after 1 year through 5 years, cost	199,957
Due after 5 years through 10 years, cost	6,075
Due after 10 years, cost	38,235
Total, cost	769,319
Due within one year, fair value	525,381
Due after 1 year through 5 years, fair value	200,305
Due after 5 years through 10 years, fair value	6,191
Due after 10 years, fair value	37,687
Total, fair value	$ 769,564

Schedule of Effect of Derivativ

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures
Derivatives not designated as hedging instruments	$ 12		$ 12		$ (149)
Foreign exchange contracts derivatives not designated as hedging instruments, Gains (Losses) Recognized in Statement of Operations	677	$ 237	2,555	$ (1,632)
Other (income) expense, net
Fair Value, Option, Quantitative Disclosures
Foreign exchange contracts derivatives not designated as hedging instruments, Gains (Losses) Recognized in Statement of Operations	677	$ 237	2,555	$ (1,632)
Not Designated as Hedging Instrument | Foreign Currency Forward Contracts | Prepayments
Fair Value, Option, Quantitative Disclosures
Derivatives assets not designated as hedging instruments	109		109		220
Not Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other Current Liabilities
Fair Value, Option, Quantitative Disclosures
Derivatives liability not designated as hedging instruments	$ (97)		$ (97)		$ (369)

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Apr. 27, 2015	Mar. 13, 2014	Apr. 01, 2009	Mar. 31, 2009	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014
Debt Instrument
Term of loan, years	5 years
Pledge percentage of capital stock	65.00%
Payments of long-term debt						$ 190,975,000
Common stock shares were issued for warrants exercised							21,200,000
Strike price per share of warrant							$ 7.6348
Maximum
Debt Instrument
Aggregate principal amount	$ 150,000,000
Commitment fee percentage of unused portion of credit facility	0.35%
Minimum
Debt Instrument
Commitment fee percentage of unused portion of credit facility	0.125%
Base Rate | Maximum
Debt Instrument
Debt instrument, basis spread on variable rate	1.00%
Base Rate | Minimum
Debt Instrument
Debt instrument, basis spread on variable rate	0.00%
London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument
Debt instrument, basis spread on variable rate	2.00%
London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument
Debt instrument, basis spread on variable rate	1.00%
Revolving Credit Facility
Debt Instrument
Credit facility, borrowing capacity	$ 350,000,000
Financing cost					$ 2,300,000
Financing cost, amortization term					5 years
4.50% Convertible Senior Notes Due March 15, 2014
Debt Instrument
Aggregate principal amount			$ 190,000,000	$ 175,000,000
Debt instrument, interest rate, stated percentage				4.50%
Additional aggregate principal amount			$ 15,000,000	$ 1,000
Senior notes maturity date			Mar. 15, 2014	Mar. 15, 2014
Conversion rate in number of shares				182.65			131.95
Number of shares excluded for conversion rate calculation							50.7
Trading days used to determine average price per share							25 days
Average trading price of common shares							$ 19.74
Payments of long-term debt					$ 190,000,000
Stock issued in conversion of notes					25,100,000
Stock received and retired		25,100,000

Interest Expense on Convertible

Interest Expense on Convertible Senior Notes (Detail) $ in Thousands	9 Months Ended
	Sep. 28, 2014USD ($)
Debt Instrument
Contractual interest expense on the coupon	$ 1,757
Amortization of the discount component and debt issuance fees recognized as interest expense	4,493
Total interest expense on the convertible debt	$ 6,250

Schedule of Prepayments (Detail

Schedule of Prepayments (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Prepaid And Other Current Assets [Line Items]
Contract manufacturer prepayments	$ 55,624	$ 65,972
Prepaid maintenance and other services	6,642	7,343
Prepaid taxes	6,585	11,462
Other prepayments	11,928	11,042
Total prepayments	$ 80,779	$ 95,819

Deferred Revenue and Customer59

Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Jul. 05, 2015	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Dec. 31, 2013
Deferred Revenue Arrangement
Extended warranty	$ 47,489	$ 43,299	$ 43,300	$ 43,497	$ 40,052	$ 34,909
Product maintenance and training	37,976		30,500
Customer advances	6,133		8,875
Undelivered elements and other	12,210		8,857
Total deferred revenue and customer advances	$ 103,808		$ 91,532

Warranty Accrual Included in Ot

Warranty Accrual Included in Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 8,228	$ 9,073	$ 8,942	$ 6,660
Acquisition			372
Accruals for warranties issued during the period	3,261	4,419	9,548	12,675
Adjustments related to pre-existing warranties	(1,211)	(559)	(3,039)	(1,000)
Settlements made during the period	(2,370)	(2,982)	(7,915)	(8,384)
Balance at end of period	$ 7,908	$ 9,951	$ 7,908	$ 9,951

Extended Product Warranty Inclu

Extended Product Warranty Included in Short and Long-Term Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 43,299	$ 40,052	$ 43,300	$ 34,909
Acquisition			699
Deferral of new extended warranty revenue	10,442	9,896	22,818	24,218
Recognition of extended warranty deferred revenue	(6,252)	(6,451)	(19,328)	(15,630)
Balance at end of period	$ 47,489	$ 43,497	$ 47,489	$ 43,497

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Mar. 30, 2014USD ($)	Oct. 04, 2015Age$ / sharesshares	Sep. 28, 2014$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award
Number of service-based stock options granted to executive officers | shares		0.1	0.1
Weighted average grant date fair value of stock options granted to executive officers		$ 4.43	$ 5.49
Stock options term		7 years
Stock based compensation expense | $	$ 6.6
TSR Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Total shareholder return performance measurement period		3 years
Minimum age of retirement to be eligible for PRSUs | Age		60
Minimum years of service for retirement to be eligible for PRSUs		10 years
Restricted stock unit awards granted | shares		0.2	0.1
Weighted average grant date fair value of restricted stock units granted		$ 18.21	$ 22.06
Estimated annual dividend amount per share		0.24
Stock price		$ 18.10	$ 19.16
TSR Performance-Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved		200.00%
TSR Performance-Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved		0.00%
Service-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted | shares		1.5	1.7
Weighted average grant date fair value of restricted stock units granted		$ 17.27	$ 19.09
Restricted Stock Units | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal installments		4 years
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Estimated annual dividend amount per share		$ 0.24
Stock price		$ 18.10	$ 19.16
Period of stock granted to employees and executive officers vest in equal installments		4 years

Schedule of Estimated Fair Valu

Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions (Detail) - TSR Performance-Based Restricted Stock Units	9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	0.77%	0.75%
Teradyne volatility-historical	28.20%	36.10%
Philadelphia Semiconductor Index volatility-historical	19.70%	24.60%
Dividend yield	1.33%	1.25%

Schedule of Estimated Fair Va64

Schedule of Estimated Fair Value of Stock Options Grant Using Black Scholes Option Pricing Model (Detail) - Stock Options	9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Expected life (years)	4 years	4 years
Risk-free interest rate	1.10%	1.20%
Volatility-historical	33.40%	38.80%
Dividend yield	1.33%	1.25%

Changes in Accumulated Other Co

Changes in Accumulated Other Comprehensive Income (Loss) Balances (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 4,689	$ 4,000
Other comprehensive income (loss) before reclassifications, net of tax			(3,593)	2,166
Amounts reclassified from accumulated other comprehensive income, net of tax	$ (321)	$ (712)	(1,029)	(1,307)
Other comprehensive income (loss)	3,229	(850)	(4,622)	859
Ending balance	67	4,859	67	4,859
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			2,365	1,381
Other comprehensive income (loss) before reclassifications, net of tax			(593)	2,166
Amounts reclassified from accumulated other comprehensive income, net of tax			(808)	(1,086)
Other comprehensive income (loss)			(1,401)	1,080
Ending balance	964	2,461	964	2,461
Retirement Plans Prior Service Benefit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			2,324	2,619
Amounts reclassified from accumulated other comprehensive income, net of tax			(221)	(221)
Other comprehensive income (loss)			(221)	(221)
Ending balance	2,103	$ 2,398	2,103	$ 2,398
Foreign currency translation reclassification adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, net of tax			(3,000)
Other comprehensive income (loss)			(3,000)
Ending balance	$ (3,000)		$ (3,000)

Changes in Accumulated Other 66

Changes in Accumulated Other Comprehensive Income (Loss) Balances (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income before reclassifications, tax			$ 0
Other comprehensive income before reclassifications, tax	$ 48	$ (139)	(896)	$ 1,103
Other comprehensive income before reclassifications, tax				0
Amounts reclassified from accumulated other comprehensive income, tax	(126)	(348)	(335)	(591)
Amounts reclassified from accumulated other comprehensive income, tax	(42)	(42)	(127)	(127)
Foreign currency translation adjustments, tax	0		0
Unrealized gains (losses) on marketable securities, tax	367	1,306	367	1,306	$ 1,598	$ 794
Retirement plans prior service benefit, tax	$ (580)	$ (411)	(580)	(411)	$ (453)	$ (284)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			(1,231)	512
Retirement Plans Prior Service Benefit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			(127)	$ (127)
Foreign currency translation reclassification adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			$ 0

Reclassification Out of Accumul

Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains, net of tax		$ 247	$ 638	$ 808	$ 1,086
Prior service benefit	[1]	74	74	221	221
Total reclassifications		321	712	1,029	1,307
Interest Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains, net of tax		$ 247	$ 638	$ 808	$ 1,086
[1]	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note O: "Retirement Plans."

Reclassification Out of Accum68

Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains, tax	$ 126	$ 348	$ 335	$ 591
Prior service benefit, tax	42	42	127	127
Total reclassifications, tax	$ 168	$ 390	$ 462	$ 718

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	9 Months Ended
	Oct. 04, 2015	Oct. 04, 2015	Jun. 11, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill beginning balance	$ 273,438
Foreign currency translation adjustment	(2,113)
Goodwill Ending balance	498,346
Goodwill		$ 1,005,966		$ 781,058
Accumulated impairment losses		(507,620)		(507,620)
Goodwill Ending balance	498,346	498,346		273,438
Universal Robots
Goodwill [Line Items]
Universal Robots acquisition	226,501
Universal Robots adjustment	520
Goodwill Ending balance			$ 227,021
Wireless Test
Goodwill [Line Items]
Goodwill beginning balance	262,922
Goodwill Ending balance	262,922
Goodwill		361,819		361,819
Accumulated impairment losses		(98,897)		(98,897)
Goodwill Ending balance	262,922	262,922		262,922
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	(2,113)
Goodwill Ending balance	224,908
Goodwill		224,908
Goodwill Ending balance	224,908	224,908
Industrial Automation | Universal Robots
Goodwill [Line Items]
Universal Robots acquisition	226,501
Universal Robots adjustment	520
System Test
Goodwill [Line Items]
Goodwill beginning balance	10,516
Goodwill Ending balance	10,516
Goodwill		158,699		158,699
Accumulated impairment losses		(148,183)		(148,183)
Goodwill Ending balance	$ 10,516	10,516		10,516
Semiconductor Test
Goodwill [Line Items]
Goodwill		260,540		260,540
Accumulated impairment losses		$ (260,540)		$ (260,540)

Schedule of Amortizable Intangi

Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Oct. 04, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 543,613	$ 523,052
Accumulated Amortization	283,319	332,452
Net Carrying Amount	$ 260,294	$ 190,600
Weighted Average Useful Life, years	6 years 8 months 12 days	6 years 9 months 18 days
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 381,071	$ 345,513
Accumulated Amortization	206,256	224,059
Net Carrying Amount	$ 174,815	$ 121,454
Weighted Average Useful Life, years	6 years	6 years 2 months 12 days
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 110,464	$ 146,635
Accumulated Amortization	59,395	93,998
Net Carrying Amount	$ 51,069	$ 52,637
Weighted Average Useful Life, years	7 years 10 months 24 days	7 years 8 months 12 days
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 51,588	$ 30,414
Accumulated Amortization	17,418	14,205
Net Carrying Amount	$ 34,170	$ 16,209
Weighted Average Useful Life, years	9 years 6 months	9 years
Non-compete agreement
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 320	$ 320
Accumulated Amortization	80	20
Net Carrying Amount	$ 240	$ 300
Weighted Average Useful Life, years	4 years	4 years
Customer order backlog
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 170	$ 170
Accumulated Amortization	$ 170	$ 170
Weighted Average Useful Life, years	3 months 18 days	3 months 18 days

Goodwill and Intangible Asset71

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Goodwill and Intangible Assets Disclosure [Line Items]
Fully amortized intangible assets wrote off			$ 98,200
Acquired intangible assets amortization	$ 20,053	$ 18,271	$ 49,119	$ 54,813

Schedule of Estimated Intangibl

Schedule of Estimated Intangible Asset Amortization Expense (Detail) $ in Thousands	Oct. 04, 2015USD ($)
Finite-Lived Intangible Assets
2015 (remainder)	$ 20,029
2,016	80,117
2,017	71,498
2,018	44,647
2,019	23,785
Thereafter	$ 20,218

Computation of Basic and Dilute

Computation of Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Net Income Loss Per Common Share
Net income for basic and diluted net income per share		$ 71,453	$ 82,949	$ 207,118	$ 185,083
Weighted average common shares-basic		210,032	207,381	213,688	198,367
Incremental shares from assumed conversion of convertible notes	[1]				6,684
Convertible note hedge warrant shares	[2]		8,885		16,744
Employee stock purchase plan		23	21	40	28
Dilutive potential common shares		1,704	10,952	1,660	25,428
Weighted average common shares-diluted		211,736	218,333	215,348	223,795
Net income per common share-basic		$ 0.34	$ 0.40	$ 0.97	$ 0.93
Net income per common share-diluted		$ 0.34	$ 0.38	$ 0.96	$ 0.83
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		1,103	1,167	994	975
Stock Options
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		578	879	626	997
[1]	Incremental shares from the assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
[2]	Convertible note hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period. Teradyne's call option on its common stock (convertible note hedge transaction) was excluded from the calculation of diluted shares because the effect was anti-dilutive. See Note F: "Debt" regarding the convertible note hedge transaction.

Computation of Basic and Dilu74

Computation of Basic and Diluted Net Income Per Common Share (Parenthetical) (Detail) shares in Millions	9 Months Ended
	Oct. 04, 2015$ / sharesshares
Convertible Notes
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 5.48
Shares that would be issued upon conversion	34.7
Convertible Notes Hedge Warrant
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 7.6650
Shares that would be issued upon conversion	34.7

Net Income Per Common Share - A

Net Income Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
Net Income Loss Per Common Share
Exercise of stock options	0.2	0.3	0.2	0.3

Restructuring and Other - Addit

Restructuring and Other - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015USD ($)Employee	Sep. 28, 2014USD ($)	Oct. 04, 2015USD ($)Employee	Sep. 28, 2014USD ($)Employee
Restructuring Cost and Reserve
Contingent consideration adjustment			$ (2,600)	$ (630)
Severance benefit and charges	$ 1,100		$ 1,400	$ 800
Reduction in employees headcount | Employee	18		22	30
Avionics Interface Technologies, LLC
Restructuring Cost and Reserve
Contingent consideration adjustment	$ (1,000)		$ (1,000)
Avionics Interface Technologies, LLC | Corporate And Eliminations
Restructuring Cost and Reserve
Contingent consideration adjustment			(1,000)
Universal Robots
Restructuring Cost and Reserve
Acquisition related costs	$ 100		1,100
ZTEC Instruments, Inc.
Restructuring Cost and Reserve
Contingent consideration adjustment		$ (600)	(1,600)	$ (600)
ZTEC Instruments, Inc. | Corporate And Eliminations
Restructuring Cost and Reserve
Contingent consideration adjustment			$ (1,600)

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) $ in Millions	9 Months Ended
	Oct. 04, 2015USD ($)
U.S. Supplemental Executive Defined Benefit Pension Plan
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 1.9
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 0.6

Schedule of Net Periodic Pensio

Schedule of Net Periodic Pension and Postretirement Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014
United States Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	$ 616	$ 555	$ 1,847	$ 1,663
Interest cost	3,285	3,219	9,856	9,656
Expected return on plan assets	(3,629)	(3,126)	(10,888)	(9,375)
Amortization of prior service cost (benefit)	34	34	101	101
Actuarial (gain) loss			(3)	362
Total net periodic	306	682	913	2,407
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	259	206	768	705
Interest cost	357	431	1,101	1,446
Expected return on plan assets	(185)	(209)	(595)	(685)
Total net periodic	431	428	1,274	1,466
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	12	15	36	44
Interest cost	59	84	177	252
Amortization of prior service cost (benefit)	(150)	(150)	(449)	(449)
Actuarial (gain) loss			(19)	(247)
Total net periodic	$ (79)	$ (51)	$ (255)	$ (400)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
	Oct. 04, 2015USD ($)
Purchase Commitment, Excluding Long-term Commitment
Aggregate purchase commitments	$ 219.6
Purchase commitments less than one year	$ 214.2
Maximum
Purchase Commitment, Excluding Long-term Commitment
Purchase commitments period	1 year

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2016	Dec. 31, 2014
Income Taxes [Line Items]
Effective tax rate	18.30%	17.60%	20.90%	15.90%
U.S. statutory federal tax rate			35.00%
Discrete tax benefit (expense) related to non-taxable currency gains	$ 3.3	$ (5.6)	$ 5	$ 2.6
Discrete tax benefit attributable to a United States tax court opinion regarding intercompany cost sharing arrangements	1.8		1.8
Decrease in uncertain tax position resulting from expiration of statutes of limitations	0.6		1.3
Other discrete tax benefits	0.9	0.7	1	2
Discrete tax benefit related to additions to the uncertain tax positions for transfer pricing net		7.2		7.2
Discrete tax benefits resulting from increases in credit carry forwards		$ 0.9		0.9
Discrete tax benefit related to disqualifying dispositions of incentive stock options and employee stock purchase plan shares			0.9	1.7
Uncertain tax positions	$ 33.3		33.3			$ 30.4
Net Increase in uncertain tax positions			2.9
Interest and penalties related to income tax			0.3			$ 0.6
Tax savings due to the tax holiday			$ 9.9	$ 12.3
Tax savings due to the tax holiday, per share			$ 0.05	$ 0.05
Tax holiday expiration date			Dec. 31, 2015
Scenario, Forecast
Income Taxes [Line Items]
Decrease in uncertain tax position resulting from expiration of statutes of limitations					$ 0.1

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Oct. 04, 2015Segment
Segment Reporting Information [Line Items]
Operating segments	4

Schedule of Segment Information

Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Oct. 04, 2015		Sep. 28, 2014		Oct. 04, 2015		Sep. 28, 2014		Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues		$ 465,994		$ 478,010		$ 1,321,133		$ 1,324,587
Income (loss) before income taxes	[1],[2]	87,408		100,670		261,981		220,189
Total assets		2,661,884	[3]	2,695,007	[3]	2,661,884	[3]	2,695,007	[3]	$ 2,538,520
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		325,516		380,083		996,748		1,063,254
Income (loss) before income taxes	[1],[2]	73,957		91,900		246,627		233,770
Total assets	[3]	591,445		748,499		591,445		748,499
Wireless Test
Segment Reporting Information [Line Items]
Revenues		55,359		54,838		152,285		144,747
Income (loss) before income taxes	[1],[2]	2,997		2,379		(603)		(8,477)
Total assets	[3]	447,461		614,911		447,461		614,911
System Test
Segment Reporting Information [Line Items]
Revenues		69,062		43,089		152,320		116,586
Income (loss) before income taxes	[1],[2]	13,751		5,779		10,423		5,512
Total assets	[3]	109,078		83,769		109,078		83,769
Corporate And Eliminations
Segment Reporting Information [Line Items]
Income (loss) before income taxes	[1],[2]	1,550		612		12,081		(10,616)
Total assets	[3]	1,153,832		$ 1,247,828		1,153,832		$ 1,247,828
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		16,057				19,780
Income (loss) before income taxes	[1],[2]	(4,847)				(6,547)
Total assets	[3]	$ 360,068				$ 360,068
[1]	Included in the income (loss) before income taxes for each of the segments are charges related to inventory and other.
[2]	Interest income, interest expense, and other (income) expense, net are included in Corporate and Eliminations.
[3]	Total business assets are directly attributable to each business. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.

Schedule of Segment Reporting I

Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Mar. 30, 2014	Oct. 04, 2015	Sep. 28, 2014
Segment Reporting Information [Line Items]
Restructuring and other		$ 261	$ (405)		$ (124)	$ 167
Contingent consideration adjustment					(2,600)	(630)
Gain from the sale of an equity investment					(5,406)
Stock based compensation expense				$ 6,600
ZTEC Instruments, Inc.
Segment Reporting Information [Line Items]
Contingent consideration adjustment			(600)		(1,600)	(600)
Universal Robots
Segment Reporting Information [Line Items]
Acquisition related costs		100			1,100
Avionics Interface Technologies, LLC
Segment Reporting Information [Line Items]
Contingent consideration adjustment		(1,000)			(1,000)
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		901	1,267		2,077	5,239
Restructuring and other						426
Total		901	1,267		2,077	5,665
System Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		460	763		8,225	1,944
Restructuring and other		923	225		923	371
Total		1,383	988		9,148	2,315
Industrial Automation
Segment Reporting Information [Line Items]
Cost of revenues-inventory step-up	[1]	972			1,567
Total		972			1,567
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		1,697	4,404		8,637	14,322
Restructuring and other		194			499
Total		1,891	4,404		9,136	14,322
Corporate And Eliminations
Segment Reporting Information [Line Items]
Total		(856)	(630)		(6,902)	5,968
Corporate And Eliminations | Other (income) expense, net
Segment Reporting Information [Line Items]
Gain from the sale of an equity investment					(5,406)
Corporate And Eliminations | Selling, General and Administrative Expenses
Segment Reporting Information [Line Items]
Stock based compensation expense	[2]					6,598
Corporate And Eliminations | ZTEC Instruments, Inc.
Segment Reporting Information [Line Items]
Contingent consideration adjustment					(1,600)
Corporate And Eliminations | ZTEC Instruments, Inc. | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment			$ (630)		(1,600)	$ (630)
Corporate And Eliminations | Universal Robots | Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs		144			1,104
Corporate And Eliminations | Avionics Interface Technologies, LLC
Segment Reporting Information [Line Items]
Contingent consideration adjustment					(1,000)
Corporate And Eliminations | Avionics Interface Technologies, LLC | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment		$ (1,000)			$ (1,000)
[1]	Included in the cost of revenues for the three and nine months ended October 4, 2015 is the cost for purchase accounting inventory step-up.
[2]	Expense related to the January 2014 retirement of Teradyne's former chief executive officer; see Note J: "Stock-Based Compensation."

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	Oct. 04, 2015	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Aug. 31, 2015	May. 31, 2015	Jan. 31, 2015	Aug. 31, 2014	Jan. 31, 2014
Stockholders Equity Note Disclosure [Line Items]
Stock repurchase program, intend to repurchase								$ 300,000,000
Repurchase of stock, shares	11.9
Repurchase of stock, value	$ 226,800,000
Common stock average price	$ 19.09
Dividends payable, amount per share						$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06
Dividend payment		$ 12,600,000	$ 12,800,000	$ 38,434,000	$ 24,428,000
Maximum
Stockholders Equity Note Disclosure [Line Items]
Stock repurchase program, authorized amount								$ 500,000,000