Teradyne (TER) 10-Q 7 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 30, 2014	2-May-14
Document Information	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'TER	'
Entity Registrant Name	'TERADYNE, INC	'
Entity Central Index Key	'0000097210	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	194,252,893

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$232,626	$341,638
Marketable securities	462,150	586,882
Accounts receivable, less allowance for doubtful accounts of $2,454 and $2,912 at March 30, 2014 and December 31, 2013, respectively	216,524	157,642
Inventories:	'	'
Parts	77,072	84,232
Assemblies in process	15,131	15,539
Finished goods	45,231	38,168
Inventory, Net, Total	137,434	137,939
Deferred tax assets	68,780	72,478
Prepayments	131,484	136,374
Other current assets	12,249	7,324
Total current assets	1,261,247	1,440,277
Net property, plant and equipment	278,727	275,236
Marketable securities	272,068	271,078
Deferred tax assets	5,551	5,217
Other assets	10,574	14,591
Retirement plans assets	9,443	9,342
Intangible assets, net	234,020	252,291
Goodwill	361,819	361,792
Total assets	2,433,449	2,629,824
Current liabilities:	'	'
Accounts payable	70,597	62,874
Accrued employees' compensation and withholdings	58,687	95,619
Deferred revenue and customer advances	64,811	55,404
Other accrued liabilities	65,561	63,712
Dividend payable	11,648	'
Accrued income taxes	1,749	11,360
Current debt	'	186,663
Total current liabilities	273,053	475,632
Long-term deferred revenue and customer advances	13,981	13,756
Retirement plans liabilities	92,530	91,517
Deferred tax liabilities	50,532	40,686
Long-term other accrued liabilities	13,523	23,139
Total liabilities	443,619	644,730
Commitments and contingencies (Note O)	'	'
SHAREHOLDERS' EQUITY	'	'
Common stock, $0.125 par value, 1,000,000 shares authorized, 194,019 shares and 191,731 shares issued and outstanding at March 30, 2014 and December 31, 2013, respectively	24,253	23,966
Additional paid-in capital	1,405,175	1,390,896
Accumulated other comprehensive income	4,890	4,000
Retained earnings	555,512	566,232
Total shareholders' equity	1,989,830	1,985,094
Total liabilities and shareholders' equity	$2,433,449	$2,629,824

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Accounts receivable, less allowance for doubtful accounts	$2,454	$2,912
Common stock, par value	$0.13	$0.13
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	194,019	191,731
Common stock, shares outstanding	194,019	191,731

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 30, 2014		Mar. 31, 2013
Net revenues:	'		'
Products	$255,386		$214,300
Services	65,624		66,067
Total net revenues	321,010		280,367
Cost of revenues:	'		'
Cost of products	124,448		96,793
Cost of services	29,515		30,157
Total cost of revenues	153,963		126,950
Gross profit	167,047		153,417
Operating expenses:	'		'
Engineering and development	67,085		62,751
Selling and administrative	78,003		67,890
Acquired intangible assets amortization	18,271		18,036
Restructuring and other	'		332
Total operating expenses	163,359		149,009
Income from operations	3,688		4,408
Interest income	1,036		1,072
Interest expense and other	6,597		6,906
Loss before income taxes	-1,873	[1],[2]	-1,426	[1],[2]
Income tax benefit	-2,802		-8,015
Net income	$929		$6,589
Net income per common share:	'		'
Basic	$0		$0.03
Diluted	$0		$0.03
Weighted average common shares-basic	193,311		189,686
Weighted average common shares-diluted	236,484		234,757
Cash dividend declared per common share	$0.06		'
[1]	Interest income and interest expense and other are included in Corporate and Eliminations.
[2]	Included in the income (loss) before income taxes for each of the segments are charges and credits for the three months ended March 30, 2014 and March 31, 2013 that include restructuring and other, and provision for excess and obsolete inventory, as follows:

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014		Mar. 31, 2013
Net income	$929		$6,589
Other comprehensive income (loss):	'		'
Net unrealized gains on marketable securities arising during period, net of tax of $654, $115	1,139		200
Less: Reclassification adjustment for net gains included in net income, net of tax of $(102), $(83)	-176		-144
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	963		56
Defined benefit pension and post-retirement plans:	'		'
Amortization of prior service benefit included in net periodic pension and post-retirement expense/income, net of tax of $(42), $(40)	-73	[1]	-69	[1]
Other comprehensive income (loss)	890		-13
Comprehensive income	$1,819		$6,576
[1]	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note N: "Retirement Plans."

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Net unrealized gains on marketable securities arising during period, tax	$654	$115
Reclassification adjustment for net gains included in net income, tax	-102	-83
Amortization of prior service benefit, tax	($42)	($40)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net income	$929	$6,589
Adjustments to reconcile net income to net cash used for operating activities:	'	'
Depreciation	15,259	14,115
Amortization	23,925	23,002
Stock-based compensation	15,233	9,023
Provision for excess and obsolete inventory	10,039	3,800
Deferred taxes	12,699	-6,183
Other	-141	-987
Changes in operating assets and liabilities:	'	'
Accounts receivable	-58,882	-13,191
Inventories	2,635	-4,040
Prepayments and other assets	-628	-1,070
Accounts payable and other accrued expenses	-45,487	-47,404
Deferred revenue and customer advances	9,632	-10,000
Retirement plans contributions	-1,425	-1,063
Accrued income taxes	-9,609	-9,085
Net cash used for operating activities	-25,821	-36,494
Cash flows from investing activities:	'	'
Purchases of property, plant and equipment	-31,197	-22,547
Purchases of marketable securities	-257,260	-124,514
Proceeds from maturities of marketable securities	280,322	119,552
Proceeds from sales of marketable securities	101,363	21,694
Proceeds from life insurance	4,391	'
Net cash provided by (used for) investing activities	97,619	-5,815
Cash flows from financing activities:	'	'
Issuance of common stock under employee stock purchase and stock option plans	10,165	8,921
Payments of long-term debt	-190,975	'
Payments of contingent consideration	'	-313
Net cash (used for) provided by financing activities	-180,810	8,608
Decrease in cash and cash equivalents	-109,012	-33,701
Cash and cash equivalents at beginning of period	341,638	338,920
Cash and cash equivalents at end of period	$232,626	$305,219

The_Company

The Company	3 Months Ended
	Mar. 30, 2014
The Company	'
	A. The Company
	Teradyne, Inc. (the “Company” or “Teradyne”) is a leading global supplier of automatic test equipment. Teradyne’s automatic test equipment products and services include:
		•	semiconductor test (“Semiconductor Test”) systems;
		•	wireless test (“Wireless Test”) systems; and
		•	military/aerospace (“Mil/Aero”) test instrumentation and systems, storage test (“Storage Test”) systems, and circuit-board test and inspection (“Commercial Board Test”) systems (collectively these products represent “System Test”).

Accounting_Policies

Accounting Policies	3 Months Ended
	Mar. 30, 2014
Accounting Policies	'
	B. Accounting Policies
	Basis of Presentation
	The consolidated interim financial statements include the accounts of Teradyne and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated. These interim financial statements are unaudited and reflect all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of such interim financial statements. Certain prior year’s amounts were reclassified to conform to the current year presentation. The December 31, 2013 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America.
	The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 28, 2014, for the year ended December 31, 2013.
	Preparation of Financial Statements and Use of Estimates
	The preparation of consolidated financial statements requires management to make estimates and judgments that affect the amounts reported in the financial statements. Actual results may differ significantly from these estimates.

Recently_Issued_Accounting_Pro

Recently Issued Accounting Pronouncements	3 Months Ended
	Mar. 30, 2014
Recently Issued Accounting Pronouncements	'
	C. Recently Issued Accounting Pronouncements
	On July 18, 2013, the FASB issued ASU 2013-11, “Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists.” Under this ASU, unrecognized tax benefits will be netted against all available same-jurisdiction loss or other tax carryforwards that would be utilized, rather than only against carryforwards that are created by unrecognized tax benefits. The provisions of this ASU are effective for interim and annual periods beginning on or after December 15, 2013. Teradyne’s implementation during the three months ended March 30, 2014 of this ASU did not have a material impact on Teradyne’s financial position or results of operations.

Financial_Instruments_and_Deri

Financial Instruments and Derivatives	3 Months Ended
	Mar. 30, 2014
Financial Instruments and Derivatives	'
	D. Financial Instruments and Derivatives
	Cash Equivalents
	Teradyne considers all highly liquid investments with maturities of three months or less at the date of acquisition to be cash equivalents.
	Financial Instruments
	Teradyne accounts for its investments in debt and equity securities in accordance with the provisions of ASC 320-10, “Investments—Debt and Equity Securities.” ASC 320-10 requires that certain debt and equity securities be classified into one of three categories; trading, available-for-sale or held-to-maturity securities. As of March 30, 2014, Teradyne’s investments in debt and equity securities were classified as available-for-sale and recorded at their fair market value.
	On a quarterly basis, Teradyne reviews its investments to identify and evaluate those that have an indication of a potential other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include:
		•		The length of time and the extent to which the market value has been less than cost;
		•		The financial condition and near-term prospects of the issuer; and
		•		The intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value.
	Teradyne uses the market and income approach techniques to value its financial instruments and there were no changes in valuation techniques during the three months ended March 30, 2014. As defined in ASC 820-10 “Fair Value Measurements and Disclosures”, fair value is the price that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. ASC 820-10 requires that assets and liabilities carried at fair value be classified and disclosed in one of the following three categories:
	Level 1: Quoted prices in active markets for identical assets as of the reporting date.
	Level 2: Inputs other than Level 1, that are observable either directly or indirectly as of the reporting date. For example, a common approach for valuing fixed income securities is the use of matrix pricing. Matrix pricing is a mathematical technique used to value securities by relying on the securities’ relationship to other benchmark quoted prices, and therefore is considered a Level 2 input.
	Level 3: Unobservable inputs that are not supported by market data. Unobservable inputs are developed based on the best information available, which might include Teradyne’s own data.
	Most of Teradyne’s fixed income securities are classified as Level 2, with the exception of U.S. Treasury securities and investments in equity and debt mutual funds, which are classified as Level 1, and contingent consideration, which is classified as Level 3. The majority of Level 2 securities are priced by third party pricing vendors. These pricing vendors utilize the most recent observable market information in pricing these securities or, if specific prices are not available, use other observable inputs like market transactions involving identical or comparable securities.
	There were no realized losses recorded in the three months ended March 30, 2014 and March 31, 2013. Realized gains recorded in the three months ended March 30, 2014 and March 31, 2013, were $0.3 million and $0.3 million, respectively. Realized gains are included in interest income.
	During the three months ended March 30, 2014 and March 31, 2013, there were no transfers in or out of Level 1, Level 2 or Level 3 financial instruments.
	The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of March 30, 2014 and December 31, 2013.
			March 30, 2014
			Quoted Prices				Significant				Significant			Total
			in Active				Other				Unobservable
			Markets for				Observable				Inputs
			Identical				Inputs				(Level 3)
			Instruments				(Level 2)
			(Level 1)
			(in thousands)
	Assets
	Cash		$	131,722			$	—			$	—		$	131,722
	Cash equivalents			87,894				13,010				—			100,904
	Available-for-sale securities:
	U.S. Treasury securities			321,296				—				—			321,296
	U.S. government agency securities			—				191,863				—			191,863
	Commercial paper			—				116,767				—			116,767
	Corporate debt securities			—				82,787				—			82,787
	Equity and debt mutual funds			14,171				—				—			14,171
	Certificates of deposit and time deposits			—				7,257				—			7,257
	Non-U.S. government securities			—				77				—			77
	Total			555,083				411,761				—			966,844
	Derivatives			—				209				—			209
	Total		$	555,083			$	411,970			$	—		$	967,053
	Liabilities
	Contingent consideration		$	—			$	—			$	2,230		$	2,230
	Total		$	—			$	—			$	2,230		$	2,230
	Reported as follows:
			(Level 1)				(Level 2)				(Level 3)			Total
			(in thousands)
	Assets
	Cash and cash equivalents		$	219,616			$	13,010			$	—		$	232,626
	Marketable securities			214,230				247,920				—			462,150
	Long-term marketable securities			121,237				150,831				—			272,068
	Other current assets			—				209				—			209
			$	555,083			$	411,970			$	—		$	967,053
	Liabilities
	Long-term other accrued liabilities		$	—			$	—			$	2,230		$	2,230
			$	—			$	—			$	2,230		$	2,230
			December 31, 2013
			Quoted Prices				Significant				Significant			Total
			in Active				Other				Unobservable
			Markets for				Observable				Inputs
			Identical				Inputs				(Level 3)
			Instruments				(Level 2)
			(Level 1)
			(in thousands)
	Assets
Cash		$	117,242			$	—			$	—		$	117,242
Cash equivalents			165,865				58,531				—			224,396
Available-for-sale securities:
U.S. Treasury securities			467,895				—				—			467,895
U.S. government agency securities			—				202,588				—			202,588
Commercial paper			—				105,598				—			105,598
Corporate debt securities			—				65,387				—			65,387
Equity and debt mutual funds			13,156				—				—			13,156
Certificates of deposit and time deposits			—				3,258				—			3,258
Non-U.S. government securities			—				78				—			78
Total			764,158				435,440				—			1,199,598
Derivatives			—				153				—			153
Total		$	764,158			$	435,593			$	—		$	1,199,751
Liabilities
Contingent consideration		$	—			$	—			$	2,230		$	2,230
Total		$	—			$	—			$	2,230		$	2,230
Reported as follows:
		(Level 1)				(Level 2)				(Level 3)			Total
		(in thousands)
Assets
Cash and cash equivalents		$	283,107			$	58,531			$	—		$	341,638
Marketable securities			371,101				215,781				—			586,882
Long-term marketable securities			109,950				161,128				—			271,078
Other current assets			—				153				—			153
		$	764,158			$	435,593			$	—		$	1,199,751
Liabilities
Long-term other accrued liabilities		$	—			$	—			$	2,230		$	2,230
		$	—			$	—			$	2,230		$	2,230
Contingent consideration relates to Teradyne’s acquisition of ZTEC on October 25, 2013. The total purchase price included $2.2 million in fair value of contingent consideration payable upon achievement of certain customer order and revenue targets through 2015. The maximum amount of contingent consideration that could be paid is $5.0 million. Based on the projected results for the acquisition, no value was assigned to the revenue component of the contingent consideration.
The valuation of the customer order component of the contingent consideration utilized the following assumptions: (1) probability of meeting each benchmark; (2) expected timing of meeting each benchmark; and (3) discount rate reflecting the risk associated with the expected payments. The probabilities and timing for each benchmark were estimated based on a review of the historical and projected results. A discount rate of 5.2 percent was selected based on the cost of debt for the business, as a significant portion of the risk in achieving the customer order contingent consideration was captured in the probabilities assigned to meeting each benchmark. There were no changes to the fair value of the contingent consideration during the three months ended March 30, 2014.
Changes in the fair value of Level 3 contingent consideration for the three months ended March 30, 2014 and March 31, 2013 were as follows:
		For the Three Months
		Ended March 30, 2014
		(in thousands)
Balance at December 31, 2013		$	2,230
Contingent consideration payments			—
Balance at March 30, 2014		$	2,230
		For the Three Months
		Ended March 31, 2013
		(in thousands)
Balance at December 31, 2012		$	388
Contingent consideration payments			(313	)
Balance at March 31, 2013		$	75
The carrying amounts and fair values of Teradyne’s financial instruments at March 30, 2014 and December 31, 2013 were as follows:
		March 30, 2014								December 31, 2013
		Carrying Value				Fair Value				Carrying Value			Fair Value
		(in thousands)
Cash and cash equivalents		$	232,626			$	232,626			$	341,638		$	341,638
Marketable securities			734,218				734,218				857,960			857,960
Convertible debt(1)			—				—				185,708			611,433
Japan loan			—				—				955			955
-1	The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion feature.
The fair values of cash and cash equivalents, accounts receivable, net and accounts payable approximate the carrying amount due to the short-term nature of these instruments.
The following tables summarize the composition of available-for-sale marketable securities at March 30, 2014 and December 31, 2013:
		March 30, 2014
		Available-for-Sale													Fair Market
															Value of
															Investment
															with  Unrealized
		Cost				Unrealized				Unrealized			Fair Market		Losses
						Gain				(Loss)			Value
		(in thousands)
U.S. Treasury securities		$	321,184			$	236			$	(124	)	$	321,296	$	23,205
U.S. government agency securities			191,856				92				(85	)		191,863		91,951
Commercial paper			116,758				13				(4	)		116,767		38,906
Corporate debt securities			81,913				1,337				(463	)		82,787		49,413
Equity and debt mutual funds			11,483				2,725				(37	)		14,171		810
Certificates of deposit and time deposits			7,257				—				—			7,257		—
Non-U.S. government securities			77				—				—			77		—
		$	730,528			$	4,403			$	(713	)	$	734,218	$	204,285
Reported as follows:
		Cost				Unrealized				Unrealized			Fair Market		Fair Market
						Gain				(Loss)			Value		Value of
															Investments
															with Unrealized
															Losses
		(in thousands)
Marketable securities		$	462,031			$	146			$	(27	)	$	462,150	$	99,303
Long-term marketable securities			268,497				4,257				(686	)		272,068		104,982
		$	730,528			$	4,403			$	(713	)	$	734,218	$	204,285
		December 31, 2013
		Available-for-Sale													Fair Market
															Value of
															Investments
															with  Unrealized
		Cost				Unrealized				Unrealized			Fair Market		Losses
						Gain				(Loss)			Value
		(in thousands)
U.S. Treasury securities		$	468,084			$	94			$	(283	)	$	467,895	$	108,212
U.S. government agency securities			202,573				75				(60	)		202,588		84,498
Commercial paper			105,583				16				(1	)		105,598		7,993
Corporate debt securities			65,747				762				(1,122	)		65,387		40,355
Equity and debt mutual funds			10,463				2,742				(49	)		13,156		702
Certificates of deposit and time deposits			3,258				—				—			3,258		—
Non-U.S. government securities			78				—				—			78		—
		$	855,786			$	3,689			$	(1,515	)	$	857,960	$	241,760
Reported as follows:
		Cost				Unrealized				Unrealized			Fair Market		Fair Market
						Gain				(Loss)			Value		Value of
															Investments
															with Unrealized
															Losses
		(in thousands)
Marketable securities		$	586,818			$	85			$	(21	)	$	586,882	$	137,670
Long-term marketable securities			268,968				3,604				(1,494	)		271,078		104,090
		$	855,786			$	3,689			$	(1,515	)	$	857,960	$	241,760
As of March 30, 2014, the fair market value of investments with unrealized losses was $204.3 million. Of this value, $0.9 million had unrealized losses greater than one year and $203.4 million had unrealized losses less than one year. As of December 31, 2013, the fair market value of investments with unrealized losses was $241.8 million. Of this value, $0.9 million had unrealized losses greater than one year and $240.9 million had unrealized losses less than one year.
The contractual maturities of investments held at March 30, 2014 were as follows:
		March 30, 2014
		Cost				Fair Market
						Value
		(in thousands)
Due within one year		$	462,031			$	462,150
Due after 1 year through 5 years			226,558				226,607
Due after 5 years through 10 years			5,854				5,954
Due after 10 years			24,602				25,336
Total		$	719,045			$	720,047
Contractual maturities of investments held at March 30, 2014 exclude equity and debt mutual funds 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 the monetary assets and liabilities denominated in foreign currencies.
The notional amount of foreign currency forward contracts was $66.8 million and $74.8 million at March 30, 2014 and December 31, 2013, respectively.
The fair value of the outstanding contracts was a gain of $0.2 million and $0.2 million at March 30, 2014 and December 31, 2013, respectively. The following table summarizes the fair value of derivative instruments at March 30, 2014 and December 31, 2013:
		Balance Sheet Location				March 30,				December 31,
						2014				2013
						(in thousands)
Derivatives not designated as hedging instruments:
Foreign currency forward contracts			Other current assets			$	209			$	153
						$	209			$	153
Teradyne had no offsetting foreign exchange contracts at March 30, 2014 and December 31, 2013.
In the three months ended March 30, 2014 and March 31, 2013, Teradyne recorded net realized losses of $0.7 million and net realized gains of $2.2 million, respectively, related to foreign currency forward contracts hedging net monetary positions. Gains and losses on foreign currency forward contracts and foreign currency remeasurement gains and losses on monetary assets and liabilities are included in interest expense and other.
The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three months ended March 30, 2014 and March 31, 2013. The table does not reflect the corresponding gains (losses) from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. For the three months ended March 30, 2014 and March 31, 2013, gains (losses) from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $0.6 million and $(2.8) million, respectively.
		Location of		For the Three
		(Losses) Gains		Months Ended
		Recognized in
		Statement
		of Operations		March 30,				March 31,
				2014				2013
				(in thousands)
Derivatives not designated as hedging instruments:
Foreign currency forward contracts		Interest expense		$	(747	)		$	2,248
		and other
				$	(747	)		$	2,248
See Note E: “Debt” regarding derivatives related to convertible senior notes.

Debt

Debt	3 Months Ended
	Mar. 30, 2014
Debt	'
	E. Debt
	Loan Agreement
	On March 31, 2009, Teradyne K.K., Teradyne’s wholly-owned subsidiary in Japan, entered into a loan agreement with a local bank in Japan to borrow approximately $10.0 million (the loan was denominated in Japanese Yen). The loan had a term of 5 years and a fixed interest rate of 0.8%. Approximately $6.0 million of the loan was collateralized by a real estate mortgage on Teradyne K.K.’s building and land in Kumamoto, Japan and approximately $4.0 million was unsecured. Teradyne, Inc. guaranteed payment of the loan obligation. The loan was amortized over the term of the loan with semiannual principal payments of approximately $1.0 million on September 30 and March 30 each year. The final principal and interest payments were made during the three months ended March 30, 2014.
	Convertible Senior Notes
	In April 2009, Teradyne issued 4.50% convertible senior notes (the “Notes”) at an aggregate principal amount of $190 million and a conversion price of $5.4750 or 182.65 shares of Teradyne’s common stock per $1,000 principal amount of Notes. The Notes had a maturity date of March 15, 2014. Substantially all of the Notes were converted prior to March 15, 2014 and were “net share settled,” meaning that the holders received, for each $1,000 in principal amount of Notes, $1,000 in cash and approximately 131.95 shares of Teradyne common stock (calculated by taking 182.65 shares less 50.7 shares). The 50.7 shares were determined by dividing the $1,000 principal amount by the $19.74 average trading price of Teradyne’s common stock over the 25 day trading period from February 5, 2014 to March 12, 2014.
	Teradyne satisfied the Notes “net share settlement” by paying the aggregate principal amount of $190 million in cash and issuing 25.1 million shares of common stock. On March 13, 2014, Teradyne exercised its call option agreement entered into with Goldman, Sachs & Co. (the “hedge counterparty”) at the time of issuance of the Notes and received 25.1 million shares of Teradyne’s common stock, which were retired.
	The hedge counterparty will subsequently be able to exercise warrants with a strike price of $7.6650. These warrants will be net share settled, with approximately 534,000 warrants settled on a daily basis over a 65-day trading period from June 17, 2014 to September 17, 2014. However, Teradyne is not obligated to issue more than 34,526,500 shares of its common stock upon exercise of the warrants (which amount represented less than 19.99% of Teradyne’s outstanding shares of common stock as of March 31, 2009, without giving effect to any shares of common stock issuable pursuant to the warrant transaction).
	The tables below represent the components of Teradyne’s convertible senior notes:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Debt principal	$	—	$	189,998
	Unamortized debt discount		—		4,290
	Net carrying amount of the convertible debt	$	—	$	185,708
	The interest expense on Teradyne’s convertible senior notes for the three months ended March 30, 2014 and March 31, 2013 was as follows:
		For the Three Months
		Ended
		March 30,		March 31,
		2014		2013
		(in thousands)
	Contractual interest expense	$	1,757	$	2,137
	Amortization of the discount component and debt issue fees		4,493		3,957
	Total interest expense on the convertible debt	$	6,250	$	6,094

Prepayments

Prepayments	3 Months Ended
	Mar. 30, 2014
Prepayments	'
	F. Prepayments
	Prepayments consist of the following and are included in prepayments on the balance sheet:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Contract manufacturer prepayments	$	108,048	$	115,388
	Prepaid taxes		9,979		3,281
	Prepaid professional services		6,134		6,538
	Other prepayments		7,323		11,167
	Total prepayments	$	131,484	$	136,374

Deferred_Revenue_and_Customer_

Deferred Revenue and Customer Advances	3 Months Ended
	Mar. 30, 2014
Deferred Revenue and Customer Advances	'
	G. Deferred Revenue and Customer Advances
	Deferred revenue and customer advances consist of the following and are included in short and long-term deferred revenue and customer advances on the balance sheet:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Extended warranty	$	33,949	$	34,909
	Equipment maintenance and training		24,650		22,455
	Customer advances		9,940		4,825
	Undelivered elements		5,477		6,971
	Acceptance		4,776		—
	Total deferred revenue and customer advances	$	78,792	$	69,160

Product_Warranty

Product Warranty	3 Months Ended
	Mar. 30, 2014
Product Warranty	'
	H. Product Warranty
	Teradyne generally provides a one-year warranty on its products, commencing upon installation or shipment. A provision is recorded upon revenue recognition to cost of revenues for estimated warranty expense based on historical experience. Related costs are charged to the warranty accrual as incurred. The warranty balance below is included in other accrued liabilities on the balance sheet.
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Balance at beginning of period	$	6,660		$	9,786
	Accruals for warranties issued during the period		2,858			1,423
	Adjustments related to pre-existing warranties		(140	)		(929	)
	Settlements made during the period		(2,763	)		(3,205	)
	Balance at end of period	$	6,615		$	7,075
	When Teradyne receives revenue for extended warranty beyond one year, it is deferred and recognized on a straight-line basis over the contract period. Related costs are expensed as incurred. The extended warranty balance below is included in short and long-term deferred revenue and customer advances on the balance sheet.
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Balance at beginning of period	$	34,909		$	28,042
	Deferral of new extended warranty revenue		2,361			3,505
	Recognition of extended warranty deferred revenue		(3,321	)		(2,000	)
	Balance at end of period	$	33,949		$	29,547

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	5-May-14
Stock-Based Compensation	'
	I. Stock-Based Compensation
	In January 2014, Teradyne granted performance-based restricted stock units (“PRSUs”) to its executive officers with a performance metric based on relative total shareholder return (“TSR”). Teradyne’s three-year TSR performance will be measured against the Philadelphia Semiconductor Index, which consists of thirty companies in the semiconductor device and capital equipment industries. The final number of TSR PRSUs that vest will vary based upon the level of performance achieved from 200% of the target shares to 0% of the target shares. All TSR PRSUs will vest upon the three-year anniversary of the January 24, 2014 grant date. No TSR PRSUs will vest if the executive officer is no longer an employee at the end of the three-year period. The TSR PRSUs are valued using a Monte Carlo simulation model. The number of units expected to be earned, based upon the achievement of the TSR market condition, is factored into the grant date Monte Carlo valuation. Compensation expense is recognized on a straight-line basis over the three-year service period. Compensation expense is recognized regardless of the eventual number of units that are earned based upon the market condition, provided the executive officer remains an employee at the end of the three-year period. Compensation expense is reversed if the executive officer is not an employee at the end of the three-year service period. During the three months ended March 30, 2014, Teradyne granted 0.1 million TSR performance-based restricted stock unit awards with a grant date fair value of $22.06. The fair value was estimated using the Monte Carlo simulation model with the following assumptions:
		For the Three Months
		Ended
		March 30,
		2014
	Risk-free interest rate		0.75	%
	Teradyne volatility-historical		36.1	%
	Philadelphia Semiconductor Index volatility-historical		24.6	%
	Dividend yield		1.25	%
	Expected volatility was based on the historical volatility of Teradyne’s stock and the Philadelphia Semiconductor Index over the most recent three year period. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.24 per share divided by Teradyne’s January 24, 2014 stock price of $19.16.
	During the three months ended March 30, 2014, Teradyne granted 1.4 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $19.15 and 0.1 million of service-based stock options to executive officers at a weighted average grant date fair value of $5.49.
	During the three months ended March 31, 2013, Teradyne granted 1.6 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $16.57 and 0.2 million of service-based stock options to executive officers at a weighted average grant date fair value of $6.09.
	Restricted stock unit awards granted to employees vest in equal annual installments over four years. Stock options vest in equal annual installments over four years, and have a term of seven years from the date of grant.
	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
	Expected life (years)		4			4
	Risk-free interest rate		1.2	%		0.6	%
	Volatility-historical		38.8	%		46.8	%
	Dividend yield		1.25	%		0	%
	Teradyne determined the stock options’ expected life based upon historical exercise data for executive officers, the age of the executive officers and the terms of the stock option grant. Volatility was determined using historical volatility for a period equal to the expected life. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.24 per share divided by Teradyne’s January 24, 2014 stock price of $19.16.
	Effective January 31, 2014, Michael Bradley retired as Chief Executive Officer of Teradyne. Mr. Bradley will continue to serve on Teradyne’s Board of Directors. On January 22, 2014, Teradyne entered into an agreement (the “Retirement Agreement”) with Mr. Bradley. Under the Retirement Agreement, Mr. Bradley’s unvested restricted stock units and stock options granted prior to his retirement date will continue to vest in accordance with their terms through January 31, 2017; and any vested options or options that vest during that period may be exercised for the remainder of the applicable option term. In the Retirement Agreement, Mr. Bradley agreed to be bound by non-competition and non-solicitation restrictions through January 31, 2017. In the three months ended March 30, 2014, Teradyne recorded a one-time charge to stock-based compensation expense of $6.6 million related to the Retirement Agreement.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 30, 2014
Accumulated Other Comprehensive Income	'
	J. Accumulated Other Comprehensive Income
	Changes in accumulated other comprehensive income, which is presented net of tax, consist of the following:
			Unrealized Gains on			Retirement Plans			Total
			Marketable Securities			Prior Service Credit
			(in thousands)
	Balance at December 31, 2013, net of tax of $794, $(284)		$	1,381		$	2,619		$	4,000
	Other comprehensive income before reclassifications, net of tax of $654			1,139			—			1,139
	Amounts reclassified from accumulated other comprehensive income, net of tax of $(102), $(42)			(176	)		(73	)		(249	)
	Net current period other comprehensive income			963			(73	)		890
	Balance at March 30, 2014, net of tax of $1,346, $(326)		$	2,344		$	2,546		$	4,890
	Reclassifications out of accumulated other comprehensive income to the statement of operations for the three months ended March 30, 2014 and March 31, 2013, were as follows:
	Details about Accumulated		For the Three Months Ended						Affected Line Item
	Other Comprehensive Income								in the Statements
	Components								of Operations
			March 30,			March 31,
			2014			2013
			(in thousands)
	Available-for-sale marketable securities
	Unrealized gains, net of tax of $102, $83		$	176		$	144		Interest income
	Amortization of defined benefit pension and postretirement plans Prior service benefit, net of tax of $42, $40			73			69		(a)
	Total reclassifications, net of tax of $144, $123		$	249		$	213		Net income
	(a)	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note N: “Retirement Plans.”

Intangible_Assets

Intangible Assets	3 Months Ended
	Mar. 30, 2014
Intangible Assets	'
	K. Intangible Assets
	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet:
		March 30, 2014
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	362,126	$	206,551	$	155,575		6.3 years
	Customer relationships		146,276		86,333		59,943		8.0 years
	Trade names and trademarks		33,834		15,332		18,502		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	543,236	$	309,216	$	234,020		7.0 years
		December 31, 2013
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	362,126	$	193,756	$	168,370		6.3 years
	Customer relationships		146,276		81,742		64,534		8.0 years
	Trade names and trademarks		33,834		14,447		19,387		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	543,236	$	290,945	$	252,291		7.0 years
	Aggregate intangible asset amortization expense was $18.3 million and $18.0 million, respectively, for the three months ended March 30, 2014 and March 31, 2013. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows:
	Year	Amortization Expense
		(in thousands)
	2014 (remainder)	$	51,870
	2015		53,391
	2016		53,391
	2017		47,232
	2018		22,691

Net_Income_per_Common_Share

Net Income per Common Share	3 Months Ended
	Mar. 30, 2014
Net Income per Common Share	'
	L. 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
			March 30,		March 31,
			2014		2013
			(in thousands, except per
			share amounts)
	Net income for basic and diluted net income per share		$	929	$	6,589
	Weighted average common shares-basic			193,311		189,686
	Effect of dilutive potential common shares:
	Incremental shares from assumed conversion of convertible notes(1)			20,052		23,386
	Convertible note hedge warrant shares(2)			20,942		18,859
	Restricted stock units			1,051		1,123
	Stock options			1,106		1,676
	Employee stock purchase plan			22		27
	Dilutive potential common shares			43,173		45,071
	Weighted average common shares-diluted			236,484		234,757
	Net income per common share-basic		$	0	$	0.03
	Net income per common share-diluted		$	0	$	0.03
	-1	Incremental shares from conversion of the convertible notes for the three months ended March 30, 2014 were calculated using the difference between the average Teradyne stock price from January 1, 2014 through March 12, 2014 and the conversion price of $5.4750, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period from January 1, 2014 to March 12, 2014 and adjusted for the number of days the convertible notes were outstanding during the three months ended March 30, 2014. Incremental shares from assumed conversion of the convertible notes for the three months ended March 31, 2013 were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.4750, multiplied by the 34.7 million shares to be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
	-2	Convertible note hedge warrant shares for the three months ended March 30, 2014 and March 31, 2013 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, is divided by the average Teradyne stock price for the period.
	The computation of diluted net income per common share for the three months ended March 30, 2014 excludes the effect of the potential exercise of stock options to purchase approximately 0.4 million shares because the effect would have been anti-dilutive.
	The computation of diluted net income per common share for the three months ended March 31, 2013 excludes the effect of the potential exercise of stock options to purchase approximately 0.4 million shares because the effect would have been anti-dilutive.

Restructuring_and_Other

Restructuring and Other	3 Months Ended
	Mar. 30, 2014
Restructuring and Other	'
	M. Restructuring and Other
	Restructuring
	During the three months ended March 30, 2014, Teradyne recorded no restructuring charges. During the three months ended March 31, 2013, Teradyne recorded $0.4 million of severance charges related to headcount reductions in Semiconductor Test and System Test.
		Severance			Facility			Total
		and			Exit
		Benefits			Costs
		(in thousands)
	Pre-2013 Activities
	Balance at December 31, 2012	$	243		$	1,084		$	1,327
	Change in estimate		—			(553	)		(553	)
	Cash payments		(243	)		(531	)		(774	)
	Balance at December 31, 2013	$	—		$	—		$	—
	2013 Activities
	Q3 2013 Activity:
	Provision	$	1,337		$	—		$	1,337
	Cash payments		(966	)		—			(966	)
	Balance at December 31, 2013		371			—			371
	Cash payments		(161	)		—			(161	)
	Balance at March 30, 2014	$	210		$	—		$	210
	Q4 2013 Activity:
	Provision	$	600		$	—		$	600
	Cash payments		(486	)		—			(486	)
	Balance at December 31, 2013		114			—			114
	Cash payments		(114	)		—			(114	)
	Balance at March 30, 2014	$	—		$	—		$	—
	Balance at March 30, 2014	$	210		$	—		$	210
	The accrual balance for severance and benefits of $0.2 million is reflected in the accrued employees’ compensation and withholdings on the balance sheet and is expected to be paid by June 2014.

Retirement_Plans

Retirement Plans	3 Months Ended
	Mar. 30, 2014
Retirement Plans	'
	N. Retirement Plans
	ASC 715, “Compensation—Retirement Benefits” requires an employer with defined benefit plans or other postretirement benefit plans to recognize an asset or a liability on its balance sheet for the overfunded or underfunded status of the plans as defined by ASC 715. The pension asset or liability represents a difference between the fair value of the pension plan’s assets and the projected benefit obligation.
	Defined Benefit Pension Plans
	Teradyne has defined benefit pension plans covering a portion of domestic employees and employees of certain non-U.S. subsidiaries. Benefits under these plans are based on employees’ years of service and compensation. Teradyne’s funding policy is to make contributions to these plans in accordance with local laws and to the extent that such contributions are tax deductible. The assets of these plans consist primarily of fixed income and equity securities. In addition, Teradyne has an unfunded supplemental executive defined benefit plan in the United States to provide retirement benefits in excess of levels allowed by the Employment Retirement Income Security Act (“ERISA”) and the Internal Revenue Code (“IRC”), as well as unfunded foreign plans. In the three months ended March 31, 2014, Teradyne contributed $0.4 million to the U.S. supplemental executive defined benefit pension plan and $0.7 million to certain qualified plans for non-U.S. subsidiaries.
	For the three months ended March 30, 2014 and March 31, 2013, Teradyne’s net periodic pension cost was comprised of the following:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Service cost	$	796		$	834
	Interest cost		3,720			3,370
	Expected return on plan assets		(3,342	)		(3,630	)
	Amortization of unrecognized prior service cost		34			41
	Total net periodic pension cost	$	1,208		$	615
	Postretirement Benefit Plan
	In addition to receiving pension benefits, U.S. Teradyne employees who meet early retirement eligibility requirements as of their termination dates may participate in Teradyne’s Welfare Plan, which includes death, and medical and dental benefits up to age 65. Death benefits provide a fixed sum to retirees’ survivors and are available to all retirees. Substantially all of Teradyne’s current U.S. employees could become eligible for these benefits, and the existing benefit obligation relates primarily to those employees.
	For the three months ended March 30, 2014 and March 31, 2013, Teradyne’s net periodic postretirement benefit was comprised of the following:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Service cost	$	13		$	16
	Interest cost		86			87
	Amortization of unrecognized prior service benefit		(150	)		(150	)
	Total net periodic postretirement benefit	$	(51	)	$	(47	)

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 30, 2014
Commitments and Contingencies	'
	O. Commitments and Contingencies
	Purchase Commitments
	As of March 30, 2014, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments covered by the agreements aggregate to approximately $246.4 million, of which $236.5 million is for less than one year.
	Legal Claims
	Teradyne is subject to legal proceedings and claims which have arisen in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on Teradyne’s results of operations, financial condition or cash flows.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 30, 2014
Income Taxes	'
	P. Income Taxes
	The income tax benefit of $2.8 million for the three months ended March 30, 2014, included a $1.0 million discrete tax benefit related to disqualifying dispositions of incentive stock options and employee stock purchase plan shares and a $1.0 million discrete tax benefit related to the decrease in uncertain tax positions resulting from the change in positions and statute expiration. The income tax benefit of $8.0 million for the three months ended March 31, 2013, included an approximately $6.7 million discrete tax benefit related to the 2012 U.S. federal research and development tax credit retrospectively reinstated under the American Taxpayer Relief Act of 2012.
	The decrease in Teradyne’s income tax benefit for the three months ended March 30, 2014 compared to the three months ended March 31, 2013, was primarily attributable to the reinstatement of the U.S. research and development tax credit in 2013 for fiscal years 2012 and 2013. The U.S. research and development tax credit expired at the end of 2013.

Segment_Information

Segment Information	3 Months Ended
	Mar. 30, 2014
Segment Information	'
	Q. Segment Information
	Teradyne has three operating segments (Semiconductor Test, Wireless Test and System Test), which are its reportable segments. The Semiconductor Test segment includes operations related to the design, manufacturing and marketing of semiconductor test products and services. The Wireless Test segment includes operations related to design, manufacturing and marketing of wireless test products and services. The System Test segment includes operations related to design, manufacturing and marketing of products and services for military/aerospace instrumentation test, storage test and circuit-board test. Each operating segment has a segment manager who is directly accountable to and maintains regular contact with Teradyne’s chief operating decision maker (Teradyne’s chief executive officer) to discuss operating activities, financial results, forecasts, and plans for the segment.
	Teradyne evaluates performance based on several factors, of which the primary financial measure is business segment income before income taxes. The accounting policies of the business segments are the same as those described in Note B: “Accounting Policies” in Teradyne’s Annual Report on Form 10-K for the year ended December 31, 2013. Segment information is as follows:
			Semiconductor		Wireless			System		Corporate			Consolidated
			Test		Test			Test		and
										Eliminations
			(in thousands)
	Three months ended March 30, 2014:
	Net revenues		$	261,737	$	21,210		$	38,063	$	—		$	321,010
	Income (loss) before income taxes(1)(2)			34,600		(25,085	)		448		(11,836	)		(1,873	)
	Three months ended March 31, 2013:
	Net revenues		$	211,506	$	33,598		$	35,263	$	—		$	280,367
	Income (loss) before income taxes(1)(2)			13,766		(9,997	)		1,530		(6,725	)		(1,426	)
	-1	Interest income and interest expense and other are included in Corporate and Eliminations.
	-2	Included in the income (loss) before income taxes for each of the segments are charges and credits for the three months ended March 30, 2014 and March 31, 2013 that include restructuring and other, and provision for excess and obsolete inventory, as follows:
	Included in the Semiconductor Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	6,205	$	213
	Included in the Wireless Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	3,093	$	2,668
	Included in the System Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	741	$	919
	Restructuring and other			—		244
	Total		$	741	$	1,163

Shareholders_Equity

Shareholders' Equity	3 Months Ended
	Mar. 30, 2014
Shareholders' Equity	'
	R. Shareholders’ Equity
	Stock Repurchase Program
	In November 2010, Teradyne’s Board of Directors authorized a stock repurchase program for up to $200 million. In the three months ended March 30, 2014 and March 31, 2013, Teradyne did not repurchase any shares. Cumulatively, as of March 30, 2014, Teradyne has repurchased 2.6 million shares of common stock for $31.2 million at an average price of $11.84.
	Dividend
	In January 2014, Teradyne’s Board of Directors declared an initial quarterly cash dividend of $0.06 per share to be paid on June 2, 2014 to the stockholders of record as of May 9, 2014. Payment of future cash dividends will rest within the discretion of Teradyne’s Board of Directors and will depend, among other things, upon Teradyne’s earnings, capital requirements and financial condition.

Accounting_Policies_Policies

Accounting Policies (Policies)	3 Months Ended
	Mar. 30, 2014
Basis of Presentation	'
	Basis of Presentation
	The consolidated interim financial statements include the accounts of Teradyne and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated. These interim financial statements are unaudited and reflect all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of such interim financial statements. Certain prior year’s amounts were reclassified to conform to the current year presentation. The December 31, 2013 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America.
	The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in Teradyne’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (“SEC”) on February 28, 2014, for the year ended December 31, 2013.
Preparation of Financial Statements and Use of Estimates	'
	Preparation of Financial Statements and Use of Estimates
	The preparation of consolidated financial statements requires management to make estimates and judgments that affect the amounts reported in the financial statements. Actual results may differ significantly from these estimates.

Financial_Instruments_and_Deri1

Financial Instruments and Derivatives (Tables)	3 Months Ended
	Mar. 30, 2014
Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	'
	The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of March 30, 2014 and December 31, 2013.
			March 30, 2014
			Quoted Prices				Significant				Significant			Total
			in Active				Other				Unobservable
			Markets for				Observable				Inputs
			Identical				Inputs				(Level 3)
			Instruments				(Level 2)
			(Level 1)
			(in thousands)
	Assets
	Cash		$	131,722			$	—			$	—		$	131,722
	Cash equivalents			87,894				13,010				—			100,904
	Available-for-sale securities:
	U.S. Treasury securities			321,296				—				—			321,296
	U.S. government agency securities			—				191,863				—			191,863
	Commercial paper			—				116,767				—			116,767
	Corporate debt securities			—				82,787				—			82,787
	Equity and debt mutual funds			14,171				—				—			14,171
	Certificates of deposit and time deposits			—				7,257				—			7,257
	Non-U.S. government securities			—				77				—			77
	Total			555,083				411,761				—			966,844
	Derivatives			—				209				—			209
	Total		$	555,083			$	411,970			$	—		$	967,053
	Liabilities
	Contingent consideration		$	—			$	—			$	2,230		$	2,230
	Total		$	—			$	—			$	2,230		$	2,230
	Reported as follows:
			(Level 1)				(Level 2)				(Level 3)			Total
			(in thousands)
	Assets
	Cash and cash equivalents		$	219,616			$	13,010			$	—		$	232,626
	Marketable securities			214,230				247,920				—			462,150
	Long-term marketable securities			121,237				150,831				—			272,068
	Other current assets			—				209				—			209
			$	555,083			$	411,970			$	—		$	967,053
	Liabilities
	Long-term other accrued liabilities		$	—			$	—			$	2,230		$	2,230
			$	—			$	—			$	2,230		$	2,230
			December 31, 2013
			Quoted Prices				Significant				Significant			Total
			in Active				Other				Unobservable
			Markets for				Observable				Inputs
			Identical				Inputs				(Level 3)
			Instruments				(Level 2)
			(Level 1)
			(in thousands)
	Assets
	Cash		$	117,242			$	—			$	—		$	117,242
	Cash equivalents			165,865				58,531				—			224,396
	Available-for-sale securities:
	U.S. Treasury securities			467,895				—				—			467,895
	U.S. government agency securities			—				202,588				—			202,588
	Commercial paper			—				105,598				—			105,598
	Corporate debt securities			—				65,387				—			65,387
	Equity and debt mutual funds			13,156				—				—			13,156
	Certificates of deposit and time deposits			—				3,258				—			3,258
	Non-U.S. government securities			—				78				—			78
	Total			764,158				435,440				—			1,199,598
	Derivatives			—				153				—			153
	Total		$	764,158			$	435,593			$	—		$	1,199,751
	Liabilities
	Contingent consideration		$	—			$	—			$	2,230		$	2,230
	Total		$	—			$	—			$	2,230		$	2,230
Reported as follows:
		(Level 1)				(Level 2)				(Level 3)			Total
		(in thousands)
Assets
Cash and cash equivalents		$	283,107			$	58,531			$	—		$	341,638
Marketable securities			371,101				215,781				—			586,882
Long-term marketable securities			109,950				161,128				—			271,078
Other current assets			—				153				—			153
		$	764,158			$	435,593			$	—		$	1,199,751
Liabilities
Long-term other accrued liabilities		$	—			$	—			$	2,230		$	2,230
		$	—			$	—			$	2,230		$	2,230
Schedule of Changes in Fair Value of Level 3 Contingent Consideration	'
	Changes in the fair value of Level 3 contingent consideration for the three months ended March 30, 2014 and March 31, 2013 were as follows:
			For the Three Months
			Ended March 30, 2014
			(in thousands)
	Balance at December 31, 2013		$	2,230
	Contingent consideration payments			—
	Balance at March 30, 2014		$	2,230
			For the Three Months
			Ended March 31, 2013
			(in thousands)
	Balance at December 31, 2012		$	388
	Contingent consideration payments			(313	)
	Balance at March 31, 2013		$	75
Schedule of Carrying Amounts and Fair Values of Financial Instruments	'
	The carrying amounts and fair values of Teradyne’s financial instruments at March 30, 2014 and December 31, 2013 were as follows:
			March 30, 2014								December 31, 2013
			Carrying Value				Fair Value				Carrying Value			Fair Value
			(in thousands)
	Cash and cash equivalents		$	232,626			$	232,626			$	341,638		$	341,638
	Marketable securities			734,218				734,218				857,960			857,960
	Convertible debt(1)			—				—				185,708			611,433
	Japan loan			—				—				955			955
	-1	The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion feature.
Schedule of Available-for-Sale Marketable Securities	'
	The following tables summarize the composition of available-for-sale marketable securities at March 30, 2014 and December 31, 2013:
			March 30, 2014
			Available-for-Sale													Fair Market
																Value of
																Investment
																with  Unrealized
			Cost				Unrealized				Unrealized			Fair Market		Losses
							Gain				(Loss)			Value
			(in thousands)
	U.S. Treasury securities		$	321,184			$	236			$	(124	)	$	321,296	$	23,205
	U.S. government agency securities			191,856				92				(85	)		191,863		91,951
	Commercial paper			116,758				13				(4	)		116,767		38,906
	Corporate debt securities			81,913				1,337				(463	)		82,787		49,413
	Equity and debt mutual funds			11,483				2,725				(37	)		14,171		810
	Certificates of deposit and time deposits			7,257				—				—			7,257		—
	Non-U.S. government securities			77				—				—			77		—
			$	730,528			$	4,403			$	(713	)	$	734,218	$	204,285
	Reported as follows:
			Cost				Unrealized				Unrealized			Fair Market		Fair Market
							Gain				(Loss)			Value		Value of
																Investments
																with Unrealized
																Losses
			(in thousands)
	Marketable securities		$	462,031			$	146			$	(27	)	$	462,150	$	99,303
	Long-term marketable securities			268,497				4,257				(686	)		272,068		104,982
			$	730,528			$	4,403			$	(713	)	$	734,218	$	204,285
			December 31, 2013
			Available-for-Sale													Fair Market
																Value of
																Investments
																with  Unrealized
			Cost				Unrealized				Unrealized			Fair Market		Losses
							Gain				(Loss)			Value
			(in thousands)
	U.S. Treasury securities		$	468,084			$	94			$	(283	)	$	467,895	$	108,212
	U.S. government agency securities			202,573				75				(60	)		202,588		84,498
	Commercial paper			105,583				16				(1	)		105,598		7,993
	Corporate debt securities			65,747				762				(1,122	)		65,387		40,355
	Equity and debt mutual funds			10,463				2,742				(49	)		13,156		702
	Certificates of deposit and time deposits			3,258				—				—			3,258		—
	Non-U.S. government securities			78				—				—			78		—
			$	855,786			$	3,689			$	(1,515	)	$	857,960	$	241,760
	Reported as follows:
			Cost				Unrealized				Unrealized			Fair Market		Fair Market
							Gain				(Loss)			Value		Value of
																Investments
																with Unrealized
																Losses
			(in thousands)
	Marketable securities		$	586,818			$	85			$	(21	)	$	586,882	$	137,670
	Long-term marketable securities			268,968				3,604				(1,494	)		271,078		104,090
			$	855,786			$	3,689			$	(1,515	)	$	857,960	$	241,760
Contractual Maturities of Investments Held	'
	The contractual maturities of investments held at March 30, 2014 were as follows:
			March 30, 2014
			Cost				Fair Market
							Value
			(in thousands)
	Due within one year		$	462,031			$	462,150
	Due after 1 year through 5 years			226,558				226,607
	Due after 5 years through 10 years			5,854				5,954
	Due after 10 years			24,602				25,336
	Total		$	719,045			$	720,047
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	'
	The following table summarizes the fair value of derivative instruments at March 30, 2014 and December 31, 2013:
			Balance Sheet Location				March 30,				December 31,
							2014				2013
							(in thousands)
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts			Other current assets			$	209			$	153
							$	209			$	153
Schedule of Effect of Derivative Instruments on Statement of Operations Recognized	'
	The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three months ended March 30, 2014 and March 31, 2013. The table does not reflect the corresponding gains (losses) from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. For the three months ended March 30, 2014 and March 31, 2013, gains (losses) from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $0.6 million and $(2.8) million, respectively.
			Location of		For the Three
			(Losses) Gains		Months Ended
			Recognized in
			Statement
			of Operations		March 30,				March 31,
					2014				2013
					(in thousands)
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		Interest expense		$	(747	)		$	2,248
			and other
					$	(747	)		$	2,248

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 30, 2014
Components of Convertible Senior Notes	'
	The tables below represent the components of Teradyne’s convertible senior notes:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Debt principal	$	—	$	189,998
	Unamortized debt discount		—		4,290
	Net carrying amount of the convertible debt	$	—	$	185,708
Interest Expense on Convertible Senior Notes	'
	The interest expense on Teradyne’s convertible senior notes for the three months ended March 30, 2014 and March 31, 2013 was as follows:
		For the Three Months
		Ended
		March 30,		March 31,
		2014		2013
		(in thousands)
	Contractual interest expense	$	1,757	$	2,137
	Amortization of the discount component and debt issue fees		4,493		3,957
	Total interest expense on the convertible debt	$	6,250	$	6,094

Prepayments_Tables

Prepayments (Tables)	3 Months Ended
	Mar. 30, 2014
Schedule of Prepayments	'
	Prepayments consist of the following and are included in prepayments on the balance sheet:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Contract manufacturer prepayments	$	108,048	$	115,388
	Prepaid taxes		9,979		3,281
	Prepaid professional services		6,134		6,538
	Other prepayments		7,323		11,167
	Total prepayments	$	131,484	$	136,374

Deferred_Revenue_and_Customer_1

Deferred Revenue and Customer Advances (Tables)	3 Months Ended
	Mar. 30, 2014
Deferred Revenue and Customer Advances	'
	Deferred revenue and customer advances consist of the following and are included in short and long-term deferred revenue and customer advances on the balance sheet:
		March 30,		December 31,
		2014		2013
		(in thousands)
	Extended warranty	$	33,949	$	34,909
	Equipment maintenance and training		24,650		22,455
	Customer advances		9,940		4,825
	Undelivered elements		5,477		6,971
	Acceptance		4,776		—
	Total deferred revenue and customer advances	$	78,792	$	69,160

Product_Warranty_Tables

Product Warranty (Tables)	3 Months Ended
	Mar. 30, 2014
Other Accrued Liabilities	'
	The warranty balance below is included in other accrued liabilities on the balance sheet.
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Balance at beginning of period	$	6,660		$	9,786
	Accruals for warranties issued during the period		2,858			1,423
	Adjustments related to pre-existing warranties		(140	)		(929	)
	Settlements made during the period		(2,763	)		(3,205	)
	Balance at end of period	$	6,615		$	7,075
Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances	'
	The extended warranty balance below is included in short and long-term deferred revenue and customer advances on the balance sheet.
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Balance at beginning of period	$	34,909		$	28,042
	Deferral of new extended warranty revenue		2,361			3,505
	Recognition of extended warranty deferred revenue		(3,321	)		(2,000	)
	Balance at end of period	$	33,949		$	29,547

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	5-May-14
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions	'
	The fair value was estimated using the Monte Carlo simulation model with the following assumptions:
		For the Three Months
		Ended
		March 30,
		2014
	Risk-free interest rate		0.75	%
	Teradyne volatility-historical		36.1	%
	Philadelphia Semiconductor Index volatility-historical		24.6	%
	Dividend yield		1.25	%
Schedule of Estimated Fair Value of Stock Options Assumptions	'
	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
	Expected life (years)		4			4
	Risk-free interest rate		1.2	%		0.6	%
	Volatility-historical		38.8	%		46.8	%
	Dividend yield		1.25	%		0	%

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 30, 2014
Changes in Accumulated Other Comprehensive Income	'
	Changes in accumulated other comprehensive income, which is presented net of tax, consist of the following:
			Unrealized Gains on			Retirement Plans			Total
			Marketable Securities			Prior Service Credit
			(in thousands)
	Balance at December 31, 2013, net of tax of $794, $(284)		$	1,381		$	2,619		$	4,000
	Other comprehensive income before reclassifications, net of tax of $654			1,139			—			1,139
	Amounts reclassified from accumulated other comprehensive income, net of tax of $(102), $(42)			(176	)		(73	)		(249	)
	Net current period other comprehensive income			963			(73	)		890
	Balance at March 30, 2014, net of tax of $1,346, $(326)		$	2,344		$	2,546		$	4,890
Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations	'
	Reclassifications out of accumulated other comprehensive income to the statement of operations for the three months ended March 30, 2014 and March 31, 2013, were as follows:
	Details about Accumulated		For the Three Months Ended						Affected Line Item
	Other Comprehensive Income								in the Statements
	Components								of Operations
			March 30,			March 31,
			2014			2013
			(in thousands)
	Available-for-sale marketable securities
	Unrealized gains, net of tax of $102, $83		$	176		$	144		Interest income
	Amortization of defined benefit pension and postretirement plans Prior service benefit, net of tax of $42, $40			73			69		(a)
	Total reclassifications, net of tax of $144, $123		$	249		$	213		Net income
	(a)	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note N: “Retirement Plans.”

Intangible_Assets_Tables

Intangible Assets (Tables)	3 Months Ended
	Mar. 30, 2014
Schedule of Amortizable Intangible Assets	'
	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet:
		March 30, 2014
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	362,126	$	206,551	$	155,575		6.3 years
	Customer relationships		146,276		86,333		59,943		8.0 years
	Trade names and trademarks		33,834		15,332		18,502		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	543,236	$	309,216	$	234,020		7.0 years
		December 31, 2013
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	362,126	$	193,756	$	168,370		6.3 years
	Customer relationships		146,276		81,742		64,534		8.0 years
	Trade names and trademarks		33,834		14,447		19,387		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	543,236	$	290,945	$	252,291		7.0 years
Schedule of Estimated Intangible Asset Amortization Expense	'
	Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows:
	Year	Amortization Expense
		(in thousands)
	2014 (remainder)	$	51,870
	2015		53,391
	2016		53,391
	2017		47,232
	2018		22,691

Net_Income_per_Common_Share_Ta

Net Income per Common Share (Tables)	3 Months Ended
	Mar. 30, 2014
Computation of Basic and Diluted Net Income Per Common Share	'
	The following table sets forth the computation of basic and diluted net income per common share:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands, except per
			share amounts)
	Net income for basic and diluted net income per share		$	929	$	6,589
	Weighted average common shares-basic			193,311		189,686
	Effect of dilutive potential common shares:
	Incremental shares from assumed conversion of convertible notes(1)			20,052		23,386
	Convertible note hedge warrant shares(2)			20,942		18,859
	Restricted stock units			1,051		1,123
	Stock options			1,106		1,676
	Employee stock purchase plan			22		27
	Dilutive potential common shares			43,173		45,071
	Weighted average common shares-diluted			236,484		234,757
	Net income per common share-basic		$	0	$	0.03
	Net income per common share-diluted		$	0	$	0.03
	-1	Incremental shares from conversion of the convertible notes for the three months ended March 30, 2014 were calculated using the difference between the average Teradyne stock price from January 1, 2014 through March 12, 2014 and the conversion price of $5.4750, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period from January 1, 2014 to March 12, 2014 and adjusted for the number of days the convertible notes were outstanding during the three months ended March 30, 2014. Incremental shares from assumed conversion of the convertible notes for the three months ended March 31, 2013 were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.4750, multiplied by the 34.7 million shares to be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
	-2	Convertible note hedge warrant shares for the three months ended March 30, 2014 and March 31, 2013 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, is divided by the average Teradyne stock price for the period.

Restructuring_and_Other_Tables

Restructuring and Other (Tables)	3 Months Ended
	Mar. 30, 2014
Restructuring and Other	'
		Severance			Facility			Total
		and			Exit
		Benefits			Costs
		(in thousands)
	Pre-2013 Activities
	Balance at December 31, 2012	$	243		$	1,084		$	1,327
	Change in estimate		—			(553	)		(553	)
	Cash payments		(243	)		(531	)		(774	)
	Balance at December 31, 2013	$	—		$	—		$	—
	2013 Activities
	Q3 2013 Activity:
	Provision	$	1,337		$	—		$	1,337
	Cash payments		(966	)		—			(966	)
	Balance at December 31, 2013		371			—			371
	Cash payments		(161	)		—			(161	)
	Balance at March 30, 2014	$	210		$	—		$	210
	Q4 2013 Activity:
	Provision	$	600		$	—		$	600
	Cash payments		(486	)		—			(486	)
	Balance at December 31, 2013		114			—			114
	Cash payments		(114	)		—			(114	)
	Balance at March 30, 2014	$	—		$	—		$	—
	Balance at March 30, 2014	$	210		$	—		$	210

Retirement_Plans_Tables

Retirement Plans (Tables)	3 Months Ended
	Mar. 30, 2014
Postretirement Benefit Plans	'
Net Periodic Pension and Postretirement Cost (Benefit)	'
	For the three months ended March 30, 2014 and March 31, 2013, Teradyne’s net periodic postretirement benefit was comprised of the following:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Service cost	$	13		$	16
	Interest cost		86			87
	Amortization of unrecognized prior service benefit		(150	)		(150	)
	Total net periodic postretirement benefit	$	(51	)	$	(47	)
Defined Benefit Pension Plans	'
Net Periodic Pension and Postretirement Cost (Benefit)	'
	For the three months ended March 30, 2014 and March 31, 2013, Teradyne’s net periodic pension cost was comprised of the following:
		For the Three Months
		Ended
		March 30,			March 31,
		2014			2013
		(in thousands)
	Service cost	$	796		$	834
	Interest cost		3,720			3,370
	Expected return on plan assets		(3,342	)		(3,630	)
	Amortization of unrecognized prior service cost		34			41
	Total net periodic pension cost	$	1,208		$	615

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 30, 2014
Segment Information	'
	Segment information is as follows:
			Semiconductor		Wireless			System		Corporate			Consolidated
			Test		Test			Test		and
										Eliminations
			(in thousands)
	Three months ended March 30, 2014:
	Net revenues		$	261,737	$	21,210		$	38,063	$	—		$	321,010
	Income (loss) before income taxes(1)(2)			34,600		(25,085	)		448		(11,836	)		(1,873	)
	Three months ended March 31, 2013:
	Net revenues		$	211,506	$	33,598		$	35,263	$	—		$	280,367
	Income (loss) before income taxes(1)(2)			13,766		(9,997	)		1,530		(6,725	)		(1,426	)
	-1	Interest income and interest expense and other are included in Corporate and Eliminations.
	-2	Included in the income (loss) before income taxes for each of the segments are charges and credits for the three months ended March 30, 2014 and March 31, 2013 that include restructuring and other, and provision for excess and obsolete inventory, as follows:
Semiconductor Test	'
Schedule of Segment Reporting Information by Segment Charges	'
	Included in the Semiconductor Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	6,205	$	213
Wireless Test	'
Schedule of Segment Reporting Information by Segment Charges	'
	Included in the Wireless Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	3,093	$	2,668
System Test	'
Schedule of Segment Reporting Information by Segment Charges	'
	Included in the System Test segment are charges for the following:
			For the Three Months
			Ended
			March 30,		March 31,
			2014		2013
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	741	$	919
	Restructuring and other			—		244
	Total		$	741	$	1,163

Financial_Instruments_and_Deri2

Financial Instruments and Derivatives - Additional Information (Detail) (USD $)	3 Months Ended					3 Months Ended	12 Months Ended
	Mar. 30, 2014	Mar. 31, 2013	Dec. 31, 2013	Oct. 25, 2013	Oct. 25, 2013	Mar. 30, 2014	Dec. 31, 2013
				ZTEC Instruments, Inc.	ZTEC Instruments, Inc.	Foreign Currency Forward Contracts	Foreign Currency Forward Contracts
					Maximum
Financial Instruments and Fair Value [Line Items]	'	'	'	'	'	'	'
Available-for-sale securities, realized gain	$300,000	$300,000	'	'	'	'	'
Available-for-sale securities, realized losses	0	0	'	'	'	'	'
Contingent consideration	'	'	'	2,200,000	5,000,000	'	'
Contingent consideration discount rate	5.20%	'	'	'	'	'	'
Changes to fair value of contingent consideration	0	'	'	'	'	'	'
Fair market value of investments with unrealized losses	204,285,000	'	241,760,000	'	'	'	'
Fair market value of investments with unrealized losses greater than one year	900,000	'	900,000	'	'	'	'
Fair market value of investments with unrealized losses less than one year	203,400,000	'	240,900,000	'	'	'	'
Notional amount of foreign currency forward contracts	'	'	'	'	'	66,800,000	74,800,000
Gains (losses) on foreign currency transactions	600,000	-2,800,000	'	'	'	200,000	200,000
Realized (losses) gains on foreign currency contracts	($700,000)	$2,200,000	'	'	'	'	'

Schedule_of_Fair_Value_of_Fina

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	$734,218	$857,960
Derivatives	209	153
U.S. Treasury Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	321,296	467,895
U.S. Government Agency Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	191,863	202,588
Commercial Paper	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	116,767	105,598
Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	82,787	65,387
Equity And Debt Mutual Funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	14,171	13,156
Certificates of Deposit and Time Deposits	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	7,257	3,258
Non-U.S. Government Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	77	78
Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Derivatives	209	153
Total including derivatives	967,053	1,199,751
Contingent consideration	2,230	2,230
Liabilities	2,230	2,230
Fair Value, Measurements, Recurring | Cash	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	131,722	117,242
Fair Value, Measurements, Recurring | Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	100,904	224,396
Fair Value, Measurements, Recurring | U.S. Treasury Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	321,296	467,895
Fair Value, Measurements, Recurring | U.S. Government Agency Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	191,863	202,588
Fair Value, Measurements, Recurring | Commercial Paper	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	116,767	105,598
Fair Value, Measurements, Recurring | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	82,787	65,387
Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	14,171	13,156
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	7,257	3,258
Fair Value, Measurements, Recurring | Non-U.S. Government Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	77	78
Fair Value, Measurements, Recurring | Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	966,844	1,199,598
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 including derivatives	555,083	764,158
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	131,722	117,242
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	87,894	165,865
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | U.S. Treasury Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	321,296	467,895
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	14,171	13,156
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	555,083	764,158
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Derivatives	209	153
Total including derivatives	411,970	435,593
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	13,010	58,531
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	191,863	202,588
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	116,767	105,598
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	82,787	65,387
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	7,257	3,258
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	77	78
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	411,761	435,440
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Contingent consideration	2,230	2,230
Liabilities	$2,230	$2,230

Schedule_of_Reported_Financial

Schedule of Reported Financial Assets and Liabilities (Detail) (Fair Value, Measurements, Recurring, USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	$967,053	$1,199,751
Liabilities	2,230	2,230
Cash and Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	232,626	341,638
Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	462,150	586,882
Long-term marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	272,068	271,078
Other current assets	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	209	153
Long-term other accrued liabilities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	2,230	2,230
Quoted Prices in Active Markets for Identical Instruments (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	555,083	764,158
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	219,616	283,107
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	214,230	371,101
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	121,237	109,950
Significant Other Observable Inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	411,970	435,593
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	13,010	58,531
Significant Other Observable Inputs (Level 2) | Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	247,920	215,781
Significant Other Observable Inputs (Level 2) | Long-term marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	150,831	161,128
Significant Other Observable Inputs (Level 2) | Other current assets	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	209	153
Significant Unobservable Inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	2,230	2,230
Significant Unobservable Inputs (Level 3) | Long-term other accrued liabilities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	$2,230	$2,230

Schedule_of_Changes_in_Fair_Va

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Fair Value Measurements	'	'
Beginning Balance	$2,230	$388
Contingent consideration payments	'	-313
Ending Balance	$2,230	$75

Schedule_of_Carrying_Amounts_a

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013		Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2009
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'	'		'	'	'
Cash and cash equivalents, Carrying Value	$232,626	$341,638		$305,219	$338,920	'
Convertible debt, Carrying Value	'	185,708		'	'	'
Japan loan, Carrying Value	'	'		'	'	10,000
Carrying Value	'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'	'		'	'	'
Cash and cash equivalents, Carrying Value	232,626	341,638		'	'	'
Marketable securities, Carrying Value	734,218	857,960		'	'	'
Convertible debt, Carrying Value	'	185,708	[1]	'	'	'
Japan loan, Carrying Value	'	955		'	'	'
Fair Value	'	'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'	'		'	'	'
Cash and cash equivalents, Fair Value	232,626	341,638		'	'	'
Marketable securities, Fair Value	734,218	857,960		'	'	'
Convertible debt, Fair Value	'	611,433	[1]	'	'	'
Japan loan, Fair Value	'	$955		'	'	'
[1]	The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion feature.

Schedule_of_Available_for_Sale

Schedule of Available for Sale Marketable Securities (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	$730,528	$855,786
Available-for-sale marketable securities, Unrealized Gain	4,403	3,689
Available-for-sale marketable securities, Unrealized (Loss)	-713	-1,515
Available-for-sale marketable securities, Fair Market Value	734,218	857,960
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	204,285	241,760
U.S. Government Agency Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	191,856	202,573
Available-for-sale marketable securities, Unrealized Gain	92	75
Available-for-sale marketable securities, Unrealized (Loss)	-85	-60
Available-for-sale marketable securities, Fair Market Value	191,863	202,588
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	91,951	84,498
U.S. Treasury Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	321,184	468,084
Available-for-sale marketable securities, Unrealized Gain	236	94
Available-for-sale marketable securities, Unrealized (Loss)	-124	-283
Available-for-sale marketable securities, Fair Market Value	321,296	467,895
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	23,205	108,212
Commercial Paper	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	116,758	105,583
Available-for-sale marketable securities, Unrealized Gain	13	16
Available-for-sale marketable securities, Unrealized (Loss)	-4	-1
Available-for-sale marketable securities, Fair Market Value	116,767	105,598
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	38,906	7,993
Corporate Debt Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	81,913	65,747
Available-for-sale marketable securities, Unrealized Gain	1,337	762
Available-for-sale marketable securities, Unrealized (Loss)	-463	-1,122
Available-for-sale marketable securities, Fair Market Value	82,787	65,387
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	49,413	40,355
Equity And Debt Mutual Funds	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	11,483	10,463
Available-for-sale marketable securities, Unrealized Gain	2,725	2,742
Available-for-sale marketable securities, Unrealized (Loss)	-37	-49
Available-for-sale marketable securities, Fair Market Value	14,171	13,156
Available-for-sale marketable securities, Fair Market Value of Investment with Unrealized Losses	810	702
Certificates of Deposit and Time Deposits	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	7,257	3,258
Available-for-sale marketable securities, Fair Market Value	7,257	3,258
Non-U.S. Government Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	77	78
Available-for-sale marketable securities, Fair Market Value	$77	$78

Schedule_of_Reported_Available

Schedule of Reported Available for Sale Marketable Securities (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	$730,528	$855,786
Available-for-sale marketable securities, Unrealized Gain	4,403	3,689
Available-for-sale marketable securities, Unrealized (Loss)	-713	-1,515
Available-for-sale marketable securities, Fair Market Value	734,218	857,960
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	204,285	241,760
Marketable securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	462,031	586,818
Available-for-sale marketable securities, Unrealized Gain	146	85
Available-for-sale marketable securities, Unrealized (Loss)	-27	-21
Available-for-sale marketable securities, Fair Market Value	462,150	586,882
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	99,303	137,670
Long-term marketable securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	268,497	268,968
Available-for-sale marketable securities, Unrealized Gain	4,257	3,604
Available-for-sale marketable securities, Unrealized (Loss)	-686	-1,494
Available-for-sale marketable securities, Fair Market Value	272,068	271,078
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$104,982	$104,090

Contractual_Maturities_of_Inve

Contractual Maturities of Investments Held (Detail) (USD $)	Mar. 30, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'
Due within one year, cost	$462,031
Due after 1 year through 5 years, cost	226,558
Due after 5 years through 10 years, cost	5,854
Due after 10 years, cost	24,602
Total, cost	719,045
Due within one year, fair value	462,150
Due after 1 year through 5 years, fair value	226,607
Due after 5 years through 10 years, fair value	5,954
Due after 10 years, fair value	25,336
Total, fair value	$720,047

Schedule_of_Effect_of_Derivati

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013	Dec. 31, 2013
Fair Value, Option, Quantitative Disclosures	'	'	'
Derivatives asset not designated as hedging instruments	$209	'	$153
Foreign currency forward contracts derivatives not designated as hedging instruments, (Losses) Gains Recognized in Statement of Operations	-747	2,248	'
Interest Expense and Other	'	'	'
Fair Value, Option, Quantitative Disclosures	'	'	'
Foreign currency forward contracts derivatives not designated as hedging instruments, (Losses) Gains Recognized in Statement of Operations	-747	2,248	'
Not Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other current assets	'	'	'
Fair Value, Option, Quantitative Disclosures	'	'	'
Derivatives asset not designated as hedging instruments	$209	'	$153

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended			1 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2009	Mar. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Mar. 31, 2009	Mar. 30, 2014	Apr. 30, 2009	Mar. 30, 2014
					Maximum	Maximum	4.50% Convertible Senior Notes Due March 15, 2014	4.50% Convertible Senior Notes Due March 15, 2014
Debt Instrument	'	'	'	'	'	'	'	'
Borrowings from local bank	$10,000,000	'	'	'	'	'	'	'
Term of loan, years	'5 years	'	'	'	'	'	'	'
Debt instrument, interest rate, stated percentage	0.80%	'	'	'	'	'	4.50%	'
Loan collateralized by real estate mortgage	6,000,000	'	'	'	'	'	'	'
Unsecured loan	4,000,000	'	'	'	'	'	'	'
Semiannual principal payments of loan	'	1,000,000	1,000,000	'	'	'	'	'
Aggregate principal amount	'	'	'	189,998,000	'	'	190,000,000	'
Initial debt conversion price	'	'	'	'	'	'	$5.47	'
Conversion rate in number of shares	'	'	'	'	'	'	182.65	131.95
Additional aggregate principal amount	'	'	'	'	'	'	1,000	'
Senior notes maturity date	'	'	'	'	'	'	15-Mar-14	'
Number of shares excluded for conversion rate calculation	'	'	'	'	'	'	'	50.7
Trading days used to determine average price per share	'	'	'	'	'	'	'	'25 days
Average trading price of common shares	'	'	'	'	'	'	'	$19.74
Payments of long-term debt	'	$190,975,000	'	'	'	'	'	$190,000,000
Stock issued in conversion of notes	'	'	'	'	'	'	'	25,100,000
Stock received and retired	'	'	'	'	'	'	'	25,100,000
Strike price per share of warrant	'	$7.67	'	'	'	'	'	'
Warrants settled on a daily basis	'	534,000	'	'	'	'	'	'
Warrant settlement period	'	'65 days	'	'	'	'	'	'
Common stock shares issuable upon exercise of the warrants	'	'	'	'	'	34,526,500	'	'
Percentage of warrant price in excess of closing price of common stock	'	'	'	'	19.99%	'	'	'

Components_of_Convertible_Seni

Components of Convertible Senior Notes (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument	'	'
Debt principal	'	$189,998
Unamortized debt discount	'	4,290
Net carrying amount of the convertible debt	'	$185,708

Interest_Expense_on_Convertibl

Interest Expense on Convertible Senior Notes (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Debt Instrument	'	'
Contractual interest expense	$1,757	$2,137
Amortization of the discount component and debt issue fees	4,493	3,957
Total interest expense on the convertible debt	$6,250	$6,094

Schedule_of_Prepayments_Detail

Schedule of Prepayments (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Prepaid Expenses [Line Items]	'	'
Contract manufacturer prepayments	$108,048	$115,388
Prepaid taxes	9,979	3,281
Prepaid professional services	6,134	6,538
Other prepayments	7,323	11,167
Prepayments	$131,484	$136,374

Deferred_Revenue_and_Customer_2

Deferred Revenue and Customer Advances (Detail) (USD $)	Mar. 30, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Revenue Arrangement	'	'	'	'
Extended warranty	$33,949	$34,909	$29,547	$28,042
Equipment maintenance and training	24,650	22,455	'	'
Customer advances	9,940	4,825	'	'
Undelivered elements	5,477	6,971	'	'
Acceptance	4,776	'	'	'
Total deferred revenue and customer advances	$78,792	$69,160	'	'

Warranty_Accrual_Included_in_O

Warranty Accrual Included in Other Accrued Liabilities (Detail) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Schedule of Accrued Liabilities [Line Items]	'	'
Balance at beginning of period	$6,660	$9,786
Accruals for warranties issued during the period	2,858	1,423
Adjustments related to pre-existing warranties	-140	-929
Settlements made during the period	-2,763	-3,205
Balance at end of period	$6,615	$7,075

Extended_Product_Warranty_Incl

Extended Product Warranty Included in Short and Long-Term Deferred Revenue and Customer Advances (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Schedule of Accrued Liabilities [Line Items]	'	'
Balance at beginning of period	$34,909	$28,042
Deferral of new extended warranty revenue	2,361	3,505
Recognition of extended warranty deferred revenue	-3,321	-2,000
Balance at end of period	$33,949	$29,547

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

Share data in Millions, except Per Share data, unless otherwise specified

Mar. 30, 2014

Mar. 31, 2013

Mar. 30, 2014

Mar. 31, 2013

Mar. 30, 2014

Mar. 30, 2014

Jan. 24, 2014

Jan. 31, 2014

Mar. 30, 2014

Jan. 24, 2014

Jan. 31, 2014

Jan. 31, 2014

Service-Based Restricted Stock Units

Service-Based Restricted Stock Units

Restricted Stock Units

Stock Options

Stock Options

TSR Performance-Based Restricted Stock Units

TSR Performance-Based Restricted Stock Units

TSR Performance-Based Restricted Stock Units

TSR Performance-Based Restricted Stock Units

TSR Performance-Based Restricted Stock Units

Employees

Maximum

Minimum

Share-based Compensation Arrangement by Share-based Payment Award

'

'

'

'

'

'

'

'

'

'

'

'

Total shareholder return performance measurement period

'

'

'

'

'

'

'

'3 years

'

'

'

'

Percentage of vesting of target shares upon performance achieved

'

'

'

'

'

'

'

'

'

'

200.00%

0.00%

Restricted stock unit awards to employees

'

'

1.4

1.6

'

'

'

'

0.1

'

'

'

Weighted average grant date fair value of restricted stock units granted

'

'

$19.15

$16.57

'

'

'

'

$22.06

'

'

'

Estimated annual dividend amount per share

'

'

'

'

'

$0.24

'

'

$0.24

'

'

'

Stock price

'

'

'

'

'

'

$19.16

'

'

$19.16

'

'

Number of service-based stock options granted to executive officers

0.1

0.2

'

'

'

'

'

'

'

'

'

'

Weighted average grant date fair value of stock options granted to executive officers

$5.49

$6.09

'

'

'

'

'

'

'

'

'

'

Period of stock granted to employees and executive officers vest in equal installments

'

'

'

'

'4 years

'4 years

'

'

'

'

'

'

Stock options term

'7 years

'

'

'

'

'

'

'

'

'

'

'

Stock based compensation expense related to retirement agreement

$6,600,000

'

'

'

'

'

'

'

'

'

'

'

Schedule_of_Estimated_Fair_Val

Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions (Detail) (TSR Performance-Based Restricted Stock Units)	3 Months Ended
	Mar. 30, 2014
TSR Performance-Based Restricted Stock Units	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Risk-free interest rate	0.75%
Teradyne volatility-historical	36.10%
Philadelphia Semiconductor Index volatility-historical	24.60%
Dividend yield	1.25%

Schedule_of_Estimated_Fair_Val1

Schedule of Estimated Fair Value of Stock Options Assumptions (Detail) (Stock Options)	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Stock Options	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'
Expected life (years)	'4 years	'4 years
Risk-free interest rate	1.20%	0.60%
Volatility-historical	38.80%	46.80%
Dividend yield	1.25%	0.00%

Changes_in_Accumulated_Other_C

Changes in Accumulated Other Comprehensive Income Balances (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Beginning balance	$4,000	'
Other comprehensive income before reclassifications, net of tax	1,139	'
Amounts reclassified from accumulated other comprehensive income, net of tax	-249	-213
Other comprehensive income (loss)	890	-13
Ending balance	4,890	'
Unrealized Gains on Marketable Securities	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Beginning balance	1,381	'
Other comprehensive income before reclassifications, net of tax	1,139	'
Amounts reclassified from accumulated other comprehensive income, net of tax	-176	'
Other comprehensive income (loss)	963	'
Ending balance	2,344	'
Retirement Plans Prior Service Benefit	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Beginning balance	2,619	'
Amounts reclassified from accumulated other comprehensive income, net of tax	-73	'
Other comprehensive income (loss)	-73	'
Ending balance	$2,546	'

Changes_in_Accumulated_Other_C1

Changes in Accumulated Other Comprehensive Income Balances (Parenthetical) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income before reclassifications, tax	$654	$115	'
Amounts reclassified from accumulated other comprehensive income, tax	-102	-83	'
Amounts reclassified from accumulated other comprehensive income, tax	-42	-40	'
Unrealized gains on marketable securities, tax	1,346	'	794
Retirement plans prior service benefit, tax	-326	'	-284
Unrealized Gains on Marketable Securities	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income before reclassifications, tax	654	'	'
Amounts reclassified from accumulated other comprehensive income, tax	-102	'	'
Retirement Plans Prior Service Benefit	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Amounts reclassified from accumulated other comprehensive income, tax	($42)	'	'

Reclassification_Out_of_Accumu

Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014		Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'		'
Unrealized gains	$176		$144
Prior service benefit	73	[1]	69	[1]
Total reclassifications	$249		$213
[1]	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note N: "Retirement Plans."

Reclassification_Out_of_Accumu1

Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Parenthetical) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Unrealized gains, tax	$102	$83
Prior service benefit, tax	42	40
Total reclassifications, tax	$144	$123

Schedule_of_Amortizable_Intang

Schedule of Amortizable Intangible Assets (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	$543,236	$543,236
Accumulated Amortization	309,216	290,945
Net Carrying Amount	234,020	252,291
Weighted Average Useful Life, years	'7 years	'7 years
Developed technology	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	362,126	362,126
Accumulated Amortization	206,551	193,756
Net Carrying Amount	155,575	168,370
Weighted Average Useful Life, years	'6 years 3 months 18 days	'6 years 3 months 18 days
Customer Relationships	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	146,276	146,276
Accumulated Amortization	86,333	81,742
Net Carrying Amount	59,943	64,534
Weighted Average Useful Life, years	'8 years	'8 years
Trade names and trademarks	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	33,834	33,834
Accumulated Amortization	15,332	14,447
Net Carrying Amount	18,502	19,387
Weighted Average Useful Life, years	'9 years	'9 years
Customer backlog	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	$1,000	$1,000
Weighted Average Useful Life, years	'4 months 24 days	'4 months 24 days

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Goodwill and Intangible Assets Disclosure [Line Items]	'	'
Aggregate intangible asset amortization expense	$18,271	$18,036

Schedule_of_Estimated_Intangib

Schedule of Estimated Intangible Asset Amortization Expense (Detail) (USD $)	Mar. 30, 2014
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets	'
2014 (remainder)	$51,870
2015	53,391
2016	53,391
2017	47,232
2018	$22,691

Computation_of_Basic_and_Dilut

Computation of Basic and Diluted Net Income Per Common Share (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 30, 2014		Mar. 31, 2013
Net Income Loss Per Common Share	'		'
Net income for basic and diluted net income per share	$929		$6,589
Weighted average common shares-basic	193,311		189,686
Incremental shares from assumed conversion of convertible notes	20,052	[1]	23,386	[1]
Convertible note hedge warrant shares	20,942	[2]	18,859	[2]
Employee stock purchase plan	22		27
Dilutive potential common shares	43,173		45,071
Weighted average common shares-diluted	236,484		234,757
Net income per common share-basic	$0		$0.03
Net income per common share-diluted	$0		$0.03
Restricted Stock Units	'		'
Net Income Loss Per Common Share	'		'
Incremental shares attributable to share based payment arrangements	1,051		1,123
Stock Option	'		'
Net Income Loss Per Common Share	'		'
Incremental shares attributable to share based payment arrangements	1,106		1,676
[1]	Incremental shares from conversion of the convertible notes for the three months ended March 30, 2014 were calculated using the difference between the average Teradyne stock price from January 1, 2014 through March 12, 2014 and the conversion price of $5.4750, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period from January 1, 2014 to March 12, 2014 and adjusted for the number of days the convertible notes were outstanding during the three months ended March 30, 2014. Incremental shares from assumed conversion of the convertible notes for the three months ended March 31, 2013 were calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.4750, multiplied by the 34.7 million shares to be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
[2]	Convertible note hedge warrant shares for the three months ended March 30, 2014 and March 31, 2013 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.6650, multiplied by 34.7 million shares. The result of this calculation, representing the total intrinsic value of the warrant, is divided by the average Teradyne stock price for the period.

Computation_of_Basic_and_Dilut1

Computation of Basic and Diluted Net Income Per Common Share (Parenthetical) (Detail) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Convertible Notes	'	'
Net Income Loss Per Common Share	'	'
Initial debt conversion price	$5.47	$5.47
Shares that would be issued upon conversion	34.7	34.7
Convertible Notes Hedge Warrant	'	'
Net Income Loss Per Common Share	'	'
Initial debt conversion price	$7.67	$7.67
Shares that would be issued upon conversion	34.7	34.7

Net_Income_Per_Common_Share_Ad

Net Income Per Common Share - Additional Information (Detail)	3 Months Ended
In Millions, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Net Income Loss Per Common Share	'	'
Exercise of stock options	0.4	0.4

Restructuring_and_Other_Additi

Restructuring and Other - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
		System Test and Semiconductor Test
Restructuring Cost and Reserve	'	'
Restructuring charges	$0	'
Severance benefit and charges	'	400,000
Accrual balance for severance and benefits	$210,000	'

Schedule_of_Restructuring_and_

Schedule of Restructuring and Other Net (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Restructuring Cost and Reserve	'	'
Provision	$0	'
Ending balance	210	'
Pre-2013 Activities	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	'	1,327
Change in estimate	'	-553
Cash payments	'	-774
Ending balance	'	'
Q3 2013 Activity	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	371	'
Provision	'	1,337
Cash payments	-161	-966
Ending balance	210	371
Q4 2013 Activity	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	114	'
Provision	'	600
Cash payments	-114	-486
Ending balance	'	114
Severance and Benefits	'	'
Restructuring Cost and Reserve	'	'
Ending balance	210	'
Severance and Benefits | Pre-2013 Activities	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	'	243
Cash payments	'	-243
Ending balance	'	'
Severance and Benefits | Q3 2013 Activity	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	371	'
Provision	'	1,337
Cash payments	-161	-966
Ending balance	210	371
Severance and Benefits | Q4 2013 Activity	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	114	'
Provision	'	600
Cash payments	-114	-486
Ending balance	'	114
Facility Exit Costs | Pre-2013 Activities	'	'
Restructuring Cost and Reserve	'	'
Beginning Balance	'	1,084
Change in estimate	'	-553
Cash payments	'	-531
Ending balance	'	'

Retirement_Plans_Additional_In

Retirement Plans - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 30, 2014
U.S. Supplemental Executive Defined Benefit Pension Plan	'
Defined Benefit Plan Disclosure	'
Contribution to defined benefit pension plans	$0.40
Foreign Pension Plans, Defined Benefit	'
Defined Benefit Plan Disclosure	'
Contribution to defined benefit pension plans	$0.70

Schedule_of_Net_Periodic_Pensi

Schedule of Net Periodic Pension and Postretirement Cost (Benefit) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Defined Benefit Pension Plans	'	'
Defined Benefit Plan Disclosure	'	'
Service cost	$796	$834
Interest cost	3,720	3,370
Expected return on plan assets	-3,342	-3,630
Amortization of unrecognized prior service benefit	34	41
Total net periodic pension/ postretirement cost (benefit)	1,208	615
Postretirement Benefit Plans	'	'
Defined Benefit Plan Disclosure	'	'
Service cost	13	16
Interest cost	86	87
Amortization of unrecognized prior service benefit	-150	-150
Total net periodic pension/ postretirement cost (benefit)	($51)	($47)

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 30, 2014
Purchase Commitment, Excluding Long-term Commitment	'
Aggregate purchase commitments	246.4
Purchase commitments less than one year	236.5
Maximum	'
Purchase Commitment, Excluding Long-term Commitment	'
Purchase commitments period	'1 year

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Income Taxes [Line Items]	'	'
Income tax benefit	($2,802,000)	($8,015,000)
Discrete tax benefit related to disqualifying dispositions of incentive stock options and employee stock purchase plan shares	1,000,000	'
Discrete tax benefit related to decrease in uncertain tax positions	1,000,000	'
Discrete tax benefit related to the 2012 U.S. federal research and development tax credit	'	$6,700,000

Schedule_of_Segment_Informatio

Schedule of Segment Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]	'		'
Net revenues	$321,010		$280,367
Income (loss) before income taxes	-1,873	[1],[2]	-1,426	[1],[2]
Semiconductor Test	'		'
Segment Reporting Information [Line Items]	'		'
Net revenues	261,737		211,506
Income (loss) before income taxes	34,600	[1],[2]	13,766	[1],[2]
Wireless Test	'		'
Segment Reporting Information [Line Items]	'		'
Net revenues	21,210		33,598
Income (loss) before income taxes	-25,085	[1],[2]	-9,997	[1],[2]
System Test	'		'
Segment Reporting Information [Line Items]	'		'
Net revenues	38,063		35,263
Income (loss) before income taxes	448	[1],[2]	1,530	[1],[2]
Corporate And Eliminations	'		'
Segment Reporting Information [Line Items]	'		'
Income (loss) before income taxes	($11,836)	[1],[2]	($6,725)	[1],[2]
[1]	Interest income and interest expense and other are included in Corporate and Eliminations.
[2]	Included in the income (loss) before income taxes for each of the segments are charges and credits for the three months ended March 30, 2014 and March 31, 2013 that include restructuring and other, and provision for excess and obsolete inventory, as follows:

Schedule_of_Segment_Reporting_

Schedule of Segment Reporting Information by Segment Charges (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 30, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Restructuring and other	'	$332
Semiconductor Test	'	'
Segment Reporting Information [Line Items]	'	'
Cost of revenues-provision for excess and obsolete inventory	6,205	213
System Test	'	'
Segment Reporting Information [Line Items]	'	'
Cost of revenues-provision for excess and obsolete inventory	741	919
Restructuring and other	'	244
Total	741	1,163
Wireless Test	'	'
Segment Reporting Information [Line Items]	'	'
Cost of revenues-provision for excess and obsolete inventory	$3,093	$2,668

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		40 Months Ended	1 Months Ended
In Millions, except Per Share data, unless otherwise specified	Jan. 31, 2014	Mar. 30, 2014	Mar. 31, 2013	Mar. 30, 2014	Nov. 30, 2010
					Maximum
Stockholders Equity Note Disclosure [Line Items]	'	'	'	'	'
Stock repurchase program, authorized amount	'	'	'	'	$200
Repurchase of stock, shares	'	0	0	2.6	'
Repurchase of stock, value	'	'	'	$31.20	'
Common stock average price	'	'	'	$11.84	'
Dividends payable, amount per share	$0.06	'	'	'	'
Dividends payable, date to be paid	2-Jun-14	'	'	'	'
Dividends payable, record date	9-May-14	'	'	'	'