Teradyne (TER) 10-Q 8 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 29, 2013	Nov. 01, 2013
Document Information	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	29-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
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	'	191,611,017

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 29, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'		'
Cash and cash equivalents	$572,868		$338,920
Marketable securities	384,334		431,516
Accounts receivable, less allowance for doubtful accounts of $3,562 and $4,118 at September 29, 2013 and December 31, 2012, respectively	209,386		153,423
Inventories:	'		'
Parts	70,620		89,598
Assemblies in process	25,923		32,303
Finished goods	26,489		17,509
Inventory, Net, Total	123,032		139,410
Deferred tax assets	83,780		77,305
Prepayments	109,107		90,931
Other current assets	11,873		4,556
Total current assets	1,494,380		1,236,061
Net property, plant and equipment	275,421		265,782
Long-term marketable securities	202,087		235,872
Other assets	19,763		20,209
Retirement plans assets	5,020		3,282
Intangible assets, net	265,705		318,867
Goodwill	349,272		349,272
Total assets	2,611,648		2,429,345
Current liabilities:	'		'
Accounts payable	67,734		58,324
Accrued employees' compensation and withholdings	78,616		86,264
Deferred revenue and customer advances	70,367		81,357
Other accrued liabilities	62,184		57,249
Accrued income taxes	25,249		12,306
Current debt	183,573		2,328
Total current liabilities	487,723		297,828
Long-term deferred revenue and customer advances	17,455		16,227
Retirement plans liabilities	95,982		94,373
Deferred tax liabilities	37,632		50,201
Long-term other accrued liabilities	21,355		21,302
Long-term debt	'		171,059
Total liabilities	660,147		650,990
Commitments and contingencies (Note N)	'		'
SHAREHOLDERS' EQUITY	'		'
Common stock, $0.125 par value, 1,000,000 shares authorized, 191,399 shares and 187,908 shares issued and outstanding at September 29, 2013 and December 31, 2012, respectively	23,925		23,488
Additional paid-in capital	1,379,832		1,347,762
Accumulated other comprehensive income	3,855	[1]	5,820	[1]
Retained earnings	543,889		401,285
Total shareholders' equity	1,951,501		1,778,355
Total liabilities and shareholders' equity	$2,611,648		$2,429,345
[1]	Net of tax of $835 for unrealized gains on marketable securities and $(125) for retirement plans prior service credit.

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Accounts receivable, less allowance for doubtful accounts	$3,562	$4,118
Common stock, par value	$0.13	$0.13
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	191,399	187,908
Common stock, shares outstanding	191,399	187,908

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 29, 2013		Sep. 30, 2012		Sep. 29, 2013		Sep. 30, 2012
Net revenues:	'		'		'		'
Products	$365,825		$393,037		$943,212		$1,204,506
Services	67,551		70,357		199,420		203,840
Total net revenues	433,376		463,394		1,142,632		1,408,346
Cost of revenues:	'		'		'		'
Cost of products	150,365		169,782		405,569		550,282
Cost of services	28,717		33,412		88,119		97,432
Total cost of revenues	179,082		203,194		493,688		647,714
Gross profit	254,294		260,200		648,944		760,632
Operating expenses:	'		'		'		'
Engineering and development	68,918		63,946		199,442		193,059
Selling and administrative	72,917		69,030		210,037		207,727
Acquired intangible assets amortization	18,064		18,429		54,163		55,287
Restructuring and other	889		683		1,480		-7,404
Total operating expenses	160,788		152,088		465,122		448,669
Income from operations	93,506		108,112		183,822		311,963
Interest income	948		1,067		2,923		2,834
Interest expense and other	-6,902		-6,154		-20,262		-18,536
Income before income taxes	87,552	[1],[2]	103,025	[1],[2]	166,483	[1],[2]	296,261	[1],[2]
Income tax provision	18,093		14,384		23,879		62,669
Net income	$69,459		$88,641		$142,604		$233,592
Net income per common share:	'		'		'		'
Basic	$0.36		$0.47		$0.75		$1.25
Diluted	$0.29		$0.39		$0.61		$1.02
Weighted average common shares-basic	191,307		187,364		190,521		186,592
Weighted average common shares-diluted	235,828		229,210		235,165		230,003
[1]	Pension and post retirement actuarial gains and losses, 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 and nine months ended September 29, 2013 and September 30, 2012 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		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Net income	$69,459	$88,641	$142,604	$233,592
Other comprehensive income:	'	'	'	'
Net unrealized gains (losses) on marketable securities arising during period	887	1,259	-1,019	2,455
Less: Reclassification adjustment for net gains included in net income	-202	-93	-621	-583
Net change	685	1,166	-1,640	1,872
Defined benefit pension and post-retirement plans:	'	'	'	'
Amortization of prior service net benefit included in net periodic pension cost and post-retirement benefit	-109	-92	-325	-275
Other comprehensive income (loss)	576	1,074	-1,965	1,597
Comprehensive income	$70,035	$89,715	$140,639	$235,189

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net income	$142,604	$233,592
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	41,873	39,812
Amortization	69,495	67,366
Stock-based compensation	27,227	30,634
Provision for excess and obsolete inventory	9,616	16,408
Deferred taxes	-19,211	7,076
Non cash charge for the sale of inventories revalued at the date of acquisition	'	6,089
Contingent consideration adjustment	'	-8,373
Tax benefit related to stock options and restricted stock units	-807	-7,600
Retirement plans actuarial (gains) losses	-1,359	4,991
Impairment loss on property, plant and equipment	1,074	'
Other	83	-2,359
Changes in operating assets and liabilities:	'	'
Accounts receivable	-55,963	-76,134
Inventories	34,194	25,070
Prepayments and other assets	-26,312	7,278
Accounts payable and other accrued expenses	496	-17,600
Deferred revenue and customer advances	-9,762	-10,651
Retirement plans contributions	-3,569	-3,679
Accrued income taxes	13,750	50,313
Net cash provided by operating activities	223,429	362,233
Cash flows from investing activities:	'	'
Purchases of property, plant and equipment	-82,925	-91,132
Purchases of marketable securities	-657,188	-510,157
Proceeds from maturities of marketable securities	401,901	156,422
Proceeds from sales of marketable securities	332,597	14,250
Net cash used for investing activities	-5,615	-430,617
Cash flows from financing activities:	'	'
Issuance of common stock under employee stock option and stock purchase plans	16,778	17,959
Tax benefit related to stock options and restricted stock units	807	7,600
Payments of long-term debt	-1,063	-1,246
Payments of contingent consideration	-388	-43,973
Net cash provided by (used) for financing activities	16,134	-19,660
Increase (decrease) in cash and cash equivalents	233,948	-88,044
Cash and cash equivalents at beginning of period	338,920	573,736
Cash and cash equivalents at end of period	$572,868	$485,692

The_Company

The Company	9 Months Ended
	Sep. 29, 2013
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	9 Months Ended
	Sep. 29, 2013
Accounting Policies	'
	B. Accounting Policies
	Basis of Presentation
	The condensed 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, 2012 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. Security and Exchange Commission (“SEC”) on March 1, 2013, for the year ended December 31, 2012.
	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	9 Months Ended
	Sep. 29, 2013
Recently Issued Accounting Pronouncements	'
	C. Recently Issued Accounting Pronouncements
	In December 2011, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2011-11, “Disclosures about Offsetting Assets and Liabilities.” This ASU is intended to enhance the understanding of the effects of netting arrangements on an entity’s financial statements, including financial instruments and derivative instruments that are either offset or subject to a master netting arrangement. The scope of this ASU includes derivatives, sale and repurchase agreements, reverse sale and repurchase agreements, and securities borrowing and lending arrangements. The provisions of this ASU are effective for interim and annual periods beginning on or after January 1, 2013. Teradyne adopted this ASU effective January 1, 2013. See Note D “Financial Instruments and Derivatives.”
	In February 2013, the FASB issued ASU 2013-02, “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income” amending the disclosure requirements regarding the reporting of amounts reclassified out of accumulated other comprehensive income. The amendment does not change the current requirement for reporting net income or other comprehensive income, but requires additional disclosures about significant amounts reclassified out of accumulated other comprehensive income including the effect of the reclassification on the related statement of operations line items. The provisions of this ASU are effective for interim and annual periods beginning on or after January 1, 2013. Teradyne adopted this amendment effective January 1, 2013. See Note I “Accumulated Other Comprehensive Income.”
	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 does not expect this ASU to have a material impact on its financial position or results of operations.

Financial_Instruments_and_Deri

Financial Instruments and Derivatives	9 Months Ended
	Sep. 29, 2013
Financial Instruments and Derivatives	'
	D. Financial Instruments and Derivatives
	Financial Instruments
	Teradyne uses the market and income approach to value its financial instruments and there was no change in valuation techniques used by Teradyne during the three and nine months ended September 29, 2013 and September 30, 2012. 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 are carried at fair value and are classified 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.
	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 and nine months ended September 29, 2013 and September 30, 2012. Realized gains recorded in the three and nine months ended September 29, 2013, were $0.2 million and $0.5 million, respectively. Realized gains recorded in the three and nine months ended September 30, 2012, were $0.3 million and $0.9 million, respectively. Realized gains are included in interest income.
	During the nine months ended September 29, 2013 and September 30, 2012, 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 September 29, 2013 and December 31, 2012.
			September 29, 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		$	147,819			$	—			$	—			$	147,819
	Cash equivalents			417,823				7,226				—				425,049
	Available-for-sale securities:
	U.S. government agency securities			—				229,129				—				229,129
	U.S. Treasury securities			211,956				—				—				211,956
	Commercial paper			—				88,891				—				88,891
	Corporate debt securities			—				43,982				—				43,982
	Equity and debt mutual funds			12,122				—				—				12,122
	Certificates of deposit and time deposits			—				261				—				261
	Non-U.S. government securities			—				80				—				80
	Total			789,720				369,569				—				1,159,289
	Derivatives			—				276				—				276
	Total		$	789,720			$	369,845			$	—			$	1,159,565
	Reported as follows:
			(Level 1)				(Level 2)				(Level 3)				Total
			(in thousands)
	Assets
	Cash and cash equivalents		$	565,642			$	7,226			$	—			$	572,868
	Marketable securities			185,085				199,249				—				384,334
	Long-term marketable securities			38,993				163,094				—				202,087
	Other current assets			—				276				—				276
			$	789,720			$	369,845			$	—			$	1,159,565
			December 31, 2012
			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		$	139,354			$	—			$	—			$	139,354
	Cash equivalents			183,039				16,527				—				199,566
	Available-for-sale securities:
	U.S. Treasury securities			312,116				—				—				312,116
	U.S. government agency securities			—				217,655				—				217,655
	Commercial paper			—				70,434				—				70,434
	Corporate debt securities			—				55,755				—				55,755
	Equity and debt mutual funds			9,717				—				—				9,717
	Certificates of deposit and time deposits			—				1,627				—				1,627
	Non-U.S. government securities			—				84				—				84
	Total			644,226				362,082				—				1,006,308
	Derivatives			—				121				—				121
	Total		$	644,226			$	362,203			$	—			$	1,006,429
Liabilities
Contingent consideration		$	—			$	—			$	388			$	388
Total		$	—			$	—			$	388			$	388
Reported as follows:
		(Level 1)				(Level 2)				(Level 3)				Total
		(in thousands)
Assets
Cash and cash equivalents		$	322,393			$	16,527			$	—			$	338,920
Marketable securities			239,192				192,324				—				431,516
Long-term marketable securities			82,641				153,231				—				235,872
Other current assets			—				121				—				121
		$	644,226			$	362,203			$	—			$	1,006,429
Liabilities
Other accrued liabilities		$	—			$	—			$	388			$	388
		$	—			$	—			$	388			$	388
During the nine months ended September 29, 2013, Teradyne made the final payment for Level 3 contingent consideration of $0.4 million.
The carrying amounts and fair values of financial instruments at September 29, 2013 and December 31, 2012 were as follows:
		September 29, 2013								December 31, 2012
		Carrying Value				Fair Value				Carrying Value				Fair Value
		(in thousands)
Cash and cash equivalents		$	572,868			$	572,868			$	338,920			$	338,920
Marketable securities			586,421				586,421				667,388				667,388
Convertible debt(1)			181,550				580,206				169,896				589,000
Japan loan			2,023				2,023				3,491				3,491
-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 September 29, 2013 and December 31, 2012:
		September 29, 2013
		Available-for-Sale																Fair Market
																		Value of
																		Investments
																		with  Unrealized
		Cost				Unrealized				Unrealized				Fair Market				Losses
						Gain				(Loss)				Value
		(in thousands)
U.S. government agency securities		$	229,133			$	142			$	(146	)		$	229,129			$	103,165
U.S. Treasury securities			211,966				140				(150	)			211,956				5,605
Commercial paper			88,884				12				(5	)			88,891				25,169
Corporate debt securities			44,132				905				(1,055	)			43,982				16,439
Equity and debt mutual funds			9,843				2,315				(36	)			12,122				595
Certificates of deposit and time deposits			261				—				—				261				—
Non-U.S. government securities			80				—				—				80				—
		$	584,299			$	3,514			$	(1,392	)		$	586,421			$	150,973
Reported as follows:
		Cost				Unrealized				Unrealized				Fair Market				Fair Market
						Gain				(Loss)				Value				Value of
																		Investments
																		with Unrealized
																		Losses
		(in thousands)
Marketable securities		$	384,180			$	168			$	(14	)		$	384,334			$	37,823
Long-term marketable securities			200,119				3,346				(1,378	)			202,087				113,150
		$	584,299			$	3,514			$	(1,392	)		$	586,421			$	150,973
		December 31, 2012
		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		$	311,915			$	216			$	(15	)		$	312,116			$	1,018
U.S. government agency securities			217,396				262				(3	)			217,655				9,018
Commercial paper			70,431				9				(6	)			70,434				25,209
Corporate debt securities			53,405				2,414				(64	)			55,755				23,255
Equity and debt mutual funds			8,767				961				(11	)			9,717				600
Certificates of deposit and time deposits			1,627				—				—				1,627				—
Non-U.S. government securities			84				—				—				84				—
		$	663,625			$	3,862			$	(99	)		$	667,388			$	59,100
Reported as follows:
		Cost				Unrealized				Unrealized				Fair Market				Fair Market
						Gain				(Loss)				Value				Value of
																		Investments
																		with Unrealized
																		Losses
		(in thousands)
Marketable securities		$	431,324			$	203			$	(11	)		$	431,516			$	41,110
Long-term marketable securities			232,301				3,659				(88	)			235,872				17,990
		$	663,625			$	3,862			$	(99	)		$	667,388			$	59,100
As of September 29, 2013, the fair market value of marketable securities with unrealized losses totaled $151.0 million. Of this value, $0.5 million had unrealized losses greater than one year and $150.5 million had unrealized losses less than one year. As of December 31, 2012, the fair market value of marketable securities with unrealized losses totaled $59.1 million and none of the unrealized losses were greater than one year.
The contractual maturities of available-for-sale marketable securities at September 29, 2013 were as follows:
		September 29, 2013
		Cost				Fair Market
						Value
		(in thousands)
Due within one year		$	384,180			$	384,334
Due after 1 year through 5 years			173,407				175,657
Due after 5 years through 10 years			3,131				3,188
Due after 10 years			23,581				23,242
Total		$	584,299			$	586,421
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 net monetary assets. 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 fair value of the monetary assets and liabilities denominated in foreign currencies.
The notional amount of foreign exchange contracts hedging monetary assets and liabilities denominated in foreign currencies was $64.1 million and $64.1 million at September 29, 2013 and December 31, 2012, respectively.
The following table summarizes the fair value of derivative instruments at September 29, 2013 and December 31, 2012:
		Balance Sheet Location				September 29,				December 31,
						2013				2012
						(in thousands)
Derivatives not designated as hedging instruments:
Foreign exchange contracts			Other current assets			$	276			$	121
						$	276			$	121
Teradyne had no offsetting foreign exchange contracts at September 29, 2013 and December 31, 2012.
The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three and nine months ended September 29, 2013 and September 30, 2012. The table does not reflect the corresponding (losses) gains from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. For the three and nine months ended September 29, 2013, losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $(0.4) million and $(5.0) million, respectively. For the three and nine months ended September 30, 2012, gains from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $1.2 million and $0.8 million, respectively.
		Location of Gains		For the Three								For the Nine
		(Losses)		Months Ended								Months  Ended
		Recognized in
		Statement
		of Operations		September 29,				September 30,				September 29,				September 30,
				2013				2012				2013				2012
				(in thousands)
Derivatives not designated as hedging instruments:
Foreign exchange contracts		Interest expense		$	1			$	(1,197	)		$	4,068			$	(677	)
		and other
				$	1			$	(1,197	)		$	4,068			$	(677	)
See Note E “Debt” regarding derivatives related to convertible senior notes.

Debt

Debt	9 Months Ended
	Sep. 29, 2013
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 is denominated in Japanese Yen). The loan has a term of 5 years and a fixed interest rate of 0.8%. Approximately $6.0 million of the loan is collateralized by a real estate mortgage on Teradyne K.K.’s building and land in Kumamoto, Japan and approximately $4.0 million is unsecured. Teradyne, Inc. has guaranteed payment of the loan obligation. The loan is amortized over the term of the loan with semiannual principal payments of approximately $1.0 million payable on September 30 and March 30 each year. At September 29, 2013, the outstanding loan principal of approximately $2.0 million is included in current debt.
	Convertible Senior Notes
	In April 2009, Teradyne issued 4.50% convertible senior notes (the “Notes”) at an aggregate principal amount of $190 million. The Notes will mature on March 15, 2014, unless earlier repurchased by Teradyne or converted. The Notes are senior unsecured obligations and rank equally with all of Teradyne’s existing and future senior debt and senior to any of Teradyne’s subordinated debt.
	The Notes may be converted, at the option of the holder, under certain circumstances and during certain periods, at an initial conversion rate of approximately 182.65 shares of Teradyne’s common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $5.48, a 25% conversion premium based on the last reported sale price of $4.38 per share of Teradyne’s common stock on March 31, 2009. The conversion rate is subject to adjustment in certain circumstances including but not limited to Teradyne issuing a cash or stock dividend or effecting a stock split.
	During the three months ended September 29, 2013, the following circumstance occurred that allows holders to convert their Notes at their option prior to December 15, 2013: the last reported sale price of Teradyne’s common stock for 20 or more trading days in a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter exceeded 130% of the conversion price in effect on the last trading day of the immediately preceding calendar quarter. As of November 8, 2013, one holder exercised the option to convert two thousand dollars worth of Notes which Teradyne settled in cash.
	Concurrently with the offering of the Notes, Teradyne entered into a convertible note hedge transaction with a strike price equal to the initial conversion price of the Notes, or approximately $5.48. The convertible note hedge allows Teradyne to receive shares of its common stock and/or cash related to the excess conversion value that it would pay to the holders of the Notes upon conversion. The convertible note hedges will cover, subject to customary antidilution adjustments, approximately 34,703,196 shares of Teradyne’s common stock. Teradyne paid approximately $64.6 million for the convertible note hedges.
	On March 31, 2009, Teradyne entered into a warrant transaction with a strike price of approximately $7.67 per share, which was 75% higher than the closing price of Teradyne’s common stock. Teradyne received approximately $43.0 million for the warrants.
	The convertible note hedge and warrant transaction will generally have the effect of increasing the conversion price of the Notes to approximately $7.67 per share of Teradyne’s common stock, representing a 75% conversion premium based upon the closing price of Teradyne’s common stock on March 31, 2009.
	The Notes are classified as current debt in the balance sheet at September 29, 2013. The tables below represent the components of Teradyne’s convertible senior notes:
		September 29,		December 31,
		2013		2012
		(in thousands)
	Debt principal	$	189,998	$	190,000
	Unamortized debt discount		8,448		20,104
	Net carrying amount of the convertible debt	$	181,550	$	169,896
	The interest expense on Teradyne’s convertible senior notes for the three and nine months ended September 29, 2013 and September 30, 2012 was as follows:
		For the Three Months				For the Nine Months
		Ended				Ended
		September 29,		September 30,		September 29,		September 30,
		2013		2012		2013		2012
		(in thousands)
	Contractual interest expense	$	2,114	$	2,114	$	6,388	$	6,413
	Amortization of the discount component and debt issue fees		4,221		3,710		12,266		10,781
	Total interest expense on the convertible debt	$	6,335	$	5,824	$	18,654	$	17,194
	As of September 29, 2013, the unamortized discount was $8.4 million, which will be amortized over the next six months, and the carrying amount of the equity component was $63.4 million. As of September 29, 2013, the conversion rate was equal to the initial conversion price of approximately $5.48 per share and the if-converted value of the Notes was $579.9 million.

Deferred_Revenue_and_Customer_

Deferred Revenue and Customer Advances	9 Months Ended
	Sep. 29, 2013
Deferred Revenue and Customer Advances	'
	F. 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.
		September 29,		December 31,
		2013		2012
		(in thousands)
	Maintenance, training and extended warranty	$	56,481	$	51,198
	Customer advances		22,287		39,613
	Undelivered elements		9,054		6,773
	Total deferred revenue and customer advances	$	87,822	$	97,584

Product_Warranty

Product Warranty	9 Months Ended
	Sep. 29, 2013
Product Warranty	'
	G. 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.
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Balance at beginning of period	$	7,351		$	11,047		$	9,786		$	8,154
	Accruals for warranties issued during the period		3,674			4,118			8,781			13,543
	Adjustments related to pre-existing warranties		(524	)		1,226			(2,323	)		1,369
	Settlements made during the period		(2,470	)		(3,813	)		(8,213	)		(10,488	)
	Balance at end of period	$	8,031		$	12,578		$	8,031		$	12,578
	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.
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Balance at beginning of period	$	34,854		$	20,754		$	26,987		$	12,742
	Deferral of new extended warranty revenue		5,586			8,733			17,791			21,015
	Recognition of extended warranty deferred revenue		(4,120	)		(2,007	)		(8,458	)		(6,277	)
	Balance at end of period	$	36,320		$	27,480		$	36,320		$	27,480

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 29, 2013
Stock-Based Compensation	'
	H. Stock-Based Compensation
	Restricted stock unit awards granted to employees vest in equal installments over four years. A portion of restricted stock unit awards granted to executive officers is subject to time-based vesting and a portion is subject to performance-based vesting. The percentage level of performance satisfied for performance-based grants is assessed on or near the anniversary of the grant date and, in turn, that percentage level determines the number of performance-based restricted stock units available for vesting over the vesting period; portions of the performance-based grants not available for vesting will be forfeited. Stock options vest in equal installments over four years, and have a term of seven years from the date of grant.
	During the nine months ended September 29, 2013, Teradyne granted 1.9 million of restricted stock unit awards to employees at a weighted average grant date fair value of $16.60 and 0.2 million of service-based stock options to executive officers at a weighted average grant date fair value of $6.09.
	During the nine months ended September 30, 2012, Teradyne granted 1.7 million of restricted stock unit awards to employees at a weighted average grant date fair value of $16.73 and 0.2 million of service-based stock options to executive officers at a weighted average grant date fair value of $6.85.
	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:
		For the Nine Months
		Ended
		September 29,			September 30,
		2013			2012
	Expected life (years)		4			3.5
	Interest rate		0.6	%		0.4	%
	Volatility-historical		46.8	%		56	%
	Dividend yield		0	%		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 rate was determined using the U.S. Treasury yield curve in effect at the time of grant.
	Effective January 1, 2013, the price paid by employees for Teradyne’s common stock purchased through the employee stock purchase plan is equal to 85% of the stock price on the last business day of the purchase period.
	During 2012, the price paid by employees for Teradyne’s common stock purchased through the employee stock purchase plan was equal to 85% of the lower of the stock price on the first or last business day of the purchase period.
	The weighted-average fair value of employee stock purchase rights granted in the nine months ended September 30, 2012 was $3.75. The fair value of the employees’ purchase rights granted in the nine months ended September 30, 2012 was estimated using the Black-Scholes option-pricing model with the following assumptions:
		For the Nine Months Ended
		September 30,
		2012
	Expected life (years)		0.5
	Interest rate		0.11	%
	Volatility-historical		42.7	%
	Dividend yield		0	%

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 29, 2013
Accumulated Other Comprehensive Income	'
	I. 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, 2012 (a)		$	2,925		$	2,895		$	5,820
	Other comprehensive income before reclassifications			(1,019	)		—			(1,019	)
	Amounts reclassified from accumulated other comprehensive income			(621	)		(325	)		(946	)
	Net current period other comprehensive income			(1,640	)		(325	)		(1,965	)
	Balance at September 29, 2013 (a)		$	1,285		$	2,570		$	3,855
	(a)	Net of tax of $835 for unrealized gains on marketable securities and $(125) for retirement plans prior service credit.
	Reclassifications out of accumulated other comprehensive income to the statement of operations for the three and nine months ended September 29, 2013 and September 30, 2012, were as follows:
	Details about Accumulated		For the Three Months Ended						For the Nine Months Ended					Affected Line Item
	Other Comprehensive Income													in the  Statements
	Components													of Operations
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
						(in thousands)
	Available-for-sale marketable securities
	Unrealized gains		$	202		$	93		$	621		$	583	Interest income
			$	202		$	93		$	621		$	583
	Amortization of defined benefit pension and postretirement plans
	Prior service benefit		$	109		$	92		$	325		$	275	(a)
			$	109		$	92		$	325		$	275
	Total reclassifications		$	311		$	185		$	946		$	858	Net income
	(a)	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note M “Retirement Plans.”

Intangible_Assets

Intangible Assets	9 Months Ended
	Sep. 29, 2013
Intangible Assets	'
	J. Intangible Assets
	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet:
		September 29, 2013
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	358,555	$	180,960	$	177,595		6.3 years
	Customer relationships and service and software maintenance contracts		144,971		77,139		67,832		8.0 years
	Trade names and trademarks		33,840		13,562		20,278		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	538,366	$	272,661	$	265,705		7.0 years
		December 31, 2012
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	357,555	$	143,126	$	214,429		6.3 years
	Customer relationships and service and software maintenance contracts		144,971		63,464		81,507		8.0 years
	Trade names and trademarks		33,840		10,909		22,931		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	537,366	$	218,499	$	318,867		7.0 years
	Aggregate intangible asset amortization expense was $18.1 million and $54.2 million, respectively, for the three and nine months ended September 29, 2013 and $18.4 million and $55.3 million, respectively, for the three and nine months ended September 30, 2012. Estimated intangible asset amortization expense for each of the five succeeding fiscal years is as follows:
	Year	Amortization Expense
		(in thousands)
	2013 (remainder)	$	18,052
	2014		69,213
	2015		52,462
	2016		52,462
	2017		46,304

Net_Income_per_Common_Share

Net Income per Common Share	9 Months Ended
	Sep. 29, 2013
Net Income per Common Share	'
	K. Net Income per Common Share
	The following table sets forth the computation of basic and diluted net income per common share:
			For the Three Months				For the Nine Months
			Ended				Ended
			September 29,		September 30,		September 29,		September 30,
			2013		2012		2013		2012
			(in thousands, except per share amounts)
	Net income for basic and diluted net income per share		$	69,459	$	88,641	$	142,604	$	233,592
	Weighted average common shares-basic			191,307		187,364		190,521		186,592
	Effect of dilutive potential common shares:
	Incremental shares from assumed conversion of convertible notes(1)			23,257		21,890		23,303		22,397
	Convertible note hedge warrant shares(2)			18,678		16,765		18,742		17,474
	Restricted stock units			1,102		1,423		1,000		1,413
	Stock options			1,465		1,735		1,564		2,075
	Employee stock purchase rights			19		33		35		52
	Dilutive potential common shares			44,521		41,846		44,644		43,411
	Weighted average common shares-diluted			235,828		229,210		235,165		230,003
	Net income per common share-basic		$	0.36	$	0.47	$	0.75	$	1.25
	Net income per common share-diluted		$	0.29	$	0.39	$	0.61	$	1.02
	-1	Incremental shares from assumed conversion of the convertible notes for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by the 34.7 million shares that would be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, is divided by the average Teradyne stock price for the period.
	-2	Convertible note hedge warrant shares for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.67, multiplied by the 34.7 million shares that would be issued upon conversion. 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 and nine months ended September 29, 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.
	The computation of diluted net income per common share for the three and nine months ended September 30, 2012 excludes the effect of the potential exercise of stock options to purchase approximately 0.3 million shares, and the computation of the three and nine months ended September 30, 2012 excludes the effect of the potential exercise of restricted stock units of 0.1 million and 0.4 million, because the effect would have been anti-dilutive.
	With respect to Teradyne’s convertible debt, Teradyne intends to settle its conversion spread (i.e., the intrinsic value of the embedded option feature contained in the convertible debt) in shares. Teradyne accounts for its conversion spread using the treasury stock method.

Restructuring_and_Other

Restructuring and Other	9 Months Ended
	Sep. 29, 2013
Restructuring and Other	'
	L. Restructuring and Other
	Restructuring
	During the nine months ended September 29, 2013, Teradyne recorded $1.3 million of severance charges related to headcount reductions of 40 people, of which $1.0 million was in System Test and $0.3 million was in Semiconductor Test, and a $(0.4) million credit in Corporate for a change in the estimated exit costs related to a leased facility.
	During the nine months ended September 30, 2012, Teradyne recorded $0.7 million of severance charges related to headcount reductions of 9 people, of which $0.5 million and 7 people were in System Test, $0.2 million and 2 people were in Wireless Test.
		Severance			Facility			Total
		and			Exit
		Benefits			Costs
		(in thousands)
	Pre-2012 Activities
	Balance at December 31, 2011	$	325		$	1,862		$	2,187
	Cash payments		(325	)		(778	)		(1,103	)
	Balance at December 31, 2012		—			1,084			1,084
	Change in estimate		—			(105	)		(105	)
	Cash payments		—			(183	)		(183	)
	Balance at March 31, 2013		—			796			796
	Cash payments		—			(199	)		(199	)
	Balance at June 30, 2013		—			597			597
	Change in estimate		—			(448	)		(448	)
	Cash payments		—			(149	)		(149	)
	Balance at September 29, 2013	$	—		$	—		$	—
	2012 Activities
	Q3 2012 Activity:
	Provision	$	687		$	—		$	687
	Cash payments		(444	)		—			(444	)
	Balance at December 31, 2012		243			—			243
	Cash payments		(243	)		—			(243	)
	Balance at March 31, 2013	$	—		$	—		$	—
	2013 Activities
	Q3 2013 Activity:
	Provision	$	1,337		$	—		$	1,337
	Cash payments		(884	)		—			(884	)
	Balance at September 29, 2013	$	453		$	—		$	453
	Balance at September 29, 2013	$	453		$	—		$	453
	The remaining accrual for severance and benefits of $0.5 million is reflected in the accrued employees’ compensation and withholdings on the balance sheet and is expected to be paid by June 2014.
	Other
	During the nine months ended September 30, 2012, due to a decrease in specified new product revenue through December 31, 2012 earn-out period end date, Teradyne recorded an $8.4 million fair value adjustment to decrease the LitePoint acquisition contingent consideration.

Retirement_Plans

Retirement Plans	9 Months Ended
	Sep. 29, 2013
Retirement Plans	'
	M. Retirement Plans
	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.
	Net periodic pension cost was comprised of the following:
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Service cost	$	871		$	685		$	2,557		$	2,054
	Interest cost		3,350			4,111			10,001			12,333
	Expected return on plan assets		(3,664	)		(4,090	)		(10,925	)		(12,269	)
	Amortization of unrecognized prior service cost		41			58			123			174
	Actuarial loss (gain)		—			1,937			(1,122	)		5,083
	Total net periodic pension cost	$	598		$	2,701		$	634		$	7,375
	In the nine months ended September 29, 2013, Teradyne contributed $1.3 million to the U.S. supplemental executive defined benefit pension plan and $1.3 million to certain qualified plans for non-U.S. subsidiaries.
	During the three months ended September 30, 2012, Teradyne offered to certain former U.S. employees the option to receive their vested pension benefit as a one-time lump sum payment. Approximately 2,000 former employees selected to receive a one-time lump sum payment. Total one-time lump sum payments were approximately $52.0 million.
	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.
	Net periodic postretirement benefit was comprised of the following:
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Service cost	$	19		$	17		$	56		$	50
	Interest cost		86			109			257			328
	Amortization of unrecognized prior service benefit		(150	)		(150	)		(449	)		(449	)
	Actuarial gain		—			—			(236	)		(92	)
	Total net periodic post-retirement benefit	$	(45	)	$	(24	)	$	(372	)	$	(163	)

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 29, 2013
Commitments and Contingencies	'
	N. Commitments and Contingencies
	Purchase Commitments
	As of September 29, 2013, Teradyne had entered into purchase commitments for certain components and materials. The purchase commitments aggregate to approximately $243.3 million, of which $231.5 million is for less than one year.
	Legal Claims
	Teradyne is subject to various legal proceedings and claims which have arisen in the ordinary course of business. In the opinion of management, other than set forth herein, the ultimate disposition of these matters will not have a material adverse effect on Teradyne’s results of operations, financial condition or cash flows.
	On May 17, 2013, Boston Semi Equipment (“BSE”) filed a complaint against Teradyne for antitrust violations and unfair business practices alleging that Teradyne excluded BSE from competing in the market for the sale of reconfigured Teradyne equipment and the market for the repair of Teradyne equipment. BSE sought unspecified damages and an injunction. Teradyne filed a motion to dismiss the complaint. On October 18, 2013, the parties settled the litigation. The settlement included no monetary consideration. The settlement did not and will not have a material impact on Teradyne’s consolidated financial results.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 29, 2013
Income Taxes	'
	O. Income Taxes
	The effective tax rate for the three months ended September 29, 2013 and September 30, 2012 was 21% and 14%, respectively. The increase in Teradyne’s tax rate for the three months ended September 29, 2013 compared to the three months ended September 30, 2012, was primarily attributable to the reduction to deferred income tax benefit recognized discretely in 2012 in connection with Teradyne’s plan to repatriate the unremitted earnings of its Japanese subsidiary.
	The effective tax rate for the nine months ended September 29, 2013 and September 30, 2012 was 14% and 21%, respectively. The decrease in Teradyne’s tax rate for the nine months ended September 29, 2013 compared to the nine months ended September 30, 2012, was primarily the result of recognizing the tax benefit attributable to the retroactive reinstatement of the U.S. research and development credit and the mix of income by jurisdiction.
	The effective tax rate for the three months and nine months ended September 29, 2013 is lower than the 35% U.S. statutory federal tax rate primarily due to the research and development credit and the effect of foreign income taxed at a rate lower than the U.S. statutory rate.

Segment_Information

Segment Information	9 Months Ended
	Sep. 29, 2013
Segment Information	'
	P. 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, 2012. Segment information is as follows:
			Semiconductor			Wireless			System			Corporate			Consolidated
			Test			Test			Test			and
												Eliminations
			(in thousands)
	Three months ended September 29, 2013:
	Net revenues		$	304,131		$	93,132		$	36,113		$	—		$	433,376
	Income (loss) before income taxes(1)(2)			68,932			27,575			(2,462	)		(6,493	)		87,552
	Three months ended September 30, 2012:
	Net revenues		$	310,979		$	118,571		$	33,844		$	—		$	463,394
	Income (loss) before income taxes(1)(2)			55,348			58,902			(2,642	)		(8,583	)		103,025
	Nine months ended September 29, 2013:
	Net revenues		$	808,068		$	226,116		$	108,448		$	—		$	1,142,632
	Income (loss) before income taxes(1)(2)			141,304			41,491			(153	)		(16,159	)		166,483
	Nine months ended September 30, 2012:
	Net revenues		$	943,625		$	261,827		$	202,894		$	—		$	1,408,346
	Income (loss) before income taxes(1)(2)			181,594			97,729			30,964			(14,026	)		296,261
	-1	Pension and post retirement actuarial gains and losses, 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 and nine months ended September 29, 2013 and September 30, 2012 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						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	1,378		$	3,085		$	1,878		$	9,254
	Restructuring and other			282			(4	)		416			315
	Total		$	1,660		$	3,081		$	2,294		$	9,569
	Included in the Wireless Test segment are charges for the following:
			For the Three Months						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	2,059		$	2,018		$	6,125		$	4,134
	Cost of revenues—inventory step-up			—			—			—			6,089
	Restructuring and other			—			236			82			236
	Total		$	2,059		$	2,254		$	6,207		$	10,459
	Included in the System Test segment are charges for the following:
			For the Three Months						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	404		$	378		$	1,613		$	3,020
	Restructuring and other			1,055			451			1,430			451
	Total		$	1,459		$	829		$	3,043		$	3,471
	Included in Corporate and Eliminations are credits for the following:
			For the Three Months						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Restructuring and other		$	(448	)	$	—		$	(448	)	$	(8,406	)
	Total		$	(448	)	$	—		$	(448	)	$	(8,406	)

Stock_Repurchase_Program

Stock Repurchase Program	9 Months Ended
	Sep. 29, 2013
Stock Repurchase Program	'
	Q. Stock Repurchase Program
	In November 2010, Teradyne’s board of directors authorized a stock repurchase program for up to $200 million. In the three and nine months ended September 29, 2013 and September 30, 2012, Teradyne did not repurchase any shares. Cumulatively, as of September 29, 2013, Teradyne has repurchased 2.6 million shares of common stock for $31.2 million at an average price of $11.84.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 29, 2013
Subsequent Events	'
	R. Subsequent Events
	On October 25, 2013, Teradyne completed its acquisition of ZTEC Instruments, Inc. (“ZTEC”) located in Albuquerque, New Mexico. The acquisition was completed by acquiring all of the common and preferred stock of ZTEC for approximately $15 million and up to $5 million payable upon achievement of certain performance targets through December 31, 2015. The fair value of assets and liabilities acquired has not been disclosed because Teradyne has not completed the valuation. ZTEC is a supplier of modular wireless test instruments. The acquisition of ZTEC expands Teradyne’s wireless segment into the design verification test of wireless components and chipsets.
	On November 1, 2013, Teradyne sold its equity interest in Empirix Inc. and received proceeds of $34.2 million. An additional $5.2 million of proceeds will be held in escrow for 15 months, for potential indemnifications to the buyer. Teradyne will record a gain of $34.2 million in the fourth quarter of 2013.

Accounting_Policies_Policies

Accounting Policies (Policies)	9 Months Ended
	Sep. 29, 2013
Basis of Presentation	'
	Basis of Presentation
	The condensed 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, 2012 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. Security and Exchange Commission (“SEC”) on March 1, 2013, for the year ended December 31, 2012.
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)	9 Months Ended
	Sep. 29, 2013
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 September 29, 2013 and December 31, 2012.
			September 29, 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		$	147,819			$	—			$	—			$	147,819
	Cash equivalents			417,823				7,226				—				425,049
	Available-for-sale securities:
	U.S. government agency securities			—				229,129				—				229,129
	U.S. Treasury securities			211,956				—				—				211,956
	Commercial paper			—				88,891				—				88,891
	Corporate debt securities			—				43,982				—				43,982
	Equity and debt mutual funds			12,122				—				—				12,122
	Certificates of deposit and time deposits			—				261				—				261
	Non-U.S. government securities			—				80				—				80
	Total			789,720				369,569				—				1,159,289
	Derivatives			—				276				—				276
	Total		$	789,720			$	369,845			$	—			$	1,159,565
	Reported as follows:
			(Level 1)				(Level 2)				(Level 3)				Total
			(in thousands)
	Assets
	Cash and cash equivalents		$	565,642			$	7,226			$	—			$	572,868
	Marketable securities			185,085				199,249				—				384,334
	Long-term marketable securities			38,993				163,094				—				202,087
	Other current assets			—				276				—				276
			$	789,720			$	369,845			$	—			$	1,159,565
			December 31, 2012
			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		$	139,354			$	—			$	—			$	139,354
	Cash equivalents			183,039				16,527				—				199,566
	Available-for-sale securities:
	U.S. Treasury securities			312,116				—				—				312,116
	U.S. government agency securities			—				217,655				—				217,655
	Commercial paper			—				70,434				—				70,434
	Corporate debt securities			—				55,755				—				55,755
	Equity and debt mutual funds			9,717				—				—				9,717
	Certificates of deposit and time deposits			—				1,627				—				1,627
	Non-U.S. government securities			—				84				—				84
	Total			644,226				362,082				—				1,006,308
	Derivatives			—				121				—				121
	Total		$	644,226			$	362,203			$	—			$	1,006,429
	Liabilities
	Contingent consideration		$	—			$	—			$	388			$	388
	Total		$	—			$	—			$	388			$	388
	Reported as follows:
			(Level 1)				(Level 2)				(Level 3)				Total
			(in thousands)
	Assets
	Cash and cash equivalents		$	322,393			$	16,527			$	—			$	338,920
	Marketable securities			239,192				192,324				—				431,516
Long-term marketable securities			82,641				153,231				—				235,872
Other current assets			—				121				—				121
		$	644,226			$	362,203			$	—			$	1,006,429
Liabilities
Other accrued liabilities		$	—			$	—			$	388			$	388
		$	—			$	—			$	388			$	388
Schedule of Carrying Amounts and Fair Values of Financial Instruments	'
	The carrying amounts and fair values of financial instruments at September 29, 2013 and December 31, 2012 were as follows:
			September 29, 2013								December 31, 2012
			Carrying Value				Fair Value				Carrying Value				Fair Value
			(in thousands)
	Cash and cash equivalents		$	572,868			$	572,868			$	338,920			$	338,920
	Marketable securities			586,421				586,421				667,388				667,388
	Convertible debt(1)			181,550				580,206				169,896				589,000
	Japan loan			2,023				2,023				3,491				3,491
	-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 September 29, 2013 and December 31, 2012:
			September 29, 2013
			Available-for-Sale																Fair Market
																			Value of
																			Investments
																			with  Unrealized
			Cost				Unrealized				Unrealized				Fair Market				Losses
							Gain				(Loss)				Value
			(in thousands)
	U.S. government agency securities		$	229,133			$	142			$	(146	)		$	229,129			$	103,165
	U.S. Treasury securities			211,966				140				(150	)			211,956				5,605
	Commercial paper			88,884				12				(5	)			88,891				25,169
	Corporate debt securities			44,132				905				(1,055	)			43,982				16,439
	Equity and debt mutual funds			9,843				2,315				(36	)			12,122				595
	Certificates of deposit and time deposits			261				—				—				261				—
	Non-U.S. government securities			80				—				—				80				—
			$	584,299			$	3,514			$	(1,392	)		$	586,421			$	150,973
	Reported as follows:
			Cost				Unrealized				Unrealized				Fair Market				Fair Market
							Gain				(Loss)				Value				Value of
																			Investments
																			with Unrealized
																			Losses
			(in thousands)
	Marketable securities		$	384,180			$	168			$	(14	)		$	384,334			$	37,823
	Long-term marketable securities			200,119				3,346				(1,378	)			202,087				113,150
			$	584,299			$	3,514			$	(1,392	)		$	586,421			$	150,973
			December 31, 2012
			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		$	311,915			$	216			$	(15	)		$	312,116			$	1,018
	U.S. government agency securities			217,396				262				(3	)			217,655				9,018
	Commercial paper			70,431				9				(6	)			70,434				25,209
	Corporate debt securities			53,405				2,414				(64	)			55,755				23,255
	Equity and debt mutual funds			8,767				961				(11	)			9,717				600
	Certificates of deposit and time deposits			1,627				—				—				1,627				—
	Non-U.S. government securities			84				—				—				84				—
			$	663,625			$	3,862			$	(99	)		$	667,388			$	59,100
	Reported as follows:
			Cost				Unrealized				Unrealized				Fair Market				Fair Market
							Gain				(Loss)				Value				Value of
																			Investments
																			with Unrealized
																			Losses
			(in thousands)
	Marketable securities		$	431,324			$	203			$	(11	)		$	431,516			$	41,110
	Long-term marketable securities			232,301				3,659				(88	)			235,872				17,990
			$	663,625			$	3,862			$	(99	)		$	667,388			$	59,100
Contractual Maturities of Available-for-Sale Marketable Securities	'
	The contractual maturities of available-for-sale marketable securities at September 29, 2013 were as follows:
			September 29, 2013
			Cost				Fair Market
							Value
			(in thousands)
	Due within one year		$	384,180			$	384,334
	Due after 1 year through 5 years			173,407				175,657
	Due after 5 years through 10 years			3,131				3,188
	Due after 10 years			23,581				23,242
	Total		$	584,299			$	586,421
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	'
	The following table summarizes the fair value of derivative instruments at September 29, 2013 and December 31, 2012:
			Balance Sheet Location				September 29,				December 31,
							2013				2012
							(in thousands)
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts			Other current assets			$	276			$	121
							$	276			$	121
Schedule of Effect of Derivative Instruments on Statement of Operations Recognized	'
	The following table summarizes the effect of derivative instruments recognized in the statement of operations during the three and nine months ended September 29, 2013 and September 30, 2012. The table does not reflect the corresponding (losses) gains from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. For the three and nine months ended September 29, 2013, losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $(0.4) million and $(5.0) million, respectively. For the three and nine months ended September 30, 2012, gains from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $1.2 million and $0.8 million, respectively.
			Location of Gains		For the Three								For the Nine
			(Losses)		Months Ended								Months  Ended
			Recognized in
			Statement
			of Operations		September 29,				September 30,				September 29,				September 30,
					2013				2012				2013				2012
					(in thousands)
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts		Interest expense		$	1			$	(1,197	)		$	4,068			$	(677	)
			and other
					$	1			$	(1,197	)		$	4,068			$	(677	)

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 29, 2013
Components of Convertible Senior Notes	'
	The tables below represent the components of Teradyne’s convertible senior notes:
		September 29,		December 31,
		2013		2012
		(in thousands)
	Debt principal	$	189,998	$	190,000
	Unamortized debt discount		8,448		20,104
	Net carrying amount of the convertible debt	$	181,550	$	169,896
Interest Expense on Convertible Senior Notes	'
	The interest expense on Teradyne’s convertible senior notes for the three and nine months ended September 29, 2013 and September 30, 2012 was as follows:
		For the Three Months				For the Nine Months
		Ended				Ended
		September 29,		September 30,		September 29,		September 30,
		2013		2012		2013		2012
		(in thousands)
	Contractual interest expense	$	2,114	$	2,114	$	6,388	$	6,413
	Amortization of the discount component and debt issue fees		4,221		3,710		12,266		10,781
	Total interest expense on the convertible debt	$	6,335	$	5,824	$	18,654	$	17,194

Deferred_Revenue_and_Customer_1

Deferred Revenue and Customer Advances (Tables)	9 Months Ended
	Sep. 29, 2013
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.
		September 29,		December 31,
		2013		2012
		(in thousands)
	Maintenance, training and extended warranty	$	56,481	$	51,198
	Customer advances		22,287		39,613
	Undelivered elements		9,054		6,773
	Total deferred revenue and customer advances	$	87,822	$	97,584

Product_Warranty_Tables

Product Warranty (Tables)	9 Months Ended
	Sep. 29, 2013
Other Accrued Liabilities	'
	The warranty balance below is included in other accrued liabilities.
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Balance at beginning of period	$	7,351		$	11,047		$	9,786		$	8,154
	Accruals for warranties issued during the period		3,674			4,118			8,781			13,543
	Adjustments related to pre-existing warranties		(524	)		1,226			(2,323	)		1,369
	Settlements made during the period		(2,470	)		(3,813	)		(8,213	)		(10,488	)
	Balance at end of period	$	8,031		$	12,578		$	8,031		$	12,578
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.
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Balance at beginning of period	$	34,854		$	20,754		$	26,987		$	12,742
	Deferral of new extended warranty revenue		5,586			8,733			17,791			21,015
	Recognition of extended warranty deferred revenue		(4,120	)		(2,007	)		(8,458	)		(6,277	)
	Balance at end of period	$	36,320		$	27,480		$	36,320		$	27,480

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 29, 2013
Stock Option	'
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 Nine Months
		Ended
		September 29,			September 30,
		2013			2012
	Expected life (years)		4			3.5
	Interest rate		0.6	%		0.4	%
	Volatility-historical		46.8	%		56	%
	Dividend yield		0	%		0	%
Stock Purchase Rights	'
Schedule of Estimated Fair Value of Stock Options Assumptions	'
	The fair value of the employees’ purchase rights granted in the nine months ended September 30, 2012 was estimated using the Black-Scholes option-pricing model with the following assumptions:
		For the Nine Months Ended
		September 30,
		2012
	Expected life (years)		0.5
	Interest rate		0.11	%
	Volatility-historical		42.7	%
	Dividend yield		0	%

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 29, 2013
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, 2012 (a)		$	2,925		$	2,895		$	5,820
	Other comprehensive income before reclassifications			(1,019	)		—			(1,019	)
	Amounts reclassified from accumulated other comprehensive income			(621	)		(325	)		(946	)
	Net current period other comprehensive income			(1,640	)		(325	)		(1,965	)
	Balance at September 29, 2013 (a)		$	1,285		$	2,570		$	3,855
	(a)	Net of tax of $835 for unrealized gains on marketable securities and $(125) for retirement plans prior service credit.
Reclassifications out of Accumulated Other Comprehensive Income	'
	Reclassifications out of accumulated other comprehensive income to the statement of operations for the three and nine months ended September 29, 2013 and September 30, 2012, were as follows:
	Details about Accumulated		For the Three Months Ended						For the Nine Months Ended					Affected Line Item
	Other Comprehensive Income													in the  Statements
	Components													of Operations
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
						(in thousands)
	Available-for-sale marketable securities
	Unrealized gains		$	202		$	93		$	621		$	583	Interest income
			$	202		$	93		$	621		$	583
	Amortization of defined benefit pension and postretirement plans
	Prior service benefit		$	109		$	92		$	325		$	275	(a)
			$	109		$	92		$	325		$	275
	Total reclassifications		$	311		$	185		$	946		$	858	Net income
	(a)	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note M “Retirement Plans.”

Intangible_Assets_Tables

Intangible Assets (Tables)	9 Months Ended
	Sep. 29, 2013
Schedule of Amortizable Intangible Assets	'
	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheet:
		September 29, 2013
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	358,555	$	180,960	$	177,595		6.3 years
	Customer relationships and service and software maintenance contracts		144,971		77,139		67,832		8.0 years
	Trade names and trademarks		33,840		13,562		20,278		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	538,366	$	272,661	$	265,705		7.0 years
		December 31, 2012
		Gross		Accumulated		Net		Weighted
		Carrying		Amortization		Carrying		Average
		Amount				Amount		Useful Life
		(in thousands)
	Developed technology	$	357,555	$	143,126	$	214,429		6.3 years
	Customer relationships and service and software maintenance contracts		144,971		63,464		81,507		8.0 years
	Trade names and trademarks		33,840		10,909		22,931		9.0 years
	Customer backlog		1,000		1,000		—		0.4 years
	Total intangible assets	$	537,366	$	218,499	$	318,867		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)
	2013 (remainder)	$	18,052
	2014		69,213
	2015		52,462
	2016		52,462
	2017		46,304

Net_Income_per_Common_Share_Ta

Net Income per Common Share (Tables)	9 Months Ended
	Sep. 29, 2013
Schedule of Computation of Basic and Diluted Net Income Per Common Share	'
	The following table sets forth the computation of basic and diluted net income per common share:
			For the Three Months				For the Nine Months
			Ended				Ended
			September 29,		September 30,		September 29,		September 30,
			2013		2012		2013		2012
			(in thousands, except per share amounts)
	Net income for basic and diluted net income per share		$	69,459	$	88,641	$	142,604	$	233,592
	Weighted average common shares-basic			191,307		187,364		190,521		186,592
	Effect of dilutive potential common shares:
	Incremental shares from assumed conversion of convertible notes(1)			23,257		21,890		23,303		22,397
	Convertible note hedge warrant shares(2)			18,678		16,765		18,742		17,474
	Restricted stock units			1,102		1,423		1,000		1,413
	Stock options			1,465		1,735		1,564		2,075
	Employee stock purchase rights			19		33		35		52
	Dilutive potential common shares			44,521		41,846		44,644		43,411
	Weighted average common shares-diluted			235,828		229,210		235,165		230,003
	Net income per common share-basic		$	0.36	$	0.47	$	0.75	$	1.25
	Net income per common share-diluted		$	0.29	$	0.39	$	0.61	$	1.02
	-1	Incremental shares from assumed conversion of the convertible notes for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by the 34.7 million shares that would be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, is divided by the average Teradyne stock price for the period.
	-2	Convertible note hedge warrant shares for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.67, multiplied by the 34.7 million shares that would be issued upon conversion. 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)	9 Months Ended
	Sep. 29, 2013
Restructuring and Other	'
		Severance			Facility			Total
		and			Exit
		Benefits			Costs
		(in thousands)
	Pre-2012 Activities
	Balance at December 31, 2011	$	325		$	1,862		$	2,187
	Cash payments		(325	)		(778	)		(1,103	)
	Balance at December 31, 2012		—			1,084			1,084
	Change in estimate		—			(105	)		(105	)
	Cash payments		—			(183	)		(183	)
	Balance at March 31, 2013		—			796			796
	Cash payments		—			(199	)		(199	)
	Balance at June 30, 2013		—			597			597
	Change in estimate		—			(448	)		(448	)
	Cash payments		—			(149	)		(149	)
	Balance at September 29, 2013	$	—		$	—		$	—
	2012 Activities
	Q3 2012 Activity:
	Provision	$	687		$	—		$	687
	Cash payments		(444	)		—			(444	)
	Balance at December 31, 2012		243			—			243
	Cash payments		(243	)		—			(243	)
	Balance at March 31, 2013	$	—		$	—		$	—
	2013 Activities
	Q3 2013 Activity:
	Provision	$	1,337		$	—		$	1,337
	Cash payments		(884	)		—			(884	)
	Balance at September 29, 2013	$	453		$	—		$	453
	Balance at September 29, 2013	$	453		$	—		$	453

Retirement_Plans_Tables

Retirement Plans (Tables)	9 Months Ended
	Sep. 29, 2013
Defined Benefit Pension Plans	'
Net Periodic Pension (Benefit) Cost	'
	Net periodic pension cost was comprised of the following:
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Service cost	$	871		$	685		$	2,557		$	2,054
	Interest cost		3,350			4,111			10,001			12,333
	Expected return on plan assets		(3,664	)		(4,090	)		(10,925	)		(12,269	)
	Amortization of unrecognized prior service cost		41			58			123			174
	Actuarial loss (gain)		—			1,937			(1,122	)		5,083
	Total net periodic pension cost	$	598		$	2,701		$	634		$	7,375
Post-Retirement Benefit Plans	'
Net Periodic Pension (Benefit) Cost	'
	Net periodic postretirement benefit was comprised of the following:
		For the Three Months						For the Nine Months
		Ended						Ended
		September 29,			September 30,			September 29,			September 30,
		2013			2012			2013			2012
		(in thousands)
	Service cost	$	19		$	17		$	56		$	50
	Interest cost		86			109			257			328
	Amortization of unrecognized prior service benefit		(150	)		(150	)		(449	)		(449	)
	Actuarial gain		—			—			(236	)		(92	)
	Total net periodic post-retirement benefit	$	(45	)	$	(24	)	$	(372	)	$	(163	)

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 29, 2013
Segment Information	'
	Segment information is as follows:
			Semiconductor			Wireless			System			Corporate			Consolidated
			Test			Test			Test			and
												Eliminations
			(in thousands)
	Three months ended September 29, 2013:
	Net revenues		$	304,131		$	93,132		$	36,113		$	—		$	433,376
	Income (loss) before income taxes(1)(2)			68,932			27,575			(2,462	)		(6,493	)		87,552
	Three months ended September 30, 2012:
	Net revenues		$	310,979		$	118,571		$	33,844		$	—		$	463,394
	Income (loss) before income taxes(1)(2)			55,348			58,902			(2,642	)		(8,583	)		103,025
	Nine months ended September 29, 2013:
	Net revenues		$	808,068		$	226,116		$	108,448		$	—		$	1,142,632
	Income (loss) before income taxes(1)(2)			141,304			41,491			(153	)		(16,159	)		166,483
	Nine months ended September 30, 2012:
	Net revenues		$	943,625		$	261,827		$	202,894		$	—		$	1,408,346
	Income (loss) before income taxes(1)(2)			181,594			97,729			30,964			(14,026	)		296,261
	-1	Pension and post retirement actuarial gains and losses, 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 and nine months ended September 29, 2013 and September 30, 2012 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						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	1,378		$	3,085		$	1,878		$	9,254
	Restructuring and other			282			(4	)		416			315
	Total		$	1,660		$	3,081		$	2,294		$	9,569
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						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	2,059		$	2,018		$	6,125		$	4,134
	Cost of revenues—inventory step-up			—			—			—			6,089
	Restructuring and other			—			236			82			236
	Total		$	2,059		$	2,254		$	6,207		$	10,459
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						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Cost of revenues—provision for excess and obsolete inventory		$	404		$	378		$	1,613		$	3,020
	Restructuring and other			1,055			451			1,430			451
	Total		$	1,459		$	829		$	3,043		$	3,471
Corporate And Eliminations	'
Schedule of Segment Reporting Information by Segment Charges	'
	Included in Corporate and Eliminations are credits for the following:
			For the Three Months						For the Nine Months
			Ended						Ended
			September 29,			September 30,			September 29,			September 30,
			2013			2012			2013			2012
			(in thousands)
	Restructuring and other		$	(448	)	$	—		$	(448	)	$	(8,406	)
	Total		$	(448	)	$	—		$	(448	)	$	(8,406	)

Financial_Instruments_and_Deri2

Financial Instruments and Derivatives - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012	Dec. 31, 2012
Financial Instruments and Fair Value [Line Items]	'	'	'	'	'
Available-for-sale securities, realized gain	$200,000	$300,000	$500,000	$900,000	'
Final payment for Level 3 contingent consideration	'	'	400,000	'	'
Fair market value of investments with unrealized losses	150,973,000	'	150,973,000	'	59,100,000
Available-for-sale marketable securities, fair market value of investments with unrealized losses greater than one year	500,000	'	500,000	'	'
Available-for-sale marketable securities, fair market value of investments with unrealized losses less than one year	150,500,000	'	150,500,000	'	'
Gain (loss) on foreign currency transactions	-400,000	1,200,000	-5,000,000	800,000	'
Foreign Exchange Contract	'	'	'	'	'
Financial Instruments and Fair Value [Line Items]	'	'	'	'	'
Notional amount of foreign exchange contracts hedging monetary assets and liabilities	$64,100,000	'	$64,100,000	'	$64,100,000

Schedule_of_Fair_Value_of_Fina

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	$586,421	$667,388
Derivatives	276	121
Total including derivatives	1,159,565	1,006,429
Contingent consideration	'	388
Liabilities	'	388
Cash	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	147,819	139,354
Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	425,049	199,566
U.S. Treasury Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	211,956	312,116
U.S. Government Agency Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	229,129	217,655
Commercial Paper	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	88,891	70,434
Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	43,982	55,755
Equity And Debt Mutual Funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	12,122	9,717
Certificates Of Deposit And Time Deposits	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	261	1,627
Non-U.S. Government Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	80	84
Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	1,159,289	1,006,308
Quoted Prices in Active Markets for Identical Instruments (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Total including derivatives	789,720	644,226
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	147,819	139,354
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	417,823	183,039
Quoted Prices in Active Markets for Identical Instruments (Level 1) | U.S. Treasury Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	211,956	312,116
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Equity And Debt Mutual Funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	12,122	9,717
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	789,720	644,226
Significant Other Observable Inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Derivatives	276	121
Total including derivatives	369,845	362,203
Significant Other Observable Inputs (Level 2) | Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Cash and Cash equivalents	7,226	16,527
Significant Other Observable Inputs (Level 2) | U.S. Government Agency Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	229,129	217,655
Significant Other Observable Inputs (Level 2) | Commercial Paper	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	88,891	70,434
Significant Other Observable Inputs (Level 2) | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	43,982	55,755
Significant Other Observable Inputs (Level 2) | Certificates Of Deposit And Time Deposits	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	261	1,627
Significant Other Observable Inputs (Level 2) | Non-U.S. Government Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	80	84
Significant Other Observable Inputs (Level 2) | Subtotal	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Available for sale securities	369,569	362,082
Significant Unobservable Inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Contingent consideration	'	388
Liabilities	'	$388

Schedule_of_Reported_Financial

Schedule of Reported Financial Assets and Liabilities (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	$1,159,565	$1,006,429
Liabilities	'	388
Cash and Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	572,868	338,920
Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	384,334	431,516
Long-term marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	202,087	235,872
Other current assets	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	276	121
Other Accrued Liabilities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	'	388
Quoted Prices in Active Markets for Identical Instruments (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	789,720	644,226
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	565,642	322,393
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	185,085	239,192
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	38,993	82,641
Significant Other Observable Inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	369,845	362,203
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	7,226	16,527
Significant Other Observable Inputs (Level 2) | Marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	199,249	192,324
Significant Other Observable Inputs (Level 2) | Long-term marketable securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	163,094	153,231
Significant Other Observable Inputs (Level 2) | Other current assets	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Assets	276	121
Significant Unobservable Inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	'	388
Significant Unobservable Inputs (Level 3) | Other Accrued Liabilities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	'	'
Liabilities	'	$388

Schedule_of_Carrying_Amounts_a

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) (USD $)	Sep. 29, 2013		Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011	Mar. 31, 2009
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'		'		'	'	'
Cash and cash equivalents, Carrying Value	$572,868		$338,920		$485,692	$573,736	'
Convertible debt, Carrying Value	181,550		169,896		'	'	'
Japan loan, Carrying Value	'		'		'	'	10,000
Carrying Value	'		'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'		'		'	'	'
Cash and cash equivalents, Carrying Value	572,868		338,920		'	'	'
Marketable securities, Carrying Value	586,421		667,388		'	'	'
Convertible debt, Carrying Value	181,550	[1]	169,896	[1]	'	'	'
Japan loan, Carrying Value	2,023		3,491		'	'	'
Fair Value	'		'		'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions	'		'		'	'	'
Cash and cash equivalents, Fair Value	572,868		338,920		'	'	'
Marketable securities, Fair Value	586,421		667,388		'	'	'
Convertible debt, Fair Value	580,206	[1]	589,000	[1]	'	'	'
Japan loan, Fair Value	$2,023		$3,491		'	'	'
[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 $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	$584,299	$663,625
Available-for-sale marketable securities, Unrealized Gain	3,514	3,862
Available-for-sale marketable securities, Unrealized (Loss)	-1,392	-99
Available-for-sale marketable securities, Fair Market Value	586,421	667,388
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	150,973	59,100
U.S. Government Agency Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	229,133	217,396
Available-for-sale marketable securities, Unrealized Gain	142	262
Available-for-sale marketable securities, Unrealized (Loss)	-146	-3
Available-for-sale marketable securities, Fair Market Value	229,129	217,655
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	103,165	9,018
U.S. Treasury Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	211,966	311,915
Available-for-sale marketable securities, Unrealized Gain	140	216
Available-for-sale marketable securities, Unrealized (Loss)	-150	-15
Available-for-sale marketable securities, Fair Market Value	211,956	312,116
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	5,605	1,018
Commercial Paper	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	88,884	70,431
Available-for-sale marketable securities, Unrealized Gain	12	9
Available-for-sale marketable securities, Unrealized (Loss)	-5	-6
Available-for-sale marketable securities, Fair Market Value	88,891	70,434
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	25,169	25,209
Corporate Debt Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	44,132	53,405
Available-for-sale marketable securities, Unrealized Gain	905	2,414
Available-for-sale marketable securities, Unrealized (Loss)	-1,055	-64
Available-for-sale marketable securities, Fair Market Value	43,982	55,755
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	16,439	23,255
Equity And Debt Mutual Funds	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	9,843	8,767
Available-for-sale marketable securities, Unrealized Gain	2,315	961
Available-for-sale marketable securities, Unrealized (Loss)	-36	-11
Available-for-sale marketable securities, Fair Market Value	12,122	9,717
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	595	600
Certificates Of Deposit And Time Deposits	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	261	1,627
Available-for-sale marketable securities, Fair Market Value	261	1,627
Non-U.S. Government Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	80	84
Available-for-sale marketable securities, Fair Market Value	$80	$84

Schedule_of_Reported_Available

Schedule of Reported Available for Sale Marketable Securities (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	$584,299	$663,625
Available-for-sale marketable securities, Unrealized Gain	3,514	3,862
Available-for-sale marketable securities, Unrealized (Loss)	-1,392	-99
Available-for-sale marketable securities, Fair Market Value	586,421	667,388
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	150,973	59,100
Marketable securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	384,180	431,324
Available-for-sale marketable securities, Unrealized Gain	168	203
Available-for-sale marketable securities, Unrealized (Loss)	-14	-11
Available-for-sale marketable securities, Fair Market Value	384,334	431,516
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	37,823	41,110
Long-term marketable securities	'	'
Schedule of Available-for-sale Securities	'	'
Available-for-sale marketable securities, Cost	200,119	232,301
Available-for-sale marketable securities, Unrealized Gain	3,346	3,659
Available-for-sale marketable securities, Unrealized (Loss)	-1,378	-88
Available-for-sale marketable securities, Fair Market Value	202,087	235,872
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$113,150	$17,990

Contractual_Maturities_of_Avai

Contractual Maturities of Available-for-Sale Marketable Securities (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	$584,299	$663,625
Available for sale securities, Fair Market Value	586,421	667,388
Due In One Year Or Less	'	'
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	384,180	'
Available for sale securities, Fair Market Value	384,334	'
Due After One Year Through Five Years	'	'
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	173,407	'
Available for sale securities, Fair Market Value	175,657	'
Due After Five Years Through Ten Years	'	'
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	3,131	'
Available for sale securities, Fair Market Value	3,188	'
Due After Ten Years	'	'
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	23,581	'
Available for sale securities, Fair Market Value	23,242	'
Available-for-sale Securities	'	'
Schedule of Available-for-sale Securities	'	'
Available for sale securities, Cost	584,299	'
Available for sale securities, Fair Market Value	$586,421	'

Schedule_of_Effect_of_Derivati

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012	Dec. 31, 2012
Fair Value, Option, Quantitative Disclosures	'	'	'	'	'
Derivatives asset not designated as hedging instruments	$276	'	$276	'	$121
Foreign exchange contracts derivatives not designated as hedging instruments, Gains (Losses) Recognized in Statement of Operations	1	-1,197	4,068	-677	'
Interest Expense and Other	'	'	'	'	'
Fair Value, Option, Quantitative Disclosures	'	'	'	'	'
Foreign exchange contracts derivatives not designated as hedging instruments, Gains (Losses) Recognized in Statement of Operations	1	-1,197	4,068	-677	'
Not Designated as Hedging Instrument | Foreign Exchange Contract | Other current assets	'	'	'	'	'
Fair Value, Option, Quantitative Disclosures	'	'	'	'	'
Derivatives asset not designated as hedging instruments	$276	'	$276	'	$121

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

Mar. 31, 2009

Mar. 30, 2012

Sep. 29, 2013

Sep. 30, 2012

Dec. 31, 2012

Sep. 29, 2013

Sep. 30, 2012

Sep. 29, 2013

Sep. 30, 2012

Mar. 31, 2009

Sep. 29, 2013

Apr. 30, 2009

Mar. 31, 2009

Sep. 29, 2013

Sep. 29, 2013

Nov. 08, 2013

Y

Convertible Notes Hedge Warrant

Convertible Notes Hedge Warrant

Convertible Notes Hedge Warrant

Convertible Notes Hedge Warrant

Convertible Notes Hedge Warrant

Convertible Senior Notes

4.50% Convertible Senior Notes Due March 15, 2014

4.50% Convertible Senior Notes Due March 15, 2014

4.50% Convertible Senior Notes Due March 15, 2014

4.50% Convertible Senior Notes Due March 15, 2014

4.50% Convertible Senior Notes Due March 15, 2014

D

Subsequent Event

Debt Instrument

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Borrowings from local bank

$10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of loan, years

5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding loan principal amount

'

'

2,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate principal amount

'

'

189,998,000

'

190,000,000

'

'

'

'

'

'

190,000,000

'

'

'

'

Senior notes maturity date

'

'

'

'

'

'

'

'

'

'

'

'March 15, 2014

'

'

'

'

Initial conversion rate in number of shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

182.65

'

Additional aggregate principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000

'

Initial debt conversion price

'

'

$5.48

'

'

$7.67

$7.67

$7.67

$7.67

$7.67

'

'

$5.48

'

'

'

Debt conversion premium percentage

'

'

'

'

'

'

'

'

'

'

'

'

25.00%

'

'

'

Last reported sale price per share of debt

'

'

'

'

'

'

'

'

'

'

'

'

$4.38

'

'

'

Initial conversion rate

'

'

'The Notes may be converted, at the option of the holder, under certain circumstances and during certain periods, at an initial conversion rate of approximately 182.65 shares of Teradyne's common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $5.48, a 25% conversion premium based on the last reported sale price of $4.38 per share of Teradyne's common stock on March 31, 2009.

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold trading days

'

'

'

'

'

'

'

'

'

'

'

'

'

20

'

'

Threshold consecutive trading days

'

'

'

'

'

'

'

'

'

'

'

'

'

'30 days

'

'

Threshold percentage of stock price trigger

'

'

'

'

'

'

'

'

'

'

'

'

'

130.00%

'

'

Stock price trigger

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2,000

Antidilution adjustments, shares

'

'

34,703,196

'

'

34,700,000

34,700,000

34,700,000

34,700,000

'

'

'

'

'

'

'

Convertible note hedges

'

'

64,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Strike price per share of warrant

$7.67

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of warrant price in excess of closing price of common stock

75.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from warrants

43,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants conversion premium percentage

75.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized discount

'

'

8,448,000

'

20,104,000

'

'

'

'

'

8,400,000

'

'

'

'

'

Amortization period of unamortized discount, months

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

Carrying amount of equity component

'

'

63,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument conversion price

'

'

$5.48

'

'

'

'

'

'

'

'

'

'

'

'

'

If-converted value of notes

'

'

$579,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Components_of_Convertible_Seni

Components of Convertible Senior Notes (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Instrument	'	'
Debt principal	$189,998	$190,000
Unamortized debt discount	8,448	20,104
Net carrying amount of the convertible debt	$181,550	$169,896

Interest_Expense_on_Convertibl

Interest Expense on Convertible Senior Notes (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Debt Instrument	'	'	'	'
Contractual interest expense	$2,114	$2,114	$6,388	$6,413
Amortization of the discount component and debt issue fees	4,221	3,710	12,266	10,781
Total interest expense on the convertible debt	$6,335	$5,824	$18,654	$17,194

Deferred_Revenue_and_Customer_2

Deferred Revenue and Customer Advances (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Revenue Arrangement	'	'
Maintenance, training and extended warranty	$56,481	$51,198
Customer advances	22,287	39,613
Undelivered elements	9,054	6,773
Total deferred revenue and customer advances	$87,822	$97,584

Other_Accrued_Liabilities_Deta

Other Accrued Liabilities (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Schedule of Accrued Liabilities [Line Items]	'	'	'	'
Balance at beginning of period	$7,351	$11,047	$9,786	$8,154
Accruals for warranties issued during the period	3,674	4,118	8,781	13,543
Adjustments related to pre-existing warranties	-524	1,226	-2,323	1,369
Settlements made during the period	-2,470	-3,813	-8,213	-10,488
Balance at end of period	8,031	12,578	8,031	12,578
Balance at beginning of period	34,854	20,754	26,987	12,742
Deferral of new extended warranty revenue	5,586	8,733	17,791	21,015
Recognition of extended warranty deferred revenue	-4,120	-2,007	-8,458	-6,277
Balance at end of period	$36,320	$27,480	$36,320	$27,480

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)	9 Months Ended		12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Stock options term	'7 years	'	'
Restricted stock unit awards to employees	1.9	1.7	'
Weighted average grant date fair value of restricted stock units granted	$16.60	$16.73	'
Number of service-based stock options granted to executive officers	0.2	0.2	'
Weighted average grant date fair value of stock options granted to executive officers	$6.09	$6.85	'
Price paid by employees for common stock purchased through employee stock purchase plan as percentage of stock price	85.00%	'	85.00%
Restricted Stock Units | Employees	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Period of stock granted to employees and executive officers vest in equal installments	'4 years	'	'
Stock Options	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Period of stock granted to employees and executive officers vest in equal installments	'4 years	'	'
Stock Purchase Rights	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'	'
Weighted average grant date fair value of stock options granted to executive officers	'	$3.75	'

Black_Scholes_Option_Pricing_M

Black Scholes Option Pricing Model (Detail) (Stock Options)	9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012
Stock Options	'	'
Share-based Compensation Arrangement by Share-based Payment Award	'	'
Expected life (years)	'4 years	'3 years 6 months
Interest rate	0.60%	0.40%
Volatility-historical	46.80%	56.00%
Dividend yield	0.00%	0.00%

Schedule_of_Estimated_Fair_Val

Schedule of Estimated Fair Value of Stock Options Assumptions (Detail) (Stock Purchase Rights)	9 Months Ended
	Sep. 30, 2012
Stock Purchase Rights	'
Share-based Compensation Arrangement by Share-based Payment Award	'
Expected life (years)	'6 months
Interest rate	0.11%
Volatility-historical	42.70%
Dividend yield	0.00%

Changes_in_Accumulated_Other_C

Changes in Accumulated Other Comprehensive Income Balances (Detail) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013		Sep. 30, 2012	Sep. 29, 2013		Sep. 30, 2012
Other Comprehensive Income (Loss) [Line Items]	'		'	'		'
Beginning balance	'		'	$5,820	[1]	'
Other comprehensive income before reclassifications	'		'	-1,019		'
Amounts reclassified from accumulated other comprehensive income	-311		-185	-946		-858
Other comprehensive income (loss)	576		1,074	-1,965		1,597
Ending balance	3,855	[1]	'	3,855	[1]	'
Unrealized Gains on Marketable Securities	'		'	'		'
Other Comprehensive Income (Loss) [Line Items]	'		'	'		'
Beginning balance	'		'	2,925	[1]	'
Other comprehensive income before reclassifications	'		'	-1,019		'
Amounts reclassified from accumulated other comprehensive income	'		'	-621		'
Other comprehensive income (loss)	'		'	-1,640		'
Ending balance	1,285	[1]	'	1,285	[1]	'
Retirement Plans Prior Service Credit	'		'	'		'
Other Comprehensive Income (Loss) [Line Items]	'		'	'		'
Beginning balance	'		'	2,895	[1]	'
Amounts reclassified from accumulated other comprehensive income	'		'	-325		'
Other comprehensive income (loss)	'		'	-325		'
Ending balance	$2,570	[1]	'	$2,570	[1]	'
[1]	Net of tax of $835 for unrealized gains on marketable securities and $(125) for retirement plans prior service credit.

Changes_in_Accumulated_Other_C1

Changes in Accumulated Other Comprehensive Income Balances (Parenthetical) (Detail) (USD $)	Sep. 29, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Comprehensive Income (Loss) [Line Items]	'	'
Unrealized gains on marketable securities, tax	$835	$835
Retirement plans prior service benefit, tax	($125)	($125)

Reclassification_Out_of_Accumu

Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013		Sep. 30, 2012		Sep. 29, 2013		Sep. 30, 2012
Other Comprehensive Income (Loss) [Line Items]	'		'		'		'
Unrealized gains	$202		$93		$621		$583
Net income	202		93		621		583
Prior service benefit	109	[1]	92	[1]	325	[1]	275	[1]
Net income	109		92		325		275
Total reclassifications	$311		$185		$946		$858
[1]	The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note M "Retirement Plans."

Schedule_of_Amortizable_Intang

Schedule of Amortizable Intangible Assets (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	$538,366	$537,366
Accumulated Amortization	272,661	218,499
Net Carrying Amount	265,705	318,867
Weighted Average Useful Life, years	'7 years	'7 years
Developed technology	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	358,555	357,555
Accumulated Amortization	180,960	143,126
Net Carrying Amount	177,595	214,429
Weighted Average Useful Life, years	'6 years 3 months 18 days	'6 years 3 months 18 days
Customer Relationships And Service And Software Maintenance Contracts	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	144,971	144,971
Accumulated Amortization	77,139	63,464
Net Carrying Amount	67,832	81,507
Weighted Average Useful Life, years	'8 years	'8 years
Trade Names And Trademarks	'	'
Finite-Lived Intangible Assets	'	'
Gross Carrying Amount	33,840	33,840
Accumulated Amortization	13,562	10,909
Net Carrying Amount	20,278	22,931
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		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Goodwill and Intangible Assets Disclosure [Line Items]	'	'	'	'
Aggregate intangible asset amortization expense	$18,064	$18,429	$54,163	$55,287

Schedule_of_Estimated_Intangib

Schedule of Estimated Intangible Asset Amortization Expense (Detail) (USD $)	Sep. 29, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets	'
2013 (remainder)	$18,052
2014	69,213
2015	52,462
2016	52,462
2017	$46,304

Net_Income_Per_Common_Share_De

Net Income Per Common Share (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 29, 2013		Sep. 30, 2012		Sep. 29, 2013		Sep. 30, 2012
Net Income Loss Per Common Share	'		'		'		'
Net income for basic and diluted net income per share	$69,459		$88,641		$142,604		$233,592
Weighted average common shares-basic	191,307		187,364		190,521		186,592
Incremental shares from assumed conversion of convertible notes	23,257	[1]	21,890	[1]	23,303	[1]	22,397	[1]
Convertible note hedge warrant shares	18,678	[2]	16,765	[2]	18,742	[2]	17,474	[2]
Restricted stock units	1,102		1,423		1,000		1,413
Stock options	1,465		1,735		1,564		2,075
Employee stock purchase rights	19		33		35		52
Dilutive potential common shares	44,521		41,846		44,644		43,411
Weighted average common shares-diluted	235,828		229,210		235,165		230,003
Net income per common share-basic	$0.36		$0.47		$0.75		$1.25
Net income per common share-diluted	$0.29		$0.39		$0.61		$1.02
[1]	Incremental shares from assumed conversion of the convertible notes for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the conversion price of $5.48, multiplied by the 34.7 million shares that would be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, is divided by the average Teradyne stock price for the period.
[2]	Convertible note hedge warrant shares for the three and nine months ended September 29, 2013 and September 30, 2012 are calculated using the difference between the average Teradyne stock price for the period and the warrant price of $7.67, multiplied by the 34.7 million shares that would be issued upon conversion. The result of this calculation, representing the total intrinsic value of the warrant, is divided by the average Teradyne stock price for the period.

Net_Income_Per_Common_Share_Pa

Net Income Per Common Share (Parenthetical) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012	Mar. 31, 2009
Net Income Loss Per Common Share	'	'	'	'	'
Initial debt conversion price	$5.48	'	$5.48	'	'
Shares that would be issued upon conversion	'	'	34,703,196	'	'
Convertible Notes	'	'	'	'	'
Net Income Loss Per Common Share	'	'	'	'	'
Initial debt conversion price	$5.48	$5.48	$5.48	$5.48	'
Shares that would be issued upon conversion	34,700,000	34,700,000	34,700,000	34,700,000	'
Convertible Notes Hedge Warrant	'	'	'	'	'
Net Income Loss Per Common Share	'	'	'	'	'
Initial debt conversion price	$7.67	$7.67	$7.67	$7.67	$7.67
Shares that would be issued upon conversion	34,700,000	34,700,000	34,700,000	34,700,000	'

Net_Income_Per_Common_Share_Ad

Net Income Per Common Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Net Income Loss Per Common Share	'	'	'	'
Exercise of stock options	0.4	0.3	0.4	0.3
Restricted stock units exercise to purchase shares	'	0.1	'	0.4

Restructuring_and_Other_Additi

Restructuring and Other - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012
	Employee	Employee
Restructuring Cost and Reserve	'	'
Severance benefit and charges	$1.30	$0.70
Reduction in employees head count	40	9
Change in estimated exit costs related to leased facility	-0.4	'
Accrual for severance and benefits	0.5	'
Business acquisition, contingent consideration	8.4	'
System Test	'	'
Restructuring Cost and Reserve	'	'
Severance benefit and charges	1	0.5
Reduction in employees head count	'	7
Wireless Test	'	'
Restructuring Cost and Reserve	'	'
Severance benefit and charges	'	0.2
Reduction in employees head count	'	2
Semiconductor Test	'	'
Restructuring Cost and Reserve	'	'
Severance benefit and charges	$0.30	'

Schedule_of_Restructuring_and_

Schedule of Restructuring and Other Net (Detail) (USD $)	3 Months Ended			12 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Restructuring Cost and Reserve	'	'	'	'
Ending balance	$453	'	'	'
Pre-2012 Activities	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Beginning Balance	597	796	1,084	2,187
Change in estimate	-448	'	-105	'
Cash payments	-149	-199	-183	-1,103
Ending balance	'	597	796	1,084
Q3 2012 Activity	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Beginning Balance	'	'	243	'
Provision	'	'	'	687
Cash payments	'	'	-243	-444
Ending balance	'	'	'	243
Q3 2013 Activity	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Provision	1,337	'	'	'
Cash payments	-884	'	'	'
Ending balance	453	'	'	'
Employee Serverance And Benefits	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Ending balance	453	'	'	'
Employee Serverance And Benefits | Pre-2012 Activities	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Beginning Balance	'	'	'	325
Cash payments	'	'	'	-325
Employee Serverance And Benefits | Q3 2012 Activity	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Beginning Balance	'	'	243	'
Provision	'	'	'	687
Cash payments	'	'	-243	-444
Ending balance	'	'	'	243
Employee Serverance And Benefits | Q3 2013 Activity	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Provision	1,337	'	'	'
Cash payments	-884	'	'	'
Ending balance	453	'	'	'
Facility Exit Costs | Pre-2012 Activities	'	'	'	'
Restructuring Cost and Reserve	'	'	'	'
Beginning Balance	597	796	1,084	1,862
Change in estimate	-448	'	-105	'
Cash payments	-149	-199	-183	-778
Ending balance	'	$597	$796	$1,084

Schedule_of_Net_Periodic_Pensi

Schedule of Net Periodic Pension (Benefit) Costs (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Defined Benefit Plan Disclosure	'	'	'	'
Actuarial (gain) loss	'	'	($1,359)	$4,991
Defined Benefit Pension Plans	'	'	'	'
Defined Benefit Plan Disclosure	'	'	'	'
Service cost	871	685	2,557	2,054
Interest cost	3,350	4,111	10,001	12,333
Expected return on plan assets	-3,664	-4,090	-10,925	-12,269
Amortization of unrecognized prior service cost (benefit)	41	58	123	174
Actuarial (gain) loss	'	1,937	-1,122	5,083
Total net periodic (benefit) cost	598	2,701	634	7,375
Post-Retirement Benefit Plans	'	'	'	'
Defined Benefit Plan Disclosure	'	'	'	'
Service cost	19	17	56	50
Interest cost	86	109	257	328
Amortization of unrecognized prior service cost (benefit)	-150	-150	-449	-449
Actuarial (gain) loss	'	'	-236	-92
Total net periodic (benefit) cost	($45)	($24)	($372)	($163)

Retirement_Plans_Additional_In

Retirement Plans - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 29, 2013	Sep. 29, 2013
	Employee	United States Pension Plans of US Entity, Defined Benefit	Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure	'	'	'
Contribution to defined benefit pension plans	'	$1.30	$1.30
Number of former employees elected to receive lump-sum payment	2,000	'	'
Lump sum payment made for former employees	$52	'	'

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 29, 2013
Purchase Commitment, Excluding Long-term Commitment	'
Aggregate purchase commitments	243.3
Purchase commitments less than one year	231.5
Maximum	'
Purchase Commitment, Excluding Long-term Commitment	'
Purchase commitments period	'1 year

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Income Taxes [Line Items]	'	'	'	'
Effective tax rate	21.00%	14.00%	14.00%	21.00%
U.S. statutory federal tax rate	35.00%	'	35.00%	'

Schedule_of_Segment_Informatio

Schedule of Segment Information (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013		Sep. 30, 2012		Sep. 29, 2013		Sep. 30, 2012
Segment Reporting Information [Line Items]	'		'		'		'
Net revenues	$433,376		$463,394		$1,142,632		$1,408,346
Income (loss) before income taxes	87,552	[1],[2]	103,025	[1],[2]	166,483	[1],[2]	296,261	[1],[2]
Semiconductor Test	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Net revenues	304,131		310,979		808,068		943,625
Income (loss) before income taxes	68,932	[1],[2]	55,348	[1],[2]	141,304	[1],[2]	181,594	[1],[2]
Wireless Test	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Net revenues	93,132		118,571		226,116		261,827
Income (loss) before income taxes	27,575	[1],[2]	58,902	[1],[2]	41,491	[1],[2]	97,729	[1],[2]
System Test	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Net revenues	36,113		33,844		108,448		202,894
Income (loss) before income taxes	-2,462	[1],[2]	-2,642	[1],[2]	-153	[1],[2]	30,964	[1],[2]
Corporate And Eliminations	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Income (loss) before income taxes	($6,493)	[1],[2]	($8,583)	[1],[2]	($16,159)	[1],[2]	($14,026)	[1],[2]
[1]	Pension and post retirement actuarial gains and losses, 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 and nine months ended September 29, 2013 and September 30, 2012 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		9 Months Ended
In Thousands, unless otherwise specified	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Semiconductor Test	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Cost of revenues-provision for excess and obsolete inventory	$1,378	$3,085	$1,878	$9,254
Restructuring and other	282	-4	416	315
Total	1,660	3,081	2,294	9,569
Wireless Test	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Cost of revenues-provision for excess and obsolete inventory	2,059	2,018	6,125	4,134
Cost of revenues-inventory step-up	'	'	'	6,089
Restructuring and other	'	236	82	236
Total	2,059	2,254	6,207	10,459
System Test	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Cost of revenues-provision for excess and obsolete inventory	404	378	1,613	3,020
Restructuring and other	1,055	451	1,430	451
Total	1,459	829	3,043	3,471
Corporate And Eliminations	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Restructuring and other	-448	'	-448	-8,406
Total	($448)	'	($448)	($8,406)

Stock_Repurchase_Program_Addit

Stock Repurchase Program - Additional Information (Detail) (USD $)	1 Months Ended	34 Months Ended
In Millions, except Per Share data, unless otherwise specified	Nov. 30, 2010	Sep. 29, 2013
Stock Repurchase Program	'	'
Stock repurchase program, authorized amount	$200	'
Repurchase of stock, shares	'	2.6
Repurchase of stock, value	'	$31.20
Common stock average price	'	$11.84

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2013	Nov. 01, 2013	Oct. 25, 2013	Oct. 25, 2013
		Scenario, Forecast	Subsequent Event	Subsequent Event	Subsequent Event
				ZTEC	ZTEC
					Maximum
Subsequent Event [Line Items]	'	'	'	'	'
Acquisition price	'	'	'	$15,000,000	'
Amount payable upon completion of performance target	388,000	'	'	'	5,000,000
Proceeds from sale of equity interest	'	'	34,200,000	'	'
Additional proceeds held in escrow	'	'	5,200,000	'	'
Amount of gain will record	'	$34,200,000	'	'	'