Cadence Design Systems (CDNS) 10-Q 24 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 28, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	CADENCE DESIGN SYSTEMS INC
Entity Central Index Key	813672
Document Type	10-Q
Document Period End Date	28-Sep-13
Amendment Flag	FALSE
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	-16
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	287,743,419

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Current Assets:
Cash and cash equivalents	$620,403	$726,357
Short-term investments	96,019	100,704
Receivables, net of allowances of $144 and $85, respectively	101,896	97,821
Inventories	45,877	36,163
2015 notes hedges	292,511	303,154
Prepaid expenses and other	117,457	127,036
Total current assets	1,274,163	1,391,235
Property, plant and equipment, net of accumulated depreciation of $564,416 and $635,450, respectively	241,965	244,439
Goodwill	456,267	233,266
Acquired intangibles, net of accumulated amortization of $128,004 and $104,351, respectively	323,807	184,938
Long-term receivables	3,994	7,559
Other assets	257,191	225,566
Total assets	2,557,387	2,287,003
Current Liabilities:
Revolving credit facility	50,000	0
Convertible notes	463,837	447,011
2015 notes embedded conversion derivative	292,511	303,154
Accounts payable and accrued liabilities	193,445	171,318
Current portion of deferred revenue	297,897	295,787
Total current liabilities	1,297,690	1,217,270
Long-Term Liabilities:
Long-term portion of deferred revenue	48,229	50,529
Other long-term liabilities	115,262	104,033
Total long-term liabilities	163,491	154,562
Commitments and contingencies
Stockholders' Equity:
Common stock and capital in excess of par value	1,739,677	1,721,556
Treasury stock, at cost	-141,344	-200,786
Accumulated deficit	-523,011	-649,549
Accumulated other comprehensive income	20,884	43,950
Total stockholders’ equity	1,096,206	915,171
Total liabilities and stockholders’ equity	$2,557,387	$2,287,003

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Statement of Financial Position [Abstract]
Allowance for receivables	$144	$85
Accumulated depreciation on property, plant and equipment	564,416	635,450
Accumulated amortization on acquired intangibles assets	$128,004	$104,351

Condensed_Consolidated_Income_

Condensed Consolidated Income Statements (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Revenue:
Product and maintenance	$341,601	$310,118	$1,007,855	$893,916
Service	25,046	28,415	75,539	86,923
Total revenue	366,647	338,533	1,083,394	980,839
Costs and Expenses:
Cost of product and maintenance	32,546	34,461	90,488	94,079
Cost of service	17,190	16,809	50,682	53,254
Marketing and sales	98,094	82,461	283,773	246,674
Research and development	138,078	115,078	398,557	335,703
General and administrative	27,582	26,350	91,833	84,364
Amortization of acquired intangibles	5,141	3,876	14,259	11,305
Restructuring and other charges	86	57	2,594	49
Total costs and expenses	318,717	279,092	932,186	825,428
Income from operations	47,930	59,441	151,208	155,411
Interest expense	-9,583	-8,737	-28,373	-25,840
Other income (expense), net	2,535	-131	6,728	5,972
Income before provision (benefit) for income taxes	40,882	50,573	129,563	135,543
Provision (benefit) for income taxes	2,382	-8,011	3,025	9,469
Net income	$38,500	$58,584	$126,538	$126,074
Net income per share - basic (in usd per share)	$0.14	$0.22	$0.46	$0.47
Net income per share - diluted (in usd per share)	$0.13	$0.21	$0.43	$0.45
Weighted average common shares outstanding - basic (in shares)	278,977	271,350	277,034	269,643
Weighted average common shares outstanding - diluted (in shares)	296,958	283,328	294,531	278,760

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Statement of Comprehensive Income [Abstract]
Net income	$38,500	$58,584	$126,538	$126,074
Other comprehensive income (loss), net of tax effects:
Foreign currency translation adjustments	-5,442	1,025	-23,308	-3,808
Changes in unrealized holding gains or losses on available-for-sale securities, net of reclassification adjustment for realized gains and losses	177	-120	-206	-1,141
Changes in defined benefit plan liabilities	66	65	448	120
Total other comprehensive income (loss), net of tax effects	-5,199	970	-23,066	-4,829
Comprehensive income	$33,301	$59,554	$103,472	$121,245

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of period	$726,357	$601,602
Cash flows from operating activities:
Net income	126,538	126,074
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	72,681	67,171
Amortization of debt discount and fees	19,102	17,480
Stock-based compensation	47,487	34,285
Gain on investments, net	-4,035	-2,222
Deferred income taxes	-6,425	-14,107
Other non-cash items	2,183	3,578
Changes in operating assets and liabilities, net of effect of acquired businesses:
Receivables	2,192	24,276
Inventories	-10,005	6,936
Prepaid expenses and other	26,927	1,547
Other assets	-46,651	-3,101
Accounts payable and accrued liabilities	18,277	-1,714
Deferred revenue	-5,474	-38,230
Other long-term liabilities	5,644	-1,855
Net cash provided by operating activities	248,441	220,118
Cash flows from investing activities:
Purchases of available-for-sale securities	-84,000	-101,248
Proceeds from the sale of available-for-sale securities	59,014	5,936
Proceeds from the maturity of available-for-sale securities	30,506	1,500
Proceeds from the sale of long-term investments	6,200	44
Purchases of property, plant and equipment	-35,950	-25,932
Investment in venture capital partnerships and equity investments	0	-250
Cash paid in business combinations and asset acquisitions, net of cash acquired	-392,825	-66,432
Net cash used for investing activities	-417,055	-186,382
Cash flows from financing activities:
Proceeds from revolving credit facility	100,000	0
Payment on revolving credit facility	-50,000	0
Payment of convertible notes	-78	0
Principal payments on receivable financing	-2,526	-2,907
Payment of acquisition-related contingent consideration	677	39
Tax effect related to employee stock transactions allocated to equity	9,494	5,790
Proceeds from issuance of common stock	40,691	28,755
Stock received for payment of employee taxes on vesting of restricted stock	-19,461	-13,457
Net cash provided by financing activities	77,443	18,142
Effect of exchange rate changes on cash and cash equivalents	14,783	4,381
Increase (decrease) in cash and cash equivalents	-105,954	47,497
Cash and cash equivalents at end of period	620,403	649,099
Supplemental cash flow information:
Cash paid for interest	6,538	5,677
Cash paid for taxes, net	5,281	12,481
Non-cash investing and financing activities:
Stock options assumed for acquisition	529	0
Available-for-sale securities received from customer	$232	$20

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 28, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION
	The condensed consolidated financial statements included in this Quarterly Report on Form 10-Q have been prepared by Cadence Design Systems, Inc., or Cadence, without audit, pursuant to the rules and regulations of the United States Securities and Exchange Commission, or the SEC. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to such rules and regulations. However, Cadence believes that the disclosures contained in this Quarterly Report on Form 10-Q comply with the requirements of Section 13(a) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, for a Quarterly Report on Form 10-Q and are adequate to make the information presented not misleading. These condensed consolidated financial statements are meant to be, and should be, read in conjunction with the consolidated financial statements and the Notes thereto included in Cadence’s Annual Report on Form 10-K for the fiscal year ended December 29, 2012. In the condensed consolidated income statements for the three and nine months ended September 28, 2013, Cadence combined product and maintenance revenue because product and maintenance revenue is generally recognized from agreements that require customers to purchase both the product and associated maintenance in a bundled offering. Cadence reclassified prior period product and maintenance revenue balances to conform to the current period presentation. Certain other prior period balances have also been reclassified to conform to current period presentation.
	The unaudited condensed consolidated financial statements included in this Quarterly Report on Form 10-Q reflect all adjustments (which include only normal, recurring adjustments and those items discussed in these Notes) that are, in the opinion of management, necessary to state fairly the results of operations, cash flows and financial position for the periods and dates presented. The results for such periods are not necessarily indicative of the results to be expected for the full fiscal year.
	Preparation of the condensed consolidated financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

Debt

Debt	9 Months Ended
	Sep. 28, 2013
Debt Disclosure [Abstract]
DEBT	DEBT
	Cadence’s outstanding debt as of September 28, 2013 and December 29, 2012 was as follows:
		28-Sep-13									December 29, 2012
		(In thousands)
		Principal			Unamortized Discount			Carrying Value			Principal			Unamortized Discount			Carrying Value
	2015 Notes	$	350,000		$	(29,275	)	$	320,725		$	350,000		$	(41,181	)	$	308,819
	2013 Notes	144,461			(1,449		)	143,012			144,461			(6,447		)	138,014
	2023 Notes	100			—			100			178			—			178
	Revolving credit facility	50,000			—			50,000			—			—			—
	Total outstanding debt	$	544,561		$	(30,724	)	$	513,837		$	494,639		$	(47,628	)	$	447,011
	2015 Notes
	In June 2010, Cadence issued $350.0 million principal amount of 2.625% Cash Convertible Senior Notes Due 2015, or the 2015 Notes. At maturity, the holders of the 2015 Notes will be entitled to receive the principal amount of the 2015 Notes plus accrued interest. The 2015 Notes are convertible into cash prior to maturity upon the occurrence of certain conditions described in the table below. To the extent that the 2015 Notes are convertible prior to maturity and a holder of the 2015 Notes elects to convert its notes prior to maturity, that note holder will be entitled to receive cash equal to the principal amount of the notes plus any additional conversion value as described in the table below under the heading "Conversion feature."
	Cadence entered into hedge transactions, or the 2015 Notes Hedges, in connection with the issuance of the 2015 Notes. The purpose of the 2015 Notes Hedges was to limit Cadence’s exposure to the additional cash payments above the principal amount of the 2015 Notes that may be due to the holders. As a result of the 2015 Notes Hedges, Cadence’s maximum expected cash exposure upon conversion of the 2015 Notes is the $350.0 million principal balance of the notes. In June 2010, Cadence also sold warrants in separate transactions, or the 2015 Warrants. As a result of the 2015 Warrants, Cadence will experience dilution to its diluted earnings per share if its average closing stock price exceeds $10.78 for any fiscal quarter. To the extent that Cadence’s stock price exceeds $10.78 at expiration of the 2015 Warrants, Cadence will issue shares to net settle the 2015 Warrants.
	A summary of key terms of the 2015 Notes is as follows:
			2015 Notes
			(In thousands, except percentages and per share amounts)
	Outstanding principal maturity value – at September 28, 2013		$350,000
	Contractual interest rate		2.63%
	Contractual maturity date		June 1, 2015
	Initial conversion rate		132.5205 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $7.55 per share of Cadence common stock.
	Conversion feature (in addition to principal amount payable in cash)		Cash to the extent Cadence’s stock price exceeds approximately $7.55 per share, calculated based on the applicable conversion rate multiplied by the volume weighted average price of Cadence common stock over a specified period.
	Early conversion conditions (or the Early Conversion Conditions)		• Closing stock price greater than $9.81 for at least 20 of the last 30 trading days in a fiscal quarter (convertible only for subsequent quarter);
			• Specified corporate transactions; or
			• Note trading price falls below a calculated minimum.
	Conversion immediately preceding maturity		From March 1, 2015 until the second trading day immediately preceding the maturity date, holders may convert their 2015 Notes at any time into cash as described above under “Conversion feature.”
	Redemption at Cadence’s option prior to maturity		None.
	Fundamental change put right		Upon certain fundamental corporate changes prior to maturity, the 2015 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest.
	Make-whole premium		Upon certain fundamental changes prior to maturity, if Cadence’s stock price were between $6.16 and $40.00 per share at that time, the 2015 Note holders would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
	Financial covenants		None.
	Impact of Early Conversion Conditions on Financial Statements
	The 2015 Notes are convertible into cash from September 29, 2013 through December 28, 2013 because Cadence’s closing stock price exceeded $9.81 for at least 20 days in the 30-day period prior to September 28, 2013. Accordingly, the net balance of the 2015 Notes of $320.7 million is classified as a current liability on Cadence’s condensed consolidated balance sheet as of September 28, 2013. The classification of the 2015 Notes as current or long-term on the condensed consolidated balance sheet is evaluated at each balance sheet date and may change from time to time depending on whether Cadence’s closing stock price has exceeded $9.81 during the periods specified in the table above under “Early conversion conditions.” In the event that none of the 2015 Notes Early Conversion Conditions have been met in a future fiscal quarter prior to the one-year period immediately preceding the maturity date, Cadence will classify its net liability under the 2015 Notes as a long-term liability on the consolidated balance sheet as of the end of that fiscal quarter.
	If the note holders elect to convert their 2015 Notes prior to maturity, any unamortized discount and transaction fees will be expensed at the time of conversion. If the entire outstanding principal amount had been converted on September 28, 2013, Cadence would have recorded an expense of $33.3 million associated with the conversion, comprised of $29.3 million of unamortized debt discount and $4.0 million of unamortized transaction fees.
	As of September 28, 2013, the if-converted value of the 2015 Notes to the note holders of approximately $628.5 million exceeded the principal amount of $350.0 million. The fair value of the 2015 Notes was $639.4 million as of September 28, 2013 and $640.1 million as of December 29, 2012. The 2015 Notes currently trade at a premium to the if-converted value of the notes. As of September 28, 2013, none of the note holders had elected to convert their 2015 Notes.
	2015 Notes Embedded Conversion Derivative
	The conversion feature of the 2015 Notes, or the 2015 Notes Embedded Conversion Derivative, requires bifurcation from the 2015 Notes and is accounted for as a derivative liability. The fair value of the 2015 Notes Embedded Conversion Derivative at the time of issuance of the 2015 Notes was $76.6 million and was recorded as original debt discount for purposes of accounting for the debt component of the 2015 Notes. This discount is amortized as interest expense using the effective interest method over the term of the 2015 Notes. The 2015 Notes Embedded Conversion Derivative is carried on the condensed consolidated balance sheet at its estimated fair value. The fair value was $292.5 million as of September 28, 2013 and $303.2 million as of December 29, 2012.
	2015 Notes Hedges
	The 2015 Notes Hedges expire on June 1, 2015 and must be settled in cash. The aggregate cost of the 2015 Notes Hedges was $76.6 million. The 2015 Notes Hedges are accounted for as derivative assets and are carried on the condensed consolidated balance sheet at their estimated fair value. The 2015 Note Hedges fair value was $292.5 million as of September 28, 2013 and $303.2 million as of December 29, 2012. The 2015 Notes Embedded Conversion Derivative liability and the 2015 Notes Hedges asset are adjusted to fair value each reporting period and unrealized gains and losses are reflected in the condensed consolidated income statements. The 2015 Notes Embedded Conversion Derivative and the 2015 Notes Hedges are designed to have similar fair values. Accordingly, the changes in the fair values of these instruments offset during the three and nine months ended September 28, 2013 and September 29, 2012 and did not have a net impact on the condensed consolidated income statements for the respective periods.
	The classification of the 2015 Notes Embedded Conversion Derivative liability and the 2015 Notes Hedges asset as current or long-term on the condensed consolidated balance sheet corresponds with the classification of the 2015 Notes, is evaluated at each balance sheet date and may change from time to time depending on whether the closing stock price Early Conversion Condition is met for a particular quarter.
	2015 Warrants
	In June 2010, Cadence sold the 2015 Warrants in separate transactions for the purchase of up to approximately 46.4 million shares of Cadence’s common stock at a strike price of $10.78 per share, for total proceeds of $37.5 million, which was recorded as an increase in stockholders’ equity. The 2015 Warrants expire on various dates from September 2015 through December 2015 and must be settled in net shares of Cadence’s common stock. Therefore, upon expiration of the 2015 Warrants, Cadence will issue shares of common stock to the purchasers of the 2015 Warrants that represent the value by which the price of the common stock exceeds the strike price stipulated within the particular warrant agreement.
	The effective interest rate and components of interest expense of the 2015 Notes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands, except percentages)
	Effective interest rate	8.1		%	8.1		%	8.1		%	8.1		%
	Contractual interest expense	$	2,289		$	2,289		$	6,867		$	6,867
	Amortization of debt discount	$	4,045		$	3,737		$	11,906		$	10,968
	2013 Notes
	In December 2006, Cadence issued $250.0 million principal amount of 1.500% Convertible Senior Notes Due December 15, 2013, or the 2013 Notes. During 2010, Cadence repurchased a portion of the 2013 Notes. As of September 28, 2013, the remaining principal maturity value of the 2013 Notes was $144.5 million.
	At maturity, the holders of the 2013 Notes will be entitled to receive the principal amount of the 2013 Notes plus accrued interest. The 2013 Notes are convertible into a combination of cash and shares of Cadence common stock upon the occurrence of certain conditions described in the table below. To the extent that the 2013 Notes are convertible prior to maturity and a holder of the 2013 Notes elects to convert its notes prior to maturity, that note holder will be entitled to receive cash for the principal amount of the notes plus shares for any additional conversion value as described in the table below under the heading “Conversion feature.” As of September 28, 2013, the 2013 Notes were not convertible.
	Cadence entered into hedge transactions, or the 2013 Notes Hedges, in connection with the issuance of the 2013 Notes. Pursuant to the 2013 Notes Hedges, Cadence has the option to receive the amount of shares that may be owed to the 2013 Notes holders. The purpose of the 2013 Notes Hedges was to limit Cadence’s exposure to the dilution that may result from the issuance of shares upon conversion of the notes. In December 2006, Cadence also sold warrants in separate transactions, or the 2013 Warrants. As a result of the 2013 Warrants, Cadence will experience dilution to its diluted earnings per share to the extent its average closing stock price exceeds $31.50 for any fiscal quarter. If Cadence’s stock price is above $31.50 at the expiration of the 2013 Warrants, Cadence will issue shares to settle the 2013 Warrants.
	A summary of key terms of the 2013 Notes is as follows:
			2013 Notes
			(In thousands, except percentages and per share amounts)
	Principal maturity value – at issuance		$250,000
	Outstanding principal maturity value – at September 28, 2013		$144,461
	Contractual interest rate		1.50%
	Contractual maturity date		15-Dec-13
	Equity component - included in common stock - at September 28, 2013 and December 29, 2012		$63,027
	Initial conversion rate		47.2813 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $21.15 per share of Cadence common stock.
	Conversion feature (in addition to principal amount payable in cash)		Shares to the extent Cadence’s stock price exceeds $21.15 per share, calculated based on the applicable conversion rate multiplied by the volume weighted average price of Cadence common stock over a specified period.
	Early conversion conditions (or the Early Conversion Conditions)		•  Closing stock price greater than $27.50 for at least 20 of the last 30 trading days in a calendar quarter (convertible only for subsequent quarter);
			•  Specified corporate transactions; or
•  Note trading price falls below calculated minimum.
Conversion immediately preceding maturity		From November 1, 2013, and until the trading day immediately preceding the maturity date, holders may convert their 2013 Notes at any time into cash and Cadence shares as described above under “Conversion feature.”
Redemption at Cadence’s option prior to maturity		None.
Fundamental change put right		Upon a fundamental change prior to maturity, the 2013 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest.
Make-whole premium		Upon certain fundamental changes, prior to maturity, if Cadence’s stock price were between $18.00 and $60.00 per share at that time, the 2013 Note holders would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
Financial covenants		None.
Impact of Early Conversion Conditions on Financial Statements
As of September 28, 2013, none of the 2013 Notes Early Conversion Conditions had been met. The 2013 Notes mature on December 15, 2013 and the liability component of the 2013 Notes is classified as a current liability as of September 28, 2013.
As of September 28, 2013, the if-converted value of the 2013 Notes to the note holders did not exceed the principal amount of the 2013 Notes. The total fair value of the 2013 Notes, including the equity component, was $144.7 million as of September 28, 2013 and was $144.1 million as of December 29, 2012.
2013 Notes Hedges
The 2013 Notes Hedges expire on December 15, 2013, and must be settled in net shares of Cadence common stock. Therefore, upon expiration of the 2013 Notes Hedges, the counterparties will deliver shares of common stock to Cadence that represent the value, if any, by which the price of the common stock exceeds the price stipulated within the particular hedge agreement. The aggregate cost of the 2013 Notes Hedges was $67.7 million and was recorded as a reduction to stockholders’ equity. In connection with the purchase of a portion of the 2013 Notes during fiscal 2010, Cadence also sold a portion of the 2013 Notes Hedges representing options to purchase approximately 5.0 million shares of Cadence’s common stock. The estimated fair value of the remaining 2013 Notes Hedges was approximately zero as of September 28, 2013 and $0.7 million as of December 29, 2012. Subsequent changes in the fair value of the 2013 Notes Hedges will not be recognized in the condensed consolidated financial statements as long as the instruments remain classified as equity.
2013 Warrants
In December 2006, Cadence sold the 2013 Warrants in separate transactions, for the purchase of up to 11.8 million shares of Cadence’s common stock at a strike price of $31.50 per share for proceeds of $25.3 million, which was recorded as an increase in stockholders’ equity. In connection with the purchase of some of the 2013 Notes during fiscal 2010, Cadence also purchased some of the 2013 Warrants, reducing the number of shares of Cadence common stock subject to purchase rights by 5.0 million shares. The 2013 Warrants will expire on various dates from February 2014 through April 2014. The 2013 Warrants must be settled in net shares of Cadence’s common stock. Therefore, upon expiration, Cadence will issue shares of common stock to the purchasers of the warrants that represent the value, if any, by which the price of the common stock exceeds the strike price stipulated within the particular warrant agreement.
The effective interest rate and components of interest expense of the 2013 Notes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
	Three Months Ended						Nine Months Ended
	September 28,			September 29,			September 28,			September 29,
	2013			2012			2013			2012
	(In thousands, except percentages)
Effective interest rate	6.4		%	6.4		%	6.4		%	6.4		%
Contractual interest expense	$	540		$	540		$	1,619		$	1,619
Amortization of debt discount	$	1,691		$	1,588		$	4,998		$	4,674
Zero Coupon Zero Yield Senior Convertible Notes Due 2023
In August 2003, Cadence issued $420.0 million principal amount of its Zero Coupon Zero Yield Senior Convertible Notes Due 2023, or the 2023 Notes. As of September 28, 2013 and December 29, 2012, the remaining balance and the total fair value of the 2023 Notes was $0.1 million and $0.2 million, respectively.
Revolving Credit Facility
In December 2012, Cadence entered into a five-year senior secured revolving credit facility. The credit facility provides for borrowings up to $250.0 million, with the right to request increased capacity up to an additional $150.0 million upon the receipt of lender commitments, for total maximum borrowings of $400.0 million.
Any outstanding loans drawn under the credit facility are due at maturity in December 2017. Outstanding amounts may be paid at any time prior to maturity. The facility is secured by certain accounts receivable and certain equity interests in Cadence’s subsidiaries.
Interest accrues based on Cadence’s consolidated leverage ratio. Borrowings may be made at LIBOR plus a margin between 1.25% and 2.00% per annum or at the base rate plus a margin between 0.25% and 1.00% per annum, where in each case the margin is determined by reference to a specified leverage ratio. Interest is payable quarterly. A commitment fee ranging from 0.20% to 0.35% is assessed on the daily average undrawn portion of revolving commitments.
The credit facility contains customary negative covenants that, among other things, restrict Cadence’s ability to incur additional indebtedness, grant liens and make certain investments, make acquisitions, dispose of certain assets and make certain restricted payments, including dividends. In addition, the credit facility contains financial covenants that require Cadence to maintain a leverage ratio not to exceed 3 to 1, and a minimum interest coverage ratio of 3 to 1.
As of September 28, 2013 and December 29, 2012, Cadence had outstanding borrowings under the credit facility of $50.0 million and $0, respectively, and was in compliance with all financial covenants.

Acquisitions_and_AcquisitionRe

Acquisitions and Acquisition-Related Contingent Consideration	9 Months Ended
	Sep. 28, 2013
Business Combinations [Abstract]
ACQUISITIONS AND ACQUISITION-RELATED CONTINGENT CONSIDERATION	ACQUISITIONS AND ACQUISITION-RELATED CONTINGENT CONSIDERATION
	Acquisitions
	On April 22, 2013, Cadence acquired Tensilica, Inc., or Tensilica, a privately held provider of configurable dataplane processing units based in Santa Clara, California. The acquired technology enables Cadence to offer customizable design IP solutions to its customers for applications such as mobile wireless, network infrastructure, audio infotainment and home applications. Total cash consideration for Tensilica, after taking into account adjustments for certain costs and cash held by Tensilica at closing of $26.3 million, was $319.3 million. An additional $5.8 million was placed in escrow, is conditioned upon certain former Tensilica shareholders remaining employees of Cadence and is expensed over the designated retention periods of the former Tensilica shareholders now employed by Cadence. Cadence also assumed certain unvested Tensilica options with a fair value of $15.3 million, of which $0.5 million was allocated to purchase consideration. The remaining $14.8 million of assumed options is expensed over the remaining vesting periods of the awards. The Black-Scholes option-pricing model was used to determine the fair value of the assumed options at the acquisition date. The Black-Scholes option-pricing model incorporates various subjective assumptions including expected volatility, expected term and risk-free interest rates. Cadence will also make payments to certain employees that are conditioned upon continued employment and the achievement of certain performance metrics over a three-year period.
	On May 23, 2013, Cadence acquired Cosmic Circuits Private Limited, or Cosmic, a privately held provider of intellectual property used in system-on-chip design and verification based in Bangalore, India. The acquired technology enables Cadence to offer broader analog and mixed signal IP solutions to its customers. Total cash consideration for Cosmic, after taking into account cash held by Cosmic at closing of $1.7 million, was $59.5 million. Cadence will also make payments to certain employees that are conditioned upon continued employment and the achievement of certain performance metrics over a four-year period. Lip-Bu Tan, Cadence’s president, chief executive officer and director, was also a member of the board of directors of Cosmic. In addition, a trust for the benefit of the children of Mr. Tan owned approximately 8.5% of Cosmic, and Mr. Tan and his wife serve as co-trustees of the trust. Mr. Tan recused himself from the discussions and negotiations between and at Cadence and Cosmic throughout the duration of the transaction, including any discussions and negotiations related to the consideration provided to Cosmic. A financial advisor provided a fairness opinion to Cadence in connection with the transaction, and the Board of Directors of Cadence reviewed the transaction and concluded that it was in the best interests of Cadence to proceed with such transaction.
	During the nine months ended September 28, 2013, Cadence completed another business combination and an asset acquisition for cash and allocated the total purchase consideration of $14.4 million to the assets acquired and liabilities assumed based on their respective fair values on the acquisition dates.
	The following table summarizes the fair value of assets acquired and liabilities assumed as part of the acquisitions completed during the nine months ended September 28, 2013:
		(In thousands)
		Tensilica			Cosmic			Other
	Cash and cash equivalents	$	26,331		$	1,724		$	149
	Trade receivables	4,454			668			—
	Property, plant and equipment	1,938			185			91
	Other assets	46,832			1,681			—
	Acquired intangibles:
	Existing technology	102,000			16,300			2,014
	Agreements and relationships	33,000			5,100			1,667
	Tradenames and trademarks	3,000			—			—
	In-process technology	5,300			4,200			1,200
	Goodwill	176,461			41,911			9,587
	Total assets acquired	$	399,316		$	71,769		$	14,708
	Deferred revenue	(8,100		)	(129		)	—
	Other liabilities	(4,959		)	(1,982		)	(277		)
	Long-term deferred tax liabilities	(40,147		)	(8,428		)	—
	Net assets acquired	$	346,110		$	61,230		$	14,431
	Acquired intangibles with definite lives are amortized on a straight-line basis over the remaining estimated economic life of the underlying products and technologies. The weighted average amortization period for definite-lived intangible assets acquired during the nine months ended September 28, 2013 is approximately 8 years.
	In-process technology consists of projects that had not reached technological feasibility by the date of acquisition and are considered indefinite-lived intangible assets until the completion or abandonment of the project. Upon completion of the project, the assets are amortized over their estimated useful lives. If the project is abandoned rather than completed, the asset is written off. In-process technology is tested for impairment annually or more frequently if events or changes in circumstances indicate that the assets might be impaired.
	The goodwill generated from Cadence's acquisitions during the nine months ended September 28, 2013 is primarily related to expected synergies from combining operations of the acquired companies with Cadence. Cadence expects that approximately $9.6 million of goodwill related to the acquisitions completed during the nine months ended September 28, 2013 will be deductible for tax purposes.
	Results of operations and the estimated fair value of acquired assets and assumed liabilities are recorded in the condensed consolidated financial statements from the date of acquisition. The fair values of acquired intangible assets, including in-process technology, and assumed liabilities were determined using significant inputs that are not observable in the market. For an additional description of these fair value calculations, see Note 7 in the notes to condensed consolidated financial statements.
	The financial information in the table below summarizes the combined results of operations of Cadence and Tensilica, on a pro forma basis, as though the companies had been combined as of the beginning of fiscal 2012. Pro forma results of operations for the other acquisitions completed during the three and nine months ended September 28, 2013 have not been presented because the effects of these acquisitions, individually and in the aggregate, would not have been material to Cadence's financial results. The pro forma financial information for Tensilica is presented for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place on December 31, 2011 or of results that may occur in the future.
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands)
	Total revenue	$	368,694		$	346,999		$	1,101,689		$	1,003,170
	Net income	$	43,679		$	47,180		$	131,753		$	85,280
	Acquisition-related costs were zero and $8.2 million for the three and nine months ended September 28, 2013, respectively, and $0.2 million and $1.3 million for the three and nine months ended September 29, 2012, respectively. These costs consist of professional fees and administrative costs and were expensed as incurred in Cadence's condensed consolidated income statements.
	Acquisition-related Contingent Consideration
	One of the fiscal 2011 acquisitions includes contingent consideration payments based on certain future financial measures associated with the acquired technology. This contingent consideration arrangement requires payments of up to $5.0 million if these measures are met during the three-year period subsequent to October 1, 2011. The fair value of the contingent consideration arrangement recorded on the date of the acquisition was $3.5 million. The fair value of the remaining contingent consideration as of September 28, 2013 was $3.8 million.
	Cadence may be obligated to make cash payments in connection with its business combinations and asset acquisitions completed in prior fiscal years, subject to the satisfaction of certain financial measures. If performance is such that these payments are fully achieved, Cadence may be obligated to pay up to an aggregate of $14.3 million over the next 31 months. Of the $14.3 million, up to $8.7 million would be recorded as operating expenses in the condensed consolidated income statements.

Goodwill_and_Acquired_Intangib

Goodwill and Acquired Intangibles	9 Months Ended
	Sep. 28, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND ACQUIRED INTANGIBLES	GOODWILL AND ACQUIRED INTANGIBLES
	Goodwill
	The changes in the carrying amount of goodwill during the nine months ended September 28, 2013 were as follows:
		Gross Carrying
		Amount
		(In thousands)
	Balance as of December 29, 2012	$	233,266
	Goodwill resulting from acquisitions	227,959
	Effect of foreign currency translation	(4,958		)
	Balance as of September 28, 2013	$	456,267
	Acquired Intangibles, Net
	Acquired intangibles as of September 28, 2013 were as follows, excluding intangibles that were fully amortized as of December 29, 2012:
		Gross Carrying			Accumulated			Acquired
		Amount			Amortization			Intangibles, Net
		(In thousands)
	Existing technology	$	236,774		$	(46,170	)	$	190,604
	Agreements and relationships	171,422			(49,199		)	122,223
	Distribution rights	30,100			(30,100		)	—
	Tradenames, trademarks and patents	9,519			(2,535		)	6,984
	In-process technology	3,996			—			3,996
	Total acquired intangibles	$	451,811		$	(128,004	)	$	323,807
	In-process technology as of September 28, 2013 consists of projects acquired during the nine months ended September 28, 2013, and if completed, will contribute to Cadence's ability to offer additional IP solutions to its customers. These projects are expected to be complete in 6 to 12 months. During the nine months ended September 28, 2013, Cadence completed certain projects previously included in in-process technology and transferred approximately $5.5 million to existing technology.
	Acquired intangibles as of December 29, 2012 were as follows, excluding intangibles that were fully amortized as of December 31, 2011:
		Gross Carrying			Accumulated			Acquired
		Amount			Amortization			Intangibles, Net
		(In thousands)
	Existing technology	$	112,940		$	(30,171	)	$	82,769
	Agreements and relationships	133,764			(37,769		)	95,995
	Distribution rights	30,100			(28,595		)	1,505
	Tradenames, trademarks and patents	12,485			(7,816		)	4,669
	Total acquired intangibles	$	289,289		$	(104,351	)	$	184,938
	Amortization expense for intangible assets from existing technology and maintenance agreements is included in cost of product and maintenance. Amortization of acquired intangibles for the three and nine months ended September 28, 2013 and September 29, 2012 was as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,		September 29,
		2013			2012			2013		2012
		(In thousands)
	Cost of product and maintenance	$	7,191		$	3,874		$	16,758	$	9,664
	Amortization of acquired intangibles	5,141			3,876			14,259		11,305
	Total amortization of acquired intangibles	$	12,332		$	7,750		$	31,017	$	20,969
	Estimated amortization expense for the following five fiscal years and thereafter is as follows:
		(In thousands)
	2013 – remaining period	$	12,446
	2014	49,929
	2015	49,378
	2016	43,666
	2017	40,060
	Thereafter	128,328
	Total estimated amortization expense	$	323,807

Income_Taxes_Income_Taxes

Income Taxes Income Taxes	9 Months Ended
	Sep. 28, 2013
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	During the nine months ended September 28, 2013, Cadence recognized a provision for income taxes of approximately $3.0 million primarily because of:
	•	Federal, state and foreign tax expense on anticipated fiscal 2013 income; and
	•	Tax expense related to integrating the acquisitions;
	which were partially offset by:
	•	A tax benefit of $33.7 million from the release of an uncertain tax position recorded in a previous business combination and the release of related interest and penalties; and
	•	A tax benefit of $5.9 million for the fiscal 2012 federal research tax credit that was retroactively enacted.
	Unrecognized Tax Benefits
	During the nine months ended September 28, 2013, Cadence determined that the State of California Franchise Tax Board examination of the 2004 through 2006 tax years was effectively settled and, separately, released an unrecognized tax benefit recorded in a prior business combination.
	The changes in Cadence's gross amount of unrecognized tax benefits during the nine months ended September 28, 2013 are as follows:
		Unrecognized tax benefits
		(In thousands)
	Unrecognized tax benefits as of December 29, 2012	$	92,378
	Gross amount of the increases in unrecognized tax benefits of tax positions taken during a prior year	6,476
	Gross amount of the increases in unrecognized tax benefits as a result of tax positions taken during the current year	13,088
	Amount of decreases in unrecognized tax benefits relating to settlements with taxing authorities, including the utilization of tax attributes	(13,821		)
	Reductions to unrecognized tax benefits resulting from the lapse of the applicable statute of limitations	(12,044		)
	Effect of foreign currency translation	497
	Unrecognized tax benefits as of September 28, 2013	$	86,574
	Total amounts of unrecognized tax benefits that, if upon resolution of the uncertain tax positions would reduce Cadence's effective tax rate as of September 28, 2013	$	49,914
	The total amounts of interest and penalties recognized in the condensed consolidated income statements as provision (benefit) for income taxes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands)
	Interest	$	728		$	820		$	(12,731	)	$	2,584
	Penalties	(708		)	(36		)	(7,666		)	(1,012		)
	The total amounts of gross accrued interest and penalties recognized in the condensed consolidated balance sheets as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Interest	$	52		$	24,427
	Penalties	1,255			8,953

Receivables_and_Allowances_for

Receivables and Allowances for Doubtful Accounts	9 Months Ended
	Sep. 28, 2013
Receivables [Abstract]
RECEIVABLES AND ALLOWANCES FOR DOUBTFUL ACCOUNTS	RECEIVABLES AND ALLOWANCES FOR DOUBTFUL ACCOUNTS
	Cadence’s current and long-term receivables balances as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Accounts receivable	$	61,906		$	67,259
	Installment contract receivables, short-term	40,134			30,647
	Long-term receivables	3,994			7,559
	Total receivables	$	106,034		$	105,465
	Less allowance for doubtful accounts	(144		)	(85		)
	Total receivables, net	$	105,890		$	105,380
	Cadence’s customers are primarily concentrated within the semiconductor, electronics systems and consumer electronics industries. As of September 28, 2013, one customer accounted for approximately 13% of Cadence’s total receivables. As of December 29, 2012, no single customer accounted for 10% of Cadence's total receivables. As of September 28, 2013, approximately 53% of Cadence’s total receivables were attributable to the ten customers with the largest balances of total receivables. As of December 29, 2012, approximately 47% of Cadence’s total receivables were attributable to the ten customers with the largest balances of total receivables.

Fair_Value

Fair Value	9 Months Ended
	Sep. 28, 2013
Fair Value Disclosures [Abstract]
FAIR VALUE	FAIR VALUE
	Inputs to valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Cadence’s market assumptions. These two types of inputs have created the following fair value hierarchy:
	•	Level 1 – Quoted prices for identical instruments in active markets;
	•	Level 2 – Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and
	•	Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.
	This hierarchy requires Cadence to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. Cadence recognizes transfers between levels of the hierarchy based on the fair values of the respective financial instruments at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the three and nine months ended September 28, 2013.
	On a quarterly basis, Cadence measures at fair value certain financial assets and liabilities. The fair value of financial assets and liabilities was determined using the following levels of inputs as of September 28, 2013 and December 29, 2012:
		Fair Value Measurements as of September 28, 2013:
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Assets
	Cash equivalents:
	Money market funds	$	475,563		$	475,563	$	—	$	—
	Bank certificates of deposit	1,000			—		1,000		—
	Short-term investments:
	Corporate debt securities	36,878			—		36,878		—
	Bank certificates of deposit	18,313			—		18,313		—
	United States Treasury securities	24,738			24,738		—		—
	United States government agency securities	11,227			11,227		—		—
	Commercial paper	2,797			—		2,797		—
	Marketable equity securities	2,066			2,066		—		—
	Trading securities held in Non-Qualified Deferred Compensation, or NQDC, trust	22,339			22,339		—		—
	2015 Notes Hedges	292,511			—		292,511		—
	Foreign currency exchange contracts	1,662			—		1,662		—
	Total Assets	$	889,094		$	535,933	$	353,161	$	—
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Liabilities
	Acquisition-related contingent consideration	$	3,835		$	—	$	—	$	3,835
	2015 Notes Embedded Conversion Derivative	292,511			—		292,511		—
	Total Liabilities	$	296,346		$	—	$	292,511	$	3,835
		Fair Value Measurements as of December 29, 2012:
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Assets
	Cash equivalents:
	Money market funds	$	566,334		$	566,334	$	—	$	—
	Short-term investments:
	Corporate debt securities	31,359			—		31,359		—
	Bank certificates of deposit	27,826			—		27,826		—
	United States Treasury securities	23,239			23,239		—		—
	United States government agency securities	10,258			10,258		—		—
	Commercial paper	5,783			—		5,783		—
	Marketable equity securities	2,239			2,239		—		—
	Trading securities held in NQDC trust	24,329			24,329		—		—
	2015 Notes Hedges	303,154			—		303,154		—
	Foreign currency exchange contracts	1,737			—		1,737		—
	Total Assets	$	996,258		$	626,399	$	369,859	$	—
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Liabilities
	Acquisition-related contingent consideration	$	4,218		$	—	$	—	$	4,218
	2015 Notes Embedded Conversion Derivative	303,154			—		303,154		—
	Total Liabilities	$	307,372		$	—	$	303,154	$	4,218
	Level 1 Measurements
	Cadence’s cash equivalents held in money market funds, available-for-sale United States Treasury securities, United States government agency securities, marketable equity securities and the trading securities held in Cadence’s NQDC trust are measured at fair value using level 1 inputs.
	Level 2 Measurements
	The 2015 Notes Hedges and the 2015 Notes Embedded Conversion Derivative are measured at fair value using level 1 and level 2 inputs. These instruments are not actively traded and are valued using an option pricing model that uses observable market data for all inputs, such as implied volatility of Cadence’s common stock, risk-free interest rate and other factors.
	Cadence’s available-for-sale corporate debt securities, bank certificates of deposit and commercial paper are measured at fair value using level 2 inputs. Cadence obtains the fair values of its level 2 available-for-sale securities from a professional pricing service and validates the fair values by assessing the pricing methods and inputs and by comparing the fair values to another independent source.
	The fair values of Cadence’s 2013 Notes and 2015 Notes, which differ from their carrying values, are influenced by interest rates and Cadence’s stock price and stock price volatility and are determined by prices for the 2013 Notes and 2015 Notes observed in market trading, which are level 2 inputs.
	Cadence’s foreign currency exchange contracts are measured at fair value using observable foreign currency exchange rates.
	Level 3 Measurements
	The liabilities included in level 3 represent the fair value of contingent consideration associated with certain of Cadence’s 2011 and 2010 acquisitions. Cadence makes estimates regarding the fair value of contingent consideration liabilities on the acquisition date and at the end of each reporting period until the contingency is resolved. The fair value of these arrangements is determined by calculating the net present value of the expected payments using significant inputs that are not observable in the market, including revenue projections and discount rates consistent with the level of risk of achievement. The fair value of these contingent consideration arrangements is affected most significantly by the changes in the revenue projections, but is also impacted by the discount rate used to adjust the outcomes to their present values. If the revenue projections increase or decrease, the fair value of the contingent consideration will increase or decrease accordingly, in amounts that will vary based on the timing of the projected revenues, the timing of the expected payments and the discount rate used to calculate the present value of the expected payments. Cadence used discount rates ranging from 11% to 16% to value its contingent consideration liabilities as of September 28, 2013 and December 29, 2012. Cadence believes that its estimates and assumptions are reasonable, but significant judgment is involved.
	Changes in the fair value of contingent consideration liabilities subsequent to the acquisition are recorded in general and administrative expense in the condensed consolidated income statements.
The following table summarizes the level 3 activity for the nine months ended September 28, 2013:
	(In thousands)
Balance as of December 29, 2012	$	4,218
Payments	(835		)
Adjustments	452
Balance as of September 28, 2013	$	3,835
Cadence acquired intangible assets, including in-process technology, of $173.8 million in connection with its acquisitions during the nine months ended September 28, 2013. The fair value of the intangible assets acquired was determined using the income approach and using level 3 inputs. Key assumptions include the level and timing of expected future cash flows, conditions and demands specific to IP solutions, discount rates consistent with the level of risk and the economy in general. The fair value of these intangible assets was affected most significantly by the projected income associated with the intangible assets and the anticipated timing of the projected income, but was also impacted by the discount rate used to adjust the outcomes to their present values. If the income projections had increased or decreased, the fair value of the intangible assets would have increased or decreased accordingly in amounts that would have varied based on the anticipated timing of the projected income and the discount rate used to calculate the present value of the expected income. Cadence used discount rates ranging from 10% to 15% to value the intangible assets acquired during the nine months ended September 29, 2013.
As part of its acquisitions, Cadence also assumed obligations related to deferred revenue of $8.2 million, which was estimated using the cost build-up approach. The cost build-up approach determines fair value using estimates of the costs required to provide the contracted deliverables plus an assumed profit between 10% and 25%. The total costs including the assumed profit were adjusted to present value using a discount rate of approximately 3%. The resulting fair value approximates the amount that Cadence would be required to pay a third party to assume the obligation. The fair value of the deferred revenue obligation was affected most significantly by the estimated costs required to support the obligation, but was also affected by the assumed profit and the discount rate.
Cadence believes that its estimates and assumptions related to the fair value of its acquired intangible assets and deferred revenue obligations are reasonable, but significant judgment is involved.

Cash_Cash_Equivalents_and_Inve

Cash, Cash Equivalents and Investments	9 Months Ended
	Sep. 28, 2013
Cash, Cash Equivalents and Investments [Abstract]
CASH, CASH EQUIVALENTS AND INVESTMENTS	CASH, CASH EQUIVALENTS AND INVESTMENTS
	Cadence’s cash, cash equivalents and short-term investments at fair value as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Cash and cash equivalents	$	620,403	$	726,357
	Short-term investments	96,019		100,704
	Cash, cash equivalents and short-term investments	$	716,422	$	827,061
	Cash and Cash Equivalents
	Cadence considers all highly liquid investments with original maturities of three months or less on the date of purchase to be cash equivalents. The amortized cost of Cadence’s cash equivalents approximates fair value. The following table summarizes Cadence’s cash and cash equivalents at fair value as of September 28, 2013 and December 29, 2012:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Cash and interest bearing deposits	$	143,840	$	160,023
	Money market funds	475,563		566,334
	Bank certificates of deposit	1,000		—
	Total cash and cash equivalents	$	620,403	$	726,357
	Short-Term Investments
	The following tables summarize Cadence’s short-term investments as of September 28, 2013 and December 29, 2012:
		As of September 28, 2013
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
		(In thousands)
	Corporate debt securities	$	36,859	$	33	$	(14	)	$	36,878
	Bank certificates of deposit	18,300		13		—			18,313
	United States Treasury securities	24,705		34		(1		)	24,738
	United States government agency securities	11,215		13		(1		)	11,227
	Commercial paper	2,794		3		—			2,797
	Marketable debt securities	93,873		96		(16		)	93,953
	Marketable equity securities	1,817		249		—			2,066
	Total short-term investments	$	95,690	$	345	$	(16	)	$	96,019
		As of December 29, 2012
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
		(In thousands)
	Corporate debt securities	$	31,313	$	57	$	(11	)	$	31,359
	Bank certificates of deposit	27,805		21		—			27,826
	United States Treasury securities	23,213		26		—			23,239
	United States government agency securities	10,245		13		—			10,258
	Commercial paper	5,777		6		—			5,783
	Marketable debt securities	98,353		123		(11		)	98,465
	Marketable equity securities	1,817		422		—			2,239
	Total short-term investments	$	100,170	$	545	$	(11	)	$	100,704
	As of September 28, 2013, no securities held by Cadence have been in an unrealized loss position for greater than six months.
	The amortized cost and estimated fair value of marketable debt securities included in short-term investments as of September 28, 2013, by contractual maturity, are shown in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without penalties.
		Amortized		Fair
		Cost		Value
		(In thousands)
	Due in less than one year	$	48,949	$	48,983
	Due in one to three years	44,924		44,970
	Total marketable debt securities included in short-term investments	$	93,873	$	93,953
	Net realized gains from the sale of marketable debt and equity securities during the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended				Nine Months Ended
		September 28,		September 29,		September 28,			September 29,
		2013		2012		2013			2012
		(In thousands)				(In thousands)
	Gains on sale of marketable debt and equity securities, net	$	1,363	$	8	$	1,339		$	123
	Non-Marketable Investments
	Cadence’s non-marketable investments generally consist of voting preferred stock or convertible debt of privately held companies and are included in other assets on Cadence’s condensed consolidated balance sheets. If Cadence determines that it has the ability to exercise significant influence over the issuer, which may include considering whether the investments are in-substance common stock, the investment is accounted for using the equity method.
	Cadence’s non-marketable investments as of September 28, 2013 and December 29, 2012 were as follows:
	As of
	September 28,		December 29,
	2013		2012
	(In thousands)
Cost method	$	3,038	$	3,038
Equity method	3,648		4,249
Total non-marketable investments	$	6,686	$	7,287
Net realized gains on the sale of non-marketable investments during the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
	Three Months Ended				Nine Months Ended
	September 28,		September 29,		September 28,			September 29,
	2013		2012		2013			2012
	(In thousands)				(In thousands)
Gains on sale of non-marketable investments, net	$	6	$	—	$	1,196		$	—

Net_Income_per_Share

Net Income per Share	9 Months Ended
	Sep. 28, 2013
Earnings Per Share [Abstract]
NET INCOME PER SHARE	NET INCOME PER SHARE
	Basic net income per share is computed by dividing net income during the period by the weighted average number of shares of common stock outstanding during that period, less unvested restricted stock awards. Diluted net income per share is impacted by equity instruments considered to be potential common shares, if dilutive, computed using the treasury stock method of accounting.
	The calculations for basic and diluted net income per share for the three and nine months ended September 28, 2013 and September 29, 2012 are as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,		September 29,
		2013			2012			2013		2012
		(In thousands, except per share amounts)
	Net income	$	38,500		$	58,584		$	126,538	$	126,074
	Weighted average common shares used to calculate basic net income per share	278,977			271,350			277,034		269,643
	2023 Notes	9			11			11		11
	2015 Warrants	11,587			6,286			11,042		3,148
	Share-based awards	6,385			5,681			6,444		5,958
	Weighted average common shares used to calculate diluted net income per share	296,958			283,328			294,531		278,760
	Net income per share - basic	$	0.14		$	0.22		$	0.46	$	0.47
	Net income per share - diluted	$	0.13		$	0.21		$	0.43	$	0.45
	The following table presents shares of Cadence’s common stock outstanding for the three and nine months ended September 28, 2013, and September 29, 2012, that were excluded from the computation of diluted net income per share because the effect of including these shares in the computation of diluted net income per share would have been anti-dilutive:
		Three Months Ended					Nine Months Ended
		September 28,		September 29,			September 28,		September 29,
		2013		2012			2013		2012
		(In thousands)
	2013 Warrants	6,830		6,830			6,830		6,830
	Options to purchase shares of common stock	5,639		10,003			6,048		12,767
	Non-vested shares of restricted stock	3,280		10			1,099		82
	Total potential common shares excluded	15,749		16,843			13,977		19,679

Other_Comprehensive_Income

Other Comprehensive Income	9 Months Ended
	Sep. 28, 2013
Other Comprehensive Income (Loss), Net of Tax [Abstract]
OTHER COMPREHENSIVE INCOME	OTHER COMPREHENSIVE INCOME
	Cadence’s other comprehensive income is comprised of foreign currency translation gains and losses, changes in defined benefit plan liabilities, and changes in unrealized holding gains and losses on available-for-sale securities net of reclassifications for realized gains and losses as presented in Cadence’s condensed consolidated statements of comprehensive income.
	Accumulated other comprehensive income was comprised of the following as of September 28, 2013, and December 29, 2012:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Foreign currency translation gain	$	25,345		$	48,653
	Changes in defined benefit plan liabilities	(4,781		)	(5,229		)
	Unrealized holding gains on available-for-sale securities	320			526
	Total accumulated other comprehensive income	$	20,884		$	43,950
	For the three and nine months ended September 28, 2013 and September 29, 2012 there were no significant amounts reclassified from accumulated other comprehensive income to net income.

Contingencies

Contingencies	9 Months Ended
	Sep. 28, 2013
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	CONTINGENCIES
	Legal Proceedings
	From time to time, Cadence is involved in various disputes and litigation that arise in the ordinary course of business. These include disputes and lawsuits related to intellectual property, indemnification obligations, mergers and acquisitions, licensing, contracts, distribution arrangements and employee relations matters. At least quarterly, Cadence reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and the amount or the range of loss can be estimated, Cadence accrues a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, accruals are based on Cadence’s judgments using the best information available at the time. As additional information becomes available, Cadence reassesses the potential liability related to pending claims and litigation matters and may revise estimates.
	Other Contingencies
	Cadence provides its customers with a warranty on sales of hardware products, generally for a 90-day period. Cadence did not incur any significant costs related to warranty obligations during the three and nine months ended September 28, 2013 or September 29, 2012.
	Cadence’s product license and services agreements typically include a limited indemnification provision for claims from third parties relating to Cadence’s intellectual property. If the potential loss from any indemnification claim is considered probable and the amount or the range of loss can be estimated, Cadence accrues a liability for the estimated loss. The indemnification is generally limited to the amount paid by the customer. Cadence did not incur any significant losses from indemnification claims during the three and nine months ended September 28, 2013 or September 29, 2012.

Other_Income_Net

Other Income, Net	9 Months Ended
	Sep. 28, 2013
Other Income and Expenses [Abstract]
OTHER INCOME, NET	OTHER INCOME, NET
	Cadence’s other income, net for the three and nine months ended September 28, 2013 and September 29, 2012 was as follows:
		Three Months Ended					Nine Months Ended
		September 28,		September 29,			September 28,			September 29,
		2013		2012			2013			2012
		(In thousands)
	Interest income	$	366	$	399		$	1,275		$	1,024
	Gains on sale of marketable debt and equity securities, net	1,363		8			1,339			123
	Gains on sale of non-marketable investments, net	6		—			1,196			—
	Gains (losses) on securities in NQDC trust	206		(839		)	2,057			3,237
	Gains on foreign exchange	489		1,376			1,476			2,546
	Write-down of non-marketable investments	—		(1,081		)	(464		)	(1,103		)
	Other income (expense), net	105		6			(151		)	145
	Total other income (expense), net	$	2,535	$	(131	)	$	6,728		$	5,972

Segment_Reporting

Segment Reporting	9 Months Ended
	Sep. 28, 2013
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING
	Segment reporting is based on the “management approach,” following the method that management organizes the company’s reportable segments for which separate financial information is made available to, and evaluated regularly by, the chief operating decision maker in allocating resources and in assessing performance. Cadence’s chief operating decision maker is its President and Chief Executive Officer, or CEO, who reviews Cadence’s consolidated results as one reportable segment. In making operating decisions, the CEO primarily considers consolidated financial information, accompanied by disaggregated information about revenues by geographic region.
	Outside the United States, Cadence markets and supports its products and services primarily through its subsidiaries. Revenue is attributed to geography based upon the country in which the product is used or services are delivered. Long-lived assets are attributed to geography based on the country where the assets are located.
	The following table presents a summary of revenue by geography for the three and nine months ended September 28, 2013 and September 29, 2012:
		Three Months Ended				Nine Months Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
		(In thousands)
	Americas:
	United States	$	168,125	$	141,509	$	476,525	$	414,888
	Other Americas	7,212		4,733		17,393		18,659
	Total Americas	175,337		146,242		493,918		433,547
	Europe, Middle East and Africa	72,376		66,392		229,053		191,097
	Japan	45,853		58,757		144,794		168,856
	Asia	73,081		67,142		215,629		187,339
	Total	$	366,647	$	338,533	$	1,083,394	$	980,839
	The following table presents a summary of long-lived assets by geography as of September 28, 2013 and December 29, 2012:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Americas:
	United States	$	209,783	$	214,711
	Other Americas	330		185
	Total Americas	210,113		214,896
	Europe, Middle East and Africa	6,354		5,410
	Japan	974		1,649
	Asia	24,524		22,484
	Total	$	241,965	$	244,439

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 28, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Preparation of the condensed consolidated financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
In-Process Technology	In-process technology consists of projects that had not reached technological feasibility by the date of acquisition and are considered indefinite-lived intangible assets until the completion or abandonment of the project. Upon completion of the project, the assets are amortized over their estimated useful lives. If the project is abandoned rather than completed, the asset is written off. In-process technology is tested for impairment annually or more frequently if events or changes in circumstances indicate that the assets might be impaired.
Fair Value of Financial Instruments	Inputs to valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Cadence’s market assumptions. These two types of inputs have created the following fair value hierarchy:
	•	Level 1 – Quoted prices for identical instruments in active markets;
	•	Level 2 – Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and
	•	Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.
	This hierarchy requires Cadence to minimize the use of unobservable inputs and to use observable market data, if available, when determining fair value. Cadence recognizes transfers between levels of the hierarchy based on the fair values of the respective financial instruments at the end of the reporting period in which the transfer occurred. There were no transfers between levels of the fair value hierarchy during the three and nine months ended September 28, 2013.
Contingencies	At least quarterly, Cadence reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and the amount or the range of loss can be estimated, Cadence accrues a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, accruals are based on Cadence’s judgments using the best information available at the time. As additional information becomes available, Cadence reassesses the potential liability related to pending claims and litigation matters and may revise estimates.
Non-Marketable Investments	Cadence’s non-marketable investments generally consist of voting preferred stock or convertible debt of privately held companies and are included in other assets on Cadence’s condensed consolidated balance sheets. If Cadence determines that it has the ability to exercise significant influence over the issuer, which may include considering whether the investments are in-substance common stock, the investment is accounted for using the equity method.

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 28, 2013
Debt Disclosure [Abstract]
Summary of debt outstanding	Cadence’s outstanding debt as of September 28, 2013 and December 29, 2012 was as follows:
		28-Sep-13									December 29, 2012
		(In thousands)
		Principal			Unamortized Discount			Carrying Value			Principal			Unamortized Discount			Carrying Value
	2015 Notes	$	350,000		$	(29,275	)	$	320,725		$	350,000		$	(41,181	)	$	308,819
	2013 Notes	144,461			(1,449		)	143,012			144,461			(6,447		)	138,014
	2023 Notes	100			—			100			178			—			178
	Revolving credit facility	50,000			—			50,000			—			—			—
	Total outstanding debt	$	544,561		$	(30,724	)	$	513,837		$	494,639		$	(47,628	)	$	447,011
Summary of key terms of 2015 notes and 2013 notes	A summary of key terms of the 2015 Notes is as follows:
			2015 Notes
			(In thousands, except percentages and per share amounts)
	Outstanding principal maturity value – at September 28, 2013		$350,000
	Contractual interest rate		2.63%
	Contractual maturity date		June 1, 2015
	Initial conversion rate		132.5205 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $7.55 per share of Cadence common stock.
	Conversion feature (in addition to principal amount payable in cash)		Cash to the extent Cadence’s stock price exceeds approximately $7.55 per share, calculated based on the applicable conversion rate multiplied by the volume weighted average price of Cadence common stock over a specified period.
	Early conversion conditions (or the Early Conversion Conditions)		• Closing stock price greater than $9.81 for at least 20 of the last 30 trading days in a fiscal quarter (convertible only for subsequent quarter);
			• Specified corporate transactions; or
			• Note trading price falls below a calculated minimum.
	Conversion immediately preceding maturity		From March 1, 2015 until the second trading day immediately preceding the maturity date, holders may convert their 2015 Notes at any time into cash as described above under “Conversion feature.”
	Redemption at Cadence’s option prior to maturity		None.
	Fundamental change put right		Upon certain fundamental corporate changes prior to maturity, the 2015 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest.
	Make-whole premium		Upon certain fundamental changes prior to maturity, if Cadence’s stock price were between $6.16 and $40.00 per share at that time, the 2015 Note holders would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
	Financial covenants		None.
	A summary of key terms of the 2013 Notes is as follows:
			2013 Notes
			(In thousands, except percentages and per share amounts)
	Principal maturity value – at issuance		$250,000
	Outstanding principal maturity value – at September 28, 2013		$144,461
	Contractual interest rate		1.50%
	Contractual maturity date		15-Dec-13
	Equity component - included in common stock - at September 28, 2013 and December 29, 2012		$63,027
	Initial conversion rate		47.2813 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $21.15 per share of Cadence common stock.
	Conversion feature (in addition to principal amount payable in cash)		Shares to the extent Cadence’s stock price exceeds $21.15 per share, calculated based on the applicable conversion rate multiplied by the volume weighted average price of Cadence common stock over a specified period.
	Early conversion conditions (or the Early Conversion Conditions)		•  Closing stock price greater than $27.50 for at least 20 of the last 30 trading days in a calendar quarter (convertible only for subsequent quarter);
			•  Specified corporate transactions; or
			•  Note trading price falls below calculated minimum.
	Conversion immediately preceding maturity		From November 1, 2013, and until the trading day immediately preceding the maturity date, holders may convert their 2013 Notes at any time into cash and Cadence shares as described above under “Conversion feature.”
	Redemption at Cadence’s option prior to maturity		None.
	Fundamental change put right		Upon a fundamental change prior to maturity, the 2013 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest.
	Make-whole premium		Upon certain fundamental changes, prior to maturity, if Cadence’s stock price were between $18.00 and $60.00 per share at that time, the 2013 Note holders would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
	Financial covenants		None.
Effective interest rate and components of interest expense of 2015 notes	The effective interest rate and components of interest expense of the 2015 Notes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands, except percentages)
	Effective interest rate	8.1		%	8.1		%	8.1		%	8.1		%
	Contractual interest expense	$	2,289		$	2,289		$	6,867		$	6,867
	Amortization of debt discount	$	4,045		$	3,737		$	11,906		$	10,968
Effective interest rate and components of interest expense of 2013 notes	The effective interest rate and components of interest expense of the 2013 Notes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands, except percentages)
	Effective interest rate	6.4		%	6.4		%	6.4		%	6.4		%
	Contractual interest expense	$	540		$	540		$	1,619		$	1,619
	Amortization of debt discount	$	1,691		$	1,588		$	4,998		$	4,674

Acquisitions_and_AcquisitionRe1

Acquisitions and Acquisition-Related Contingent Consideration Acquisitions and Acquisition Related Contingent Consideration (Tables)	9 Months Ended
	Sep. 28, 2013
Business Combinations [Abstract]
Schedule of identified assets acquired and liabilities assumed	The following table summarizes the fair value of assets acquired and liabilities assumed as part of the acquisitions completed during the nine months ended September 28, 2013:
		(In thousands)
		Tensilica			Cosmic			Other
	Cash and cash equivalents	$	26,331		$	1,724		$	149
	Trade receivables	4,454			668			—
	Property, plant and equipment	1,938			185			91
	Other assets	46,832			1,681			—
	Acquired intangibles:
	Existing technology	102,000			16,300			2,014
	Agreements and relationships	33,000			5,100			1,667
	Tradenames and trademarks	3,000			—			—
	In-process technology	5,300			4,200			1,200
	Goodwill	176,461			41,911			9,587
	Total assets acquired	$	399,316		$	71,769		$	14,708
	Deferred revenue	(8,100		)	(129		)	—
	Other liabilities	(4,959		)	(1,982		)	(277		)
	Long-term deferred tax liabilities	(40,147		)	(8,428		)	—
	Net assets acquired	$	346,110		$	61,230		$	14,431
Pro forma financial information	The financial information in the table below summarizes the combined results of operations of Cadence and Tensilica, on a pro forma basis, as though the companies had been combined as of the beginning of fiscal 2012. Pro forma results of operations for the other acquisitions completed during the three and nine months ended September 28, 2013 have not been presented because the effects of these acquisitions, individually and in the aggregate, would not have been material to Cadence's financial results. The pro forma financial information for Tensilica is presented for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place on December 31, 2011 or of results that may occur in the future.
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands)
	Total revenue	$	368,694		$	346,999		$	1,101,689		$	1,003,170
	Net income	$	43,679		$	47,180		$	131,753		$	85,280

Goodwill_and_Acquired_Intangib1

Goodwill and Acquired Intangibles (Tables)	9 Months Ended
	Sep. 28, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying amount of goodwill	The changes in the carrying amount of goodwill during the nine months ended September 28, 2013 were as follows:
		Gross Carrying
		Amount
		(In thousands)
	Balance as of December 29, 2012	$	233,266
	Goodwill resulting from acquisitions	227,959
	Effect of foreign currency translation	(4,958		)
	Balance as of September 28, 2013	$	456,267
Acquired intangibles with finite and indefinite lives, excluding intangibles fully amortized at end of prior fiscal year	Acquired intangibles as of December 29, 2012 were as follows, excluding intangibles that were fully amortized as of December 31, 2011:
		Gross Carrying			Accumulated			Acquired
		Amount			Amortization			Intangibles, Net
		(In thousands)
	Existing technology	$	112,940		$	(30,171	)	$	82,769
	Agreements and relationships	133,764			(37,769		)	95,995
	Distribution rights	30,100			(28,595		)	1,505
	Tradenames, trademarks and patents	12,485			(7,816		)	4,669
	Total acquired intangibles	$	289,289		$	(104,351	)	$	184,938
	Acquired intangibles as of September 28, 2013 were as follows, excluding intangibles that were fully amortized as of December 29, 2012:
		Gross Carrying			Accumulated			Acquired
		Amount			Amortization			Intangibles, Net
		(In thousands)
	Existing technology	$	236,774		$	(46,170	)	$	190,604
	Agreements and relationships	171,422			(49,199		)	122,223
	Distribution rights	30,100			(30,100		)	—
	Tradenames, trademarks and patents	9,519			(2,535		)	6,984
	In-process technology	3,996			—			3,996
	Total acquired intangibles	$	451,811		$	(128,004	)	$	323,807
Amortization of acquired intangibles	Amortization of acquired intangibles for the three and nine months ended September 28, 2013 and September 29, 2012 was as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,		September 29,
		2013			2012			2013		2012
		(In thousands)
	Cost of product and maintenance	$	7,191		$	3,874		$	16,758	$	9,664
	Amortization of acquired intangibles	5,141			3,876			14,259		11,305
	Total amortization of acquired intangibles	$	12,332		$	7,750		$	31,017	$	20,969
Estimated amortization expense	Estimated amortization expense for the following five fiscal years and thereafter is as follows:
		(In thousands)
	2013 – remaining period	$	12,446
	2014	49,929
	2015	49,378
	2016	43,666
	2017	40,060
	Thereafter	128,328
	Total estimated amortization expense	$	323,807

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	9 Months Ended
	Sep. 28, 2013
Unrecognized Tax Benefits [Abstract]
Unrecognized tax benefits rollforward	The changes in Cadence's gross amount of unrecognized tax benefits during the nine months ended September 28, 2013 are as follows:
		Unrecognized tax benefits
		(In thousands)
	Unrecognized tax benefits as of December 29, 2012	$	92,378
	Gross amount of the increases in unrecognized tax benefits of tax positions taken during a prior year	6,476
	Gross amount of the increases in unrecognized tax benefits as a result of tax positions taken during the current year	13,088
	Amount of decreases in unrecognized tax benefits relating to settlements with taxing authorities, including the utilization of tax attributes	(13,821		)
	Reductions to unrecognized tax benefits resulting from the lapse of the applicable statute of limitations	(12,044		)
	Effect of foreign currency translation	497
	Unrecognized tax benefits as of September 28, 2013	$	86,574
	Total amounts of unrecognized tax benefits that, if upon resolution of the uncertain tax positions would reduce Cadence's effective tax rate as of September 28, 2013	$	49,914
Interest and penalties recognized in the condensed consolidated income statements	The total amounts of interest and penalties recognized in the condensed consolidated income statements as provision (benefit) for income taxes for the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,			September 29,
		2013			2012			2013			2012
		(In thousands)
	Interest	$	728		$	820		$	(12,731	)	$	2,584
	Penalties	(708		)	(36		)	(7,666		)	(1,012		)
Interest and penalties recognized in the condensed consolidated balance sheets	The total amounts of gross accrued interest and penalties recognized in the condensed consolidated balance sheets as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Interest	$	52		$	24,427
	Penalties	1,255			8,953

Receivables_and_Allowances_for1

Receivables and Allowances for Doubtful Accounts (Tables)	9 Months Ended
	Sep. 28, 2013
Receivables [Abstract]
Current and long-term accounts receivable balances	Cadence’s current and long-term receivables balances as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Accounts receivable	$	61,906		$	67,259
	Installment contract receivables, short-term	40,134			30,647
	Long-term receivables	3,994			7,559
	Total receivables	$	106,034		$	105,465
	Less allowance for doubtful accounts	(144		)	(85		)
	Total receivables, net	$	105,890		$	105,380

Fair_Value_Tables

Fair Value (Tables)	9 Months Ended
	Sep. 28, 2013
Fair Value Disclosures [Abstract]
Fair value of financial assets and liabilities	On a quarterly basis, Cadence measures at fair value certain financial assets and liabilities. The fair value of financial assets and liabilities was determined using the following levels of inputs as of September 28, 2013 and December 29, 2012:
		Fair Value Measurements as of September 28, 2013:
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Assets
	Cash equivalents:
	Money market funds	$	475,563		$	475,563	$	—	$	—
	Bank certificates of deposit	1,000			—		1,000		—
	Short-term investments:
	Corporate debt securities	36,878			—		36,878		—
	Bank certificates of deposit	18,313			—		18,313		—
	United States Treasury securities	24,738			24,738		—		—
	United States government agency securities	11,227			11,227		—		—
	Commercial paper	2,797			—		2,797		—
	Marketable equity securities	2,066			2,066		—		—
	Trading securities held in Non-Qualified Deferred Compensation, or NQDC, trust	22,339			22,339		—		—
	2015 Notes Hedges	292,511			—		292,511		—
	Foreign currency exchange contracts	1,662			—		1,662		—
	Total Assets	$	889,094		$	535,933	$	353,161	$	—
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Liabilities
	Acquisition-related contingent consideration	$	3,835		$	—	$	—	$	3,835
	2015 Notes Embedded Conversion Derivative	292,511			—		292,511		—
	Total Liabilities	$	296,346		$	—	$	292,511	$	3,835
		Fair Value Measurements as of December 29, 2012:
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Assets
	Cash equivalents:
	Money market funds	$	566,334		$	566,334	$	—	$	—
	Short-term investments:
	Corporate debt securities	31,359			—		31,359		—
	Bank certificates of deposit	27,826			—		27,826		—
	United States Treasury securities	23,239			23,239		—		—
	United States government agency securities	10,258			10,258		—		—
	Commercial paper	5,783			—		5,783		—
	Marketable equity securities	2,239			2,239		—		—
	Trading securities held in NQDC trust	24,329			24,329		—		—
	2015 Notes Hedges	303,154			—		303,154		—
	Foreign currency exchange contracts	1,737			—		1,737		—
	Total Assets	$	996,258		$	626,399	$	369,859	$	—
		Total			Level 1		Level 2		Level 3
		(In thousands)
	Liabilities
	Acquisition-related contingent consideration	$	4,218		$	—	$	—	$	4,218
	2015 Notes Embedded Conversion Derivative	303,154			—		303,154		—
	Total Liabilities	$	307,372		$	—	$	303,154	$	4,218
Liabilities included in level 3 representing fair value of contingent consideration associated with acquisitions	The following table summarizes the level 3 activity for the nine months ended September 28, 2013:
		(In thousands)
	Balance as of December 29, 2012	$	4,218
	Payments	(835		)
	Adjustments	452
	Balance as of September 28, 2013	$	3,835

Cash_Cash_Equivalents_and_Inve1

Cash, Cash Equivalents and Investments (Tables)	9 Months Ended
	Sep. 28, 2013
Cash, Cash Equivalents and Investments [Abstract]
Summary of cash, cash equivalents and short-term investments	Cadence’s cash, cash equivalents and short-term investments at fair value as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Cash and cash equivalents	$	620,403	$	726,357
	Short-term investments	96,019		100,704
	Cash, cash equivalents and short-term investments	$	716,422	$	827,061
Summary of cash and cash equivalents	The following table summarizes Cadence’s cash and cash equivalents at fair value as of September 28, 2013 and December 29, 2012:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Cash and interest bearing deposits	$	143,840	$	160,023
	Money market funds	475,563		566,334
	Bank certificates of deposit	1,000		—
	Total cash and cash equivalents	$	620,403	$	726,357
Summary of short-term investments	The following tables summarize Cadence’s short-term investments as of September 28, 2013 and December 29, 2012:
		As of September 28, 2013
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
		(In thousands)
	Corporate debt securities	$	36,859	$	33	$	(14	)	$	36,878
	Bank certificates of deposit	18,300		13		—			18,313
	United States Treasury securities	24,705		34		(1		)	24,738
	United States government agency securities	11,215		13		(1		)	11,227
	Commercial paper	2,794		3		—			2,797
	Marketable debt securities	93,873		96		(16		)	93,953
	Marketable equity securities	1,817		249		—			2,066
	Total short-term investments	$	95,690	$	345	$	(16	)	$	96,019
		As of December 29, 2012
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
		(In thousands)
	Corporate debt securities	$	31,313	$	57	$	(11	)	$	31,359
	Bank certificates of deposit	27,805		21		—			27,826
	United States Treasury securities	23,213		26		—			23,239
	United States government agency securities	10,245		13		—			10,258
	Commercial paper	5,777		6		—			5,783
	Marketable debt securities	98,353		123		(11		)	98,465
	Marketable equity securities	1,817		422		—			2,239
	Total short-term investments	$	100,170	$	545	$	(11	)	$	100,704
Contractual maturity of marketable debt investments	The amortized cost and estimated fair value of marketable debt securities included in short-term investments as of September 28, 2013, by contractual maturity, are shown in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without penalties.
		Amortized		Fair
		Cost		Value
		(In thousands)
	Due in less than one year	$	48,949	$	48,983
	Due in one to three years	44,924		44,970
	Total marketable debt securities included in short-term investments	$	93,873	$	93,953
Net realized gains on sale of marketable investments	Net realized gains from the sale of marketable debt and equity securities during the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended				Nine Months Ended
		September 28,		September 29,		September 28,			September 29,
		2013		2012		2013			2012
		(In thousands)				(In thousands)
	Gains on sale of marketable debt and equity securities, net	$	1,363	$	8	$	1,339		$	123
Carrying value of non-marketable securities	Cadence’s non-marketable investments as of September 28, 2013 and December 29, 2012 were as follows:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Cost method	$	3,038	$	3,038
	Equity method	3,648		4,249
	Total non-marketable investments	$	6,686	$	7,287
Net realized gains on the sale of non-marketable investments	Net realized gains on the sale of non-marketable investments during the three and nine months ended September 28, 2013 and September 29, 2012 were as follows:
		Three Months Ended				Nine Months Ended
		September 28,		September 29,		September 28,			September 29,
		2013		2012		2013			2012
		(In thousands)				(In thousands)
	Gains on sale of non-marketable investments, net	$	6	$	—	$	1,196		$	—

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	9 Months Ended
	Sep. 28, 2013
Earnings Per Share [Abstract]
Basic and diluted net income per share	The calculations for basic and diluted net income per share for the three and nine months ended September 28, 2013 and September 29, 2012 are as follows:
		Three Months Ended						Nine Months Ended
		September 28,			September 29,			September 28,		September 29,
		2013			2012			2013		2012
		(In thousands, except per share amounts)
	Net income	$	38,500		$	58,584		$	126,538	$	126,074
	Weighted average common shares used to calculate basic net income per share	278,977			271,350			277,034		269,643
	2023 Notes	9			11			11		11
	2015 Warrants	11,587			6,286			11,042		3,148
	Share-based awards	6,385			5,681			6,444		5,958
	Weighted average common shares used to calculate diluted net income per share	296,958			283,328			294,531		278,760
	Net income per share - basic	$	0.14		$	0.22		$	0.46	$	0.47
	Net income per share - diluted	$	0.13		$	0.21		$	0.43	$	0.45
Potential shares of Cadence's common stock excluded	The following table presents shares of Cadence’s common stock outstanding for the three and nine months ended September 28, 2013, and September 29, 2012, that were excluded from the computation of diluted net income per share because the effect of including these shares in the computation of diluted net income per share would have been anti-dilutive:
		Three Months Ended					Nine Months Ended
		September 28,		September 29,			September 28,		September 29,
		2013		2012			2013		2012
		(In thousands)
	2013 Warrants	6,830		6,830			6,830		6,830
	Options to purchase shares of common stock	5,639		10,003			6,048		12,767
	Non-vested shares of restricted stock	3,280		10			1,099		82
	Total potential common shares excluded	15,749		16,843			13,977		19,679

Other_Comprehensive_Income_Tab

Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 28, 2013
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income net of tax	Accumulated other comprehensive income was comprised of the following as of September 28, 2013, and December 29, 2012:
		As of
		September 28,			December 29,
		2013			2012
		(In thousands)
	Foreign currency translation gain	$	25,345		$	48,653
	Changes in defined benefit plan liabilities	(4,781		)	(5,229		)
	Unrealized holding gains on available-for-sale securities	320			526
	Total accumulated other comprehensive income	$	20,884		$	43,950
	For the three and nine months ended September 28, 2013 and September 29, 2012 there were no significant amounts reclassified from accumulated other comprehensive income to net income.

Other_Income_Net_Tables

Other Income, Net (Tables)	9 Months Ended
	Sep. 28, 2013
Other Income and Expenses [Abstract]
Other Income, Net	Cadence’s other income, net for the three and nine months ended September 28, 2013 and September 29, 2012 was as follows:
		Three Months Ended					Nine Months Ended
		September 28,		September 29,			September 28,			September 29,
		2013		2012			2013			2012
		(In thousands)
	Interest income	$	366	$	399		$	1,275		$	1,024
	Gains on sale of marketable debt and equity securities, net	1,363		8			1,339			123
	Gains on sale of non-marketable investments, net	6		—			1,196			—
	Gains (losses) on securities in NQDC trust	206		(839		)	2,057			3,237
	Gains on foreign exchange	489		1,376			1,476			2,546
	Write-down of non-marketable investments	—		(1,081		)	(464		)	(1,103		)
	Other income (expense), net	105		6			(151		)	145
	Total other income (expense), net	$	2,535	$	(131	)	$	6,728		$	5,972

Segment_Reporting_Tables

Segment Reporting (Tables)	9 Months Ended
	Sep. 28, 2013
Segment Reporting [Abstract]
Summary of revenue by geography	The following table presents a summary of revenue by geography for the three and nine months ended September 28, 2013 and September 29, 2012:
		Three Months Ended				Nine Months Ended
		September 28,		September 29,		September 28,		September 29,
		2013		2012		2013		2012
		(In thousands)
	Americas:
	United States	$	168,125	$	141,509	$	476,525	$	414,888
	Other Americas	7,212		4,733		17,393		18,659
	Total Americas	175,337		146,242		493,918		433,547
	Europe, Middle East and Africa	72,376		66,392		229,053		191,097
	Japan	45,853		58,757		144,794		168,856
	Asia	73,081		67,142		215,629		187,339
	Total	$	366,647	$	338,533	$	1,083,394	$	980,839
Summary of long-lived assets by geography	The following table presents a summary of long-lived assets by geography as of September 28, 2013 and December 29, 2012:
		As of
		September 28,		December 29,
		2013		2012
		(In thousands)
	Americas:
	United States	$	209,783	$	214,711
	Other Americas	330		185
	Total Americas	210,113		214,896
	Europe, Middle East and Africa	6,354		5,410
	Japan	974		1,649
	Asia	24,524		22,484
	Total	$	241,965	$	244,439

Debt_Details

Debt (Details) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Principal	$544,561	$494,639
Unamortized debt discount	-30,724	-47,628
Carrying value	50,000	0
Carrying value	513,837	447,011
Notes Due Twenty-Thirteen [Member]
Debt Instrument [Line Items]
Principal	144,461	144,461
Unamortized debt discount	-1,449	-6,447
Carrying value	143,012	138,014
Convertible Senior Notes Due 2015 [Member]
Debt Instrument [Line Items]
Principal	350,000	350,000
Unamortized debt discount	-29,275	-41,181
Carrying value	320,725	308,819
Zero Coupon Zero Yield Senior Convertible Notes Due Two Zero Two Three [Member]
Debt Instrument [Line Items]
Principal	100	178
Unamortized debt discount	0	0
Carrying value	100	178
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal	50,000	0
Unamortized debt discount	0	0
Carrying value	$50,000	$0

Debt_Details_1

Debt (Details 1) (Convertible Senior Notes Due 2015 [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Convertible Senior Notes Due 2015 [Member]
Effective interest rate and components of interest expense of 2015 notes
Effective interest rate	8.10%	8.10%	8.10%	8.10%
Contractual interest expense	$2,289	$2,289	$6,867	$6,867
Amortization of debt discount	$4,045	$3,737	$11,906	$10,968

Debt_Details_2

Debt (Details 2) (Convertible Senior Notes Due 2013 [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Convertible Senior Notes Due 2013 [Member]
Effective interest rate and components of interest expense of 2013 notes
Effective interest rate	6.40%	6.40%	6.40%	6.40%
Contractual interest expense	$540	$540	$1,619	$1,619
Amortization of debt discount	$1,691	$1,588	$4,998	$4,674

Debt_Details_Textual

Debt (Details Textual) (USD $)	Sep. 28, 2013	Dec. 29, 2012	Sep. 28, 2013	Jan. 01, 2011	Dec. 30, 2006	Dec. 29, 2012	Jun. 30, 2010	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Dec. 29, 2012	Sep. 28, 2013	Dec. 29, 2012	Aug. 31, 2003
			Convertible Senior Notes Due 2013 [Member]	Convertible Senior Notes Due 2013 [Member]	Convertible Senior Notes Due 2013 [Member]	Convertible Senior Notes Due 2013 [Member]	Convertible Senior Notes Due 2015 [Member]	Convertible Senior Notes Due 2015 [Member]	Convertible Senior Notes Due 2015 [Member]	Convertible Senior Notes Due 2015 [Member]	Convertible Senior Notes Due 2015 [Member]	Convertible Senior Notes Due 2015 [Member]	Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]
Convertible Notes (Textual) [Abstract]
Principal amount, issued					$250,000,000		$350,000,000								$420,000,000
Principal amount outstanding			144,461,000			144,461,000		350,000,000		350,000,000		350,000,000	100,000	178,000
Stated interest rate of Convertible Senior Notes			1.50%					2.63%		2.63%
Net current liability of convertible senior notes	463,837,000	447,011,000						320,700,000		320,700,000
Equity component of convertible debt - included in common stock			63,027,000			63,027,000
Maturity date of Convertible Senior Notes			15-Dec-13							1-Jun-15
Warrants to purchase shares of common stock price per share (in usd per share)			$31.50							$10.78
Conversion rate of Notes			47.2813 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $21.15 per share of Cadence common stock.							132.5205 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $7.55 per share of Cadence common stock.
Minimum closing price of common stock for specified days for conversion of notes (in usd per share)			$27.50							$9.81
Minimum number of trading days limit for which closing price exceeds fixed price for conversion of notes			20 days							20 days
Number of final trading days range within which closing price exceeds the fixed price for conversion of notes			30 days							30 days
Total expense if convertible notes are converted										33,300,000
Unamortized debt discount expensed if convertible notes are converted										29,300,000
Unamortized transaction fees expensed if convertible notes are converted										4,000,000
If converted value of convertible senior notes								628,500,000		628,500,000
Event 1			Closing stock price greater than $27.50 for at least 20 of the last 30 trading days in a calendar quarter (convertible only for subsequent quarter).							Closing stock price greater than $9.81 for at least 20 of the last 30 trading days in a fiscal quarter (convertible only for subsequent quarter).
Event 2			Specified corporate transactions							Specified corporate transactions
Event 3			Note trading price falls below calculated minimum							Note trading price falls below a calculated minimum
Conversion rate of Convertible Senior Notes subject to certain conversion rate adjustments (in usd per share)			$21.15					$7.55		$7.55
Condition 1			Upon a fundamental change prior to maturity, the 2013 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest. Upon certain fundamental changes, prior to maturity, if Cadence’s stock price were between $18.00 and $60.00 per share at that time, the 2013 Note holder would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”							Upon certain fundamental corporate changes prior to maturity, the 2015 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest. Upon certain fundamental changes prior to maturity, if Cadence’s stock price were between $6.16 and $40.00 per share at that time, the 2015 notes holder would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
Minimum closing price of common stock to make whole premium in the form of increase to conversion rate (in usd per share)			$18							$6.16
Maximum closing price of common stock to make whole premium in form of increase to conversion rate (in usd per share)			$60							$40
Conversion rate for convertible senior notes per thousand principal amount of notes			47.2813							132.5205
Debt instrument principal amount conversion rate for specified shares of common stock			1,000							1,000
Total estimated fair value								639,400,000		639,400,000		640,100,000	100,000	178,000
Fair value of 2015 notes embedded conversion Derivative at the time of issuance							76,600,000
Estimated fair value of 2015 Notes embedded conversion derivative at the balance sheet date								292,500,000		292,500,000		303,200,000
Cost of 2015 Notes Hedges							76,600,000
Estimated fair value of 2015 Notes hedges at the balance sheet date								292,500,000		292,500,000		303,200,000
Shares of common stock that can be purchased under warrants (in shares)					11,800,000					46,400,000
Amount received in cash proceeds from the sale of warrants					25,300,000		37,500,000
Number of shares underlying warrants purchased with purchase of convertible Senior Notes				5,000,000
Notes Warrants expiration date description			various dates from February 2014 through April 2014							various dates from September 2015 through December 2015
Aggregate cost of 2013 Notes Hedges					67,700,000
Estimated fair value of the remaining 2013 Notes Hedges			0			700,000
Number of shares underlying warrants purchased with purchase of 2013 Notes (in shares)				5,000,000
Total estimated fair value (including equity component)			144,700,000			144,100,000
Impact on Income statement related to fair value adjustments of 2015 Notes Embedded Conversion Derivative and 2015 Notes Hedges								$0	$0	$0	$0

Debt_Credit_Facility_Details_T

Debt Credit Facility (Details Textual) (USD $)	9 Months Ended
	Sep. 28, 2013	Dec. 29, 2012
Line of Credit Facility [Line Items]
Revolving credit facility	$50,000,000	$0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, date of agreement	12-Dec-12
Credit facility, interest rate description	Interest accrues based on Cadence's consolidated leverage ratio. Borrowings may be made at LIBOR plus a margin between 1.25% and 2.0% per annum or at the base rate plus a margin between 0.25% and 1.0% per annum, where in each case the margin is determined by reference to a specified leverage ratio. Interest is payable quarterly.
Credit facility, term	5 years
Credit facility, current borrowing capacity	250,000,000
Credit facility additional borrowing capacity available	150,000,000
Credit facility, maximum borrowing capacity	400,000,000
Credit facility, maturity date	12-Dec-17
Credit facility, collateral description	The facility is secured by certain accounts receivable and certain equity interests in Cadence’s subsidiaries.
Credit facility, covenant description	The credit facility contains customary negative covenants that, among other things, restrict Cadence's ability to incur additional indebtedness, grant liens and make certain investments, make acquisitions, dispose of certain assets and make certain restricted payments, including dividends. In addition, the credit facility contains financial covenants that require Cadence to maintain a leverage ratio not to exceed 3 to 1, and a minimum interest coverage ratio of 3 to 1.
Revolving credit facility	$50,000,000	$0
Credit facility, covenant compliance	Cadence was in compliance with all financial covenants as of September 28, 2013 and December 29, 2012.
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.35%
Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.20%
Credit Facility Interest LIBOR And Spread [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	2.00%
Credit Facility Interest LIBOR And Spread [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	1.25%
Credit facility interest base rate and spread [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	1.00%
Credit facility interest base rate and spread [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	0.25%

Acquisitions_and_AcquisitionRe2

Acquisitions and Acquisition-Related Contingent Consideration (Details Textual) (USD $)	3 Months Ended		9 Months Ended				3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Apr. 22, 2013	23-May-13	23-May-13	Sep. 28, 2013
					Tensilica	Cosmic	Cosmic	Other 2013 acquisitions
							Trust For benefit of children of chief executive officer [Member]
Business Acquisition [Line Items]
Total considerations paid								$14.40
Total consideration paid, net of cash acquired					319.3	59.5
Cash acquired					26.3	1.7
Business acquisition total fair value of options assumed					15.3
Business acquisition fair value of options assumed as consideration					0.5
Business acquisition fair value of options assumed to be expensed over service period of award					14.8
Additional payments deferred on the acquisition date					5.8
Related party, ownership percentage in acquired company							8.50%
Acquired definite-lived intangible assets, weighted average useful life			8 years
Goodwill, expected tax deductible amount	9.6		9.6
Acquisition related costs	$0	$0.20	$8.20	$1.30

Acquisitions_and_AcquisitionRe3

Acquisitions and Acquisition-Related Contingent Consideration Acquisitions and Acquisition-Related Contingent Consideration (Details) (USD $)	Apr. 22, 2013	Apr. 22, 2013	Apr. 22, 2013	Apr. 22, 2013	23-May-13	23-May-13	23-May-13	23-May-13	Sep. 28, 2013	Sep. 28, 2013	Sep. 28, 2013	Sep. 28, 2013
In Thousands, unless otherwise specified	Tensilica	Tensilica existing technology	Tensilica agreements and relationships	Tensilica tradenames and trademarks	Cosmic	Cosmic existing technology	Cosmic agreements and relationships	Cosmic tradenames and trademarks	Other 2013 acquisitions	Other acquisitions agreements and relationships	Other acquisitions existing technology	Other acquisitions tradenames and trademarks
Business Acquisition [Line Items]
Cash and cash equivalents	$26,331				$1,724				$149
Trade receivables	4,454				668				0
Property, plant and equipment	1,938				185				91
Other assets	46,832				1,681				0
Acquired intangibles:		102,000	33,000	3,000		16,300	5,100	0		1,667	2,014	0
In-process technology	5,300				4,200				1,200
Goodwill	176,461				41,911				9,587
Total assets acquired	399,316				71,769				14,708
Deferred revenue	-8,100				-129				0
Other liabilities	-4,959				-1,982				-277
Long-term deferred tax liabilities	-40,147				-8,428				0
Net assets acquired	$346,110				$61,230				$14,431

Acquisitions_and_AcquisitionRe4

Acquisitions and Acquisition-Related Contingent Consideration Acquisitions and Acquisition-Related Contingent Consideration (Details 1) (Tensilica, USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Tensilica
Schedule of Business Acquisitions, Pro Forma [Line Items]
Pro forma revenue	$368,694	$346,999	$1,101,689	$1,003,170
Pro forma net income	$43,679	$47,180	$131,753	$85,280

Acquisitions_and_AcquisitionRe5

Acquisitions and Acquisition-Related Contingent Consideration (Details Textual 1) (USD $)	9 Months Ended		12 Months Ended
	Sep. 28, 2013	Dec. 29, 2012	Dec. 31, 2011	Sep. 28, 2013
			Two Thousand Eleven Acquisition [Member]	Two Thousand Eleven Acquisition [Member]
Business Acquisition, Contingent Consideration [Line Items]
Maximum payments for contingent consideration arrangement			$5,000,000
Time of certain financial measures subsequent to consummation of the acquisition related to contingent consideration			3 years
Beginning date of acquisition related contingent consideration measurement period			subsequent to October 1, 2011
Acquisition related contingent consideration at initial fair value			3,500,000
Acquisition-related contingent consideration	3,835,000	4,218,000		3,800,000
Maximum amount obligated to pay by Cadence	14,300,000
Period over which consideration may be paid	31 months
Portion of amount of contingent consideration potential expense in future periods	$8,700,000

Goodwill_and_Acquired_Intangib2

Goodwill and Acquired Intangibles (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013
Changes in the carrying amount of goodwill
Balance as of December 29, 2012	$233,266
Goodwill resulting from acquisitions	227,959
Effect of foreign currency translation	-4,958
Balance as of September 28, 2013	$456,267

Goodwill_and_Acquired_Intangib3

Goodwill and Acquired Intangibles (Details 1) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Dec. 29, 2012
Finite-Lived Intangible Assets [Line Items]
In-process Technology Transferred to Existing Technology	$5,496
Acquired intangibles with finite lives, excluding intangibles fully amortized at end of prior fiscal year
Gross carrying amount	451,811	289,289
Accumulated amortization	-128,004	-104,351
Acquired intangibles	323,807	184,938
In-process technology	3,996
Existing Technology [Member]
Acquired intangibles with finite lives, excluding intangibles fully amortized at end of prior fiscal year
Gross carrying amount	236,774	112,940
Accumulated amortization	-46,170	-30,171
Acquired intangibles	190,604	82,769
Agreements and relationships [Member]
Acquired intangibles with finite lives, excluding intangibles fully amortized at end of prior fiscal year
Gross carrying amount	171,422	133,764
Accumulated amortization	-49,199	-37,769
Acquired intangibles	122,223	95,995
Distribution rights [Member]
Acquired intangibles with finite lives, excluding intangibles fully amortized at end of prior fiscal year
Gross carrying amount	30,100	30,100
Accumulated amortization	-30,100	-28,595
Acquired intangibles	0	1,505
Tradenames Trademarks And Patents [Member]
Acquired intangibles with finite lives, excluding intangibles fully amortized at end of prior fiscal year
Gross carrying amount	9,519	12,485
Accumulated amortization	-2,535	-7,816
Acquired intangibles	$6,984	$4,669
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected Completion for In-process Technology	6 months
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected Completion for In-process Technology	12 months

Goodwill_and_Acquired_Intangib4

Goodwill and Acquired Intangibles (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Amortization of acquired intangibles
Cost of product and maintenance	$7,191	$3,874	$16,758	$9,664
Amortization of Intangible Assets	5,141	3,876	14,259	11,305
Total amortization of acquired intangibles	$12,332	$7,750	$31,017	$20,969

Goodwill_and_Acquired_Intangib5

Goodwill and Acquired Intangibles (Details 3) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Estimated amortization expense
2013-remaining period	$12,446
2014	49,929
2015	49,378
2016	43,666
2017	40,060
Thereafter	128,328
Acquired intangibles	$323,807	$184,938

Income_Taxes_Income_Taxes_Deta

Income Taxes Income Taxes (Details Textual) (USD $)	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Income Tax Disclosure [Abstract]
Income tax expense	$2,382,000	($8,011,000)	$3,025,000	$9,469,000
Tax benefit from release of uncertain tax position from previous business combination	33,700,000		33,700,000
Tax benefit for fiscal 2012 federal research tax credit			$5,900,000

Income_Taxes_Income_Taxes_Deta1

Income Taxes Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Dec. 29, 2012
Unrecognized tax benefits
Unrecognized tax benefits as of December 29, 2012			$92,378
Gross amount of the increases in unrecognized tax benefits of tax positions taken during a prior year			6,476
Gross amount of the increases in unrecognized tax benefits as a result of tax positions taken during the current year			13,088
Amount of decreases in unrecognized tax benefits relating to settlements with taxing authorities, including the utilization of tax attributes			-13,821
Reductions to unrecognized tax benefits resulting from the lapse of the applicable statute of limitations			-12,044
Effect of foreign currency translation			497
Unrecognized tax benefits as of September 28, 2013	86,574		86,574
Total amounts of unrecognized tax benefits that, if upon resolution of the uncertain tax positions would reduce Cadence's effective tax rate as of September 28, 2013	49,914		49,914
Interest and penalties recognized in the condensed consolidated income statements
Interest	728	820	-12,731	2,584
Penalties	-708	-36	-7,666	-1,012
Interest and penalties recognized in the condensed consolidated balance sheets
Interest	52		52		24,427
Penalties	$1,255		$1,255		$8,953

Receivables_and_Allowances_for2

Receivables and Allowances for Doubtful Accounts (Details) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Current and long-term receivables balances
Accounts receivable	$61,906	$67,259
Installment contract receivables, short-term	40,134	30,647
Long-term receivables	3,994	7,559
Total receivables	106,034	105,465
Less allowance for doubtful accounts	-144	-85
Total receivables, net	$105,890	$105,380

Receivables_and_Allowances_for3

Receivables and Allowances for Doubtful Accounts (Details Textual)	Sep. 28, 2013	Dec. 29, 2012
	Customer	Customer
Accounts Receivable and Allowances for Doubtful Accounts (Textual) [Abstract]
Percentage of Company's Receivables Net and Installment Contract Receivables Net Attributable to Single Customer	13.00%	10.00%
Number of customers with receivables balance greater than ten percent of total balance		0
Percentage of Company's total receivables, net attributable to the ten customers with largest balance	53.00%	47.00%
Number of customers with largest balance of receivables	10	10

Fair_Value_Details

Fair Value (Details) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Short-term investments:
Available-for-sale securities	$96,019	$100,704
Trading securities held in Non - Qualified Deferred Compensation Plan, or NQDC, trust	22,339	24,329
2015 Notes Hedges	292,511	303,154
Foreign currency exchange contracts	1,662	1,737
Total Assets	889,094	996,258
Liabilities
Acquisition-related contingent consideration	3,835	4,218
2015 Notes Embedded Conversion Derivative	292,511	303,154
Total Liabilities	296,346	307,372
Money market funds [Member]
Assets
Cash equivalents	475,563	566,334
Corporate debt securities [Member]
Short-term investments:
Available-for-sale securities	36,878	31,359
Bank certificates of deposit [Member]
Assets
Cash equivalents	1,000
Short-term investments:
Available-for-sale securities	18,313	27,826
United States Treasury securities [Member]
Short-term investments:
Available-for-sale securities	24,738	23,239
United States government agency securities [Member]
Short-term investments:
Available-for-sale securities	11,227	10,258
Commercial paper [Member]
Short-term investments:
Available-for-sale securities	2,797	5,783
Marketable equity securities [Member]
Short-term investments:
Available-for-sale securities	2,066	2,239
Fair Value Measurements, Level 1 [Member]
Short-term investments:
Trading securities held in Non - Qualified Deferred Compensation Plan, or NQDC, trust	22,339	24,329
2015 Notes Hedges	0	0
Foreign currency exchange contracts	0	0
Total Assets	535,933	626,399
Liabilities
Acquisition-related contingent consideration	0	0
2015 Notes Embedded Conversion Derivative	0	0
Total Liabilities	0	0
Fair Value Measurements, Level 1 [Member] | Money market funds [Member]
Assets
Cash equivalents	475,563	566,334
Fair Value Measurements, Level 1 [Member] | Corporate debt securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 1 [Member] | Bank certificates of deposit [Member]
Assets
Cash equivalents	0
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 1 [Member] | United States Treasury securities [Member]
Short-term investments:
Available-for-sale securities	24,738	23,239
Fair Value Measurements, Level 1 [Member] | United States government agency securities [Member]
Short-term investments:
Available-for-sale securities	11,227	10,258
Fair Value Measurements, Level 1 [Member] | Commercial paper [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 1 [Member] | Marketable equity securities [Member]
Short-term investments:
Available-for-sale securities	2,066	2,239
Fair Value Measurements, Level 2 [Member]
Short-term investments:
Trading securities held in Non - Qualified Deferred Compensation Plan, or NQDC, trust	0	0
2015 Notes Hedges	292,511	303,154
Foreign currency exchange contracts	1,662	1,737
Total Assets	353,161	369,859
Liabilities
Acquisition-related contingent consideration	0	0
2015 Notes Embedded Conversion Derivative	292,511	303,154
Total Liabilities	292,511	303,154
Fair Value Measurements, Level 2 [Member] | Money market funds [Member]
Assets
Cash equivalents	0	0
Fair Value Measurements, Level 2 [Member] | Corporate debt securities [Member]
Short-term investments:
Available-for-sale securities	36,878	31,359
Fair Value Measurements, Level 2 [Member] | Bank certificates of deposit [Member]
Assets
Cash equivalents	1,000
Short-term investments:
Available-for-sale securities	18,313	27,826
Fair Value Measurements, Level 2 [Member] | United States Treasury securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 2 [Member] | United States government agency securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 2 [Member] | Commercial paper [Member]
Short-term investments:
Available-for-sale securities	2,797	5,783
Fair Value Measurements, Level 2 [Member] | Marketable equity securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member]
Short-term investments:
Trading securities held in Non - Qualified Deferred Compensation Plan, or NQDC, trust	0	0
2015 Notes Hedges	0	0
Foreign currency exchange contracts	0	0
Total Assets	0	0
Liabilities
Acquisition-related contingent consideration	3,835	4,218
2015 Notes Embedded Conversion Derivative	0	0
Total Liabilities	3,835	4,218
Fair Value Measurements, Level 3 [Member] | Money market funds [Member]
Assets
Cash equivalents	0	0
Fair Value Measurements, Level 3 [Member] | Corporate debt securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member] | Bank certificates of deposit [Member]
Assets
Cash equivalents	0
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member] | United States Treasury securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member] | United States government agency securities [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member] | Commercial paper [Member]
Short-term investments:
Available-for-sale securities	0	0
Fair Value Measurements, Level 3 [Member] | Marketable equity securities [Member]
Short-term investments:
Available-for-sale securities	$0	$0

Fair_Value_Details_1

Fair Value (Details 1) (USD $)	Sep. 28, 2013	Dec. 29, 2012	Sep. 28, 2013
In Thousands, unless otherwise specified			Fair Value Measurements, Level 3 [Member]
Liabilities included in level 3 representing fair value of contingent consideration associated with acquisitions
Begining Balance	$3,835	$4,218	$4,218
Payments			-835
Adjustments			452
Ending Balance	$3,835	$4,218	$3,835

Fair_Value_Details_Textual

Fair Value (Details Textual) (USD $)	9 Months Ended	12 Months Ended
	Sep. 28, 2013	Dec. 29, 2012
2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Acquired Intangible Assets, Amount	173,800,000
Deferred Revenue	-8,200,000
Intangible Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | 2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Discount Rate	10.00%
Intangible Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | 2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Discount Rate	15.00%
Deferred Revenue [Member] | Fair Value, Inputs, Level 3 [Member] | 2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Discount Rate	3.00%
Deferred Revenue [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | 2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Estimated Profit Rate	10.00%
Deferred Revenue [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | 2013 Acquisitions [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Estimated Profit Rate	25.00%
Contingent Consideration Liability [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Discount Rate	11.00%	11.00%
Contingent Consideration Liability [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member]
Fair Value of Financial Instrument (Textual) [Abstract]
Fair Value Inputs, Discount Rate	16.00%	16.00%

Cash_Cash_Equivalents_and_Inve2

Cash, Cash Equivalents and Investments (Details) (USD $)	Sep. 28, 2013	Dec. 29, 2012	Sep. 29, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Cash, Cash Equivalents and Investments [Abstract]
Cash and cash equivalents	$620,403	$726,357	$649,099	$601,602
Short-term investments	96,019	100,704
Cash, cash equivalents, and short-term investments	$716,422	$827,061

Cash_Cash_Equivalents_and_Inve3

Cash, Cash Equivalents and Investments (Details 1) (USD $)	Sep. 28, 2013	Dec. 29, 2012	Sep. 29, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Classified as cash and cash equivalents
Cash and interest bearing deposits	$143,840	$160,023
Money market funds	475,563	566,334
Bank certificates of deposit	1,000	0
Total cash and cash equivalents	$620,403	$726,357	$649,099	$601,602

Cash_Cash_Equivalents_and_Inve4

Cash, Cash Equivalents and Investments (Details 2) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Dec. 29, 2012
Short-term investments
Amortized Cost	$95,690	$100,170
Gross Unrealized Gains	345	545
Gross Unrealized Losses	-16	-11
Fair Value	96,019	100,704
Corporate debt securities [Member]
Short-term investments
Amortized Cost	36,859	31,313
Gross Unrealized Gains	33	57
Gross Unrealized Losses	-14	-11
Fair Value	36,878	31,359
Bank certificates of deposit [Member]
Short-term investments
Amortized Cost	18,300	27,805
Gross Unrealized Gains	13	21
Gross Unrealized Losses	0	0
Fair Value	18,313	27,826
US Treasury Securities [Member]
Short-term investments
Amortized Cost	24,705	23,213
Gross Unrealized Gains	34	26
Gross Unrealized Losses	-1	0
Fair Value	24,738	23,239
US Government Corporations and Agencies Securities [Member]
Short-term investments
Amortized Cost	11,215	10,245
Gross Unrealized Gains	13	13
Gross Unrealized Losses	-1	0
Fair Value	11,227	10,258
Commercial paper [Member]
Short-term investments
Amortized Cost	2,794	5,777
Gross Unrealized Gains	3	6
Gross Unrealized Losses	0	0
Fair Value	2,797	5,783
Marketable debt securities [Member]
Short-term investments
Amortized Cost	93,873	98,353
Gross Unrealized Gains	96	123
Gross Unrealized Losses	-16	-11
Fair Value	93,953	98,465
Marketable equity securities [Member]
Short-term investments
Amortized Cost	1,817	1,817
Gross Unrealized Gains	249	422
Gross Unrealized Losses	0	0
Fair Value	$2,066	$2,239

Cash_Cash_Equivalents_and_Inve5

Cash, Cash Equivalents and Investments (Details 3) (USD $)	Sep. 28, 2013
In Thousands, unless otherwise specified
Contractual maturity of marketable debt investments
Marketable Investments, Debt Maturities, Within One Year, Amortized Cost	$48,949
Marketable Investments, Debt Maturities, Year One Through Three, Amortized Cost	44,924
Marketable investments, Debt Maturities, Amortized Cost, Total	93,873
Marketable Investments, Debt Maturities, Within One Year, Fair Value	48,983
Marketable Investments, Debt Maturities, Year One Through Three, Fair Value	44,970
Marketable Investments, Debt Maturities, Fair Value, Total	$93,953

Cash_Cash_Equivalents_and_Inve6

Cash, Cash Equivalents and Investments (Details 4) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Carrying value of non-marketable investments
Cost method	$3,038	$3,038
Equity method	3,648	4,249
Total non-marketable investments	$6,686	$7,287

Cash_Cash_Equivalents_and_Inve7

Cash, Cash Equivalents and Investments (Details 5) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Summary of realized gains from sale of marketable securities
Gains on sale of marketable debt and equity securities, net	$1,363	$8	$1,339	$123
Summary of realized gains from sale of non-marketable securities
Gains on sale of non-marketable investments, net	$6	$0	$1,196	$0

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Earnings Per Share, Basic and Diluted [Abstract]
Net income	$38,500	$58,584	$126,538	$126,074
Weighted-average common shares used to calculate basic net income per share (in shares)	278,977	271,350	277,034	269,643
2023 Notes	9	11	11	11
2015 Warrants	11,587	6,286	11,042	3,148
Share-based awards	6,385	5,681	6,444	5,958
Weighted average common shares used to calculate diluted net income per share (in shares)	296,958	283,328	294,531	278,760
Net income per share - basic (in usd per share)	$0.14	$0.22	$0.46	$0.47
Net income per share - diluted (in usd per share)	$0.13	$0.21	$0.43	$0.45

Net_Income_Per_Share_Details_1

Net Income Per Share (Details 1)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Potential shares of Cadence's common stock excluded
Total potential common shares excluded	15,749	16,843	13,977	19,679
2013 Warrants
Potential shares of Cadence's common stock excluded
Total potential common shares excluded	6,830	6,830	6,830	6,830
Options to purchase shares of common stock
Potential shares of Cadence's common stock excluded
Total potential common shares excluded	5,639	10,003	6,048	12,767
Non-vested shares of restricted stock
Potential shares of Cadence's common stock excluded
Total potential common shares excluded	3,280	10	1,099	82

Other_Comprehensive_Income_Det

Other Comprehensive Income (Details 1) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Accumulated other comprehensive income
Foreign currency translation gain	$25,345	$48,653
Changes in defined benefit plan liabilities	-4,781	-5,229
Unrealized holding gains on available-for-sale securities	320	526
Total accumulated other comprehensive income	$20,884	$43,950

Contingencies_Details_Textual

Contingencies (Details Textual)	9 Months Ended
	Sep. 28, 2013
Contingencies (Textual) [Abstract]
General period of warranty on sales of hardware products	90 days

Other_Income_Net_Details

Other Income, Net (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Other Income, Net
Interest income	$366	$399	$1,275	$1,024
Gains on sale of marketable debt and equity securities, net	1,363	8	1,339	123
Gains on sale of non-marketable investments, net	6	0	1,196	0
Gains (losses) on securities in NQDC trust	206	-839	2,057	3,237
Gains on foreign exchange	489	1,376	1,476	2,546
Write-down of non-marketable investments	0	-1,081	-464	-1,103
Other income (expense), net	105	6	-151	145
Total other income (expense), net	$2,535	($131)	$6,728	$5,972

Segment_Reporting_Details

Segment Reporting (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Total revenue	$366,647	$338,533	$1,083,394	$980,839
Americas:
Total Americas	175,337	146,242	493,918	433,547
United States [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	168,125	141,509	476,525	414,888
Other Americas [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	7,212	4,733	17,393	18,659
EMEA [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	72,376	66,392	229,053	191,097
Japan [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	45,853	58,757	144,794	168,856
Asia [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	$73,081	$67,142	$215,629	$187,339

Segment_Reporting_Details_1

Segment Reporting (Details 1) (USD $)	Sep. 28, 2013	Dec. 29, 2012
In Thousands, unless otherwise specified
Summary of long-lived assets by geography
Total long-lived assets	$241,965	$244,439
Americas:
Total Americas	210,113	214,896
United States [Member]
Summary of long-lived assets by geography
Long-Lived Assets in Individual Foreign Countries	209,783	214,711
Other Americas [Member]
Summary of long-lived assets by geography
Long-Lived Assets in Individual Foreign Countries	330	185
EMEA [Member]
Summary of long-lived assets by geography
Long-Lived Assets in Individual Foreign Countries	6,354	5,410
Japan [Member]
Summary of long-lived assets by geography
Long-Lived Assets in Individual Foreign Countries	974	1,649
Asia [Member]
Summary of long-lived assets by geography
Long-Lived Assets in Individual Foreign Countries	$24,524	$22,484