Teradyne (TER) 10-Q 4 May 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 29, 2020	Apr. 27, 2020
Cover [Abstract]
Amendment Flag	false
Document Type	10-Q
Document Fiscal Year Focus	2020
Entity Central Index Key	0000097210
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Document Period End Date	Mar. 29, 2020
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		165,768,292

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 593,494	$ 773,924
Marketable securities	211,001	137,303
Accounts receivable, less allowance for doubtful accounts of $1,813 and $1,736 at March 29, 2020 and December 31, 2019, respectively	487,365	362,368
Inventories, net	182,978	196,691
Prepayments and other current assets	227,740	188,598
Total current assets	1,702,578	1,658,884
Property, plant and equipment, net	332,241	320,216
Operating lease right-of-use assets, net	58,808	57,539
Marketable securities	100,513	104,490
Deferred tax assets	74,493	75,185
Retirement plans assets	18,229	18,457
Other assets	9,272	10,332
Acquired intangible assets, net	114,321	125,480
Goodwill	409,933	416,431
Total assets	2,820,388	2,787,014
Current liabilities:
Accounts payable	129,633	126,617
Accrued employees' compensation and withholdings	119,226	163,883
Deferred revenue and customer advances	98,815	104,876
Other accrued liabilities	87,274	70,871
Operating lease liabilities	19,591	19,476
Contingent consideration	662	9,106
Income taxes payable	58,760	44,200
Total current liabilities	513,961	539,029
Retirement plans liabilities	125,970	134,471
Long-term deferred revenue and customer advances	50,791	45,974
Long-term other accrued liabilities	19,941	19,535
Long-term contingent consideration	19,810	30,599
Deferred tax liabilities	11,628	14,070
Long-term operating lease liabilities	46,328	45,849
Long-term incomes taxes payable	82,820	82,642
Debt	398,466	394,687
Total liabilities	1,269,715	1,306,856
Commitments and contingencies (See Note Q)
SHAREHOLDERS' EQUITY
Common stock, $0.125 par value, 1,000,000 shares authorized, 165,938 and 166,410 shares issued and outstanding at March 29, 2020 and December 31, 2019, respectively	20,742	20,801
Additional paid-in capital	1,721,367	1,720,129
Accumulated other comprehensive loss	(27,113)	(18,854)
Accumulated deficit	(164,323)	(241,918)
Total shareholders' equity	1,550,673	1,480,158
Total liabilities and shareholders' equity	$ 2,820,388	$ 2,787,014

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Accounts receivable, less allowance for doubtful accounts	$ 1,813	$ 1,736
Common stock, par value	$ 0.125	$ 0.125
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	165,938,000	166,410,000
Common stock, shares outstanding	165,938,000	166,410,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
Revenues:
Total revenues	[1]	$ 704,355	$ 494,099
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		298,805	206,464
Gross profit		405,550	287,635
Operating expenses:
Selling and administrative		111,388	102,013
Engineering and development		85,159	76,791
Acquired intangible assets amortization		9,891	10,634
Restructuring and other		(7,606)	5,112
Total operating expenses		198,832	194,550
Income from operations		206,718	93,085
Non-operating (income) expense:
Interest income		(2,751)	(4,989)
Interest expense		5,551	5,520
Other (income) expense, net		6,849	(1,425)
Income before income taxes		197,069	93,979
Income tax provision (benefit)		20,878	(15,159)
Net income		$ 176,191	$ 109,138
Net income per common share:
Basic		$ 1.06	$ 0.63
Diluted		$ 0.97	$ 0.62
Weighted average common shares—basic		166,589	173,532
Weighted average common shares—diluted		180,736	176,972
Cash dividend declared per common share		$ 0.10	$ 0.09
Product [Member]
Revenues:
Total revenues		$ 610,906	$ 393,442
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		259,996	165,368
Service [Member]
Revenues:
Total revenues		93,449	100,657
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		$ 38,809	$ 41,096
[1]	Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Net income	$ 176,191	$ 109,138
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax of $0, $0, respectively	(8,779)	(4,659)
Available-for-sale marketable securities:
Unrealized gains on debt securities arising during period, net of tax of $187, $577, respectively	1,037	2,100
Less: Reclassification adjustment for gains included in net income, net of tax of $(145), $(20), respectively	(515)	(70)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	522	2,030
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 $0, $(11), respectively	(2)	(37)
Other comprehensive loss	(8,259)	(2,666)
Comprehensive income	$ 167,932	$ 106,472

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Foreign currency translation adjustments, tax	$ 0	$ 0
Unrealized gains (losses) on marketable securities arising during period, net of tax	187	577
Reclassification adjustment for (gains) losses included in net income, net of tax	(145)	(20)
Amortization of prior service benefit included in net periodic pension and post-retirement benefit, net of tax	$ 0	$ (11)

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 (Loss) Income	Accumulated Deficit
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	(49)	$ 161	(210)
Net issuance of common stock under stock-based plans (in shares)		1,287
Stock-based compensation expense	8,562		8,562
Repurchase of common stock	$ (151,470)	$ (557)			(150,913)
Repurchase of common stock (in shares)	4,500	(4,456)
Cash dividends	$ (15,641)				(15,641)
Net income	109,138				109,138
Other comprehensive loss	(2,666)			(2,666)
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
Balance at Dec. 31, 2019	1,480,158	$ 20,801	1,720,129	(18,854)	(241,918)
Balance, Shares at Dec. 31, 2019		166,410
Net issuance of common stock under stock-based plans	(9,936)	$ 109	(10,045)
Net issuance of common stock under stock-based plans (in shares)		872
Stock-based compensation expense	11,283		11,283
Repurchase of common stock	$ (82,065)	$ (168)			(81,897)
Repurchase of common stock (in shares)	1,300	(1,344)
Cash dividends	$ (16,699)				(16,699)
Net income	176,191				176,191
Other comprehensive loss	(8,259)			(8,259)
Balance at Mar. 29, 2020	$ 1,550,673	$ 20,742	$ 1,721,367	$ (27,113)	$ (164,323)
Balance, Shares at Mar. 29, 2020		165,938

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Common Stock, Dividends, Per Share, Cash Paid	$ 0.10	$ 0.09

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 176,191	$ 109,138
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Depreciation	18,489	16,651
Amortization	13,391	12,942
Stock-based compensation	10,460	9,474
Provision for excess and obsolete inventory	4,057	2,397
Deferred taxes	(1,825)	1,206
Contingent consideration adjustment	(10,020)	2,970
Losses (gains) on investments	4,657	(2,828)
Other	503	219
Changes in operating assets and liabilities, net of businesses acquired:
Accounts receivable	(126,779)	(41,706)
Inventories	15,818	(2,917)
Prepayments and other assets	(39,620)	(18,648)
Accounts payable and other liabilities	(35,323)	(53,323)
Deferred revenue and customer advances	(913)	6,455
Retirement plans contributions	(1,262)	(1,210)
Income taxes	15,278	(22,804)
Net cash provided by operating activities	43,102	18,016
Cash flows from investing activities:
Purchases of property, plant and equipment	(36,700)	(25,711)
Purchases of marketable securities	(187,119)	(375,184)
Proceeds from maturities of marketable securities	98,457	141,201
Proceeds from sales of marketable securities	15,005	5,440
Acquisition of businesses, net of cash acquired	149	(6,970)
Proceeds from life insurance		273
Net cash used for investing activities	(110,208)	(260,951)
Cash flows from financing activities:
Issuance of common stock under stock purchase and stock option plans	12,752	14,268
Repurchase of common stock	(79,039)	(156,468)
Dividend payments	(16,686)	(15,627)
Payments related to net settlement of employee stock compensation awards	(22,070)	(14,318)
Payments of contingent consideration	(8,852)	(27,615)
Net cash used for financing activities	(113,895)	(199,760)
Effects of exchange rate changes on cash and cash equivalents	571	(329)
Decrease in cash and cash equivalents	(180,430)	(443,024)
Cash and cash equivalents at beginning of period	773,924	926,752
Cash and cash equivalents at end of period	$ 593,494	$ 483,728

The Company

The Company	3 Months Ended
	Mar. 29, 2020
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; • 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”); • industrial automation (“Industrial Automation”) products; and • wireless test (“Wireless Test”) systems.

Accounting Policies

Accounting Policies	3 Months Ended
	Mar. 29, 2020
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, 2019 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. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and our markets. Teradyne is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of May 4 Goodwill On January 26, 2017, the Financial Accounting Standards Board (“FASB”) issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment.” 2017-04 2017-04, one-step Credit Losses In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” This standard introduced the expected credit losses methodology for the measurement of credit losses on financial assets that are not measured at fair value through net income and replaces the “incurred loss” model with an “expected credit loss” model that requires consideration of a broader range of information to estimate expected credit losses over the lifetime of the asset. Teradyne adopted this standard on January 1, 2020 on a modified retrospective basis. The adoption of ASU 2016-13 did not have a material impact on the consolidated statement of operations, balance sheets, cash flows, or earnings per share.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 29, 2020
Acquisitions	C. ACQUISITIONS AutoGuide LLC On November 13, 2019, Teradyne acquired 100% of the membership interests of AutoGuide, LLC (“AutoGuide”), a maker of high-payload autonomous mobile robots (“AMRs”), based in Chelmsford, MA, an emerging and fast growing segment of the global forklift market. The total purchase price was approximately $81.6 million, which included cash paid of approximately $57.6 million and $24.0 million in fair value of contingent consideration payable upon achievement of certain performance targets, extending potentially through 2022. At March 29, 2020, the maximum contingent consideration that could be paid is $106.9 million. The contingent consideration is payable upon achievement of certain thresholds and targets for revenue and earnings before interest and taxes for periods from January 1, 2019 to December 31, 2020, January 1, 2019 to December 31, 2021, and January 1, 2019 to December 31, 2022. 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 AutoGuide 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. AutoGuide’s AMRs are used for material transport of payloads up to 4,500 kg in manufacturing, warehouse and logistics applications. These products complement MiR’s lower payload products and expand the Industrial Automation segment, which is a key component of Teradyne’s growth strategy. The allocation of the total purchase price to AutoGuide’s net tangible assets 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 assets in the amount of $41.2 million was allocated to goodwill, which is deductible for tax purposes. AutoGuide’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 $ 41,223 Intangible assets 37,660 Tangible assets acquired and liabilities assumed: Other current assets 3,661 Non-current assets 1,227 Accounts payable and current liabilities (1,223 ) Long-term other liabilities (949 ) Total purchase price $ 81,599 Teradyne estimated the fair value of intangible assets using the income approach. Forecasted revenues is the key assumption for estimating the fair value. . 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 $ 24,590 6.0 Customer relationships 7,360 6.0 Trademarks and tradenames 5,450 7.0 Backlog 260 0.3 Total intangible assets $ 37,660 6.1 The following unaudited pro forma information gives effect to the acquisition of AutoGuide 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 Ended March 31, 2019 (in thousands, except Revenue s $ 495,599 Net income $ 107,289 Net income per common share: Basic $ 0.62 Diluted $ 0.61 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 and wind power, 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

Revenue

Revenue	3 Months Ended
	Mar. 29, 2020
Revenue from Contract with Customer [Abstract]
Revenue	D. REVENUE Disaggregation of Revenue The following table provides information about disaggregated revenue by timing of revenue recognition, primary geographical market, and major product lines. Semiconductor Test Industrial Automation Wireless Test Corporate and Other Total System on Memory System Universal Mobile AutoGuide (in thousands) For the Three Months Ended March 29, 2020 (1) Timing of Revenue Recognition Point in Time $ 348,044 $ 79,398 $ 100,712 $ 47,502 $ 9,097 $ 1,124 $ 41,056 $ — $ 626,933 Over Time 52,095 4,952 15,364 2,195 41 346 2,429 — 77,422 Total $ 400,139 $ 84,350 $ 116,076 $ 49,697 $ 9,138 $ 1,470 $ 43,485 $ — $ 704,355 Geographical Market Asia Pacific $ 362,732 $ 76,110 $ 80,017 $ 10,917 $ 1,593 $ — $ 37,805 $ — $ 569,174 Americas 17,386 6,896 28,291 14,743 3,465 1,470 4,688 — 76,939 Europe, Middle East and Africa 20,021 1,344 7,768 24,037 4,080 — 992 — 58,242 Total $ 400,139 $ 84,350 $ 116,076 $ 49,697 $ 9,138 $ 1,470 $ 43,485 $ — $ 704,355 For the Three Months Ended March 31, 2019 (1) Timing of Revenue Recognition Point in Time $ 238,755 $ 43,775 $ 45,237 $ 55,379 $ 9,106 $ — $ 27,454 $ (151 ) $ 419,555 Over Time 54,051 4,272 12,983 1,651 — — 1,587 — 74,544 Total $ 292,806 $ 48,047 $ 58,220 $ 57,030 $ 9,106 $ — $ 29,041 $ (151 ) $ 494,099 Geographical Market Asia Pacific $ 260,326 $ 38,851 $ 24,285 $ 14,618 $ 1,727 $ — $ 26,019 $ — $ 365,826 Americas 16,167 8,763 26,809 15,803 3,539 — 2,241 (151 ) 73,171 Europe, Middle East and Africa 16,313 433 7,126 26,609 3,840 — 781 — 55,102 Total $ 292,806 $ 48,047 $ 58,220 $ 57,030 $ 9,106 $ — $ 29,041 $ (151 ) $ 494,099 (1) Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “ Revenue from Contracts with Customers.” Contract Balances For , Teradyne recognized $ million and $ million, respectively, that was previously included within the deferred revenue and customer advances balances. This revenue primarily relates to undelivered hardware, extended warranties, training, application support, and post contract support. Each of these represents a distinct performance obligation. Teradyne expects to recognize % of the remaining performance obligation in the next 12 months, % in 1 3 years, and the remainder thereafter. Accounts Receivable Teradyne sells certain trade accounts receivables on a non-recourse

Inventories

Inventories	3 Months Ended
	Mar. 29, 2020
Inventories	E Inventories, net consisted of the following at March 29, 2020 and December 31, 2019: March 29, December 31, 2020 2019 (in thousands) Raw material $ 102,109 $ 118,595 Work-in-process 39,848 32,695 Finished goods 41,021 45,401 $ 182,978 $ 196,691 Inventory reserves at March 29, 2020 and December 31, 2019 were $105.3 million and $103.6 million, respectively.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 29, 2020
Financial Instruments	F 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 and equity and debt mutual funds are classified During the three months ended March 29, 2020 and March 31, 2019, there were no transfers in or out of Level 1, Level 2, or Level 3 financial instruments. Realized gains recorded in the three months ended March 29, 2020 and March 31, 2019 were $1.4 million and $0.1 million, respectively. Realized losses recorded in the three months ended March 29, 2020 and March 31, 2019 were $0.1 million. Realized gains and losses are included in other (income) expense, net. Unrealized losses on equity securities recorded in the three months ended March 29, 2020 were million. Unrealized gains on equity securities recorded in the three months ended March 31, 2019 were Unrealized gains and losses on equity securities are included in other (income) expense, net. 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 March 29, 2020 and December 31, 2019. March 29, 2020 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 $ 270,460 $ — $ — $ 270,460 Cash equivalents 244,176 78,858 — 323,034 Available-for-sale Commercial paper — 101,947 — 101,947 U.S. Treasury securities — 85,632 — 85,632 Corporate debt securities — 67,467 — 67,467 Certificates of deposit and time deposits — 25,776 — 25,776 Debt mutual funds 5,237 — — 5,237 U.S. government agency securities — 4,402 — 4,402 Non-U.S. — 589 — 589 Equity securities: Mutual funds 20,464 — — 20,464 $ 540,337 $ 364,671 $ — $ 905,008 Derivative assets — 344 — 344 Total $ 540,337 $ 365,015 $ — $ 905,352 Liabilities Contingent consideration $ — $ — $ 20,472 $ 20,472 Derivative liabilities — 254 — 254 Total $ — $ 254 $ 20,472 $ 20,726 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 514,636 $ 78,858 $ — $ 593,494 Marketable securities — 211,001 — 211,001 Long-term marketable securities 25,701 74,812 — 100,513 Prepayments and other current assets — 344 — 344 Total $ 540,337 $ 365,015 $ — $ 905,352 Liabilities Other current liabilities $ — $ 254 $ — $ 254 Contingent consideration — — 662 662 Long-term contingent consideration — — 19,810 19,810 Total $ — $ 254 $ 20,472 $ 20,726 December 31, 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 $ 311,975 $ — $ — 311,975 Cash equivalents 410,285 51,664 — 461,949 Available-for-sale Corporate debt securities — 97,307 — 97,307 Commercial paper — 54,149 — 54,149 U.S. Treasury securities — 42,382 — 42,382 U.S. government agency securities — 9,952 — 9,952 Debt mutual funds 6,888 — — 6,888 Certificates of deposit and time deposits — 4,751 — 4,751 Non-U.S. — 592 — 592 Equity securities: Equity mutual funds 25,772 — — 25,772 $ 754,920 $ 260,797 $ — $ 1,015,717 Derivative assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Contingent consideration $ — $ — $ 39,705 $ 39,705 Derivative liabilities — 203 — 203 Total $ — $ 203 $ 39,705 $ 39,908 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 722,260 $ 51,664 $ — $ 773,924 Marketable securities — 137,303 — 137,303 Long-term marketable securities 32,660 71,830 — 104,490 Prepayments and other current assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Other accrued liabilities $ — $ 203 $ — $ 203 Contingent consideration — — 9,106 9,106 Long-term contingent consideration — — 30,599 30,599 Total $ — $ 203 $ 39,705 $ 39,908 Changes in the fair value of Level 3 contingent consideration for the three months ended March 29, 2020 and March 31, 2019 were as follows: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 39,705 $ 70,543 Foreign currency impact (361 ) (610 ) Payments (a)(b) (8,852 ) (34,590 ) Fair value adjustment (c)(d) (10,020 ) 2,970 Balance at end of period $ 20,472 $ 38,313 (a) In the three months ended March 29, 2020, Teradyne paid $8.9 million of contingent consideration for the earn-out (b) In the three months ended March 31, 2019, Teradyne paid $30.8 million and $3.8 million of contingent consideration for the earn-outs in connection with the acquisitions of MiR and Universal Robots A/S (“Universal Robots”), respectively. (c) In the three months ended March 29, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisitions of MiR and AutoGuide decreased by $2.9 million and $7.1 million, respectively, due to lower forecasted results. (d) In the three months ended March 31, 2019, the fair value of contingent consideration for the earn-out The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instruments: Liability March 29, 2020 Fair Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent consideration (AutoGuide) $ 19,810 Monte Carlo Simulation Revenue volatility 14.0 % Discount Rate 4.4 % Contingent consideration (MiR) $ 662 Monte Carlo Simulation Revenue volatility 16.0 % Discount Rate 2.2 % As of March 29, 2020, the significant unobservable inputs used in the Monte Carlo simulation to fair value the AutoGuide and 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 March 29, 2020, the maximum amount of contingent consideration that could be paid in connection with the acquisition of AutoGuide is $106.9 million. The earn-out As of March 29, 2020, the maximum amount of contingent consideration that could be paid in connection with the acquisition of MiR is $61.4 million. The remaining earn-out The carrying amounts and fair values of Teradyne’s financial instruments at March 29, 2020 and December 31, 2019 were as follows: March 29, 2020 December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 593,494 $ 593,494 $ 773,924 $ 773,924 Marketable securities 311,514 311,514 241,793 241,793 Derivative assets 344 344 528 528 Liabilities Contingent consideration 20,472 20,472 39,705 39,705 Derivative liabilities 254 254 203 203 Convertible debt (1) 398,466 829,438 394,687 1,010,275 (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 March 29, 2020 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Commercial paper $ 101,915 $ 33 $ (1 ) $ 101,947 $ 1,296 U.S. Treasury securities 82,680 2,958 (6 ) 85,632 96 Corporate debt securities 65,696 2,951 (1,180 ) 67,467 40,891 Certificates of deposit and time deposits 25,769 7 — 25,776 — Debt mutual funds 5,089 148 — 5,237 — U.S. government agency securities 4,335 67 — 4,402 — Non-U.S. 589 — — 589 — $ 286,073 $ 6,164 $ (1,187 ) $ 291,050 $ 42,283 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 210,722 $ 430 $ (151 ) $ 211,001 $ 32,037 Long-term marketable securities 75,351 5,734 (1,036 ) 80,049 10,246 $ 286,073 $ 6,164 $ (1,187 ) $ 291,050 $ 42,283 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 137,144 $ 160 $ (1 ) $ 137,303 $ 2,922 Long-term marketable securities 74,452 4,527 (261 ) 78,718 21,077 $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999 As of March 29, 2020 and December 31, 2019, the fair market value of investments with unrealized losses less than one year totaled $42.3 million and $23.6 million, respectively. 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 March 29, 2020 and December 31, 2019 were not other than temporary. The contractual maturities of investments in available-for-sale March 29, 2020 Cost Fair Market Value (in thousands) Due within one year $ 210,722 $ 211,001 Due after 1 year through 5 years 18,933 19,465 Due after 5 years through 10 years 12,440 13,160 Due after 10 years 38,889 42,187 Total $ 280,984 $ 285,813 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 March 29, 2020 and December 31, 2019 was $132.1 million and $144.9 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 March 29, 2020 and December 31, 2019: Balance Sheet Location March 29, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 344 $ 528 Foreign exchange contracts Other current liabilities (254 ) (203 ) Total derivatives $ 90 $ 325 The following table summarizes the effect of derivative instruments recognized in the statement of operations for the three months ended March 29, 2020 and March 31, 2019: Location of Losses For the Three Months Ended Recognized in March 29, March 31, 2020 2019 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 4,011 $ 3,934 (1) The table does not reflect the corresponding gains and losses from the remeasurement of the (2) For the three months ended March 29, 2020 and March 31, 2019, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $2.0 See Note G

Debt

Debt	3 Months Ended
	Mar. 29, 2020
Debt	G Convertible Senior Notes On December 12, 2016, Teradyne completed a private offering of $460.0 million aggregate principal amount of 1.25% convertible senior unsecured notes (the “Notes”) due December 15, 2023 and received net proceeds, after issuance costs, of approximately $450.8 million, $33.0 million of which was used to pay the net cost of the convertible note hedge transactions and $50.1 million of which was used to repurchase 2.0 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 15, 2023, unless earlier repurchased or converted. The Notes bear interest from December 12, 2016 at a rate of 1.25% per year payable semiannually in arrears on June 15 and December 15 of each year. 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: (1) during any calendar quarter beginning after March 31, 2017 (and only during such calendar quarter), if the closing sale price of Teradyne’s common stock, for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than 130% of the conversion price on each applicable trading day; (2) 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 $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the closing sale price of the Teradyne’s common stock and the conversion rate on each such trading day; and (3) upon the occurrence of specified corporate events. On or after September 15, 2023 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 March 29, 2020, the conversion price was approximately $ per share of Teradyne’s common stock. The conversion rate is subject to adjustment under certain circumstances. As of May 4 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 $31.61. The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, approximately 14.6 million shares of Teradyne’s common stock. Separately and concurrent with the pricing of the Notes, entered into warrant transactions with the Option (the “Warrant Transactions”) in which it sold net-share-settled (or, at its election subject to certain conditions, cash-settled) warrants to the Option . The Warrant Transactions cover, subject to customary anti-dilution adjustments, approximately 14.6 million shares of common stock. As of March 29, 2020, the strike price of the warrants was approximately $ per share. The strike price is subject to adjustment under certain circumstances. The Warrant Transactions could have a dilutive effect to ’s common stock to the extent that the market price per share of ’s common stock, as measured under the terms of the Warrant Transactions, exceeds the applicable strike price of the warrants. 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 $33.0 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,” fixed-for-fixed Teradyne assessed whether the convertible note hedge should be classified as equity under ASC 815-40. 815-40 Teradyne analyzed the Warrant Transactions under ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” paid-in The provisions of ASC 470-20, Debt with Conversion and Other Options, 470-20 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 $7.2 million are being amortized to interest expense using the effective interest method over the seven-year term of the Notes. As of March 29, 2020, debt issuance costs were approximately $4.1 million. The below tables represent the key components of Teradyne’s convertible senior notes: March 29, December 31, (in thousands) Debt Principal $ 459,987 $ 460,000 Unamortized discount 61,521 65,313 Net Carrying amount of convertible debt $ 398,466 $ 394,687 For the Three Months Ended March 29, March 31, (in thousands) Contractual interest expense on the coupon $ 1,438 $ 1,438 Amortization of the discount component and debt issue fees recognized as interest expense 3,792 3,608 Total interest expense on the convertible debt $ 5,230 $ 5,046 As of March 29, 2020, the remaining unamortized discount was $61.5 million, which will be amortized over 3.7 years using the effective interest rate method. The carrying amount of the equity component was $100.8 million. As of March 29, 2020, the if-converted .

Prepayments

Prepayments	12 Months Ended
	Dec. 31, 2019
Prepayments	H Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: March 29, December 31, 2020 2019 (in thousands) Contract manufacturer and supplier prepayments $ 173,082 $ 143,392 Prepaid taxes 9,667 8,046 Prepaid maintenance and other services 10,828 8,503 Other prepayments 17,890 16,753 Total prepayments $ 211,467 $ 176,694

Deferred Revenue and Customer A

Deferred Revenue and Customer Advances	3 Months Ended
	Mar. 29, 2020
Deferred Revenue and Customer Advances	I 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: March 29, December 31, 2020 2019 (in thousands) Maintenance, se r $ 68,483 $ 63,815 Extended warranty 33,503 30,677 Customer advances, undelivered elements and other 47,620 56,358 Total deferred revenue and customer advances $ 149,606 $ 150,850

Product Warranty

Product Warranty	3 Months Ended
	Mar. 29, 2020
Product Warranty	J Teradyne generally provides a one-year For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 8,996 $ 7,909 Acquisition — 14 Accruals for warranties issued during the period 5,066 3,066 Accruals related to pre-existing 1,056 1,330 Settlements made during the period (4,147 ) (4,567 ) Balance at end of period $ 10,971 $ 7,752 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. For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 30,677 $ 27,422 Deferral of new extended warranty revenue 7,600 5,820 Recognition of extended warranty deferred revenue (4,774 ) (6,000 ) Balance at end of period $ 33,503 $ 27,242

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 29, 2020
Stock-Based Compensation	K Under Teradyne’s stock compensation plans, Teradyne grants service-based restricted stock units, performance-based restricted stock units and stock options, and employees are eligible to purchase Teradyne’s common stock through its Employee Stock Purchase Plan (“ESPP”). Service non-employee service Performance-based restricted stock units (“PRSUs”) granted to Teradyne’s executive officers may 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 0% to 200% of the target shares capped at four times the grant date value for grants prior to 2019. 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 executive officers meeting the retirement provisions prior to the grant date is recognized during the 365 days following 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. PRSUs granted to Teradyne’s executive officers may also have a performance metric based on three-year cumulative non-GAAP profit before interest and tax (“PBIT”) as a percent of ’s revenue. Non-GAAP PBIT is a financial measure equal to GAAP income from operations less restructuring and other, net; amortization of acquired intangible assets; acquisition and divestiture related charges or credits; pension actuarial gains and losses; non-cash convertible debt interest expense; and other non-recurring gains and charges. The final number of PBIT PRSUs that vest will vary based upon the level of performance achieved from % to % of the target shares. The PBIT PRSUs will vest upon the three-year anniversary of the grant date. Compensation expense is recognized on a straight-line basis over the shorter of the three-year service period or the period from the grant date to the date described in the retirement provisions below. Compensation expense for executive officers meeting the retirement provisions prior to the grant date is recognized during the 365 days following the 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 three 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. During the three months ended March 29, 2020 and March 31, 2019, Teradyne granted 0.4 million and 0.6 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $70.98 and $35.88, respectively. During the three months ended March 29, 2020 and March 31, 2019, Teradyne granted 0.1 million of PBIT PRSUs with a grant date fair value of $70.94 and $35.67, respectively. During the three months ended March 29, 2020 and March 31, 2019, Teradyne grante d million TSR PRSUs, with a grant date fair value of $ and $ , respectively. For the Three Months Ended March 29, March 31, 2020 2019 Risk-free interest rate 1.5 % 2.6 % Teradyne volatility-historical 34.9 % 31.8 % NYSE Composite Index volatility-historical 11.4 % 12.0 % Dividend yield 0.6 % 1.0 % Expected volatility was based on the historical volatility of Teradyne’s stock and the NYSE Composite Index for the 2020 and 2019 grant over the most recent three-year period. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.40 per share divided by Teradyne’s stock price on the grant date of $ for the 2020 grant and an estimated annual dividend amount of $ per share divided by Teradyne’s stock price on the grant date of $ for the 2019 grant. During the three months ended March 29, 2020 and March 31, 2019, Teradyne granted 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $ and $ , respectively. The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Three Months Ended March 29, March 31, 2020 2019 Expected life (years) 5.0 5.0 Risk-free interest rate 1.6 % 2.6 % Volatility-historical 31.6 % 30.1 % Dividend yield 0.6 % 1.0 % 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 $0.40 per share divided by Teradyne’s stock price on the grant date of $ for the 2020 grant and an estimated annual dividend amount of $0.36 per share divided by Teradyne’s stock price on the grant date of $ for the 2019 grant.

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income	3 Months Ended
	Mar. 29, 2020
Accumulated Other Comprehensive Income (Loss)	L. ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME Changes in accumulated other comprehensive (loss) income, 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) Three Months Ended March 29, 2020 Balance at December 31, 2019, net of tax of $0, $946, $(1,124) $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) Other comprehensive income (loss) before reclassifications, net of tax of $0, $187, $0 (8,779 ) 1,037 — (7,742 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(145), $0 — (515 ) (2 ) (517 ) Net current period other comprehensive income (loss), net of tax of $0, $42, $0 (8,779 ) 522 (2 ) (8,259 ) Balance at March 29, 2020, net of tax of $0, $988, $(1,124) $ (32,293 ) $ 4,002 $ 1,178 $ (27,113 ) Three Months Ended March 31 Balance at December 31, 2018, net of tax of $0, $(521), $(1,081) $ (12,523 ) $ (1,845 ) $ 1,328 $ (13,040 ) Other comprehensive income (loss) before reclassifications, net of tax of $0, $577, $0 (4,659 ) 2,100 — (2,559 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(20), $(11) — (70 ) (37 ) (107 ) Net current period other comprehensive income (loss), net of tax of $0, $557, $(11) (4,659 ) 2,030 (37 ) (2,666 ) Balance as March 31, 2019, net of tax of $0, $36, $(1,092) $ (17,182 ) $ 185 $ 1,291 $ (15,706 ) Reclassifications out of accumulated other comprehensive (loss) income to the statement of operations for the three months ended March 29, 2020 and March 31, 2019 were as follows: For the Three Months Ended Affected Line Item in the Statements of Operations March 29, March 31, 2020 2019 Details about Accumulated Other Comprehensive ( loss (in thousands) Available-for-sale Unrealized gains, net of tax of $145, $20 $ 515 $ 70 Interest income Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $0, $11 2 37 (a) Total reclassifications, net of tax of $145, $31 $ 517 $ 107 Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit. See Note P: “Retirement Plans.”

Goodwill and Acquired Intangibl

Goodwill and Acquired Intangible Assets	3 Months Ended
	Mar. 29, 2020
Goodwill and Intangible Assets	M. 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” The changes in the carrying amount of goodwill by reportable segments for the three months ended March 29, 2020, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2019 Goodwill $ 396,483 $ 158,699 $ 361,819 $ 261,996 $ 1,178,997 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 396,483 10,516 7,976 1,456 416,431 AutoGuide acquisition (149 ) — — — (149 ) Foreign currency translation adjustment (6,354 ) — — 5 (6,349 ) Balance at March 29, 2020 Goodwill 389,980 158,699 361,819 262,001 1,172,499 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 389,980 $ 10,516 $ 7,976 $ 1,461 $ 409,933 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: Gross Carrying Amount Accumulated Amortization Foreign Currency Net Carrying Amount (in thousands) Balance, March 29, 2020 Developed technology $ 361,787 $ (286,166 ) $ (6,663 ) $ 68,958 Customer relationships 75,669 (60,406 ) (547 ) 14,716 Tradenames and trademarks 70,120 (38,067 ) (1,406 ) 30,647 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (384,899 ) $ (8,616 ) $ 114,321 Balance, December 31, 2019 Developed technology $ 361,787 $ (279,000 ) $ (5,709 ) $ 77,078 Customer relationships 75,669 (59,077 ) (455 ) 16,137 Tradenames and trademarks 70,120 (36,671 ) (1,184 ) 32,265 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (375,008 ) $ (7,348 ) $ 125,480 Aggregate intangible asset amortization expense for the three months ended March 29, 2020 and March 31, 2019 was $9.9 million and $10.6 million, respectively. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Amortization Expense Year (in thousands) 2020 (remainder) 20,411 2021 20,391 2022 19,498 2023 19,023 2024 18,718 Thereafter 16,280

Net Income Per Common Share

Net Income Per Common Share	3 Months Ended
	Mar. 29, 2020
Net Income per Common Share	N The following table sets forth the computation of basic and diluted net income per common share: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 176,191 $ 109,138 Weighted average common shares-basic 166,589 173,532 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible 7,333 2,186 Convertible note hedge warrant shares (2) 5,492 — Restricted stock units 1,163 1,021 Stock options 134 222 Employee stock purchase plan 25 11 Dilutive potential common shares 14,147 3,440 Weighted average common shares-diluted 180,736 176,972 Net income per common share-basic $ 1.06 $ 0.63 Net income per common share-diluted $ 0.97 $ 0.62 (1) Incremental shares from assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.61, multiplied by 14.6 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 notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.66, multiplied by 14.6 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 months ended March 29, 2020 excludes the effect of the potential vesting of 0.3 million of restricted stock units because the effect would have been anti-dilutive. The computation of diluted net income per common share for the three months ended March 31 2019

Restructuring and Other

Restructuring and Other	3 Months Ended
	Mar. 29, 2020
Restructuring and Other	O During the three months ended March 29, 2020, Teradyne recorded a gain $10.0 million for the decrease in the fair value of the AutoGuide and MiR contingent consideration liabilit i es $1.4 million of acquisition related compensation and expenses and $0.7 million of severance charges related to headcount reductions primarily in Industrial Automation and Semiconductor Test. During the three months ended March 31, 2019, Teradyne recorded an expense of $3.0 million for the increase in the fair value of the MiR contingent consideration liability, $1.3 million of acquisition related compensation and expenses ,

Retirement Plans

Retirement Plans	3 Months Ended
	Mar. 29, 2020
Retirement Plans	P ASC 715, “Compensation—Retirement Benefits” requires an employer with a defined benefit plan or other postretirement benefit plan to recognize an asset or a liability on its balance sheet for the overfunded or underfunded status of the plan. The pension asset or liability represents a difference between the fair value of the pension plan’s assets and the projected benefit obligation at December 31. Teradyne uses a December 31 measurement date for all of its plans. Defined Benefit Pension Plans Teradyne has defined benefit pension plans covering a portion of domestic employees and employees of certain non-U.S. 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 65. Death benefits provide a fixed sum to retirees’ survivors and are available to all retirees. Substantially all of Teradyne’s current U.S. employees could become eligible for these benefits, and the existing benefit obligation relates primarily to those employees. For the three months ended March 29, 2020 and March 31, 2019, Teradyne’s net periodic postretirement benefit cost was comprised of the following: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Service cost $ 11 $ 9 Interest cost 62 85 Amortization of prior service credit (2 ) (48 ) Total net periodic postretirement benefit cost $ 71 $ 46

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 29, 2020
Commitments and Contingencies	Q Purchase Commitments As of March 29, 2020, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments covered by the agreements aggregate to approximately $543.8 million, of which $529.4 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 such as, but not limited to, patent, employment, commercial and environmental matters. Teradyne believes that it has meritorious defenses against all pending claims and intends to vigorously contest them. While it is not possible to predict or determine the outcomes of any pending claims or to provide possible ranges of losses that may arise, Teradyne believes the potential losses associated with all of these actions are unlikely to have a material adverse effect on its business, financial position or results of operations.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 29, 2020
Income Taxes	R 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 March 29, March 31, 2020 2019 US statutory federal tax rate 21.0 % 21.0 % Foreign taxes (5.7 ) (3.1 ) Tax credits (1.9 ) (3.0 ) Discrete benefit related to equity compensation (4.1 ) (4.1 ) Discrete benefit related to release of reserves for uncertain tax positions — (27.6 ) Other, net 1.3 0.7 Effective tax rate 10.6 % (16.1 )% 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 March 29, 2020, 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 March 29, 2020 and December 31, 2019, Teradyne had $21.3 million and $21.2 million, respectively, of reserves for uncertain tax positions. The $0.1 million net increase in reserves for uncertain tax positions is associated with U.S. research and development tax credits generated in the current year. As of March 29, 2020, Teradyne does not anticipate a material change in the balance of unrecognized tax benefits during the next twelve months. Teradyne recognizes interest and penalties related to income tax matters in income tax expense. As of March 29, 2020 and December 31, 2019, $1.6 million and $1.4 million, respectively, of interest and penalties were accrued for uncertain tax positions. For the three months ended March 29, 2020 and March 31, 2019, expense of $0.1 million and $0.3 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 three months ended March 29, 2020 was $7.1 million, or $0.04 per diluted share. The tax savings due to the tax holiday for the three months ended March 31, 2019 was $2.1 million, or $0.01 per diluted share. The tax holiday is scheduled to expire on December 31, 2020.

Segment Information

Segment Information	3 Months Ended
	Mar. 29, 2020
Segment Reporting [Abstract]
Segment Information	S 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 Segment information for the three months ended March 29, 2020 and March 31, 2019 is as follows: Semiconductor Test System Test Industrial Automation Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended March 29, 2020 Revenues $ 484,489 $ 116,076 $ 60,305 $ 43,485 $ — $ 704,355 Income (loss) before taxes (1)(2) 153,816 48,407 (15,335 ) 10,220 (39 ) 197,069 Total assets (3) 921,108 137,056 643,011 106,400 1,012,813 2,820,388 Three Months Ended March 31, 2019 Revenues $ 340,853 $ 58,220 $ 66,136 $ 29,041 $ (151 ) $ 494,099 Income ( loss 83,049 15,340 (5,295 ) 3,628 (2,743 ) 93,979 Total assets (3) 770,967 98,916 596,899 73,066 1,076,795 2,616,643 (1) Included in Corporate and Other are: contingent consideration adjustments, severance charges, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations and acquisition related charges. (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, and inventory charges. (3) Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets. Included in each segment are charges and credits in the following line items in the statements of operations: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Semiconductor Test: Cost of revenues—inventory charge $ 3,026 $ 1,174 Industrial Automation: Restructuring and other—acquisition related expenses and compensation 618 1,261 Corporate and Other: Restructuring and other—MiR contingent consideration adjustment (2,878 ) 3,003 Restructuring and other—AutoGuide contingent consideration adjustment (7,142 ) — Restructuring and other—acquisition related expenses and compensation 741 —

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 29, 2020
Equity [Abstract]
Shareholders' Equity	T Stock Repurchase Program In January 2020, Teradyne’s Board of Directors authorized a new stock repurchase program for up to $1.0 billion of common stock. Effective April 1, 2020, Teradyne suspended its share repurchase program. During the three months ended March 29, 2020, Teradyne repurchased 1.3 million shares of common stock for $79.0 million at an average price of $58.81 per share. During the three months ended March 31, 2019, Teradyne repurchased 4.5 million shares of common stock for $156.5 million at an average price of $35.12 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 2020, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.10 per share. Dividend payments for the three months ended March 29, 2020 were $16.7 million. In January 2019, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.09 per share. Dividend payments for the three months ended March 31, 2019 were $15.6 million.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 29, 2020
Subsequent Events	U. SUBSEQUENT EVENT On May 1, 2020, Teradyne entered into a credit agreement (the “Credit Agreement”) with Truist Bank, as administrative agent and collateral agent, and the lenders party thereto. The Credit Agreement provides for a three Proceeds from the Credit Facility may be used for general corporate purposes and working capital. As of May 4 The interest rates applicable to loans under the Credit Facility are, at Teradyne’s option, equal to either a base rate plus a margin ranging from 0.50% to 1.25% per annum or LIBOR, a minimum of 0.75%, plus a margin ranging from 1.50% to 2.25% per annum, based on the consolidated leverage ratio of Teradyne. In addition, Teradyne will pay a commitment fee on the unused portion of the commitments under the Credit Facility ranging from 0.25% to 0.40% per annum, based on the then applicable consolidated leverage ratio. Teradyne is not required to repay any loans under the Credit Facility prior to maturity, subject to certain customary exceptions. Teradyne is permitted to prepay all or any portion of the loans under the Credit Facility prior to maturity without premium or penalty, other than customary LIBOR breakage costs. The Credit Agreement contains customary events of default, representations, warranties and affirmative and negative covenants that, among other things, limit Teradyne’s ability to sell assets, grant liens on assets, incur other secured indebtedness and make certain investments and restricted payments, all subject to exceptions set forth in the Credit Agreement. The Credit Agreement also requires Teradyne to satisfy two financial ratios measured as of the end of each fiscal quarter: a consolidated leverage ratio and an interest coverage ratio. The Credit Facility is guaranteed by certain of Teradyne’s domestic subsidiaries and collateralized by assets of Teradyne and such subsidiaries, including a pledge of 65% of the capital stock of certain foreign subsidiaries.

Accounting Policies (Policies)

Accounting Policies (Policies)	3 Months Ended
	Mar. 29, 2020
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, 2019 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. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and our markets. Teradyne is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of May 4
Goodwill	Goodwill On January 26, 2017, the Financial Accounting Standards Board (“FASB”) issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment.” 2017-04 2017-04, one-step
Credit Losses	Credit Losses In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” This standard introduced the expected credit losses methodology for the measurement of credit losses on financial assets that are not measured at fair value through net income and replaces the “incurred loss” model with an “expected credit loss” model that requires consideration of a broader range of information to estimate expected credit losses over the lifetime of the asset. Teradyne adopted this standard on January 1, 2020 on a modified retrospective basis. The adoption of ASU 2016-13 did not have a material impact on the consolidated statement of operations, balance sheets, cash flows, or earnings per share.

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 29, 2020
Final Allocation of Purchase Price	The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 41,223 Intangible assets 37,660 Tangible assets acquired and liabilities assumed: Other current assets 3,661 Non-current assets 1,227 Accounts payable and current liabilities (1,223 ) Long-term other liabilities (949 ) Total purchase price $ 81,599
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 $ 24,590 6.0 Customer relationships 7,360 6.0 Trademarks and tradenames 5,450 7.0 Backlog 260 0.3 Total intangible assets $ 37,660 6.1
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 Ended March 31, 2019 (in thousands, except Revenue s $ 495,599 Net income $ 107,289 Net income per common share: Basic $ 0.62 Diluted $ 0.61

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 29, 2020
Revenue from Contract with Customer [Abstract]
Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition	D. REVENUE Disaggregation of Revenue The following table provides information about disaggregated revenue by timing of revenue recognition, primary geographical market, and major product lines. Semiconductor Test Industrial Automation Wireless Test Corporate and Other Total System on Memory System Universal Mobile AutoGuide (in thousands) For the Three Months Ended March 29, 2020 (1) Timing of Revenue Recognition Point in Time $ 348,044 $ 79,398 $ 100,712 $ 47,502 $ 9,097 $ 1,124 $ 41,056 $ — $ 626,933 Over Time 52,095 4,952 15,364 2,195 41 346 2,429 — 77,422 Total $ 400,139 $ 84,350 $ 116,076 $ 49,697 $ 9,138 $ 1,470 $ 43,485 $ — $ 704,355 Geographical Market Asia Pacific $ 362,732 $ 76,110 $ 80,017 $ 10,917 $ 1,593 $ — $ 37,805 $ — $ 569,174 Americas 17,386 6,896 28,291 14,743 3,465 1,470 4,688 — 76,939 Europe, Middle East and Africa 20,021 1,344 7,768 24,037 4,080 — 992 — 58,242 Total $ 400,139 $ 84,350 $ 116,076 $ 49,697 $ 9,138 $ 1,470 $ 43,485 $ — $ 704,355 For the Three Months Ended March 31, 2019 (1) Timing of Revenue Recognition Point in Time $ 238,755 $ 43,775 $ 45,237 $ 55,379 $ 9,106 $ — $ 27,454 $ (151 ) $ 419,555 Over Time 54,051 4,272 12,983 1,651 — — 1,587 — 74,544 Total $ 292,806 $ 48,047 $ 58,220 $ 57,030 $ 9,106 $ — $ 29,041 $ (151 ) $ 494,099 Geographical Market Asia Pacific $ 260,326 $ 38,851 $ 24,285 $ 14,618 $ 1,727 $ — $ 26,019 $ — $ 365,826 Americas 16,167 8,763 26,809 15,803 3,539 — 2,241 (151 ) 73,171 Europe, Middle East and Africa 16,313 433 7,126 26,609 3,840 — 781 — 55,102 Total $ 292,806 $ 48,047 $ 58,220 $ 57,030 $ 9,106 $ — $ 29,041 $ (151 ) $ 494,099 (1) Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “ Revenue from Contracts with Customers.”

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 29, 2020
Composition of Inventories, Net	Inventories, net consisted of the following at March 29, 2020 and December 31, 2019: March 29, December 31, 2020 2019 (in thousands) Raw material $ 102,109 $ 118,595 Work-in-process 39,848 32,695 Finished goods 41,021 45,401 $ 182,978 $ 196,691

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 29, 2020
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 March 29, 2020 and December 31, 2019. March 29, 2020 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 $ 270,460 $ — $ — $ 270,460 Cash equivalents 244,176 78,858 — 323,034 Available-for-sale Commercial paper — 101,947 — 101,947 U.S. Treasury securities — 85,632 — 85,632 Corporate debt securities — 67,467 — 67,467 Certificates of deposit and time deposits — 25,776 — 25,776 Debt mutual funds 5,237 — — 5,237 U.S. government agency securities — 4,402 — 4,402 Non-U.S. — 589 — 589 Equity securities: Mutual funds 20,464 — — 20,464 $ 540,337 $ 364,671 $ — $ 905,008 Derivative assets — 344 — 344 Total $ 540,337 $ 365,015 $ — $ 905,352 Liabilities Contingent consideration $ — $ — $ 20,472 $ 20,472 Derivative liabilities — 254 — 254 Total $ — $ 254 $ 20,472 $ 20,726 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 514,636 $ 78,858 $ — $ 593,494 Marketable securities — 211,001 — 211,001 Long-term marketable securities 25,701 74,812 — 100,513 Prepayments and other current assets — 344 — 344 Total $ 540,337 $ 365,015 $ — $ 905,352 Liabilities Other current liabilities $ — $ 254 $ — $ 254 Contingent consideration — — 662 662 Long-term contingent consideration — — 19,810 19,810 Total $ — $ 254 $ 20,472 $ 20,726 December 31, 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 $ 311,975 $ — $ — 311,975 Cash equivalents 410,285 51,664 — 461,949 Available-for-sale Corporate debt securities — 97,307 — 97,307 Commercial paper — 54,149 — 54,149 U.S. Treasury securities — 42,382 — 42,382 U.S. government agency securities — 9,952 — 9,952 Debt mutual funds 6,888 — — 6,888 Certificates of deposit and time deposits — 4,751 — 4,751 Non-U.S. — 592 — 592 Equity securities: Equity mutual funds 25,772 — — 25,772 $ 754,920 $ 260,797 $ — $ 1,015,717 Derivative assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Contingent consideration $ — $ — $ 39,705 $ 39,705 Derivative liabilities — 203 — 203 Total $ — $ 203 $ 39,705 $ 39,908 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 722,260 $ 51,664 $ — $ 773,924 Marketable securities — 137,303 — 137,303 Long-term marketable securities 32,660 71,830 — 104,490 Prepayments and other current assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Other accrued liabilities $ — $ 203 $ — $ 203 Contingent consideration — — 9,106 9,106 Long-term contingent consideration — — 30,599 30,599 Total $ — $ 203 $ 39,705 $ 39,908
Schedule of Changes in Fair Value of Level 3 Contingent Consideration	Changes in the fair value of Level 3 contingent consideration for the three months ended March 29, 2020 and March 31, 2019 were as follows: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 39,705 $ 70,543 Foreign currency impact (361 ) (610 ) Payments (a)(b) (8,852 ) (34,590 ) Fair value adjustment (c)(d) (10,020 ) 2,970 Balance at end of period $ 20,472 $ 38,313 (a) In the three months ended March 29, 2020, Teradyne paid $8.9 million of contingent consideration for the earn-out (b) In the three months ended March 31, 2019, Teradyne paid $30.8 million and $3.8 million of contingent consideration for the earn-outs in connection with the acquisitions of MiR and Universal Robots A/S (“Universal Robots”), respectively. (c) In the three months ended March 29, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisitions of MiR and AutoGuide decreased by $2.9 million and $7.1 million, respectively, due to lower forecasted results. (d) In the three months ended March 31, 2019, the fair value of contingent consideration for the earn-out
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 March 29, 2020 Fair Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent consideration (AutoGuide) $ 19,810 Monte Carlo Simulation Revenue volatility 14.0 % Discount Rate 4.4 % Contingent consideration (MiR) $ 662 Monte Carlo Simulation Revenue volatility 16.0 % Discount Rate 2.2 %
Schedule of Carrying Amounts and Fair Values of Financial Instruments	The carrying amounts and fair values of Teradyne’s financial instruments at March 29, 2020 and December 31, 2019 were as follows: March 29, 2020 December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 593,494 $ 593,494 $ 773,924 $ 773,924 Marketable securities 311,514 311,514 241,793 241,793 Derivative assets 344 344 528 528 Liabilities Contingent consideration 20,472 20,472 39,705 39,705 Derivative liabilities 254 254 203 203 Convertible debt (1) 398,466 829,438 394,687 1,010,275 (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 March 29, 2020 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Commercial paper $ 101,915 $ 33 $ (1 ) $ 101,947 $ 1,296 U.S. Treasury securities 82,680 2,958 (6 ) 85,632 96 Corporate debt securities 65,696 2,951 (1,180 ) 67,467 40,891 Certificates of deposit and time deposits 25,769 7 — 25,776 — Debt mutual funds 5,089 148 — 5,237 — U.S. government agency securities 4,335 67 — 4,402 — Non-U.S. 589 — — 589 — $ 286,073 $ 6,164 $ (1,187 ) $ 291,050 $ 42,283 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 210,722 $ 430 $ (151 ) $ 211,001 $ 32,037 Long-term marketable securities 75,351 5,734 (1,036 ) 80,049 10,246 $ 286,073 $ 6,164 $ (1,187 ) $ 291,050 $ 42,283 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 137,144 $ 160 $ (1 ) $ 137,303 $ 2,922 Long-term marketable securities 74,452 4,527 (261 ) 78,718 21,077 $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999
Contractual Maturities of Investments Held	The contractual maturities of investments in available-for-sale March 29, 2020 Cost Fair Market Value (in thousands) Due within one year $ 210,722 $ 211,001 Due after 1 year through 5 years 18,933 19,465 Due after 5 years through 10 years 12,440 13,160 Due after 10 years 38,889 42,187 Total $ 280,984 $ 285,813
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	The following table summarizes the fair value of derivative instruments as of March 29, 2020 and December 31, 2019: Balance Sheet Location March 29, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 344 $ 528 Foreign exchange contracts Other current liabilities (254 ) (203 ) Total derivatives $ 90 $ 325
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 months ended March 29, 2020 and March 31, 2019: Location of Losses For the Three Months Ended Recognized in March 29, March 31, 2020 2019 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 4,011 $ 3,934 (1) The table does not reflect the corresponding gains and losses from the remeasurement of the (2) For the three months ended March 29, 2020 and March 31, 2019, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $2.0

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 29, 2020
Components of Convertible Senior Notes	The below tables represent the key components of Teradyne’s convertible senior notes: March 29, December 31, (in thousands) Debt Principal $ 459,987 $ 460,000 Unamortized discount 61,521 65,313 Net Carrying amount of convertible debt $ 398,466 $ 394,687 For the Three Months Ended March 29, March 31, (in thousands) Contractual interest expense on the coupon $ 1,438 $ 1,438 Amortization of the discount component and debt issue fees recognized as interest expense 3,792 3,608 Total interest expense on the convertible debt $ 5,230 $ 5,046

Prepayments (Tables)

Prepayments (Tables)	3 Months Ended
	Mar. 29, 2020
Schedule of Prepayments and other assets	Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: March 29, December 31, 2020 2019 (in thousands) Contract manufacturer and supplier prepayments $ 173,082 $ 143,392 Prepaid taxes 9,667 8,046 Prepaid maintenance and other services 10,828 8,503 Other prepayments 17,890 16,753 Total prepayments $ 211,467 $ 176,694

Deferred Revenue and Customer_2

Deferred Revenue and Customer Advances (Tables)	3 Months Ended
	Mar. 29, 2020
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: March 29, December 31, 2020 2019 (in thousands) Maintenance, se r $ 68,483 $ 63,815 Extended warranty 33,503 30,677 Customer advances, undelivered elements and other 47,620 56,358 Total deferred revenue and customer advances $ 149,606 $ 150,850

Product Warranty (Tables)

Product Warranty (Tables)	3 Months Ended
	Mar. 29, 2020
Other Accrued Liabilities	Related costs are charged to the warranty accrual as incurred. The balance below is included in other accrued liabilities. For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 8,996 $ 7,909 Acquisition — 14 Accruals for warranties issued during the period 5,066 3,066 Accruals related to pre-existing 1,056 1,330 Settlements made during the period (4,147 ) (4,567 ) Balance at end of period $ 10,971 $ 7,752
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. For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Balance at beginning of period $ 30,677 $ 27,422 Deferral of new extended warranty revenue 7,600 5,820 Recognition of extended warranty deferred revenue (4,774 ) (6,000 ) Balance at end of period $ 33,503 $ 27,242

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 29, 2020
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 Three Months Ended March 29, March 31, 2020 2019 Risk-free interest rate 1.5 % 2.6 % Teradyne volatility-historical 34.9 % 31.8 % NYSE Composite Index volatility-historical 11.4 % 12.0 % Dividend yield 0.6 % 1.0 %
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 Three Months Ended March 29, March 31, 2020 2019 Expected life (years) 5.0 5.0 Risk-free interest rate 1.6 % 2.6 % Volatility-historical 31.6 % 30.1 % Dividend yield 0.6 % 1.0 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive (Loss) Income (Tables)	3 Months Ended
	Mar. 29, 2020
Changes in Accumulated Other Comprehensive (Loss) Income	Changes in accumulated other comprehensive (loss) income, 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) Three Months Ended March 29, 2020 Balance at December 31, 2019, net of tax of $0, $946, $(1,124) $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) Other comprehensive income (loss) before reclassifications, net of tax of $0, $187, $0 (8,779 ) 1,037 — (7,742 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(145), $0 — (515 ) (2 ) (517 ) Net current period other comprehensive income (loss), net of tax of $0, $42, $0 (8,779 ) 522 (2 ) (8,259 ) Balance at March 29, 2020, net of tax of $0, $988, $(1,124) $ (32,293 ) $ 4,002 $ 1,178 $ (27,113 ) Three Months Ended March 31 Balance at December 31, 2018, net of tax of $0, $(521), $(1,081) $ (12,523 ) $ (1,845 ) $ 1,328 $ (13,040 ) Other comprehensive income (loss) before reclassifications, net of tax of $0, $577, $0 (4,659 ) 2,100 — (2,559 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(20), $(11) — (70 ) (37 ) (107 ) Net current period other comprehensive income (loss), net of tax of $0, $557, $(11) (4,659 ) 2,030 (37 ) (2,666 ) Balance as March 31, 2019, net of tax of $0, $36, $(1,092) $ (17,182 ) $ 185 $ 1,291 $ (15,706 )
Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations	Reclassifications out of accumulated other comprehensive (loss) income to the statement of operations for the three months ended March 29, 2020 and March 31, 2019 were as follows: For the Three Months Ended Affected Line Item in the Statements of Operations March 29, March 31, 2020 2019 Details about Accumulated Other Comprehensive ( loss (in thousands) Available-for-sale Unrealized gains, net of tax of $145, $20 $ 515 $ 70 Interest income Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $0, $11 2 37 (a) Total reclassifications, net of tax of $145, $31 $ 517 $ 107 Net income (a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit. See Note P: “Retirement Plans.”

Goodwill and Acquired Intangi_2

Goodwill and Acquired Intangible Assets (Tables)	3 Months Ended
	Mar. 29, 2020
Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by reportable segments for the three months ended March 29, 2020, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2019 Goodwill $ 396,483 $ 158,699 $ 361,819 $ 261,996 $ 1,178,997 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 396,483 10,516 7,976 1,456 416,431 AutoGuide acquisition (149 ) — — — (149 ) Foreign currency translation adjustment (6,354 ) — — 5 (6,349 ) Balance at March 29, 2020 Goodwill 389,980 158,699 361,819 262,001 1,172,499 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 389,980 $ 10,516 $ 7,976 $ 1,461 $ 409,933
Schedule of Estimated Intangible Assets Amortization Expense	Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Amortization Expense Year (in thousands) 2020 (remainder) 20,411 2021 20,391 2022 19,498 2023 19,023 2024 18,718 Thereafter 16,280
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: Gross Carrying Amount Accumulated Amortization Foreign Currency Net Carrying Amount (in thousands) Balance, March 29, 2020 Developed technology $ 361,787 $ (286,166 ) $ (6,663 ) $ 68,958 Customer relationships 75,669 (60,406 ) (547 ) 14,716 Tradenames and trademarks 70,120 (38,067 ) (1,406 ) 30,647 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (384,899 ) $ (8,616 ) $ 114,321 Balance, December 31, 2019 Developed technology $ 361,787 $ (279,000 ) $ (5,709 ) $ 77,078 Customer relationships 75,669 (59,077 ) (455 ) 16,137 Tradenames and trademarks 70,120 (36,671 ) (1,184 ) 32,265 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (375,008 ) $ (7,348 ) $ 125,480

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	3 Months Ended
	Mar. 29, 2020
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 March 29, March 31, 2020 2019 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 176,191 $ 109,138 Weighted average common shares-basic 166,589 173,532 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible 7,333 2,186 Convertible note hedge warrant shares (2) 5,492 — Restricted stock units 1,163 1,021 Stock options 134 222 Employee stock purchase plan 25 11 Dilutive potential common shares 14,147 3,440 Weighted average common shares-diluted 180,736 176,972 Net income per common share-basic $ 1.06 $ 0.63 Net income per common share-diluted $ 0.97 $ 0.62 (1) Incremental shares from assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.61, multiplied by 14.6 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 notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.66, multiplied by 14.6 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)	3 Months Ended
	Mar. 29, 2020
Defined Benefit Pension Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three months ended March 29, 2020 and March 31, 2019, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended March 29, 2020 March 31, 2019 United States Foreign United States Foreign (in thousands) Service cost $ 433 $ 201 $ 405 $ 188 Interest cost 1,522 115 1,795 173 Expected return on plan assets (1,233 ) (15 ) (1,511 ) (7 ) Total net periodic pension cost $ 722 $ 301 $ 689 $ 354
Postretirement Benefit Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three months ended March 29, 2020 and March 31, 2019, Teradyne’s net periodic postretirement benefit cost was comprised of the following: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Service cost $ 11 $ 9 Interest cost 62 85 Amortization of prior service credit (2 ) (48 ) Total net periodic postretirement benefit cost $ 71 $ 46

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 29, 2020
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 March 29, March 31, 2020 2019 US statutory federal tax rate 21.0 % 21.0 % Foreign taxes (5.7 ) (3.1 ) Tax credits (1.9 ) (3.0 ) Discrete benefit related to equity compensation (4.1 ) (4.1 ) Discrete benefit related to release of reserves for uncertain tax positions — (27.6 ) Other, net 1.3 0.7 Effective tax rate 10.6 % (16.1 )%

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 29, 2020
Segment Information	Segment information for the three months ended March 29, 2020 and March 31, 2019 is as follows: Semiconductor Test System Test Industrial Automation Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended March 29, 2020 Revenues $ 484,489 $ 116,076 $ 60,305 $ 43,485 $ — $ 704,355 Income (loss) before taxes (1)(2) 153,816 48,407 (15,335 ) 10,220 (39 ) 197,069 Total assets (3) 921,108 137,056 643,011 106,400 1,012,813 2,820,388 Three Months Ended March 31, 2019 Revenues $ 340,853 $ 58,220 $ 66,136 $ 29,041 $ (151 ) $ 494,099 Income ( loss 83,049 15,340 (5,295 ) 3,628 (2,743 ) 93,979 Total assets (3) 770,967 98,916 596,899 73,066 1,076,795 2,616,643 (1) Included in Corporate and Other are: contingent consideration adjustments, severance charges, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations and acquisition related charges. (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, and inventory charges. (3) Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.
Schedule of Segment Reporting Information by Segment Charges	Included in each segment are charges and credits in the following line items in the statements of operations: For the Three Months Ended March 29, March 31, 2020 2019 (in thousands) Semiconductor Test: Cost of revenues—inventory charge $ 3,026 $ 1,174 Industrial Automation: Restructuring and other—acquisition related expenses and compensation 618 1,261 Corporate and Other: Restructuring and other—MiR contingent consideration adjustment (2,878 ) 3,003 Restructuring and other—AutoGuide contingent consideration adjustment (7,142 ) — Restructuring and other—acquisition related expenses and compensation 741 —

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail)	Nov. 13, 2019USD ($)	Apr. 25, 2018USD ($)	Jan. 30, 2019USD ($)	Mar. 29, 2020USD ($)	Jan. 31, 2019USD ($)
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total preliminary purchase price		$ 81,599,000
Arrangement range of outcomes value high				$ 61,400,000
Goodwill, not deductible for tax purposes		$ 41,200,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		6 years 1 month 6 days
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
Autoguide LLC [Member]
Business Acquisition [Line Items]
Arrangement range of outcomes value high				$ 106,900,000
Autoguide LLC [Member] | Industrial Automation [Member]
Business Acquisition [Line Items]
Total preliminary purchase price	$ 81,600,000
Cash paid to acquire outstanding common and preferred stock	57,600,000
Contingent consideration	$ 24,000,000
Quantity of material to be transported				4,500
Business acquisition percentage of equity	100.00%

Final Allocation of Purchase Pr

Final Allocation of Purchase Price (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019	Apr. 25, 2018
Business Acquisition [Line Items]
Goodwill	$ 409,933	$ 416,431
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Goodwill			$ 41,223
Intangible assets			37,660
Other current assets			3,661
Non-current assets			1,227
Accounts payable and current liabilities			(1,223)
Long-term other liabilities			(949)
Total purchase price			$ 81,599

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	$ 37,660
Total intangible assets, estimated useful life, years	6 years 1 month 6 days
Developed technology
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 24,590
Total intangible assets, estimated useful life, years	6 years
Customer Relationships
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 7,360
Total intangible assets, estimated useful life, years	6 years
Trademarks and tradenames
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 5,450
Total intangible assets, estimated useful life, years	7 years
Customer backlog
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 260
Total intangible assets, estimated useful life, years	3 months 18 days

Pro Forma Results Under Acquisi

Pro Forma Results Under Acquisition (Detail) - Mobile Industrial Robots (MiR) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)$ / shares
Business Acquisition [Line Items]
Revenues | $	$ 495,599
Net income | $	$ 107,289
Net income per common share, basic | $ / shares	$ 0.62
Net income per common share, diluted | $ / shares	$ 0.61

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Deferred Revenue And Customer Advances	$ 39.5	$ 19.5
Trade Accounts Receivable	$ 46.8	$ 41.7
Short-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	66.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	0 months
Long-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	26.00%
Long-term Contract with Customer [Member] | Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	0 months
Long-term Contract with Customer [Member] | Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	0 months

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
		Mar. 29, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total	[1]	$ 704,355	$ 494,099
Semiconductor Test
Disaggregation of Revenue [Line Items]
Total		484,489	340,853
System Test
Disaggregation of Revenue [Line Items]
Total	[1]	116,076	58,220
Industrial Automation
Disaggregation of Revenue [Line Items]
Total		60,305	66,136
Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	43,485	29,041
Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]		(151)
Point in Time
Disaggregation of Revenue [Line Items]
Total	[1]	626,933	419,555
Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	[1]	100,712	45,237
Point in Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	41,056	27,454
Point in Time | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]		(151)
Over Time
Disaggregation of Revenue [Line Items]
Total	[1]	77,422	74,544
Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	[1]	15,364	12,983
Over Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	2,429	1,587
Over Time | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]
Americas
Disaggregation of Revenue [Line Items]
Total	[1]	76,939	73,171
Americas | System Test
Disaggregation of Revenue [Line Items]
Total	[1]	28,291	26,809
Americas | Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	4,688	2,241
Americas | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]		(151)
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total	[1]	58,242	55,102
Europe, Middle East and Africa | System Test
Disaggregation of Revenue [Line Items]
Total	[1]	7,768	7,126
Europe, Middle East and Africa | Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	992	781
Europe, Middle East and Africa | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]
Asia Pacific
Disaggregation of Revenue [Line Items]
Total	[1]	569,174	365,826
Asia Pacific | System Test
Disaggregation of Revenue [Line Items]
Total	[1]	80,017	24,285
Asia Pacific | Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	37,805	26,019
Asia Pacific | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]
SOC | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	400,139	292,806
SOC | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	348,044	238,755
SOC | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	52,095	54,051
SOC | Americas | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	17,386	16,167
SOC | Europe, Middle East and Africa | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	20,021	16,313
SOC | Asia Pacific | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	362,732	260,326
Memory | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	84,350	48,047
Memory | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	79,398	43,775
Memory | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	4,952	4,272
Memory | Americas | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	6,896	8,763
Memory | Europe, Middle East and Africa | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	1,344	433
Memory | Asia Pacific | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	76,110	38,851
Universal Robots (UR) | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	49,697	57,030
Universal Robots (UR) | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	47,502	55,379
Universal Robots (UR) | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	2,195	1,651
Universal Robots (UR) | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	14,743	15,803
Universal Robots (UR) | Europe, Middle East and Africa | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	24,037	26,609
Universal Robots (UR) | Asia Pacific | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	10,917	14,618
MiR | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	9,138	9,106
MiR | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	9,097	9,106
MiR | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	41
MiR | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	3,465	3,539
MiR | Europe, Middle East and Africa | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	4,080	3,840
MiR | Asia Pacific | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,593	$ 1,727
Autoguide LLC [Member] | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,470
Autoguide LLC [Member] | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,124
Autoguide LLC [Member] | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	346
Autoguide LLC [Member] | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,470
Autoguide LLC [Member] | Europe, Middle East and Africa | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]
Autoguide LLC [Member] | Asia Pacific | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]
[1]	Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.

Disaggregated Revenue by Prim_2

Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Accounting Policies [Abstract]
Revenue on leases	$ 1.8	$ 1.7

Composition of Inventories, Net

Composition of Inventories, Net (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Inventory [Line Items]
Raw material	$ 102,109	$ 118,595
Work-in-process	39,848	32,695
Finished goods	41,021	45,401
Inventories, net	$ 182,978	$ 196,691

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	Mar. 29, 2020	Dec. 31, 2019
Inventory [Line Items]
Inventory reserves	$ 105.3	$ 103.6

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Dec. 31, 2019
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized gain	$ 1,400,000	$ 100,000
Available-for-sale securities, realized loss	100,000	100,000
Fair market value of investments with unrealized losses less than one year	42,300,000		$ 23,600,000
Unrealized Gain (loss) on contracts	2,000,000	3,200,000
Equity securities unrealized gain loss		$ 2,800,000
Equity securities unrealized loss	6,000,000
Debt Mutual Funds
Financial Instruments and Fair Value [Line Items]
Available for sale securities with out contractual maturity date	5,200,000
Mobile Industrial Robots (MiR)
Financial Instruments and Fair Value [Line Items]
Maximum amount of contingent consideration paid for acquisition	61,400,000
Autoguide LLC [Member]
Financial Instruments and Fair Value [Line Items]
Maximum amount of contingent consideration paid for acquisition	106,900,000
Foreign Exchange Contracts
Financial Instruments and Fair Value [Line Items]
Unrealized Gain (loss) on contracts	$ 132,100,000		$ 144,900,000

Schedule of Fair Value of Finan

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 291,050	$ 216,021
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	85,632	42,382
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	101,947	54,149
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	67,467	97,307
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	25,776	4,751
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,402	9,952
Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	5,237	6,888
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	589	592
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	905,008	1,015,717
Derivative assets	344	528
Total	905,352	1,016,245
Contingent consideration	20,472	39,705
Derivative liabilities	254	203
Total	20,726	39,908
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	270,460	311,975
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	323,034	461,949
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	85,632	42,382
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	101,947	54,149
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	67,467	97,307
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	25,776	4,751
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,402	9,952
Fair Value, Measurements, Recurring | Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	5,237	6,888
Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	589	592
Fair Value, Measurements, Recurring | Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	20,464	25,772
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	540,337	754,920
Total	540,337	754,920
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	270,460	311,975
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	244,176	410,285
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	5,237	6,888
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	20,464	25,772
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	364,671	260,797
Derivative assets	344	528
Total	365,015	261,325
Derivative liabilities	254	203
Total	254	203
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	78,858	51,664
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	85,632	42,382
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	101,947	54,149
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	67,467	97,307
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	25,776	4,751
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	4,402	9,952
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	589	592
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration	20,472	39,705
Total	$ 20,472	$ 39,705

Schedule of Reported Financial

Schedule of Reported Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 905,352	$ 1,016,245
Liabilities	20,726	39,908
Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	254	203
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	593,494	773,924
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	211,001	137,303
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	100,513	104,490
Prepayments and other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	344	528
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	662	9,106
Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	19,810	30,599
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	540,337	754,920
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	514,636	722,260
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	25,701	32,660
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	365,015	261,325
Liabilities	254	203
Significant Other Observable Inputs (Level 2) | Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	254	203
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	78,858	51,664
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	211,001	137,303
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	74,812	71,830
Significant Other Observable Inputs (Level 2) | Prepayments and other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	344	528
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	20,472	39,705
Significant Unobservable Inputs (Level 3) | Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	662	9,106
Significant Unobservable Inputs (Level 3) | Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	$ 19,810	$ 30,599

Schedule of Changes in Fair Val

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 39,705	$ 70,543
Foreign currency impact	(361)	(610)
Payments	(8,852)	(34,590)
Fair value adjustment	(10,020)	2,970
Balance at end of period	$ 20,472	$ 38,313

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
	Mar. 29, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	$ 8,852	$ 27,615
Increase (decrease) in contingent consideration	(10,020)	2,970
Universal Robots (UR)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration		30,800
Increase (decrease) in contingent consideration		3,800
Avionics Interface Technologies, LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	8,900
MiR
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	2,900
Increase (decrease) in contingent consideration		$ 3,000
Autoguide LLC [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Increase (decrease) in contingent consideration	$ 7,100

Quantitative Information Associ

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail) - Monte Carlo Simulation $ in Thousands	3 Months Ended
	Mar. 29, 2020USD ($)
Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Target achievement, volatility	16.00%
Discount rate	2.20%
Autoguide LLC [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Target achievement, volatility	14.00%
Discount rate	4.40%
Significant Unobservable Inputs (Level 3) | Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration	$ 662
Significant Unobservable Inputs (Level 3) | Autoguide LLC [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration	$ 19,810

Schedule of Carrying Amounts an

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Marketable securities	$ 291,050	$ 216,021
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	593,494	773,924
Marketable securities	311,514	241,793
Derivative assets	344	528
Contingent consideration	20,472	39,705
Derivative liabilities	254	203
Convertible debt	398,466	394,687
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	593,494	773,924
Marketable securities	311,514	241,793
Derivative assets	344	528
Contingent consideration	20,472	39,705
Derivative liabilities	254	203
Convertible debt	$ 829,438	$ 1,010,275

Schedule of Available for Sale

Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 286,073	$ 211,596
Available-for-sale marketable securities, Unrealized Gain	6,164	4,687
Available-for-sale marketable securities, Unrealized (Loss)	(1,187)	(262)
Available-for-sale marketable securities, Fair Market Value	291,050	216,021
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	42,283	23,999
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	82,680	42,167
Available-for-sale marketable securities, Unrealized Gain	2,958	431
Available-for-sale marketable securities, Unrealized (Loss)	(6)	(216)
Available-for-sale marketable securities, Fair Market Value	85,632	42,382
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	96	17,556
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	101,915	54,124
Available-for-sale marketable securities, Unrealized Gain	33	26
Available-for-sale marketable securities, Unrealized (Loss)	(1)	(1)
Available-for-sale marketable securities, Fair Market Value	101,947	54,149
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	1,296	1,391
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	65,696	93,267
Available-for-sale marketable securities, Unrealized Gain	2,951	4,081
Available-for-sale marketable securities, Unrealized (Loss)	(1,180)	(41)
Available-for-sale marketable securities, Fair Market Value	67,467	97,307
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	40,891	2,009
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	25,769	4,751
Available-for-sale marketable securities, Unrealized Gain	7
Available-for-sale marketable securities, Fair Market Value	25,776	4,751
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	4,335	9,942
Available-for-sale marketable securities, Unrealized Gain	67	14
Available-for-sale marketable securities, Unrealized (Loss)	0	(4)
Available-for-sale marketable securities, Fair Market Value	4,402	9,952
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	0	3,043
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	5,089	6,753
Available-for-sale marketable securities, Unrealized Gain	148	135
Available-for-sale marketable securities, Fair Market Value	5,237	6,888
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	589	592
Available-for-sale marketable securities, Fair Market Value	$ 589	$ 592

Schedule of Reported Available

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 286,073	$ 211,596
Available-for-sale marketable securities, Unrealized Gain	6,164	4,687
Available-for-sale marketable securities, Unrealized (Loss)	(1,187)	(262)
Available-for-sale marketable securities, Fair Market Value	291,050	216,021
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	42,283	23,999
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	210,722	137,144
Available-for-sale marketable securities, Unrealized Gain	430	160
Available-for-sale marketable securities, Unrealized (Loss)	(151)	(1)
Available-for-sale marketable securities, Fair Market Value	211,001	137,303
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	32,037	2,922
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	75,351	74,452
Available-for-sale marketable securities, Unrealized Gain	5,734	4,527
Available-for-sale marketable securities, Unrealized (Loss)	(1,036)	(261)
Available-for-sale marketable securities, Fair Market Value	80,049	78,718
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 10,246	$ 21,077

Contractual Maturities of Inves

Contractual Maturities of Investments in Debt Securities Held (Detail) $ in Thousands	Mar. 29, 2020USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 210,722
Due after 1 year through 5 years, cost	18,933
Due after 5 years through 10 years, cost	12,440
Due after 10 years, cost	38,889
Total, cost	280,984
Due within one year, fair market value	211,001
Due after 1 year through 5 years, fair market value	19,465
Due after 5 years through 10 years, fair market value	13,160
Due after 10 years, fair maket value	42,187
Total, fair market value	$ 285,813

Schedule of Derivative Instrume

Schedule of Derivative Instruments in Statement of Financial Position at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative assets (liabilities), net	$ 90	$ 325
Not Designated as Hedging Instrument | Foreign currency forward contracts | Prepayments
Derivatives, Fair Value [Line Items]
Derivative assets	344	528
Not Designated as Hedging Instrument | Foreign currency forward contracts | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (254)	$ (203)

Schedule of Effect of Derivativ

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Losses on derivatives recognized in statements of operations	$ 4,011	$ 3,934

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
	Mar. 29, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on foreign currency transactions	$ 2	$ 3.2

Debt - Additional Information (

Debt - Additional Information (Detail) $ / shares in Units, $ in Thousands, shares in Millions	Dec. 12, 2016USD ($)Customershares	Mar. 29, 2020USD ($)$ / sharesshares	Mar. 31, 2019USD ($)shares	Dec. 31, 2019USD ($)	Dec. 31, 2016$ / shares
Debt Instrument
Repurchase of common stock		$ 79,039	$ 156,468
Repurchase of stock, shares | shares		1.3	4.5
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Aggregate principal amount	$ 460,000	$ 459,987		$ 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	$ 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, conversion option expiration date	Sep. 15, 2023
Debt instrument conversion price | $ / shares		$ 31.61			$ 31.61
Shares that would be issued upon conversion | shares		14.6
Strike price per share of warrant | $ / shares		$ 39.66
Debt instrument, convertible, carrying amount of equity component		$ 100,800
Debt instrument, effective annual interest rate		5.00%
Financing cost		$ 7,200	$ 4,100
Debt issuance costs, amortization period		7 years
Unamortized discount		$ 61,500
Debt Instrument, convertible, remaining discount amortization period		3 years 8 months 12 days
Value of notes converted		$ 798,300
Debt Instrument, Face Amount	$ 460,000	$ 459,987		$ 460,000
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
Aggregate principal amount	$ 1,000
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%
Debt Instrument, Face Amount	$ 1,000

Components of Convertible Senio

Components of Convertible Senior Notes (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019	Dec. 12, 2016
Debt Instrument
Net carrying amount of convertible debt	$ 398,466	$ 394,687
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Debt principal	459,987	460,000	$ 460,000
Unamortized discount	61,521	65,313
Net carrying amount of convertible debt	$ 398,466	$ 394,687

Interest Expense on Convertible

Interest Expense on Convertible Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Debt Instrument
Contractual interest expense on the coupon	$ 1,438	$ 1,438
Amortization of the discount component and debt issue fees recognized as interest expense	3,792	3,608
Total interest expense on the convertible debt	$ 5,230	$ 5,046

Schedule of Prepayments and Oth

Schedule of Prepayments and Other Assets (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019
Prepaid And Other Current Assets [Line Items]
Contract manufacturer and supplier prepayments	$ 173,082	$ 143,392
Prepaid taxes	9,667	8,046
Prepaid maintenance and other services	10,828	8,503
Other prepayments	17,890	16,753
Total prepayments	$ 211,467	$ 176,694

Deferred Revenue and Customer_3

Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Mar. 29, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Deferred Revenue Arrangement
Maintenance, service and training	$ 68,483	$ 63,815
Extended warranty	33,503	30,677	$ 27,242	$ 27,422
Customer advances, undelivered performance obligations and other	47,620	56,358
Total deferred revenue and customer advances	$ 149,606	$ 150,850

Warranty Accrual Included in Ot

Warranty Accrual Included in Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 8,996	$ 7,909
Acquisition		14
Accruals for warranties issued during the period	5,066	3,066
Accruals related to pre-existing warranties	1,056	1,330
Settlements made during the period	(4,147)	(4,567)
Balance at end of period	$ 10,971	$ 7,752

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
	Mar. 29, 2020	Mar. 31, 2019
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 30,677	$ 27,422
Deferral of new extended warranty revenue	7,600	5,820
Recognition of extended warranty deferred revenue	(4,774)	(6,000)
Balance at end of period	$ 33,503	$ 27,242

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - $ / shares shares in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award
Stock price	$ 72.10	$ 36.75
Stock Options | Measurement Input, Expected Dividend Payment [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Estimated annual dividend amount per share	$ 0.40	$ 72.10
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
Percentage of awards vesting on the first anniversary of grant date	100.00%
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
TSR Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Total shareholder return performance measurement period	3 years	3 years
Share-based compensation arrangement by share-based payment award, description	capped at four times the grant date value for grants prior to 2019
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
Weighted average grant date fair value of restricted stock units granted	$ 89.93	$ 48.47
Stock price	0.36	$ 36.75
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	$ 0.40
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	0.00%	0.00%
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	200.00%	200.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of common stock price paid	100.00%
PBIT Performance-Based Restricted Stock Units
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	$ 70.94	$ 35.67
Service-Based Restricted Stock Units | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted	0.4	0.6
Weighted average grant date fair value of restricted stock units granted	$ 70.98	$ 35.88
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	$ 20.67	$ 10.26

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	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	1.50%	2.60%
Expected historical volatility	34.90%	31.80%
Dividend yield	0.60%	1.00%
New York Stock Exchange Composite Index
Share-based Compensation Arrangement by Share-based Payment Award
Expected historical volatility	11.40%	12.00%

Schedule of Estimated Fair Va_2

Schedule of Estimated Fair Value of Stock Options Grant Using Black Scholes Option Pricing Model (Detail) - Stock Options	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award
Expected life (years)	5 years	5 years
Risk-free interest rate	1.60%	2.60%
Volatility-historical	31.60%	30.10%
Dividend yield	0.60%	1.00%

Changes in Accumulated Other Co

Changes in Accumulated Other Comprehensive (Loss) Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,480,158	$ 1,522,354
Other comprehensive loss	(8,259)	(2,666)
Balance	1,550,673	1,470,228
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(23,514)	(12,523)
Other comprehensive loss before reclassifications, net of tax	(8,779)	(4,659)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0
Other comprehensive loss	(8,779)	(4,659)
Balance	(32,293)	(17,182)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	3,480	(1,845)
Other comprehensive loss before reclassifications, net of tax	1,037	2,100
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(515)	(70)
Other comprehensive loss	522	2,030
Balance	4,002	185
Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	1,180	1,328
Other comprehensive loss before reclassifications, net of tax	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(2)	(37)
Other comprehensive loss	(2)	(37)
Balance	1,178	1,291
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(18,854)	(13,040)
Other comprehensive loss before reclassifications, net of tax	(7,742)	(2,559)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(517)	(107)
Other comprehensive loss	(8,259)	(2,666)
Balance	$ (27,113)	$ (15,706)

Changes in Accumulated Other _2

Changes in Accumulated Other Comprehensive (Loss) Income (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss), tax	$ (145)	$ (31)
Foreign currency translation adjustments, tax	0	0	$ 0	$ 0
Unrealized (losses) gains on marketable securities, tax	988	36	946	(521)
Retirement plans prior service benefit, tax	(1,124)	(1,092)	$ (1,124)	$ (1,081)
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
Unrealized (Losses) Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	187	577
Amounts reclassified from accumulated other comprehensive income (loss), tax	(145)	(20)
Other comprehensive income (loss), tax	42	557
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	0	(11)
Other comprehensive income (loss), tax	$ 0	$ (11)

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)	$ 515	$ 70
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	2	37
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	$ 517	$ 107

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 145	$ 31
Unrealized (Losses) Gains on Marketable Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	145	20
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 0	$ 11

Goodwill and Acquired Intangi_3

Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Line Items]
Acquired intangible assets amortization	$ 9,891	$ 10,634

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Mar. 29, 2020
Goodwill [Line Items]
Foreign currency translation adjustment	$ (6,349)
Goodwill	1,178,997	$ 1,172,499
Accumulated impairment losses	(762,566)	(762,566)
Goodwill	416,431	409,933
Autoguide LLC
Goodwill [Line Items]
Goodwill	(149)
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	(6,354)
Goodwill	396,483	389,980
Goodwill	396,483	389,980
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]
Foreign currency translation adjustment	5
Goodwill	261,996	262,001
Accumulated impairment losses	(260,540)	(260,540)
Goodwill	1,456	1,461
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	9 Months Ended	12 Months Ended
	Sep. 29, 2019	Dec. 31, 2019	Mar. 29, 2020
Finite-Lived Intangible Assets
Gross Carrying Amount		$ 507,836	$ 507,836
Accumulated Amortization		(375,008)	(384,899)
Foreign Currency Translation Adjustment	$ (8,616)	(7,348)
Net Carrying Amount		125,480	114,321
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount		361,787	361,787
Accumulated Amortization		(279,000)	(286,166)
Foreign Currency Translation Adjustment	(6,663)	(5,709)
Net Carrying Amount		77,078	68,958
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount		75,669	75,669
Accumulated Amortization		(59,077)	(60,406)
Foreign Currency Translation Adjustment	(547)	(455)
Net Carrying Amount		16,137	14,716
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount		70,120	70,120
Accumulated Amortization		(36,671)	(38,067)
Foreign Currency Translation Adjustment	$ (1,406)	(1,184)
Net Carrying Amount		32,265	30,647
Backlog
Finite-Lived Intangible Assets
Gross Carrying Amount		260	260
Accumulated Amortization		$ (260)	$ (260)

Schedule of Estimated Intangibl

Schedule of Estimated Intangible Asset Amortization Expense (Detail) $ in Thousands	Mar. 29, 2020USD ($)
Finite-Lived Intangible Assets
2020 (remainder)	$ 20,411
2021	20,391
2022	19,498
2023	19,023
2024	18,718
Thereafter	$ 16,280

Computation of Basic and Dilute

Computation of Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
Net Income Loss Per Common Share
Net income for basic and diluted net income per share		$ 176,191	$ 109,138
Weighted average common shares-basic		166,589	173,532
Incremental shares from assumed conversion of convertible notes	[1]	7,333	2,186
Convertible note hedge warrant shares	[2]	5,492
Employee stock purchase plan		25	11
Dilutive potential common shares		14,147	3,440
Weighted average common shares-diluted		180,736	176,972
Net income per common share-basic		$ 1.06	$ 0.63
Net income per common share-diluted		$ 0.97	$ 0.62
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		1,163	1,021
Stock Options
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		134	222
[1]	Incremental shares from assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.61, multiplied by 14.6 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 notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.66, multiplied by 14.6 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 Income Per Common Share (Parenthetical) (Detail) shares in Millions	3 Months Ended
	Mar. 29, 2020$ / sharesshares
Convertible Notes
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 31.61
Shares that would be issued upon conversion | shares	14.6
Convertible Notes Hedge Warrant
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 39.66
Shares that would be issued upon conversion | shares	14.6

Net Income Per Common Share - A

Net Income Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Net Income Loss Per Common Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.3	0.6

Restructuring and Other - Addit

Restructuring and Other - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Restructuring Cost and Reserve
Contingent consideration adjustment	$ (10,020)	$ 2,970
Semiconductor Test
Restructuring Cost and Reserve
Contingent consideration adjustment	10,000	3,000
Severance benefit and charges	1,400	1,300
Impairment charges fixed assets	$ 700	$ 800

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 29, 2020USD ($)
United States Plans
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 0.7
U.S. Supplemental Executive Defined Benefit Pension Plan
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	$ 0.2

Schedule of Net Periodic Pensio

Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
UNITED STATES
Defined Benefit Plan Disclosure
Service cost	$ 433	$ 405
Interest cost	1,522	1,795
Expected return on plan assets	(1,233)	(1,511)
Total net periodic pension cost	722	689
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	201	188
Interest cost	115	173
Expected return on plan assets	(15)	(7)
Total net periodic pension cost	301	354
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	11	9
Interest cost	62	85
Amortization of prior service cost	(2)	(48)
Total net periodic pension cost	$ 71	$ 46

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Mar. 29, 2020USD ($)
Purchase Commitment, Excluding Long-term Commitment
Aggregate purchase commitments	$ 543.8
Purchase commitments less than one year	$ 529.4

Schedule of Reconciliation of E

Schedule of Reconciliation of Effective Tax Rate (Detail)	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Income Tax Disclosure [Line Items]
US statutory federal tax rate	21.00%	21.00%
Foreign taxes	(5.70%)	(3.10%)
Tax credits	(1.90%)	(3.00%)
Discrete benefit related to equity compensation	(4.10%)	(4.10%)
Discrete benefit related to release of reserves for uncertain tax positions	0.00%	(27.60%)
Other, net	1.30%	0.70%
Effective tax rate	10.60%	(16.10%)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Dec. 31, 2019
Income Taxes [Line Items]
Tax savings due to the tax holiday	$ 7.1	$ 2.1
Tax savings due to the tax holiday, per share	$ 0.04	$ 0.01
Accrued interest and penalties	$ 1.6		$ 1.4
Interest and penalties related to income tax, expense (benefit)	0.1	$ 0.3
Uncertain tax positions	21.3		$ 21.2
Net increase in reserves for uncertain tax positions	$ 0.1

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 29, 2020Segment
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
		Mar. 29, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	[1]	$ 704,355	$ 494,099
Income (loss) before taxes		197,069	93,979
Total assets		2,820,388	2,616,643	$ 2,787,014
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		484,489	340,853
Income (loss) before taxes		153,816	83,049
Total assets		921,108	770,967
System Test
Segment Reporting Information [Line Items]
Revenues	[1]	116,076	58,220
Income (loss) before taxes		48,407	15,340
Total assets		137,056	98,916
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		60,305	66,136
Income (loss) before taxes		(15,335)	(5,295)
Total assets		643,011	596,899
Wireless Test
Segment Reporting Information [Line Items]
Revenues	[1]	43,485	29,041
Income (loss) before taxes		10,220	3,628
Total assets		106,400	73,066
Corporate And Others [Member]
Segment Reporting Information [Line Items]
Revenues		0	(151)
Income (loss) before taxes		(39)	(2,743)
Total assets		$ 1,012,813	$ 1,076,795
[1]	Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.

Schedule of Segment Reporting I

Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Contingent consideration adjustment	$ (10,020)	$ 2,970
Universal Robots (UR)
Segment Reporting Information [Line Items]
Contingent consideration adjustment		3,800
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	3,026	1,174
Contingent consideration adjustment	10,000	3,000
Industrial Automation
Segment Reporting Information [Line Items]
Acquisition related costs	618	1,261
Corporate And Eliminations | Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs	741	0
Corporate And Eliminations | Universal Robots (UR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment	(7,142)	0
Corporate And Eliminations | Mobile Industrial Robots (MiR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment	$ (2,878)	$ 3,003

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Cumulative repurchases, shares	1.3	4.5
Common stock average price	$ 58.81	$ 35.12
Dividends Payable, Amount Per Share			$ 0.10	$ 0.09
Dividend payment	$ 16,686	$ 15,627
Share Repurchase Program [Member]
Cumulative repurchases, value	79,000	$ 156,500
Maximum [Member]
Stock repurchase program, authorized amount	$ 1,000,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event $ in Millions	May 01, 2020USD ($)
Subsequent Event [Line Items]
Term of loan, years	3 years
Line of Credit Facility, Maximum Borrowing Capacity	$ 400
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	$ 150
Line of Credit Facility, Interest Rate Description	The interest rates applicable to loans under the Credit Facility are, at Teradyne’s option, equal to either a base rate plus a margin ranging from 0.50% to 1.25% per annum or LIBOR, a minimum of 0.75%, plus a margin ranging from 1.50% to 2.25% per annum, based on the consolidated leverage ratio of Teradyne. In addition, Teradyne will pay a commitment fee on the unused portion of the commitments under the Credit Facility ranging from 0.25% to 0.40% per annum, based on the then applicable consolidated leverage ratio.
Collateral Pledged [Member]
Subsequent Event [Line Items]
Percent Of Available For Sale Securities Restricted	65.00%