PMC Sierra (PMCS) 10-Q 7 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 28, 2015	Apr. 29, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	28-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	pmcs
Entity Registrant Name	PMC SIERRA INC
Entity Central Index Key	767920
Current Fiscal Year End Date	-14
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		197,891,832
Entity Current Reporting Status	Yes

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Operations (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015		Mar. 29, 2014
Condensed Consolidated Statements Of Operations [Abstract]
Net revenues	$133,071		$126,468
Cost of revenues (excluding amortization of purchased intangible assets below)	39,980		37,564
Gross profit	93,091		88,904
Other costs and expenses:
Research and development, net	48,866		50,148
Selling, general and administrative	30,051		29,340
Amortization of purchased intangible assets	9,317		12,329
Income (loss) from operations	4,857		-2,913
Other income (expense):
Foreign exchange gain	2,594		532
Interest and other financial income, net	164		9
Gain on investment securities and other investments	32		29
Amortization of debt issuance costs	-51		-51
Amortization of discount on short-term and long-term obligation	-210
Income (loss) before provision for income taxes	7,386		-2,394
Provision for income taxes	-2,731		-1,847
Net income (loss)	$4,655		($4,241)
Net income (loss) per common share - basic and diluted	$0.02		($0.02)
Shares used in per share calculation - basic	200,249		195,188
Shares used in per share calculation - diluted	205,688	[1]	195,188	[1]
[1]	PMC-Sierra Ltd. special shares are included in the calculation of basic and diluted weighted average common shares outstanding.

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements Of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Condensed Consolidated Statements Of Comprehensive Loss [Abstract]
Net income (loss)	$4,655	($4,241)
Other comprehensive income (loss):
Change in fair value of derivatives, net of tax of $nil and $57	-334	-163
Change in fair value of investment securities, net of tax of $nil and ($6)	504	16
Other comprehensive income (loss)	170	-147
Comprehensive income (loss)	$4,825	($4,388)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Comprehensive Loss (Parenthetical) (USD $)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014
Condensed Consolidated Statements Of Comprehensive Loss [Abstract]
Change in fair value of derivatives, deferred tax expense (benefit)	$0	$57,000
Change in fair value of investment securities, deferred tax expense (benefit).	$0	($6,000)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$64,548	$112,570
Short-term investments	45,580	45,885
Accounts receivable, net of allowance for doubtful accounts of $795 (2014 - $795)	62,156	55,414
Inventories, net	35,685	37,949
Prepaid expenses and other current assets	14,348	16,473
Income taxes receivable	1,966	1,968
Prepaid income tax expenses		51
Deferred income tax assets	5,255	5,442
Total current assets	229,538	275,752
Investment securities	120,052	107,509
Investments and other assets	7,332	7,683
Prepaid income tax expenses	93	42
Property and equipment, net	37,370	37,311
Goodwill	283,239	283,239
Intangible assets, net	133,344	143,680
Deferred income tax assets	13,123	13,412
Income taxes receivable	465	457
Assets, Total	824,556	869,085
Current liabilities:
Accounts payable	20,357	23,360
Accrued liabilities	53,788	74,135
Credit facility	10,000
Income taxes payable	1,109	1,062
Liability for unrecognized tax benefit	14,820	16,076
Deferred income tax liabilities	7,644	7,644
Deferred income	3,944	4,530
Total current liabilities	111,662	126,807
Long-term obligations	25,008	36,305
Deferred income tax liabilities	54,209	53,493
Liability for unrecognized tax benefit	25,768	25,244
PMC special shares convertible into 205 (2014 - 278) shares of common stock	480	745
Stockholders' equity:
Common stock, par value $.001: 900,000 shares authorized; 197,726 shares issued and outstanding (2014 - 199,518)	198	200
Additional paid in capital	1,603,388	1,595,609
Accumulated other comprehensive loss	-2,185	-2,355
Accumulated deficit	-993,972	-966,963
Total stockholders' equity	607,429	626,491
Liabilities and Stockholders' Equity, Total	$824,556	$869,085

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, except Share data, unless otherwise specified
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$795	$795
PMC special shares convertible into common stock, shares	205,000	278,000
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	197,726,000	199,518,000
Common stock, shares outstanding	197,726,000	199,518,000

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Cash flows from operating activities:
Net income (loss)	$4,655	($4,241)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	14,988	17,911
Stock-based compensation	6,693	6,191
Unrealized foreign exchange gain, net	-4,495	-1,725
Net amortization of premiums and accrued interest of investments	256	275
Asset impairments		770
Gain on investment securities and other	-32	-29
Accretion of discount on short-term and long-term obligations	210
Amortization of debt issue costs	51	51
Changes in operating assets and liabilities:
Accounts receivable, net	-6,741	-546
Inventories, net	2,264	864
Prepaid expenses and other current assets	834	2,324
Accounts payable and accrued liabilities	-12,726	-11,689
Deferred taxes and income taxes payable	2,664	2,374
Deferred income	-586	-1,921
Net cash provided by operating activities	8,035	10,609
Cash flows from investing activities:
Purchases of property and equipment	-4,414	-3,732
Purchase of intangible assets	-441	-481
Redemption of short-term investments	7,926	1,800
Disposals of investment securities and other investments	15,429	14,064
Purchases of investment securities and other investments	-35,329	-17,790
Net cash used in investing activities	-16,829	-6,139
Cash flows from financing activities:
Cash paid in connection with business acquisition	-18,000
Proceeds from credit facility	30,000	30,000
Repayment of credit facility	-20,000	-55,000
Proceeds from issuance of common stock	26,759	9,348
Repurchases of common stock	-57,222	-11,496
Net cash used in financing activities	-38,463	-27,148
Effect of exchange rate changes on cash and cash equivalents	-765	-432
Net decrease in cash and cash equivalents	-48,022	-23,110
Cash and cash equivalents, beginning of period	112,570	100,038
Cash and cash equivalents, end of period	64,548	76,928
Supplemental disclosures of cash flow information:
Cash paid for interest	101	198
Cash (payments) refunds received for income taxes, net	($69)	$654

Summary_Of_Significant_Account

Summary Of Significant Accounting Policies	3 Months Ended
	Mar. 28, 2015
Summary Of Significant Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	NOTE 1.  Summary of Significant Accounting Policies
	Description of business.  PMC-Sierra, Inc. (the “Company” or “PMC”) is a fabless semiconductor and software solution innovator transforming networks that connect, move, and store Big Data. The Company designs, develops, markets and supports semiconductor, embedded software, and board level solutions by integrating its mixed-signal, software and systems expertise through a network of offices in North America, Europe and Asia. Building on a track record of technology leadership, the Company is driving innovation across storage, optical and mobile networks.  PMC’s highly integrated solutions increase performance and enable next generation services to accelerate the network transformation.
	Basis of presentation. The accompanying interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”) and United States Generally Accepted Accounting Principles (“GAAP”).  Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules or regulations.  These interim condensed consolidated financial statements are unaudited, but reflect all adjustments which are normal and recurring in nature and are, in the opinion of management, necessary to provide a fair statement of results for the interim periods presented.  These interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes in the Company’s Annual Report on Form 10-K for the year ended December 27, 2014 filed with the SEC on February 24, 2015.  The results of operations for the interim periods are not necessarily indicative of results to be expected in future periods.  Fiscal 2015 will consist of 52 weeks and will end on Saturday, December 26, 2015.  Fiscal 2014 consisted of 52 weeks and ended on Saturday, December 27, 2014.  The first quarter of each of 2015 and 2014 consisted of 13 weeks.  The Company’s reporting currency is the United States (“U.S.”) dollar and presented in thousands unless otherwise stated.
	Estimates. The preparation of financial statements and related disclosures in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes.  Estimates are used for, but not limited to, stock-based compensation, purchase accounting assumptions including those used to calculate the fair value of intangible assets and goodwill, the valuation of investments, accounting for doubtful accounts, inventory reserves, depreciation and amortization, asset impairments, revenue recognition, sales returns, warranty costs, income taxes including uncertain tax positions, accounting for employee benefit plans, and contingencies.  Actual results could differ materially from these estimates.
	Recent Accounting Pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-03, Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs related to recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts.  This ASU requires retrospective adoption and will be effective for us beginning in our first quarter of 2017.  Early adoption is permitted.  The Company is currently evaluating the effect of the adoption of this ASU on our consolidated financial statements and related disclosures.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, or ASU 2014-09, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in GAAP when it becomes effective.  As currently issued, the new standard is effective for annual periods beginning after December 15, 2016, including interim periods within that reporting period. Early application is not permitted. The standard allows for either full retrospective or modified retrospective adoption method. The Company is currently evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method or determined the effect of the standard on its ongoing financial reporting.

Business_Combinations

Business Combinations	3 Months Ended
	Mar. 28, 2015
Business Combinations [Abstract]
Business Combinations	NOTE 2. Business Combinations
	Acquisition of RAID Software License
	On September 4, 2014 (“Effective Date”), PMC completed a transaction agreement with Hewlett-Packard Company (“HP”) to license core HP Smart Array (“RAID”) software, firmware and management technology (the “Transaction”) for total acquisition consideration of $52 million, accounted for using the acquisition method. With this technology, as well as with certain key employees who worked for HP as lead RAID software development engineers and who were transferred to PMC, PMC can provide more system value to new and existing enterprise, Hyperscale data center and channel customers.
	The $52 million total acquisition consideration is payable in installments.  An initial payment of $10 million was made on the Effective Date and $18 million was paid on January 10, 2015.  The remaining $24 million is payable in two installments of $12 million each on January 10, 2016 and January 10, 2017.  Such installment payments are classified as financing activities in our condensed consolidated statement of cash flows.
	Other Agreement with HP
	Upon the closing of the Transaction, the Company also entered into an agreement with HP related to services and non-recurring engineering (“NRE”) which provides the framework for the development of future generations of RAID software for HP for a period of approximately two years from the Effective Date. During this period, HP will make cost reimbursement payments to the Company totaling $25 million, which are receivable in installments through April 2016. The Company received $3.3 million of the $25 million total cost reimbursement payments from HP in the first quarter of 2015 ($7.3 million since the Effective Date). Payments to the Company in accordance with this agreement are recorded as a reduction of research and development expense.

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 28, 2015
Derivative Instruments [Abstract]
Derivative Instruments	NOTE 3.  Derivative Instruments
	The Company generates revenues in U.S. dollars but incurs a portion of its operating expenses in foreign currencies, primarily the Canadian dollar.  To minimize the short-term impact of foreign currency fluctuations on the Company’s operating expenses, the Company purchases forward currency contracts.  The Company’s accounting policies for these instruments are based on whether the instruments are classified as designated or non-designated hedging instruments. The Company records all derivatives in the Condensed Consolidated Balance Sheets at fair value. The changes in the fair values of the effective portions of designated cash flow hedges are recorded in Accumulated other comprehensive income (loss) until the hedged item is recognized in earnings. Derivatives that are not designated as hedging instruments and the ineffective portion of cash flow hedges are adjusted to fair value through earnings. The Company de-designates its cash flow hedges when the forecasted hedged transactions are realized or it is probable the forecasted hedged transactions will not occur in the initially identified time period. At such time, the associated gains and losses deferred in Accumulated other comprehensive income (loss) are reclassified immediately into earnings and any subsequent changes in the fair value of such derivative instruments are immediately recorded in earnings. The fair value of our derivative instruments are included in prepaid expenses and other assets or accrued liabilities.
	The Company did not recognize any net gains or losses related to the de-designation of discontinued cash flow hedges during the three months ended March 28, 2015.  As at March 28, 2015 the Company had 151 forward currency contracts outstanding (March 29, 2014 - 24), all with maturities of less than 12 months, which qualified and were designated as cash flow hedges.  As of March 28, 2015, the U.S. dollar notional amount of these contracts was $39.2 million (March 29, 2014 - $22.5 million), and the contracts had an aggregate fair value loss of $0.3 million and $0.2 million for the three months ended March 28, 2015 and March 29, 2014, respectively. These were recorded in Accumulated Other Comprehensive Income (Loss), net of taxes of $nil (March 29, 2014 - $0.1 million).

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 28, 2015
Fair Value Measurements [Abstract]
Fair Value Measurements	NOTE 4.  Fair Value Measurements
	ASC Topic 820 specifies a hierarchy of valuation techniques which requires an entity to maximize the use of observable inputs that may be used to measure fair value.  The hierarchy is prioritized into three levels (with Level 3 being the lowest) defined as follows:
	Level 1: Inputs are based on quoted market prices for identical assets and liabilities in active markets at the measurement date.
	Level 2: Inputs include similar quoted prices for similar assets or liabilities; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
	Level 3: Pricing inputs include significant inputs that are generally not observable in the marketplace. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value.
	The Company’s valuation techniques used to measure the fair value of money market funds and other financial instruments were derived from quoted prices in active markets for identical assets. The valuation techniques used to measure the fair value of all other financial instruments, all of which have counterparties with high credit ratings, were valued based on quoted market prices or model driven valuations using significant inputs derived from or corroborated by observable market data.
	In the first quarter of 2015, the Company reviewed and evaluated the observable market pricing data and volume of trading activity used in determining Level 1 and Level 2 assets and classified $13.8 million of investments as Level 2 that were reported as Level 1 at December 27, 2014.  The Company also classified $10.1 million of investments as Level 1 that were reported as Level 2 at December 27, 2014.  The Company’s derivative instruments are classified as Level 2 as of March 28, 2015 and December 27, 2014, as they are not actively traded and are valued using pricing models that use observable market inputs.  There were no Level 3 assets or liabilities at March 28, 2015 or December 27, 2014.
	Assets/Liabilities Measured and Recorded at Fair Value on a Recurring Basis
	Financial assets measured on a recurring basis as at March 28, 2015 and December 27, 2014, are summarized below:
		Fair value,
		28-Mar-15
	(in thousands)	Level 1		Level 2
	Assets:
	Money market funds	$	4,035	$	—
	Corporate bonds and notes		90,114		21,607
	U.S. treasury and government agency notes		40,553		1,946
	Foreign government and agency notes		51		11,130
	U.S. state and municipal securities		—		231
	Total assets	$	134,753	$	34,914
		Fair value,
		27-Dec-14
	(in thousands)	Level 1		Level 2
	Assets:
	Money market funds	$	8,729	$	—
	Corporate bonds and notes		88,401		17,030
	U.S. treasury and government agency notes		38,283		1,387
	Foreign government and agency notes		537		7,525
	U.S. state and municipal securities		—		231
	Total assets	$	135,950	$	26,173
	These assets are included in Cash and cash equivalents, Short-term investments, and Long-term investment securities.  See Note 7. Investment Securities.
	Financial liabilities measured on a recurring basis are summarized below:
		Fair value,
		28-Mar-15
	(in thousands)	Level 2
	Current liabilities:
	Forward currency contracts	$	2,241
		Fair value,
		27-Dec-14
	(in thousands)	Level 2
	Current liabilities:
	Forward currency contracts	$	1,907
	These are included in Accrued liabilities.
	There were no assets or liabilities measured and recorded at fair value on a non-recurring basis as of March 28, 2015 and December 27, 2014.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 28, 2015
Stock-Based Compensation [Abstract]
Stock-Based Compensation	NOTE 5.  Stock-Based Compensation
	The Company has two stock-based compensation plans.  Neither of the Company’s stock-based awards under these plans are classified as liabilities.  The Company recorded stock-based compensation expense for the three months ended March 28, 2015 and March 29, 2014 as follows:
		Three Months Ended
		March 28,		March 29,
	(in thousands)	2015		2014
	Cost of revenues	$	271	$	241
	Research and development		2,844		2,647
	Selling, general and administrative		3,578		3,303
	Total	$	6,693	$	6,191
	The Company received cash of $26.8 million related to the issuance of stock-based awards during the three months ended March 28, 2015 (March 29, 2014 - $9.3 million).
	Equity Award Plans
	The Company issues its equity awards under the provisions of its equity plans. Stock options are granted with an exercise price equal to the closing market price of the Company’s common stock at the grant date. The options generally expire within 10 years and vest over four years.
	Activity under the option plans during the three months ended March 28, 2015 was as follows:
			Number of options	Weighted average exercise price per share			Weighted average remaining contractual term (years)		Aggregate intrinsic value
	Outstanding, December 27, 2014		18,316,720	$	7.53		4.41	$	32,598,999
	Granted		30,000	$	8.88				—
	Exercised		-3,123,174	$	6.82				—
	Forfeited		-3,802	$	6.83				—
	Expired		-282,241	$	10.51				—
	Outstanding, March 28, 2015		14,937,503	$	7.63		4.49	$	27,621,695
	Vested and expected to vest, March 28, 2015		14,753,970	$	7.64		4.43	$	27,155,342
	Exercisable, March 28, 2015		13,222,348	$	7.76		3.97	$	22,969,577
	The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the quoted price of the Company’s common stock for the options that were in-the-money at March 28, 2015.  Total forfeitures recorded amounted to $0.3 million and $0.8 million during the three months ended March 28, 2015, and March 29, 2014, respectively.
	The fair value of the Company’s stock option awards granted to employees is estimated using a lattice-binomial valuation model.  This model considers the contractual term of the option, the probability that the option will be exercised prior to the end of its contractual life, and the probability of termination or retirement of the option holder in computing the value of the option.   The model requires the input of highly subjective assumptions including the expected stock price volatility and expected life.
	The Company’s estimates of expected volatilities are based on a weighted historical and market-based implied volatility.  The Company uses historical data to estimate option exercises and employee terminations within the valuation model; separate groups of employees that have similar historical exercise behavior are considered separately for valuation purposes.  The expected term of options granted is derived from the output of the stock option valuation model and represents the period of time that granted options are expected to be outstanding.  The risk-free rate for periods within the expected life of the stock option is based on the U.S. Treasury yield curve in effect at the time of the grant.
	The fair values of the Company’s stock option awards were calculated for expense recognition using an estimated forfeiture rate, assuming no expected dividends and using the following weighted average assumptions:
			Three Months Ended
			March 28,	March 29,
			2015	2014
	Expected life (years)		5.89	N/A
	Expected volatility		31%	N/A
	Risk-free interest rate		1.6%	N/A
	The weighted average grant-date fair value per stock options granted during the three months ended March 28, 2015 was $2.81.  No stock options were granted during the three months ended March 29, 2014. The total intrinsic value of stock options exercised during the three months ended March 28, 2015 was $7.6 million (March 29, 2014 - $1.2 million).
	As of March 28, 2015, there was $3.0 million of total unrecognized compensation costs related to unvested stock options granted under the plans, which is expected to be recognized over an average period of 2.5 years.
	Restricted Stock Units
	The Company has various stock award plans that allow for the issuance of Restricted Stock Units (“RSUs”) to employees and directors.
	On February 25, 2015, the Company made its annual grant of RSU awards to Executives based on the second performance-based program tied to Non-GAAP operating income targets for 2015-2017. The total fair value of these 2015 grants was estimated at $3.8 million and will be recognized as compensation expense over the award’s vesting terms, with 34% vesting on February 25, 2016, 33% on February 25, 2017 and 33% vesting on February 25, 2018.
	A summary of RSU activity during the three months ended March 28, 2015 is as follows:
			Restricted Stock Units	Weighted Average Remaining Contractual Term (years)			Aggregate intrinsic value
	Unvested units at December 27, 2014		7,368,529		1.73	$	67,200,984
	Awarded		413,108				—
	Released		-190,951				—
	Forfeited		-137,262				—
	Unvested units at March 28, 2015		7,453,424		1.55	$	69,242,309
	Restricted Stock Units expected to vest at March 28, 2015		6,541,680		1.45	$	60,772,202
	The intrinsic value of RSUs vested during the three months ended March 28, 2015 was $1.8 million. As of March 28, 2015, total unrecognized compensation expense, adjusted for estimated forfeitures, related to unvested RSUs was $36.4 million, which is expected to be recognized over the next 2.5 years.
	Employee Stock Purchase Plan
	The 2011 Employee Stock Purchase Plan (the “2011 Plan”) was approved by stockholders at the 2010 Annual Meeting.  The 2011 Plan became effective on February 11, 2011. The 2011 Plan consists of consecutive offering periods, generally of a duration of 6 months, and allows eligible employees to purchase shares of the Company’s common stock at the end of each such offering period, generally February and August of any year, at a price per share equal to 85% of the lower of the fair market value of a share of Common Stock on the start date or the fair market value of a share of Common Stock on the exercise date of the offering period.  Employees purchase such shares through payroll deductions which may not exceed 10% of their total cash compensation.  The 2011 Plan imposes certain limitations upon an employee’s right to acquire Common Stock, including the following: (i) no employee may purchase more than 7,500 shares of Common Stock on any one purchase date and (ii) no employee may be granted rights to purchase more than $25,000 worth of Common Stock for each calendar year that such rights are at any time outstanding.  Up to 12,000,000 shares of our Common Stock have been initially reserved for issuance under the 2011 Plan.
	During the three months ended March 28, 2015, 909,832 shares were issued under the 2011 Plan at a weighted average price of $6.00 per share.  As of March 28, 2015, 3,470,376 shares were available for future issuance under the 2011 Plan compared to 4,380,208 as at December 27, 2014. The valuation inputs utilized to determine the grant date fair value per ESPP award granted were as follows:
			Three Months Ended
			March 28,	March 29,
			2015	2014
	Expected life (years)		0.5	0.5
	Expected volatility		34%	33%
	Risk-free interest rate		0.07%	0.10%
	The weighted average grant date fair value per ESPP award granted during the first three months of 2015 was $2.24.  The total intrinsic value of ESPP shares issued during the first three months of 2015 was $2.8 million.
	As of March 28, 2015, total unrecognized compensation costs, adjusted for estimated forfeitures, related to non-vested ESPP awards was $1.2 million which is expected to be recognized over the next four months.

Balance_Sheet_Items

Balance Sheet Items	3 Months Ended
	Mar. 28, 2015
Balance Sheet Items [Abstract]
Balance Sheet Items	NOTE 6.  Balance Sheet Items
		a.		Inventories.
	Inventories (net of reserves of $7.5 million and $7.8 million at March 28, 2015 and December 27, 2014, respectively) were as follows:
		March 28,			December 27,
	(in thousands)	2015			2014
	Work-in-progress	$	16,838		$	17,438
	Finished goods		18,847			20,511
		$	35,685		$	37,949
		b.		Product warranties.
	The Company provides a limited warranty on most of its standard products and accrues for the estimated cost at the time of shipment.  The Company estimates its warranty costs based on historical failure rates and related repair or replacement costs and periodically reassess these estimates as actual warranty activities occur.  The changes in the Company’s accrued warranty obligations from December 27, 2014 to March 28, 2015, and from December 28, 2013 to March 29, 2014 were as follows:
		Three Months Ended
		March 28,			March 29,
	(in thousands)	2015			2014
	Balance, beginning of the period	$	1,756		$	2,163
	Accrual for new warranties issued		246			124
	Reduction for payments and product replacements		-134			-195
	Adjustments related to revisions and changes in estimate of warranty accrual		—			-88
	Balance, end of the period	$	1,868		$	2,004
	The Company’s accrual for warranty obligations is included in Accrued liabilities in the interim Condensed Consolidated Balance Sheet.

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 28, 2015
Investment Securities [Abstract]
Investment Securities
	NOTE 7.  Investment Securities
	The Company’s available for sale investments, by investment type, consists of the following at March 28, 2015 and December 27, 2014:
		28-Mar-15
	(in thousands)	Amortized Cost		Gross Unrealized Gains*		Gross Unrealized Losses		Fair Value
	Cash equivalents:
	Money market funds	$	4,035		—	$	—	$	4,035
	Total cash equivalents		4,035		—		—		4,035
	Short-term investments:
	Corporate bonds and notes		42,724		469		-3		43,190
	US treasury and government agency notes		1,520		86		—		1,606
	Foreign government and agency notes		500		53		—		553
	US states and municipal securities		230		1		—		231
	Total short-term investments		44,974		609		-3		45,580
	Long-term investment securities:
	Corporate bonds and notes		68,434		132		-35		68,531
	US treasury and government agency notes		40,815		86		-8		40,893
	Foreign government and agency notes		10,632		4		-8		10,628
	Total long-term investment securities		119,881		222		-51		120,052
	Total	$	168,890	$	831	$	-54	$	169,667
	*Gross unrealized gains include accrued interest on investments of $0.6 million which are included in the Consolidated Statement of Operations.  The remainder of the gross unrealized gains and losses are included in the Consolidated Balance Sheet as Accumulated other comprehensive income (loss).
		27-Dec-14
	(in thousands)	Amortized Cost		Gross Unrealized Gains*		Gross Unrealized Losses		Fair Value
	Cash equivalents:
	Money market funds	$	8,729	$	—	$	—	$	8,729
	Total cash equivalents		8,729		—		—		8,729
	Short-term investments:
	Corporate bonds and notes		43,777		498		-16		44,259
	US treasury and government agency notes		1,010		79		—		1,089
	Foreign government and agency notes		501		36		—		537
	Total short-term investments		45,288		613		-16		45,885
	Long-term investment securities:
	Corporate bonds and notes		61,357		28		-213		61,172
	US treasury and government agency notes		38,650		7		-76		38,581
	Foreign government and agency notes		7,563		1		-39		7,525
	US states and municipal securities		230		1		—		231
	Total long-term investment securities		107,800		37		-328		107,509
	Total	$	161,817	$	650	$	-344	$	162,123
	*Gross unrealized gains include accrued interest on investments of $0.6 million which are included in the Consolidated Statement of Operations.  The remainder of the gross unrealized gains and losses are included in the Consolidated Balance Sheet as Accumulated other comprehensive income (loss).
	As of March 28, 2015 and December 27, 2014, the fair value of certain of the Company’s available-for-sale securities was less than their cost basis.  Management reviews various factors in determining whether to recognize an impairment charge related to these unrealized losses, including the current financial and credit market environment, the financial condition, near-term prospects of the issuer of the investment security, the magnitude of the unrealized loss compared to the cost of the investment, length of time the investment has been in a loss position and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery of market value.  As of March 28, 2015, the Company determined that all the unrealized losses are temporary in nature and recorded them as a component of Accumulated other comprehensive income (loss).
	Contractual maturities as of March 28, 2015 of the Company’s investment securities do not exceed three years.  The majority of the contractual maturities are two to three years, and the balance has maturities of one year or less.

Credit_Facility

Credit Facility	3 Months Ended
	Mar. 28, 2015
Credit Facility [Abstract]
Credit Facility	NOTE 8. Credit Facility
	As of March 28, 2015, the Company had an available revolving line of credit with a bank under which the Company may borrow up to $100 million, of which $10 million was drawn (December 27, 2014 - $nil). The Company may request, from time to time, and subject to customary conditions, including receipt of commitments, that the revolving credit facility be increased by an aggregate amount not to exceed $150 million.  Interest payments are based on LIBOR plus margins, where margins ranges from 1.75% to 2.25% per annum based on the Company’s leverage ratio.  The revolving credit facility is available for general corporate purposes. The credit facility is collateralized by substantially all of the Company’s personal property. The Company’s obligations under the credit facility are jointly and severally guaranteed by material wholly-owned domestic subsidiaries of the Company.
	On April 27, 2015, the Company repaid the $10 million outstanding balance as of March 28, 2015.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 28, 2015
Income Taxes [Abstract]
Income Taxes	NOTE 9.  Income Taxes
	The Company recorded a provision for income taxes of $2.7 million and $1.8 million for the three months ended March 28, 2015 and March 29, 2014, respectively.
	The Company’s effective tax rate was 37% and (77%) for the three months ended March 28, 2015 and March 29, 2014, respectively.  For each of the first quarters of 2015 and 2014, the difference between the Company’s effective tax rate and the 35% federal statutory rate results primarily from changes in accruals related to unrecognized tax benefits and non-deductible amortization of intangible assets, partially offset by foreign earnings eligible for tax rates lower than the federal statutory rate.  In addition, for the three months ended March 29, 2014, the Company’s tax rate was negative due to a recorded tax expense on pretax loss.
	As of March 28, 2015 and December 27, 2014, the Company’s liability for unrecognized tax benefits on a world-wide consolidated basis was $40.6 million and $41.3 million, respectively. The ultimate recognition of an amount different from this estimate would affect the Company’s effective tax rate.

Net_Income_Loss_Per_Share

Net Income (Loss) Per Share	3 Months Ended
	Mar. 28, 2015
Net Income (Loss) Per Share [Abstract]
Net Income (Loss) Per Share	NOTE 10.  Net Income (Loss) Per Share
	The following table sets forth the computation of basic and diluted net income (loss) per share:
		Three Months Ended
		March 28,			March 29,
	(in thousands, except per share amounts)	2015			2014
	Numerator:
	Net income (loss)	$	4,655		$	-4,241
	Denominator:
	Basic weighted average common shares outstanding (1)		200,249			195,188
	Dilutive effect of employee stock options and awards		5,439			—
	Diluted weighted average common shares outstanding (1)		205,688			195,188
	Basic and diluted net income (loss) per share	$	0.02		$	-0.02
		-1		PMC-Sierra Ltd. special shares are included in the calculation of basic and diluted weighted average common shares outstanding.
	In the three months ended March 29, 2014, the Company had approximately 3.1 million of stock options and Restricted Stock Units that were not included in the diluted net loss per share because they would have been anti-dilutive.

Stock_Repurchase_Program

Stock Repurchase Program	3 Months Ended
	Mar. 28, 2015
Stock Repurchase Program [Abstract]
Stock Repurchase Program	NOTE 11.  Stock Repurchase Program
	On February 9, 2015, the Board of Directors of the Company authorized a new share repurchase program for up to $75 million of its common stock.  This new program increased the total remaining repurchase authorization to $102.1 million, including the $27.1 million that remained available for repurchases under the $275 million 2012 share repurchase authorization as of December 27, 2014. For the three months ended March 28, 2015 and March 29, 2014, the Company repurchased 6.1 million and 1.4 million shares for a total cash cost of $57.2 million and $8.9 million, respectively. The repurchased shares were retired immediately.  Accordingly, the repurchased shares were recorded as a reduction of common stock, additional paid-in capital and accumulated deficit.  As of March 28, 2015, the Company had completed $385.1 million of the total announced $430.0 million stock repurchase programs since 2011.

Summary_Of_Significant_Account1

Summary Of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 28, 2015
Summary Of Significant Accounting Policies [Abstract]
Description Of Business	Description of business.  PMC-Sierra, Inc. (the “Company” or “PMC”) is a fabless semiconductor and software solution innovator transforming networks that connect, move, and store Big Data. The Company designs, develops, markets and supports semiconductor, embedded software, and board level solutions by integrating its mixed-signal, software and systems expertise through a network of offices in North America, Europe and Asia. Building on a track record of technology leadership, the Company is driving innovation across storage, optical and mobile networks.  PMC’s highly integrated solutions increase performance and enable next generation services to accelerate the network transformation.
Basis Of Presentation	Basis of presentation. The accompanying interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”) and United States Generally Accepted Accounting Principles (“GAAP”).  Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules or regulations.  These interim condensed consolidated financial statements are unaudited, but reflect all adjustments which are normal and recurring in nature and are, in the opinion of management, necessary to provide a fair statement of results for the interim periods presented.  These interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes in the Company’s Annual Report on Form 10-K for the year ended December 27, 2014 filed with the SEC on February 24, 2015.  The results of operations for the interim periods are not necessarily indicative of results to be expected in future periods.  Fiscal 2015 will consist of 52 weeks and will end on Saturday, December 26, 2015.  Fiscal 2014 consisted of 52 weeks and ended on Saturday, December 27, 2014.  The first quarter of each of 2015 and 2014 consisted of 13 weeks.  The Company’s reporting currency is the United States (“U.S.”) dollar and presented in thousands unless otherwise stated.
Estimates	Estimates. The preparation of financial statements and related disclosures in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes.  Estimates are used for, but not limited to, stock-based compensation, purchase accounting assumptions including those used to calculate the fair value of intangible assets and goodwill, the valuation of investments, accounting for doubtful accounts, inventory reserves, depreciation and amortization, asset impairments, revenue recognition, sales returns, warranty costs, income taxes including uncertain tax positions, accounting for employee benefit plans, and contingencies.  Actual results could differ materially from these estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-03, Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs related to recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts.  This ASU requires retrospective adoption and will be effective for us beginning in our first quarter of 2017.  Early adoption is permitted.  The Company is currently evaluating the effect of the adoption of this ASU on our consolidated financial statements and related disclosures.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, or ASU 2014-09, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in GAAP when it becomes effective.  As currently issued, the new standard is effective for annual periods beginning after December 15, 2016, including interim periods within that reporting period. Early application is not permitted. The standard allows for either full retrospective or modified retrospective adoption method. The Company is currently evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method or determined the effect of the standard on its ongoing financial reporting.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 28, 2015
Fair Value Measurements [Abstract]
Financial Assets Measured At Fair Value On Recurring Basis
		Fair value,
		28-Mar-15
	(in thousands)	Level 1		Level 2
	Assets:
	Money market funds	$	4,035	$	—
	Corporate bonds and notes		90,114		21,607
	U.S. treasury and government agency notes		40,553		1,946
	Foreign government and agency notes		51		11,130
	U.S. state and municipal securities		—		231
	Total assets	$	134,753	$	34,914
		Fair value,
		27-Dec-14
	(in thousands)	Level 1		Level 2
	Assets:
	Money market funds	$	8,729	$	—
	Corporate bonds and notes		88,401		17,030
	U.S. treasury and government agency notes		38,283		1,387
	Foreign government and agency notes		537		7,525
	U.S. state and municipal securities		—		231
	Total assets	$	135,950	$	26,173
	These assets are included in Cash and cash equivalents, Short-term investments, and Long-term investment securities.  See Note 7. Investment Securities.
Liabilities Measured At Fair Value On A Recurring Basis
		Fair value,
		28-Mar-15
	(in thousands)	Level 2
	Current liabilities:
	Forward currency contracts	$	2,241
		Fair value,
		27-Dec-14
	(in thousands)	Level 2
	Current liabilities:
	Forward currency contracts	$	1,907
	These are included in Accrued liabilities.

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule Of Stock-Based Compensation Expense
		Three Months Ended
		March 28,		March 29,
	(in thousands)	2015		2014
	Cost of revenues	$	271	$	241
	Research and development		2,844		2,647
	Selling, general and administrative		3,578		3,303
	Total	$	6,693	$	6,191
Schedule Of Activity Under Option Plans
			Number of options	Weighted average exercise price per share			Weighted average remaining contractual term (years)		Aggregate intrinsic value
	Outstanding, December 27, 2014		18,316,720	$	7.53		4.41	$	32,598,999
	Granted		30,000	$	8.88				—
	Exercised		-3,123,174	$	6.82				—
	Forfeited		-3,802	$	6.83				—
	Expired		-282,241	$	10.51				—
	Outstanding, March 28, 2015		14,937,503	$	7.63		4.49	$	27,621,695
	Vested and expected to vest, March 28, 2015		14,753,970	$	7.64		4.43	$	27,155,342
	Exercisable, March 28, 2015		13,222,348	$	7.76		3.97	$	22,969,577
Schedule Of Fair Value Assumptions
			Three Months Ended
			March 28,	March 29,
			2015	2014
	Expected life (years)		5.89	N/A
	Expected volatility		31%	N/A
	Risk-free interest rate		1.6%	N/A
Schedule Of Summary Of RSU Activity
			Restricted Stock Units	Weighted Average Remaining Contractual Term (years)			Aggregate intrinsic value
	Unvested units at December 27, 2014		7,368,529		1.73	$	67,200,984
	Awarded		413,108				—
	Released		-190,951				—
	Forfeited		-137,262				—
	Unvested units at March 28, 2015		7,453,424		1.55	$	69,242,309
	Restricted Stock Units expected to vest at March 28, 2015		6,541,680		1.45	$	60,772,202
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule Of Fair Value Assumptions
			Three Months Ended
			March 28,	March 29,
			2015	2014
	Expected life (years)		0.5	0.5
	Expected volatility		34%	33%
	Risk-free interest rate		0.07%	0.10%

Balance_Sheet_Items_Tables

Balance Sheet Items (Tables)	3 Months Ended
	Mar. 28, 2015
Balance Sheet Items [Abstract]
Schedule Of Inventory
		March 28,		December 27,
	(in thousands)	2015		2014
	Work-in-progress	$	16,838	$	17,438
	Finished goods		18,847		20,511
		$	35,685	$	37,949
Schedule Of Product Warranties
		Three Months Ended
		March 28,		March 29,
	(in thousands)	2015		2014
	Balance, beginning of the period	$	1,756	$	2,163
	Accrual for new warranties issued		246		124
	Reduction for payments and product replacements		-134		-195
	Adjustments related to revisions and changes in estimate of warranty accrual		—		-88
	Balance, end of the period	$	1,868	$	2,004

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 28, 2015
Investment Securities [Abstract]
Available For Sale Investments
		28-Mar-15
	(in thousands)	Amortized Cost		Gross Unrealized Gains*		Gross Unrealized Losses		Fair Value
	Cash equivalents:
	Money market funds	$	4,035		—	$	—	$	4,035
	Total cash equivalents		4,035		—		—		4,035
	Short-term investments:
	Corporate bonds and notes		42,724		469		-3		43,190
	US treasury and government agency notes		1,520		86		—		1,606
	Foreign government and agency notes		500		53		—		553
	US states and municipal securities		230		1		—		231
	Total short-term investments		44,974		609		-3		45,580
	Long-term investment securities:
	Corporate bonds and notes		68,434		132		-35		68,531
	US treasury and government agency notes		40,815		86		-8		40,893
	Foreign government and agency notes		10,632		4		-8		10,628
	Total long-term investment securities		119,881		222		-51		120,052
	Total	$	168,890	$	831	$	-54	$	169,667
	*Gross unrealized gains include accrued interest on investments of $0.6 million which are included in the Consolidated Statement of Operations.  The remainder of the gross unrealized gains and losses are included in the Consolidated Balance Sheet as Accumulated other comprehensive income (loss).
		27-Dec-14
	(in thousands)	Amortized Cost		Gross Unrealized Gains*		Gross Unrealized Losses		Fair Value
	Cash equivalents:
	Money market funds	$	8,729	$	—	$	—	$	8,729
	Total cash equivalents		8,729		—		—		8,729
	Short-term investments:
	Corporate bonds and notes		43,777		498		-16		44,259
	US treasury and government agency notes		1,010		79		—		1,089
	Foreign government and agency notes		501		36		—		537
	Total short-term investments		45,288		613		-16		45,885
	Long-term investment securities:
	Corporate bonds and notes		61,357		28		-213		61,172
	US treasury and government agency notes		38,650		7		-76		38,581
	Foreign government and agency notes		7,563		1		-39		7,525
	US states and municipal securities		230		1		—		231
	Total long-term investment securities		107,800		37		-328		107,509
	Total	$	161,817	$	650	$	-344	$	162,123
	*Gross unrealized gains include accrued interest on investments of $0.6 million which are included in the Consolidated Statement of Operations.  The remainder of the gross unrealized gains and losses are included in the Consolidated Balance Sheet as Accumulated other comprehensive income (loss).

Net_Income_Loss_Per_Share_Tabl

Net Income (Loss) Per Share (Tables)	3 Months Ended
	Mar. 28, 2015
Net Income (Loss) Per Share [Abstract]
Schedule Of Net Loss Per Share
		Three Months Ended
		March 28,			March 29,
	(in thousands, except per share amounts)	2015			2014
	Numerator:
	Net income (loss)	$	4,655		$	-4,241
	Denominator:
	Basic weighted average common shares outstanding (1)		200,249			195,188
	Dilutive effect of employee stock options and awards		5,439			—
	Diluted weighted average common shares outstanding (1)		205,688			195,188
	Basic and diluted net income (loss) per share	$	0.02		$	-0.02
		-1		PMC-Sierra Ltd. special shares are included in the calculation of basic and diluted weighted average common shares outstanding.

Business_Combinations_Details

Business Combinations (Details) (USD $)	0 Months Ended	3 Months Ended	0 Months Ended	7 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Sep. 04, 2014	Mar. 28, 2015	Jan. 10, 2015	Mar. 28, 2015	Jan. 10, 2017	Jan. 10, 2016
Business Acquisition [Line Items]
Total acquisition consideration	$52
Amount of consideration transferred remaining		24
Reimbursement Revenue		3.3
Cost reimbursement payments		25		25
RAID Software [Member]
Business Acquisition [Line Items]
Installment payment	10		18
Reimbursement Revenue				7.3
Forecast [Member] | RAID Software [Member]
Business Acquisition [Line Items]
Installment payment					$12	$12

Derivative_Instruments_Details

Derivative Instruments (Details) (Cash Flow Hedging [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
	contract	contract
Cash Flow Hedging [Member]
Derivative [Line Items]
Forward currency contracts outstanding	151	24
Forward currency contracts maturity, maximum	12 months
Notional amount of contracts	$39.20	$22.50
Fair value loss, net of taxes	0.3	0.2
Tax effect on fair value gain		$0.10

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	Mar. 28, 2015	Dec. 27, 2014
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured and recorded at fair value	$0	$0
Liabilities measured and recorded at fair value	0	0
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments previously listed as Level 2	10,100,000
Assets measured and recorded at fair value	134,753,000	135,950,000
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments previously listed as Level 1	13,800,000
Assets measured and recorded at fair value	34,914,000	26,173,000
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured and recorded at fair value	0
Liabilities measured and recorded at fair value	$0

Fair_Value_Measurements_Financ

Fair Value Measurements (Financial Assets Measured At Fair Values On Recurring Basis) (Details) (USD $)	Mar. 28, 2015	Dec. 27, 2014
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$134,753,000	$135,950,000
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	4,035,000	8,729,000
Level 1 [Member] | Corporate Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	90,114,000	88,401,000
Level 1 [Member] | United States ("US") Treasury And Government Agency Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	40,553,000	38,283,000
Level 1 [Member] | Foreign Government And Agency Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	51,000	537,000
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	34,914,000	26,173,000
Level 2 [Member] | Corporate Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	21,607,000	17,030,000
Level 2 [Member] | United States ("US") Treasury And Government Agency Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	1,946,000	1,387,000
Level 2 [Member] | Foreign Government And Agency Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	11,130,000	7,525,000
Level 2 [Member] | US State And Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$231,000	$231,000

Fair_Value_Measurements_Liabil

Fair Value Measurements (Liabilities Measured At Fair Value On A Recurring Basis) (Details) (Level 2 [Member], USD $)	Mar. 28, 2015	Dec. 27, 2014
In Thousands, unless otherwise specified
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward currency contracts	$2,241	$1,907

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
	ShareBasedCompensationPlan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation programs	2
Proceeds from issuance of stock-based awards	$26,800,000	$9,300,000
Weighted average grant-date fair value per stock option	$2.81
Stock options granted		0
Total intrinsic value of stock options	7,600,000	1,200,000
Total unrecognized compensation costs	3,000,000
Unrecognized compensation expected to be recognized, average period	2 years 6 months
Total intrinsic value of ESPP shares issued	2,800,000
Total forfeitures recorded	300,000	800,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of stock options	1,800,000
Total unrecognized compensation costs	36,400,000
Unrecognized compensation expected to be recognized, average period	2 years 6 months
Fair value of grants	3,800,000
Restricted Stock Units (RSUs) [Member] | February 25, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	34.00%
Restricted Stock Units (RSUs) [Member] | February 25, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.00%
Restricted Stock Units (RSUs) [Member] | February 25, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.00%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs	1,200,000
Weighted average grant-date fair value per ESPP award	$2.24
2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period (years)	10 years
Award vesting period (years)	4 years
2011 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance	3,470,376		4,380,208
Shares issued	909,832
Stock price as a percentage of fair value	85.00%
Maximum percentage of compensation an employee can use to purchase stock	10.00%
Weighted average price per share under ESPP	$6
Maximum [Member] | 2011 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance	12,000,000
Maximum shares of stock an employee can purchase	7,500
Maximum amount granted to each employee to purchase common stock under ESPP	$25,000

StockBased_Compensation_Schedu

Stock-Based Compensation (Schedule Of Stock-Based Compensation Expense) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$6,693	$6,191
Cost of revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	271	241
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,844	2,647
Selling, general and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$3,578	$3,303

StockBased_Compensation_Schedu1

Stock-Based Compensation (Schedule Of Activity Under Option Plans) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 28, 2015	Dec. 27, 2014
Stock-Based Compensation [Abstract]
Outstanding beginning balance, Number of options	18,316,720
Granted and Assumed, Number of options	30,000
Exercised, Number of options	-3,123,174
Forfeited, Number of options	-3,802
Expired, Number of options	-282,241
Outstanding ending balance, Number of options	14,937,503	18,316,720
Vested & expected to vest, Number of options	14,753,970
Exercisable ending balance, Number of options	13,222,348
Outstanding beginning balance, Weighted average exercise price per share	$7.53
Granted and Assumed, Weighted average exercise price per share	$8.88
Exercised, Weighted average exercise price per share	$6.82
Forfeited, Weighted average exercise price per share	$6.83
Expired, Weighted average exercise price per shre	$10.51
Outstanding ending balance, Weighted average exercise price per share	$7.63	$7.53
Vested & expected to vest, Weighted average exercise price per share	$7.64
Exercisable ending balance, Weighted average exercise price per share	$7.76
Outstanding ending balance, Weighted average remaining contractual term (years)	4 years 5 months 27 days	4 years 4 months 28 days
Vested & expected to vest, Weighted average remaining contractual term (years)	4 years 5 months 5 days
Exercisable ending balance, Weighted average remaining contractual term (years)	3 years 11 months 19 days
Outstanding beginning balance, Aggregate intrinsic value	$32,598,999
Outstanding ending balance, Aggregate intrinsic value	27,621,695	32,598,999
Vested & expected to vest, Aggregate intrinsic value	27,155,342
Exercisable ending balance, Aggregate intrinsic value	$22,969,577

StockBased_Compensation_Schedu2

Stock-Based Compensation (Schedule Of Fair Values Of Company's Stock Option Awards) (Details)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	5 years 10 months 21 days
Expected volatility	31.00%
Risk-free interest rate	1.60%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	6 months	6 months
Expected volatility	34.00%	33.00%
Risk-free interest rate	0.07%	0.10%

StockBased_Compensation_Schedu3

Stock-Based Compensation (Schedule Of Summary Of RSU Activity) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 28, 2015	Dec. 27, 2014
Stock-Based Compensation [Abstract]
Beginning of period, Unvested Restricted Stock Units	7,368,529
Awarded, Restricted Stock Units	413,108
Released, Restricted Stock Units	-190,951
Forfeited, Restricted Stock Units	-137,262
End of period, Restricted Stock Units	7,453,424	7,368,529
Restricted Stock Units expected to vest	6,541,680
Weighted Average Remaining Contractual Term (years)	1 year 6 months 18 days	1 year 8 months 23 days
Restricted Stock Units expected to vest, Weighted Average Remaining Contractual Term (years)	1 year 5 months 12 days
Beginning of period, Aggregate intrinsic value	$67,200,984
End of period, Aggregate intrinsic value	69,242,309	67,200,984
Restricted Stock Units expected to vest, Aggregate intrinsic value	$60,772,202

Balance_Sheet_Items_Schedule_O

Balance Sheet Items (Schedule Of Inventory) (Details) (USD $)	Mar. 28, 2015	Dec. 27, 2014
Balance Sheet Items [Abstract]
Work-in-progress	$16,838,000	$17,438,000
Finished goods	18,847,000	20,511,000
Inventory, net	35,685,000	37,949,000
Inventory reserves	$7,500,000	$7,800,000

Balance_Sheet_Items_Schedule_O1

Balance Sheet Items (Schedule Of Product Warranties) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Balance Sheet Items [Abstract]
Balance, beginning of the period	$1,756	$2,163
Accrual for new warranties issued	246	124
Reduction for payments and product replacements	-134	-195
Adjustments related to provisions and changes in estimate of warranty accrual		-88
Balance, end of the period	$1,868	$2,004

Investment_Securities_Narrativ

Investment Securities (Narrative) (Details)	3 Months Ended
	Mar. 28, 2015
Schedule of Investments [Line Items]
Contractual maturities of investment securities	3 years
Minimum [Member]
Schedule of Investments [Line Items]
Contractual maturities of investment securities	2 years
Maximum [Member]
Schedule of Investments [Line Items]
Contractual maturities of investment securities	3 years
Contractual maturities of investment securities, balance	1 year

Investment_Securities_Availabl

Investment Securities (Available For Sale Investments) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 28, 2015	Dec. 27, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$168,890,000	$161,817,000
Gross Unrealized Gains	831,000	650,000
Gross Unrealized Losses	-54,000	-344,000
Fair Value	169,667,000	162,123,000
Accrued interest on investments	600,000	600,000
Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,035,000	8,729,000
Fair Value	4,035,000	8,729,000
Cash Equivalents [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,035,000	8,729,000
Fair Value	4,035,000	8,729,000
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	44,974,000	45,288,000
Gross Unrealized Gains	609,000	613,000
Gross Unrealized Losses	-3,000	-16,000
Fair Value	45,580,000	45,885,000
Short-Term Investments [Member] | Corporate Bonds And Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	42,724,000	43,777,000
Gross Unrealized Gains	469,000	498,000
Gross Unrealized Losses	-3,000	-16,000
Fair Value	43,190,000	44,259,000
Short-Term Investments [Member] | US Treasury And Government Agency Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,520,000	1,010,000
Gross Unrealized Gains	86,000	79,000
Fair Value	1,606,000	1,089,000
Short-Term Investments [Member] | Foreign Government And Agency Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	500,000	501,000
Gross Unrealized Gains	53,000	36,000
Fair Value	553,000	537,000
Short-Term Investments [Member] | US States And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	230,000
Gross Unrealized Gains	1,000
Fair Value	231,000
Long-Term Investment Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	119,881,000	107,800,000
Gross Unrealized Gains	222,000	37,000
Gross Unrealized Losses	-51,000	-328,000
Fair Value	120,052,000	107,509,000
Long-Term Investment Securities [Member] | Corporate Bonds And Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68,434,000	61,357,000
Gross Unrealized Gains	132,000	28,000
Gross Unrealized Losses	-35,000	-213,000
Fair Value	68,531,000	61,172,000
Long-Term Investment Securities [Member] | US Treasury And Government Agency Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	40,815,000	38,650,000
Gross Unrealized Gains	86,000	7,000
Gross Unrealized Losses	-8,000	-76,000
Fair Value	40,893,000	38,581,000
Long-Term Investment Securities [Member] | Foreign Government And Agency Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,632,000	7,563,000
Gross Unrealized Gains	4,000	1,000
Gross Unrealized Losses	-8,000	-39,000
Fair Value	10,628,000	7,525,000
Long-Term Investment Securities [Member] | US States And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		230,000
Gross Unrealized Gains		1,000
Fair Value		$231,000

Credit_Facility_Details

Credit Facility (Details) (USD $)	1 Months Ended
	Apr. 27, 2015	Mar. 28, 2015	Dec. 27, 2014
Line of Credit Facility [Line Items]
Line of credit, amount drawn		$10,000,000	$0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility line of credit		100,000,000
Repayment of amount outstanding	10,000,000
Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Margin rates		1.75%
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility line of credit		$150,000,000
Margin rates		2.25%

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Income Taxes [Abstract]
Provision for income taxes	$2,731,000	$1,847,000
Effective tax rate	37.00%	-77.00%
Federal statutory rate	35.00%	35.00%
Unrecognized tax benefits	$40,600,000		$41,300,000

Net_Income_Loss_Per_Share_Deta

Net Income (Loss) Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015		Mar. 29, 2014
Net Income (Loss) Per Share [Abstract]
Net income (loss)	$4,655		($4,241)
Basic and diluted weighted average common shares outstanding	200,249	[1]	195,188	[1]
Dilutive effect of employee stock options and awards	5,439
Diluted weighted average common shares outstanding	205,688	[1]	195,188	[1]
Basic and diluted net income (loss) per share	$0.02		($0.02)
Antidilutive securities excluded from computation of earnings per share			3,100,000
[1]	PMC-Sierra Ltd. special shares are included in the calculation of basic and diluted weighted average common shares outstanding.

Stock_Repurchase_Program_Detai

Stock Repurchase Program (Details) (USD $)	0 Months Ended	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Feb. 09, 2015	Mar. 28, 2015	Mar. 29, 2014	Dec. 27, 2014
Equity, Class of Treasury Stock [Line Items]
Share repurchase plan, authorized amount	$75	$430
Stock repurchased of common stock, shares		6.1	1.4
Share repurchase plan, authorized amount available	102.1	385.1
Shares repurchased and retired, value		57.2	8.9
2012 Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase plan, authorized amount				275
Share repurchase plan, authorized amount available	$27.10