Teradyne (TER) 10-Q 9 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 05, 2019
Document and Entity Information [Abstract]
Amendment Flag	false
Document Type	10-Q
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000097210
Current Fiscal Year End Date	--12-31
Document Period End Date	Jun. 30, 2019
Entity Registrant Name	TERADYNE, INC
Entity Filer Category	Large Accelerated Filer
Trading Symbol	TER
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	001-06462
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	04-2272148
Entity Address, Address Line One	600 Riverpark Drive
Entity Address, City or Town	North Reading
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01864
City Area Code	978
Local Phone Number	370-2700
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		169,945,820

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019		Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 495,107		$ 926,752
Marketable securities	400,227		190,096
Accounts receivable, less allowance for doubtful accounts of $1,736 and $1,673 at June 30, 2019 and December 31, 2018, respectively	372,199		291,267
Inventories, net	164,461		153,541
Prepayments and other current assets	184,832		170,826
Total current assets	1,616,826		1,732,482
Property, plant and equipment, net	295,895		279,821
Operating lease right-of-use assets, net	56,315
Marketable securities	99,001		87,731
Deferred tax assets	67,886		70,848
Other assets	25,712		11,509
Retirement plans assets	16,449		16,883
Acquired intangible assets, net	109,494		125,482
Goodwill	383,936		381,850
Total assets	2,671,514	[1]	2,706,606
Current liabilities:
Accounts payable	103,449		100,688
Accrued employees' compensation and withholdings	121,940		148,566
Deferred revenue and customer advances	89,837		77,711
Other accrued liabilities	77,053		78,272
Current operating lease liabilities	18,041
Contingent consideration	11,753		34,865
Income taxes payable	44,927		36,185
Total current liabilities	467,000		476,287
Retirement plans liabilities	122,596		117,456
Long-term deferred revenue and customer advances	37,365		32,750
Deferred tax liabilities	17,800		20,662
Long-term other accrued liabilities	9,660		37,547
Long-term contingent consideration	15,094		35,678
Long-term operating lease liabilities	46,460
Long-term incomes taxes payable	88,884		83,891
Debt	387,243		379,981
Total liabilities	1,192,102		1,184,252
SHAREHOLDERS' EQUITY
Common stock, $0.125 par value, 1,000,000 shares authorized; 170,436 and 175,522 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	21,305		21,940
Additional paid-in capital	1,688,211		1,671,645
Accumulated other comprehensive loss	(7,591)		(13,040)
Accumulated deficit	(222,513)		(158,191)
Total shareholders' equity	1,479,412		1,522,354
Total liabilities and shareholders' equity	$ 2,671,514		$ 2,706,606
[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 BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable, less allowance for doubtful accounts	$ 1,736	$ 1,673
Common stock, par value	$ 0.125	$ 0.125
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	170,436,000	175,522,000
Common stock, shares outstanding	170,436,000	175,522,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Revenues:
Total revenues	$ 564,178	$ 526,929	$ 1,058,277	$ 1,014,396
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	240,260	219,595	446,724	437,230
Gross profit	323,918	307,334	611,553	577,166
Operating expenses:
Selling and administrative	108,811	99,410	210,824	189,916
Engineering and development	81,434	75,342	158,225	149,750
Acquired intangible assets amortization	10,083	9,793	20,717	17,491
Restructuring and other	(10,404)	2,389	(5,292)	2,076
Total operating expenses	189,924	186,934	384,474	359,233
Income from operations	133,994	120,400	227,079	217,933
Non-operating (income) expense:
Interest income	(5,430)	(5,427)	(13,482)	(11,407)
Interest expense	5,800	5,639	11,513	12,530
Other (income) expense, net	2,447	176	3,892	979
Income before income taxes	131,177	120,012	225,156	215,831
Income tax provision	33,780	18,975	18,621	27,821
Net income	$ 97,397	$ 101,037	$ 206,535	$ 188,010
Net income per common share:
Basic	$ 0.57	$ 0.53	$ 1.20	$ 0.97
Diluted	$ 0.55	$ 0.52	$ 1.16	$ 0.94
Weighted average common shares-basic	171,241	190,730	172,387	192,992
Weighted average common shares-diluted	178,590	194,909	177,781	199,197
Product [Member]
Revenues:
Total revenues	$ 457,511	$ 434,051	$ 850,953	$ 837,976
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	193,299	180,777	358,667	361,735
Service [Member]
Revenues:
Total revenues	106,667	92,878	207,324	176,420
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	$ 46,961	$ 38,818	$ 88,057	$ 75,495

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Net income	$ 97,397	$ 101,037	$ 206,535	$ 188,010
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax of $0	5,642	(29,323)	983	(18,781)
Available-for-sale marketable securities:
Unrealized gains (losses) on marketable securities arising during period, net of tax of $678, $(25), $1,256, $(744), respectively	2,537	198	4,637	(2,489)
Less: Reclassification adjustment for (gains) losses included in net income, net of tax of $(6), $(68), $(26), $11, respectively	(27)	(199)	(97)	1,469
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	2,510	(1)	4,540	(1,020)
Defined benefit pension and post-retirement plans:
Amortization of prior service benefit included in net periodic pension and post-retirement benefit, net of tax of $(11), $(18), $(21), $(35), respectively	(37)	(61)	(74)	(123)
Other comprehensive income (loss)	8,115	(29,385)	5,449	(19,924)
Comprehensive income	$ 105,512	$ 71,652	$ 211,984	$ 168,086

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Foreign currency translation adjustments, tax	$ 0
Unrealized gains (losses) on marketable securities arising during period, net of tax	678	$ (25)	$ 1,256	$ (744)
Reclassification adjustment for (gains) losses included in net income, net of tax	(6)	(68)	(26)	11
Amortization of prior service benefit included in net periodic pension and post-retirement benefit, net of tax	$ (11)	$ (18)	$ (21)	$ (35)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance at Jan. 01, 2018	$ 1,953,646	$ 24,444	$ 1,638,413	$ 18,776	$ 272,013
Balance, Shares at Jan. 01, 2018		195,548
Net issuance of common stock under stock-based plans	(8,086)	$ 157	(8,243)
Net issuance of common stock under stock-based plans (in shares)		1,253
Stock-based compensation expense	15,509		15,509
Repurchase of common stock	(367,191)	$ (1,106)			(366,085)
Repurchase of common stock (in shares)		(8,839)
Cash dividends	(34,703)				(34,703)
Net income	188,010				188,010
Other comprehensive Income (loss)	(19,924)			(19,924)
Reclassification of unrealized gains on equity securities				(3,125)	3,125
Reclassification of tax effects resulting from the Tax Reform Act				769	(769)
Balance at Jul. 01, 2018	1,739,940	$ 23,495	1,645,679	(3,504)	74,270
Balance, Shares at Jul. 01, 2018		187,962
Balance at Apr. 01, 2018	1,904,983	$ 24,226	1,638,756	25,881	216,120
Balance, Shares at Apr. 01, 2018		193,808
Net issuance of common stock under stock-based plans	(107)	$ 7	(114)
Net issuance of common stock under stock-based plans (in shares)		54
Stock-based compensation expense	7,037		7,037
Repurchase of common stock	(226,520)	$ (738)			(225,782)
Repurchase of common stock (in shares)		(5,900)
Cash dividends	(17,105)				(17,105)
Net income	101,037				101,037
Other comprehensive Income (loss)	(29,385)			(29,385)
Reclassification of tax effects resulting from the Tax Reform Act				260
Balance at Jul. 01, 2018	1,739,940	$ 23,495	1,645,679	(3,504)	74,270
Balance, Shares at Jul. 01, 2018		187,962
Cumulative effect of changes in accounting principle related to revenue recognition	12,679				12,679
Balance at Dec. 31, 2018	1,522,354	$ 21,940	1,671,645	(13,040)	(158,191)
Balance, Shares at Dec. 31, 2018		175,522
Net issuance of common stock under stock-based plans	643	$ 174	469
Net issuance of common stock under stock-based plans (in shares)		1,385
Stock-based compensation expense	16,097		16,097
Repurchase of common stock	(240,624)	$ (809)			(239,815)
Repurchase of common stock (in shares)		(6,471)
Cash dividends	(31,042)				(31,042)
Net income	206,535				206,535
Other comprehensive Income (loss)	5,449			5,449
Reclassification of tax effects resulting from the Tax Reform Act				171
Balance at Jun. 30, 2019	1,479,412	$ 21,305	1,688,211	(7,591)	(222,513)
Balance, Shares at Jun. 30, 2019		170,436
Balance at Mar. 31, 2019	1,470,228	$ 21,544	1,679,997	(15,706)	(215,607)
Balance, Shares at Mar. 31, 2019		172,353
Net issuance of common stock under stock-based plans	692	$ 13	679
Net issuance of common stock under stock-based plans (in shares)		99
Stock-based compensation expense	7,535		7,535
Repurchase of common stock	(89,154)	$ (252)			(88,902)
Repurchase of common stock (in shares)		(2,016)
Cash dividends	(15,401)				(15,401)
Net income	97,397				97,397
Other comprehensive Income (loss)	8,115			8,115
Reclassification of tax effects resulting from the Tax Reform Act				64
Balance at Jun. 30, 2019	$ 1,479,412	$ 21,305	$ 1,688,211	$ (7,591)	$ (222,513)
Balance, Shares at Jun. 30, 2019		170,436

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Common Stock, Dividends, Per Share, Cash Paid	$ 0.09	$ 0.09	$ 0.09	$ 0.09

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Cash flows from operating activities:
Net income	$ 206,535	$ 188,010
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	33,882	33,156
Amortization	24,976	20,177
Stock-based compensation	18,109	17,625
Deferred taxes	515	17,312
Provision for excess and obsolete inventory	5,799	6,175
Contingent consideration fair value adjustment	(8,701)	(8,468)
(Gains) losses on marketable securities	(3,741)	762
Retirement plan actuarial losses (gains)	448	(71)
Other	429	406
Changes in operating assets and liabilities, net of businesses acquired:
Accounts receivable	(79,478)	(179,403)
Inventories	(2,447)	(21,283)
Prepayments and other assets	(17,067)	1,641
Accounts payable and other liabilities	(14,424)	(8,155)
Deferred revenue and customer advances	15,826	10,518
Retirement plans contributions	(2,414)	(2,173)
Income taxes	(14,973)	(26,308)
Net cash provided by operating activities	163,274	49,921
Cash flows from investing activities:
Purchases of property, plant and equipment	(58,956)	(62,663)
Purchases of marketable securities	(484,181)	(647,071)
Proceeds from sales of marketable securities	42,454	829,053
Proceeds from maturities of marketable securities	233,193	469,862
Proceeds from life insurance	273
Purchase of investments and acquisition of businesses, net of cash acquired	(21,970)	(170,632)
Net cash (used for) provided by investing activities	(289,187)	418,549
Cash flows from financing activities:
Issuance of common stock under stock purchase and stock option plans	15,089	10,681
Repurchase of common stock	(247,222)	(360,795)
Dividend payments	(31,019)	(34,682)
Payments related to net settlement of employee stock compensation awards	(14,446)	(19,751)
Payments of contingent consideration	(27,615)	(13,571)
Net cash used for financing activities	(305,213)	(418,118)
Effects of exchange rate changes on cash and cash equivalents	(519)	189
(Decrease) increase in cash and cash equivalents	(431,645)	50,541
Cash and cash equivalents at beginning of period	926,752	429,843
Cash and cash equivalents at end of period	$ 495,107	$ 480,384

The Company

The Company	6 Months Ended
	Jun. 30, 2019
The Company	A. THE COMPANY Teradyne, Inc. (“Teradyne”) is a leading global supplier of automation equipment for test and industrial applications. Teradyne designs, develops, manufactures and sells automatic test systems used to test semiconductors, wireless products, data storage and complex electronics systems in the consumer electronics, wireless, automotive, industrial, computing, communications, and aerospace and defense industries. Teradyne’s industrial automation products include collaborative robotic arms, autonomous mobile robots, and advanced robotic control software used by global manufacturing and light industrial customers to improve quality, increase manufacturing and material handling efficiency and decrease manufacturing costs. Teradyne’s automatic test equipment and industrial automation products and services include: • semiconductor test (“Semiconductor Test”) systems; • industrial automation (“Industrial Automation”) products; • 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 • wireless test (“Wireless Test”) systems.

Accounting Policies

Accounting Policies	6 Months Ended
	Jun. 30, 2019
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 statement of such interim financial statements. Certain prior year amounts were reclassified to conform to the current year presentation. The December 31, 2018 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, 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. Investment in Other Company Teradyne holds an investment in a private company that develops and sells advanced wearable technology . Teradyne does not have the ability to exert significant influence over the company. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer on a quarterly basis. See Note D: “Acquisitions and Investment in Other Company.” Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” right-of-use 2018-11, “Leases (Topic 842): Targeted Improvements,” under the transition guidance which included the carry-forward of historical lease classification. Adoption of ASC resulted in recording ROU assets and lease liabilities of approximately $ million and $ million, respectively. Operating lease liabilities were calculated using the discount rate on January , . The adoption of ASC did not have a material impact on beginning retained earnings, the consolidated statement of operations, cash flows, or earnings per share. Under ASC 842, a contract is or contains a lease when Teradyne has the right to control the use of an identified asset. Teradyne determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The commencement date of the lease is the date that the lessor makes an underlying asset available for use by Teradyne. As of June 30, 2019, Teradyne does not have material leases that have not yet commenced. Teradyne determines if the lease is operating or finance at the lease commencement date based upon the terms of the lease and the nature of the asset. The lease term used to calculate the lease liability includes options to extend or terminate the lease when it is reasonably certain that the option will be exercised. For leases commencing after January 1, 2019, the lease liability is measured at the present value of future lease payments, discounted using the discount rate for the lease at the commencement date. As Teradyne is typically unable to determine the implicit rate, Teradyne uses an incremental borrowing rate based on the lease term and economic environment at commencement date. Teradyne initially measures payments based on an index by using the applicable rate at lease commencement. Variable payments that do not depend on an index are not included in the lease liability and are recognized as they are incurred. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs, prepaid lease payments, and reduced by any lease incentives. Teradyne’s contracts often include non-lease non-lease

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2019
Recently Issued Accounting Pronouncements	C. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS On January 26, 2017, the FASB issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment.” one-step

Acquisitions and Investment In

Acquisitions and Investment In Other Company	6 Months Ended
	Jun. 30, 2019
Acquisitions and Investment In Other Company	D. ACQUISITIONS Acquisitions Lemsys SA On January 30, 2019, Teradyne acquired all of the issued and outstanding shares of Lemsys SA (“Lemsys”) for a total purchase price of approximately $9.1 million. Lemsys strengthens Teradyne’s position in the electrification trends of vehicles, solar, wind, and industrial applications. The Lemsys acquisition was accounted for as a business combination and, accordingly, the results have been included in Teradyne’s Semiconductor Test segment from the date of acquisition. Teradyne’s final allocation of the purchase price was goodwill of $1.4 million, which is not deductible for tax purposes, acquired intangible assets of $4.6 million with an average estimated useful life of 5.2 years, and $3.1 million of net tangible assets. The acquisition was not material to Teradyne’s condensed consolidated financial statements. Mobile Industrial Robots On April 25, 2018, Teradyne acquired all of the issued and outstanding shares of Mobile Industrial Robots Aps (“MiR”), a Danish limited liability company located in Odense, Denmark. MiR is the leading maker of collaborative autonomous mobile robots for industrial applications. MiR is part of Teradyne’s Industrial Automation segment. The total purchase price of $197.8 million included $145.2 million of cash paid and $52.6 million of contingent consideration measured at fair value. The contingent consideration is payable in Euros upon the achievement of certain thresholds and targets for revenue and earnings before interest and taxes for periods from January 1, 2018 to December 31, 2018; January 1, 2018 to December 31, 2019; and January 1, 2018 to December 31, 2020. The contingent consideration related to revenue for the period from January 1, 2018 to December 31, 2018 in the amount of $30.8 million was paid in March 2019. The remaining maximum contingent consideration that could be paid is $84.1 million. The valuation of the contingent consideration is dependent on the following assumptions: forecasted revenues, revenue volatility, earnings before interest and taxes, and discount rate. These assumptions were estimated based on a review of the historical and projected results. The MiR 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. MiR’s products will help expand the Industrial Automation segment, which is a key component of Teradyne’s growth strategy. The allocation of the total purchase price to MiR’s 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 $136.0 million was allocated to goodwill, which is not deductible for tax purposes. MiR’s results have been included in Teradyne’s Industrial Automation segment from the date of acquisition. The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 135,976 Intangible assets 80,670 Tangible assets acquired and liabilities assumed: Current assets 6,039 Non-current 1,336 Accounts payable and current liabilities (7,336 ) Long-term deferred tax liabilities (18,007 ) Other long-term liabilities (900 ) Total purchase price $ 197,778 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 Life (in thousands) (in years) Developed technology $ 58,900 7.0 Trademarks and tradenames 13,240 11.0 Customer relationships 8,500 2.5 Backlog 30 0.2 Total intangible assets $ 80,670 7.2 The following unaudited pro forma information gives effect to the acquisition of MiR as if the acquisition occurred on January 1, 2018. 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 Six Months Ended July 1, 2018 July 1, 2018 (in thousands) Revenue $ 528,238 $ 1,021,194 Net income 101,780 186,787 Net income per common share: Basic $ 0.53 $ 0.97 Diluted $ 0.52 $ 0.94 Pro forma results for the three and six months ended July 1, 2018 were adjusted to exclude $2.3 million and $2.9 million of acquisition related costs . Energid Technologies Corporation On February 26, 2018, Teradyne acquired all of the issued and outstanding shares of Energid Technologies Corporation (“Energid”) for a total purchase price of approximately $27.6 million. Energid’s technology enables and simplifies the programming of complex robotic motions used in a wide variety of end markets, ranging from heavy industry to healthcare, utilizing both traditional robots and collaborative robots. The Energid acquisition was accounted for as a business combination and, accordingly, Energid’s results have been included in Teradyne’s Industrial Automation segment from the date of acquisition. As of the acquisition date, Teradyne’s purchase price allocation was goodwill of $14.4 million which is deductible for tax purposes, acquired intangible assets of $12.3 million with an average estimated useful life of 7.7 years, and $1.0 million of net tangible assets. The acquisition was not material to Teradyne’s condensed consolidated financial statements. Investment in Other Company On June 3, 2019, Teradyne invested $15.0 million in RealWear, Inc. (“RealWear”). RealWear, a private company, develops and sells advanced wearable technology including industrial, hands-free, head-mounted augmented reality devices that make the workplace safer and more productive. Teradyne’s investment in RealWear aligns with its strategy of bringing the power of advanced automation to companies of all sizes to improve the productivity of their employees and the quality of their products and services. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer on a quarterly basis. At June 30, 2019 the value of the investment was $15.0 million.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue	E. REVENUE For the three and six months ended June 30, 2019, revenues recognized in accordance with ASC 606: “ Revenue from Contracts with Customers” For the three and six months ended July 1, 2018, revenues recognized in accordance with ASC 606: “ Revenue from Contracts with Customers” For the three and six months ended July 1, 2018, Teradyne also recognized $ $7.9 million, respectively, of revenues from leases of Teradyne systems, which are accounted for outside of ASC 606. Disaggregation of Revenue The following table provides information about disaggregated revenue by primary geographical market, major product line and timing of revenue recognition. For the Three Months Ended June 30, 2019 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated System Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 7,426 $ 8,059 $ 17,225 $ 3,703 $ 1,341 $ 16,938 $ 2,783 $ — $ 5,250 $ (89 ) $ 62,636 Over time 8,175 724 6,850 — 792 255 — 787 676 — 18,259 Europe, Middle East and Africa Point in time 9,819 2,016 211 — 2,974 26,545 5,041 — 620 — 47,226 Over time 5,212 284 505 — 1,615 399 — 477 48 — 8,540 Asia Pacific Point in time 247,885 43,909 163 27,672 6,848 18,532 2,681 — 33,366 — 381,056 Over time 36,566 3,293 329 2,310 775 279 — 9 1,242 — 44,803 Lease Revenue 1,530 — — — 94 — — — 34 — 1,658 Total $ 316,613 $ 58,285 $ 25,283 $ 33,685 $ 14,439 $ 62,948 $ 10,505 $ 1,273 $ 41,236 $ (89 ) $ 564,178 For the Three Months Ended July 1, 2018 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 12,111 $ 2,827 $ 15,256 $ 5 $ 1,429 $ 16,053 $ 1,199 $ — $ 4,716 $ (110 ) $ 53,486 Over time 8,934 710 6,237 — 795 327 — — 122 — 17,125 Europe, Middle East and Africa Point in time 10,227 847 447 — 4,849 26,616 2,000 — 26 — 45,012 Over time 5,689 254 539 — 1,713 526 — — 257 — 8,978 Asia Pacific Point in time 218,352 59,633 385 31,824 3,741 13,895 1,310 — 27,663 — 356,803 Over time 34,951 2,285 258 1,428 744 131 — — 2,103 — 41,900 Lease Revenue 3,268 — — — 32 — — — 325 — 3,625 Total $ 293,532 $ 66,556 $ 23,122 $ 33,257 $ 13,303 $ 57,548 $ 4,509 $ — $ 35,212 $ (110 ) $ 526,929 For the Six Months Ended June 30, 2019 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 15,403 $ 16,110 $ 32,007 $ 5,295 $ 4,595 $ 32,235 $ 6,322 $ — $ 7,340 $ (240 ) $ 119,067 Over time 16,365 1,436 13,300 — 1,521 501 — 1,047 827 — 34,997 Europe, Middle East and Africa Point in time 20,851 2,168 250 — 8,038 52,448 8,883 — 1,356 — 93,994 Over time 10,493 563 974 — 3,169 815 — 766 93 — 16,873 Asia Pacific Point in time 467,698 79,415 426 44,279 10,483 32,709 4,408 — 57,995 — 697,413 Over time 75,479 6,573 1,093 4,364 1,696 507 — 221 2,601 — 92,534 Lease Revenue 3,197 — — — 137 — — — 65 — 3,399 Total $ 609,486 $ 106,265 $ 48,050 $ 53,938 $ 29,639 $ 121,249 $ 19,613 $ 2,034 $ 70,277 $ (240 ) $ 1,058,277 For the Six Months Ended July 1, 2018 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 21,711 $ 5,691 $ 26,853 $ 284 $ 3,189 $ 30,190 $ 1,199 $ — $ 9,695 $ (332 ) $ 98,480 Over time 17,517 1,406 12,425 — 1,552 652 — — 233 — 33,785 Europe, Middle East and Africa Point in time 22,352 986 1,943 — 8,886 49,190 2,000 — 1,066 — 86,423 Over time 10,888 523 1,090 — 3,272 668 — — 484 — 16,925 Asia Pacific Point in time 446,543 125,904 487 41,946 5,603 25,478 1,310 — 41,329 — 688,600 Over time 68,173 4,607 466 2,961 1,479 204 — — 4,399 — 82,289 Lease Revenue 7,115 — — — 266 — — — 513 — 7,894 Total $ 594,299 $ 139,117 $ 43,264 $ 45,191 $ 24,247 $ 106,382 $ 4,509 $ — $ 57,719 $ (332 ) $ 1,014,396 Contract Balances During the three and six months ended June 30, 2019, Teradyne recognized $13.3 million and $33.4 million, respectively, that was previously included within the deferred revenue and customer advances balances. During the three and six months ended July 1, 2018, Teradyne recognized $ million and $ million, respectively, % of the remaining performance obligation in the next months, % in 1-3 years, and the remainder thereafter. Accounts Receivable Teradyne sells certain trade accounts receivables on a non-recourse

Inventories

Inventories	6 Months Ended
	Jun. 30, 2019
Inventories	F. INVENTORIES Inventories, net consisted of the following at June 30, 2019 and December 31, 2018: June 30, December 31, (in thousands) Raw material $ 96,824 $ 89,365 Work-in-process 31,676 31,014 Finished goods 35,961 33,162 $ 164,461 $ 153,541 Inventory reserves at June 30, 2019 and December 31, 2018 were $102.6 million and $100.8 million, respectively.

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 30, 2019
Financial Instruments	G. FINANCIAL INSTRUMENTS 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’s available-for-sale During the three and six months ended June 30, 2019 and July 1, 2018, there were no transfers in or out of Level 1, Level 2, or Level 3 financial instruments. Realized gains recorded in the three and six months ended June 30, 2019 were $0.1 million and $0.2 million, respectively. Realized losses recorded in the six months ended June 30, 2019 were $0.1 million. Realized gains recorded in the three and six months ended July 1, 2018 were $0.1 million and $0.4 million, respectively. Realized losses recorded in the six months ended July 1, 2018 were $1.5 million. Realized gains are included in interest income and realized losses are included in interest expense. Unrealized gains on equity securities recorded in the three and six months ended June 30, 2019 were $0.9 million and $3.7 million, respectively. Unrealized gains on equity securities recorded in the three and six months ended July 1, 2018 were $0.4 million. Unrealized gains on equity securities are included in interest income and unrealized losses are included in interest expense. Unrealized gains and losses on available-for-sale The cost of securities sold is based on the specific identification method. 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 June 30, 2019 and December 31, 2018. June 30, 2019 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 235,370 $ — $ — $ 235,370 Cash equivalents 223,150 36,587 — 259,737 Available-for-sale U.S. Treasury securities — 190,322 — 190,322 Commercial paper — 154,910 — 154,910 Corporate debt securities — 94,431 — 94,431 Certificates of deposit and time deposits — 19,723 — 19,723 U.S. government agency securities — 9,838 — 9,838 Debt mutual funds 3,299 — — 3,299 Non-U.S. — 388 — 388 Equity securities: Mutual funds 26,317 — — 26,317 $ 488,136 $ 506,199 $ — $ 994,335 Derivative assets — 34 — 34 Total $ 488,136 $ 506,233 $ — $ 994,369 Liabilities Contingent consideration $ — $ — $ 26,847 $ 26,847 Derivative liabilities — 324 — 324 Total $ — $ 324 $ 26,847 $ 27,171 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 458,520 $ 36,587 $ — $ 495,107 Marketable securities — 400,227 — 400,227 Long-term marketable securities 29,616 69,385 — 99,001 Prepayments — 34 — 34 Total $ 488,136 $ 506,233 $ — $ 994,369 Liabilities . Other current liabilities $ — $ 324 $ — $ 324 Contingent consideration — — 11,753 11,753 Long-term contingent consideration — — 15,094 15,094 Total $ — $ 324 $ 26,847 $ 27,171 December 31, 2018 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 312,512 $ — $ — $ 312,512 Cash equivalents 253,525 360,715 — 614,240 Available-for-sale U.S. Treasury securities — 109,721 — 109,721 Commercial paper — 86,117 — 86,117 Corporate debt securities — 40,020 — 40,020 U.S. government agency securities — 9,611 — 9,611 Certificates of deposit and time deposits — 7,604 — 7,604 Debt mutual funds 3,187 — — 3,187 Non-U.S. — 376 — 376 Equity securities: Mutual funds 21,191 — — 21,191 $ 590,415 $ 614,164 $ — $ 1,204,579 Derivative assets — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Contingent consideration $ — $ — $ 70,543 $ 70,543 Derivative liabilities — 514 — 514 Total $ — $ 514 $ 70,543 $ 71,057 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 566,037 $ 360,715 $ — $ 926,752 Marketable securities — 190,096 — 190,096 Long-term marketable securities 24,378 63,353 — 87,731 Prepayments — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Other accrued liabilities $ — $ 514 $ — $ 514 Contingent consideration — — 34,865 34,865 Long-term contingent consideration — — 35,678 35,678 Total $ — $ 514 $ 70,543 $ 71,057 Changes in the fair value of Level 3 contingent consideration for the three and six months ended June 30, 2019 and July 1, 2018 were as follows: For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, (in thousands) Balance at beginning of period $ 38,313 $ 15,581 $ 70,543 $ 45,102 Fair value adjustment (a) (11,672 ) (3,500 ) (8,701 ) (8,468 ) Foreign currency impact 206 (2,566 ) (405 ) (2,566 ) Payments (b) — — (34,590 ) (24,553 ) Acquisition of MiR — 51,399 — 51,399 Balance at end of period $ 26,847 $ 60,914 $ 26,847 $ 60,914 (a) In the three and six months ended June 30, 2019, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was decreased by $11.7 million and $8.7 million, respectively, primarily due to a decrease in the forecasted revenue. In the three and six months ended July 1, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of Universal Robots A/S (“Universal Robots”) was decreased by $ 3.5 (b) In the six months ended June 30, 2019, Teradyne paid $30.8 million and $3.8 million of contingent consideration for the earn-outs in connection with the acquisition of MiR and Universal Robots, respectively. In the six months ended July 1, 2018, Teradyne paid $24.6 million of contingent consideration for the earn-out in connection with the acquisition of Universal Robots. The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instruments: Liability June 30, 2019 Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent consideration (MiR) $ 26,847 Monte Carlo Simulation Revenue volatility 19.0 Discount rate 0.2% As of June 30, 2019, the significant unobservable inputs used in the Monte Carlo simulation to fair value the MiR contingent consideration include forecasted revenues, revenue volatility, earnings before interest and taxes, and discount rate. Increases or decreases in the inputs would result in a higher or lower fair value measurement. As of June 30, 2019, the maximum amount of contingent consideration that could be paid in connection with the acquisition of MiR is $84.1 million. The remaining earn-out The carrying amounts and fair values of Teradyne’s financial instruments at June 30, 2019 and December 31, 2018 were as follows: June 30, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 495,107 $ 495,107 $ 926,752 $ 926,752 Marketable securities 499,228 499,228 277,827 277,827 Derivative assets 34 34 79 79 Liabilities Contingent consideration 26,847 26,847 70,543 70,543 Derivative liabilities 324 324 514 514 Convertible debt (1) 387,243 747,213 379,981 547,113 (1) The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note, which includes the equity conversion features. 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 table summarizes the composition of available-for-sale June 30, 2019 Available-for-Sale Fair Market Cost Unrealized Gain Unrealized (Loss) Fair Value Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 189,927 $ 668 $ (273 ) $ 190,322 $ 18,195 Commercial paper 154,903 9 (2 ) 154,910 10,322 Corporate debt securities 91,553 3,035 (157 ) 94,431 4,581 Certificates of deposit and time deposits 19,717 6 — 19,723 2,232 U.S. government agency securities 9,829 15 (6 ) 9,838 2,947 Debt mutual funds 3,187 112 — 3,299 — Non-U.S. 388 — — 388 — $ 469,504 $ 3,845 $ (438 ) $ 472,911 $ 38,277 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 399,852 $ 391 $ (16 ) $ 400,227 $ 21,708 Long-term marketable securities 69,652 3,454 (422 ) 72,684 16,569 $ 469,504 $ 3,845 $ (438 ) $ 472,911 $ 38,277 The following table summarizes the composition of available-for-sale December 31, 2018 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 110,969 $ 112 $ (1,360 ) $ 109,721 $ 75,040 Commercial paper 86,130 13 (26 ) 86,117 85,094 Corporate debt securities 41,133 432 (1,545 ) 40,020 24,767 U.S. government agency securities 9,646 1 (36 ) 9,611 7,077 Certificates of deposit and time deposits 7,604 — — 7,604 — Debt mutual funds 3,153 34 — 3,187 — Non-U.S. 376 — — 376 — $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 190,100 $ 88 $ (92 ) $ 190,096 $ 140,262 Long-term marketable securities 68,911 504 (2,875 ) 66,540 51,716 $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 As of June 30, 2019, the fair market value of investments in available-for-sale As of December 31, 2018, the fair market value of investments with unrealized losses totaled $192.0 million. Of this value, $28.5 million had unrealized losses of $1.6 million greater than one year and $163.5 million had unrealized losses of $1.4 million for 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 June 30, 2019 and December 31, 2018 were temporary. The contractual maturities of investments in available-for-sale June 30, 2019 Cost Fair Market Value (in thousands) Due within one year $ 399,852 $ 400,227 Due after 1 year through 5 years 12,304 12,411 Due after 5 years through 10 years 14,101 14,156 Due after 10 years 40,060 42,818 Total $ 466,317 $ 469,612 Contractual maturities of investments in available-for-sale 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 at June 30, 2019 and December 31, 2018 was $143.3 million and $163.1 million, respectively. 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 as of June 30, 2019 and December 31, 2018: Balance Sheet Location June 30, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts – derivative assets Prepayments $ 34 $ 79 Foreign exchange contracts – Other current liabilities (324 ) (514 ) Total derivatives $ (290 ) $ (435 ) The following table summarizes the effect of derivative instruments recognized in the statement of operations for the three and six months ended June 30, 2019 and July 1, 2018. Location of Losses (Gains) Recognized in Statement of Operations For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 239 $ 1,826 $ 4,173 $ 3,401 (1) The table does not reflect the corresponding gains and losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies. (2) For the three months ended June 30, 2019, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.3 million. For the six months ended June 30, 2019, net gains from the remeasurement of monetary assets and liabilities denominated in (3) For the three and six months ended July 1, 2018, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.9 million and $2.5 million, respectively. See Note I: “Debt” regarding derivatives related to the convertible senior notes.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Lease	H. LEASES On January 1, 2019, Teradyne adopted ASC 842 using the modified retrospective approach. Under this method of adoption, the comparative information in the consolidated financial statements has not been revised and continues to be reported under the previously applicable lease accounting guidance (ASC 840). Adoption of ASC 842 resulted in recording ROU assets and lease liabilities of approximately $50.1 million and $54.3 million, respectively. The adoption of ASC 842 did not have a material impact on beginning retained earnings, the consolidated statement of operations, cash flows, or earnings per share. Teradyne has facility and auto leases, which are accounted for as operating leases. Teradyne’s facility leases are primarily used for administrative functions, research and development, manufacturing, and storage and distribution. Remaining lease terms range from less than one year to ten years. Total lease expense for the three months ended June 30, 2019 was $8.9 million and included $2.6 million of variable lease costs and $0.8 million of costs related to short-term leases which are not recorded on the consolidated balance sheets. Total lease expense for the six months ended June 30, 2019 was $17.1 million and included $5.0 million of variable lease costs and $1.5 million of costs related to short-term leases which are not recorded on the consolidated balance sheets. At June 30, 2019, the weighted average remaining lease term and weighted average discount rate for operating leases was 4.7 years and 5.2%, respectively. Supplemental cash flow information related to leases was as follows: For the Three Months For the Six Months June 30, 2019 June 30, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows: $ 4,993 $ 10,052 Right-of-use 9,675 15,412 Maturities of lease liabilities as of June 30, 2019 were as follows: Operating Lease (in thousands) 2019 $ 10,725 2020 19,177 2021 16,510 2022 12,226 2023 5,849 Thereafter 12,583 Total lease payments 77,070 Less imputed interest (12,569 ) Total lease liabilities $ 64,501 As of December 31, 2018, future non-cancelable Operating Lease (in thousands) 2019 $ 19,570 2020 18,293 2021 13,578 2022 9,693 2023 5,449 Thereafter 9,472 Total lease payments $ 76,055

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt	I. DEBT Convertible Senior Notes On December , , Teradyne completed a private offering of $ million aggregate principal amount of % convertible senior unsecured notes (the “Notes”) due December 15, 2023 and received net proceeds, after issuance costs, of approximately $ million, $ million of which was used to pay the net cost of the convertible note hedge transactions and $ million of which was used to repurchase million shares of Teradyne’s common stock under its existing stock repurchase program from purchasers of the Notes in privately negotiated transactions effected through one of the initial purchasers or its affiliates conducted concurrently with the pricing of the Note offering. The Notes will mature on December , , unless earlier repurchased or converted. The Notes bear interest from December , at a rate of % per year , beginning on June 15, 2017 . The Notes will be convertible at the option of the noteholders at any time prior to the close of business on the business day immediately preceding September 15, 2023 , only under the following circumstances: during any calendar quarter beginning after March , (and only during such calendar quarter), if the closing sale price of Teradyne’s common stock, for at least trading days (whether or not consecutive) during a period of consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than % of the conversion price on each applicable trading day; during the five business day period after any five consecutive trading day period (the “measurement period”) in which the trading price (as defined in the Indenture) per $ principal amount of Notes for each trading day of the measurement period was less than % of the product of the closing sale price of the Teradyne’s common stock and the conversion rate on each such trading day; and upon the occurrence of specified corporate events. On or after September , until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their Notes at any time, regardless of the foregoing circumstances. Teradyne may satisfy its conversion obligation by paying or delivering cash, shares of its common stock or a combination of cash and shares of its common stock, at Teradyne’s election. As of June , , the conversion price was approximately $ per share of Teradyne’s common stock. The conversion rate is subject to adjustment under certain circumstances. Concurrent with the offering of the Notes, Teradyne entered into convertible note hedge transactions (the “Note Hedge Transactions”) with the initial purchasers or their affiliates (the “Option Counterparties”). The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, the number of shares of the common stock that underlie the Notes, with a strike price equal to the conversion price of the Notes of $31.70. The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, approximately 14.5 million shares of Teradyne’s common stock. Separately and concurrent with the pricing of the Notes, Teradyne entered into warrant transactions with the Option Counterparties (the “Warrant Transactions”) in which it sold net-share-settled The Note Hedge Transactions are expected to reduce the potential dilution to Teradyne’s common stock upon any conversion of the Notes. However, the Warrant Transactions could separately have a dilutive effect to the extent that the market value per share of Teradyne’s common stock exceeds the applicable strike price of the warrant. The net cost of the Note Hedge Transactions, after being partially offset by the proceeds from the sale of the warrants, was approximately $ million. In connection with establishing their initial hedge of these convertible note hedge and warrant transactions, the Option Counterparties have entered into various derivative transactions with respect to Teradyne’s common stock and/or purchased shares of Teradyne’s common stock or other securities, including the Notes, concurrent with, or shortly after, the pricing of the Notes. In addition, the Option Counterparties may modify their hedge positions by entering into or unwinding various derivative transactions with respect to Teradyne’s common stock or by selling Teradyne’s common stock or other securities, including the Notes, in secondary market transactions (and may do so during any observation period related to the conversion of the Notes). These activities could adversely affect the value of Teradyne’s common stock and the Notes. Teradyne considered the guidance of ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” and concluded that the convertible note hedge is both indexed to Teradyne’s common stock and should be classified in stockholders’ equity in its statements of financial position. The convertible note hedge is considered indexed to Teradyne’s common stock as the terms of the Note Hedge Transactions do not contain an exercise contingency and the settlement amount equals the difference between the fair value of a fixed number of Teradyne’s shares and a fixed strike price. Because the only variable that can affect the settlement amount is Teradyne’s stock price, which is an input to the fair value of a fixed-for-fixed option contract, the convertible note hedge is considered indexed to Teradyne’s common stock. Teradyne assessed whether the convertible note hedge should be classified as equity under ASC 815-40. In the Note Hedge Transactions contract the settlement terms permit net cash settlement or net share settlement, at the option of Teradyne. Therefore, the criteria as set forth in ASC 815-40 were evaluated by Teradyne. In reviewing the criteria, Teradyne noted the following: the convertible note hedge does not require Teradyne to issue shares; there is no requirement to net cash settle the convertible note hedge for failure to make timely filings with the SEC; in the case of termination, the convertible note hedge is settled in the same consideration as the holders of the underlying stock; (4) the counterparty does not have rights that rank higher than those of a shareholder of the stock underlying the convertible note hedge; and (5) there is no requirement to post collateral. Based on its analysis of those criteria, Teradyne concluded that the convertible note hedge should be recorded in equity and no further adjustment should be made in future periods to adjust the value of the convertible note hedge. Teradyne analyzed the Warrant Transactions under ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” The provisions of ASC 470-20, “ Debt with Conversion and Other Options, ” are applicable to the Notes. ASC 470-20 requires Teradyne to separately account for the liability (debt) and equity (conversion feature) components of the Notes in a manner that reflects Teradyne’s nonconvertible debt borrowing rate at the date of issuance when interest cost is recognized in subsequent periods. Teradyne allocated $100.8 million of the $460.0 million principal amount of the Notes to the equity component, which represents a discount to the debt and will be amortized to interest expense using the effective interest method through December 2023. Accordingly, Teradyne’s effective annual interest rate on the Notes will be approximately 5.0%. The Notes are classified as long-term debt in the balance sheet based on their December 15, 2023 maturity date. Debt issuance costs of approximately $ million are being amortized to interest expense using the effective interest method over the term of the Notes. As of June 30, 2019, debt issuance costs were approximately $ million. The below tables represent the key components of Teradyne’s convertible senior notes: June 30, December 31, (in thousands) Debt Principal $ 460,000 $ 460,000 Unamortized discount 72,757 80,019 Net Carrying amount of convertible debt $ 387,243 $ 379,981 For the Three Months For the Six Months June 30, July 1, June 30, July 1, (in thousands) Contractual interest expense on the coupon $ 1,438 $ 1,438 $ 2,875 $ 2,875 Amortization of the discount component recognized as interest expense 3,653 3,477 7,262 6,911 Total interest expense on the convertible debt $ 5,091 $ 4,915 $ 10,137 $ 9,786 As of June 30, 2019, the remaining unamortized discount was $72.8 million, which will be amortized over 4.5 years using the effective interest rate method. The carrying amount of the equity component was $100.8 million. As of June 30, 2019, the if-converted Revolving Credit Facility On , Teradyne terminated its , which Teradyne entered into with Barclays Bank PLC, on April 27, 2015. The terminated provided for a five-year, senior secured revolving credit facility of up to $ million.

Prepayments

Prepayments	6 Months Ended
	Jun. 30, 2019
Prepayments	J. PREPAYMENTS Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: June 30, 2019 December 31, 2018 (in thousands) Contract manufacturer and supplier prepayments $ 139,232 $ 131,642 Prepaid taxes 10,810 9,646 Prepaid maintenance and other services 9,935 8,487 Other prepayments 16,086 12,744 Total prepayments $ 176,063 $ 162,519

Deferred Revenue and Customer A

Deferred Revenue and Customer Advances	6 Months Ended
	Jun. 30, 2019
Deferred Revenue and Customer Advances	K. 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: June 30, 2019 December 31, (in thousands) Maintenance and training $ 60,331 $ 58,362 Extended warranty 28,716 27,422 Customer advances, undelivered performance obligations and other 38,155 24,677 Total deferred revenue and customer advances $ 127,202 $ 110,461

Product Warranty

Product Warranty	6 Months Ended
	Jun. 30, 2019
Product Warranty	L. PRODUCT WARRANTY Teradyne generally provides a one-year warranty on its products, commencing upon installation, acceptance, delivery 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. For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Balance at beginning of period $ 7,752 $ 7,548 $ 7,909 $ 8,200 Acquisition — 41 14 41 Accruals for warranties issued during the period 2,295 3,348 5,360 6,411 Accruals related to pre-existing 694 (34 ) 2,024 (173 ) Settlements made during the period (2,608 ) (3,767 ) (7,174 ) (7,343 ) Balance at end of period $ 8,133 $ 7,136 $ 8,133 $ 7,136 When Teradyne receives revenue for extended warranties, beyond one year, it is deferred and recognized on a straight-line basis over the contract period. Related costs are expensed as incurred. The balance below is included in short and long-term deferred revenue and customer advances on the balance sheet. For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Balance at beginning of period $ 27,242 $ 24,590 $ 27,422 $ 24,438 Deferral of new extended warranty revenue 5,476 6,701 11,296 11,839 Recognition of extended warranty deferred revenue (4,002 ) (5,320 ) (10,002 ) (10,306 ) Balance at end of period $ 28,716 $ 25,971 $ 28,716 $ 25,971

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2019
Stock-Based Compensation	M. STOCK-BASED COMPENSATION Under Teradyne’s stock compensation plans, Teradyne grants stock options, restricted stock units and performance-based restricted stock units, and employees are eligible to purchase Teradyne’s common stock through its Employee Stock Purchase Plan (“ESPP”). Time-based restricted stock unit awards granted to employees vest in equal annual installments over . Restricted stock unit awards granted to non-employee directors vest after a period, with % of the award vesting on the earlier of (a) the first anniversary of the grant date or (b) the date of the following year’s Annual Meeting of Shareholders. Teradyne expenses the cost of the restricted stock unit awards subject to time-based vesting, which is determined to be the fair market value of the shares at the date of grant, ratably over the period during which the restrictions lapse. Performance-based restricted stock units (“PRSUs”) granted to Teradyne’s executive officers have a performance metric based on relative total shareholder return (“TSR”). Teradyne’s three-year TSR performance is measured against the New York Stock Exchange (“NYSE”) Composite Index. The final number of TSR PRSUs that vest will vary based upon the level of performance achieved from % to % of the target shares capped at four times the grant date value. The TSR PRSUs will vest upon the three-year anniversary of the grant date. 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 shorter of the three-year service period or the period from the grant to the date described in the retirement provisions below. Compensation expense for employees meeting the retirement provisions prior to the grant date will be recognized in full on the date of the grant. 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 below. During the six months ended June 30, 2019 and July 1, 2018, Teradyne granted PRSUs to its executive officers with a performance metric based on three-year cumulative non-GAAP Non-GAAP non-cash non-recurring will be recognized in full on the date of grant. Compensation expense is recognized based on the number of units that are earned based upon the three-year Teradyne PBIT as a percent of Teradyne’s revenue, provided the executive officer remains an employee at the end of the three-year period subject to the retirement and termination eligibility provisions noted below. If a PRSU 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 During the six months ended June 30, 2019 and July 1, 2018, Teradyne granted 0.1 million and 0.1 million TSR PRSUs, respectively, with a grant date fair value of $51.51 and $54.85, respectively. The fair value was estimated using the Monte Carlo simulation model with the following assumptions: For the Six Months Ended June 30, 2019 July 1, 2018 Risk-free interest rate 2.6 % 2.2 % Teradyne volatility-historical 31.9 % 26.8 % NYSE Composite Index volatility-historical 11.9 % 12.4 % Dividend yield 1.0 % 0.8 % Expected volatility was based on the historical volatility of Teradyne’s stock and the NYSE Composite Index for each of the 2019 and 2018 grants 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 each of the grants. Dividend yield was based upon an estimated annual dividend amount of $0.36 per share for 2019 grants and 2018 grants, divided by Teradyne’s stock price on the grant date of $37.95 $ for the 2018 grant. During the six months ended June 30, 2019 and July 1, 2018, Teradyne granted 0.1 million and 0.1 million, respectively, of PBIT PRSUs with a grant date fair value of $36.88 and $46.62, respectively. During the six months ended June 30 , 2019 , Teradyne granted 0.7 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $36.10 , 0.1 million of service-based restricted stock unit awards to non-employee directors at a weighted average grant date fair value of $ 48.03 and 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $ 10.61 . During the six months ended July 1, 2018, Teradyne granted 0.6 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $46.38 , 0.1 million of service-based restricted stock unit awards to non-employee directors at a weighted average grant date fair value of $35.81, and million of service-based stock options to executive officers at a weighted average grant date fair value of $ . Restricted stock unit awards granted to employees vest in equal annual installments over four years. Stock options to purchase Teradyne’s common stock at 100% of the fair market value on the grant date vest in equal annual installments over four years from the grant date and have a maximum term of seven years. The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Six Months Ended June 30, 2019 July 1, 2018 Expected life (years) 5.0 5.0 Risk-free interest rate 2.5 % 2.4 % Volatility-historical 30.1 % 26.4 % Dividend yield 1.0 % 0.8 % 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 $0.36 per share divided by Teradyne’s stock price on the grant date of $37.95 for 2019 grants and $47.70 for the 2018 grant.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss)	N. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Changes in accumulated other comprehensive income (loss), which are presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended June 30, 2019 Balance at December 31, 2018, net of tax of $0, $(521), $(1,081), respectively $ (12,523 ) $ (1,845 ) $ 1,328 $ (13,040 ) Other comprehensive income before reclassifications, net of tax of $0, $1,256, $0, respectively 983 4,637 — 5,620 Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(26), $(21), respectively — (97 ) (74 ) (171 ) Net current period other comprehensive income (loss), net of tax of $0, $1,230, $(21), respectively 983 4,540 (74 ) 5,449 Balance at June 30, 2019, net of tax of $0, $709, $(1,102), respectively $ (11,540 ) $ 2,695 $ 1,254 $ (7,591 ) Foreign Currency Translation Adjustments Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended July 1, 2018 Balance at December 31, 2017, net of tax of $0, $1,815, $(932), respectively $ 15,919 $ 1,362 $ 1,495 $ 18,776 Other comprehensive income (loss) before reclassifications, net of tax of $0, $(774), $0, respectively (18,781 ) (2,489 ) — (21,270 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $11, $(35), respectively — 1,469 (123 ) 1,346 Net current period other comprehensive income (loss), net of tax of $0, $(733), $(35), respectively (18,781 ) (1,020 ) (123 ) (19,924 ) Reclassification of income tax effects from the Tax Reform Act, net of tax of $0, $(691), $(78), respectively (a) — 691 78 769 Reclassification of unrealized gains on equity securities, net of tax of $0, $(902), $0, respectively (b) — (3,125 ) — (3,125 ) Balance as July 1, 2018, net of tax of $0, $(511), $(1,045), respectively $ (2,862 ) $ (2,092 ) $ 1,450 $ (3,504 ) (a) In the six months ended July 1, 2018, Teradyne early adopted the ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” (b) In the six months ended July 1, 2018, Teradyne adopted the ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” Reclassifications out of accumulated other comprehensive income (loss) to the statement of operations for the three and six months ended June 30, 2019 and July 1, 2018 were as follows: Details about Accumulated Other Comprehensive Income Components For the Three Months Ended For the Six Months Ended Affected Line Item in the Statements of Operations June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Available-for-sale Unrealized gains (losses), net of tax of $6, $68, $26, $(11), $ 27 $ 199 $ 97 $ (1,469 ) Interest income Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $11, $18, 37 61 74 123 (a) Total reclassifications, net of tax of $17, $86, $47, $24, respectively $ 64 $ 260 $ 171 $ (1,346 ) Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit. See Note R: “Retirement Plans.”

Goodwill and Acquired Intangibl

Goodwill and Acquired Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets	O. GOODWILL AND ACQUIRED INTANGIBLE ASSETS Goodwill Teradyne performs its annual goodwill impairment test as required under the provisions of ASC 350-10, “Intangibles—Goodwill and Other” on December 31 of each fiscal year unless interim indicators of impairment exist. Goodwill is considered impaired when the net book value of a reporting unit exceeds its estimated fair value. The changes in the carrying amount of goodwill by reportable segments for the six months ended June 30, 2019, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2018 Goodwill $ 363,358 $ 158,699 $ 361,819 $ 260,540 $ 1,144,416 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 363,358 10,516 7,976 — 381,850 Lemsys acquisition — — — 1,428 1,428 Foreign currency translation adjustment 626 — — 32 658 Balance at June 30, 2019 Goodwill 363,984 158,699 361,819 262,000 1,146,502 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 363,984 $ 10,516 $ 7,976 $ 1,460 $ 383,936 Intangible Assets Teradyne reviews long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable or that the useful lives of these assets are no longer appropriate. Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet: June 30, 2019 Gross Carrying Amount (1)(2) Accumulated Amortization (2) Foreign Adjustment Net Carrying Amount (in thousands) Developed technology $ 337,198 $ (265,951 ) $ (4,035 ) $ 67,212 Customer relationships 100,313 (87,496 ) (285 ) 12,532 Tradenames and trademarks 64,670 (34,131 ) (789 ) 29,750 Total intangible assets $ 502,181 $ (387,578 ) $ (5,109 ) $ 109,494 December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Net Carrying Amount (in thousands) Developed technology $ 336,308 $ (252,080 ) $ (4,079 ) $ 80,149 Customer relationships 97,153 (83,448 ) (340 ) 13,365 Tradenames and trademarks 64,420 (31,653 ) (799 ) 31,968 Non-compete 320 (320 ) — — Backlog 30 (30 ) — — Total intangible assets $ 498,231 $ (367,531 ) $ (5,218 ) $ 125,482 (1) Includes $4.6 million of intangible assets from Lemsys acquisition. (2) $0.7 million of amortizable intangible assets became fully amortized and have been eliminated from the gross carrying amount and accumulated amortization. Aggregate intangible asset amortization expense was $10.1 million and $20.7 million, respectively, for the three and six months ended June 30, 2019 and $9.8 million and $17.5 million, respectively, for the three and six months ended July 1, 2018. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2019 (remainder) 18,745 2020 25,037 2021 14,778 2022 13,885 2023 13,410 Thereafter 23,639

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2019
Net Income per Common Share	P. 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 Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 97,397 $ 101,037 $ 206,535 $ 188,010 Weighted average common shares-basic 171,241 190,730 172,387 192,992 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 4,364 2,643 3,275 3,520 Convertible note hedge warrant shares (2) 1,778 — 889 915 Restricted stock units 1,002 1,219 1,012 1,444 Stock options 183 274 202 298 Employee stock purchase plan 22 43 16 28 Dilutive potential common shares 7,349 4,179 5,394 6,205 Weighted average common shares-diluted 178,590 194,909 177,781 199,197 Net income per common share-basic $ 0.57 $ 0.53 $ 1.20 $ 0.97 Net income per common share-diluted $ 0.55 $ 0.52 $ 1.16 $ 0.94 (1) Incremental shares from 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 $ 31.70 (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 $39.78, multiplied by 14.5 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. The computation of diluted net income per common share for the three and six months ended June 30, 2019 excludes the effect of the potential vesting of 0.2 million and 0.4 million of stock options, respectively because the effect would have been anti-dilutive. The computation of diluted net income per common share for the three and six months ended July 1, 2018 excludes the effect of the potential vesting of 0.6 million and 0.5 million shares, respectively of restricted stock units because the effect would have been anti-dilutive.

Restructuring and Other

Restructuring and Other	6 Months Ended
	Jun. 30, 2019
Restructuring and Other	Q. RESTRUCTURING AND OTHER During the three months ended June 30, 2019, Teradyne recorded an $ million credit for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $ million recorded for severance charges primarily in Semiconductor Test and $ million of acquisition related compensation and expenses. During the three months ended July 1, 2018, Teradyne recorded a $2.5 million charge for acquisition related expenses, and $ million for employee severance charges, primarily in Semiconductor Test, partially offset by a $ million credit for the decrease in the fair value of the Universal Robots. During the six months ended June 30, 2019, Teradyne recorded an $ million credit for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $ million of acquisition related compensation and expenses and $ million recorded for severance charges primarily in Semiconductor Test. During the six months ended July 1, 2018, Teradyne recorded $6.3 million for severance charges, primarily in Semiconductor Test and Industrial Automation, $3.3 million for acquisition related expenses, partially offset by an $8.5 million credit for the decrease in the fair value of the Universal Robots contingent consideration liability.

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 30, 2019
Retirement Plans	R. 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. In the six months ended June 30, 2019, Teradyne contributed $1.3 million to the U.S. supplemental executive defined benefit pension plan and $0.4 million to certain qualified pension plans for non-U.S. For the three and six months ended June 30, 2019 and July 1, 2018, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended June 30, 2019 July 1, 2018 United States Foreign United States Foreign (in thousands) Service cost $ 399 $ 192 $ 545 $ 200 Interest cost 1,799 176 2,430 175 Expected return on plan assets (1,510 ) (7 ) (2,550 ) (5 ) Amortization of prior service cost — — 14 — Net actuarial loss (gain) 252 — (189 ) — Settlement loss — — 78 — Total net periodic pension cost $ 940 $ 361 $ 328 $ 370 For the Six Months Ended June 30, 2019 July 1, 2018 United States Foreign United States Foreign (in thousands) Service cost $ 804 $ 381 $ 1,116 $ 426 Interest cost 3,595 349 5,427 372 Expected return on plan assets (3,021 ) (14 ) (5,919 ) (10 ) Amortization of prior service cost — — 29 — Net actuarial loss (gain) 252 — (189 ) — Settlement loss — — 78 — Total net periodic pension cost $ 1,630 $ 716 $ 542 $ 788 Postretirement Benefit Plan In addition to receiving pension benefits, Teradyne employees in the United States who meet early retirement eligibility requirements as of their termination dates may participate in Teradyne’s Welfare Plan, which includes medical and dental benefits up to age . 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 six months ended June 30, 2019 and July 1, 2018, Teradyne’s net periodic postretirement benefit cost was comprised of the following: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Service cost $ 11 $ 10 $ 20 $ 19 Interest cost 88 48 173 98 Amortization of prior service credit (48 ) (93 ) (95 ) (187 ) Net actuarial loss 196 40 196 40 Special termination benefits — 1,192 — 2,818 Total net periodic postretirement benefit cost $ 247 $ 1,197 $ 294 $ 2,788

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies	S. COMMITMENTS AND CONTINGENCIES Purchase Commitments As of June 30, 2019, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments covered by the agreements aggregate to approximately $306.9 million, of which $300.7 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	6 Months Ended
	Jun. 30, 2019
Income Taxes	T. INCOME TAXES A reconciliation of the United States federal statutory corporate tax rate to Teradyne’s effective tax rate was as follows: For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, US statutory federal tax rate 21.0 % 21.0 % 21.0 % 21.0 % Discrete expense related to U.S. transition tax 11.2 % 0.0 % 6.5 % 0.0 % International provisions of the U.S. Tax Cuts and Jobs Act of 2017 0.8 % (1.4 %) 0.8 % (1.4 %) Discrete benefit related to equity compensation (0.5 %) (0.1 %) (2.0 %) (3.5 %) Foreign taxes (4.9 %) (3.4 %) (4.9 %) (3.4 %) Tax credits (2.5 %) (2.1 %) (2.5 %) (2.1 %) Discrete benefit related to release of reserves for uncertain tax positions (0.1 %) 0.0 % (12.9 %) 0.0 % Other, net 0.8 % 1.8 % 2.3 % 2.3 % Effective tax rate 25.8 % 15.8 % 8.3 % 12.9 % 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 June 30, 2019, 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 As of June 30, 2019 and December 31, 2018, Teradyne had $13.4 million and $43.4 million, respectively, of reserves for uncertain tax positions. The $30.0 million net decrease in reserves for uncertain tax positions is primarily composed of reductions in uncertain tax positions amounting to $22.4 million related to transfer pricing and $7.3 million associated with U.S. research and development tax credits. These reductions resulted from the conclusion of the U.S. Federal income tax audit for the year ended December 31, 2015. As of June 30, 2019, Teradyne does not anticipate a material change in the balance of unrecognized tax benefits during the next twelve months. On July 27, 2015, in Altera Corp. v. Commissioner (“Altera”), the U.S. Tax Court issued an opinion invalidating the regulations relating to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision was issued by the Tax Court in December 2015. The IRS appealed the decision in June 2016. On July 24, 2018, the Ninth Circuit Federal Court issued a decision that was subsequently withdrawn and a reconstituted panel has conferred on the appeal. On June 7, 2019, the Ninth Circuit Federal Court upheld the cost-sharing regulations. Due to the uncertainty surrounding the status of the current regulations, questions related to the scope of potential benefits or obligations, the outcome of the appeals process, and questions regarding jurisdiction, Teradyne has not established any income tax reserves as of June 30, 2019 related to Altera. Teradyne estimates that including stock-based compensation in Teradyne’s intercompany cost-sharing arrangement could result in a potential tax reserve of $5 million to $11 million. Teradyne will continue to monitor ongoing developments and potential impacts to our consolidated financial statements. Teradyne recognizes interest and penalties related to income tax matters in income tax expense. As of June 30, 2019 and December 31, 2018, $0.4 million and $0.3 million, respectively, of interest and penalties were accrued for uncertain tax positions. For the six months ended June 30, 2019 and July 1, 2018, expense of $0.1 million and $0.1 million, respectively, was recorded for interest and penalties related to income tax items. 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 six months ended June 30, 2019 was $7.0 million, or $0.04 per diluted share. The tax savings due to the tax holiday for the six months ended July 1, 2018 was $4.8 million, or $0.02 per diluted share. The tax holiday is scheduled to expire on December 31, 2020.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information	U. SEGMENT INFORMATION Teradyne has four reportable segments (Semiconductor Test, System Test, Industrial Automation and Wireless Test). Each of the Semiconductor Test, System Test, and Wireless Test segments is also an individual operating segment. The Industrial Automation reportable segment consists of operating segments with discrete financial information, which have been combined into one reportable segment as they share similar economic characteristics, types of products, production processes, distribution channels, and currency risks. The Semiconductor Test segment includes operations related to the design, manufacturing and marketing of semiconductor 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 robotic arms, autonomous mobile robots and advanced robotic control software. The Wireless Test segment includes operations related to the design, manufacturing and marketing of wireless test products and services. Teradyne evaluates performance based on several factors, of which the primary financial measure is business segment income (loss) 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, 2018, and Note B: “Accounting Policies” in this filing for any changes in the three and six months ended June 30, 2019. Segment information for the three and six months ended June 30, 2019 and July 1, 2018 is as follows: Semiconductor Test Industrial Automation System Test Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended June 30, 2019 Revenues $ 374,898 $ 74,726 $ 73,407 $ 41,236 $ (89 ) $ 564,178 Income (loss) before income taxes (1)(2) 91,355 (3,730 ) 23,535 10,930 9,087 131,177 Total assets (3) 745,073 601,676 123,460 93,232 1,108,073 2,671,514 Three Months Ended July 1, 2018 Revenues $ 360,088 $ 62,057 $ 69,682 $ 35,212 $ (110 ) $ 526,929 Income (loss) before income taxes (1)(2) 91,159 (2,922 ) 20,352 10,308 1,115 120,012 Total assets (3) 765,484 597,293 107,199 77,638 1,384,106 2,931,720 Six Months Ended June 30, 2019 Revenues $ 715,751 $ 140,862 $ 131,627 $ 70,277 $ (240 ) $ 1,058,277 Income (loss) before income taxes (1)(2) 174,404 (9,025 ) 38,875 14,558 6,344 225,156 Total assets (3) 745,073 601,676 123,460 93,232 1,108,073 2,671,514 Six Months Ended July 1, 2018 Revenues $ 733,416 $ 110,891 $ 112,702 $ 57,719 $ (332 ) $ 1,014,396 Income (loss) before income taxes (1)(2) 179,238 (2,138 ) 26,240 10,772 1,719 215,831 Total assets (3) 765,484 597,293 107,199 77,638 1,384,106 2,931,720 (1) Included in Corporate and Other are: contingent consideration adjustments, severance charges, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations, acquisition related charges, and pension and postretirement plans actuarial losses. (2) Included in the income (loss) before income taxes for each of the segments are charges and credits related to restructuring and other and inventory charges. (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 Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 2,278 $ 1,613 $ 3,452 $ 3,779 Restructuring and other—employee severance 357 2,179 924 5,940 Included in the Industrial Automation segment are charges in the following line items in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Restructuring and other—acquisition related expenses and compensation $ 434 $ — $ 1,695 $ — Restructuring and other—employee severance 202 218 297 338 — — 416 — Included in the System Test segment are charges in the following line item in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 295 $ 256 $ 763 $ 576 Included in the Wireless Test segment are charges in the following line items in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 829 $ 627 $ 1,168 $ 1,463 Included in Corporate and Other are charges and credits in the following line items in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Restructuring and other—MiR contingent consideration adjustment $ (11,671 ) $ — $ (8,668 ) $ — Restructuring and other—Universal Robots contingent consideration adjustment — (3,500 ) — (8,468 ) Restructuring and other—acquisition related expenses and compensation — 2,544 — 3,318

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Shareholders' Equity	V. SHAREHOLDERS’ EQUITY Stock Repurchase Program In January 2018, Teradyne’s Board of Directors cancelled the December 2016 stock repurchase program and authorized a new stock repurchase program for up to $1.5 billion of common stock. Teradyne intends to repurchase $500 million in 2019. During the six months ended June 30, 2019, Teradyne repurchased 6.5 million shares of common stock for $247.2 million at an average price of $38.20 per share. The cumulative repurchases under the $1.5 billion stock repurchase program as of June 30, 2019 totaled 28.1 million shares of common stock for $1.1 billion at an average price per share of $38.09. During the six months ended July 1, 2018, Teradyne repurchased 8.8 million shares of common stock for $360.8 million at an average price of $40.82 per share. 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 2019 and May 2019, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.09 per share. Dividend payments for the three and six months ended June 30, 2019 were $15.4 million and $31.0 million, respectively. In January 2018 and May 2018, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.09 per share. Dividend payments for the three and six months ended July 1, 2018 were $17.1 million and $34.7 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.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events	W. SUBSEQUENT EVENTS Gregory Beecher retired as Vice President and Senior Advisor of Teradyne effective July 17, 2019 (the “Retirement Date”). In connection with the retirement, Teradyne entered into an agreement on July 17, 2019 Under the Retirement Agreement, Mr. Beecher’s unvested time-based restricted stock units and stock options granted prior to 2019 will continue to vest in accordance with their terms; unvested time-based restricted stock units and stock options granted in 2019 prior to the Retirement Date will continue to vest during the Non-Competition Period in a pro-rated amount based on the number of days that Mr. Beecher was employed during 2019; unvested, performance-based restricted stock units awarded prior to 2019 will continue to vest in accordance with their terms; unvested, performance-based restricted stock units awarded in 2019 will vest on the date the amount of shares underlying the performance-based restricted stock units are determined in a pro-rated amount of shares based on the number of days that Mr. Beecher was employed during the 365 calendar day period Teradyne will record a stock based compensation expense of approximately $2.5 million in the third quarter of 2019 related to the Retirement Agreement.

Accounting Policies (Policies)

Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
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 statement of such interim financial statements. Certain prior year amounts were reclassified to conform to the current year presentation. The December 31, 2018 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,
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.
Investment in Other Company	Investment in Other Company Teradyne holds an investment in a private company that develops and sells advanced wearable technology . Teradyne does not have the ability to exert significant influence over the company. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer on a quarterly basis. See Note D: “Acquisitions and Investment in Other Company.”
Leases	Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” right-of-use 2018-11, “Leases (Topic 842): Targeted Improvements,” under the transition guidance which included the carry-forward of historical lease classification. Adoption of ASC resulted in recording ROU assets and lease liabilities of approximately $ million and $ million, respectively. Operating lease liabilities were calculated using the discount rate on January , . The adoption of ASC did not have a material impact on beginning retained earnings, the consolidated statement of operations, cash flows, or earnings per share. Under ASC 842, a contract is or contains a lease when Teradyne has the right to control the use of an identified asset. Teradyne determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The commencement date of the lease is the date that the lessor makes an underlying asset available for use by Teradyne. As of June 30, 2019, Teradyne does not have material leases that have not yet commenced. Teradyne determines if the lease is operating or finance at the lease commencement date based upon the terms of the lease and the nature of the asset. The lease term used to calculate the lease liability includes options to extend or terminate the lease when it is reasonably certain that the option will be exercised. For leases commencing after January 1, 2019, the lease liability is measured at the present value of future lease payments, discounted using the discount rate for the lease at the commencement date. As Teradyne is typically unable to determine the implicit rate, Teradyne uses an incremental borrowing rate based on the lease term and economic environment at commencement date. Teradyne initially measures payments based on an index by using the applicable rate at lease commencement. Variable payments that do not depend on an index are not included in the lease liability and are recognized as they are incurred. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs, prepaid lease payments, and reduced by any lease incentives. Teradyne’s contracts often include non-lease non-lease

Acquisitions and Investment I_2

Acquisitions and Investment In Other Company (Tables)	6 Months Ended
	Jun. 30, 2019
Final Allocation of Purchase Price	The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 135,976 Intangible assets 80,670 Tangible assets acquired and liabilities assumed: Current assets 6,039 Non-current 1,336 Accounts payable and current liabilities (7,336 ) Long-term deferred tax liabilities (18,007 ) Other long-term liabilities (900 ) Total purchase price $ 197,778
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 Life (in thousands) (in years) Developed technology $ 58,900 7.0 Trademarks and tradenames 13,240 11.0 Customer relationships 8,500 2.5 Backlog 30 0.2 Total intangible assets $ 80,670 7.2
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 Six Months Ended July 1, 2018 July 1, 2018 (in thousands) Revenue $ 528,238 $ 1,021,194 Net income 101,780 186,787 Net income per common share: Basic $ 0.53 $ 0.97 Diluted $ 0.52 $ 0.94

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition	The following table provides information about disaggregated revenue by primary geographical market, major product line and timing of revenue recognition. For the Three Months Ended June 30, 2019 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated System Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 7,426 $ 8,059 $ 17,225 $ 3,703 $ 1,341 $ 16,938 $ 2,783 $ — $ 5,250 $ (89 ) $ 62,636 Over time 8,175 724 6,850 — 792 255 — 787 676 — 18,259 Europe, Middle East and Africa Point in time 9,819 2,016 211 — 2,974 26,545 5,041 — 620 — 47,226 Over time 5,212 284 505 — 1,615 399 — 477 48 — 8,540 Asia Pacific Point in time 247,885 43,909 163 27,672 6,848 18,532 2,681 — 33,366 — 381,056 Over time 36,566 3,293 329 2,310 775 279 — 9 1,242 — 44,803 Lease Revenue 1,530 — — — 94 — — — 34 — 1,658 Total $ 316,613 $ 58,285 $ 25,283 $ 33,685 $ 14,439 $ 62,948 $ 10,505 $ 1,273 $ 41,236 $ (89 ) $ 564,178 For the Three Months Ended July 1, 2018 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 12,111 $ 2,827 $ 15,256 $ 5 $ 1,429 $ 16,053 $ 1,199 $ — $ 4,716 $ (110 ) $ 53,486 Over time 8,934 710 6,237 — 795 327 — — 122 — 17,125 Europe, Middle East and Africa Point in time 10,227 847 447 — 4,849 26,616 2,000 — 26 — 45,012 Over time 5,689 254 539 — 1,713 526 — — 257 — 8,978 Asia Pacific Point in time 218,352 59,633 385 31,824 3,741 13,895 1,310 — 27,663 — 356,803 Over time 34,951 2,285 258 1,428 744 131 — — 2,103 — 41,900 Lease Revenue 3,268 — — — 32 — — — 325 — 3,625 Total $ 293,532 $ 66,556 $ 23,122 $ 33,257 $ 13,303 $ 57,548 $ 4,509 $ — $ 35,212 $ (110 ) $ 526,929 For the Six Months Ended June 30, 2019 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 15,403 $ 16,110 $ 32,007 $ 5,295 $ 4,595 $ 32,235 $ 6,322 $ — $ 7,340 $ (240 ) $ 119,067 Over time 16,365 1,436 13,300 — 1,521 501 — 1,047 827 — 34,997 Europe, Middle East and Africa Point in time 20,851 2,168 250 — 8,038 52,448 8,883 — 1,356 — 93,994 Over time 10,493 563 974 — 3,169 815 — 766 93 — 16,873 Asia Pacific Point in time 467,698 79,415 426 44,279 10,483 32,709 4,408 — 57,995 — 697,413 Over time 75,479 6,573 1,093 4,364 1,696 507 — 221 2,601 — 92,534 Lease Revenue 3,197 — — — 137 — — — 65 — 3,399 Total $ 609,486 $ 106,265 $ 48,050 $ 53,938 $ 29,639 $ 121,249 $ 19,613 $ 2,034 $ 70,277 $ (240 ) $ 1,058,277 For the Six Months Ended July 1, 2018 Semiconductor Test System Test Industrial Automation Wireless Corporate Consolidated SOC Memory Defense/ Aerospace Storage Production Universal Mobile Energid (in thousands) Americas Point in time $ 21,711 $ 5,691 $ 26,853 $ 284 $ 3,189 $ 30,190 $ 1,199 $ — $ 9,695 $ (332 ) $ 98,480 Over time 17,517 1,406 12,425 — 1,552 652 — — 233 — 33,785 Europe, Middle East and Africa Point in time 22,352 986 1,943 — 8,886 49,190 2,000 — 1,066 — 86,423 Over time 10,888 523 1,090 — 3,272 668 — — 484 — 16,925 Asia Pacific Point in time 446,543 125,904 487 41,946 5,603 25,478 1,310 — 41,329 — 688,600 Over time 68,173 4,607 466 2,961 1,479 204 — — 4,399 — 82,289 Lease Revenue 7,115 — — — 266 — — — 513 — 7,894 Total $ 594,299 $ 139,117 $ 43,264 $ 45,191 $ 24,247 $ 106,382 $ 4,509 $ — $ 57,719 $ (332 ) $ 1,014,396

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2019
Composition of Inventories, Net	Inventories, net consisted of the following at June 30, 2019 and December 31, 2018: June 30, December 31, (in thousands) Raw material $ 96,824 $ 89,365 Work-in-process 31,676 31,014 Finished goods 35,961 33,162 $ 164,461 $ 153,541

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and December 31, 2018. June 30, 2019 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 235,370 $ — $ — $ 235,370 Cash equivalents 223,150 36,587 — 259,737 Available-for-sale U.S. Treasury securities — 190,322 — 190,322 Commercial paper — 154,910 — 154,910 Corporate debt securities — 94,431 — 94,431 Certificates of deposit and time deposits — 19,723 — 19,723 U.S. government agency securities — 9,838 — 9,838 Debt mutual funds 3,299 — — 3,299 Non-U.S. — 388 — 388 Equity securities: Mutual funds 26,317 — — 26,317 $ 488,136 $ 506,199 $ — $ 994,335 Derivative assets — 34 — 34 Total $ 488,136 $ 506,233 $ — $ 994,369 Liabilities Contingent consideration $ — $ — $ 26,847 $ 26,847 Derivative liabilities — 324 — 324 Total $ — $ 324 $ 26,847 $ 27,171 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 458,520 $ 36,587 $ — $ 495,107 Marketable securities — 400,227 — 400,227 Long-term marketable securities 29,616 69,385 — 99,001 Prepayments — 34 — 34 Total $ 488,136 $ 506,233 $ — $ 994,369 Liabilities . Other current liabilities $ — $ 324 $ — $ 324 Contingent consideration — — 11,753 11,753 Long-term contingent consideration — — 15,094 15,094 Total $ — $ 324 $ 26,847 $ 27,171 December 31, 2018 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 312,512 $ — $ — $ 312,512 Cash equivalents 253,525 360,715 — 614,240 Available-for-sale U.S. Treasury securities — 109,721 — 109,721 Commercial paper — 86,117 — 86,117 Corporate debt securities — 40,020 — 40,020 U.S. government agency securities — 9,611 — 9,611 Certificates of deposit and time deposits — 7,604 — 7,604 Debt mutual funds 3,187 — — 3,187 Non-U.S. — 376 — 376 Equity securities: Mutual funds 21,191 — — 21,191 $ 590,415 $ 614,164 $ — $ 1,204,579 Derivative assets — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Contingent consideration $ — $ — $ 70,543 $ 70,543 Derivative liabilities — 514 — 514 Total $ — $ 514 $ 70,543 $ 71,057 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 566,037 $ 360,715 $ — $ 926,752 Marketable securities — 190,096 — 190,096 Long-term marketable securities 24,378 63,353 — 87,731 Prepayments — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Other accrued liabilities $ — $ 514 $ — $ 514 Contingent consideration — — 34,865 34,865 Long-term contingent consideration — — 35,678 35,678 Total $ — $ 514 $ 70,543 $ 71,057
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 six months ended June 30, 2019 and July 1, 2018 were as follows: For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, (in thousands) Balance at beginning of period $ 38,313 $ 15,581 $ 70,543 $ 45,102 Fair value adjustment (a) (11,672 ) (3,500 ) (8,701 ) (8,468 ) Foreign currency impact 206 (2,566 ) (405 ) (2,566 ) Payments (b) — — (34,590 ) (24,553 ) Acquisition of MiR — 51,399 — 51,399 Balance at end of period $ 26,847 $ 60,914 $ 26,847 $ 60,914 (a) In the three and six months ended June 30, 2019, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was decreased by $11.7 million and $8.7 million, respectively, primarily due to a decrease in the forecasted revenue. In the three and six months ended July 1, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of Universal Robots A/S (“Universal Robots”) was decreased by $ 3.5 (b) In the six months ended June 30, 2019, Teradyne paid $30.8 million and $3.8 million of contingent consideration for the earn-outs in connection with the acquisition of MiR and Universal Robots, respectively. In the six months ended July 1, 2018, Teradyne paid $24.6 million of contingent consideration for the earn-out in connection with the acquisition of Universal Robots.
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 June 30, 2019 Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent consideration (MiR) $ 26,847 Monte Carlo Simulation Revenue volatility 19.0 Discount rate 0.2%
Schedule of Carrying Amounts and Fair Values of Financial Instruments	The carrying amounts and fair values of Teradyne’s financial instruments at June 30, 2019 and December 31, 2018 were as follows: June 30, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 495,107 $ 495,107 $ 926,752 $ 926,752 Marketable securities 499,228 499,228 277,827 277,827 Derivative assets 34 34 79 79 Liabilities Contingent consideration 26,847 26,847 70,543 70,543 Derivative liabilities 324 324 514 514 Convertible debt (1) 387,243 747,213 379,981 547,113 (1) The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note, which includes the equity conversion features.
Schedule of Available-for-Sale Marketable Securities	The following table summarizes the composition of available-for-sale June 30, 2019 Available-for-Sale Fair Market Cost Unrealized Gain Unrealized (Loss) Fair Value Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 189,927 $ 668 $ (273 ) $ 190,322 $ 18,195 Commercial paper 154,903 9 (2 ) 154,910 10,322 Corporate debt securities 91,553 3,035 (157 ) 94,431 4,581 Certificates of deposit and time deposits 19,717 6 — 19,723 2,232 U.S. government agency securities 9,829 15 (6 ) 9,838 2,947 Debt mutual funds 3,187 112 — 3,299 — Non-U.S. 388 — — 388 — $ 469,504 $ 3,845 $ (438 ) $ 472,911 $ 38,277 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 399,852 $ 391 $ (16 ) $ 400,227 $ 21,708 Long-term marketable securities 69,652 3,454 (422 ) 72,684 16,569 $ 469,504 $ 3,845 $ (438 ) $ 472,911 $ 38,277 The following table summarizes the composition of available-for-sale December 31, 2018 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 110,969 $ 112 $ (1,360 ) $ 109,721 $ 75,040 Commercial paper 86,130 13 (26 ) 86,117 85,094 Corporate debt securities 41,133 432 (1,545 ) 40,020 24,767 U.S. government agency securities 9,646 1 (36 ) 9,611 7,077 Certificates of deposit and time deposits 7,604 — — 7,604 — Debt mutual funds 3,153 34 — 3,187 — Non-U.S. 376 — — 376 — $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 190,100 $ 88 $ (92 ) $ 190,096 $ 140,262 Long-term marketable securities 68,911 504 (2,875 ) 66,540 51,716 $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978
Contractual Maturities of Investments Held	The contractual maturities of investments in available-for-sale June 30, 2019 Cost Fair Market Value (in thousands) Due within one year $ 399,852 $ 400,227 Due after 1 year through 5 years 12,304 12,411 Due after 5 years through 10 years 14,101 14,156 Due after 10 years 40,060 42,818 Total $ 466,317 $ 469,612
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	The following table summarizes the fair value of derivative instruments as of June 30, 2019 and December 31, 2018: Balance Sheet Location June 30, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts – derivative assets Prepayments $ 34 $ 79 Foreign exchange contracts – Other current liabilities (324 ) (514 ) Total derivatives $ (290 ) $ (435 )
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 for the three and six months ended June 30, 2019 and July 1, 2018. Location of Losses (Gains) Recognized in Statement of Operations For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 239 $ 1,826 $ 4,173 $ 3,401 (1) The table does not reflect the corresponding gains and losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies. (2) For the three months ended June 30, 2019, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.3 million. For the six months ended June 30, 2019, net gains from the remeasurement of monetary assets and liabilities denominated in (3) For the three and six months ended July 1, 2018, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.9 million and $2.5 million, respectively.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Supplemental cash flow information related to leases	Supplemental cash flow information related to leases was as follows: For the Three Months For the Six Months June 30, 2019 June 30, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows: $ 4,993 $ 10,052 Right-of-use 9,675 15,412
Schedule of operating lease, maturity	Maturities of lease liabilities as of June 30, 2019 were as follows: Operating Lease (in thousands) 2019 $ 10,725 2020 19,177 2021 16,510 2022 12,226 2023 5,849 Thereafter 12,583 Total lease payments 77,070 Less imputed interest (12,569 ) Total lease liabilities $ 64,501
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2018, future non-cancelable Operating Lease (in thousands) 2019 $ 19,570 2020 18,293 2021 13,578 2022 9,693 2023 5,449 Thereafter 9,472 Total lease payments $ 76,055

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Components of Convertible Senior Notes	The below tables represent the key components of Teradyne’s convertible senior notes: June 30, December 31, (in thousands) Debt Principal $ 460,000 $ 460,000 Unamortized discount 72,757 80,019 Net Carrying amount of convertible debt $ 387,243 $ 379,981 For the Three Months For the Six Months June 30, July 1, June 30, July 1, (in thousands) Contractual interest expense on the coupon $ 1,438 $ 1,438 $ 2,875 $ 2,875 Amortization of the discount component recognized as interest expense 3,653 3,477 7,262 6,911 Total interest expense on the convertible debt $ 5,091 $ 4,915 $ 10,137 $ 9,786

Prepayments (Tables)

Prepayments (Tables)	6 Months Ended
	Jun. 30, 2019
Schedule of Prepayments and other assets	Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: June 30, 2019 December 31, 2018 (in thousands) Contract manufacturer and supplier prepayments $ 139,232 $ 131,642 Prepaid taxes 10,810 9,646 Prepaid maintenance and other services 9,935 8,487 Other prepayments 16,086 12,744 Total prepayments $ 176,063 $ 162,519

Deferred Revenue and Customer_2

Deferred Revenue and Customer Advances (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, (in thousands) Maintenance and training $ 60,331 $ 58,362 Extended warranty 28,716 27,422 Customer advances, undelivered performance obligations and other 38,155 24,677 Total deferred revenue and customer advances $ 127,202 $ 110,461

Product Warranty (Tables)

Product Warranty (Tables)	6 Months Ended
	Jun. 30, 2019
Other Accrued Liabilities	The warranty balance below is included in other accrued liabilities on the balance sheet. For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Balance at beginning of period $ 7,752 $ 7,548 $ 7,909 $ 8,200 Acquisition — 41 14 41 Accruals for warranties issued during the period 2,295 3,348 5,360 6,411 Accruals related to pre-existing 694 (34 ) 2,024 (173 ) Settlements made during the period (2,608 ) (3,767 ) (7,174 ) (7,343 ) Balance at end of period $ 8,133 $ 7,136 $ 8,133 $ 7,136
Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances	The balance below is included in short and long-term deferred revenue and customer advances on the balance sheet. For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Balance at beginning of period $ 27,242 $ 24,590 $ 27,422 $ 24,438 Deferral of new extended warranty revenue 5,476 6,701 11,296 11,839 Recognition of extended warranty deferred revenue (4,002 ) (5,320 ) (10,002 ) (10,306 ) Balance at end of period $ 28,716 $ 25,971 $ 28,716 $ 25,971

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Schedule of Estimated Fair Value of 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 Six Months Ended June 30, 2019 July 1, 2018 Risk-free interest rate 2.6 % 2.2 % Teradyne volatility-historical 31.9 % 26.8 % NYSE Composite Index volatility-historical 11.9 % 12.4 % Dividend yield 1.0 % 0.8 %
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 Six Months Ended June 30, 2019 July 1, 2018 Expected life (years) 5.0 5.0 Risk-free interest rate 2.5 % 2.4 % Volatility-historical 30.1 % 26.4 % Dividend yield 1.0 % 0.8 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2019
Changes in Accumulated Other Comprehensive (Loss) Income	Changes in accumulated other comprehensive income (loss), which are presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended June 30, 2019 Balance at December 31, 2018, net of tax of $0, $(521), $(1,081), respectively $ (12,523 ) $ (1,845 ) $ 1,328 $ (13,040 ) Other comprehensive income before reclassifications, net of tax of $0, $1,256, $0, respectively 983 4,637 — 5,620 Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(26), $(21), respectively — (97 ) (74 ) (171 ) Net current period other comprehensive income (loss), net of tax of $0, $1,230, $(21), respectively 983 4,540 (74 ) 5,449 Balance at June 30, 2019, net of tax of $0, $709, $(1,102), respectively $ (11,540 ) $ 2,695 $ 1,254 $ (7,591 ) Foreign Currency Translation Adjustments Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended July 1, 2018 Balance at December 31, 2017, net of tax of $0, $1,815, $(932), respectively $ 15,919 $ 1,362 $ 1,495 $ 18,776 Other comprehensive income (loss) before reclassifications, net of tax of $0, $(774), $0, respectively (18,781 ) (2,489 ) — (21,270 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $11, $(35), respectively — 1,469 (123 ) 1,346 Net current period other comprehensive income (loss), net of tax of $0, $(733), $(35), respectively (18,781 ) (1,020 ) (123 ) (19,924 ) Reclassification of income tax effects from the Tax Reform Act, net of tax of $0, $(691), $(78), respectively (a) — 691 78 769 Reclassification of unrealized gains on equity securities, net of tax of $0, $(902), $0, respectively (b) — (3,125 ) — (3,125 ) Balance as July 1, 2018, net of tax of $0, $(511), $(1,045), respectively $ (2,862 ) $ (2,092 ) $ 1,450 $ (3,504 ) (a) In the six months ended July 1, 2018, Teradyne early adopted the ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” (b) In the six months ended July 1, 2018, Teradyne adopted the ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.”
Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations	Reclassifications out of accumulated other comprehensive income (loss) to the statement of operations for the three and six months ended June 30, 2019 and July 1, 2018 were as follows: Details about Accumulated Other Comprehensive Income Components For the Three Months Ended For the Six Months Ended Affected Line Item in the Statements of Operations June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Available-for-sale Unrealized gains (losses), net of tax of $6, $68, $26, $(11), $ 27 $ 199 $ 97 $ (1,469 ) Interest income Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $11, $18, 37 61 74 123 (a) Total reclassifications, net of tax of $17, $86, $47, $24, respectively $ 64 $ 260 $ 171 $ (1,346 ) Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit. See Note R: “Retirement Plans.”

Goodwill and Acquired Intangi_2

Goodwill and Acquired Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by reportable segments for the six months ended June 30, 2019, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2018 Goodwill $ 363,358 $ 158,699 $ 361,819 $ 260,540 $ 1,144,416 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 363,358 10,516 7,976 — 381,850 Lemsys acquisition — — — 1,428 1,428 Foreign currency translation adjustment 626 — — 32 658 Balance at June 30, 2019 Goodwill 363,984 158,699 361,819 262,000 1,146,502 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 363,984 $ 10,516 $ 7,976 $ 1,460 $ 383,936
Schedule of Estimated Intangible Assets Amortization Expense	Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2019 (remainder) 18,745 2020 25,037 2021 14,778 2022 13,885 2023 13,410 Thereafter 23,639
Wireless Test
Schedule of Amortizable Intangible Assets	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet: June 30, 2019 Gross Carrying Amount (1)(2) Accumulated Amortization (2) Foreign Adjustment Net Carrying Amount (in thousands) Developed technology $ 337,198 $ (265,951 ) $ (4,035 ) $ 67,212 Customer relationships 100,313 (87,496 ) (285 ) 12,532 Tradenames and trademarks 64,670 (34,131 ) (789 ) 29,750 Total intangible assets $ 502,181 $ (387,578 ) $ (5,109 ) $ 109,494 December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Net Carrying Amount (in thousands) Developed technology $ 336,308 $ (252,080 ) $ (4,079 ) $ 80,149 Customer relationships 97,153 (83,448 ) (340 ) 13,365 Tradenames and trademarks 64,420 (31,653 ) (799 ) 31,968 Non-compete 320 (320 ) — — Backlog 30 (30 ) — — Total intangible assets $ 498,231 $ (367,531 ) $ (5,218 ) $ 125,482

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2019
Computation of Basic and Diluted Net Income (Loss) Per Common Share	The following table sets forth the computation of basic and diluted net income per common share: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 97,397 $ 101,037 $ 206,535 $ 188,010 Weighted average common shares-basic 171,241 190,730 172,387 192,992 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 4,364 2,643 3,275 3,520 Convertible note hedge warrant shares (2) 1,778 — 889 915 Restricted stock units 1,002 1,219 1,012 1,444 Stock options 183 274 202 298 Employee stock purchase plan 22 43 16 28 Dilutive potential common shares 7,349 4,179 5,394 6,205 Weighted average common shares-diluted 178,590 194,909 177,781 199,197 Net income per common share-basic $ 0.57 $ 0.53 $ 1.20 $ 0.97 Net income per common share-diluted $ 0.55 $ 0.52 $ 1.16 $ 0.94 (1) Incremental shares from 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 $ 31.70 (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 $39.78, multiplied by 14.5 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.

Retirement Plans (Tables)

Retirement Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Defined Benefit Pension Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three and six months ended June 30, 2019 and July 1, 2018, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended June 30, 2019 July 1, 2018 United States Foreign United States Foreign (in thousands) Service cost $ 399 $ 192 $ 545 $ 200 Interest cost 1,799 176 2,430 175 Expected return on plan assets (1,510 ) (7 ) (2,550 ) (5 ) Amortization of prior service cost — — 14 — Net actuarial loss (gain) 252 — (189 ) — Settlement loss — — 78 — Total net periodic pension cost $ 940 $ 361 $ 328 $ 370 For the Six Months Ended June 30, 2019 July 1, 2018 United States Foreign United States Foreign (in thousands) Service cost $ 804 $ 381 $ 1,116 $ 426 Interest cost 3,595 349 5,427 372 Expected return on plan assets (3,021 ) (14 ) (5,919 ) (10 ) Amortization of prior service cost — — 29 — Net actuarial loss (gain) 252 — (189 ) — Settlement loss — — 78 — Total net periodic pension cost $ 1,630 $ 716 $ 542 $ 788
Postretirement Benefit Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three and six months ended June 30, 2019 and July 1, 2018, Teradyne’s net periodic postretirement benefit cost was comprised of the following: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Service cost $ 11 $ 10 $ 20 $ 19 Interest cost 88 48 173 98 Amortization of prior service credit (48 ) (93 ) (95 ) (187 ) Net actuarial loss 196 40 196 40 Special termination benefits — 1,192 — 2,818 Total net periodic postretirement benefit cost $ 247 $ 1,197 $ 294 $ 2,788

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Reconciliation of Effective Tax Rate	A reconciliation of the United States federal statutory corporate tax rate to Teradyne’s effective tax rate was as follows: For the Three Months Ended For the Six Months Ended June 30, July 1, June 30, July 1, US statutory federal tax rate 21.0 % 21.0 % 21.0 % 21.0 % Discrete expense related to U.S. transition tax 11.2 % 0.0 % 6.5 % 0.0 % International provisions of the U.S. Tax Cuts and Jobs Act of 2017 0.8 % (1.4 %) 0.8 % (1.4 %) Discrete benefit related to equity compensation (0.5 %) (0.1 %) (2.0 %) (3.5 %) Foreign taxes (4.9 %) (3.4 %) (4.9 %) (3.4 %) Tax credits (2.5 %) (2.1 %) (2.5 %) (2.1 %) Discrete benefit related to release of reserves for uncertain tax positions (0.1 %) 0.0 % (12.9 %) 0.0 % Other, net 0.8 % 1.8 % 2.3 % 2.3 % Effective tax rate 25.8 % 15.8 % 8.3 % 12.9 %

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Information	Segment information for the three and six months ended June 30, 2019 and July 1, 2018 is as follows: Semiconductor Test Industrial Automation System Test Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended June 30, 2019 Revenues $ 374,898 $ 74,726 $ 73,407 $ 41,236 $ (89 ) $ 564,178 Income (loss) before income taxes (1)(2) 91,355 (3,730 ) 23,535 10,930 9,087 131,177 Total assets (3) 745,073 601,676 123,460 93,232 1,108,073 2,671,514 Three Months Ended July 1, 2018 Revenues $ 360,088 $ 62,057 $ 69,682 $ 35,212 $ (110 ) $ 526,929 Income (loss) before income taxes (1)(2) 91,159 (2,922 ) 20,352 10,308 1,115 120,012 Total assets (3) 765,484 597,293 107,199 77,638 1,384,106 2,931,720 Six Months Ended June 30, 2019 Revenues $ 715,751 $ 140,862 $ 131,627 $ 70,277 $ (240 ) $ 1,058,277 Income (loss) before income taxes (1)(2) 174,404 (9,025 ) 38,875 14,558 6,344 225,156 Total assets (3) 745,073 601,676 123,460 93,232 1,108,073 2,671,514 Six Months Ended July 1, 2018 Revenues $ 733,416 $ 110,891 $ 112,702 $ 57,719 $ (332 ) $ 1,014,396 Income (loss) before income taxes (1)(2) 179,238 (2,138 ) 26,240 10,772 1,719 215,831 Total assets (3) 765,484 597,293 107,199 77,638 1,384,106 2,931,720 (1) Included in Corporate and Other are: contingent consideration adjustments, severance charges, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations, acquisition related charges, and pension and postretirement plans actuarial losses. (2) Included in the income (loss) before income taxes for each of the segments are charges and credits related to restructuring and other and inventory charges. (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 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 Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 2,278 $ 1,613 $ 3,452 $ 3,779 Restructuring and other—employee severance 357 2,179 924 5,940
Industrial Automation
Schedule of Segment Reporting Information by Segment Charges	Included in the Industrial Automation segment are charges in the following line items in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Restructuring and other—acquisition related expenses and compensation $ 434 $ — $ 1,695 $ — Restructuring and other—employee severance 202 218 297 338 — — 416 —
System Test
Schedule of Segment Reporting Information by Segment Charges	Included in the System Test segment are charges in the following line item in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 295 $ 256 $ 763 $ 576
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 Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Cost of revenues—inventory charge $ 829 $ 627 $ 1,168 $ 1,463
Corporate and Other [Member]
Schedule of Segment Reporting Information by Segment Charges	Included in Corporate and Other are charges and credits in the following line items in the statements of operations: For the Three Months Ended For the Six Months Ended June 30, 2019 July 1, 2018 June 30, 2019 July 1, 2018 (in thousands) Restructuring and other—MiR contingent consideration adjustment $ (11,671 ) $ — $ (8,668 ) $ — Restructuring and other—Universal Robots contingent consideration adjustment — (3,500 ) — (8,468 ) Restructuring and other—acquisition related expenses and compensation — 2,544 — 3,318

Acquisitions and Investment I_3

Acquisitions and Investment In Other Company - Additional Information (Detail) - USD ($)	Apr. 25, 2018	Feb. 26, 2018	Jan. 30, 2019	Jul. 01, 2018	Jul. 01, 2018	Jun. 30, 2019	Jun. 03, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Contingent consideration								$ 30,800,000
Goodwill						383,936,000		381,850,000
Estimate of Fair Value Measurement [Member]
Business Acquisition [Line Items]
Contingent consideration						26,847,000		$ 70,543,000
Revenues				$ 400,000	$ 400,000
Real War In [Member]
Business Acquisition [Line Items]
Equity Method Investments							$ 15,000,000
Investments, Fair Value Disclosure						15,000,000
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total preliminary purchase price	$ 197,778,000
Cash paid to acquire outstanding common and preferred stock	145,200,000
Contingent consideration	52,600,000
Arrangement range of outcomes value high						$ 84,100,000
Goodwill, not deductible for tax purposes	136,000,000
Net income				101,780,000	186,787,000
Goodwill	$ 135,976,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years 2 months 12 days
Mobile Industrial Robots (MiR) | Acquisition Related Costs
Business Acquisition [Line Items]
Net income				$ 2,300,000	$ 2,900,000
Energid Technologies Corporation
Business Acquisition [Line Items]
Total preliminary purchase price		$ 27,600,000
Goodwill		14,400,000
Acquired value of intangible assets		$ 12,300,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		7 years 8 months 12 days
Net tangible assets		$ 1,000,000
Lemsys [Member]
Business Acquisition [Line Items]
Total preliminary purchase price			$ 1,400,000
Total preliminary purchase price			9,100,000
Acquired value of intangible assets			$ 4,600,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years 2 months 12 days
Net tangible assets			$ 3,100,000

Final Allocation of Purchase Pr

Final Allocation of Purchase Price (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Apr. 25, 2018
Business Acquisition [Line Items]
Goodwill	$ 383,936	$ 381,850
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Goodwill			$ 135,976
Intangible assets			80,670
Current assets			6,039
Non-current assets			1,336
Accounts payable and current liabilities			(7,336)
Long-term deferred tax liabilities			(18,007)
Other long-term liabilities			(900)
Total purchase price			$ 197,778

Components of Intangible Assets

Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date (Detail) - Mobile Industrial Robots (MiR) $ in Thousands	Apr. 25, 2018USD ($)
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 80,670
Total intangible assets, estimated useful life, years	7 years 2 months 12 days
Developed technology
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 58,900
Total intangible assets, estimated useful life, years	7 years
Trademarks and tradenames
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 13,240
Total intangible assets, estimated useful life, years	11 years
Customer Relationships
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 8,500
Total intangible assets, estimated useful life, years	2 years 6 months
Customer backlog
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 30
Total intangible assets, estimated useful life, years	2 months 12 days

Pro Forma Results Under Acquisi

Pro Forma Results Under Acquisition (Detail) - Mobile Industrial Robots (MiR) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 01, 2018	Jul. 01, 2018
Business Acquisition [Line Items]
Revenue	$ 528,238	$ 1,021,194
Net income	$ 101,780	$ 186,787
Net income per common share, basic	$ 0.53	$ 0.97
Net income per common share, diluted	$ 0.52	$ 0.94

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Revenue recognized in accordance with ASC 606	$ 564,178	$ 526,929	$ 1,058,277	$ 1,014,396
Revenue on leases	1,700	3,600	3,400	7,900
Deferred Revenue And Customer Advances	13,300	24,700	33,400	46,500
Trade Accounts Receivable	$ 82,100	$ 8,900	$ 82,100	8,900
Short-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	72.00%		72.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			12 months
Long-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	22.00%		22.00%
Long-term Contract with Customer [Member] | Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			3 years
Long-term Contract with Customer [Member] | Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			1 year
Accounting Standards Update 2014-09 [Member]
Revenue recognized in accordance with ASC 606	$ 562,500		$ 1,054,900	$ 1,006,500

Disaggregated Revenue by Primar

Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Disaggregation of Revenue [Line Items]
Total	$ 564,178	$ 526,929	$ 1,058,277	$ 1,014,396
Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	374,898	360,088	715,751	733,416
System Test
Disaggregation of Revenue [Line Items]
Total	73,407	69,682	131,627	112,702
Industrial Automation
Disaggregation of Revenue [Line Items]
Total	74,726	62,057	140,862	110,891
Wireless Test
Disaggregation of Revenue [Line Items]
Total	41,236	35,212	70,277	57,719
Corporate and Other
Disaggregation of Revenue [Line Items]
Total	(89)	(110)	(240)	(332)
Americas | Point in Time
Disaggregation of Revenue [Line Items]
Total	62,636	53,486	119,067	98,480
Americas | Point in Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	5,250	4,716	7,340	9,695
Americas | Point in Time | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	(89)	(110)	(240)	(332)
Americas | Over Time
Disaggregation of Revenue [Line Items]
Total	18,259	17,125	34,997	33,785
Americas | Over Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	676	122	827	233
Europe, Middle East and Africa | Point in Time
Disaggregation of Revenue [Line Items]
Total	47,226	45,012	93,994	86,423
Europe, Middle East and Africa | Point in Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	620	26	1,356	1,066
Europe, Middle East and Africa | Over Time
Disaggregation of Revenue [Line Items]
Total	8,540	8,978	16,873	16,925
Europe, Middle East and Africa | Over Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	48	257	93	484
Asia Pacific
Disaggregation of Revenue [Line Items]
Total	1,658	3,625	3,399	7,894
Asia Pacific | Wireless Test
Disaggregation of Revenue [Line Items]
Total	34	325	65	513
Asia Pacific | Point in Time
Disaggregation of Revenue [Line Items]
Total	381,056	356,803	697,413	688,600
Asia Pacific | Point in Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	33,366	27,663	57,995	41,329
Asia Pacific | Over Time
Disaggregation of Revenue [Line Items]
Total	44,803	41,900	92,534	82,289
Asia Pacific | Over Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	1,242	2,103	2,601	4,399
SOC | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	316,613	293,532	609,486	594,299
SOC | Americas | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	7,426	12,111	15,403	21,711
SOC | Americas | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	8,175	8,934	16,365	17,517
SOC | Europe, Middle East and Africa | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	9,819	10,227	20,851	22,352
SOC | Europe, Middle East and Africa | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	5,212	5,689	10,493	10,888
SOC | Asia Pacific | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	1,530	3,268	3,197	7,115
SOC | Asia Pacific | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	247,885	218,352	467,698	446,543
SOC | Asia Pacific | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	36,566	34,951	75,479	68,173
Memory | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	58,285	66,556	106,265	139,117
Memory | Americas | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	8,059	2,827	16,110	5,691
Memory | Americas | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	724	710	1,436	1,406
Memory | Europe, Middle East and Africa | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	2,016	847	2,168	986
Memory | Europe, Middle East and Africa | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	284	254	563	523
Memory | Asia Pacific | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	43,909	59,633	79,415	125,904
Memory | Asia Pacific | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	3,293	2,285	6,573	4,607
Defense/Aerospace | System Test
Disaggregation of Revenue [Line Items]
Total	25,283	23,122	48,050	43,264
Defense/Aerospace | Americas | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	17,225	15,256	32,007	26,853
Defense/Aerospace | Americas | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	6,850	6,237	13,300	12,425
Defense/Aerospace | Europe, Middle East and Africa | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	211	447	250	1,943
Defense/Aerospace | Europe, Middle East and Africa | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	505	539	974	1,090
Defense/Aerospace | Asia Pacific | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	163	385	426	487
Defense/Aerospace | Asia Pacific | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	329	258	1,093	466
Storage Test | System Test
Disaggregation of Revenue [Line Items]
Total	33,685	33,257	53,938	45,191
Storage Test | Americas | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	3,703	5	5,295	284
Storage Test | Asia Pacific | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	27,672	31,824	44,279	41,946
Storage Test | Asia Pacific | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	2,310	1,428	4,364	2,961
Production Board Test | System Test
Disaggregation of Revenue [Line Items]
Total	14,439	13,303	29,639	24,247
Production Board Test | Americas | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	1,341	1,429	4,595	3,189
Production Board Test | Americas | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	792	795	1,521	1,552
Production Board Test | Europe, Middle East and Africa | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	2,974	4,849	8,038	8,886
Production Board Test | Europe, Middle East and Africa | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	1,615	1,713	3,169	3,272
Production Board Test | Asia Pacific | System Test
Disaggregation of Revenue [Line Items]
Total	94	32	137	266
Production Board Test | Asia Pacific | Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	6,848	3,741	10,483	5,603
Production Board Test | Asia Pacific | Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	775	744	1,696	1,479
Universal Robots (UR) | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	62,948	57,548	121,249	106,382
Universal Robots (UR) | Americas | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	16,938	16,053	32,235	30,190
Universal Robots (UR) | Americas | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	255	327	501	652
Universal Robots (UR) | Europe, Middle East and Africa | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	26,545	26,616	52,448	49,190
Universal Robots (UR) | Europe, Middle East and Africa | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	399	526	815	668
Universal Robots (UR) | Asia Pacific | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	18,532	13,895	32,709	25,478
Universal Robots (UR) | Asia Pacific | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	279	131	507	204
Mobile Industrial Robots (MiR) | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	10,505	4,509	19,613	4,509
Mobile Industrial Robots (MiR) | Americas | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	2,783	1,199	6,322	1,199
Mobile Industrial Robots (MiR) | Europe, Middle East and Africa | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	5,041	2,000	8,883	2,000
Mobile Industrial Robots (MiR) | Asia Pacific | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	2,681	$ 1,310	4,408	$ 1,310
Energid Technologies Corporation | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	1,273		2,034
Energid Technologies Corporation | Americas | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	787		1,047
Energid Technologies Corporation | Europe, Middle East and Africa | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	477		766
Energid Technologies Corporation | Asia Pacific | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	$ 9		$ 221

Composition of Inventories, Net

Composition of Inventories, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Inventory [Line Items]
Raw material	$ 96,824	$ 89,365
Work-in-process	31,676	31,014
Finished goods	35,961	33,162
Inventories, net	$ 164,461	$ 153,541

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Inventory [Line Items]
Inventory reserves	$ 102.6	$ 100.8

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 31, 2018
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized gain	$ 100,000	$ 100,000	$ 200,000	$ 400,000
Available-for-sale securities, realized loss	100,000			1,500,000
Available-for-sale marketable securities, Fair Market Value of Investments in debt securities with Unrealized Losses	38,277,000		38,277,000		$ 191,978,000
Fair market value of investments with unrealized losses greater than one year	22,700,000		22,700,000		28,500,000
Aggregate loss of investments with unrealized losses greater than one year	400,000		400,000		1,600,000
Fair market value of investments with unrealized losses less than one year	15,600,000		15,600,000		163,500,000
Aggregate loss of investments with unrealized losses less than one year	100,000		100,000		1,400,000
Unrealized Gain (loss) on contracts	1,300,000	1,900,000	1,900,000	2,500,000
Equity securities unrealized gain loss	900,000	$ 400,000	3,700,000	$ 400,000
Debt Mutual Funds
Financial Instruments and Fair Value [Line Items]
Available for sale securities with out contractual maturity date	3,300,000		3,300,000
Mobile Industrial Robots (MiR)
Financial Instruments and Fair Value [Line Items]
Maximum amount of contingent consideration paid for acquisition	$ 84,100,000		84,100,000
Foreign Exchange Contracts
Financial Instruments and Fair Value [Line Items]
Unrealized Gain (loss) on contracts			$ 143,300,000		$ 163,100,000

Schedule of Fair Value of Finan

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents
Available for sale securities	472,911	$ 256,636
Available for sale equity securities
Total
Contingent consideration		30,800
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	190,322	109,721
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	154,910	86,117
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	94,431	40,020
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	19,723	7,604
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	9,838	9,611
Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	3,299	3,187
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	388	376
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	994,335	1,204,579
Derivative assets	34	79
Total	994,369	1,204,658
Contingent consideration	26,847	70,543
Derivative liabilities	324	514
Total	27,171	71,057
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	235,370	312,512
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	259,737	614,240
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	190,322	109,721
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	154,910	86,117
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	94,431	40,020
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	19,723	7,604
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	9,838	9,611
Fair Value, Measurements, Recurring | Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	3,299	3,187
Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	388	376
Fair Value, Measurements, Recurring | Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	26,317	21,191
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	488,136	590,415
Total	488,136	590,415
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	235,370	312,512
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	223,150	253,525
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	3,299	3,187
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	26,317	21,191
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	506,199	614,164
Derivative assets	34	79
Total	506,233	614,243
Derivative liabilities	324	514
Total	324	514
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	36,587	360,715
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	190,322	109,721
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	154,910	86,117
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	94,431	40,020
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	19,723	7,604
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	9,838	9,611
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	388	376
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration	26,847	70,543
Total	$ 26,847	$ 70,543

Schedule of Reported Financial

Schedule of Reported Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 994,369	$ 1,204,658
Liabilities	27,171	71,057
Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	324	514
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	495,107	926,752
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	400,227	190,096
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	99,001	87,731
Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	34	79
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	11,753	34,865
Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	15,094	35,678
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	488,136	590,415
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	458,520	566,037
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	29,616	24,378
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	506,233	614,243
Liabilities	324	514
Significant Other Observable Inputs (Level 2) | Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	324	514
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	36,587	360,715
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	400,227	190,096
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	69,385	63,353
Significant Other Observable Inputs (Level 2) | Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	34	79
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	26,847	70,543
Significant Unobservable Inputs (Level 3) | Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	11,753	34,865
Significant Unobservable Inputs (Level 3) | Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	$ 15,094	$ 35,678

Schedule of Changes in Fair Val

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period		$ 38,313	$ 15,581	$ 70,543	$ 45,102
Acquisition of MiR	[1]	(11,672)	(3,500)	(8,701)	(8,468)
Foreign currency impact		206	(2,566)	(405)	(2,566)
Payments	[2]			(34,590)	(24,553)
Fair value adjustment	[1]		51,399		51,399
Balance at end of period		$ 26,847	$ 60,914	$ 26,847	$ 60,914
[1]	In the three and six months ended June 30, 2019, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was decreased by $11.7 million and $8.7 million, respectively, primarily due to a decrease in the forecasted revenue. In the three and six months ended July 1, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of Universal Robots A/S (“Universal Robots”) was decreased by $3.5 million and $8.5 million, respectively, primarily due to a decrease in forecasted revenue.
[2]	In the six months ended June 30, 2019, Teradyne paid $30.8 million and $3.8 million of contingent consideration for the earn-outs in connection with the acquisition of MiR and Universal Robots, respectively. In the six months ended July 1, 2018, Teradyne paid $24.6 million of contingent consideration for the earn-out in connection with the acquisition of Universal Robots.

Schedule of Changes in Fair V_2

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			$ 27,615	$ 13,571
Increase (decrease) in contingent consideration	$ 11,700	$ 3,500	(8,701)	$ (8,468)
Universal Robots (UR)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	3,500		8,500
Increase (decrease) in contingent consideration		$ 24,600
Universal Robots (UR) | Payment One [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			11,700
Universal Robots (UR) | Payment Two [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			8,700
MiR
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Increase (decrease) in contingent consideration	$ 30,800		3,800
MiR | Payment One [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			11,700
MiR | Payment Two [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			$ 8,700

Quantitative Information Associ

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Apr. 25, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration		$ 30,800
Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration			$ 52,600
Monte Carlo Simulation | Revenue for the period July 1, 2015-December 31, 2018 | Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Target achievement, volatility	19.00%
Discount rate	0.20%
Monte Carlo Simulation | Revenue for the period July 1, 2015-December 31, 2018 | Significant Unobservable Inputs (Level 3) | Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration	$ 26,847

Schedule of Carrying Amounts an

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents
Marketable securities		472,911	$ 256,636
Contingent consideration			30,800
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		495,107	926,752
Marketable securities		499,228	277,827
Derivative assets		34	79
Contingent consideration		26,847	70,543
Derivative liabilities		324	514
Convertible debt	[1]	387,243	379,981
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		495,107	926,752
Marketable securities		499,228	277,827
Derivative assets		34	79
Contingent consideration		26,847	70,543
Derivative liabilities		324	514
Convertible debt	[1]	$ 747,213	$ 547,113
[1]	The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note, which includes the equity conversion features.

Schedule of Available for Sale

Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 469,504	$ 259,011
Available-for-sale marketable securities, Unrealized Gain	3,845	592
Available-for-sale marketable securities, Unrealized (Loss)	(438)	(2,967)
Available-for-sale marketable securities, Fair Market Value	472,911	256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	38,277	191,978
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	189,927	110,969
Available-for-sale marketable securities, Unrealized Gain	668	112
Available-for-sale marketable securities, Unrealized (Loss)	(273)	(1,360)
Available-for-sale marketable securities, Fair Market Value	190,322	109,721
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	18,195	75,040
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	154,903	86,130
Available-for-sale marketable securities, Unrealized Gain	9	13
Available-for-sale marketable securities, Unrealized (Loss)	(2)	(26)
Available-for-sale marketable securities, Fair Market Value	154,910	86,117
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	10,322	85,094
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	91,553	41,133
Available-for-sale marketable securities, Unrealized Gain	3,035	432
Available-for-sale marketable securities, Unrealized (Loss)	(157)	(1,545)
Available-for-sale marketable securities, Fair Market Value	94,431	40,020
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	4,581	24,767
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	19,717	7,604
Available-for-sale marketable securities, Unrealized Gain	6
Available-for-sale marketable securities, Fair Market Value	19,723	7,604
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	2,232
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	9,829	9,646
Available-for-sale marketable securities, Unrealized Gain	15	1
Available-for-sale marketable securities, Unrealized (Loss)	(6)	(36)
Available-for-sale marketable securities, Fair Market Value	9,838	9,611
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	2,947	7,077
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	3,187	3,153
Available-for-sale marketable securities, Unrealized Gain	112	34
Available-for-sale marketable securities, Fair Market Value	3,299	3,187
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	388	376
Available-for-sale marketable securities, Fair Market Value	$ 388	$ 376

Schedule of Reported Available

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 469,504	$ 259,011
Available-for-sale marketable securities, Unrealized Gain	3,845	592
Available-for-sale marketable securities, Unrealized (Loss)	(438)	(2,967)
Available-for-sale marketable securities, Fair Market Value	472,911	256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	38,277	191,978
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	399,852	190,100
Available-for-sale marketable securities, Unrealized Gain	391	88
Available-for-sale marketable securities, Unrealized (Loss)	(16)	(92)
Available-for-sale marketable securities, Fair Market Value	400,227	190,096
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	21,708	140,262
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	69,652	68,911
Available-for-sale marketable securities, Unrealized Gain	3,454	504
Available-for-sale marketable securities, Unrealized (Loss)	(422)	(2,875)
Available-for-sale marketable securities, Fair Market Value	72,684	66,540
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 16,569	$ 51,716

Contractual Maturities of Inves

Contractual Maturities of Investments in Debt Securities Held (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 399,852
Due after 1 year through 5 years, cost	12,304
Due after 5 years through 10 years, cost	14,101
Due after 10 years, cost	40,060
Total, cost	466,317
Due within one year, fair market value	400,227
Due after 1 year through 5 years, fair market value	12,411
Due after 5 years through 10 years, fair market value	14,156
Due after 10 years, fair maket value	42,818
Total, fair market value	$ 469,612

Schedule of Derivative Instrume

Schedule of Derivative Instruments in Statement of Financial Position at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets (liabilities), net	$ (290)	$ (435)
Not Designated as Hedging Instrument | Foreign currency forward contracts | Prepayments
Derivatives, Fair Value [Line Items]
Derivative assets	34	79
Not Designated as Hedging Instrument | Foreign currency forward contracts | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (324)	$ (514)

Schedule of Effect of Derivativ

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Losses (Gains) on derivatives recognized in statements of operations	$ 239	$ 1,826	$ 4,173	$ 3,401

Schedule of Effect of Derivat_2

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on foreign currency transactions	$ 1.3	$ 1.9	$ 1.9	$ 2.5

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019	Feb. 28, 2016
Total lease expense	$ 8,900	$ 17,100
Variable lease costs	2,600	5,000
Operating Lease, Right-of-Use Asset	56,315	56,315	$ 50,100	$ 50,100
Operating Lease, Liability	$ 64,501	$ 64,501	$ 54,300	$ 54,300
Operating Lease, Weighted Average Remaining Lease Term	4 years 8 months 12 days	4 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	5.20%	5.20%
Short-term Lease, Cost	$ 800	$ 1,500

Supplemental Cash Flow Informat

Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows	$ 4,993	$ 10,052
Right-of-use assets obtained in exchange for new lease obligations	$ 9,675	$ 15,412

Schedule of Operating Lease, Ma

Schedule of Operating Lease, Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Feb. 28, 2016
2019	$ 10,725
2020	19,177
2021	16,510
2022	12,226
2023	5,849
Thereafter	12,583
Total lease payments	77,070
Less imputed interest	(12,569)
Total lease liabilities	64,501	$ 54,300	$ 54,300
2019	19,570
2020	18,293
2021	13,578
2022	9,693
2023	5,449
Thereafter	9,472
Total lease payments	$ 76,055

Debt - Additional Information (

Debt - Additional Information (Detail) $ / shares in Units, $ in Thousands, shares in Millions	Dec. 12, 2016USD ($)Customershares	Jun. 30, 2019USD ($)$ / shares	Jun. 30, 2019USD ($)$ / shares	Jul. 01, 2018USD ($)	Dec. 31, 2018USD ($)shares	Dec. 31, 2016USD ($)$ / shares	Apr. 27, 2015USD ($)
Debt Instrument
Repurchase of common stock			$ 247,222	$ 360,795
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Aggregate principal amount	$ 460,000	$ 460,000	$ 460,000		$ 460,000
Debt instrument, interest rate, stated percentage	1.25%
Debt instrument, net proceeds after issuance costs	$ 450,800
Payment for net cost of convertible note hedges net of warrant proceeds	33,000
Repurchase of common stock	$ 50,100
Repurchase of stock, shares | shares	2
Senior notes maturity date	Dec. 15, 2023
Debt instrument, frequency of periodic payment	payable semiannually in arrears on June 15 and December 15 of each year
Debt instrument, date of first required payment	Jun. 15, 2017
Debt instrument, conversion option expiration date	Sep. 15, 2023
Debt instrument conversion price | $ / shares		$ 31.70	$ 31.70			$ 31.70
Shares that would be issued upon conversion | shares					14.5
Strike price per share of warrant | $ / shares		$ 39.78
Debt instrument, convertible, carrying amount of equity component		$ 100,800	$ 100,800
Financing cost		4,800	$ 4,800			$ 7,200
Debt issuance costs, amortization period			7 years
Unamortized discount		$ 72,800	$ 72,800
Debt Instrument, convertible, remaining discount amortization period			4 years 6 months
Value of notes converted			$ 695,200
1.25% Convertible Senior Unsecured Notes Due December 15, 2023 | Conversion option one
Debt Instrument
Trading days measurement period | Customer	20
Consecutive trading days measurement period | Customer	30
Percentage of conversion price	130.00%
1.25% Convertible Senior Unsecured Notes Due December 15, 2023 | Conversion option two
Debt Instrument
Trading days measurement period | Customer	5
Consecutive trading days measurement period | Customer	5
Percentage of closing sale price of common stock and conversion rate product	98.00%
Revolving Credit Facility | Maximum
Debt Instrument
Credit facility, borrowing capacity							$ 350,000

Components of Convertible Senio

Components of Convertible Senior Notes (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Dec. 12, 2016
Debt Instrument
Net carrying amount of convertible debt	$ 387,243	$ 379,981
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Debt principal	460,000	460,000	$ 460,000
Unamortized discount	72,757	80,019
Net carrying amount of convertible debt	$ 387,243	$ 379,981

Interest Expense on Convertible

Interest Expense on Convertible Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Debt Instrument
Contractual interest expense on the coupon	$ 1,438	$ 1,438	$ 2,875	$ 2,875
Amortization of the discount component and debt issue fees recognized as interest expense	3,653	3,477	7,262	6,911
Total interest expense on the convertible debt	$ 5,091	$ 4,915	$ 10,137	$ 9,786

Schedule of Prepayments and Oth

Schedule of Prepayments and Other Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Prepaid And Other Current Assets [Line Items]
Contract manufacturer and supplier prepayments	$ 139,232	$ 131,642
Prepaid taxes	10,810	9,646
Prepaid maintenance and other services	9,935	8,487
Other prepayments	16,086	12,744
Total prepayments	$ 176,063	$ 162,519

Deferred Revenue and Customer_3

Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jul. 01, 2018	Apr. 01, 2018	Jan. 01, 2018
Deferred Revenue Arrangement
Maintenance and training	$ 60,331		$ 58,362
Extended warranty	28,716	$ 27,242	27,422	$ 25,971	$ 24,590	$ 24,438
Customer advances, undelivered performance obligations and other	38,155		24,677
Total deferred revenue and customer advances	$ 127,202		$ 110,461

Warranty Accrual Included in Ot

Warranty Accrual Included in Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 7,752	$ 7,548	$ 7,909	$ 8,200
Acquisition		41	14	41
Accruals for warranties issued during the period	2,295	3,348	5,360	6,411
Accruals related to pre-existing warranties	694	(34)	2,024	(173)
Settlements made during the period	(2,608)	(3,767)	(7,174)	(7,343)
Balance at end of period	$ 8,133	$ 7,136	$ 8,133	$ 7,136

Extended Product Warranty of Sh

Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 27,242	$ 24,590	$ 27,422	$ 24,438
Deferral of new extended warranty revenue	5,476	6,701	11,296	11,839
Recognition of extended warranty deferred revenue	(4,002)	(5,320)	(10,002)	(10,306)
Balance at end of period	$ 28,716	$ 25,971	$ 28,716	$ 25,971

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - $ / shares shares in Millions	1 Months Ended		6 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Estimated annual dividend amount per share			$ 0.36	$ 0.36
Stock price	$ 37.95				$ 47.70
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal annual installments			4 years
Percentage of common stock price paid			100.00%
Stock options term			7 years
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 annual installments			4 years
Restricted Stock Units | Director
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal annual installments			1 year
Percentage of awards vesting on the first anniversary of grant date			100.00%
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			60 years
Minimum years of service for retirement to be eligible for PRSUs			10 years
Restricted stock unit awards granted			0.1	0.1
Weighted average grant date fair value of restricted stock units granted			$ 51.51	$ 54.85
Stock price	$ 37.95				$ 47.70
TSR Performance-Based Restricted Stock Units | Measurement Input, Expected Dividend Payment [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Estimated annual dividend amount per share			$ 0.36	$ 0.36
TSR Performance-Based Restricted Stock Units | Share-based Compensation Award, Tranche One
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 | Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved	0.00%
PBIT Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Total shareholder return performance measurement period	3 years
Restricted stock unit awards granted			0.1	0.1
Weighted average grant date fair value of restricted stock units granted			$ 36.88	$ 46.62
PBIT Performance-Based Restricted Stock Units | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved		200.00%
PBIT Performance-Based Restricted Stock Units | Share-based Compensation Award, Tranche Two
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 | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted			0.7	0.6
Weighted average grant date fair value of restricted stock units granted			$ 36.10
Weighted average grant date fair value of restricted stock units granted				$ 46.38
Service-Based Restricted Stock Units | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted				0.1
Weighted average grant date fair value of restricted stock units granted				$ 12.17
Service-Based Restricted Stock Units | Non Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted			0.1	0.1
Weighted average grant date fair value of restricted stock units granted			$ 48.03	$ 35.81
Service Based Stock Options | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value of restricted stock units granted			$ 10.61
Number options granted during the period			0.1

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	6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	2.60%	2.20%
Expected historical volatility	31.90%	26.80%
Dividend yield	1.00%	0.80%
New York Stock Exchange Composite Index
Share-based Compensation Arrangement by Share-based Payment Award
Expected historical volatility	11.90%	12.40%

Schedule of Estimated Fair Va_2

Schedule of Estimated Fair Value of Stock Options Grant Using Black Scholes Option Pricing Model (Detail) - Stock Options	6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Expected life (years)	5 years	5 years
Risk-free interest rate	2.50%	2.40%
Volatility-historical	30.10%	26.40%
Dividend yield	1.00%	0.80%

Changes in Accumulated Other Co

Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		$ 1,470,228	$ 1,904,983	$ 1,522,354	$ 1,953,646
Amounts reclassified from accumulated other comprehensive income (loss), net of tax
Other comprehensive income (loss)		8,115	(29,385)	5,449	(19,924)
Less: reclassification adjustment for (gains) losses included in net income, net of tax		(27)	(199)	(97)	1,469
Balance		1,479,412	1,739,940	1,479,412	1,739,940
ASU 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Less: reclassification adjustment for (gains) losses included in net income, net of tax	[1]				(3,125)
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance				(12,523)	15,919
Other comprehensive income (loss) before reclassifications, net of tax				983	(18,781)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax
Other comprehensive income (loss)				983	(18,781)
Balance		(11,540)	(2,862)	(11,540)	(2,862)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance				(1,845)	1,362
Other comprehensive income (loss) before reclassifications, net of tax				4,637	(2,489)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax				(97)	1,469
Other comprehensive income (loss)				4,540	(1,020)
Reclassification of tax effects resulting from the Tax Reform Act, net of tax	[2]				691
Less: reclassification adjustment for (gains) losses included in net income, net of tax	[1]				(3,125)
Balance		2,695	(2,092)	2,695	(2,092)
Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance				1,328	1,495
Other comprehensive income (loss) before reclassifications, net of tax
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(37)	(61)	(74)	(123)
Other comprehensive income (loss)				(74)	(123)
Reclassification of tax effects resulting from the Tax Reform Act, net of tax	[2]				78
Balance		1,254	1,450	1,254	1,450
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(15,706)	25,881	(13,040)	18,776
Other comprehensive income (loss) before reclassifications, net of tax				5,620	(21,270)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(64)	(260)	(171)	(769)
Other comprehensive income (loss)		8,115	(29,385)	5,449	(19,924)
Reclassification of tax effects resulting from the Tax Reform Act, net of tax	[2]				769
Less: reclassification adjustment for (gains) losses included in net income, net of tax		27	199	97	(1,469)
Balance		$ (7,591)	$ (3,504)	$ (7,591)	$ (3,504)
[1]	In the six months ended July 1, 2018, Teradyne adopted the ASU 2016-01, “Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.”
[2]	In the six months ended July 1, 2018, Teradyne early adopted the ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” As a result, the stranded tax effects resulting from the Tax Reform Act enacted in December 2017 were reclassified from accumulated other comprehensive income to retained earnings.

Changes in Accumulated Other _2

Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss), tax	$ (17)	$ (86)	$ (47)	$ (24)
Reclassification of unrealized gains on equity securities, net of tax	(6)	(68)	(26)	11
Foreign currency translation adjustments, tax	0	0	0	0	$ 0	$ 0
Unrealized (losses) gains on marketable securities, tax	709	(511)	709	(511)	(521)	1,815
Retirement plans prior service benefit, tax	(1,102)	(1,045)	(1,102)	(1,045)	$ (1,081)	$ (932)
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax			0	0
Amounts reclassified from accumulated other comprehensive income (loss), tax			0	0
Other comprehensive income (loss), tax			0	0
Reclassification of income tax effects from the Tax Reform Act, net of tax				0
Unrealized (Losses) Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax			1,256	(774)
Amounts reclassified from accumulated other comprehensive income (loss), tax	(6)	(68)	26	11
Other comprehensive income (loss), tax			1,230	(733)
Reclassification of income tax effects from the Tax Reform Act, net of tax				(691)
Reclassification of unrealized gains on equity securities, net of tax				(902)
Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax			0	0
Amounts reclassified from accumulated other comprehensive income (loss), tax	$ (11)	$ (18)	(21)	(35)
Other comprehensive income (loss), tax			$ (21)	(35)
Reclassification of income tax effects from the Tax Reform Act, net of tax				(78)
Reclassification of unrealized gains on equity securities, net of tax				$ 0

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	$ 37	$ 61	$ 74	123
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	$ 64	$ 260	$ 171	$ 769

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 17	$ 86	$ 47	$ 24
Unrealized (Losses) Gains on Marketable Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	6	68	(26)	(11)
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 11	$ 18	$ 21	$ 35

Goodwill and Acquired Intangi_3

Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Goodwill and Intangible Assets Disclosure [Line Items]
Acquired intangible assets amortization	$ 10,083	$ 9,793	$ 20,717	$ 17,491

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Jun. 30, 2019
Goodwill [Line Items]
Goodwill acquisition	$ 1,428
Foreign currency translation adjustment	658
Goodwill	1,144,416	$ 1,146,502
Accumulated impairment losses	(762,566)	(762,566)
Goodwill	381,850	383,936
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	626
Goodwill	363,358	363,984
Accumulated impairment losses	0	0
Goodwill	363,358	363,984
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)
Goodwill	7,976	7,976
Semiconductor Test
Goodwill [Line Items]
Goodwill acquisition	1,428
Foreign currency translation adjustment	32
Goodwill	260,540	262,000
Accumulated impairment losses	(260,540)	(260,540)
Goodwill		1,460
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)
Goodwill	$ 10,516	$ 10,516

Schedule of Amortizable Intangi

Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2019		Dec. 31, 2018
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 502,181	[1],[2]	$ 498,231
Accumulated Amortization	(387,578)	[1]	(367,531)
Foreign Currency Translation Adjustment	(5,109)		(5,218)
Net Carrying Amount	109,494		125,482
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	337,198	[1],[2]	336,308
Accumulated Amortization	(265,951)	[1]	(252,080)
Foreign Currency Translation Adjustment	(4,035)		(4,079)
Net Carrying Amount	67,212		80,149
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	100,313	[1],[2]	97,153
Accumulated Amortization	(87,496)	[1]	(83,448)
Foreign Currency Translation Adjustment	(285)		(340)
Net Carrying Amount	12,532		13,365
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount	64,670	[1],[2]	64,420
Accumulated Amortization	(34,131)	[1]	(31,653)
Foreign Currency Translation Adjustment	(789)		(799)
Net Carrying Amount	$ 29,750		31,968
Non-compete Agreements
Finite-Lived Intangible Assets
Gross Carrying Amount			320
Accumulated Amortization			(320)
Backlog
Finite-Lived Intangible Assets
Gross Carrying Amount			30
Accumulated Amortization			$ (30)
[1]	$0.7 million of amortizable intangible assets became fully amortized and have been eliminated from the gross carrying amount and accumulated amortization.
[2]	Includes $4.6 million of intangible assets from Lemsys acquisition.

Schedule of Amortizable Intan_2

Schedule of Amortizable Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Finite-Lived Intangible Assets
Intangible Assets Fully Amortised	$ 10,083	$ 9,793	$ 20,717	$ 17,491
Lemsys [Member]
Finite-Lived Intangible Assets
Intangible assets acquired			$ 4,600

Schedule of Estimated Intangibl

Schedule of Estimated Intangible Asset Amortization Expense (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Finite-Lived Intangible Assets
2019 (remainder)	$ 18,745
2020	25,037
2021	14,778
2022	13,885
2023	13,410
Thereafter	$ 23,639

Computation of Basic and Dilute

Computation of Basic and Diluted Net (Loss) Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019		Jul. 01, 2018
Net Income Loss Per Common Share
Net income for basic and diluted net income per share		$ 97,397	$ 101,037	$ 206,535		$ 188,010
Weighted average common shares-basic		171,241	190,730	172,387		192,992
Incremental shares from assumed conversion of convertible notes	[1]	4,364	2,643	3,275		3,520
Convertible note hedge warrant shares		1,778		889	[2]	915	[2]
Employee stock purchase plan		22	43	16		28
Dilutive potential common shares		7,349	4,179	5,394		6,205
Weighted average common shares-diluted		178,590	194,909	177,781		199,197
Net income per common share-basic		$ 0.57	$ 0.53	$ 1.20		$ 0.97
Net income per common share-diluted		$ 0.55	$ 0.52	$ 1.16		$ 0.94
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		1,002	1,219	1,012		1,444
Stock Options
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		183	274	202		298
[1]	Incremental shares from 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 $31.70, multiplied by 14.5 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 $39.78, multiplied by 14.5 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.

Computation of Basic and Dilu_2

Computation of Basic and Diluted Net (Loss) Income Per Common Share (Parenthetical) (Detail) shares in Millions	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Convertible Notes
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 31.70
Shares that would be issued upon conversion | shares	14.5
Convertible Notes Hedge Warrant
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 39.78
Shares that would be issued upon conversion | shares	14.5

Net Income Per Common Share - A

Net Income Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Restricted Stock Units (RSUs) [Member]
Net Income Loss Per Common Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.2	0.6	0.4	0.5

Restructuring and Other - Addit

Restructuring and Other - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Restructuring Cost and Reserve
Contingent consideration adjustment	$ 11,700	$ 3,500	$ (8,701)	$ (8,468)
Acquisition related costs	500	2,500	1,800	3,300
Semiconductor Test
Restructuring Cost and Reserve
Severance benefit and charges	$ 800	$ 2,400	$ 1,600
Semiconductor Test, Industrial Automation and Corporate
Restructuring Cost and Reserve
Severance benefit and charges				$ 6,300

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
United States Plans
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 1.3
U.S. Supplemental Executive Defined Benefit Pension Plan
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 0.4

Schedule of Net Periodic Pensio

Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Defined Benefit Plan Disclosure
Net actuarial (gain) loss			$ 448	$ (71)
UNITED STATES
Defined Benefit Plan Disclosure
Service cost	$ 399	$ 545	804	1,116
Interest cost	1,799	2,430	3,595	5,427
Expected return on plan assets	(1,510)	(2,550)	(3,021)	(5,919)
Amortization of prior service cost		14		29
Net actuarial (gain) loss	252	(189)	252	(189)
Settlement loss		78		78
Total net periodic pension cost	940	328	1,630	542
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	192	200	381	426
Interest cost	176	175	349	372
Expected return on plan assets	(7)	(5)	(14)	(10)
Total net periodic pension cost	361	370	716	788
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	11	10	20	19
Interest cost	88	48	173	98
Amortization of prior service cost	(48)	(93)	(95)	(187)
Net actuarial (gain) loss	196	40	196	40
Special termination benefits		1,192		2,818
Total net periodic pension cost	$ 247	$ 1,197	$ 294	$ 2,788

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Jun. 30, 2019USD ($)
Purchase Commitment, Excluding Long-term Commitment
Aggregate purchase commitments	$ 306.9
Purchase commitments less than one year	$ 300.7

Schedule of Reconciliation of E

Schedule of Reconciliation of Effective Tax Rate (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Income Tax Disclosure [Line Items]
US statutory federal tax rate	21.00%	21.00%	21.00%	21.00%
Discrete expense related to U.S. transition tax	11.20%	0.00%	6.50%	0.00%
International provisions of the U.S. Tax Cuts and Jobs Act of 2017	0.80%	(1.40%)	0.80%	(1.40%)
Discrete benefit related to equity compensation	(0.50%)	(0.10%)	(2.00%)	(3.50%)
Foreign taxes	(4.90%)	(3.40%)	(4.90%)	(3.40%)
Tax credits	(2.50%)	(2.10%)	(2.50%)	(2.10%)
Discrete benefit related to release of reserves for uncertain tax positions	(0.10%)	0.00%	(12.90%)	0.00%
Other, net	0.80%	1.80%	2.30%	2.30%
Effective tax rate	25.80%	15.80%	8.30%	12.90%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Dec. 31, 2018
Income Taxes [Line Items]
Tax savings due to the tax holiday	$ 7	$ 4.8
Tax savings due to the tax holiday, per share	$ 0.04	$ 0.02
Reduction in un recognized tax benefits	$ 22.4
Accrued interest and penalties	0.4		$ 0.3
Interest and penalties related to income tax, expense (benefit)	0.1	$ 0.1
Uncertain tax positions	13.4		$ 43.4
Net decrease in uncertain tax positions	30
Minimum [Member]
Income Taxes [Line Items]
Potential tax reserve	5
Maximum [Member]
Income Taxes [Line Items]
Potential tax reserve	11
Research Tax Credit Carryforward [Member]
Income Taxes [Line Items]
Net decrease in uncertain tax positions	$ 7.3

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019Segment
Segment Reporting Information [Line Items]
Number of Operating Segments	4

Schedule of Segment Information

Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2019		Jul. 01, 2018		Jun. 30, 2019		Jul. 01, 2018		Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues		$ 564,178		$ 526,929		$ 1,058,277		$ 1,014,396
Income (loss) before income taxes	[1],[2]	131,177		120,012		225,156		215,831
Total assets		2,671,514	[3]	2,931,720	[3]	2,671,514	[3]	2,931,720	[3]	$ 2,706,606
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		374,898		360,088		715,751		733,416
Income (loss) before income taxes	[1],[2]	91,355		91,159		174,404		179,238
Total assets	[3]	745,073		765,484		745,073		765,484
System Test
Segment Reporting Information [Line Items]
Revenues		73,407		69,682		131,627		112,702
Income (loss) before income taxes	[1],[2]	23,535		20,352		38,875		26,240
Total assets	[3]	123,460		107,199		123,460		107,199
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		74,726		62,057		140,862		110,891
Income (loss) before income taxes	[1],[2]	(3,730)		(2,922)		(9,025)		(2,138)
Total assets	[3]	601,676		597,293		601,676		597,293
Wireless Test
Segment Reporting Information [Line Items]
Revenues		41,236		35,212		70,277		57,719
Income (loss) before income taxes	[1],[2]	10,930		10,308		14,558		10,772
Total assets	[3]	93,232		77,638		93,232		77,638
Corporate And Others [Member]
Segment Reporting Information [Line Items]
Revenues		(89)		(110)		(240)		(332)
Income (loss) before income taxes	[1],[2]	9,087		1,115		6,344		1,719
Total assets	[3]	$ 1,108,073		$ 1,384,106		$ 1,108,073		$ 1,384,106
[1]	Included in Corporate and Other are: contingent consideration adjustments, severance charges, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations, acquisition related charges, and pension and postretirement plans actuarial losses.
[2]	Included in the income (loss) before income taxes for each of the segments are charges and credits related to restructuring and other and inventory charges.
[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		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Segment Reporting Information [Line Items]
Acquisition related costs	$ 500	$ 2,500	$ 1,800	$ 3,300
Restructuring and other-employee severance	(10,404)	2,389	(5,292)	2,076
Contingent consideration adjustment	11,700	3,500	(8,701)	(8,468)
Universal Robots (UR)
Segment Reporting Information [Line Items]
Contingent consideration adjustment		24,600
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	2,278	1,613	3,452	3,779
Semiconductor Test | Severance And Benefits
Segment Reporting Information [Line Items]
Restructuring and other-employee severance	357	2,179	924	5,940
System Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	295	256	763	576
Industrial Automation
Segment Reporting Information [Line Items]
Acquisition related costs	434		1,695
Cost of revenues-inventory charge			416
Restructuring and other-employee severance		218		338
Industrial Automation | Severance And Benefits
Segment Reporting Information [Line Items]
Restructuring and other-employee severance	202		297
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	829	627	1,168	1,463
Corporate And Eliminations | Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs		2,544		3,318
Corporate And Eliminations | Universal Robots (UR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment		$ (3,500)		$ (8,468)
Corporate And Eliminations | Mobile Industrial Robots (MiR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment	$ (11,671)		$ (8,668)

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 31, 2019	Jan. 31, 2019	Jan. 31, 2018
Cumulative repurchases, value	$ 89,154	$ 226,520	$ 240,624	$ 367,191
Common stock average price			$ 38.20	$ 40.82
Dividends Payable, Amount Per Share						$ 0.09	$ 0.09
Dividend payment	15,400	17,100	$ 31,019	$ 34,682
Common Stock [Member]
Cumulative repurchases, value	$ 252	$ 738	$ 809	$ 1,106
Cumulative repurchases, shares	(2,016)	(5,900)	(6,471)	(8,839)
Share Repurchase Program [Member]
Stock repurchase program, authorized amount	$ 28,100		$ 28,100
Cumulative repurchases, value			$ 1,100,000
Common stock average price			$ 38.09
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	1,500,000		1,500,000
Maximum [Member]
Stock repurchase program, authorized amount							$ 1,500,000
Forecast [Member]
Cumulative repurchases, value					$ 500,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	Jul. 17, 2019	Sep. 30, 2019
Subsequent Event [Line Items]
Stock Based Compensation Relating To Retirement Agreement		$ 2.5
Subsequent Event | CEO Gregory Beecher [Member]
Subsequent Event [Line Items]
Date Of Retirement	Jul. 17, 2019
Subsequent Event | CEO Gregory Beecher [Member] | Service Based Restricted Stock Units
Subsequent Event [Line Items]
Description Of The Vesting Agreement	unvested time-based restricted stock units and stock options granted prior to 2019 will continue to vest in accordance with their terms; unvested time-based restricted stock units and stock options granted in 2019 prior to the Retirement Date will continue to vest during the Non-Competition Period in a pro-rated amount based on the number of days that Mr. Beecher was employed during 2019
Subsequent Event | CEO Gregory Beecher [Member] | Performance Shares
Subsequent Event [Line Items]
Description Of The Vesting Agreement	unvested, performance-based restricted stock units awarded prior to 2019 will continue to vest in accordance with their terms; unvested, performance-based restricted stock units awarded in 2019 will vest on the date the amount of shares underlying the performance-based restricted stock units are determined in a pro-rated amount of shares based on the number of days that Mr. Beecher was employed during the 365 calendar day period

Accounting Policies - Additiona

Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Feb. 28, 2016
Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Liability	$ 64,501	$ 54,300	$ 54,300
Operating Lease, Right-of-Use Asset	$ 56,315	$ 50,100	$ 50,100