Thoratec 10-Q 7 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
In Millions, unless otherwise specified	Mar. 29, 2014	Apr. 25, 2014
Document and Entity Information	'	'
Entity Registrant Name	'THORATEC CORP	'
Entity Central Index Key	'0000350907	'
Document Type	'10-Q	'
Document Period End Date	29-Mar-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-28	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	56.8
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 29, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$108,653	$139,099
Short-term available-for-sale investments	186,535	166,691
Receivables, net of allowances of $2,396 in 2014 and $2,163 in 2013	77,220	71,418
Inventories	59,345	60,293
Deferred tax assets	15,161	15,161
Income tax receivable	9,781	5,733
Prepaid expenses and other assets	8,196	7,272
Total current assets	464,891	465,667
Property, plant and equipment, net	55,084	55,163
Goodwill	207,026	205,764
Purchased intangible assets, net	34,593	36,403
Long-term available-for-sale investments	4,247	4,234
Other long-term assets	23,301	24,476
Total Assets	789,142	791,707
Current liabilities:	'	'
Accounts payable	15,923	17,599
Accrued compensation	17,942	22,759
Contingent liabilities, current portion	9,189	6,962
Other accrued liabilities	29,989	27,001
Total current liabilities	73,043	74,321
Long-term deferred tax liability	1,876	2,224
Other long-term liabilities	12,317	12,105
Contingent liabilities, non-current portion (Note 2)	26,728	36,384
Total Liabilities	113,964	125,034
Shareholders' equity:	'	'
Common shares: no par, authorized 100,000; issued and outstanding 56,885 in 2014 and 56,904 in 2013	'	'
Additional paid-in-capital	625,085	621,589
Retained earnings	62,548	57,587
Accumulated other comprehensive loss:	-12,455	-12,503
Total Shareholders' Equity	675,178	666,673
Total Liabilities and Shareholders' Equity	$789,142	$791,707

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 29, 2014	Dec. 28, 2013
In Thousands, except Per Share data, unless otherwise specified
CONDENSED CONSOLIDATED BALANCE SHEETS	'	'
Receivables, allowances (in dollars)	$2,396	$2,163
Common shares, par value (in dollars per share)	$0	$0
Common shares, authorized	100,000	100,000
Common shares, issued	56,885	56,904
Common shares, outstanding	56,885	56,904

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS	'	'
Product sales	$125,697	$117,725
Cost of product sales	40,026	35,073
Gross profit	85,671	82,652
Operating expenses:	'	'
Selling, general and administrative	35,501	34,745
Research and development	23,339	24,513
Total operating expenses	58,840	59,258
Income from operations	26,831	23,394
Other income and (expense):	'	'
Interest expense and other	'	-4
Interest income and other	247	1,117
Income before income taxes	27,078	24,507
Income tax expense	8,839	6,337
Net income	$18,239	$18,170
Net Income per share:	'	'
Basic (in dollars per share)	$0.32	$0.32
Diluted (in dollars per share)	$0.32	$0.31
Shares used to compute net income per share:	'	'
Basic (in shares)	56,840	57,486
Diluted (in shares)	57,666	58,507

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	'	'
Net Income	$18,239	$18,170
Unrealized gains (losses) on investments (net of taxes of $(286) and $146 for the three months ended March 29, 2014 and March 30, 2013, respectively)	-1,411	218
Foreign currency translation adjustments	1,459	-2,288
Total other comprehensive income (loss)	48	-2,070
Comprehensive Income	$18,287	$16,100

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	'	'
Unrealized gains (losses) on investments, taxes	($286)	$146

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
Cash flows from operating activities:	'	'
Net Income	$18,239	$18,170
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	4,163	4,495
Investment premium amortization, net	1,045	821
Allowance for (reduction in) bad debt	-599	8
Non-cash interest income and other	405	380
Change in fair value of contingent consideration	-467	'
Tax benefit related to stock options	875	1,293
Share-based compensation expense	6,782	6,167
Excess tax benefits from share-based compensation	-898	-1,271
Loss (gain) on disposal of assets	-41	57
Change in net deferred tax liability	-207	-737
Changes in assets and liabilities:	'	'
Receivables	-5,026	2,781
Inventories	507	-11,071
Other current and non-current assets	-316	-261
Accounts payable	-1,030	3,865
Income taxes, net	-2,458	-1,913
Other current and non-current liabilities	-3,545	-9,288
Net cash provided by operating activities	17,429	13,496
Cash flows from investing activities:	'	'
Purchases of available-for-sale investments	-71,436	-48,708
Sales and maturities of available-for-sale investments	50,011	36,243
Purchases of property, plant and equipment	-2,157	-3,883
Net cash used in investing activities	-23,582	-16,348
Cash flows from financing activities:	'	'
Payment of contingent consideration	-6,107	-4,220
Proceeds from stock option exercises	2,653	2,512
Excess tax benefits from share-based compensation	898	1,271
Repurchase and retirement of common shares	-22,285	-5,802
Net cash used in financing activities	-24,841	-6,239
Effect of exchange rate changes on cash and cash equivalents	548	-772
Net decrease in cash and cash equivalents	-30,446	-9,863
Net cash and cash equivalents at beginning of period	139,099	101,322
Net cash and cash equivalents at end of period	108,653	91,459
Supplemental disclosure of consolidated cash flow information:	'	'
Cash paid for income taxes	10,801	7,660
Supplemental disclosure of consolidated non-cash investing and financing activities:	'	'
Transfers of equipment from inventory	650	594
Repurchases and retirement of common shares through other accrued liabilities	625	'
Purchases of property, plant and equipment through accounts payable and accrued liabilities	$410	$445

Operations_and_Significant_Acc

Operations and Significant Accounting Policies	3 Months Ended
	Mar. 29, 2014
Operations and Significant Accounting Policies	'
Operations and Significant Accounting Policies	'
	Note 1. Operations and Significant Accounting Policies
	Basis of Presentation
	The interim unaudited condensed consolidated financial statements of Thoratec Corporation (“we,” “our,” “us,” or the “Company”) have been prepared and presented in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”), without audit, and reflect all adjustments necessary (consisting only of normal recurring adjustments) to present fairly our financial position, results of operations and cash flows as of and for the periods presented. Certain information and footnote disclosures normally included in our annual financial statements, prepared in accordance with GAAP, have been condensed or omitted. The accompanying financial statements should be read in conjunction with our fiscal 2013 consolidated financial statements, and the accompanying notes thereto, filed with the SEC in our 2013 Annual Report on Form 10-K for the fiscal year ended December 28, 2013 (the “2013 Annual Report”). The operating results for any interim period are not necessarily indicative of the results that may be expected for any future period.
	The preparation of our unaudited condensed consolidated financial statements necessarily requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities on the unaudited condensed consolidated balance sheet dates and the reported amounts of revenues and expenses for the periods presented. The actual amounts could differ from those estimated amounts.

Acquisition_of_DuraHeart_II

Acquisition of DuraHeart II	3 Months Ended
	Mar. 29, 2014
Acquisition of DuraHeart II	'
Acquisition of DuraHeart II	'
	Note 2. Acquisition of DuraHeart II
	On June 30, 2013 (“acquisition date”), we acquired certain assets (the “Purchased Assets”) and assumed certain liabilities from Terumo Corporation (“Terumo”) related to the DuraHeart II Left Ventricular Assist System product line (“DuraHeart II”) previously under development by Terumo. Under the terms of the acquisition, we made an upfront cash payment to Terumo of $13.0 million, and will be obligated to make potential future milestone payments, based on regulatory approvals and product sales, of up to $43.5 million. Terumo also maintains the right to repurchase the Purchased Assets in the event that we do not fulfill certain conditions at various dates. As part of the agreement, we hired a team of Terumo employees. Additionally, we entered into a distribution partnership with Terumo, in which Terumo will commercialize DuraHeart II in Japan and potentially other parts of Asia, if and when local regulatory approvals are obtained.
	The DuraHeart II acquisition was accounted for as a business combination by us. In connection with the acquisition, we recorded $2.0 million of acquisition-related costs, which were recognized in our consolidated statement of operations in fiscal 2013 within operating expenses. We also recorded $9.9 million of goodwill, equal to the amount by which the purchase consideration exceeded the fair value of the Purchased Assets. This goodwill was allocated to our sole operating segment and is deductible for U.S. income tax purposes. We will be obligated to pay potential post-closing cash milestone payments of $5.5 million and $10.5 million upon Conformité Européene (“CE”) Mark approval in Europe and U.S. Food and Drug Administration (“FDA”) approval, respectively, for the DuraHeart II device currently under development (collectively referred to as the “regulatory milestones”). Additional milestone payments totaling $27.5 million will become payable by us upon reaching various commercial sale milestones after the regulatory approvals are obtained (referred to as the “commercial sales milestones”). The fair value of the combined contingent consideration due upon achievement of the regulatory milestones and the commercial sales milestones was estimated to be $18.8 million at the acquisition date and has been recorded as a non-current liability, because such contingent consideration is expected to be settled no earlier than 2016.
	Total purchase price consideration was as follows (in thousands):
	Cash paid at the acquisition closing date (June 30, 2013)	$	13,000
	Estimated fair value of contingent consideration	18,800
	Total estimated purchase price	$	31,800
	We determined the initial fair value of the contingent consideration in connection with the regulatory and commercial sales milestones using various estimates, including probabilities of success, discount rates and the estimated amount of time until the conditions of the milestone payments are met. This fair value measurement was based on significant inputs not observable in the market, representing a Level 3 measurement within the fair value hierarchy (see Note 3 for more information about fair value measurements). The key assumptions used to determine the fair value of the contingent consideration at the acquisition date in connection with the regulatory milestones included a discount rate and probability-adjusted milestone payment date ranges. The key assumptions used to determine the fair value of contingent consideration at the acquisition date in connection with the commercial sales milestones included a discount rate and probability-weighted expected milestone payment date ranges based on the aggregate number of commercial units sold. In the three months ended March 29, 2014, the fair value of the contingent consideration decreased by $0.5 million as a result of changes in the probabilities of possible outcome, offset by accretion expense associated with the passage of time. The net change was reported as a decrease in research and development expense of $1.6 million, in part offset by an increase in selling, general and administrative expense of $1.1 million in the condensed consolidated statement of operations for the three months ended March 29, 2014.
	Purchase Price Allocation as of the acquisition date is summarized as follows (in thousands):
	Property, plant and equipment	$	8,900
	Identifiable intangible assets:
	Favorable lease contract	600
	IPR&D asset	12,400
	Goodwill	9,900
	Total estimated purchase price consideration	31,800
	Less: Contingent consideration	18,800
	Cash paid at the acquisition closing	$	13,000
	We recorded an IPR&D asset of $12.4 million, which represents an estimate of the fair value of the in-process technology related to the DuraHeart II device. The fair value of the IPR&D asset was determined using the multi-period excess earnings method which is equal to the present value of the incremental after-tax cash flows attributable to that intangible asset, discounted based on our best estimate of a market participant’s after-tax weighted average cost of capital.
	We recorded equipment totaling $8.9 million based on the fair value at the acquisition date. Of that amount, $8.1 million is related to certain equipment that is expected to be primarily used in the production of DuraHeart II units in anticipation of future clinical trials and throughout the commercialization of the product. Depreciation will commence upon production of the DuraHeart II units.
	The following pro forma information presents the combined results of operations for the three months ended March 30, 2013 as if we had completed the DuraHeart II acquisition at the beginning of 2012. The pro forma financial information is provided for comparative purposes only and is not necessarily indicative of what actual results would have been had the acquisition occurred on the date indicated, nor does it give effect to synergies, cost savings, fair market value adjustments, immaterial depreciation expense and other changes expected to result from the acquisition. Accordingly, the pro forma financial results do not purport to be indicative of condensed consolidated results of operations as of the date hereof, for any period ended on the date hereof, or for any other future date or period.
		Three months
		Ended
		March 30,
		2013
	Product sales	$	117,725
	Income before taxes	16,518
	Net income	12,247

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 29, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	Note 3. Fair Value Measurements
	Our financial assets and liabilities carried at fair value are primarily comprised of investments in money market funds, certificates of deposit, municipal and corporate bonds, commercial paper, variable demand notes, asset-backed securities, auction rate securities (ARS), forward contracts, certain investments held as assets under the deferred compensation plan, marketable equity securities and the contingent consideration in connection with acquisitions. The fair value accounting guidance requires that assets and liabilities be carried at fair value and classified in one of the following three categories:
	Level 1: Quoted prices in active markets for identical assets or liabilities that we have the ability to access
	Level 2: Observable market based inputs or unobservable inputs that are corroborated by market data such as quoted prices, interest rates and yield curves
	Level 3: Inputs that are unobservable data points that are not corroborated by market data
	We review the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. There were no transfers between Level 1, Level 2 and Level 3 during either of the three months ended March 29, 2014 or March 30, 2013.
	The following table represents the fair value hierarchy for our financial assets and financial liabilities measured at fair value on a recurring basis:
		Total Fair			Level 1			Level 2			Level 3
		Value
		(in thousands)
	As of March 29, 2014:
	Cash equivalents:
	Money market funds	$	58,561		$	58,561		$	—		$	—
	Commercial paper	32,347			—			32,347			—
	Municipal bonds	3,820			—			3,820			—
	Short-term investments:
	Municipal bonds	154,094			—			154,094			—
	Asset-backed securities	3,470			—			3,470			—
	Corporate bonds	16,227			—			16,227			—
	Commercial paper	10,744			—			10,744			—
	Certificate of deposit	2,000			—			2,000			—
	Prepaid expenses and other assets:
	Foreign exchange contracts	1,113			—			1,113			—
	Long-term investments:
	Auction rate securities	4,247			—			—			4,247
	Other long-term assets:
	Investments included in our deferred compensation plan	2,017			—			2,017			—
	Marketable equity securities	2,397			2,397			—			—
	Other accrued liabilities:
	Foreign exchange contracts	1,589			—			1,589			—
	Contingent consideration (current and non-current portions)	$	35,917		$	—		$	—		$	35,917
		Total Fair			Level 1			Level 2			Level 3
		Value
		(in thousands)
	As of December 28, 2013:
	Cash equivalents:
	Money market funds	$	97,200		$	97,200		$	—		$	—
	Commercial paper	13,899			—			13,899			—
	Short-term investments:
	Municipal bonds	142,486			—			142,486			—
	Variable demand notes	6,700			—			6,700			—
	Corporate bonds	5,507			—			5,507			—
	Commercial paper	9,998			—			9,998			—
	Certificate of deposit	2,000			—			2,000			—
	Prepaid expenses and other assets:
	Foreign exchange contracts	592			—			592			—
	Long-term investments:
	Auction rate securities	4,234			—			—			4,234
	Other long-term assets:
	Investments included in our deferred compensation plan	1,700			—			1,700			—
	Marketable equity securities	4,019			4,019			—			—
	Other accrued liabilities:
	Foreign exchange contracts	156			—			156			—
	Contingent consideration (current and non-current portions)	$	43,346		$	—		$	—		$	43,346
	Financial assets and liabilities are considered Level 2 when their fair values are determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data such as pricing for similar securities, recently executed transactions, cash flow models with yield curves and benchmark securities. Our Level 2 financial assets and liabilities include short-term investments, foreign exchange instruments and certain of our deferred compensation plan securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis.
	Financial assets and liabilities are considered Level 3 when their fair values are determined using pricing models, discounted cash flow methodologies or similar techniques, and at least one significant model assumption or input is unobservable. Level 3 financial assets and liabilities include the following:
	Auction rate securities—Due to limited market activity the determination of fair value requires significant judgment or estimation. These available-for-sale debt securities were valued using a discounted cash-flow model over a five-year period based on estimated interest rates, the present value of future principal payments, and interest payments discounted at rates considered to reflect the current market conditions and the credit quality of auction rate securities.
	Contingent consideration—The fair value of the contingent consideration related to the acquisition of the medical business of Levitronix LLC (Levitronix Medical) in August 2011 requires significant management judgment or estimation and is calculated using the income approach, using various revenue assumptions and applying a probability to each outcome. The fair value of the contingent consideration is remeasured at the end of each reporting period with the change in fair value recorded within operating expense in our condensed consolidated statements of operations. Actual amounts paid may differ from the obligations recorded. The accretion of interest expense was not significant for all periods presented. Refer to Note 2 for a discussion of the fair value of the contingent consideration associated with the DuraHeart II acquisition.
	Available-for-sale investments are carried at fair value and are included in the tables above under short- and long-term investments. The aggregate market value, cost basis and gross unrealized gains and losses of available-for-sale investments by major security type are as follows:
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
		(in thousands)
As of March 29, 2014:
Short-term investments:
Municipal bonds	$	153,938		$	167		$	(11	)	$	154,094
Corporate bonds	16,269			5			(47		)	16,227
Commercial paper	10,744			—			—			10,744
Asset-backed securities	3,472			—			(2		)	3,470
Certificate of deposit	2,000			—			—			2,000
Total short-term investments	$	186,423		$	172		$	(60	)	$	186,535
Long-term investments:
Auction rate securities	$	4,900		$	—		$	(653	)	$	4,247
Other long-term assets:
Marketable equity securities	2,996			—			(599		)	2,397
Total long-term	$	7,896		$	—		$	(1,252	)	$	6,644
As of December 28, 2013:
Short-term investments:
Municipal bonds	$	142,321		$	178		$	(13	)	$	142,486
Variable demand notes	6,700			—			—			6,700
Corporate bonds	5,500			7			—			5,507
Commercial paper	9,998			—			—			9,998
Certificate of deposit	2,000			—			—			2,000
Total short-term investments	$	166,519		$	185		$	(13	)	$	166,691
Long-term investments:
Auction rate securities	$	4,900		$	—		$	(666	)	$	4,234
Other long-term assets:
Marketable equity securities	2,996			1,023			—			4,019
Total long-term	$	7,896		$	1,023		$	(666	)	$	8,253
Our deferred compensation plan includes our corporate owned life insurance policies and mutual fund investments. The underlying mutual fund investments are deemed trading securities. The mutual fund investments’ fair value and the cash surrender value of our corporate-owned life insurance policies are classified in the condensed consolidated balance sheets in “Other long-term assets.” The aggregate value of our deferred compensation plan assets as of March 29, 2014 and December 28, 2013 was $5.6 million and $5.2 million, respectively. The unrealized gain before tax from the change in the value of the deferred compensation plan was not significant in the three months ended March 29, 2014 and March 30, 2013.
The amortized cost and fair value of available-for-sale debt investments, by contractual maturity, were as follows as of March 29, 2014:
	Amortized			Fair
	Cost			Value
	(in thousands)
Maturing within 1 year	$	147,924		$	148,008
Maturing after 1 year through 5 years	38,499			38,527
Short-term available-for-sale investments	186,423			186,535
Maturing after 5 years	4,900			4,247
	$	191,323		$	190,782
The following table provides a roll forward of the fair value, as determined by Level 3 inputs, of the ARS during the first quarter of 2014:
	Auction
	Rate
	Securities
	(in thousands)
Balance as of December 28, 2013	$	4,234
Unrealized holding gain on auction rate securities, included in other comprehensive income (loss)	13
Balance as of March 29, 2014	$	4,247
The following table provides a roll forward of the fair value, as determined by Level 3 inputs, of contingent consideration during the first quarter of 2014:
	Contingent
	Consideration
	(in thousands)
Balance as of December 28, 2013	$	43,346
Payments	(6,962		)
Change in fair value	(467		)
Balance as of March 29, 2014	$	35,917
The following table presents quantitative information about the inputs and valuation methodologies used for our fair value measurements classified in Level 3 of the fair value hierarchy as of March 29, 2014:
	Fair Value at			Valuation Methodology		Significant Unobservable Input		Weighted Average
	March 29, 2014							(range, if applicable)
	(in thousands)
Auction rate securities	$	4,247		Discounted cash flow		Discount rate		1.74%
						Market credit spread		2.81%
						Liquidity factor		0.00%
Levitronix Medical Contingent consideration	$	15,290		Multiple outcome discounted cash flow		Annual Revenue		$42.8 million ($31.5 million to $49.9 million)
						Discount rate		1.10% (0.8% to 1.51%)
						Probability of occurrence		20% (2.5% to 50%)
DuraHeart II Contingent consideration	$	20,627		Multiple outcome discounted cash flow		Milestone dates		2016 to 2029
						Discount rate		5.3% to 17.0%
						Probability of occurrence		5% to 80%
Auction Rate Securities
The significant unobservable inputs used in the fair value measurement of ARS are the weighted average discount rate, market credit spread and liquidity factor. A significant increase (decrease) in the discount rate in isolation could result in a significantly higher (lower) fair value measurement, whereas a significant increase (decrease) in the market credit spread and liquidity factor in isolation could result in a significantly lower (higher) fair value measurement. Although the discount rate as compared to the market credit spread and liquidity factors are not directly related, they will generally move in opposite directions.
The fair value of ARS is calculated on a quarterly basis by senior management based on a collaborative effort of the corporate treasury and accounting groups. To assess the reasonableness of the fair value measurement, management compares its fair value measurement to the values calculated by independent third parties.
Contingent Consideration
The estimated fair value of the liability for contingent consideration represents revenue and milestone targets related to our Levitronix Medical and DuraHeart II acquisitions, respectively. The fair value of the liability is determined using a discounted cash flow methodology with significant inputs that include projected revenue, discount rate and percentage probability of occurrence for the Levitronix Medical contingent consideration; and regulatory milestone targets, commercial milestones targets, discount rate and percent probability of occurrence of these milestones for the DuraHeart II contingent consideration. A significant increase (decrease) in the projected revenue in isolation could result in a significantly higher (lower) fair value measurement; a significant delay (acceleration) in the projected regulatory milestone achievement date in isolation could result in a significantly lower (higher) fair value measurement; a significant increase (decrease) in the discount rate in isolation could result in a significantly lower (higher) fair value measurement; and the changes in the probability of occurrence between the outcomes in isolation could result in a significant change in fair value measurement.
The fair value of the contingent consideration is calculated on a quarterly basis by management based on a collaborative effort of our regulatory, research and development, operations, finance and accounting groups. Potential valuation adjustments are made as additional information becomes available, including the progress toward achieving revenue and milestone targets as compared to initial projections, the impact of market competition and changes in actual and projected product mix and average selling price, with the impact of such adjustments being recorded in the condensed consolidated statement of operations. In the first quarter of 2014, we recorded a remeasurement adjustment to the DuraHeart II contingent consideration in the amount of $0.5 million. No adjustment was recorded to the Levitronix contingent consideration other than the payment made in the amount of $7.0 million in the first quarter of 2014.
Assets and Liabilities That Are Measured at Fair Value on a Nonrecurring Basis
Non-financial assets such as goodwill, intangible assets and property, plant, and equipment are evaluated for impairment and adjusted to fair value using Level 3 inputs, only when an impairment is recognized. Fair values are considered Level 3 when management makes significant assumptions in developing a discounted cash flow model based upon a number of considerations including projections of revenues, earnings and a discount rate. In addition, in evaluating the fair value of goodwill impairment, further corroboration is obtained using our market capitalization. No impairment was recorded in either the three months ended March 29, 2014 or March 30, 2013.

Foreign_Exchange_Instruments

Foreign Exchange Instruments	3 Months Ended
	Mar. 29, 2014
Foreign Exchange Instruments	'
Foreign Exchange Instruments	'
	Note 4. Foreign Exchange Instruments
	We utilize foreign currency forward exchange contracts and options with recognized financial institutions to manage our exposure to the impact of fluctuations in foreign currency exchange rates on certain intercompany balances and foreign currency denominated sales and purchase transactions. We do not use derivative financial instruments for speculative or trading purposes. These forward contracts are not designated as hedging instruments for accounting purposes. Principal hedged currencies include the Euro, British Pound Sterling and U.S. Dollar. The periods of these forward contracts range up to six months and the notional amounts are intended to be consistent with changes in the underlying exposures. We intend to exchange foreign currencies for U.S. Dollars at maturity.
	Total gross notional amounts for outstanding derivatives instruments were as follows:
		March 29, 2014			December 28, 2013
	Forward contracts:
	Euro (sell)	€	16.2 million		€	20.2 million
	British Pound Sterling (sell)	£	1.3 million		£	1.3 million
	U.S. Dollar (sell)	$	35.0 million		$	23.5 million
	U.S. Dollar (buy)	$	59.0 million		$	60.0 million
	The following table shows the derivative instruments measured at gross fair value reported on the condensed consolidated balance sheets:
		As of March 29, 2014						As of December 28, 2013
		Prepaid expenses			Other accrued			Prepaid expenses		Other accrued
		and other assets			liabilities			and other assets		liabilities
		(in thousands)
	Derivatives not designated as hedging instruments (forward contracts)	$	1,113		$	1,589		$	592	$	156
	The following table shows the effect of derivative instruments not designated as hedging instruments and foreign currency transactions gains and losses which were included in “Interest income and other” in the condensed consolidated statements of operations:
		Three Months Ended
		March 29, 2014			March 30, 2013
		(in thousands)
	Foreign currency exchange gain (loss) on foreign contracts	$	353		$	2,781
	Foreign currency transactions gain (loss)	(410		)	(2,445		)

Balance_Sheet_Information

Balance Sheet Information	3 Months Ended
	Mar. 29, 2014
Balance Sheet Information	'
Balance Sheet Information	'
	Note 5. Balance Sheet Information
	The following tables provide details of selected condensed consolidated balance sheets items as of the end of each period:
	Inventories consisted of the following:
		March 29,			December 28,
		2014			2013
		(in thousands)
	Finished goods	$	23,297		$	22,885
	Work in process	14,255			13,739
	Raw materials	21,793			23,669
	Total	$	59,345		$	60,293
	Property, plant and equipment, net consisted of the following:
		March 29,			December 28,
		2014			2013
		(in thousands)
	Land, building and improvements	$	20,594		$	20,594
	Equipment and capitalized software (A)	63,246			61,383
	Furniture and leasehold improvements	22,761			22,458
	Total	106,601			104,435
	Less accumulated depreciation	(51,517		)	(49,272		)
	Total	$	55,084		$	55,163
	(A)       Includes approximately $8.9 million of equipment from the DuraHeart II acquisition in 2013.
	Depreciation expense in the three months ended March 29, 2014 and March 30, 2013 was $2.1 million and $1.9 million, respectively.
	Warranty provision, included in “Other accrued liabilities” on the condensed consolidated balance sheets, and the changes in the balances for the three months ended March 29, 2014 and March 30, 2013 were as follows:
		March 29,			March 30,
		2014			2013
		(in thousands)
	Balance, beginning of the period	$	9,899		$	2,212
	Additions	909			113
	Settlements	(1,162		)	(459		)
	Balance, end of the period	$	9,646		$	1,866
	Changes in Accumulated Other Comprehensive Loss by component during the three months ended March 29, 2014:
		Foreign currency			Unrealized			Total
		items (A)			gain (loss) on
					available-for-sale
					securities (A)
		(in thousands)
	Balance as of December 28, 2013	$	(13,039	)	$	536		$	(12,503	)
	Other comprehensive loss before reclassification	1,459			(1,411		)	48
	Net current period other comprehensive loss	1,459			(1,411		)	48
	Balance as of March 29, 2014	$	(11,580	)	$	(875	)	$	(12,455	)
	(A)       All amounts are net of tax.

Goodwill_and_Purchased_Intangi

Goodwill and Purchased Intangible Assets, net	3 Months Ended
	Mar. 29, 2014
Goodwill and Purchased Intangible Assets, net	'
Goodwill and Purchased Intangible Assets, net	'
	Note 6. Goodwill and Purchased Intangible Assets, net
	The carrying amount of goodwill and the changes in the balances for the three months ended March 29, 2014 were as follows (in thousands):
	Balance as of December 28, 2013	$	205,764
	Foreign currency translation impact	1,262
	Balance as of March 29, 2014	$	207,026
	Intangible assets (net of accumulated amortization and impairment) were as follows:
		As of March 29, 2014
		Gross		Accumulated			Accumulated			Net
		Amount		Amortization			Impairment			Amount
		(in thousands)
	Intangible assets subject to amortization:
	Patents and trademarks	$	43,532	$	(35,047	)	$	—		$	8,485
	Core technology	37,180		(23,203		)	(12,642		)	1,335
	Developed technology	128,073		(82,356		)	(37,600		)	8,117
	Pre-existing license agreement	2,300		(876		)	—			1,424
	Customer based relationships and other	7,246		(4,508		)	—			2,738
	Foreign currency translation impact	94		—			—			94
		218,425		(145,990		)	(50,242		)	22,193
	Intangible assets not yet subject to amortization:
	IPR&D (see Note 2)	12,400		—			—			12,400
	Total purchased intangible assets	$	230,825	$	(145,990	)	$	(50,242	)	$	34,593
		As of December 28, 2013
		Gross		Accumulated			Accumulated			Net
		Amount		Amortization			Impairment			Amount
		(in thousands)
	Intangible assets subject to amortization:
	Patents and trademarks	$	43,532	$	(34,755	)	$	—		$	8,777
	Core technology	37,180		(22,986		)	(12,642		)	1,552
	Developed technology	128,073		(81,635		)	(37,600		)	8,838
	Pre-existing license agreement	2,300		(794		)	—			1,506
	Customer based relationships and other	7,246		(4,043		)	—			3,203
	Foreign currency translation impact	127		—			—			127
		218,458		(144,213		)	(50,242		)	24,003
	Intangible assets not yet subject to amortization:
	IPR&D (see Note 2)	12,400		—			—			12,400
	Total purchased intangible assets	$	230,858	$	(144,213	)	$	(50,242	)	$	36,403
	Amortization expense related to identifiable intangible assets in the three months ended March 29, 2014 and March 30, 2013 was $1.9 million and $2.5 million, respectively.
	Estimated amortization expenses for the next five fiscal years and all years thereafter, excluding intangible assets not yet subject to amortization are as follows:
		(in thousands)
	Fiscal year:
	Remainder of 2014	$	5,314
	2015	4,757
	2016	3,457
	2017	2,580
	2018	2,163
	Thereafter	3,922
	Total	$	22,193

Credit_Facility

Credit Facility	3 Months Ended
	Mar. 29, 2014
Credit Facility	'
Credit Facility	'
	Note 7. Credit Facility
	On December 19, 2011, we signed an unsecured revolving credit facility agreement that provides for up to $50.0 million revolving credit that will expire on December 19, 2016. The interest rate charged on the amounts borrowed is LIBOR plus a margin (ranging from 0.75% to 1.25%). The agreement contains financial covenants with which we were in compliance as of March 29, 2014. The credit agreement permits us to use the facility for working capital and general corporate purposes. We did not have any borrowings under this credit facility during the three months ended March 29, 2014 or March 30, 2013.

Legal_Proceeding

Legal Proceeding	3 Months Ended
	Mar. 29, 2014
Legal Proceeding	'
Legal Proceeding	'
	Note 8. Legal Proceeding
	From time to time we are involved in litigation arising out of claims in the normal course of business. Based on the information presently available, management believes that there are no claims or actions pending or threatened against us, the ultimate resolution of which will have a material effect on our financial position, liquidity or results of operations, although the results of litigation are inherently uncertain.
	On January 24, 2014, we and three of our present and former officers were named as defendants in a complaint filed in the United States District Court for the Northern District of California. The action, entitled Cooper v. Thoratec Corp., Case No. 4:14-cv-00360, is a putative class action brought on behalf of purchasers of our securities between April 29, 2010, and November 27, 2013, inclusive (the “Class Period”), and alleges violations of Section 10(b) of the Securities Exchange Act of 1934 (the “Exchange Act”), and Rule 10b-5 promulgated thereunder, as well as Section 20(a) of the Exchange Act. The complaint alleges that during the Class Period, the Company made false or misleading statements in our financial reports, SEC filings and press releases regarding our business and outlook, focusing primarily on the Company’s alleged failure to disclose that the HeartMate II Left Ventricular Assist Device had a purported significant risk of pump thrombosis. Plaintiffs seek unspecified damages, among other relief. On April 21, 2014, the Court appointed Bradley Cooper as Lead Plaintiff. Plaintiffs will have until June 20, 2014 to file a consolidated amended class action complaint. Although the results of litigation are inherently uncertain, based on the information currently available, we do not believe the ultimate resolution of this action will have a material effect on our financial position, liquidity or results of operations.

ShareBased_Compensation

Share-Based Compensation	3 Months Ended
	Mar. 29, 2014
Share-Based Compensation	'
Share-Based Compensation	'
	Note 9. Share-Based Compensation
	Our 2006 Incentive Stock Plan permits the issuance of stock options (“options”), restricted stock units (“RSUs”), performance share units (“PSUs”) and other types of awards to employees, directors, and consultants. As of March 29, 2014, approximately 1.7 million shares remained available for issuance under the 2006 Plan.
	Share-based compensation consisted of the following:
		Three Months Ended
		March 29, 2014			March 30, 2013
		(in thousands)
	Cost of goods sold	$	621		$	571
	Selling, general and administrative	4,025			3,683
	Research and development	2,136			1,913
	Total share-based compensation expense before taxes	6,782			6,167
	Tax benefit for share-based compensation expense	2,272			2,280
	Total share-based compensation (net of taxes)	$	4,510		$	3,887
	Share-based compensation costs of $0.6 million and $0.5 million were capitalized to inventory as of March 29, 2014 and December 28, 2013, respectively.
	Stock Options
	The fair value of each option is estimated at the date of grant using the Black-Scholes option-pricing model with the following assumptions:
		Three Months Ended
		March 29, 2014		March 30, 2013
	Risk-free interest rate (weighted average)	2.19	%	1.36	%
	Expected volatility	37	%	37	%
	Expected option life (years)	4.96 years		4.92 to 5.93 years
	Dividends	None		None
	Stock option activity is summarized as follows:
		Number of		Weighted			Weighted Average
		Options		Average Exercise			Remaining Contract
		(in thousands)		Price Per Share			Life (years)
	Outstanding options as of December 28, 2013	2,261		$	29.68		6.95
	Granted	536		35
	Exercised	(130	)	20.38
	Forfeited or expired	(14	)	36.04
	Outstanding options as of March 29, 2014	2,653		$	31.17		7.6
	Outstanding options exercisable as of March 29, 2014	1,250		$	27.72		6.08
	Outstanding options vested as of March 29, 2014 and expected to vest	2,546		$	31.03		7.53
	As of March 29, 2014, there was $11.4 million of unrecognized compensation expense, net of estimated forfeitures, related to options, which expense we expect to recognize over a weighted average period of 1.94 years. The weighted average grant-date fair value of options granted in the first quarter of 2014 was $12.39 per share.
	Restricted Stock Units
	Restricted stock unit activity is summarized as follows:
		Number of		Weighted Average			Weighted Average
		Units		Grant-Date Fair			Remaining Contract
		(in thousands)		Value			Life (in years)
	Outstanding units as of December 28, 2013	1,461		$	33.4		1.27
	Granted	498		35.04
	Released	(408	)	32.12
	Forfeited or expired	(27	)	34.74
	Outstanding units as of March 29, 2014	1,524		$	34.26		1.76
	As of March 29, 2014, there was $43.9 million of unrecognized compensation expense, net of estimated forfeitures, related to RSUs, which amount we expect to recognize over 2.7 years.
	Performance Share Units
	In the first quarter of 2014, we issued approximately 69,000 PSUs to certain employees with a weighted average grant-date fair value of $35.00 per PSU. The number of shares ultimately received will depend on a specified performance target over the performance period. Fifty percent of the shares awarded vest at the end of the performance period and remaining shares vest twenty-five percent on each of the following two anniversaries after the performance period assuming continued service by the employee. Delivery of the shares is conditioned upon achievement of the target and, if the target is achieved, occurs as of the applicable vesting date. We estimate the fair value of the PSUs based on the number of PSUs that are expected to be earned multiplied by the market price of our common stock on the date of grant. As the performance target is considered a performance condition, the expense for these awards, net of estimated forfeitures, is recorded over the four year vesting period based on a graded accelerated vesting method.
	As of March 29, 2014, there was $2.6 million of unrecognized compensation expense, net of estimated forfeitures, related to PSUs, which we expect to recognize over a weighted average period of 2.72 years.

Common_and_Preferred_Stock

Common and Preferred Stock	3 Months Ended
	Mar. 29, 2014
Common and Preferred Stock	'
Common and Preferred Stock	'
	Note 10. Common and Preferred Stock
	On December 5, 2013, the Board of Directors authorized a new program to repurchase up to $200.0 million of our shares of common stock (“December 2013 program”), which will expire on December 31, 2015. In the three months ended March 29, 2014, we repurchased $12.3 million worth of shares of our common stock under the December 2013 program, of which $0.6 million was accrued on the condensed consolidated balance sheet as of March 29, 2014. In addition, we repurchased $1.2 million worth of shares of our common stock in the first quarter of 2014 under our previous November 2012 program which expired on December 31, 2013.
	As of March 29, 2014, $187.7 million was available for repurchases of shares of our common stock under the December 2013 program.
	We are incorporated in California, and as California law does not recognize treasury stock, the shares repurchased decreased the common shares outstanding. We recorded the $13.5 million of shares repurchased in the three months ended March 29, 2014 by reducing the additional paid-in-capital (“APIC”) balance by the average value per share reflected in the account prior to the repurchase and allocating the excess as a reduction of retained earnings. Based on this allocation, APIC decreased by $4.7 million and retained earnings decreased by $8.8 million in the consolidated statement of shareholders’ equity.
	We also purchased shares of our common stock that were not part of our publicly announced repurchase program, which represent the surrender value of shares of restricted stock units withheld in order to satisfy tax withholding obligations upon vesting. The shares purchased do not reduce the dollar value that may yet be purchased under our publicly announced repurchase programs. The aggregate value of shares purchased in three months ended March 29, 2014 was $6.7 million, which decreased APIC and retained earnings by $2.3 million and $4.4 million, respectively, based on the same allocation methodology discussed above. The aggregate value of shares purchased in three months ended March 28, 2013 was $5.8 million, which decreased APIC and retained earnings by $1.9 million and $3.9 million, respectively.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 29, 2014
Income Taxes	'
Income Taxes	'
	Note 11. Income Taxes
	Our effective income tax rates in the first quarter of 2014 and 2013 were 32.6% and 25.9%, respectively. The increase is primarily due to the lack of federal R&D credits in the absence of enacted legislation in 2014. In the first quarter of 2013, we recognized a benefit of approximately $1.6 million for qualifying amounts, of which $1.3 million relates to the 2012 credits recognized as a result of the timing of legislation.
	During the next 12 months, it is reasonably possible that audit resolutions and the expiration of statutes of limitations could potentially reduce our unrecognized tax benefits by up to $1.5 million. However, this amount may change because we continue to have ongoing negotiations with various taxing authorities throughout the year.

Segment_and_Geographic_Informa

Segment and Geographic Information	3 Months Ended
	Mar. 29, 2014
Segment and Geographic Information	'
Segment and Geographic Information	'
	Note 12. Segment and Geographic Information
	We have one operating segment and, and therefore, one reportable segment which develops, manufactures and markets proprietary medical devices used for mechanical circulatory support for the treatment of heart failure patients. Our chief operating decision-maker reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance, accompanied by disaggregated revenue information by product line. We do not assess the performance of our individual product lines on measures of profit or loss, or asset-based metrics. Therefore, the information below is presented only for revenues by product line, geography, and certain revenue category.
	Product sales attributed to a country or region include product sales to hospitals, physicians and distributors and are based on final destinations where the products are sold. No individual customer or individual country outside of the U.S. accounted for more than 10% of product sales in either the first quarter of 2014 or 2013.
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by geographic location:
	Domestic	$	95,605	$	92,269
	International	30,092		25,456
	Total	$	125,697	$	117,725
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by product line:
	HeartMate	$	110,011	$	102,921
	CentriMag	12,994		10,364
	PVAD and IVAD	2,252		3,832
	Other	440		608
	Total	$	125,697	$	117,725
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by category:
	Pump	$	89,300	$	84,331
	Non-Pump	35,957		32,786
	Other	440		608
	Total	$	125,697	$	117,725

Net_Income_Per_Share

Net Income Per Share	3 Months Ended
	Mar. 29, 2014
Net Income Per Share	'
Net Income Per Share	'
	13. Net Income Per Share
	We calculate basic earnings per share (“EPS”) using net earnings and the weighted-average number of shares outstanding during the reporting period. Diluted EPS includes any dilutive effect of outstanding options and RSUs. PSUs are excluded from the shares used to compute diluted EPS until performance condition is met.
	The reconciliations of the numerators and denominators of each of the basic and diluted EPS calculations were as follows:
		Three Months Ended
		March 29, 2014		March 30, 2013
		(stated in thousands, except per share amounts)
	Numerator:
	Net income	$	18,239	$	18,170
	Denominator:
	Weighted average shares used to compute basis EPS	56,840		57,486
	Dilutive effect of share—based compensation plans	826		1,021
	Weighted average shares used to compute diluted EPS	57,666		58,507
	Net income per share:
	Basic	$	0.32	$	0.32
	Diluted	$	0.32	$	0.31
	Options to purchase 686,000 and 775,000 shares of common stock were not included in the computation of diluted earnings per share for the three months ended March 29, 2014 and March 30, 2013, respectively, because their effect would have been antidilutive.

Operations_and_Significant_Acc1

Operations and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 29, 2014
Operations and Significant Accounting Policies	'
Basis of Presentation	'
	Basis of Presentation
	The interim unaudited condensed consolidated financial statements of Thoratec Corporation (“we,” “our,” “us,” or the “Company”) have been prepared and presented in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”), without audit, and reflect all adjustments necessary (consisting only of normal recurring adjustments) to present fairly our financial position, results of operations and cash flows as of and for the periods presented. Certain information and footnote disclosures normally included in our annual financial statements, prepared in accordance with GAAP, have been condensed or omitted. The accompanying financial statements should be read in conjunction with our fiscal 2013 consolidated financial statements, and the accompanying notes thereto, filed with the SEC in our 2013 Annual Report on Form 10-K for the fiscal year ended December 28, 2013 (the “2013 Annual Report”). The operating results for any interim period are not necessarily indicative of the results that may be expected for any future period.
	The preparation of our unaudited condensed consolidated financial statements necessarily requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities on the unaudited condensed consolidated balance sheet dates and the reported amounts of revenues and expenses for the periods presented. The actual amounts could differ from those estimated amounts.

Acquisition_of_DuraHeart_II_Ta

Acquisition of DuraHeart II (Tables)	3 Months Ended
	Mar. 29, 2014
Acquisition of DuraHeart II	'
Schedule of purchase price consideration	'
	Total purchase price consideration was as follows (in thousands):
	Cash paid at the acquisition closing date (June 30, 2013)	$	13,000
	Estimated fair value of contingent consideration	18,800
	Total estimated purchase price	$	31,800
Summary of purchase price allocation as of the acquisition date	'
	Purchase Price Allocation as of the acquisition date is summarized as follows (in thousands):
	Property, plant and equipment	$	8,900
	Identifiable intangible assets:
	Favorable lease contract	600
	IPR&D asset	12,400
	Goodwill	9,900
	Total estimated purchase price consideration	31,800
	Less: Contingent consideration	18,800
	Cash paid at the acquisition closing	$	13,000
Schedule of pro forma financial information	'
		Three months
		Ended
		March 30,
		2013
	Product sales	$	117,725
	Income before taxes	16,518
	Net income	12,247

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 29, 2014
Fair Value Measurements	'
Financial assets and financial liabilities measured at fair value on a recurring basis	'
		Total Fair			Level 1			Level 2			Level 3
		Value
		(in thousands)
	As of March 29, 2014:
	Cash equivalents:
	Money market funds	$	58,561		$	58,561		$	—		$	—
	Commercial paper	32,347			—			32,347			—
	Municipal bonds	3,820			—			3,820			—
	Short-term investments:
	Municipal bonds	154,094			—			154,094			—
	Asset-backed securities	3,470			—			3,470			—
	Corporate bonds	16,227			—			16,227			—
	Commercial paper	10,744			—			10,744			—
	Certificate of deposit	2,000			—			2,000			—
	Prepaid expenses and other assets:
	Foreign exchange contracts	1,113			—			1,113			—
	Long-term investments:
	Auction rate securities	4,247			—			—			4,247
	Other long-term assets:
	Investments included in our deferred compensation plan	2,017			—			2,017			—
	Marketable equity securities	2,397			2,397			—			—
	Other accrued liabilities:
	Foreign exchange contracts	1,589			—			1,589			—
	Contingent consideration (current and non-current portions)	$	35,917		$	—		$	—		$	35,917
		Total Fair			Level 1			Level 2			Level 3
		Value
		(in thousands)
	As of December 28, 2013:
	Cash equivalents:
	Money market funds	$	97,200		$	97,200		$	—		$	—
	Commercial paper	13,899			—			13,899			—
	Short-term investments:
	Municipal bonds	142,486			—			142,486			—
	Variable demand notes	6,700			—			6,700			—
	Corporate bonds	5,507			—			5,507			—
	Commercial paper	9,998			—			9,998			—
	Certificate of deposit	2,000			—			2,000			—
	Prepaid expenses and other assets:
	Foreign exchange contracts	592			—			592			—
	Long-term investments:
	Auction rate securities	4,234			—			—			4,234
	Other long-term assets:
	Investments included in our deferred compensation plan	1,700			—			1,700			—
	Marketable equity securities	4,019			4,019			—			—
	Other accrued liabilities:
	Foreign exchange contracts	156			—			156			—
	Contingent consideration (current and non-current portions)	$	43,346		$	—		$	—		$	43,346
Summary of aggregate market value, cost basis and gross unrealized gains and losses for available-for-sale investments	'
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
		(in thousands)
	As of March 29, 2014:
	Short-term investments:
	Municipal bonds	$	153,938		$	167		$	(11	)	$	154,094
	Corporate bonds	16,269			5			(47		)	16,227
	Commercial paper	10,744			—			—			10,744
	Asset-backed securities	3,472			—			(2		)	3,470
	Certificate of deposit	2,000			—			—			2,000
	Total short-term investments	$	186,423		$	172		$	(60	)	$	186,535
	Long-term investments:
	Auction rate securities	$	4,900		$	—		$	(653	)	$	4,247
	Other long-term assets:
	Marketable equity securities	2,996			—			(599		)	2,397
	Total long-term	$	7,896		$	—		$	(1,252	)	$	6,644
	As of December 28, 2013:
	Short-term investments:
	Municipal bonds	$	142,321		$	178		$	(13	)	$	142,486
	Variable demand notes	6,700			—			—			6,700
	Corporate bonds	5,500			7			—			5,507
	Commercial paper	9,998			—			—			9,998
	Certificate of deposit	2,000			—			—			2,000
	Total short-term investments	$	166,519		$	185		$	(13	)	$	166,691
	Long-term investments:
	Auction rate securities	$	4,900		$	—		$	(666	)	$	4,234
	Other long-term assets:
	Marketable equity securities	2,996			1,023			—			4,019
	Total long-term	$	7,896		$	1,023		$	(666	)	$	8,253
Schedule of amortized cost and fair value of available-for-sale debt investments, by contractual maturity	'
	The amortized cost and fair value of available-for-sale debt investments, by contractual maturity, were as follows as of March 29, 2014:
		Amortized			Fair
		Cost			Value
		(in thousands)
	Maturing within 1 year	$	147,924		$	148,008
	Maturing after 1 year through 5 years	38,499			38,527
	Short-term available-for-sale investments	186,423			186,535
	Maturing after 5 years	4,900			4,247
		$	191,323		$	190,782
Schedule of roll forward of fair value, as determined by Level 3 inputs, of auction rate securities and contingent consideration (current and long-term portions)	'
		Auction
		Rate
		Securities
		(in thousands)
	Balance as of December 28, 2013	$	4,234
	Unrealized holding gain on auction rate securities, included in other comprehensive income (loss)	13
	Balance as of March 29, 2014	$	4,247
		Contingent
		Consideration
		(in thousands)
	Balance as of December 28, 2013	$	43,346
	Payments	(6,962		)
	Change in fair value	(467		)
	Balance as of March 29, 2014	$	35,917
Schedule of quantitative information for Level 3 Fair Value Measurements	'
		Fair Value at			Valuation Methodology		Significant Unobservable Input		Weighted Average
		March 29, 2014							(range, if applicable)
		(in thousands)
	Auction rate securities	$	4,247		Discounted cash flow		Discount rate		1.74%
							Market credit spread		2.81%
							Liquidity factor		0.00%
	Levitronix Medical Contingent consideration	$	15,290		Multiple outcome discounted cash flow		Annual Revenue		$42.8 million ($31.5 million to $49.9 million)
							Discount rate		1.10% (0.8% to 1.51%)
							Probability of occurrence		20% (2.5% to 50%)
	DuraHeart II Contingent consideration	$	20,627		Multiple outcome discounted cash flow		Milestone dates		2016 to 2029
							Discount rate		5.3% to 17.0%
							Probability of occurrence		5% to 80%

Foreign_Exchange_Instruments_T

Foreign Exchange Instruments (Tables)	3 Months Ended
	Mar. 29, 2014
Foreign Exchange Instruments	'
Schedule of notional amount of foreign currency contracts, which do not qualify for hedge accounting	'
		March 29, 2014			December 28, 2013
	Forward contracts:
	Euro (sell)	€	16.2 million		€	20.2 million
	British Pound Sterling (sell)	£	1.3 million		£	1.3 million
	U.S. Dollar (sell)	$	35.0 million		$	23.5 million
	U.S. Dollar (buy)	$	59.0 million		$	60.0 million
Schedule of derivative instruments measured at gross fair value reported on the condensed consolidated balance sheets	'
		As of March 29, 2014						As of December 28, 2013
		Prepaid expenses			Other accrued			Prepaid expenses		Other accrued
		and other assets			liabilities			and other assets		liabilities
		(in thousands)
	Derivatives not designated as hedging instruments (forward contracts)	$	1,113		$	1,589		$	592	$	156
Schedule of effect of derivative instruments not designated as hedging instruments and foreign currency transactions gains and losses	'
		Three Months Ended
		March 29, 2014			March 30, 2013
		(in thousands)
	Foreign currency exchange gain (loss) on foreign contracts	$	353		$	2,781
	Foreign currency transactions gain (loss)	(410		)	(2,445		)

Balance_Sheet_Information_Tabl

Balance Sheet Information (Tables)	3 Months Ended
	Mar. 29, 2014
Balance Sheet Information	'
Schedule of Inventories	'
		March 29,			December 28,
		2014			2013
		(in thousands)
	Finished goods	$	23,297		$	22,885
	Work in process	14,255			13,739
	Raw materials	21,793			23,669
	Total	$	59,345		$	60,293
Schedule of Property, Plant and Equipment, net	'
		March 29,			December 28,
		2014			2013
		(in thousands)
	Land, building and improvements	$	20,594		$	20,594
	Equipment and capitalized software (A)	63,246			61,383
	Furniture and leasehold improvements	22,761			22,458
	Total	106,601			104,435
	Less accumulated depreciation	(51,517		)	(49,272		)
	Total	$	55,084		$	55,163
	(A)       Includes approximately $8.9 million of equipment from the DuraHeart II acquisition in 2013.
Changes in the warranty provision	'
		March 29,			March 30,
		2014			2013
		(in thousands)
	Balance, beginning of the period	$	9,899		$	2,212
	Additions	909			113
	Settlements	(1,162		)	(459		)
	Balance, end of the period	$	9,646		$	1,866
Schedule of changes in accumulated other comprehensive loss by component	'
		Foreign currency			Unrealized			Total
		items (A)			gain (loss) on
					available-for-sale
					securities (A)
		(in thousands)
	Balance as of December 28, 2013	$	(13,039	)	$	536		$	(12,503	)
	Other comprehensive loss before reclassification	1,459			(1,411		)	48
	Net current period other comprehensive loss	1,459			(1,411		)	48
	Balance as of March 29, 2014	$	(11,580	)	$	(875	)	$	(12,455	)
	(A)       All amounts are net of tax.

Goodwill_and_Purchased_Intangi1

Goodwill and Purchased Intangible Assets, net (Tables)	3 Months Ended
	Mar. 29, 2014
Goodwill and Purchased Intangible Assets, net	'
Schedule of changes in carrying amount of goodwill	'
	The carrying amount of goodwill and the changes in the balances for the three months ended March 29, 2014 were as follows (in thousands):
	Balance as of December 28, 2013	$	205,764
	Foreign currency translation impact	1,262
	Balance as of March 29, 2014	$	207,026
Schedule of intangible assets on the condensed consolidated balance sheets	'
		As of March 29, 2014
		Gross		Accumulated			Accumulated			Net
		Amount		Amortization			Impairment			Amount
		(in thousands)
	Intangible assets subject to amortization:
	Patents and trademarks	$	43,532	$	(35,047	)	$	—		$	8,485
	Core technology	37,180		(23,203		)	(12,642		)	1,335
	Developed technology	128,073		(82,356		)	(37,600		)	8,117
	Pre-existing license agreement	2,300		(876		)	—			1,424
	Customer based relationships and other	7,246		(4,508		)	—			2,738
	Foreign currency translation impact	94		—			—			94
		218,425		(145,990		)	(50,242		)	22,193
	Intangible assets not yet subject to amortization:
	IPR&D (see Note 2)	12,400		—			—			12,400
	Total purchased intangible assets	$	230,825	$	(145,990	)	$	(50,242	)	$	34,593
		As of December 28, 2013
		Gross		Accumulated			Accumulated			Net
		Amount		Amortization			Impairment			Amount
		(in thousands)
	Intangible assets subject to amortization:
	Patents and trademarks	$	43,532	$	(34,755	)	$	—		$	8,777
	Core technology	37,180		(22,986		)	(12,642		)	1,552
	Developed technology	128,073		(81,635		)	(37,600		)	8,838
	Pre-existing license agreement	2,300		(794		)	—			1,506
	Customer based relationships and other	7,246		(4,043		)	—			3,203
	Foreign currency translation impact	127		—			—			127
		218,458		(144,213		)	(50,242		)	24,003
	Intangible assets not yet subject to amortization:
	IPR&D (see Note 2)	12,400		—			—			12,400
	Total purchased intangible assets	$	230,858	$	(144,213	)	$	(50,242	)	$	36,403
Schedule of estimated amortization expense for the next five fiscal years and all years thereafter	'
		(in thousands)
	Fiscal year:
	Remainder of 2014	$	5,314
	2015	4,757
	2016	3,457
	2017	2,580
	2018	2,163
	Thereafter	3,922
	Total	$	22,193

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 29, 2014
Share-Based Compensation	'
Schedule of share-based compensation	'
		Three Months Ended
		March 29, 2014			March 30, 2013
		(in thousands)
	Cost of goods sold	$	621		$	571
	Selling, general and administrative	4,025			3,683
	Research and development	2,136			1,913
	Total share-based compensation expense before taxes	6,782			6,167
	Tax benefit for share-based compensation expense	2,272			2,280
	Total share-based compensation (net of taxes)	$	4,510		$	3,887
Schedule of assumptions used to estimate the grant date fair value of options	'
		Three Months Ended
		March 29, 2014		March 30, 2013
	Risk-free interest rate (weighted average)	2.19	%	1.36	%
	Expected volatility	37	%	37	%
	Expected option life (years)	4.96 years		4.92 to 5.93 years
	Dividends	None		None
Summary of stock option activity	'
		Number of		Weighted			Weighted Average
		Options		Average Exercise			Remaining Contract
		(in thousands)		Price Per Share			Life (years)
	Outstanding options as of December 28, 2013	2,261		$	29.68		6.95
	Granted	536		35
	Exercised	(130	)	20.38
	Forfeited or expired	(14	)	36.04
	Outstanding options as of March 29, 2014	2,653		$	31.17		7.6
	Outstanding options exercisable as of March 29, 2014	1,250		$	27.72		6.08
	Outstanding options vested as of March 29, 2014 and expected to vest	2,546		$	31.03		7.53
Summary of restricted stock unit activity	'
		Number of		Weighted Average			Weighted Average
		Units		Grant-Date Fair			Remaining Contract
		(in thousands)		Value			Life (in years)
	Outstanding units as of December 28, 2013	1,461		$	33.4		1.27
	Granted	498		35.04
	Released	(408	)	32.12
	Forfeited or expired	(27	)	34.74
	Outstanding units as of March 29, 2014	1,524		$	34.26		1.76

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	3 Months Ended
	Mar. 29, 2014
Segment and Geographic Information	'
Schedule of product sales by geographic location	'
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by geographic location:
	Domestic	$	95,605	$	92,269
	International	30,092		25,456
	Total	$	125,697	$	117,725
Schedule of product sales by product line	'
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by product line:
	HeartMate	$	110,011	$	102,921
	CentriMag	12,994		10,364
	PVAD and IVAD	2,252		3,832
	Other	440		608
	Total	$	125,697	$	117,725
Schedule of product sales by category	'
		Three Months Ended
		March 29,		March 30,
		2014		2013
		(in thousands)
	Product sales by category:
	Pump	$	89,300	$	84,331
	Non-Pump	35,957		32,786
	Other	440		608
	Total	$	125,697	$	117,725

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	3 Months Ended
	Mar. 29, 2014
Net Income Per Share	'
Schedule of reconciliations of the numerators and denominators of each of the basic and diluted EPS calculations	'
		Three Months Ended
		March 29, 2014		March 30, 2013
		(stated in thousands, except per share amounts)
	Numerator:
	Net income	$	18,239	$	18,170
	Denominator:
	Weighted average shares used to compute basis EPS	56,840		57,486
	Dilutive effect of share—based compensation plans	826		1,021
	Weighted average shares used to compute diluted EPS	57,666		58,507
	Net income per share:
	Basic	$	0.32	$	0.32
	Diluted	$	0.32	$	0.31

Acquisition_of_DuraHeart_II_De

Acquisition of DuraHeart II (Details) (USD $)

3 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

Mar. 29, 2014

Dec. 28, 2013

Jun. 30, 2013

Dec. 28, 2013

Jun. 30, 2013

Jun. 30, 2013

Mar. 29, 2014

Mar. 29, 2014

Mar. 29, 2014

Jun. 30, 2013

Jun. 30, 2013

Jun. 30, 2013

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

DuraHeart II Acquisition

IPR&D asset

Favorable lease contract

Contingent consideration payable upon reaching regulatory milestone

Contingent consideration payable upon reaching regulatory milestone

Contingent consideration payable upon reaching regulatory milestone

Contingent consideration payable upon CE Mark approval

Contingent consideration payable upon FDA approval

Contingent consideration payable upon reaching commercial sales milestone

Selling, general and administrative expense

Research and development

Acquisition of DuraHeart II

'

'

'

'

'

'

'

'

'

'

'

'

Cash paid

'

'

$13,000,000

'

'

'

'

'

'

'

'

'

Potential future milestone payments

'

'

43,500,000

'

'

'

'

'

'

5,500,000

10,500,000

27,500,000

Acquisition-related costs

'

'

'

2,000,000

'

'

'

'

'

'

'

'

Goodwill recorded as a result of business acquisition that is deductible for income tax purposes

'

'

9,900,000

'

'

'

'

'

'

'

'

'

Fair value of non-current contingent consideration liability

26,728,000

36,384,000

18,800,000

'

'

'

'

'

'

'

'

'

Total preliminary purchase price consideration

'

'

'

'

'

'

'

'

'

'

'

'

Cash paid

'

'

13,000,000

'

'

'

'

'

'

'

'

'

Estimated fair value of contingent consideration

'

'

18,800,000

'

'

'

'

'

'

'

'

'

Total estimated purchase price

'

'

31,800,000

'

'

'

'

'

'

'

'

'

Increase (decrease) in fair value of contingent consideration

'

'

'

'

'

'

-500,000

1,100,000

-1,600,000

'

'

'

Summary of purchase price allocation

'

'

'

'

'

'

'

'

'

'

'

'

Property, plant and equipment

'

'

8,900,000

'

'

'

'

'

'

'

'

'

Finite-lived identifiable intangible assets

'

'

'

'

'

600,000

'

'

'

'

'

'

Indefinite-lived identifiable intangible assets

'

'

'

'

12,400,000

'

'

'

'

'

'

'

Goodwill

207,026,000

205,764,000

9,900,000

'

'

'

'

'

'

'

'

'

Total estimated purchase price consideration

'

'

31,800,000

'

'

'

'

'

'

'

'

'

Less: Contingent consideration

'

'

18,800,000

'

'

'

'

'

'

'

'

'

Cash paid at the acquisition closing

'

'

13,000,000

'

'

'

'

'

'

'

'

'

Equipment expected to be primarily used in the production of units in anticipation of future clinical trials

'

'

8,100,000

'

'

'

'

'

'

'

'

'

Pro forma financial information

'

'

'

'

'

'

'

'

'

'

'

'

Product sales

117,725,000

'

'

'

'

'

'

'

'

'

'

'

Income before taxes

16,518,000

'

'

'

'

'

'

'

'

'

'

'

Net income

$12,247,000

'

'

'

'

'

'

'

'

'

'

'

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)

3 Months Ended

In Thousands, unless otherwise specified

Mar. 29, 2014

Mar. 30, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Commercial Paper

Commercial Paper

Municipal bonds

Municipal bonds

Asset-backed securities

Variable demand notes

Corporate bonds

Corporate bonds

Long-term investments - auction rate securities

Long-term investments - auction rate securities

Certificate of deposit

Certificate of deposit

Marketable equity securities

Marketable equity securities

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Recurring basis

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Total fair value

Quoted prices in active markets for identical assets (Level 1)

Quoted prices in active markets for identical assets (Level 1)

Quoted prices in active markets for identical assets (Level 1)

Quoted prices in active markets for identical assets (Level 1)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant unobservable inputs (Level 3)

Significant unobservable inputs (Level 3)

Significant unobservable inputs (Level 3)

Significant unobservable inputs (Level 3)

Money market funds

Money market funds

Commercial Paper

Commercial Paper

Municipal bonds

Municipal bonds

Asset-backed securities

Variable demand notes

Corporate bonds

Corporate bonds

Long-term investments - auction rate securities

Long-term investments - auction rate securities

Certificate of deposit

Certificate of deposit

Marketable equity securities

Marketable equity securities

Money market funds

Money market funds

Marketable equity securities

Marketable equity securities

Commercial Paper

Commercial Paper

Municipal bonds

Municipal bonds

Asset-backed securities

Variable demand notes

Corporate bonds

Corporate bonds

Certificate of deposit

Certificate of deposit

Long-term investments - auction rate securities

Long-term investments - auction rate securities

Financial assets and liabilities measured at fair value on a recurring basis

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Transfers between the levels within the fair value hierarchy

$0

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash equivalents

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

58,561

97,200

32,347

13,899

3,820

'

'

'

'

'

'

'

'

'

'

'

58,561

97,200

'

'

'

'

32,347

13,899

3,820

'

'

'

'

'

'

'

'

'

'

'

Investments

'

'

10,744

9,998

154,094

142,486

3,470

6,700

16,227

5,507

4,247

4,234

2,000

2,000

2,397

4,019

'

'

'

'

10,744

9,998

154,094

142,486

3,470

6,700

16,227

5,507

4,247

4,234

2,000

2,000

2,397

4,019

'

'

2,397

4,019

'

'

10,744

9,998

154,094

142,486

3,470

6,700

16,227

5,507

2,000

2,000

'

'

4,247

4,234

Prepaid expenses and other assets - Foreign exchange contracts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,113

592

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,113

592

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other long term assets: Carrying value of investments included in our deferred compensation plan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,017

1,700

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,017

1,700

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other accrued liabilities - Foreign exchange contracts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,589

156

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,589

156

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contingent consideration (current and non-current portions)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$35,917

$43,346

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$35,917

$43,346

'

'

Cash flow model discount period

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (USD $)	3 Months Ended	12 Months Ended
	Mar. 29, 2014	Dec. 28, 2013
Other long-term assets - investments - deferred compensation plan	'	'
Deferred compensation plan assets	$5,600,000	$5,200,000
Contractual maturities of available-for-sale investments, Amortized Cost	'	'
Total Amortized Cost	191,323,000	'
Contractual maturities of available-for-sale investments, Fair Value	'	'
Total Fair Value	190,782,000	'
Short-term investments	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	186,423,000	166,519,000
Gross Unrealized Gains	172,000	185,000
Gross Unrealized Losses	-60,000	-13,000
Fair Value	186,535,000	166,691,000
Contractual maturities of available-for-sale investments, Amortized Cost	'	'
Maturing within 1 year	147,924,000	'
Maturing after 1 year through 5 years	38,499,000	'
Total Amortized Cost	186,423,000	'
Maturing after 5 years	4,900,000	'
Contractual maturities of available-for-sale investments, Fair Value	'	'
Maturing within 1 year	148,008,000	'
Maturing after 1 year through 5 years	38,527,000	'
Total Fair Value	186,535,000	'
Maturing after 5 years	4,247,000	'
Municipal bonds	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	153,938,000	142,321,000
Gross Unrealized Gains	167,000	178,000
Gross Unrealized Losses	-11,000	-13,000
Fair Value	154,094,000	142,486,000
Variable demand notes	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	'	6,700,000
Fair Value	'	6,700,000
Corporate bonds	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	16,269,000	5,500,000
Gross Unrealized Gains	5,000	7,000
Gross Unrealized Losses	-47,000	'
Fair Value	16,227,000	5,507,000
Commercial Paper	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	10,744,000	9,998,000
Fair Value	10,744,000	9,998,000
Asset-backed securities	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	3,472,000	'
Gross Unrealized Losses	-2,000	'
Fair Value	3,470,000	'
Certificate of deposit	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	2,000,000	2,000,000
Fair Value	2,000,000	2,000,000
Long-term investments	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	7,896,000	7,896,000
Gross Unrealized Gains	'	1,023,000
Gross Unrealized Losses	-1,252,000	-666,000
Fair Value	6,644,000	8,253,000
Long-term investments - auction rate securities	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	4,900,000	4,900,000
Gross Unrealized Losses	-653,000	-666,000
Fair Value	4,247,000	4,234,000
Marketable equity securities	'	'
Available-for-sale investments by major security type:	'	'
Amortized Cost	2,996,000	2,996,000
Gross Unrealized Gains	'	1,023,000
Gross Unrealized Losses	-599,000	'
Fair Value	$2,397,000	$4,019,000

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 3) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014
Auction rate securities	'
Reconciliation of the beginning and ending balances for the assets measured as fair value using significant unobservable inputs (Level 3):	'
Balance, beginning of the fiscal year	$4,234
Unrealized holding gain on auction rate securities, included in other comprehensive income (loss)	13
Balance, end of the fiscal year	4,247
Contingent consideration	'
Changes in liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3)	'
Balance, beginning of the fiscal year	43,346
Payments	-6,962
Change in fair value	-467
Balance, end of the fiscal year	$35,917

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details 4) (Auction rate securities, Discounted cash flow, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014
Quantitative information for Level 3 Fair Value Measurements Assets	'
Fair value Assets	4,247
Weighted Average	'
Quantitative information for Level 3 Fair Value Measurements Assets	'
Discount rate (as a percent)	1.74%
Market credit spread (as a percent)	2.81%
Liquidity factor (as a percent)	0.00%

Fair_Value_Measurements_Detail4

Fair Value Measurements (Details 5) (USD $)	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Payment of contingent consideration	($6,107,000)	($4,220,000)
Impairment charges	0	0
Levitronix Medical	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Adjustments to contingent consideration	0	'
Payment of contingent consideration	7,000,000	'
DuraHeart II Acquisition	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Adjustments to contingent consideration	500,000	'
Multiple outcome discounted cash flow | Levitronix Medical	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Fair value Liabilities	15,290,000	'
Multiple outcome discounted cash flow | DuraHeart II Acquisition	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Fair value Liabilities	20,627,000	'
Multiple outcome discounted cash flow | Minimum | Levitronix Medical	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Annual Revenue	31,500,000	'
Discount rate (as a percent)	0.80%	'
Probability of occurrence (as a percent)	2.50%	'
Multiple outcome discounted cash flow | Minimum | DuraHeart II Acquisition	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Discount rate (as a percent)	5.30%	'
Probability of occurrence (as a percent)	5.00%	'
Multiple outcome discounted cash flow | Maximum | Levitronix Medical	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Annual Revenue	49,900,000	'
Discount rate (as a percent)	1.51%	'
Probability of occurrence (as a percent)	50.00%	'
Multiple outcome discounted cash flow | Maximum | DuraHeart II Acquisition	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Discount rate (as a percent)	17.00%	'
Probability of occurrence (as a percent)	80.00%	'
Multiple outcome discounted cash flow | Weighted Average | Levitronix Medical	'	'
Quantitative information for Level 3 Fair Value Measurements Liabilities	'	'
Annual Revenue	$42,800,000	'
Discount rate (as a percent)	1.10%	'
Probability of occurrence (as a percent)	20.00%	'

Foreign_Exchange_Instruments_D

Foreign Exchange Instruments (Details)

3 Months Ended

3 Months Ended

Mar. 29, 2014

Mar. 30, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

Mar. 29, 2014

Dec. 28, 2013

USD ($)

USD ($)

Prepaid expenses and other assets

Prepaid expenses and other assets

Other accrued liabilities

Other accrued liabilities

Not Designated

Not Designated

Not Designated

Not Designated

Not Designated

Not Designated

Not Designated

Not Designated

Not Designated

USD ($)

USD ($)

USD ($)

USD ($)

Maximum

Euro (sell)

Euro (sell)

British Pound Sterling (sell)

British Pound Sterling (sell)

U.S. Dollar (sell)

U.S. Dollar (sell)

U.S. Dollar (buy) 1

U.S. Dollar (buy) 1

EUR (€)

EUR (€)

GBP (£)

GBP (£)

USD ($)

USD ($)

USD ($)

USD ($)

Foreign currency forward exchange details

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Approximate period forward contracts

'

'

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

Gross notional amounts for outstanding derivatives

'

'

'

'

'

'

'

€ 16,200,000

€ 20,200,000

£ 1,300,000

£ 1,300,000

$35,000,000

$23,500,000

$59,000,000

$60,000,000

Gross fair value of Derivatives not designated as hedging instruments (forward contracts)

'

'

1,113,000

592,000

1,589,000

156,000

'

'

'

'

'

'

'

'

'

Foreign currency exchange gain (loss) on foreign contracts

353,000

2,781,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign currency transactions gain (loss)

($410,000)

($2,445,000)

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance_Sheet_Information_Deta

Balance Sheet Information (Details) (USD $)	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013	Dec. 28, 2013
Inventories	'	'	'
Finished goods	$23,297,000	'	$22,885,000
Work-in-process	14,255,000	'	13,739,000
Raw materials	21,793,000	'	23,669,000
Total inventories	59,345,000	'	60,293,000
Property, plant and equipment, net	'	'	'
Property, plant and equipment, gross	106,601,000	'	104,435,000
Less accumulated depreciation	-51,517,000	'	-49,272,000
Total property, plant and equipment, net	55,084,000	'	55,163,000
Depreciation expense	2,100,000	1,900,000	'
Changes in the warranty provision	'	'	'
Balance, beginning of the fiscal year	9,899,000	2,212,000	'
Additions	909,000	113,000	'
Settlements	-1,162,000	-459,000	'
Balance, end of the fiscal year	9,646,000	1,866,000	'
Land, building and improvements	'	'	'
Property, plant and equipment, net	'	'	'
Property, plant and equipment, gross	20,594,000	'	20,594,000
Equipment and capitalized software	'	'	'
Property, plant and equipment, net	'	'	'
Property, plant and equipment, gross	63,246,000	'	61,383,000
Equipment and capitalized software | DuraHeart II Acquisition	'	'	'
Property, plant and equipment, net	'	'	'
Property, plant and equipment, gross	8,900,000	'	8,900,000
Furniture and leasehold improvements	'	'	'
Property, plant and equipment, net	'	'	'
Property, plant and equipment, gross	$22,761,000	'	$22,458,000

Balance_Sheet_Information_Deta1

Balance Sheet Information (Details 2) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
Changes in accumulated other comprehensive loss	'	'
Balance at the beginning of the period	($12,503)	'
Other comprehensive loss before reclassification	48	'
Total other comprehensive income (loss)	48	-2,070
Balance at the end of the period	-12,455	'
Foreign currency items	'	'
Changes in accumulated other comprehensive loss	'	'
Balance at the beginning of the period	-13,039	'
Other comprehensive loss before reclassification	1,459	'
Total other comprehensive income (loss)	1,459	'
Balance at the end of the period	-11,580	'
Unrealized gain (loss) on available-for-sale securities	'	'
Changes in accumulated other comprehensive loss	'	'
Balance at the beginning of the period	536	'
Other comprehensive loss before reclassification	-1,411	'
Total other comprehensive income (loss)	-1,411	'
Balance at the end of the period	($875)	'

Goodwill_and_Purchased_Intangi2

Goodwill and Purchased Intangible Assets, net (Details) (USD $)	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013	Dec. 28, 2013
Changes in carrying amount of goodwill	'	'	'
Balance, beginning of the period	$205,764,000	'	'
Foreign currency translation impact	1,262,000	'	'
Balance, end of period	207,026,000	'	'
Intangible assets subject to amortization:	'	'	'
Accumulated impairment before adjustments	-50,242,000	'	-50,242,000
Foreign currency translation adjustments, gross	94,000	'	127,000
Foreign currency translation adjustments, net	94,000	'	127,000
Gross Carrying Amount	218,425,000	'	218,458,000
Accumulated Amortization	-145,990,000	'	-144,213,000
Total	22,193,000	'	24,003,000
Intangible assets not yet subject to amortization:	'	'	'
Total purchased intangible assets, gross	230,825,000	'	230,858,000
Total purchased intangible assets, net	34,593,000	'	36,403,000
Amortization expense related to identifiable intangible assets (subject to amortization)	1,900,000	2,500,000	'
Estimated amortization expense for the next five fiscal years and all years thereafter	'	'	'
Remainder of 2014	5,314,000	'	'
2015	4,757,000	'	'
2016	3,457,000	'	'
2017	2,580,000	'	'
2018	2,163,000	'	'
Thereafter	3,922,000	'	'
Total	22,193,000	'	24,003,000
IPR&D	'	'	'
Intangible assets not yet subject to amortization:	'	'	'
Total intangible assets not yet subject to amortization	12,400,000	'	12,400,000
Patents and trademarks	'	'	'
Intangible assets subject to amortization:	'	'	'
Gross carrying amount before adjustments	43,532,000	'	43,532,000
Accumulated amortization before adjustments	-35,047,000	'	-34,755,000
Net carrying amount before adjustments	8,485,000	'	8,777,000
Core technology	'	'	'
Intangible assets subject to amortization:	'	'	'
Gross carrying amount before adjustments	37,180,000	'	37,180,000
Accumulated amortization before adjustments	-23,203,000	'	-22,986,000
Accumulated impairment before adjustments	-12,642,000	'	-12,642,000
Net carrying amount before adjustments	1,335,000	'	1,552,000
Developed technology	'	'	'
Intangible assets subject to amortization:	'	'	'
Gross carrying amount before adjustments	128,073,000	'	128,073,000
Accumulated amortization before adjustments	-82,356,000	'	-81,635,000
Accumulated impairment before adjustments	-37,600,000	'	-37,600,000
Net carrying amount before adjustments	8,117,000	'	8,838,000
Pre-existing license agreements	'	'	'
Intangible assets subject to amortization:	'	'	'
Gross carrying amount before adjustments	2,300,000	'	2,300,000
Accumulated amortization before adjustments	-876,000	'	-794,000
Net carrying amount before adjustments	1,424,000	'	1,506,000
Customer based relationships and other	'	'	'
Intangible assets subject to amortization:	'	'	'
Gross carrying amount before adjustments	7,246,000	'	7,246,000
Accumulated amortization before adjustments	-4,508,000	'	-4,043,000
Net carrying amount before adjustments	$2,738,000	'	$3,203,000

Credit_Facility_Details

Credit Facility (Details) (Credit Facility, USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 29, 2014	Dec. 19, 2011
Credit facility	'	'
Maximum borrowing capacity	'	$50
Reference rate for variable rate (as a percent)	'LIBOR plus	'
Minimum	'	'
Credit facility	'	'
Margin rate (as a percent)	0.75%	'
Maximum	'	'
Credit facility	'	'
Margin rate (as a percent)	1.25%	'

Legal_Proceeding_Details

Legal Proceeding (Details)	3 Months Ended
	Mar. 29, 2014
	item
Acquisition	'
Number of present and former officers named as defendants in a complaint filed in the United States District Court	3

ShareBased_Compensation_Detail

Share-Based Compensation (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 29, 2014	Mar. 30, 2013	Dec. 28, 2013
Share-based compensation	'	'	'
Share-based compensation cost	$6,782,000	$6,167,000	'
Tax benefit for share-based compensation expense	2,272,000	2,280,000	'
Total share-based compensation (net of taxes)	4,510,000	3,887,000	'
Share-based compensation costs capitalized to inventory	600,000	'	500,000
Options	'	'	'
Share-based compensation	'	'	'
Remaining shares available for issuance	1,700,000	'	'
Method and assumptions on valuation of stock options	'	'	'
Risk-free interest rate (weighted average) (as a percent)	2.19%	1.36%	'
Expected volatility (as a percent)	37.00%	37.00%	'
Expected option life	'4 years 11 months 16 days	'	'
Dividends (as a percent)	0.00%	0.00%	'
Number of options	'	'	'
Outstanding options at the beginning of the period (in shares)	2,261,000	'	'
Granted (in shares)	536,000	'	'
Exercised (in shares)	-130,000	'	'
Forfeited or expired (in shares)	-14,000	'	'
Outstanding options at the end of the period (in shares)	2,653,000	'	2,261,000
Outstanding options exercisable at the end of the period (in shares)	1,250,000	'	'
Outstanding options vested at the end of the period and expected to vest (in shares)	2,546,000	'	'
Stock options, Weighted-Average Exercise Price Per Share	'	'	'
Outstanding options at the beginning of the period (in dollars per share)	$29.68	'	'
Granted (in dollars per share)	$35	'	'
Exercised (in dollars per share)	$20.38	'	'
Forfeited or expired (in dollars per share)	$36.04	'	'
Outstanding options at the end of the period (in dollars per share)	$31.17	'	$29.68
Outstanding options exercisable at the end of the period (in dollars per share)	$27.72	'	'
Outstanding options vested at the end of the period and expected to vest (in dollars per share)	$31.03	'	'
Weighted Average Remaining Contract Life (years)	'	'	'
Outstanding options at the beginning of the period	'7 years 7 months 6 days	'	'6 years 11 months 12 days
Outstanding options at the end of the period	'7 years 7 months 6 days	'	'6 years 11 months 12 days
Outstanding options exercisable at the end of the period	'6 years 29 days	'	'
Outstanding options vested at the end of the period and expected to vest	'7 years 6 months 11 days	'	'
Unrecognized compensation expenses, net of estimated forfeitures	11,400,000	'	'
Weighted average period for unrecognized compensation cost expected to be recognized	'1 year 11 months 8 days	'	'
Weighted average grant-date fair value (in dollars per share)	$12.39	'	'
Options | Minimum	'	'	'
Method and assumptions on valuation of stock options	'	'	'
Expected option life	'	'4 years 11 months 1 day	'
Options | Maximum	'	'	'
Method and assumptions on valuation of stock options	'	'	'
Expected option life	'	'5 years 11 months 5 days	'
Cost of goods sold	'	'	'
Share-based compensation	'	'	'
Share-based compensation cost	621,000	571,000	'
Selling, general and administrative	'	'	'
Share-based compensation	'	'	'
Share-based compensation cost	4,025,000	3,683,000	'
Research and development	'	'	'
Share-based compensation	'	'	'
Share-based compensation cost	$2,136,000	$1,913,000	'

ShareBased_Compensation_Detail1

Share-Based Compensation (Details 2) (Restricted stock units, USD $)	3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 29, 2014	Dec. 28, 2013
Restricted stock units	'	'
Number of shares and units	'	'
Outstanding units at the beginning of the period (in shares)	1,461,000	'
Granted (in shares)	498,000	'
Released (in shares)	-408,000	'
Forfeited or expired (in shares)	-27,000	'
Outstanding units at the end of the period (in shares)	1,524,000	1,461,000
Weighted average grant-date fair value	'	'
Outstanding units at the beginning of the year (in dollars per share)	$33.40	'
Granted (in dollars per share)	$35.40	'
Released (in dollars per share)	$32.12	'
Forfeited or expired (in dollars per share)	$34.74	'
Outstanding units at the end of the year (in dollars per share)	$34.26	$33.40
Weighted Average Remaining Contract Life (in years)	'	'
Weighted Average Remaining Contract Life	'1 year 9 months 4 days	'1 year 3 months 7 days
Weighted Average Remaining Contract Life	'1 year 9 months 4 days	'1 year 3 months 7 days
Unrecognized compensation expenses, net of estimated forfeitures	$43.90	'
Weighted average period for unrecognized compensation cost expected to be recognized	'2 years 8 months 12 days	'

ShareBased_Compensation_Detail2

Share-Based Compensation (Details 3) (Performance Share Units, USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 29, 2014
	item
Performance Share Units	'
Share-Based Compensation	'
Awards issued (in shares)	69,000
Weighted average grant-date fair value of awards issued (in dollars per share)	$35
Vesting rights percentage at the end of performance period	50.00%
Vesting rights percentage at each anniversary	25.00%
Number of remaining vesting anniversary after performance period	2
Vesting period	'4 years
Unrecognized compensation expenses, net of estimated forfeitures	$2.60
Weighted average period for unrecognized compensation cost expected to be recognized	'2 years 8 months 19 days

Common_and_Preferred_Stock_Det

Common and Preferred Stock (Details) (USD $)	0 Months Ended	3 Months Ended
In Millions, unless otherwise specified	Dec. 05, 2013	Mar. 29, 2014	Mar. 30, 2013
Common and Preferred Stock	'	'	'
Repurchases of shares of our common stock under stock repurchase programs	'	$187.70	'
Decrease in additional-paid-in-capital	'	2.3	1.9
Decrease in retained earnings	'	4.4	3.9
December 2013 program	'	'	'
Common and Preferred Stock	'	'	'
Maximum amount for repurchase of common stock	200	13.5	'
Repurchases of shares of our common stock under stock repurchase programs	'	12.3	'
Repurchased shares of common stock accrued on the condensed consolidated balance sheet	'	0.6	'
Decrease in additional-paid-in-capital	'	4.7	'
Decrease in retained earnings	'	8.8	'
Aggregate amount of common stock agreed to be repurchased	'	6.7	5.8
November 2012 program	'	'	'
Common and Preferred Stock	'	'	'
Maximum amount for repurchase of common stock	'	$1.20	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013	Dec. 28, 2013
Income Taxes	'	'	'
Effective income tax rates (as a percent)	32.60%	25.90%	'
Tax benefits recognized for qualifying amounts	'	$1.60	'
Tax benefits recognized due to enactment of law	'	1.3	'
Tax benefits expected to be recognized due to enactment of law	'	'	1.6
Reasonably possible potential reduction in unrecognized tax benefits over the next 12 months	$1.50	'	'

Segment_and_Geographic_Informa2

Segment and Geographic Information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
	segment
Segment and Geographic Information	'	'
Number of operating and reporting segment	1	'
Segment information	'	'
Product sales	$125,697	$117,725
HeartMate	'	'
Segment information	'	'
Product sales	110,011	102,921
CentriMag	'	'
Segment information	'	'
Product sales	12,994	10,364
PVAD and IVAD	'	'
Segment information	'	'
Product sales	2,252	3,832
Pump	'	'
Segment information	'	'
Product sales	89,300	84,331
Non-Pump	'	'
Segment information	'	'
Product sales	35,957	32,786
Other	'	'
Segment information	'	'
Product sales	440	608
Domestic	'	'
Segment information	'	'
Product sales	95,605	92,269
International	'	'
Segment information	'	'
Product sales	$30,092	$25,456

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 29, 2014	Mar. 30, 2013
Numerator:	'	'
Net income	$18,239	$18,170
Denominator:	'	'
Weighted average shares used to compute basis EPS	56,840,000	57,486,000
Dilutive effect of share-based compensation plans	826,000	1,021,000
Weighted average shares used to compute diluted EPS	57,666,000	58,507,000
Net income per share:	'	'
Basic (in dollars per share)	$0.32	$0.32
Diluted (in dollars per share)	$0.32	$0.31
Options	'	'
Potential common share equivalents excluded	'	'
Options to purchase shares not included in the computation of diluted income per share because their inclusion would be anti-dilutive	686,000	775,000