Teradyne (TER) 10-Q 6 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jul. 04, 2021	Aug. 02, 2021
Cover [Abstract]
Amendment Flag	false
Document Type	10-Q
Document Fiscal Year Focus	2021
Entity Central Index Key	0000097210
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Document Period End Date	Jul. 4, 2021
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		164,973,199

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jul. 04, 2021		Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 954,441		$ 914,121
Marketable securities	282,121		522,280
Accounts receivable, less allowance for credit losses of $1,931 and $2,034 at July 4, 2021 and December 31, 2020, respectively	868,457		497,506
Inventories, net	226,138		222,189
Prepayments and other current assets	368,315		259,338
Total current assets	2,699,472		2,415,434
Property, plant and equipment, net	395,395		394,800
Operating lease right-of-use assets, net	61,849		54,569
Marketable securities	181,560		117,980
Deferred tax assets	94,438		87,913
Retirement plans assets	17,170		17,468
Other assets	21,320		9,384
Acquired intangible assets, net	88,121		100,939
Goodwill	441,597		453,859
Total assets	4,000,922	[1]	3,652,346
Current liabilities:
Accounts payable	156,103		133,663
Accrued employees' compensation and withholdings	205,717		220,321
Deferred revenue and customer advances	148,882		134,662
Other accrued liabilities	146,484		77,581
Operating lease liabilities	20,539		20,573
Income taxes payable	93,876		80,728
Current debt	213,761		33,343
Total current liabilities	985,362		700,871
Retirement plans liabilities	154,311		151,140
Long-term deferred revenue and customer advances	58,534		58,359
Long-term contingent consideration	0		7,227
Long-term other accrued liabilities	19,387		19,352
Deferred tax liabilities	8,961		10,821
Long-term operating lease liabilities	49,066		42,073
Long-term incomes taxes payable	67,041		74,930
Debt	143,618		376,768
Total liabilities	1,486,280		1,441,541
Commitments and contingencies
Mezzanine equity:
Convertible common shares	21,386		3,787
SHAREHOLDERS' EQUITY
Common stock, $0.125 par value, 1,000,000 shares authorized; 165,444 and 166,123 shares issued and outstanding at July 4, 2021 and December 31, 2020, respectively	20,680		20,765
Additional paid-in capital	1,772,302		1,765,323
Accumulated other comprehensive income	15,322		33,516
Retained earnings	684,952		387,414
Total shareholders' equity	2,493,256		2,207,018
Total liabilities, convertible common shares and shareholders' equity	$ 4,000,922		$ 3,652,346
[1]	Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Accounts receivable, less allowance for credit losses	$ 1,931	$ 2,034
Common stock, par value	$ 0.125	$ 0.125
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	165,444	166,123
Common stock, shares outstanding	165,444	166,123

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 04, 2021		Jun. 28, 2020		Jul. 04, 2021		Jun. 28, 2020
Revenues:
Total revenues	$ 1,085,728	[1]	$ 838,661	[1]	$ 1,867,334	[2]	$ 1,543,016	[2]
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	438,739		367,188		758,727		665,993
Gross profit	646,989		471,473		1,108,607		877,023
Operating expenses:
Selling and administrative	140,187		113,259		269,984		224,647
Engineering and development	110,021		94,102		210,423		179,261
Acquired intangible assets amortization	5,402		8,941		10,938		18,832
Restructuring and other	2,507		37,222		(4,623)		29,616
Total operating expenses	258,117		253,524		486,722		452,356
Income from operations	388,872		217,949		621,885		424,667
Non-operating (income) expense:
Interest income	(633)		(1,368)		(1,441)		(4,119)
Interest expense	5,566		6,043		11,569		11,594
Other (income) expense, net	(87)		(4,017)		3,738		2,833
Income before income taxes	384,026		217,291		608,019		414,359
Income tax provision	55,707		28,383		74,188		49,261
Net income	$ 328,319		$ 188,908		$ 533,831		$ 365,098
Net income per common share:
Basic	$ 1.98		$ 1.14		$ 3.21		$ 2.20
Diluted	$ 1.76		$ 1.05		$ 2.85		$ 2.02
Weighted average common shares—basic	165,995		165,789		166,243		166,189
Weighted average common shares—diluted	186,750		180,257		187,245		180,497
Cash dividend declared per common share	$ 0.10		$ 0.10		$ 0.20		$ 0.20
Product [Member]
Revenues:
Total revenues	$ 951,945		$ 734,630		$ 1,612,453		$ 1,345,536
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	388,845		322,732		656,629		582,728
Service [Member]
Revenues:
Total revenues	133,783		104,031		254,881		197,480
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	$ 49,894		$ 44,456		$ 102,098		$ 83,265
[1]	Includes $4.2 million and $2.5 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.”
[2]	Includes $7.3 million and $4.3 million in 2021 and 2020, respectively, 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		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Net income	$ 328,319	$ 188,908	$ 533,831	$ 365,098
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax of $0, $0, $0, $0, respectively	5,150	15,805	(15,974)	7,026
Available-for-sale marketable securities:
Unrealized gains (losses) on marketable securities arising during period, net of tax of $436, $1,084, $(472), $1,271, respectively	1,494	3,793	(1,776)	4,830
Less: Reclassification adjustment for losses (gains) included in net income, net of tax of $2, $(277), $(121), $(421), respectively	3	(983)	(441)	(1,499)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	1,497	2,810	(2,217)	3,331
Defined benefit post-retirement plan:
Amortization of prior service credit, net of tax of $0, $0, $(1), $(1), respectively	(2)	(2)	(3)	(3)
Other comprehensive income (loss)	6,645	18,613	(18,194)	10,354
Comprehensive income	$ 334,964	$ 207,521	$ 515,637	$ 375,452

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Foreign currency translation adjustment, net of tax	$ 0	$ 0	$ 0	$ 0
Unrealized gains (losses) on marketable securities arising during period	436	1,084	(472)	1,271
Reclassification adjustment for losses (gains) included in net income	2	(277)	(121)	(421)
Amortization of prior service credit, net of tax	$ 0	$ 0	$ (1)	$ (1)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE COMMON SHARES AND SHAREHOLDERS'' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Convertible Common Shares	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)
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	(10,382)		$ 114	(10,496)
Net issuance of common stock under stock-based plans (in shares)			913
Stock-based compensation expense	21,083			21,083
Repurchase of common stock	$ (88,465)		$ (190)			(88,275)
Repurchase of common stock (in shares)	1,500		(1,517)
Cash dividends	$ (33,295)					(33,295)
Net income	365,098					365,098
Other comprehensive income	10,354				10,354
Balance at Jun. 28, 2020	1,744,551		$ 20,725	1,730,716	(8,500)	1,610
Balance, Shares at Jun. 28, 2020			165,806
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
Net issuance of common stock under stock-based plans	(446)		$ 5	(451)
Net issuance of common stock under stock-based plans (in shares)			41
Stock-based compensation expense	9,800			9,800
Repurchase of common stock	(6,401)		$ (22)			(6,379)
Repurchase of common stock (in shares)			(173)
Cash dividends	(16,596)					(16,596)
Net income	188,908					188,908
Other comprehensive income	18,613				18,613
Balance at Jun. 28, 2020	1,744,551		$ 20,725	1,730,716	(8,500)	1,610
Balance, Shares at Jun. 28, 2020			165,806
Balance at Dec. 31, 2020	2,207,018		$ 20,765	1,765,323	33,516	387,414
Balance, Shares at Dec. 31, 2020		3,787	166,123
Net issuance of common stock under stock-based plans	322		$ 111	211
Net issuance of common stock under stock-based plans (in shares)			885
Stock-based compensation expense	25,874			25,874
Repurchase of common stock	$ (203,184)		$ (196)			(202,988)
Repurchase of common stock (in shares)	1,600		(1,564)
Cash dividends	$ (33,305)					(33,305)
Settlements of convertible notes	203,706		$ 199	203,507
Settlement of convertible debt (in shares)			1,589
Exercise of convertible notes hedge call options	(205,213)		$ (199)	(205,014)
Exercise of convertible notes hedge call options (in shares)			(1,589)
Convertible common shares	(17,599)			(17,599)
Convertible common shares (in shares)		17,599
Net income	533,831					533,831
Other comprehensive income	(18,194)				(18,194)
Balance at Jul. 04, 2021	2,493,256		$ 20,680	1,772,302	15,322	684,952
Balance, Shares at Jul. 04, 2021		21,386	165,444
Balance at Apr. 04, 2021	2,324,553		$ 20,802	1,765,971	8,677	529,103
Balance, Shares at Apr. 04, 2021		1,233	166,419
Net issuance of common stock under stock-based plans	14,310		$ 27	14,283
Net issuance of common stock under stock-based plans (in shares)			215
Stock-based compensation expense	12,515			12,515
Repurchase of common stock	(155,995)		$ (149)			(155,846)
Repurchase of common stock (in shares)			(1,190)
Cash dividends	(16,624)					(16,624)
Settlements of convertible notes	46,023		$ 46	45,977
Settlement of convertible debt (in shares)			367
Exercise of convertible notes hedge call options	(46,337)		$ (46)	(46,291)
Exercise of convertible notes hedge call options (in shares)			(367)
Convertible common shares	(20,153)			(20,153)
Convertible common shares (in shares)		20,153
Net income	328,319					328,319
Other comprehensive income	6,645				6,645
Balance at Jul. 04, 2021	$ 2,493,256		$ 20,680	$ 1,772,302	$ 15,322	$ 684,952
Balance, Shares at Jul. 04, 2021		21,386	165,444

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE COMMON SHARES AND SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Common Stock, Dividends, Per Share, Cash Paid	$ 0.10	$ 0.10	$ 0.20	$ 0.20

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020
Cash flows from operating activities:
Net income	$ 533,831	$ 365,098
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Depreciation	45,848	38,305
Stock-based compensation	23,231	21,367
Amortization	19,343	26,234
Loss on convertible debt conversion	5,244
Provision for excess and obsolete inventory	3,625	9,637
Contingent consideration adjustment	(7,227)	19,239
Gains on investments	(4,650)	(469)
Deferred taxes	(800)	(7,163)
Retirement plans actuarial gains	(627)	(99)
Other	199	523
Changes in operating assets and liabilities, net of business acquired:
Accounts receivable	(372,698)	(331,040)
Inventories	19,908	(3,728)
Prepayments and other assets	(117,416)	(49,479)
Accounts payable and other liabilities	86,790	113,578
Deferred revenue and customer advances	15,189	28,655
Retirement plans contributions	(2,739)	(2,501)
Income taxes	(2,628)	37,842
Net cash provided by operating activities	244,423	265,999
Cash flows from investing activities:
Purchases of property, plant and equipment	(73,957)	(84,014)
Purchases of marketable securities	(398,086)	(299,548)
Proceeds from maturities of marketable securities	460,213	182,984
Proceeds from sales of marketable securities	116,112	26,661
Proceeds from life insurance		546
Purchase of investment and acquisition of businesses	(12,000)	149
Net cash provided by (used for) investing activities	92,282	(173,222)
Cash flows from financing activities:
Issuance of common stock under stock purchase and stock option plans	32,581	12,757
Repurchase of common stock	(196,584)	(88,465)
Payments of convertible debt principal	(66,828)
Dividend payments	(33,271)	(33,266)
Payments related to net settlement of employee stock compensation awards	(31,794)	(22,519)
Payments of contingent consideration		(8,852)
Net cash used for financing activities	(295,896)	(140,345)
Effects of exchange rate changes on cash and cash equivalents	(489)	(925)
Increase (decrease) in cash and cash equivalents	40,320	(48,493)
Cash and cash equivalents at beginning of period	914,121	773,924
Cash and cash equivalents at end of period	954,441	725,431
Non-cash investing activities:
Capital expenditures incurred but not yet paid	$ 4,503	$ 6,281

The Company

The Company	6 Months Ended
	Jul. 04, 2021
The Company	A. THE 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 many industries including 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, logistics and light industrial customers to improve quality, increase manufacturing and material handling efficiency and decrease manufacturing and logistics costs. Teradyne’s automatic test equipment and industrial automation products and services include: • semiconductor test (“Semiconductor Test”) systems; • storage and system level test (“Storage Test”) systems, defense/aerospace (“Defense/Aerospace”) test instrumentation and systems, and circuit-board test and inspection (“Production Board Test”) systems (collectively these products represent “System Test”); • wireless test (“Wireless Test”) systems; and • industrial automation (“Industrial Automation”) products.

Accounting Policies

Accounting Policies	6 Months Ended
	Jul. 04, 2021
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, 2020 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by United States of America generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 22, 2021, for the year ended December 31, 2020. 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 of assets, liabilities, revenues and expenses, and related disclosures of contingent liabilities. On an on-going basis, management evaluates its estimates, including those related to inventories, investments, goodwill, intangible and other long-lived assets, accounts receivable, income taxes, deferred tax assets and liabilities, pensions, warranties, contingent consideration liabilities, and loss contingencies. Management bases its estimates on historical experience and on appropriate and customary assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgements about the carrying values of assets and liabilities that are not readily apparent from other sources. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and our markets. Management 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 August 6

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	6 Months Ended
	Jul. 04, 2021
Recently Issued Accounting Pronouncements	C. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2020-06 – “Debt—Debt with Conversion and Other Options and Derivatives and Hedging - Contracts in Entity’s Own Equity,” which simplifies the accounting for convertible debt instruments by reducing the number of accounting models and the number of embedded conversion features that could be recognized separately from the primary contract. This ASU requires a convertible debt instrument to be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. This ASU requires an entity to use the if-converted method in the diluted earnings per share calculation for convertible instruments. This ASU will be effective for Teradyne on January 1, 2022. This ASU permits the use of either the modified retrospective or fully retrospective method of transition. Teradyne is evaluating the effects of the adoption of this ASU on its financial statements.

Investment In Other Company

Investment In Other Company	6 Months Ended
	Jul. 04, 2021
Equity Method Investments and Joint Ventures [Abstract]
Investment In Other Company	D. INVESTMENT IN OTHER COMPANY On June 1, 2021, Teradyne invested $12.0 million in MachineMetrics, Inc. (“MachineMetrics”), a private company that develops and sells products to improve manufacturing performance through automated machine data collection, alerting, and analytics. Teradyne’s investment in MachineMetrics aligns with its strategy of providing and investing in leading edge products for automating industrial production processes in growing markets. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer on a quarterly basis. At July 4, 2021, the value of the investment was $12.0 million, no change during the three months ended July 4, 2021.

Revenue

Revenue	6 Months Ended
	Jul. 04, 2021
Revenue from Contract with Customer [Abstract]
Revenue	E. 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 System on- a-Chip Memory System Test Universal Mobile AutoGuide Wireless Test Corporate and Other Total (in thousands) For the Three Months Ended July 4, 2021 (1) Timing of Revenue Recognition Point in Time $ 675,958 $ 84,232 $ 88,197 $ 74,412 $ 15,091 $ — $ 51,619 $ (146 ) $ 989,363 Over Time 65,712 8,074 16,622 1,665 809 209 3,274 — 96,365 Total $ 741,670 $ 92,306 $ 104,819 $ 76,077 $ 15,900 $ 209 $ 54,893 $ (146 ) $ 1,085,728 Geographical Market Asia Pacific $ 710,995 $ 87,151 $ 61,230 $ 18,044 $ 2,439 $ — $ 45,802 $ — $ 925,661 Americas 21,664 3,672 36,256 24,808 6,897 209 7,107 (146 ) 100,467 Europe, Middle East and Africa 9,011 1,483 7,333 33,225 6,564 — 1,984 — 59,600 Total $ 741,670 $ 92,306 $ 104,819 $ 76,077 $ 15,900 $ 209 $ 54,893 $ (146 ) $ 1,085,728 For the Three Months Ended June 28, 2020 (1) Timing of Revenue Recognition Point in Time $ 520,496 $ 80,032 $ 57,741 $ 41,804 $ 11,196 $ 3,408 $ 46,347 $ (253 ) $ 760,771 Over Time 54,077 4,542 14,065 1,747 76 545 2,838 — 77,890 Total $ 574,573 $ 84,574 $ 71,806 $ 43,551 $ 11,272 $ 3,953 $ 49,185 $ (253 ) $ 838,661 Geographical Market Asia Pacific $ 547,700 $ 82,492 $ 38,656 $ 14,279 $ 1,232 $ — $ 41,907 $ — $ 726,266 Americas 16,251 855 28,494 11,364 2,390 3,953 5,353 (253 ) 68,407 Europe, Middle East and Africa 10,622 1,227 4,656 17,908 7,650 — 1,925 — 43,988 Total $ 574,573 $ 84,574 $ 71,806 $ 43,551 $ 11,272 $ 3,953 $ 49,185 $ (253 ) $ 838,661 For the Six Months Ended July 4, 2021 (2) Timing of Revenue Recognition Point in Time $ 1,040,148 $ 186,124 $ 207,511 $ 138,419 $ 29,155 $ (120 ) $ 89,499 $ (289 ) $ 1,690,447 Over Time 121,752 14,015 30,145 3,259 876 548 6,292 — 176,887 Total $ 1,161,900 $ 200,139 $ 237,656 $ 141,678 $ 30,031 $ 428 $ 95,791 $ (289 ) $ 1,867,334 Geographical Market Asia Pacific $ 1,098,231 $ 191,200 $ 160,750 $ 35,877 $ 5,886 $ — $ 79,334 $ — $ 1,571,278 Americas 42,443 7,092 63,915 42,961 12,050 428 12,876 (289 ) 181,476 Europe, Middle East and Africa 21,226 1,847 12,991 62,840 12,095 — 3,581 — 114,580 Total $ 1,161,900 $ 200,139 $ 237,656 $ 141,678 $ 30,031 $ 428 $ 95,791 $ (289 ) $ 1,867,334 For the Six Months Ended June 28, 2020 (2) Timing of Revenue Recognition Point in Time $ 868,542 $ 159,429 $ 158,453 $ 89,306 $ 20,293 $ 4,532 $ 87,403 $ (253 ) $ 1,387,705 Over Time 106,171 9,494 29,429 3,942 117 891 5,267 — 155,311 Total $ 974,713 $ 168,923 $ 187,882 $ 93,248 $ 20,410 $ 5,423 $ 92,670 $ (253 ) $ 1,543,016 Geographical Market Asia Pacific $ 910,433 $ 158,601 $ 118,674 $ 25,195 $ 2,825 $ — $ 79,711 $ — $ 1,295,439 Americas 33,637 7,751 56,784 26,108 5,855 5,423 10,041 (253 ) 145,346 Europe, Middle East and Africa 30,643 2,571 12,424 41,945 11,730 — 2,918 — 102,231 Total $ 974,713 $ 168,923 $ 187,882 $ 93,248 $ 20,410 $ 5,423 $ 92,670 $ (253 ) $ 1,543,016 (1) Includes $4.2 million and $2.5 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.” (2) Includes $7.3 million and $4.3 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside ASC 606 “ Revenue from Contracts with Customers Contract Balances During the three and six months ended July 4, 2021, Teradyne recognized $22.0 million and $49.6 million, respectively, that was previously included within the deferred revenue and customer advances balances at the beginning of the period . During the three and six months ended June 28, 2020, Teradyne recognized $21.1 million and $60.6 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. As of July 4, 2021, Teradyne has $1,276.0 million of unsatisfied performance obligations. Teradyne expects to recognize 94% of the remaining performance obligations in the next 12 months Accounts Receivable Teradyne sells certain trade accounts receivables on a non-recourse basis to third-party financial institutions pursuant to factoring agreements. Teradyne accounts for these transactions as sales of receivables and presents cash proceeds as cash provided by operating activities in the consolidated statements of cash flows. Total trade accounts receivable sold under the factoring agreements were $7.6 million and $50.0 million for the three months ended July 4, 2021 and June 28, 2020, respectively, and $14.9 million and $96.8 million for the six months ended July 4, 2021 and June 28, 2020, respectively. Factoring fees for the sales of receivables were recorded in interest expense and were not material.

Inventories

Inventories	6 Months Ended
	Jul. 04, 2021
Inventories	F. INVENTORIES Inventories, net consisted of the following at July 4, 2021 and December 31, 2020: July 4, December 31, (in thousands) Raw material $ 117,339 $ 114,133 Work-in-process 37,884 25,408 Finished goods 70,915 82,648 $ 226,138 $ 222,189 Inventory reserves at July 4, 2021 and December 31, 2020 were $106.9 million and $110.6 million, respectively.

Financial Instruments

Financial Instruments	6 Months Ended
	Jul. 04, 2021
Financial Instruments	G. FINANCIAL INSTRUMENTS Cash Equivalents Teradyne considers all highly liquid investments with maturities of three months or less at the date of acquisition to be cash equivalents. Marketable Securities Teradyne’s available-for-sale debt securities are classified as Level 2 and equity and debt mutual funds are classified as Level 1. Contingent consideration is classified as Level 3. The vast majority of Level 2 securities are fixed income securities priced by third party pricing vendors. These pricing vendors utilize the most recent observable market information in pricing these securities or, if specific prices are not available, use other observable inputs like market transactions involving identical or comparable securities. During the three and six months ended July 4, 2021 and June 28, 2020, there were no transfers in or out of Level 1, Level 2, or Level 3 financial instruments. Realized gains recorded in the three and six months ended July 4, 2021 were $0.9 million and $2.0 million, respectively. Realized gains recorded in the three and six months ended June 28, 2020 were $1.6 million and $3.0 million, respectively. Realized losses recorded in the three and six months ended June 28, 2020 were $0.1 million and $0.2 million, respectively. Realized gains and losses are included in other (income) expense, net. Unrealized gains on equity securities recorded in the three and six months ended July 4, 2021 were $2.0 million and $3.3 million, respectively. Unrealized losses on equity securities recorded in the three and six months ended July 4, 2021 were $0.7 million. Unrealized gains on equity securities recorded in the three and six months ended June 28, 2020 were $3.7 million. Unrealized losses on equity securities recorded in the six months ended June 28, 2020 were $6.0 million. Unrealized gains and losses on equity securities are included in other (income) expense, net. Unrealized gains and losses on available-for-sale debt securities are included in accumulated other comprehensive income (loss). The cost of securities sold is based on average cost. 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 July 4, 2021 and December 31, 2020. July 4, 2021 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 $ 568,630 $ — $ — $ 568,630 Cash equivalents 373,113 12,698 — 385,811 Available-for-sale securities: Commercial paper — 225,415 — 225,415 U.S. Treasury securities — 102,316 — 102,316 Corporate debt securities — 85,294 — 85,294 Debt mutual funds 8,030 — — 8,030 U.S. government agency securities — 4,508 — 4,508 Certificates of deposit and time deposits — 1,344 — 1,344 Non-U.S. government securities — 616 — 616 Equity securities: Mutual funds 36,158 — — 36,158 $ 985,931 $ 432,191 $ — $ 1,418,122 Derivative assets — 25 — 25 Total $ 985,931 $ 432,216 $ — $ 1,418,147 Liabilities Derivative liabilities — 365 — 365 Total $ — $ 365 $ — $ 365 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 941,743 $ 12,698 $ — $ 954,441 Marketable securities — 282,121 — 282,121 Long-term marketable securities 44,188 137,372 — 181,560 Prepayments and other current assets — 25 — 25 Total $ 985,931 $ 432,216 $ — $ 1,418,147 Liabilities Other current liabilities $ — $ 365 $ — $ 365 Total $ — $ 365 $ — $ 365 December 31, 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 $ 443,166 $ — $ — $ 443,166 Cash equivalents 347,768 123,187 — 470,955 Available-for-sale securities: — U.S. Treasury securities — 258,304 — 258,304 Commercial paper — 254,413 — 254,413 Corporate debt securities — 83,615 — 83,615 Debt mutual funds 8,565 — — 8,565 U.S. government agency securities — 4,339 — 4,339 Certificates of deposit and time deposits — 979 — 979 Non-U.S. government securities — 625 — 625 Equity securities: Equity mutual funds 29,420 — — 29,420 $ 828,919 $ 725,462 $ — $ 1,554,381 Derivative assets — 95 — 95 Total $ 828,919 $ 725,557 $ — $ 1,554,476 Liabilities Contingent consideration $ — $ — $ 7,227 $ 7,227 Derivative liabilities — 504 — 504 Total $ — $ 504 $ 7,227 $ 7,731 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 790,934 $ 123,187 $ — $ 914,121 Marketable securities — 522,280 — 522,280 Long-term marketable securities 37,985 79,995 — 117,980 Prepayments and other current assets — 95 — 95 Total $ 828,919 $ 725,557 $ — $ 1,554,476 Liabilities Other accrued liabilities $ — $ 504 $ — $ 504 Long-term contingent consideration — — 7,227 7,227 Total $ — $ 504 $ 7,227 $ 7,731 Changes in the fair value of Level 3 contingent consideration for the three months ended July 4, 2021 and June 28, 2020 were as follows: For the Three Months Ended For the Six Months Ended July 4, June 28, July 4, June 28, (in thousands) Balance at beginning of period $ — $ 20,472 $ 7,227 $ 39,705 Fair value adjustment (a)(b) — 29,259 (7,227 ) 19,239 Foreign currency impact — 6 — (355 ) Payments (c) — — — (8,852 ) Balance at end of period $ — $ 49,737 $ — $ 49,737 (a) In the six months ended July 4, 2021, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide was reduced to zero, which resulted in a benefit of $7.2 million, primarily due to a decrease in forecasted revenues and earnings before interest and taxes. As of July 4, 2021, the maximum amount of contingent consideration that could be paid in connection with the acquisition of AutoGuide is $100.2 million. The remaining earn-out periods end on December 31, 2021 and December 31, 2022. The sellers of AutoGuide have filed an arbitration claim against Teradyne related to allegations of non-compliance with its earn-out obligations. The ultimate amount of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide may be affected by the outcome of the arbitration (see Note R: “Commitments and Contingencies”). (b) In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of Mobile Industrial Robots (“MiR”) decreased by $0.6 million and $3.6 million, respectively, due to lower forecasted results. In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide increased by $29.9 million and $22.8 million, respectively, due to higher forecasted results. (c) In the six months ended June 28, 2020, Teradyne paid $8.9 million of contingent consideration for the earn-out in connection with the acquisition of MiR. The carrying amounts and fair values of Teradyne’s financial instruments at July 4, 2021 and December 31, 2020 were as follows: July 4, 2021 December 31, 2020 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 954,441 $ 954,441 $ 914,121 $ 914,121 Marketable securities 463,681 463,681 640,260 640,260 Derivative assets 25 25 95 95 Liabilities Contingent consideration — — 7,227 7,227 Derivative liabilities 365 365 504 504 Convertible debt (1) 357,379 1,595,912 410,111 1,739,553 (1) The carrying value represents the bifurcated debt component only, while the level 2 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 marketable securities at July 4, 2021: July 4, 2021 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Commercial paper $ 225,409 $ 7 $ (1 ) $ 225,415 $ 19,194 U.S. Treasury securities 102,068 767 (519 ) 102,316 72,750 Corporate debt securities 79,586 5,814 (106 ) 85,294 38,694 Debt mutual funds 7,956 74 — 8,030 — U.S. government agency securities 4,490 22 (4 ) 4,508 1,308 Certificates of deposit and time deposits 1,344 — — 1,344 — Non-U.S. government securities 616 — — 616 — $ 421,469 $ 6,684 $ (630 ) $ 427,523 $ 131,946 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 282,061 $ 93 $ (33 ) $ 282,121 $ 59,990 Long-term marketable securities 139,408 6,591 (597 ) 145,402 71,956 $ 421,469 $ 6,684 $ (630 ) $ 427,523 $ 131,946 The following table summarizes the composition of available-for-sale marketable securities at December 31, 2020: December 31, 2020 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 257,132 $ 1,330 $ (158 ) $ 258,304 $ 17,243 Commercial paper 254,404 10 (1 ) 254,413 12,173 Corporate debt securities 76,129 7,539 (53 ) 83,615 39,896 Debt mutual funds 8,413 152 — 8,565 — U.S. government agency securities 4,294 46 (1 ) 4,339 1,106 Certificates of deposit and time deposits 979 — — 979 — Non-U.S. government securities 625 — — 625 — $ 601,976 $ 9,077 $ (213 ) $ 610,840 $ 70,418 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 522,228 $ 92 $ (40 ) $ 522,280 $ 61,806 Long-term marketable securities 79,748 8,985 (173 ) 88,560 8,612 $ 601,976 $ 9,077 $ (213 ) $ 610,840 $ 70,418 As of July 4, 2021 and December 31, 2020, the fair market value of investments with unrealized losses less than one year totaled $130.7 million and $70.4 million, respectively. As of July 4, 2021, the fair market value of investments with unrealized losses for greater than one year totaled $1.3 million. 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 July 4, 2021 and December 31, 2020 were not other than temporary. The contractual maturities of investments in available-for-sale securities held at July 4, 2021 were as follows: July 4, 2021 Cost Fair Market Value (in thousands) Due within one year $ 282,061 $ 282,121 Due after 1 year through 5 years 90,625 90,940 Due after 5 years through 10 years 6,089 6,585 Due after 10 years 34,738 39,847 Total $ 413,513 $ 419,493 Contractual maturities of investments in available-for-sale securities held at July 4, 2021 exclude debt mutual funds with a fair market value of $8.0 million, as they do not have a contractual maturity date. 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 July 4, 2021 and December 31, 2020 was $206.9 million and $152.9 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 July 4, 2021 and December 31, 2020: Balance Sheet Location July 4, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 25 $ 95 Foreign exchange contracts Other current liabilities (365 ) (504 ) Total derivatives $ (340 ) $ (409 ) The following table summarizes the effect of derivative instruments recognized in the statement of operations for the three and six months ended July 4, 2021 and June 28, 2020: Location of Losses (Gains) Recognized in Statement of Operations For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, July 4, June 28, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 1,531 $ 470 $ 3,650 $ 4,481 (1) The table does not reflect the corresponding gains and losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. (2) For the three and six months ended July 4, 2021, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.1 million and $0.3 million, respectively. (3) For the three months ended June 28, 2020, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.4 million. For the six months ended June 28, 2020, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.6 million. See Note H: “Debt” regarding derivatives related to the convertible senior notes.

Debt

Debt	6 Months Ended
	Jul. 04, 2021
Debt	H. DEBT 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 per year payable semiannually in arrears on June 15 September 15, 2023 five 6 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 $31.54. The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, approximately 12.5 million shares of Teradyne’s common stock. Separately and concurrent with the pricing of the Notes, Teradyne entered into warrant transactions with the Option Counterparties (the “Warrant Transactions”) in which it sold net-share-settled (or, at its election subject to certain conditions, cash-settled) warrants to the Option Counterparties. The Warrant Transactions currently cover, subject to customary anti-dilution adjustments, approximately 14.6 million shares of common stock. As of July 4, 2021, the strike price of the warrants was approximately $39.58 per share. The strike price is subject to adjustment under certain circumstances. The Warrant Transactions could have a dilutive effect to Teradyne’s common stock to the extent that the market price per share of Teradyne’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,” equity in its statements of financial position. The convertible note hedge is considered indexed to Teradyne’s common stock as the terms of the Note Hedge Transactions do not contain an exercise contingency and the settlement amount equals the difference between the fair value of a fixed number of Teradyne’s shares and a fixed strike price. Because the only variable that can affect the settlement amount is Teradyne’s stock price, which is an input to the fair value of a fixed-for-fixed option contract, the convertible note hedge is considered indexed to Teradyne’s common stock. Teradyne assessed whether the convertible note hedge should be classified as equity under ASC 815-40. In the Note Hedge Transactions contract the settlement terms permit net cash settlement or net share settlement, at the option of Teradyne. Therefore, the criteria as set forth in ASC 815-40 were evaluated by Teradyne. In reviewing the criteria, Teradyne noted the following: (1) the convertible note hedge does not require Teradyne to issue shares; (2) there is no requirement to net cash settle the convertible note hedge for failure to make timely filings with the SEC; (3) in the case of termination, the convertible note hedge is settled in the same consideration as the holders of the underlying stock; (4) the counterparty does not have rights that rank higher than those of a shareholder of the stock underlying the convertible note hedge; and (5) there is no requirement to post collateral. Based on its analysis of those criteria, Teradyne concluded that the convertible note hedge should be recorded in equity and no further adjustment should be made in future periods to adjust the value of the convertible note hedge. Teradyne analyzed the Warrant Transactions under ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” The provisions of ASC 470-20, “ Debt with Conversion and Other Options, seven-year The below tables represent the key components of Teradyne’s convertible senior notes: July 4, 2021 December 31, 2020 (in thousands) Debt principal $ 393,142 $ 459,971 Unamortized discount 35,763 49,860 Net carrying amount of convertible debt $ 357,379 $ 410,111 Reported as follows: July 4, 2021 December 31, (in thousands) Current debt $ 213,761 $ 33,343 Long-term debt 143,618 376,768 Net carrying amount of convertible debt $ 357,379 $ 410,111 For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Contractual interest expense on the coupon $ 1,072 $ 1,438 $ 2,311 $ 2,875 Amortization of the discount component and debt issue fees recognized as interest expense 3,511 3,839 7,347 7,631 Total interest expense on the convertible debt $ 4,583 $ 5,277 $ 9,658 $ 10,506 As of July 4, 2021, the remaining unamortized discount was $35.8 million, which will be amortized over 2.5 years using the effective interest rate method. The carrying amount of the equity component was $100.8 million. As of July 4, 2021, the conversion price was approximately $31.54 per share and the if-converted value of the notes was $1,602.2 million. During the six months ended July 4, 2021, certain debt holders elected to convert $66.8 million of debt principal. The conversion of the debt was settled in cash for principal amount and in shares for the excess of conversion value over principal amount. The 1.6 million shares issued to the debt holders were received from exercising the convertible notes hedge call options. Additional conversions of approximately $235.2 million of debt principal will occur in the third quarter of 2021. The liability component is included in current debt and the equity component is included in convertible common shares. Revolving Credit Facility 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-year, senior secured revolving credit facility of $400.0 million (the “Credit Facility”). The Credit Agreement further provides that, subject to customary conditions, Teradyne may seek to obtain from existing or new lenders incremental commitments under the Credit Facility in an aggregate principal amount not to exceed $150.0 million. Proceeds from the Credit Facility may be used for general corporate purposes and working capital. Teradyne incurred $3.5 million in costs related to the revolving credit facility. These costs are being amortized over the three-year term of the revolving credit facility and are included in interest expense in the statement of operations. As of August 6 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. As of August 6

Prepayments

Prepayments	6 Months Ended
	Jul. 04, 2021
Prepayments [Abstract]
Prepayments	I. PREPAYMENTS Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: July 4, 2021 December 31, 2020 (in thousands) Contract manufacturer and supplier prepayments $ 320,111 $ 212,286 Prepaid maintenance and other services 16,848 13,116 Prepaid taxes 13,017 9,361 Other prepayments 9,434 15,329 Total prepayments $ 359,410 $ 250,092

Deferred Revenue and Customer A

Deferred Revenue and Customer Advances	6 Months Ended
	Jul. 04, 2021
Deferred Revenue and Customer Advances	J. 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: July 4, 2021 December 31, 2020 (in thousands) Maintenance, service and training $ 83,557 $ 77,654 Extended warranty 63,525 51,929 Customer advances, undelivered elements and other 60,334 63,438 Total deferred revenue and customer advances $ 207,416 $ 193,021

Product Warranty

Product Warranty	6 Months Ended
	Jul. 04, 2021
Product Warranties Disclosures [Abstract]
Product Warranty	K. PRODUCT WARRANTY Teradyne generally provides a one-year warranty on its products, commencing upon installation, acceptance or shipment. A provision is recorded upon revenue recognition to cost of revenues for estimated warranty expense based on historical experience. Related costs are charged to the warranty accrual as incurred. The balance below is included in other accrued liabilities. For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Balance at beginning of period $ 23,893 $ 10,971 $ 16,633 $ 8,996 Accruals for warranties issued during the period 10,197 6,200 22,078 11,267 Accruals related to pre-existing warranties (3,450 ) 356 (3,003 ) 1,412 Settlements made during the period (4,964 ) (4,511 ) (10,032 ) (8,659 ) Balance at end of period $ 25,676 $ 13,016 $ 25,676 $ 13,016 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 For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Balance at beginning of period $ 53,908 $ 33,503 $ 51,929 $ 30,677 Deferral of new extended warranty revenue 16,290 11,450 23,805 19,050 Recognition of extended warranty deferred revenue (6,673 ) (4,775 ) (12,209 ) (9,549 ) Balance at end of period $ 63,525 $ 40,178 $ 63,525 $ 40,178

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jul. 04, 2021
Stock-Based Compensation	L. STOCK-BASED COMPENSATION 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-based restricted stock unit awards granted to employees vest in equal annual installments over four years one-year annual meeting of shareholders. Teradyne expenses the cost of the restricted stock unit awards subject to service-based vesting, which is determined to be the fair market value of the shares at the date of grant, ratably over the period during which the restrictions lapse. Performance-based restricted stock units (“PRSUs”) granted to Teradyne’s executive officers may have a performance metric based on relative total shareholder return (“TSR”). Teradyne’s three-year line basis over the shorter of the three-year three-year 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 Teradyne’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 0% to 200% 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 year 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 six ten years Stock options to purchase Teradyne’s common stock at 100% of the fair market value on the grant date vest in equal annual installments over four years from the grant date and have a maximum term of seven years. During the six months ended July 4, 2021 and June 28, 2020, Teradyne granted 0.3 million and 0.4 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $113.23 and $70.52, respectively, and 0.1 127.77 64.99 During the six months ended July 4, 2021 and June 28, 2020, Teradyne granted 0.1 million of PBIT PRSUs with a grant date fair value of $113.65 and $70.94, respectively. During the six months ended July 4, 2021 and June 28, 2020, Teradyne granted 0.1 million of TSR PRSUs, with a grant date fair value of $125.02 and $89.93, respectively. The fair value was estimated using the Monte Carlo simulation model with the following assumptions: For the Six Months Ended July 4, 2021 June 28, 2020 Risk-free interest rate 0.2% 1.5% Teradyne volatility-historical 43.9% 34.9% NYSE Composite Index volatility-historical 22.9% 11.4% Dividend yield 0.4% 0.6% Expected volatility was based on the historical volatility of Teradyne’s stock and the NYSE Composite Index over the most recent three-year period. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.40 per share divided by Teradyne’s stock price on the grant date of $113.48 for the 2021 grant and an estimated annual dividend amount of $0.40 per share divided by Teradyne’s stock price on the grant date of $72.10 for the 2020 grant. During the six months ended July 4, 2021 and June 28, 2020, Teradyne granted 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $36.60 and $20.67, respectively. The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Six Months Ended July 4, 2021 June 28, 2020 Expected life (years) 5.0 5.0 Risk-free interest rate 0.4% 1.6% Volatility-historical 37.8% 31.6% Dividend yield 0.4% 0.6% 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 $113.48 for the 2021 grant and an estimated annual dividend amount of $0.40 per share divided by Teradyne’s stock price on the grant date of $72.10 for the 2020 grant.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jul. 04, 2021
Accumulated Other Comprehensive Income (Loss)	M. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Changes in accumulated other comprehensive income (loss), which are presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended July 4, 2021 Balance at December 31, 2020, net of tax of $0, $1,910, $(1,126), respectively $ 25,389 $ 6,954 $ 1,173 $ 33,516 Other comprehensive loss before reclassifications, net of tax of $0, $(472), $0, respectively (15,974 ) (1,776 ) — (17,750 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(121), $(1), respectively — (441 ) (3 ) (444 ) Net current period other comprehensive loss, net of tax of $0, $(593), $(1), respectively (15,974 ) (2,217 ) (3 ) (18,194 ) Balance at July 4, 2021, net of tax of $0, $1,317, $(1,127), respectively $ 9,415 $ 4,737 $ 1,170 $ 15,322 Six Months Ended June 28, 2020 Balance at December 31, 2019, net of tax of $0, $946, $(1,124), respectively $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) Other comprehensive income before reclassifications, net of tax of $0, $1,271, $0, respectively 7,026 4,830 — 11,856 Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(421), $(1), respectively — (1,499 ) (3 ) (1,502 ) Net current period other comprehensive income (loss), net of tax of $0, $850, $(1), respectively 7,026 3,331 (3 ) 10,354 Balance at June 28, 2020, net of tax of $0, $1,796, $(1,125), respectively $ (16,488 ) $ 6,811 $ 1,177 $ (8,500 ) Reclassifications out of accumulated other comprehensive income (loss) to the statement of operations for the three and six months ended July 4, 2021 and June 28, 2020 were as follows: Details about Accumulated Other Comprehensive Income (Loss) Components For the Three Months Ended For the Six Months Ended Affected Line Item in the Statements of Operations July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Available-for-sale marketable securities: Unrealized (losses) gains, net of tax of $(2), $277, $121, $421, respectively $ (3 ) $ 983 $ 441 $ 1,499 Other (income) Defined benefit post-retirement plan: Amortization of prior service credit, net of tax of $0, $0, $1, $1, respectively 2 2 3 3 (a) Total reclassifications, net of tax of $(2), $277, $122, $422, respectively $ (1 ) $ 985 $ 444 $ 1,502 Net income (a) The amortization of prior service credit is included in the computation of net periodic postretirement benefit cost. See Note Q: “Retirement Plans.”

Goodwill and Acquired Intangibl

Goodwill and Acquired Intangible Assets	6 Months Ended
	Jul. 04, 2021
Goodwill and Intangible Assets	N. 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 six months ended July 4, 2021, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2020 Goodwill $ 433,752 $ 158,699 $ 361,819 $ 262,155 $ 1,216,425 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 433,752 10,516 7,976 1,615 453,859 Foreign currency translation adjustment (12,191 ) — — (71 ) (12,262 ) Balance at July 4, 2021 Goodwill 421,561 158,699 361,819 262,084 1,204,163 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 421,561 $ 10,516 $ 7,976 $ 1,544 $ 441,597 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 Balance at July 4, 2021 (in thousands) Developed technology $ 272,547 $ (216,820 ) $ (2,779 ) $ 52,948 Customer relationships 57,739 (47,780 ) 191 10,150 Tradenames and trademarks 70,120 (45,187 ) 90 25,023 Total intangible assets $ 400,406 $ (309,787 ) $ (2,498 ) $ 88,121 Balance at December 31, 2020 Developed technology $ 272,547 $ (210,479 ) $ (1,610 ) $ 60,458 Customer relationships 66,239 (54,524 ) 305 12,020 Tradenames and trademarks 70,120 (42,344 ) 685 28,461 Total intangible assets $ 408,906 $ (307,347 ) $ (620 ) $ 100,939 Aggregate intangible asset amortization expense was $5.4 million and $10.9 million, respectively, for the three and six months ended July 4, 2021 and $8.9 million and $18.8 million, respectively, for the three and six months ended June 28, 2020. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2021(remainder) $ 10,636 2022 20,570 2023 20,084 2024 19,776 2025 11,756 Thereafter 5,299

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jul. 04, 2021
Net Income per Common Share	O. NET INCOME PER COMMON SHARE The following table sets forth the computation of basic and diluted net income per common share: For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 328,319 $ 188,908 $ 533,831 $ 365,098 Weighted average common shares-basic 165,995 165,789 166,243 166,189 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 9,578 7,599 9,944 7,466 Convertible note hedge warrant shares (2) 10,073 5,824 9,751 5,658 Restricted stock units 1,015 913 1,205 1,038 Stock options 78 132 93 133 Employee stock purchase plan 11 — 9 13 Dilutive potential common shares 20,755 14,468 21,002 14,308 Weighted average common shares-diluted 186,750 180,257 187,245 180,497 Net income per common share-basic $ 1.98 $ 1.14 $ 3.21 $ 2.20 Net income per common share-diluted $ 1.76 $ 1.05 $ 2.85 $ 2.02 (1) Incremental shares from assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.54, multiplied by 12.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.58, 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 and six months ended June 28, 2020 excludes the effect of the potential vesting of 0.1 million and 0.2 million, respectively, of restricted stock units because the effect would have been anti-dilutive.

Restructuring and Other

Restructuring and Other	6 Months Ended
	Jul. 04, 2021
Restructuring and Related Activities [Abstract]
Restructuring and Other	P. RESTRUCTURING AND OTHER During the three months ended July 4, 2021, Teradyne recorded a charge of $1.7 million for an increase in environmental and legal liabilities, $0.4 million of severance charges primarily in Industrial Automation and $0.4 million for other expenses. During the three months ended June 28, 2020, Teradyne recorded a charge of $29.9 million for the increase in the fair value of the AutoGuide contingent consideration liability, a $4.0 million contract termination settlement charge, $3.1 million of acquisition related compensation and expenses, and $0.8 million of other expenses, partially offset by a $0.6 million gain for the decrease in the fair value of the MiR contingent consideration liability. During the six months ended July 4, 2021, Teradyne recorded a gain of $7.2 million for the decrease in the fair value of the AutoGuide contingent consideration liability, partially offset by a charge of $1.7 million for an increase in environmental and legal liabilities, $0.6 million of severance charges primarily in Industrial Automation and $0.3 million for other expenses. During the six months ended June 28, 2020, Teradyne recorded a $22.8 million charge for the increase in the fair value of the AutoGuide contingent consideration liabilities, $4.5 million of acquisition related compensation and expenses, a $4.0 million contract termination settlement charge, $1.1 million of other expenses, and $0.8 million of severance charges primarily in Semiconductor Test, partially offset by a $3.6 million gain for the decrease in the fair value of the MiR contingent consideration liability.

Retirement Plans

Retirement Plans	6 Months Ended
	Jul. 04, 2021
Retirement Plans	Q. RETIREMENT PLANS ASC 715, “Compensation—Retirement Benefits” Defined Benefit Pension Plans Teradyne has defined benefit pension plans covering a portion of domestic employees and employees of certain non-U.S. subsidiaries. Benefits under these plans are based on employees’ years of service and compensation. Teradyne’s funding policy is to make contributions to these plans in accordance with local laws and to the extent that such contributions are tax deductible. The assets of the U.S. qualified pension plan consist primarily of fixed income and equity securities. In addition, Teradyne has unfunded qualified foreign plans as well as an unfunded supplemental executive defined benefit plan in the United States to provide retirement benefits in excess of levels allowed by the Employment Retirement Income Security Act (“ERISA”) and the Internal Revenue Code (“IRC”). In the six months ended July 4, 2021, and June 28, 2020, Teradyne contributed $1.7 million and $1.4 million, respectively, to the U.S. supplemental executive defined benefit pension plan and $0.5 million and $0.4 million, respectively to certain qualified pension plans for non-U.S. subsidiaries. For the three and six months ended July 4, 2021 and June 28, 2020, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended July 4, 2021 June 28, 2020 United States Foreign United States Foreign (in thousands) Service cost $ 452 $ 245 $ 433 $ 208 Interest cost 1,096 88 1,523 119 Expected return on plan assets (936 ) (17 ) (1,232 ) (15 ) Net actuarial (gain) loss (400 ) — 180 — Total net periodic pension cost $ 212 $ 316 $ 904 $ 312 For the Six Months Ended July 4, 2021 June 28, 2020 UnitedStates Foreign UnitedStates Foreign (in thousands) Service cost $ 905 $ 491 $ 866 $ 417 Interest cost 2,196 175 3,045 238 Expected return on plan assets (1,872 ) (33 ) (2,464 ) (31 ) Net actuarial (gain) loss (400 ) — 180 — Total net periodic pension cost $ 829 $ 633 $ 1,627 $ 624 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 and six months ended July 4, 2021 and June 28, 2020, Teradyne’s net periodic postretirement benefit credit was comprised of the following: For the Three Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Service cost $ 17 $ 17 $ 33 $ 28 Interest cost 41 58 85 120 Amortization of prior service credit (2 ) (2 ) (4 ) (4 ) Net actuarial gain (228 ) (279 ) (228 ) (279 ) Total net periodic postretirement benefit credit $ (172 ) $ (206 ) $ (114 ) $ (135 )

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jul. 04, 2021
Commitments and Contingencies	R. COMMITMENTS AND CONTINGENCIES Purchase Commitments As of July 4, 2021, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments covered by the agreements aggregate to approximately $770.0 million, of which $754.3 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. On March 8, 2021, Industrial Automation LLC submitted a demand for arbitration against Teradyne and AutoGuide in Wilmington, Delaware alleging that Teradyne and AutoGuide breached certain provisions of the Membership Interests Purchase Agreement (the “Purchase Agreement”), dated as of October 18, 2019, among Industrial Automation LLC, Teradyne and AutoGuide. The arbitration demand seeks full acceleration of the maximum earnout amount payable under the Purchase Agreement, or $106.9 million ,

Income Taxes

Income Taxes	6 Months Ended
	Jul. 04, 2021
Income Taxes	S. INCOME TAXES A reconciliation of the United States federal statutory corporate tax rate to Teradyne’s effective tax rate was as follows: For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 U.S. statutory federal tax rate 21.0 % 21.0 % 21.0 % 21.0 % Foreign taxes (4.3 ) (4.6 ) (4.5 ) (5.1 ) International provisions of the U.S. Tax Cuts and Jobs Act of 2017 (1.7 ) (1.9 ) (1.6 ) (1.1 ) Tax credits (1.2 ) (1.4 ) (1.2 ) (1.6 ) Discrete benefit related to equity compensation (0.2 ) (0.1 ) (2.4 ) (2.0 ) Other, net 0.9 0.1 0.9 0.7 Effective tax rate 14.5 % 13.1 % 12.2 % 11.9 % On a quarterly basis, Teradyne evaluates the realizability of the deferred tax assets by jurisdiction and assesses the need for a valuation allowance. As of July 4, 2021, Teradyne believes that it will ultimately realize the deferred tax assets recorded on the condensed consolidated balance sheet. However, should Teradyne believe that it is more-likely-than-not that the deferred tax assets would not be realized, the tax provision would increase in the period in which Teradyne determined that the realizability was not likely. Teradyne considers the probability of future taxable income and historical profitability, among other factors, in assessing the realizability of the deferred tax assets. As of July 4, 2021 and December 31, 2020, Teradyne had $16.6 million and $17.9 million, respectively, of reserves for uncertain tax positions. The $1.3 million net decrease in reserves for uncertain tax positions is primarily related to U.S. state research and development credits generated in prior years, as well as U.S. federal research and development credits generated in the current year. As of July 4, 2021, Teradyne estimates that it is reasonably possible that the balance of unrecognized tax benefits may decrease approximately $1.6 million in the next twelve months because of a lapse of statutes of limitation. The estimated decrease relates to loss carryforwards, research credits and U.S. manufacturing activities deductions. Teradyne recognizes interest and penalties related to income tax matters in income tax expense. As of July 4, 2021 and December 31, 2020, $1.4 million and $1.2 million, respectively, of interest and penalties were accrued for uncertain tax positions. For the six months ended July 4, 2021 and June 28, 2020, expense of $0.2 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 six months ended July 4, 2021 was $15.9 million, or $0.08 per diluted share. The tax savings due to the tax holiday for the six months ended June 28, 2020 was $13.6 million, or $0.08 per diluted share. In November 2020, Teradyne entered into an agreement with the Singapore Economic Development Board which extended its Singapore tax holiday under substantially similar terms to the agreement which expired on December 31, 2020. The new tax holiday is scheduled to expire on December 31, 2025.

Segment Information

Segment Information	6 Months Ended
	Jul. 04, 2021
Segment Reporting [Abstract]
Segment Information	T. SEGMENT INFORMATION Teradyne has four reportable segments (Semiconductor Test, System Test, Industrial Automation and Wireless Test). Each of the reportable segments is also an individual operating segment. 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 and system level 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. Each operating segment has a segment manager who is directly accountable to and maintains regular contact with Teradyne’s chief operating decision maker (Teradyne’s chief executive officer) to discuss operating activities, financial results, forecasts, and plans for the segment. Teradyne evaluates performance based on several factors, of which the primary financial measure is business segment income (loss) before income taxes. The accounting policies of the business segments in effect are described in Note B: “Accounting Policies” in Teradyne’s Annual Report on Form 10-K for the year ended December 31, 2020. Segment information for the three and six months ended July 4, 2021 and June 28, 2020 is as follows: Semiconductor Test System Test Industrial Automation Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended July 4, 2021 Revenues $ 833,976 $ 104,819 $ 92,186 $ 54,893 $ (146 ) $ 1,085,728 Income (loss) before income taxes (1)(2) 337,302 33,954 (9,837 ) 21,472 1,135 384,026 Total assets (3) 1,518,941 146,296 687,022 117,702 1,530,961 4,000,922 Three Months Ended June 28, 2020 Revenues $ 659,147 $ 71,806 $ 58,776 $ 49,185 $ (253 ) $ 838,661 Income (loss) before income taxes (1)(2) 228,787 19,193 (11,403 ) 14,482 (33,768 ) 217,291 Total assets (3) 1,192,355 126,164 662,103 108,066 1,160,501 3,249,189 Six Months Ended July 4, 2021 Revenues $ 1,362,039 $ 237,656 $ 172,137 $ 95,791 $ (289 ) $ 1,867,334 Income (loss) before income taxes (1)(2) 513,670 85,015 (22,804 ) 31,088 1,050 608,019 Total assets (3) 1,518,941 146,296 687,022 117,702 1,530,961 4,000,922 Six Months Ended June 28, 2020 Revenues $ 1,143,636 $ 187,882 $ 119,081 $ 92,670 $ (253 ) $ 1,543,016 Income (loss) before income taxes (1)(2) 382,603 67,600 (26,738 ) 24,702 (33,808 ) 414,359 Total assets (3) 1,192,355 126,164 662,103 108,066 1,160,501 3,249,189 (1) Included in Corporate and Other are: contingent consideration adjustments, loss on convertible debt conversions, interest income, interest expense, net foreign exchange gains (losses), pension, intercompany eliminations and acquisition related: (a) charges; (b) legal fees; (c) compensation. (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, loss on convertible debt conversions 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 For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Semiconductor Test: Cost of revenues - inventory charge $ — $ 3,799 $ 1,234 $ 6,825 Restructuring and other - c — 4,000 — 4,000 Industrial Automation: Restructuring and other - acquisition related expenses and compensation $ — $ — $ 550 $ 790 Cost of revenues - inventory charge — — 1,285 — Wireless: Cost of revenues - inventory charge $ — $ 1,582 $ 672 $ 2,155 Corporate and Other: Restructuring and other - other $ 1,700 $ 750 $ 1,846 $ 750 Other (income) expense, net - l 1,175 — 5,244 — Restructuring and other - AutoGuide contingent consideration adjustment — 29,927 (7,227 ) 22,785 Restructuring and other - acquisition related expenses and compensation — 2,974 (513 ) 3,715 Restructuring and other - MiR contingent consideration adjustment — (668 ) — (3,546 )

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jul. 04, 2021
Equity [Abstract]
Shareholders' Equity	U. SHAREHOLDERS’ EQUITY Stock Repurchase Program In January 2021, Teradyne’s Board of Directors cancelled the January 2020 repurchase program and approved a new repurchase program for up to $2.0 billion of common stock. Teradyne intends to repurchase a minimum of $600 million in 2021. During the six months ended July 4, 2021, Teradyne repurchased 1.6 million shares of common stock for $196.6 million at an average price of $125.69 per share. During the six months ended June 28, 2020, Teradyne repurchased 1.5 million shares of common stock for $88.5 million at an average price of $58.33 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 and May 2021 and 2020, Teradyne’s Board of Directors declared a quarterly cash dividend of $0.10 per share. Dividend payments for each of the three and six months ended July 4, 2021 and June 28, 2020 were $16.6 million and $33.3 million, respectively. While Teradyne declared a quarterly cash dividend and authorized a share repurchase program, it may reduce or eliminate the cash dividend or share repurchase program in the future. Future cash dividends and stock repurchases are subject to the discretion of Teradyne’s Board of Directors, which will consider, among other things, Teradyne’s earnings, capital requirements and financial condition.

Accounting Policies (Policies)

Accounting Policies (Policies)	6 Months Ended
	Jul. 04, 2021
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, 2020 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by United States of America generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 22, 2021, for the year ended December 31, 2020.
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 of assets, liabilities, revenues and expenses, and related disclosures of contingent liabilities. On an on-going basis, management evaluates its estimates, including those related to inventories, investments, goodwill, intangible and other long-lived assets, accounts receivable, income taxes, deferred tax assets and liabilities, pensions, warranties, contingent consideration liabilities, and loss contingencies. Management bases its estimates on historical experience and on appropriate and customary assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgements about the carrying values of assets and liabilities that are not readily apparent from other sources. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and our markets. Management 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 August 6

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jul. 04, 2021
Revenue from Contract with Customer [Abstract]
Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition	The following table provides information about disaggregated revenue by timing of revenue recognition, primary geographical market, and major product lines. Semiconductor Test Industrial Automation System on- a-Chip Memory System Test Universal Mobile AutoGuide Wireless Test Corporate and Other Total (in thousands) For the Three Months Ended July 4, 2021 (1) Timing of Revenue Recognition Point in Time $ 675,958 $ 84,232 $ 88,197 $ 74,412 $ 15,091 $ — $ 51,619 $ (146 ) $ 989,363 Over Time 65,712 8,074 16,622 1,665 809 209 3,274 — 96,365 Total $ 741,670 $ 92,306 $ 104,819 $ 76,077 $ 15,900 $ 209 $ 54,893 $ (146 ) $ 1,085,728 Geographical Market Asia Pacific $ 710,995 $ 87,151 $ 61,230 $ 18,044 $ 2,439 $ — $ 45,802 $ — $ 925,661 Americas 21,664 3,672 36,256 24,808 6,897 209 7,107 (146 ) 100,467 Europe, Middle East and Africa 9,011 1,483 7,333 33,225 6,564 — 1,984 — 59,600 Total $ 741,670 $ 92,306 $ 104,819 $ 76,077 $ 15,900 $ 209 $ 54,893 $ (146 ) $ 1,085,728 For the Three Months Ended June 28, 2020 (1) Timing of Revenue Recognition Point in Time $ 520,496 $ 80,032 $ 57,741 $ 41,804 $ 11,196 $ 3,408 $ 46,347 $ (253 ) $ 760,771 Over Time 54,077 4,542 14,065 1,747 76 545 2,838 — 77,890 Total $ 574,573 $ 84,574 $ 71,806 $ 43,551 $ 11,272 $ 3,953 $ 49,185 $ (253 ) $ 838,661 Geographical Market Asia Pacific $ 547,700 $ 82,492 $ 38,656 $ 14,279 $ 1,232 $ — $ 41,907 $ — $ 726,266 Americas 16,251 855 28,494 11,364 2,390 3,953 5,353 (253 ) 68,407 Europe, Middle East and Africa 10,622 1,227 4,656 17,908 7,650 — 1,925 — 43,988 Total $ 574,573 $ 84,574 $ 71,806 $ 43,551 $ 11,272 $ 3,953 $ 49,185 $ (253 ) $ 838,661 For the Six Months Ended July 4, 2021 (2) Timing of Revenue Recognition Point in Time $ 1,040,148 $ 186,124 $ 207,511 $ 138,419 $ 29,155 $ (120 ) $ 89,499 $ (289 ) $ 1,690,447 Over Time 121,752 14,015 30,145 3,259 876 548 6,292 — 176,887 Total $ 1,161,900 $ 200,139 $ 237,656 $ 141,678 $ 30,031 $ 428 $ 95,791 $ (289 ) $ 1,867,334 Geographical Market Asia Pacific $ 1,098,231 $ 191,200 $ 160,750 $ 35,877 $ 5,886 $ — $ 79,334 $ — $ 1,571,278 Americas 42,443 7,092 63,915 42,961 12,050 428 12,876 (289 ) 181,476 Europe, Middle East and Africa 21,226 1,847 12,991 62,840 12,095 — 3,581 — 114,580 Total $ 1,161,900 $ 200,139 $ 237,656 $ 141,678 $ 30,031 $ 428 $ 95,791 $ (289 ) $ 1,867,334 For the Six Months Ended June 28, 2020 (2) Timing of Revenue Recognition Point in Time $ 868,542 $ 159,429 $ 158,453 $ 89,306 $ 20,293 $ 4,532 $ 87,403 $ (253 ) $ 1,387,705 Over Time 106,171 9,494 29,429 3,942 117 891 5,267 — 155,311 Total $ 974,713 $ 168,923 $ 187,882 $ 93,248 $ 20,410 $ 5,423 $ 92,670 $ (253 ) $ 1,543,016 Geographical Market Asia Pacific $ 910,433 $ 158,601 $ 118,674 $ 25,195 $ 2,825 $ — $ 79,711 $ — $ 1,295,439 Americas 33,637 7,751 56,784 26,108 5,855 5,423 10,041 (253 ) 145,346 Europe, Middle East and Africa 30,643 2,571 12,424 41,945 11,730 — 2,918 — 102,231 Total $ 974,713 $ 168,923 $ 187,882 $ 93,248 $ 20,410 $ 5,423 $ 92,670 $ (253 ) $ 1,543,016 (1) Includes $4.2 million and $2.5 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.” (2) Includes $7.3 million and $4.3 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside ASC 606 “ Revenue from Contracts with Customers

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jul. 04, 2021
Composition of Inventories, Net	Inventories, net consisted of the following at July 4, 2021 and December 31, 2020: July 4, December 31, (in thousands) Raw material $ 117,339 $ 114,133 Work-in-process 37,884 25,408 Finished goods 70,915 82,648 $ 226,138 $ 222,189

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jul. 04, 2021
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 July 4, 2021 and December 31, 2020. July 4, 2021 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 $ 568,630 $ — $ — $ 568,630 Cash equivalents 373,113 12,698 — 385,811 Available-for-sale securities: Commercial paper — 225,415 — 225,415 U.S. Treasury securities — 102,316 — 102,316 Corporate debt securities — 85,294 — 85,294 Debt mutual funds 8,030 — — 8,030 U.S. government agency securities — 4,508 — 4,508 Certificates of deposit and time deposits — 1,344 — 1,344 Non-U.S. government securities — 616 — 616 Equity securities: Mutual funds 36,158 — — 36,158 $ 985,931 $ 432,191 $ — $ 1,418,122 Derivative assets — 25 — 25 Total $ 985,931 $ 432,216 $ — $ 1,418,147 Liabilities Derivative liabilities — 365 — 365 Total $ — $ 365 $ — $ 365 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 941,743 $ 12,698 $ — $ 954,441 Marketable securities — 282,121 — 282,121 Long-term marketable securities 44,188 137,372 — 181,560 Prepayments and other current assets — 25 — 25 Total $ 985,931 $ 432,216 $ — $ 1,418,147 Liabilities Other current liabilities $ — $ 365 $ — $ 365 Total $ — $ 365 $ — $ 365 December 31, 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 $ 443,166 $ — $ — $ 443,166 Cash equivalents 347,768 123,187 — 470,955 Available-for-sale securities: — U.S. Treasury securities — 258,304 — 258,304 Commercial paper — 254,413 — 254,413 Corporate debt securities — 83,615 — 83,615 Debt mutual funds 8,565 — — 8,565 U.S. government agency securities — 4,339 — 4,339 Certificates of deposit and time deposits — 979 — 979 Non-U.S. government securities — 625 — 625 Equity securities: Equity mutual funds 29,420 — — 29,420 $ 828,919 $ 725,462 $ — $ 1,554,381 Derivative assets — 95 — 95 Total $ 828,919 $ 725,557 $ — $ 1,554,476 Liabilities Contingent consideration $ — $ — $ 7,227 $ 7,227 Derivative liabilities — 504 — 504 Total $ — $ 504 $ 7,227 $ 7,731 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 790,934 $ 123,187 $ — $ 914,121 Marketable securities — 522,280 — 522,280 Long-term marketable securities 37,985 79,995 — 117,980 Prepayments and other current assets — 95 — 95 Total $ 828,919 $ 725,557 $ — $ 1,554,476 Liabilities Other accrued liabilities $ — $ 504 $ — $ 504 Long-term contingent consideration — — 7,227 7,227 Total $ — $ 504 $ 7,227 $ 7,731
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 July 4, 2021 and June 28, 2020 were as follows: For the Three Months Ended For the Six Months Ended July 4, June 28, July 4, June 28, (in thousands) Balance at beginning of period $ — $ 20,472 $ 7,227 $ 39,705 Fair value adjustment (a)(b) — 29,259 (7,227 ) 19,239 Foreign currency impact — 6 — (355 ) Payments (c) — — — (8,852 ) Balance at end of period $ — $ 49,737 $ — $ 49,737 (a) In the six months ended July 4, 2021, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide was reduced to zero, which resulted in a benefit of $7.2 million, primarily due to a decrease in forecasted revenues and earnings before interest and taxes. As of July 4, 2021, the maximum amount of contingent consideration that could be paid in connection with the acquisition of AutoGuide is $100.2 million. The remaining earn-out periods end on December 31, 2021 and December 31, 2022. The sellers of AutoGuide have filed an arbitration claim against Teradyne related to allegations of non-compliance with its earn-out obligations. The ultimate amount of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide may be affected by the outcome of the arbitration (see Note R: “Commitments and Contingencies”). (b) In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of Mobile Industrial Robots (“MiR”) decreased by $0.6 million and $3.6 million, respectively, due to lower forecasted results. In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide increased by $29.9 million and $22.8 million, respectively, due to higher forecasted results. (c) In the six months ended June 28, 2020, Teradyne paid $8.9 million of contingent consideration for the earn-out in connection with the acquisition of MiR.
Schedule of Carrying Amounts and Fair Values of Financial Instruments	The carrying amounts and fair values of Teradyne’s financial instruments at July 4, 2021 and December 31, 2020 were as follows: July 4, 2021 December 31, 2020 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 954,441 $ 954,441 $ 914,121 $ 914,121 Marketable securities 463,681 463,681 640,260 640,260 Derivative assets 25 25 95 95 Liabilities Contingent consideration — — 7,227 7,227 Derivative liabilities 365 365 504 504 Convertible debt (1) 357,379 1,595,912 410,111 1,739,553 (1) The carrying value represents the bifurcated debt component only, while the level 2 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 marketable securities at July 4, 2021: July 4, 2021 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Commercial paper $ 225,409 $ 7 $ (1 ) $ 225,415 $ 19,194 U.S. Treasury securities 102,068 767 (519 ) 102,316 72,750 Corporate debt securities 79,586 5,814 (106 ) 85,294 38,694 Debt mutual funds 7,956 74 — 8,030 — U.S. government agency securities 4,490 22 (4 ) 4,508 1,308 Certificates of deposit and time deposits 1,344 — — 1,344 — Non-U.S. government securities 616 — — 616 — $ 421,469 $ 6,684 $ (630 ) $ 427,523 $ 131,946 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 282,061 $ 93 $ (33 ) $ 282,121 $ 59,990 Long-term marketable securities 139,408 6,591 (597 ) 145,402 71,956 $ 421,469 $ 6,684 $ (630 ) $ 427,523 $ 131,946 The following table summarizes the composition of available-for-sale marketable securities at December 31, 2020: December 31, 2020 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 257,132 $ 1,330 $ (158 ) $ 258,304 $ 17,243 Commercial paper 254,404 10 (1 ) 254,413 12,173 Corporate debt securities 76,129 7,539 (53 ) 83,615 39,896 Debt mutual funds 8,413 152 — 8,565 — U.S. government agency securities 4,294 46 (1 ) 4,339 1,106 Certificates of deposit and time deposits 979 — — 979 — Non-U.S. government securities 625 — — 625 — $ 601,976 $ 9,077 $ (213 ) $ 610,840 $ 70,418 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 522,228 $ 92 $ (40 ) $ 522,280 $ 61,806 Long-term marketable securities 79,748 8,985 (173 ) 88,560 8,612 $ 601,976 $ 9,077 $ (213 ) $ 610,840 $ 70,418
Contractual Maturities of Investments Held	The contractual maturities of investments in available-for-sale securities held at July 4, 2021 were as follows: July 4, 2021 Cost Fair Market Value (in thousands) Due within one year $ 282,061 $ 282,121 Due after 1 year through 5 years 90,625 90,940 Due after 5 years through 10 years 6,089 6,585 Due after 10 years 34,738 39,847 Total $ 413,513 $ 419,493
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	The following table summarizes the fair value of derivative instruments as of July 4, 2021 and December 31, 2020: Balance Sheet Location July 4, December 31, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 25 $ 95 Foreign exchange contracts Other current liabilities (365 ) (504 ) Total derivatives $ (340 ) $ (409 )
Schedule of Effect of Derivative Instruments on Statement of Operations Recognized	The following table summarizes the effect of derivative instruments recognized in the statement of operations for the three and six months ended July 4, 2021 and June 28, 2020: Location of Losses (Gains) Recognized in Statement of Operations For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, July 4, June 28, (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 1,531 $ 470 $ 3,650 $ 4,481 (1) The table does not reflect the corresponding gains and losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. (2) For the three and six months ended July 4, 2021, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.1 million and $0.3 million, respectively. (3) For the three months ended June 28, 2020, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $0.4 million. For the six months ended June 28, 2020, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $1.6 million.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jul. 04, 2021
Components of Convertible Senior Notes	The below tables represent the key components of Teradyne’s convertible senior notes: July 4, 2021 December 31, 2020 (in thousands) Debt principal $ 393,142 $ 459,971 Unamortized discount 35,763 49,860 Net carrying amount of convertible debt $ 357,379 $ 410,111 Reported as follows: July 4, 2021 December 31, (in thousands) Current debt $ 213,761 $ 33,343 Long-term debt 143,618 376,768 Net carrying amount of convertible debt $ 357,379 $ 410,111 For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Contractual interest expense on the coupon $ 1,072 $ 1,438 $ 2,311 $ 2,875 Amortization of the discount component and debt issue fees recognized as interest expense 3,511 3,839 7,347 7,631 Total interest expense on the convertible debt $ 4,583 $ 5,277 $ 9,658 $ 10,506

Prepayments (Tables)

Prepayments (Tables)	6 Months Ended
	Jul. 04, 2021
Prepayments [Abstract]
Schedule of Prepayments and other assets	Prepayments consist of the following and are included in prepayments and other assets on the balance sheet: July 4, 2021 December 31, 2020 (in thousands) Contract manufacturer and supplier prepayments $ 320,111 $ 212,286 Prepaid maintenance and other services 16,848 13,116 Prepaid taxes 13,017 9,361 Other prepayments 9,434 15,329 Total prepayments $ 359,410 $ 250,092

Deferred Revenue and Customer_2

Deferred Revenue and Customer Advances (Tables)	6 Months Ended
	Jul. 04, 2021
Revenue Recognition and Deferred Revenue [Abstract]
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: July 4, 2021 December 31, 2020 (in thousands) Maintenance, service and training $ 83,557 $ 77,654 Extended warranty 63,525 51,929 Customer advances, undelivered elements and other 60,334 63,438 Total deferred revenue and customer advances $ 207,416 $ 193,021

Product Warranty (Tables)

Product Warranty (Tables)	6 Months Ended
	Jul. 04, 2021
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 For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Balance at beginning of period $ 23,893 $ 10,971 $ 16,633 $ 8,996 Accruals for warranties issued during the period 10,197 6,200 22,078 11,267 Accruals related to pre-existing warranties (3,450 ) 356 (3,003 ) 1,412 Settlements made during the period (4,964 ) (4,511 ) (10,032 ) (8,659 ) Balance at end of period $ 25,676 $ 13,016 $ 25,676 $ 13,016
Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances	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 For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Balance at beginning of period $ 53,908 $ 33,503 $ 51,929 $ 30,677 Deferral of new extended warranty revenue 16,290 11,450 23,805 19,050 Recognition of extended warranty deferred revenue (6,673 ) (4,775 ) (12,209 ) (9,549 ) Balance at end of period $ 63,525 $ 40,178 $ 63,525 $ 40,178

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jul. 04, 2021
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions	The fair value was estimated using the Monte Carlo simulation model with the following assumptions: For the Six Months Ended July 4, 2021 June 28, 2020 Risk-free interest rate 0.2% 1.5% Teradyne volatility-historical 43.9% 34.9% NYSE Composite Index volatility-historical 22.9% 11.4% Dividend yield 0.4% 0.6%
Fair Value of Stock Options Using Assumptions	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Six Months Ended July 4, 2021 June 28, 2020 Expected life (years) 5.0 5.0 Risk-free interest rate 0.4% 1.6% Volatility-historical 37.8% 31.6% Dividend yield 0.4% 0.6%

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jul. 04, 2021
Changes in Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive income (loss), which are presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gains (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Six Months Ended July 4, 2021 Balance at December 31, 2020, net of tax of $0, $1,910, $(1,126), respectively $ 25,389 $ 6,954 $ 1,173 $ 33,516 Other comprehensive loss before reclassifications, net of tax of $0, $(472), $0, respectively (15,974 ) (1,776 ) — (17,750 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(121), $(1), respectively — (441 ) (3 ) (444 ) Net current period other comprehensive loss, net of tax of $0, $(593), $(1), respectively (15,974 ) (2,217 ) (3 ) (18,194 ) Balance at July 4, 2021, net of tax of $0, $1,317, $(1,127), respectively $ 9,415 $ 4,737 $ 1,170 $ 15,322 Six Months Ended June 28, 2020 Balance at December 31, 2019, net of tax of $0, $946, $(1,124), respectively $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) Other comprehensive income before reclassifications, net of tax of $0, $1,271, $0, respectively 7,026 4,830 — 11,856 Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(421), $(1), respectively — (1,499 ) (3 ) (1,502 ) Net current period other comprehensive income (loss), net of tax of $0, $850, $(1), respectively 7,026 3,331 (3 ) 10,354 Balance at June 28, 2020, net of tax of $0, $1,796, $(1,125), respectively $ (16,488 ) $ 6,811 $ 1,177 $ (8,500 )
Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations	Reclassifications out of accumulated other comprehensive income (loss) to the statement of operations for the three and six months ended July 4, 2021 and June 28, 2020 were as follows: Details about Accumulated Other Comprehensive Income (Loss) Components For the Three Months Ended For the Six Months Ended Affected Line Item in the Statements of Operations July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Available-for-sale marketable securities: Unrealized (losses) gains, net of tax of $(2), $277, $121, $421, respectively $ (3 ) $ 983 $ 441 $ 1,499 Other (income) Defined benefit post-retirement plan: Amortization of prior service credit, net of tax of $0, $0, $1, $1, respectively 2 2 3 3 (a) Total reclassifications, net of tax of $(2), $277, $122, $422, respectively $ (1 ) $ 985 $ 444 $ 1,502 Net income (a) The amortization of prior service credit is included in the computation of net periodic postretirement benefit cost. See Note Q: “Retirement Plans.”

Goodwill and Acquired Intangi_2

Goodwill and Acquired Intangible Assets (Tables)	6 Months Ended
	Jul. 04, 2021
Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by reportable segments for the six months ended July 4, 2021, were as follows: Industrial Automation System Test Wireless Test Semiconductor Test Total (in thousands) Balance at December 31, 2020 Goodwill $ 433,752 $ 158,699 $ 361,819 $ 262,155 $ 1,216,425 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) 433,752 10,516 7,976 1,615 453,859 Foreign currency translation adjustment (12,191 ) — — (71 ) (12,262 ) Balance at July 4, 2021 Goodwill 421,561 158,699 361,819 262,084 1,204,163 Accumulated impairment losses — (148,183 ) (353,843 ) (260,540 ) (762,566 ) $ 421,561 $ 10,516 $ 7,976 $ 1,544 $ 441,597
Schedule of Estimated Intangible Assets Amortization Expense	Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2021(remainder) $ 10,636 2022 20,570 2023 20,084 2024 19,776 2025 11,756 Thereafter 5,299
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 Balance at July 4, 2021 (in thousands) Developed technology $ 272,547 $ (216,820 ) $ (2,779 ) $ 52,948 Customer relationships 57,739 (47,780 ) 191 10,150 Tradenames and trademarks 70,120 (45,187 ) 90 25,023 Total intangible assets $ 400,406 $ (309,787 ) $ (2,498 ) $ 88,121 Balance at December 31, 2020 Developed technology $ 272,547 $ (210,479 ) $ (1,610 ) $ 60,458 Customer relationships 66,239 (54,524 ) 305 12,020 Tradenames and trademarks 70,120 (42,344 ) 685 28,461 Total intangible assets $ 408,906 $ (307,347 ) $ (620 ) $ 100,939

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jul. 04, 2021
Computation of Basic and Diluted Net Income (Loss) Per Common Share	The following table sets forth the computation of basic and diluted net income per common share: For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 328,319 $ 188,908 $ 533,831 $ 365,098 Weighted average common shares-basic 165,995 165,789 166,243 166,189 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 9,578 7,599 9,944 7,466 Convertible note hedge warrant shares (2) 10,073 5,824 9,751 5,658 Restricted stock units 1,015 913 1,205 1,038 Stock options 78 132 93 133 Employee stock purchase plan 11 — 9 13 Dilutive potential common shares 20,755 14,468 21,002 14,308 Weighted average common shares-diluted 186,750 180,257 187,245 180,497 Net income per common share-basic $ 1.98 $ 1.14 $ 3.21 $ 2.20 Net income per common share-diluted $ 1.76 $ 1.05 $ 2.85 $ 2.02 (1) Incremental shares from assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.54, multiplied by 12.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.58, 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)	6 Months Ended
	Jul. 04, 2021
Defined Benefit Pension Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three and six months ended July 4, 2021 and June 28, 2020, Teradyne’s net periodic pension cost was comprised of the following: For the Three Months Ended July 4, 2021 June 28, 2020 United States Foreign United States Foreign (in thousands) Service cost $ 452 $ 245 $ 433 $ 208 Interest cost 1,096 88 1,523 119 Expected return on plan assets (936 ) (17 ) (1,232 ) (15 ) Net actuarial (gain) loss (400 ) — 180 — Total net periodic pension cost $ 212 $ 316 $ 904 $ 312 For the Six Months Ended July 4, 2021 June 28, 2020 UnitedStates Foreign UnitedStates Foreign (in thousands) Service cost $ 905 $ 491 $ 866 $ 417 Interest cost 2,196 175 3,045 238 Expected return on plan assets (1,872 ) (33 ) (2,464 ) (31 ) Net actuarial (gain) loss (400 ) — 180 — Total net periodic pension cost $ 829 $ 633 $ 1,627 $ 624
Postretirement Benefit Plans
Net Periodic Pension and Postretirement Benefit Costs	For the three and six months ended July 4, 2021 and June 28, 2020, Teradyne’s net periodic postretirement benefit credit was comprised of the following: For the Three Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Service cost $ 17 $ 17 $ 33 $ 28 Interest cost 41 58 85 120 Amortization of prior service credit (2 ) (2 ) (4 ) (4 ) Net actuarial gain (228 ) (279 ) (228 ) (279 ) Total net periodic postretirement benefit credit $ (172 ) $ (206 ) $ (114 ) $ (135 )

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jul. 04, 2021
Reconciliation of Effective Tax Rate	A reconciliation of the United States federal statutory corporate tax rate to Teradyne’s effective tax rate was as follows: For the Three Months Ended For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 U.S. statutory federal tax rate 21.0 % 21.0 % 21.0 % 21.0 % Foreign taxes (4.3 ) (4.6 ) (4.5 ) (5.1 ) International provisions of the U.S. Tax Cuts and Jobs Act of 2017 (1.7 ) (1.9 ) (1.6 ) (1.1 ) Tax credits (1.2 ) (1.4 ) (1.2 ) (1.6 ) Discrete benefit related to equity compensation (0.2 ) (0.1 ) (2.4 ) (2.0 ) Other, net 0.9 0.1 0.9 0.7 Effective tax rate 14.5 % 13.1 % 12.2 % 11.9 %

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jul. 04, 2021
Segment Information	Segment information for the three and six months ended July 4, 2021 and June 28, 2020 is as follows: Semiconductor Test System Test Industrial Automation Wireless Test Corporate and Other Consolidated (in thousands) Three Months Ended July 4, 2021 Revenues $ 833,976 $ 104,819 $ 92,186 $ 54,893 $ (146 ) $ 1,085,728 Income (loss) before income taxes (1)(2) 337,302 33,954 (9,837 ) 21,472 1,135 384,026 Total assets (3) 1,518,941 146,296 687,022 117,702 1,530,961 4,000,922 Three Months Ended June 28, 2020 Revenues $ 659,147 $ 71,806 $ 58,776 $ 49,185 $ (253 ) $ 838,661 Income (loss) before income taxes (1)(2) 228,787 19,193 (11,403 ) 14,482 (33,768 ) 217,291 Total assets (3) 1,192,355 126,164 662,103 108,066 1,160,501 3,249,189 Six Months Ended July 4, 2021 Revenues $ 1,362,039 $ 237,656 $ 172,137 $ 95,791 $ (289 ) $ 1,867,334 Income (loss) before income taxes (1)(2) 513,670 85,015 (22,804 ) 31,088 1,050 608,019 Total assets (3) 1,518,941 146,296 687,022 117,702 1,530,961 4,000,922 Six Months Ended June 28, 2020 Revenues $ 1,143,636 $ 187,882 $ 119,081 $ 92,670 $ (253 ) $ 1,543,016 Income (loss) before income taxes (1)(2) 382,603 67,600 (26,738 ) 24,702 (33,808 ) 414,359 Total assets (3) 1,192,355 126,164 662,103 108,066 1,160,501 3,249,189 (1) Included in Corporate and Other are: contingent consideration adjustments, loss on convertible debt conversions, interest income, interest expense, net foreign exchange gains (losses), pension, intercompany eliminations and acquisition related: (a) charges; (b) legal fees; (c) compensation. (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, loss on convertible debt conversions 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 For the Six Months Ended July 4, 2021 June 28, 2020 July 4, 2021 June 28, 2020 (in thousands) Semiconductor Test: Cost of revenues - inventory charge $ — $ 3,799 $ 1,234 $ 6,825 Restructuring and other - c — 4,000 — 4,000 Industrial Automation: Restructuring and other - acquisition related expenses and compensation $ — $ — $ 550 $ 790 Cost of revenues - inventory charge — — 1,285 — Wireless: Cost of revenues - inventory charge $ — $ 1,582 $ 672 $ 2,155 Corporate and Other: Restructuring and other - other $ 1,700 $ 750 $ 1,846 $ 750 Other (income) expense, net - l 1,175 — 5,244 — Restructuring and other - AutoGuide contingent consideration adjustment — 29,927 (7,227 ) 22,785 Restructuring and other - acquisition related expenses and compensation — 2,974 (513 ) 3,715 Restructuring and other - MiR contingent consideration adjustment — (668 ) — (3,546 )

Investment In Other Company - A

Investment In Other Company - Additional Information (Details) - MachineMetrics, Inc [Member] - USD ($) $ in Millions	3 Months Ended
	Jul. 04, 2021	Jun. 01, 2021
Schedule of Equity Method Investments [Line Items]
Long-term Investments	$ 12	$ 12
Unrealized Gain (Loss) on Investments	$ 0

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Deferred Revenue And Customer Advances	$ 22	$ 21.1	$ 49.6	$ 60.6
Deferred Revenue and Trade Accounts Receivable	7.6	$ 50	14.9	$ 96.8
Revenue, Remaining Performance Obligation, Amount	$ 1,276		$ 1,276
Short-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	94.00%		94.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			12 months
Long-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	6.00%		6.00%
Long-term Contract with Customer [Member] | Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			3 years
Long-term Contract with Customer [Member] | Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period			1 year

Disaggregated Revenue by Primar

Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 04, 2021		Jun. 28, 2020		Jul. 04, 2021		Jun. 28, 2020
Disaggregation of Revenue [Line Items]
Total	$ 1,085,728	[1]	$ 838,661	[1]	$ 1,867,334	[2]	$ 1,543,016	[2]
Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	833,976		659,147		1,362,039		1,143,636
System Test
Disaggregation of Revenue [Line Items]
Total	104,819	[1]	71,806	[1]	237,656	[2]	187,882	[2]
Industrial Automation
Disaggregation of Revenue [Line Items]
Total	92,186		58,776		172,137		119,081
Wireless Test
Disaggregation of Revenue [Line Items]
Total	54,893	[1]	49,185	[1]	95,791	[2]	92,670	[2]
Corporate and Other
Disaggregation of Revenue [Line Items]
Total	(146)	[1]	(253)	[1]	(289)	[2]	(253)	[2]
Point in Time
Disaggregation of Revenue [Line Items]
Total	989,363	[1]	760,771	[1]	1,690,447	[2]	1,387,705	[2]
Point in Time | System Test
Disaggregation of Revenue [Line Items]
Total	88,197	[1]	57,741	[1]	207,511	[2]	158,453	[2]
Point in Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	51,619	[1]	46,347	[1]	89,499	[2]	87,403	[2]
Point in Time | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	(146)	[1]	(253)	[1]	(289)	[2]	(253)	[2]
Over Time
Disaggregation of Revenue [Line Items]
Total	96,365	[1]	77,890	[1]	176,887	[2]	155,311	[2]
Over Time | System Test
Disaggregation of Revenue [Line Items]
Total	16,622	[1]	14,065	[1]	30,145	[2]	29,429	[2]
Over Time | Wireless Test
Disaggregation of Revenue [Line Items]
Total	3,274	[1]	2,838	[1]	6,292	[2]	5,267	[2]
Americas
Disaggregation of Revenue [Line Items]
Total	100,467	[1]	68,407	[1]	181,476	[2]	145,346	[2]
Americas | System Test
Disaggregation of Revenue [Line Items]
Total	36,256	[1]	28,494	[1]	63,915	[2]	56,784	[2]
Americas | Wireless Test
Disaggregation of Revenue [Line Items]
Total	7,107	[1]	5,353	[1]	12,876	[2]	10,041	[2]
Americas | Corporate and Other
Disaggregation of Revenue [Line Items]
Total	(146)	[1]	(253)	[1]	(289)	[2]	(253)	[2]
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total	59,600	[1]	43,988	[1]	114,580	[2]	102,231	[2]
Europe, Middle East and Africa | System Test
Disaggregation of Revenue [Line Items]
Total	7,333	[1]	4,656	[1]	12,991	[2]	12,424	[2]
Europe, Middle East and Africa | Wireless Test
Disaggregation of Revenue [Line Items]
Total	1,984	[1]	1,925	[1]	3,581	[2]	2,918	[2]
Asia Pacific
Disaggregation of Revenue [Line Items]
Total	925,661	[1]	726,266	[1]	1,571,278	[2]	1,295,439	[2]
Asia Pacific | System Test
Disaggregation of Revenue [Line Items]
Total	61,230	[1]	38,656	[1]	160,750	[2]	118,674	[2]
Asia Pacific | Wireless Test
Disaggregation of Revenue [Line Items]
Total	45,802	[1]	41,907	[1]	79,334	[2]	79,711	[2]
SOC | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	741,670	[1]	574,573	[1]	1,161,900	[2]	974,713	[2]
SOC | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	675,958	[1]	520,496	[1]	1,040,148	[2]	868,542	[2]
SOC | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	65,712	[1]	54,077	[1]	121,752	[2]	106,171	[2]
SOC | Americas | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	21,664	[1]	16,251	[1]	42,443	[2]	33,637	[2]
SOC | Europe, Middle East and Africa | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	9,011	[1]	10,622	[1]	21,226	[2]	30,643	[2]
SOC | Asia Pacific | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	710,995	[1]	547,700	[1]	1,098,231	[2]	910,433	[2]
Memory | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	92,306	[1]	84,574	[1]	200,139	[2]	168,923	[2]
Memory | Point in Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	84,232	[1]	80,032	[1]	186,124	[2]	159,429	[2]
Memory | Over Time | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	8,074	[1]	4,542	[1]	14,015	[2]	9,494	[2]
Memory | Americas | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	3,672	[1]	855	[1]	7,092	[2]	7,751	[2]
Memory | Europe, Middle East and Africa | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	1,483	[1]	1,227	[1]	1,847	[2]	2,571	[2]
Memory | Asia Pacific | Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	87,151	[1]	82,492	[1]	191,200	[2]	158,601	[2]
Universal Robots (UR) | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	76,077	[1]	43,551	[1]	141,678	[2]	93,248	[2]
Universal Robots (UR) | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	74,412	[1]	41,804	[1]	138,419	[2]	89,306	[2]
Universal Robots (UR) | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	1,665	[1]	1,747	[1]	3,259	[2]	3,942	[2]
Universal Robots (UR) | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	24,808	[1]	11,364	[1]	42,961	[2]	26,108	[2]
Universal Robots (UR) | Europe, Middle East and Africa | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	33,225	[1]	17,908	[1]	62,840	[2]	41,945	[2]
Universal Robots (UR) | Asia Pacific | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	18,044	[1]	14,279	[1]	35,877	[2]	25,195	[2]
MiR | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	15,900	[1]	11,272	[1]	30,031	[2]	20,410	[2]
MiR | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	15,091	[1]	11,196	[1]	29,155	[2]	20,293	[2]
MiR | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	809	[1]	76	[1]	876	[2]	117	[2]
MiR | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	6,897	[1]	2,390	[1]	12,050	[2]	5,855	[2]
MiR | Europe, Middle East and Africa | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	6,564	[1]	7,650	[1]	12,095	[2]	11,730	[2]
MiR | Asia Pacific | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	2,439	[1]	1,232	[1]	5,886	[2]	2,825	[2]
Autoguide LLC [Member] | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	209	[1]	3,953	[1]	428	[2]	5,423	[2]
Autoguide LLC [Member] | Point in Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	0	[1]	3,408	[1]	(120)	[2]	4,532	[2]
Autoguide LLC [Member] | Over Time | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	209	[1]	545	[1]	548	[2]	891	[2]
Autoguide LLC [Member] | Americas | Industrial Automation
Disaggregation of Revenue [Line Items]
Total	$ 209	[1]	$ 3,953	[1]	$ 428	[2]	$ 5,423	[2]
[1]	Includes $4.2 million and $2.5 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.”
[2]	Includes $7.3 million and $4.3 million in 2021 and 2020, respectively, 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		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Accounting Policies [Abstract]
Revenue on leases	$ 4.2	$ 2.5	$ 7.3	$ 4.3

Composition of Inventories, Net

Composition of Inventories, Net (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw material	$ 117,339	$ 114,133
Work-in-process	37,884	25,408
Finished goods	70,915	82,648
Inventories, net	$ 226,138	$ 222,189

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	Jul. 04, 2021	Dec. 31, 2020
Inventory [Line Items]
Inventory reserves	$ 106.9	$ 110.6

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020	Dec. 31, 2020
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized gain	$ 0.9	$ 1.6	$ 2	$ 3
Available-for-sale securities, realized loss		0.1		0.2
Fair market value of investments with unrealized losses less than one year	130.7		130.7		$ 70.4
Unrealized Gain (loss) on contracts	0.1	$ 0.4	0.3	1.6
Equity securities unrealized gain	2		3.3	3.7
Equity securities unrealized loss			0.7	$ 6
Debt Mutual Funds
Financial Instruments and Fair Value [Line Items]
Available for sale securities with out contractual maturity date	$ 8		8
Foreign Exchange Contracts
Financial Instruments and Fair Value [Line Items]
Unrealized Gain (loss) on contracts			$ 206.9		$ 152.9

Schedule of Fair Value of Finan

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 427,523	$ 610,840
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	102,316	258,304
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	225,415	254,413
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	85,294	83,615
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	1,344	979
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,508	4,339
Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	8,030	8,565
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	616	625
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	1,418,122	1,554,381
Derivative assets	25	95
Total	1,418,147	1,554,476
Contingent consideration		7,227
Derivative liabilities	365	504
Total	365	7,731
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	568,630	443,166
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	385,811	470,955
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	102,316	258,304
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	225,415	254,413
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	85,294	83,615
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	1,344	979
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,508	4,339
Fair Value, Measurements, Recurring | Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	8,030	8,565
Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	616	625
Fair Value, Measurements, Recurring | Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	36,158	29,420
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	985,931	828,919
Total	985,931	828,919
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	568,630	443,166
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	373,113	347,768
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	8,030	8,565
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	36,158	29,420
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	432,191	725,462
Derivative assets	25	95
Total	432,216	725,557
Derivative liabilities	365	504
Total	365	504
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	12,698	123,187
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	102,316	258,304
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	225,415	254,413
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	85,294	83,615
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	1,344	979
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	4,508	4,339
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	$ 616	625
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		7,227
Total		$ 7,227

Schedule of Reported Financial

Schedule of Reported Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 1,418,147	$ 1,554,476
Liabilities	365	7,731
Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	365	504
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	954,441	914,121
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	282,121	522,280
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	181,560	117,980
Prepayments and other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	25	95
Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities		7,227
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	985,931	828,919
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	941,743	790,934
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	44,188	37,985
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	432,216	725,557
Liabilities	365	504
Significant Other Observable Inputs (Level 2) | Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	365	504
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	12,698	123,187
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	282,121	522,280
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	137,372	79,995
Significant Other Observable Inputs (Level 2) | Prepayments and other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 25	95
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities		7,227
Significant Unobservable Inputs (Level 3) | Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities		$ 7,227

Schedule of Changes in Fair Val

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period		$ 0	$ 20,472	$ 7,227	$ 39,705
Fair value adjustment	[1],[2]	0	29,259	(7,227)	19,239
Foreign currency impact		0	6	0	(355)
Payments	[3]	0	0	0	(8,852)
Balance at end of period		$ 0	$ 49,737	$ 0	$ 49,737
[1]	In the six months ended July 4, 2021, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide was reduced to zero, which resulted in a benefit of $7.2 million, primarily due to a decrease in forecasted revenues and earnings before interest and taxes. As of July 4, 2021, the maximum amount of contingent consideration that could be paid in connection with the acquisition of AutoGuide is $100.2 million. The remaining earn-out periods end on December 31, 2021 and December 31, 2022. The sellers of AutoGuide have filed an arbitration claim against Teradyne related to allegations of non-compliance with its earn-out obligations. The ultimate amount of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide may be affected by the outcome of the arbitration (see Note:R).
[2]	In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of Mobile Industrial Robots (“MiR”) decreased by $0.6 million and $3.6 million, respectively, due to lower forecasted results. In the three and six months ended June 28, 2020, the fair value of contingent consideration for the earn-outs in connection with the acquisition of AutoGuide increased by $29.9 million and $22.8 million, respectively, due to higher forecasted results.
[3]	In the six months ended June 28, 2020, Teradyne paid $8.9 million of contingent consideration for the earn-out in connection with the acquisition of MiR.

Schedule of Changes in Fair V_2

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			$ 8,852
Increase (decrease) in contingent consideration		$ (7,227)	19,239
Maximum amount of contingent consideration paid for acquisition			8,852
Investments with unrealized losses		1,300
Avionics Interface Technologies, LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			8,900
Maximum amount of contingent consideration paid for acquisition			8,900
MiR
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	$ 600		3,600
Maximum amount of contingent consideration paid for acquisition	600		3,600
Autoguide LLC [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration	29,900	100,200	22,800
Maximum amount of contingent consideration paid for acquisition	$ 29,900	100,200	$ 22,800
Autoguide LLC [Member] | Dispute In Respect Of Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Increase (decrease) in contingent consideration		$ 7,200

Schedule of Carrying Amounts an

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Jul. 04, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Marketable securities		$ 427,523	$ 610,840
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		954,441	914,121
Marketable securities		463,681	640,260
Derivative assets		25	95
Contingent consideration			7,227
Derivative liabilities		365	504
Convertible debt	[1]	357,379	410,111
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		954,441	914,121
Marketable securities		463,681	640,260
Derivative assets		25	95
Contingent consideration			7,227
Derivative liabilities		365	504
Convertible debt	[1]	$ 1,595,912	$ 1,739,553
[1]	The carrying value represents the bifurcated debt component only, while the level 2 fair value is based on quoted market prices for the convertible note, which includes the equity conversion features.

Schedule of Available for Sale

Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 421,469	$ 601,976
Available-for-sale marketable securities, Unrealized Gain	6,684	9,077
Available-for-sale marketable securities, Unrealized (Loss)	(630)	(213)
Available-for-sale marketable securities, Fair Market Value	427,523	610,840
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	131,946	70,418
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	102,068	257,132
Available-for-sale marketable securities, Unrealized Gain	767	1,330
Available-for-sale marketable securities, Unrealized (Loss)	(519)	(158)
Available-for-sale marketable securities, Fair Market Value	102,316	258,304
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	72,750	17,243
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	225,409	254,404
Available-for-sale marketable securities, Unrealized Gain	7	10
Available-for-sale marketable securities, Unrealized (Loss)	(1)	(1)
Available-for-sale marketable securities, Fair Market Value	225,415	254,413
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	19,194	12,173
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	79,586	76,129
Available-for-sale marketable securities, Unrealized Gain	5,814	7,539
Available-for-sale marketable securities, Unrealized (Loss)	(106)	(53)
Available-for-sale marketable securities, Fair Market Value	85,294	83,615
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	38,694	39,896
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	1,344	979
Available-for-sale marketable securities, Unrealized Gain	0
Available-for-sale marketable securities, Fair Market Value	1,344	979
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	4,490	4,294
Available-for-sale marketable securities, Unrealized Gain	22	46
Available-for-sale marketable securities, Unrealized (Loss)	(4)	(1)
Available-for-sale marketable securities, Fair Market Value	4,508	4,339
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	1,308	1,106
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	7,956	8,413
Available-for-sale marketable securities, Unrealized Gain	74	152
Available-for-sale marketable securities, Fair Market Value	8,030	8,565
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	616	625
Available-for-sale marketable securities, Fair Market Value	$ 616	$ 625

Schedule of Reported Available

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 421,469	$ 601,976
Available-for-sale marketable securities, Unrealized Gain	6,684	9,077
Available-for-sale marketable securities, Unrealized (Loss)	(630)	(213)
Available-for-sale marketable securities, Fair Market Value	427,523	610,840
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	131,946	70,418
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	282,061	522,228
Available-for-sale marketable securities, Unrealized Gain	93	92
Available-for-sale marketable securities, Unrealized (Loss)	(33)	(40)
Available-for-sale marketable securities, Fair Market Value	282,121	522,280
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	59,990	61,806
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	139,408	79,748
Available-for-sale marketable securities, Unrealized Gain	6,591	8,985
Available-for-sale marketable securities, Unrealized (Loss)	(597)	(173)
Available-for-sale marketable securities, Fair Market Value	145,402	88,560
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 71,956	$ 8,612

Contractual Maturities of Inves

Contractual Maturities of Investments in Debt Securities Held (Detail) $ in Thousands	Jul. 04, 2021USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 282,061
Due after 1 year through 5 years, cost	90,625
Due after 5 years through 10 years, cost	6,089
Due after 10 years, cost	34,738
Total, cost	413,513
Due within one year, fair market value	282,121
Due after 1 year through 5 years, fair market value	90,940
Due after 5 years through 10 years, fair market value	6,585
Due after 10 years, fair maket value	39,847
Total, fair market value	$ 419,493

Schedule of Derivative Instrume

Schedule of Derivative Instruments in Statement of Financial Position at Fair Value (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative assets (liabilities), net	$ (340)	$ (409)
Not Designated as Hedging Instrument | Foreign currency forward contracts | Prepayments
Derivatives, Fair Value [Line Items]
Derivative assets	25	95
Not Designated as Hedging Instrument | Foreign currency forward contracts | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (365)	$ (504)

Schedule of Effect of Derivativ

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Losses (Gains) on derivatives recognized in statements of operations	$ 1,531	$ 470	$ 3,650	$ 4,481

Schedule of Effect of Derivat_2

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on foreign currency transactions	$ 0.1	$ 0.4	$ 0.3	$ 1.6

Debt - Additional Information (

Debt - Additional Information (Detail)	Aug. 05, 2021USD ($)	May 01, 2020USD ($)	Dec. 12, 2016USD ($)Customer$ / sharesshares	Sep. 30, 2021USD ($)	Jul. 04, 2021USD ($)$ / sharesshares	Jun. 28, 2020USD ($)shares	Dec. 31, 2020USD ($)
Debt Instrument
Repurchase of common stock					$ 196,584,000	$ 88,465,000
Repurchase of stock, shares | shares					1,600,000	1,500,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 400,000,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases		$ 150,000,000
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.
Term of revolving credit facility		3 years
Convertible common shares					$ 21,386,000		$ 3,787,000
Convertible Common Shares [Member]
Debt Instrument
Convertible common shares					66,800,000
Shares Issued, Stock Options Exercised					1,600,000
Subsequent Event [Member] | Convertible Common Shares [Member]
Debt Instrument
Increase in debt principal, Additional conversion				$ 235,200,000
Collateral Pledged [Member]
Debt Instrument
Line of Credit Facility, Interest Rate Description		65
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Aggregate principal amount			$ 460,000,000		393,142,000		$ 459,971,000
Debt instrument, interest rate, stated percentage			1.25%
Debt instrument, net proceeds after issuance costs			$ 450,800,000
Payment for net cost of convertible note hedges net of warrant proceeds			33,000,000		$ 33,000,000
Repurchase of common stock			$ 50,100,000
Repurchase of stock, shares | shares			2,000,000
Senior notes maturity date			Dec. 15, 2023
Debt instrument, frequency of periodic payment			payable semiannually in arrears on June 15 and December 15 of each year.
Debt instrument, date of first required payment			Jun. 15, 2017
Debt instrument, conversion option expiration date			Sep. 15, 2023
Debt instrument conversion price | $ / shares			$ 31.54		$ 31.54
Shares that would be issued upon conversion | shares			14.6		12,500,000
Strike price per share of warrant | $ / shares					$ 39.58
Debt instrument, convertible, carrying amount of equity component					$ 100,800,000	$ 100,800,000
Debt instrument, effective annual interest rate					5.00%
Financing cost					$ 2,400,000	$ 7,200,000
Debt issuance costs, amortization period						7 years
Unamortized discount					35,800,000
Debt Instrument, convertible, remaining discount amortization period							2 years 6 months
Value of notes converted					1,602,200,000
1.25% Convertible Senior Unsecured Notes Due December 15, 2023 | Subsequent Event [Member]
Debt Instrument
Debt instrument conversion converted instrument amount	$ 302,000,000
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%
Revolving Credit Facility
Debt Instrument
Revolving credit facility costs incurred					$ 3,500,000

Components of Convertible Senio

Components of Convertible Senior Notes (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Dec. 12, 2016
Debt Instrument
Current debt	$ 213,761	$ 33,343
Long-term debt	143,618	376,768
Net carrying amount of convertible debt	357,379	410,111
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Debt principal	393,142	459,971	$ 460,000
Unamortized discount	35,763	49,860
Net carrying amount of convertible debt	$ 357,379	$ 410,111

Interest Expense on Convertible

Interest Expense on Convertible Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Debt Instrument
Contractual interest expense on the coupon	$ 1,072	$ 1,438	$ 2,311	$ 2,875
Amortization of the discount component and debt issue fees recognized as interest expense	3,511	3,839	7,347	7,631
Total interest expense on the convertible debt	$ 4,583	$ 5,277	$ 9,658	$ 10,506

Prepayments (Detail)

Prepayments (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020
Prepaid And Other Current Assets [Line Items]
Contract manufacturer and supplier prepayments	$ 320,111	$ 212,286
Prepaid maintenance and other services	16,848	13,116
Prepaid taxes	13,017	9,361
Other prepayments	9,434	15,329
Total prepayments	$ 359,410	$ 250,092

Deferred Revenue and Customer_3

Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Jul. 04, 2021	Apr. 04, 2021	Dec. 31, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 31, 2019
Deferred Revenue Arrangement
Maintenance, service and training	$ 83,557		$ 77,654
Extended warranty	63,525	$ 53,908	51,929	$ 40,178	$ 33,503	$ 30,677
Customer advances, undelivered elements and other	60,334		63,438
Total deferred revenue and customer advances	$ 207,416		$ 193,021

Product Warranty (Detail)

Product Warranty (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 23,893	$ 10,971	$ 16,633	$ 8,996
Accruals for warranties issued during the period	10,197	6,200	22,078	11,267
Accruals related to pre-existing warranties	(3,450)	356	(3,003)	1,412
Settlements made during the period	(4,964)	(4,511)	(10,032)	(8,659)
Balance at end of period	$ 25,676	$ 13,016	$ 25,676	$ 13,016

Extended Product Warranty of Sh

Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 53,908	$ 33,503	$ 51,929	$ 30,677
Deferral of new extended warranty revenue	16,290	11,450	23,805	19,050
Recognition of extended warranty deferred revenue	(6,673)	(4,775)	(12,209)	(9,549)
Balance at end of period	$ 63,525	$ 40,178	$ 63,525	$ 40,178

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - $ / shares shares in Millions	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Sep. 27, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Stock price		$ 72.10	$ 113.48
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	$ 0.40
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
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	$ 125.02	$ 89.93
Stock price	0.40	72.10
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	113.48
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%
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%
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	$ 113.65	$ 70.94
Service-Based Restricted Stock Units | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted	0.3	0.4
Weighted average grant date fair value of restricted stock units granted	$ 113.23	$ 70.52
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	$ 36.60	20.67
Service-Based Restricted Stock Units | Non Employee Directors
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	$ 127.77	$ 64.99

Schedule of Estimated Fair Valu

Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions (Detail)	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Expected historical volatility	37.80%	31.60%
New York Stock Exchange Composite Index
Share-based Compensation Arrangement by Share-based Payment Award
Expected historical volatility	22.90%	11.40%
TSR Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	0.20%	1.50%
Expected historical volatility	43.90%	34.90%
Dividend yield	0.40%	0.60%

Schedule of Estimated Fair Va_2

Schedule of Estimated Fair Value of Stock Options Grant Using Black Scholes Option Pricing Model (Detail)	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Volatility-historical	37.80%	31.60%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Expected life (years)	5 years	5 years
Risk-free interest rate	0.40%	1.60%
Dividend yield	0.40%	0.60%

Changes in Accumulated Other Co

Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020		Jul. 04, 2021		Jun. 28, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		$ 2,324,553	$ 1,550,673		$ 2,207,018		$ 1,480,158
Other comprehensive income (loss)		6,645	18,613		(18,194)		10,354
Balance		2,493,256	1,744,551		2,493,256		1,744,551
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance					25,389		(23,514)
Other comprehensive (loss) income before reclassifications, net of tax					(15,974)		7,026
Amounts reclassified from accumulated other comprehensive income (loss), net of tax					0		0
Other comprehensive income (loss)					(15,974)		7,026
Balance		9,415	(16,488)		9,415		(16,488)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance					6,954		3,480
Other comprehensive (loss) income before reclassifications, net of tax					(1,776)		4,830
Amounts reclassified from accumulated other comprehensive income (loss), net of tax					(441)		(1,499)
Other comprehensive income (loss)					(2,217)		3,331
Balance		4,737	6,811		4,737		6,811
Retirement Plans Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance					1,173		1,180
Other comprehensive (loss) income before reclassifications, net of tax					0		0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	[1]	(2)	(2)		(3)		(3)
Other comprehensive income (loss)					(3)		(3)
Balance		1,170	1,177		1,170		1,177
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		8,677	(27,113)		33,516		(18,854)
Other comprehensive (loss) income before reclassifications, net of tax					(17,750)		11,856
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		1	(985)	[1]	(444)	[1]	(1,502)	[1]
Other comprehensive income (loss)		6,645	18,613		(18,194)		10,354
Balance		$ 15,322	$ (8,500)		$ 15,322		$ (8,500)
[1]	The amortization of prior service credit is included in the computation of net periodic postretirement benefit cost. See Note Q: “Retirement Plans.”

Changes in Accumulated Other _2

Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss), tax	$ 2	$ (277)	$ (122)	$ (422)
Foreign currency translation adjustments, tax	0	0	0	0	$ 0	$ 0
Unrealized (losses) gains on marketable securities, tax	1,317	1,796	1,317	1,796	1,910	946
Retirement plans prior service benefit, tax	(1,127)	(1,125)	(1,127)	(1,125)	$ (1,126)	$ (1,124)
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			(472)	1,271
Amounts reclassified from accumulated other comprehensive income (loss), tax	2	(277)	(121)	(421)
Other comprehensive income (loss), tax			(593)	850
Retirement Plans 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	$ 0	(1)	(1)
Other comprehensive income (loss), tax			$ (1)	$ (1)

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income (Loss) to Statements of Operations (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020		Jul. 04, 2021		Jun. 28, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)		$ (3)	$ 983		$ 441		$ 1,499
Retirement Plans Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	[1]	2	2		3		3
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax		$ (1)	$ 985	[1]	$ 444	[1]	$ 1,502	[1]
[1]	The amortization of prior service credit is included in the computation of net periodic postretirement benefit cost. See Note Q: “Retirement Plans.”

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income (Loss) to Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ (2)	$ 277	$ 122	$ 422
Unrealized (Losses) Gains on Marketable Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	(2)	277	121	421
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 0	$ 0	$ 1	$ 1

Goodwill and Acquired Intangi_3

Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Goodwill and Intangible Assets Disclosure [Line Items]
Acquired intangible assets amortization	$ 5,402	$ 8,941	$ 10,938	$ 18,832

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 04, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 1,204,163	$ 1,216,425
Accumulated impairment losses	(762,566)	(762,566)
Foreign currency translation adjustment	(12,262)
Goodwill	441,597	453,859
Industrial Automation
Goodwill [Line Items]
Goodwill	421,561	433,752
Accumulated impairment losses	0	0
Foreign currency translation adjustment	(12,191)
Goodwill	421,561	433,752
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)
Foreign currency translation adjustment	0
Goodwill	7,976	7,976
Semiconductor Test
Goodwill [Line Items]
Goodwill	262,084	262,155
Accumulated impairment losses	(260,540)	(260,540)
Foreign currency translation adjustment	(71)
Goodwill	1,544	1,615
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)
Foreign currency translation adjustment	0
Goodwill	$ 10,516	$ 10,516

Schedule of Amortizable Intangi

Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 04, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 400,406	$ 408,906
Accumulated Amortization	(309,787)	(307,347)
Foreign Currency Translation Adjustment	(2,498)	(620)
Net Carrying Amount	88,121	100,939
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	272,547	272,547
Accumulated Amortization	(216,820)	(210,479)
Foreign Currency Translation Adjustment	(2,779)	(1,610)
Net Carrying Amount	52,948	60,458
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	57,739	66,239
Accumulated Amortization	(47,780)	(54,524)
Foreign Currency Translation Adjustment	191	305
Net Carrying Amount	10,150	12,020
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount	70,120	70,120
Accumulated Amortization	(45,187)	(42,344)
Foreign Currency Translation Adjustment	90	685
Net Carrying Amount	$ 25,023	$ 28,461

Schedule of Estimated Intangibl

Schedule of Estimated Intangible Asset Amortization Expense (Detail) $ in Thousands	Jul. 04, 2021USD ($)
Finite-Lived Intangible Assets
2021 (remainder)	$ 10,636
2022	20,570
2023	20,084
2024	19,776
2025	11,756
Thereafter	$ 5,299

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		6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Net Income Loss Per Common Share
Net income for basic and diluted net income per share		$ 328,319	$ 188,908	$ 533,831	$ 365,098
Weighted average common shares-basic		165,995	165,789	166,243	166,189
Incremental shares from assumed conversion of convertible notes	[1]	9,578	7,599	9,944	7,466
Convertible note hedge warrant shares	[2]	10,073	5,824	9,751	5,658
Employee stock purchase plan		11	0	9	13
Dilutive potential common shares		20,755	14,468	21,002	14,308
Weighted average common shares-diluted		186,750	180,257	187,245	180,497
Net income per common share-basic		$ 1.98	$ 1.14	$ 3.21	$ 2.20
Net income per common share-diluted		$ 1.76	$ 1.05	$ 2.85	$ 2.02
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		1,015	913	1,205	1,038
Stock Options
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		78	132	93	133
[1]	Incremental shares from assumed conversion of the convertible notes were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.54, multiplied by 12.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
[2]	Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.58, 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	6 Months Ended
	Jul. 04, 2021$ / sharesshares
Convertible Notes
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 31.54
Shares that would be issued upon conversion | shares	12.7
Convertible Notes Hedge Warrant
Net Income Loss Per Common Share
Initial debt conversion price | $ / shares	$ 39.58
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	6 Months Ended
	Jun. 28, 2020	Jun. 28, 2020
Net Income Loss Per Common Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0.2

Restructuring and Other - Addit

Restructuring and Other - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Restructuring Cost and Reserve
Contingent consideration adjustment			$ (7,227)	$ 19,239
Severance benefit and charges	$ 400		600
Restructuring and other	400		300
Increase Decrease in environmental and legal liabilities	$ 1,700		1,700
MiR Contingent Consideration Liability [Member]
Restructuring Cost and Reserve
Contingent consideration adjustment		$ 600		3,600
Semiconductor Test
Restructuring Cost and Reserve
Severance benefit and charges				800
Acquisition related costs		3,100		4,500
Loss on Contract Termination		4,000		4,000
Semiconductor Test, Industrial Automation and Corporate
Restructuring Cost and Reserve
Restructuring and other		800		1,100
Semiconductor Test, Industrial Automation and Corporate | Mobile Industrial Robots (MiR)
Restructuring Cost and Reserve
Contingent consideration adjustment		$ 29,900	$ 7,200	$ 22,800

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - United States Plans - Annuity Plan For Participants In The US Qualified Pension Plan [Member] - USD ($) $ in Millions	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020
Defined Benefit Plan Disclosure
Pension benefit obligation acturial gain loss	$ 1.7	$ 1.4
Defined benefit obligation increase decrease for remeasurement due to settlement	$ 0.5	$ 0.4

Schedule of Net Periodic Pensio

Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Defined Benefit Plan Disclosure
Net actuarial loss (gain)			$ (627)	$ (99)
UNITED STATES
Defined Benefit Plan Disclosure
Service cost	$ 452	$ 433	905	866
Interest cost	1,096	1,523	2,196	3,045
Expected return on plan assets	(936)	(1,232)	(1,872)	(2,464)
Net actuarial loss (gain)	(400)	180	(400)	180
Total net periodic pension cost	212	904	829	1,627
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	245	208	491	417
Interest cost	88	119	175	238
Expected return on plan assets	(17)	(15)	(33)	(31)
Total net periodic pension cost	316	312	633	624
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	17	17	33	28
Interest cost	41	58	85	120
Amortization of prior service cost	(2)	(2)	(4)	(4)
Net actuarial loss (gain)	(228)	(279)	(228)	(279)
Total net periodic pension cost	$ (172)	$ (206)	$ (114)	$ (135)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Oct. 18, 2019	Jul. 04, 2021
Purchase Commitment, Excluding Long-term Commitment
Aggregate purchase commitments		$ 770
Purchase commitments less than one year		$ 754.3
Legal claims, damage sought by party	$ 106.9

Schedule of Reconciliation of E

Schedule of Reconciliation of Effective Tax Rate (Detail)	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Income Tax Disclosure [Line Items]
US statutory federal tax rate	21.00%	21.00%	21.00%	21.00%
Foreign taxes	(4.30%)	(4.60%)	(4.50%)	(5.10%)
International provisions of the U.S. Tax Cuts and Jobs Act of 2017	(1.70%)	(1.90%)	(1.60%)	(1.10%)
Tax credits	(1.20%)	(1.40%)	(1.20%)	(1.60%)
Discrete benefit related to equity compensation	(0.20%)	(0.10%)	(2.40%)	(2.00%)
Other, net	0.90%	0.10%	0.90%	0.70%
Effective tax rate	14.50%	13.10%	12.20%	11.90%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Dec. 31, 2020
Income Taxes [Line Items]
Tax savings due to the tax holiday	$ 15.9	$ 13.6
Tax savings due to the tax holiday, per share	$ 0.08	$ 0.08
Accrued interest and penalties	$ 1.4		$ 1.2
Interest and penalties related to income tax, expense (benefit)	0.2	$ 0.3
Uncertain tax positions	16.6		$ 17.9
Net decrease in reserves for uncertain tax positions	(1.3)
Possible Lapse Of Statutes Of Limitations [Member]
Income Taxes [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 1.6

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jul. 04, 2021Segment
Segment Reporting Information [Line Items]
Number of Operating Segments	4

Schedule of Segment Information

Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jul. 04, 2021		Jun. 28, 2020		Jul. 04, 2021		Jun. 28, 2020		Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues		$ 1,085,728	[1]	$ 838,661	[1]	$ 1,867,334	[2]	$ 1,543,016	[2]
Income (loss) before income taxes	[3],[4]	384,026		217,291		608,019		414,359
Total assets		4,000,922	[5]	3,249,189	[5]	4,000,922	[5]	3,249,189	[5]	$ 3,652,346
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		833,976		659,147		1,362,039		1,143,636
Income (loss) before income taxes	[3],[4]	337,302		228,787		513,670		382,603
Total assets	[5]	1,518,941		1,192,355		1,518,941		1,192,355
System Test
Segment Reporting Information [Line Items]
Revenues		104,819	[1]	71,806	[1]	237,656	[2]	187,882	[2]
Income (loss) before income taxes	[3],[4]	33,954		19,193		85,015		67,600
Total assets	[5]	146,296		126,164		146,296		126,164
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		92,186		58,776		172,137		119,081
Income (loss) before income taxes	[3],[4]	(9,837)		(11,403)		(22,804)		(26,738)
Total assets	[5]	687,022		662,103		687,022		662,103
Wireless Test
Segment Reporting Information [Line Items]
Revenues		54,893	[1]	49,185	[1]	95,791	[2]	92,670	[2]
Income (loss) before income taxes	[3],[4]	21,472		14,482		31,088		24,702
Total assets	[5]	117,702		108,066		117,702		108,066
Corporate And Others [Member]
Segment Reporting Information [Line Items]
Revenues		(146)		(253)		(289)		(253)
Income (loss) before income taxes	[3],[4]	1,135		(33,768)		1,050		(33,808)
Total assets	[5]	$ 1,530,961		$ 1,160,501		$ 1,530,961		$ 1,160,501
[1]	Includes $4.2 million and $2.5 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.”
[2]	Includes $7.3 million and $4.3 million in 2021 and 2020, respectively, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.”
[3]	Included in Corporate and Other are: contingent consideration adjustments, loss on convertible debt conversions, interest income, interest expense, net foreign exchange gains (losses), pension, intercompany eliminations and acquisition related: (a) charges; (b) legal fees; (c) compensation.
[4]	Included in income (loss) before taxes are charges and credits related to restructuring and other, loss on convertible debt conversions and inventory charges.
[5]	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 I

Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Segment Reporting Information [Line Items]
Restructuring and other	$ 400		$ 300
Contingent consideration adjustment			(7,227)	$ 19,239
Other (income) expense, net - loss on convertible debt conversion	87	$ 4,017	(3,738)	(2,833)
Semiconductor Test
Segment Reporting Information [Line Items]
Contract termination settlement charge		4,000		4,000
Cost of revenues - inventory charge		3,799	1,234	6,825
Acquisition related costs		3,100		4,500
Industrial Automation
Segment Reporting Information [Line Items]
Cost of revenues - inventory charge			1,285
Acquisition related costs			550	790
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues - inventory charge		1,582	672	2,155
Corporate And Eliminations
Segment Reporting Information [Line Items]
Restructuring and other	1,700	750	1,846	750
Corporate And Eliminations | Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs		2,974	(513)	3,715
Other (income) expense, net - loss on convertible debt conversion	$ 1,175		5,244
Corporate And Eliminations | Universal Robots (UR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment		29,927	$ (7,227)	22,785
Corporate And Eliminations | Mobile Industrial Robots (MiR) | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment		$ (668)		$ (3,546)

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended	6 Months Ended
	Jul. 04, 2021	Jul. 04, 2021	Jun. 28, 2020	Jan. 31, 2021	Jan. 01, 2021
Cumulative repurchases, shares		1.6	1.5
Common stock average price		$ 125.69	$ 58.33
Dividends Payable, Amount Per Share				$ 0.10
Dividend payment	$ 16,600	$ 33,271	$ 33,266
Treasury Stock, Value					$ 600,000
Treasury Stock, Shares					2,000
Share Repurchase Program [Member]
Cumulative repurchases, value		$ 196,600	$ 88,500