Wright Medical 10-K 27 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 30, 2018	Feb. 22, 2019	Jul. 01, 2018
Document Information [Line Items]
Entity Registrant Name	WRIGHT MEDICAL GROUP N.V.
Entity Central Index Key	1,492,658
Current Fiscal Year End Date	--12-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		125,857,608
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2,738,123,472

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 191,351	$ 167,740
Restricted Cash and Cash Equivalents, Current			150,000
Accounts receivable, net		141,019	130,610
Inventories		180,690	168,144
Prepaid expenses		11,823	13,555
Other current assets	[1]	78,349	86,845
Total current assets		603,232	566,894
Property, plant and equipment, net		224,929	212,379
Goodwill		1,268,954	933,662
Intangible assets, net		282,332	231,001
Deferred income taxes		942	937
Other assets	[1]	314,012	183,851
Total assets		2,694,401	2,128,724
Current liabilities:
Accounts payable		48,359	41,831
Accrued expenses and other current liabilities	[1]	217,081	314,558
Current portion of long-term obligations	[1],[2]	201,686	58,906
Total current liabilities		467,126	415,295
Long-term debt and capital lease obligations	[1]	913,441	836,208
Deferred income taxes		13,146	15,780
Other liabilities	[1]	368,229	272,745
Total liabilities		1,761,942	1,540,028
Commitments and contingencies
Stockholders' equity:
Ordinary shares, €0.03 par value, authorized: 320,000,000 shares; issued and outstanding: 125,555,751 shares at December 30, 2018 and 105,807,424 shares at December 31, 2017		4,589	3,896
Additional paid-in capital		2,514,295	1,971,347
Accumulated Other Comprehensive Income (Loss), Net of Tax		(8,083)	22,290
Retained earnings		(1,578,342)	(1,408,837)
Total stockholders' equity		932,459	588,696
Total liabilities and stockholders' equity		$ 2,694,401	$ 2,128,724
[1]	1 The holders of the 2020 Notes will have the ability to begin converting their 2020 Notes beginning August 15, 2019 through their maturity. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes and the fair value of the 2020 Notes Conversion Derivative were classified as current liabilities, and the fair value of the 2020 Notes Hedges was classified as current assets as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017. See Note 6 and Note 9.
[2]	1 The holders of the 2020 Notes may convert their notes at any time prior to August 15, 2019 solely into cash upon satisfaction of certain circumstances as described below. On or after August 15, 2019, holders may convert their 2020 Notes solely into cash, regardless of the foregoing circumstances. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes were classified as current liabilities as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017.

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical)	Dec. 30, 2018$ / sharesshares	Dec. 30, 2018€ / sharesshares	Dec. 31, 2017$ / sharesshares
Common Stock, Par or Stated Value Per Share | (per share)	$ 0.03	€ 0.03	$ 0.03
Common stock, shares authorized (in shares)	320,000,000	320,000,000	320,000,000
Common Stock, Shares, Issued	125,555,751	125,555,751	105,807,424

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017
Income Statement [Abstract]
Net sales	$ 217,602	$ 170,503	$ 179,693	$ 177,191
Cost of sales	47,278	38,421	38,122	37,126
Gross profit	170,324	132,082	141,571	140,065
Operating expenses:
Selling, general and administrative	133,149	131,421	130,818	129,834
Research and development	13,144	11,992	12,547	12,432
Amortization of intangible assets	6,822	7,178	6,999	7,397
Total operating expenses	153,115	150,591	150,364	149,663
Operating income	17,209	(18,509)	(8,793)	(9,598)
Income (Loss) from Continuing Operations Attributable to Parent	26,852	(34,122)	(20,960)	(36,707)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2,281	(97,748)	(20,202)	(21,992)
Net (loss) income	$ 29,133	$ (131,870)	$ (41,162)	$ (58,699)
Weighted Average Number of Shares Outstanding, Basic and Diluted	105,195	104,836	104,377	103,663
Net income (loss) per share (Note 15):
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.26	$ (0.33)	$ (0.20)	$ (0.35)
Income (Loss) from Continuing Operations, Per Diluted Share	0.25	(0.33)	(0.20)	(0.35)
Basic (in dollars per share)	0.28	(1.26)	(0.39)	(0.57)
Diluted (in dollars per share)	$ 0.27	$ (1.26)	$ (0.39)	$ (0.57)
Weighted-average number of shares outstanding, diluted (in shares)	106,578	104,836	104,377	103,663

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
InventoryStepUpAmortizationExpenseContinuingOperations			$ 37,700
Stock-based compensation expense	$ 26,100	$ 19,400	14,400
Cost of Sales [Member]
Stock-based compensation expense	585	565	414
Selling, general and administrative [Member]
Stock-based compensation expense	23,608	17,705	13,216
Research and Development [Member]
Stock-based compensation expense	$ 1,927	$ 1,123	$ 786

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Net (loss) income	$ (169,505)	$ (202,598)	$ (432,373)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Changes in foreign currency translation	(30,373)	41,751	(8,977)
Other Comprehensive Income (Loss)	(30,373)	41,751	(8,977)
Comprehensive Income (Loss)	(199,878)	(160,847)	(441,350)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Changes in foreign currency translation	$ (30,373)	$ 41,751	$ (8,977)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 30, 2018USD ($)		Dec. 31, 2017USD ($)		Dec. 25, 2016USD ($)
Statement of Cash Flows [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 191,351		$ 167,740		$ 262,300
Operating activities:
Net (loss) income	(169,505)		(202,598)		(432,373)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	59,500		56,800		55,800
Consolidated Depreciation			56,832		56,782
Stock-based compensation expense	26,120		19,393		14,416
Consolidated Intangible Amortization	26,730		28,396		29,180
Amortization of Financing Costs and Discounts	54,630		50,379		40,487
Deferred income taxes	(4,543)		(13,791)		(20,583)
Inventory Write-down	20,913		19,171		22,046
Write off of Deferred Debt Issuance Cost	39,935		0		12,343
InventoryStepUpAmortizationExpense	352		0		41,503
Non Cash Adjustment Derivative Fair Value	35,934		(4,797)		(28,273)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	0		0		21,342
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	140		5,320		8,688
Loss Contingency, Receivable, Period Increase (Decrease)	(42,044)		0		0
Other	(1,617)		1,385		4,425
Changes in assets and liabilities (net of acquisitions):
Accounts receivable	(8,223)		2,483		(1,118)
Inventories	(35,887)		(29,526)		(187)
Prepaid expenses and other current assets	45,712		(22,744)		22,441
Accounts payable	6,022		6,260		1,495
Accrued expenses and other liabilities	(14,839)		(21,834)		(11,251)
Increase (Decrease) in Metal on Metal Product Liability Accrual	(103,056)		(79,139)		256,461
Net cash provided by operating activities	(63,729)		(184,810)		37,824
Investing activities:
Capital expenditures	(71,467)		(63,474)		(50,099)
Acquisition of business	(434,289)		(44,128)		0
Purchase of intangible assets	(2,483)		(2,099)		(4,845)
Proceeds from Divestiture of Businesses	0		280		20,703
Payments to Acquire Investments	(2,000)
Net cash used in investing activities	(510,239)		(109,421)		(34,241)
Financing activities:
Issuance of common stock	21,618		27,551		8,460
Proceeds from Issuance or Sale of Equity	448,924
Payments of Stock Issuance Costs	(25,896)
Proceeds from Issuance of Warrants	102,137		0		54,629
Payments of long term borrowings	(141,278)		0		(99,816)
Payments for Repurchase of Warrants	(23,972)		0		(3,319)
Settlement of 2017 Notes Conversion Derivative	(55,643)		0		(1,619)
Proceeds from Hedge, Financing Activities	34,553		0		3,892
Redemption of convertible senior notes	(400,911)		0		(102,974)
Repayments of Assumed Debt	675,000		0		0
Proceeds From Cash Settled Convertible Debt	25,243		34,901		425,821
Repayments of Long-term Debt	(38,637)		(11,517)		0
Payment of Financing and Stock Issuance Costs	(14,701)		0		(10,110)
2023NotesEquityIssuanceCosts	(1,870)				(998)
Payment of contingent consideration - initial valuation	(919)		(1,429)		(1,035)
Repayments of Long-term Capital Lease Obligations	(5,508)		(2,690)		(2,514)
Net cash provided by (used in) financing activities	598,140		46,816		270,417
Effect of exchange rates on cash and cash equivalents	(561)		2,890		(1,539)
Net increase in cash and cash equivalents	23,611		(244,525)		272,461
Consolidated cash and cash equivalents, beginning of year	167,740	[1]	412,265	[1]	139,804	[1]
Consolidated Cash and Equivalents, end of year	$ 191,351	[1]	$ 167,740	[1]	412,265	[1]
Restricted Cash					$ 150,000
[1]	1 As of December 30, 2018, December 31, 2017, and December 25, 2016, we had cash and cash equivalents of $191.4 million, $167.7 million, and $262.3 million, respectively. As of December 25, 2016, we had $150.0 million in restricted cash to secure our obligations under a Master Settlement Agreement (MSA) that WMT entered into in connection with the metal-on-metal hip litigation as described in Note 16.

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands		Total		Common Stock [Member]		Additional Paid-in Capital [Member]		Retained Earnings [Member]		Accumulated Other Comprehensive Income [Member]	IMASCAP SAS [Member]	IMASCAP SAS [Member]Common Stock [Member]	IMASCAP SAS [Member]Additional Paid-in Capital [Member]	Accumulated Translation Adjustment [Member]Accumulated Other Comprehensive Income [Member]
Balance (in shares) at Dec. 27, 2015	[1]			102,672,678
Balance at Dec. 27, 2015		$ 1,055,026	[1]	$ 3,790	[1]	$ 1,835,586	[1]	$ (773,866)	[1]					$ (10,484)
Net (loss) income		(432,373)						(432,373)
Changes in foreign currency translation		(8,977)												(8,977)
Issuances of common stock (in shares)				440,355
Issuances of common stock		8,470		$ 15		8,455
Vesting of stock-settled phantom stock units and non-vested shares of common stock (in shares)				287,962
Vesting of stock-settled phantom stock units and non-vested shares of common stock				$ 10		(10)
Stock-based compensation		14,406				14,406
Balance (in shares) at Dec. 25, 2016				103,400,995
Balance at Dec. 25, 2016		686,864		$ 3,815		1,908,749		(1,206,239)		$ (19,461)
Adjustments to Additional Paid in Capital, Warrant Issued		50,312				50,312
Net (loss) income		(202,598)						(202,598)
Changes in foreign currency translation		41,751												41,751
Issuances of common stock (in shares)				1,352,549								661,753
Issuances of common stock		27,551		$ 45		27,506					$ 15,643	$ 23	$ 15,620
Vesting of stock-settled phantom stock units and non-vested shares of common stock (in shares)				392,127
Vesting of stock-settled phantom stock units and non-vested shares of common stock				$ 13		(13)
Stock-based compensation		19,485				19,485
Balance (in shares) at Dec. 31, 2017				105,807,424
Balance at Dec. 31, 2017		588,696		$ 3,896		1,971,347		(1,408,837)		22,290
Net (loss) income		(169,505)						(169,505)
Changes in foreign currency translation		(30,373)												$ (30,373)
Issuances of common stock (in shares)				1,043,685
Issuances of common stock		21,618		$ 36		21,582
Stock Issued During Period, Shares, Other				18,248,932
Stock Issued During Period, Value, Other		423,028		$ 641		422,387
Vesting of stock-settled phantom stock units and non-vested shares of common stock (in shares)				455,710
Vesting of stock-settled phantom stock units and non-vested shares of common stock				$ 16		(16)
Stock-based compensation		26,039				26,039
Balance (in shares) at Dec. 30, 2018				125,555,751
Balance at Dec. 30, 2018		932,459		$ 4,589		2,514,295		$ (1,578,342)		$ (8,083)
Adjustments to Additional Paid in Capital, Warrant Issued		$ 72,956				$ 72,956
[1]	During 2015, the 2014 balances of ordinary shares and additional paid in capital were restated to meet post-merger conversion values.

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 30, 2018
Organization and Description of Business [Abstract]
Organization and Description of Business	Organization and Description of Business Wright Medical Group N.V. is a global medical device company focused on extremities and biologics products. We are committed to delivering innovative, value-added solutions improving quality of life for patients worldwide and are a recognized leader of surgical solutions for the upper extremities (shoulder, elbow, wrist and hand), lower extremities (foot and ankle) and biologics markets, three of the fastest growing segments in orthopaedics. We market our products in approximately 50 countries worldwide. Our global corporate headquarters are located in Amsterdam, the Netherlands. We also have significant operations located in Memphis, Tennessee (U.S. headquarters, research and development, sales and marketing administration, and administrative activities); Bloomington, Minnesota (upper extremities sales and marketing and warehousing operations); Arlington, Tennessee (manufacturing and warehousing operations); Franklin, Tennessee (manufacturing and warehousing operations); Columbia City, Indiana (research and development); Alpharetta, Georgia (manufacturing and warehousing operations); Montbonnot, France (manufacturing and warehousing operations); Plouzané, France (research and development); and Macroom, Ireland (manufacturing). In addition, we have local sales and distribution offices in Canada, Australia, Asia, Latin America, and throughout Europe. For purposes of this report, references to “international” or “foreign” relate to non-U.S. matters while references to “domestic” relate to U.S. matters. Our common stock is traded on the Nasdaq Global Select Market under the symbol “WMGI.” Our fiscal year-end is generally determined on a 52-week basis and runs from the Monday nearest to the 31st of December of a year, and ends on the Sunday nearest to the 31st of December of the following year. Every few years, it is necessary to add an extra week to the year making it a 53-week period. The fiscal years ended December 30, 2018 and December 25, 2016 were 52-week periods. The fiscal year ended December 31, 2017 was a 53-week period. References in this report to a particular year generally refer to the applicable fiscal year. Accordingly, references to “ 2018 ” or “the year ended December 30, 2018 ” mean the fiscal year ended December 30, 2018 . The consolidated financial statements and accompanying notes present our consolidated results for each of the fiscal years in the three-year period ended December 30, 2018 , December 31, 2017 , and December 25, 2016 . All amounts are presented in U.S. dollars ($), except where expressly stated as being in other currencies, e.g., Euros (€). References in these notes to consolidated financial statements to “we,” “our” and “us” refer to Wright Medical Group N.V. and its subsidiaries after the Wright/Tornier merger and Wright Medical Group, Inc. and its subsidiaries before the Wright/Tornier merger.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of consolidation. The accompanying consolidated financial statements include our accounts and those of our controlled subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. Use of estimates. The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. The most significant areas requiring the use of management estimates relate to revenue recognition, the determination of allowances for doubtful accounts and excess and obsolete inventories, accounting for business combinations and the evaluation of goodwill and long-lived assets, valuation of in-process research and development, product liability claims, product liability insurance recoveries and other litigation, income taxes, and share-based compensation. Discontinued operations. On October 21, 2016, pursuant to a binding offer letter dated as of July 8, 2016, Tornier France SAS and certain other entities related to us and Corin entered into a business sale agreement and simultaneously completed and closed the sale of our Large Joints business. Pursuant to the terms of the agreement, we sold substantially all of our assets related to our Large Joints business to Corin for approximately €29.7 million in cash, less approximately €11.1 million for net working capital adjustments. Upon closing, the parties also executed a transitional services agreement and supply agreement, among other ancillary agreements required to implement the transaction. These agreements were on arm’s length terms and were not material to our financial statements. On January 9, 2014, pursuant to an Asset Purchase Agreement, dated as of June 18, 2013 (the MicroPort Agreement), by and among us and MicroPort, we completed the divesture and sale of our business operations operating under our prior OrthoRecon operating segment (the OrthoRecon Business) to MicroPort. Pursuant to the terms of the MicroPort Agreement, the purchase price (as defined in the agreement) for the OrthoRecon Business was approximately $283 million (including a working capital adjustment), which MicroPort paid in cash. All historical operating results for the Large Joints and OrthoRecon businesses, including costs associated with corporate employees and infrastructure transferred as a part of the sales, are reflected within discontinued operations in the consolidated statements of operations. See Note 4 for further discussion of discontinued operations. Other than Note 4 , unless otherwise stated, all discussion of assets and liabilities in these Notes to the Consolidated Financial Statements reflect the assets and liabilities held and used in our continuing operations, and all discussion of revenues and expenses reflect those associated with our continuing operations. Cash and cash equivalents. Cash and cash equivalents include all cash balances and short-term investments with original maturities of three months or less. Any such investments are readily convertible into known amounts of cash, and are so near their maturity that they present insignificant risk of changes in value because of interest rate variation. Inventories. Our inventories are valued at the lower of cost or market on a FIFO basis. Inventory costs include material, labor costs, and manufacturing overhead. Our excess and obsolete inventory reserve is based on both the current age of kit inventory as compared to its estimated life cycle and our forecasted product demand and production requirements for other inventory items for the next 36 months. Total charges incurred to write down excess and obsolete inventory to net realizable value included in “Cost of sales” were approximately $20.9 million , $19.2 million , and $21.5 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. During the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , our excess and obsolete charges included product rationalization initiative adjustments of $4.4 million , $3.1 million , and $4.1 million , respectively. Product liability claims and related insurance recoveries and other litigation. We are involved in legal proceedings involving product liability claims as well as contract, patent protection, and other matters. See Note 16 for additional information regarding product liability claims, product liability insurance recoveries, and other litigation. We make provisions for claims specifically identified for which we believe the likelihood of an unfavorable outcome is probable and the amount of loss can be estimated. For unresolved contingencies with potentially material exposure that are deemed reasonably possible, we evaluate whether a potential loss or range of loss can be reasonably estimated. Our evaluation of these matters is the result of a comprehensive process designed to ensure that recognition of a loss or disclosure of these contingencies is made in a timely manner. In determining whether a loss should be accrued or a loss contingency disclosed, we evaluate a number of factors including: the procedural status of each lawsuit; any opportunities for dismissal of the lawsuit before trial; the amount of time remaining before trial date; the status of discovery; the status of settlement; arbitration or mediation proceedings; and management’s estimate of the likelihood of success prior to or at trial. The estimates used to establish a range of loss and the amounts to accrue are based on previous settlement experience, consultation with legal counsel, and management’s settlement strategies. If the estimate of a probable loss is in a range and no amount within the range is more likely, we accrue the minimum amount of the range. We recognize legal fees as an expense in the period incurred. These expenses are reflected in either continuing or discontinued operations depending on the product associated with the claim. We record insurance recoveries from product liability insurance that is in force when they are realized or realizable, when we believe it is probable that the insurance carrier will settle the claim. Property, plant and equipment. Our property, plant and equipment is stated at cost. Depreciation, which includes amortization of assets under capital lease, is generally provided on a straight-line basis over the estimated useful lives generally based on the following categories: Land improvements 15 to 25 years Buildings and building improvements 10 to 40 years Machinery and equipment 3 to 14 years Furniture, fixtures and office equipment 3 to 14 years Surgical instruments 6 years Expenditures for major renewals and betterments, including leasehold improvements, that extend the useful life of the assets are capitalized and depreciated over the remaining life of the asset or lease term, if shorter. Maintenance and repair costs are charged to expense as incurred. Upon sale or retirement, the asset cost and related accumulated depreciation are eliminated from the respective accounts and any resulting gain or loss is included in income. Valuation of long-lived assets. Management periodically evaluates carrying values of long-lived assets, including property, plant and equipment and finite-lived intangible assets, when events and circumstances indicate that these assets may have been impaired. We account for the impairment of long-lived assets in accordance with FASB ASC 360 . Accordingly, we evaluate impairment of our long-lived assets based upon an analysis of estimated undiscounted future cash flows. If it is determined that a change is required in the useful life of an asset, future depreciation and amortization is adjusted accordingly. Alternatively, should we determine that an asset is impaired, an adjustment would be charged to income based on the difference between the asset’s fair market value and the asset's carrying value. Intangible assets and goodwill. Goodwill is recognized for the excess of the purchase price over the fair value of net assets of businesses acquired. FASB ASC 350-30-35-18 requires companies to evaluate for impairment intangible assets not subject to amortization, such as our IPRD assets, if events or changes in circumstances indicate than an asset might be impaired. Further, FASB ASC 350-20-35-30 requires companies to evaluate goodwill and intangibles not subject to amortization for impairment between annual impairment tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Unless circumstances otherwise dictate, the annual impairment test is performed on October 1 each year. See Note 8 for discussion of our 2018 goodwill impairment analysis. Our intangible assets with estimable useful lives are amortized on a straight-line basis over their respective estimated useful lives to their estimated residual values. This method of amortization approximates the expected future cash flow generated from their use. Finite-lived intangibles are reviewed for impairment in accordance with FASB ASC Section 360, Property, Plant and Equipment (FASB ASC 360). The weighted average amortization periods for our intangible assets are as follows: Completed technology 10 years Distribution channels 10 years Trademarks 5 years Licenses 11 years Customer relationships 17 years Non-compete agreements 4 years Other intangible assets 3 years Allowances for doubtful accounts. We experience credit losses on our accounts receivable; and accordingly, we must make estimates related to the ultimate collection of our accounts receivable. Specifically, we analyze our accounts receivable, historical bad debt experience, customer concentrations, customer creditworthiness, and current economic trends when evaluating the adequacy of our allowance for doubtful accounts. The majority of our accounts receivable are from hospitals and surgery centers. Our collection history has been favorable with minimal bad debts from these customers. We write-off accounts receivable when we determine that the accounts receivable are uncollectible, typically upon customer bankruptcy or the customer’s non-response to repeated collection efforts. Our allowance for doubtful accounts totaled $3.0 million and $ 4.3 million at December 30, 2018 and December 31, 2017 , respectively. Concentration of credit risk. Financial instruments that potentially subject us to concentrations of credit risk consist principally of accounts receivable. Management attempts to minimize credit risk by reviewing customers’ credit history before extending credit and by monitoring credit exposure on a regular basis. Collateral or other security is generally not required for accounts receivable. Concentrations of supply of raw material . We rely on a limited number of suppliers for the components used in our products. For certain human biologic products, such as Allomatrix ® , we depend on one supplier of demineralized bone matrix and cancellous bone matrix. We rely on two suppliers for our GRAFTJACKET ® family of soft tissue repair and graft containment products. Additionally, we have other soft tissue repair products for which we rely on one supplier, which include our ACTISHIELD™ and ACTISHIELD™ CF Amniotic Barrier Membranes and VIAFLOW™ and VIAFLOW™ C Flowable Placental Tissue Matrices. We maintain adequate stock from these suppliers in order to meet market demand . We rely on one supplier for a key component of our AUGMENT ® Bone Graft. In December 2013, our supplier notified us of its intent to terminate the supply agreement in December 2015. This supplier was contractually required to meet our supply requirements until the termination date, and to use commercially reasonable efforts to assist us in identifying a new supplier and support the transfer of technology and supporting documentation to produce this component. In April 2016, we entered into a commercial supply agreement with FUJIFILM Diosynth Biotechnologies U.S.A., Inc. pursuant to which Fujifilm agreed to manufacture and sell to us and we agreed to purchase the key component of our AUGMENT ® Bone Graft. Pursuant to our supply agreement with Fujifilm, commercial production of the key component is expected to begin in 2020. Although we believe that our current supply of the key component from our former supplier should be sufficient to last until after the component becomes available under the new agreement, no assurance can be provided that it will be sufficient. Income taxes. Income taxes are accounted for pursuant to the provisions of FASB ASC Section 740, Income Taxes (FASB ASC 740). Our effective tax rate is based on income by tax jurisdiction, statutory rates, and tax saving initiatives available to us in the various jurisdictions in which we operate. Significant judgment is required in determining our effective tax rate and evaluating our tax positions. This process includes assessing temporary differences resulting from differing recognition of items for income tax and financial accounting purposes. These differences result in deferred tax assets and liabilities, which are included within our consolidated balance sheet. The measurement of deferred tax assets is reduced by a valuation allowance if, based upon available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. See Note 11 for further discussion of our consolidated deferred tax assets and liabilities, and the associated valuation allowance. We provide for unrecognized tax benefits based upon our assessment of whether a tax position is “more-likely-than-not” to be sustained upon examination by the tax authorities. If a tax position meets the more-likely-than-not standard, then the related tax benefit is measured based on a cumulative probability analysis of the amount that is more-likely-than-not to be realized upon ultimate settlement or disposition of the underlying tax position. In December 2017, the United States enacted new legislation under the 2017 Tax Act. We recognized the income tax effects of the 2017 Tax Act in our 2017 financial statements in accordance with Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which allowed us to record provisional amounts under a one-year measurement period. We finalized our accounting for the provisions of the 2017 Tax Act in the fourth-quarter 2018 with no material impact on our financial statements. During 2018, we have adopted ASU 2018-02, Reclassification of Certain Income Tax Effects from Accumulated Other Comprehensive Income , issued in February 2018, allowing the reclassification of income tax effects of the 2017 Tax Act, referred to as “stranded tax effects” by FASB, from accumulated other comprehensive income (AOCI) to retained earnings. This adoption did not have a material impact on our financial statements. Other taxes. Taxes assessed by a governmental authority that are imposed concurrent with our revenue transactions with customers are presented on a net basis in our consolidated statements of operations. Revenue recognition. Our revenues are primarily generated through two types of customers, hospitals and surgery centers and stocking distributors, with the majority of our revenue derived from sales to hospitals and surgery centers. Our products are sold through a network of employee and independent sales representatives in the United States and by a combination of employee sales representatives, independent sales representatives, and stocking distributors outside the United States. We record revenues from sales to hospitals and surgery centers upon transfer of control of promised products in an amount that reflects the consideration we expect to receive in exchange for those products, which is generally when the product is surgically implanted in a patient. We record revenues from sales to our stocking distributors at a point in time upon transfer of control of promised products to the distributor. Our stocking distributors, who sell the products to their customers, take control of the products and assume all risks of ownership upon transfer. Our stocking distributors are obligated to pay us within specified terms regardless of when, if ever, they sell the products. In general, our stocking distributors do not have any rights of return or exchange; however, in limited situations, we have repurchase agreements with certain stocking distributors. Those certain agreements require us to repurchase a specified percentage of the inventory purchased by the distributor within a specified period of time prior to the expiration of the contract. During those specified periods, we defer the applicable percentage of the sales. An insignificant amount of sales related to these types of agreements was deferred and not yet recognized as revenue as of December 30, 2018 and December 31, 2017 . Shipping and handling costs . We incur shipping and handling costs associated with the shipment of goods to customers, independent distributors, and our subsidiaries. Amounts billed to customers for shipping and handling of products are included in net sales. Costs incurred related to shipping and handling of products to customers are included in selling, general and administrative expenses. Shipping and handling costs within selling, general and administrative expenses totaled $52.0 million , $49.4 million and $44.0 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. These amounts include instrument depreciation which totaled $28.4 million , $27.1 million , and $26.1 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. All other shipping and handling costs are included in cost of sales. Research and development costs. Research and development costs are charged to expense as incurred. Foreign currency translation. The financial statements of our subsidiaries whose functional currency is the local currency are translated into U.S. dollars using the exchange rate at the balance sheet date for assets and liabilities and the weighted average exchange rate for the applicable period for revenues, expenses, gains, and losses. Translation adjustments are recorded as a separate component of comprehensive loss in shareholders’ equity. Gains and losses resulting from transactions denominated in a currency other than the local functional currency are included in “Other expense (income), net” in our consolidated statements of operations. Comprehensive income. Comprehensive income is defined as the change in equity during a period related to transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners. The difference between our net loss and our comprehensive loss is attributable to foreign currency translation. Share-based compensation. We account for share-based compensation in accordance with FASB ASC Section 718, Compensation — Stock Compensation (FASB ASC 718). Under the fair value recognition provisions of FASB ASC 718, share-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense on a straight-line basis over the requisite service period, which is the vesting period. The determination of the fair value of share-based payment awards, such as options, on the date of grant using an option-pricing model is affected by our stock price, as well as assumptions regarding a number of complex and subjective variables, which include the expected life of the award, the expected stock price volatility over the expected life of the awards, expected dividend yield, and risk-free interest rate. The determination of the fair value of performance-based share-based payment awards, such as performance share units, is based on the estimated achievement of the established performance criteria on the date of grant and updated at the end of each reporting period until the performance period ends. Share-based compensation expense is only recognized for performance share units that we expect to vest, which we estimate based upon an assessment of the probability that the performance criteria will be achieved. We recorded share-based compensation expense of $26.1 million , $19.4 million , and $14.4 million during the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively, within our results of continuing operations. See Note 14 for further information regarding our share-based compensation assumptions and expenses. Derivative instruments. We account for derivative instruments and hedging activities under FASB ASC Section 815, Derivatives and Hedging (FASB ASC 815). Accordingly, all of our derivative instruments are recorded in the accompanying consolidated balance sheets as either an asset or liability and measured at fair value. The changes in the derivative’s fair value are recognized currently in earnings unless specific hedge accounting criteria are met. During 2016 and 2017, we employed a derivative program using foreign currency forward contracts to mitigate the risk of currency fluctuations on our intercompany receivable and payable balances that were denominated in foreign currencies. These forward contracts were expected to offset the transactional gains and losses on the related intercompany balances. These forward contracts were not designated as hedging instruments under FASB ASC 815. Accordingly, the changes in the fair value and the settlement of the contracts were recognized in the period incurred in the accompanying consolidated statements of operations. We discontinued our foreign currency forward contracts derivative program in 2018. We recorded a net loss of approximately $4.6 million and $0.8 million on our foreign currency contracts for the fiscal years ended December 31, 2017 and December 25, 2016 , respectively. These losses substantially offset translation gains recorded on our intercompany receivable and payable balances, and are also included in “Other (income) expense, net.” On February 13, 2015, May 20, 2016, and June 28, 2018, we issued the 2020 Notes, 2021 Notes, and 2023 Notes, respectively, as defined and described in Note 9 . The 2020 Notes Conversion Derivatives, 2021 Notes Conversion Derivatives, and 2023 Notes Conversion Derivatives each as defined and described in Note 6 , require bifurcation from the 2020 Notes, 2021 Notes, and 2023 Notes in accordance with ASC Topic 815, and are accounted for as derivative liabilities. We also entered into 2020, 2021, and 2023 Notes Hedges, as defined and described in Note 6 , in connection with the issuance of the 2020, 2021, and 2023 Notes. The 2020, 2021, and 2023 Notes Hedges, which are cash-settled, are intended to reduce our exposure to potential cash payments that we are required to make upon conversion of the 2020, 2021, and 2023 Notes in excess of the principal amount of converted notes if our ordinary share price exceeds the conversion price. The 2020, 2021, and 2023 Notes Hedges are accounted for as derivative assets in accordance with ASC Topic 815. Supplemental cash flow information. Cash paid for interest and income taxes was as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Interest $ 30,552 $ 24,641 $ 18,678 Income taxes $ 6,254 $ 7,359 $ 4,334 Recent Accounting Pronouncements. In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , and has subsequently issued several supplemental and/or clarifying ASUs (collectively ASC 606). Accounting Standards Codification (ASC) 606 prescribes a single common revenue standard that replaces most existing US GAAP revenue recognition guidance. ASC 606 outlines a five-step model, under which we recognize revenue as performance obligations within a customer contract are satisfied. ASC 606 is intended to provide more consistent interpretation and application of the principles outlined in the standard across filers in multiple industries and within the same industries compared to current practices, which should improve comparability. We adopted ASC 606 during 2018. Revenue is recognized at a point in time, generally upon surgical implantation or shipment of products to distributors. Therefore, adoption of ASC 606 did not have a material effect on our consolidated financial statements except for the additional disclosures included within Note 18. On February 25, 2016, the FASB issued ASU 2016-02, Leases , and has subsequently issued several supplemental and/or clarifying ASUs (collectively ASC 842). ASC 842 introduces a lessee model that brings most leases on the balance sheet. The new standard also aligns many of the underlying principles of the new lessor model with those in FASB ASC 606, the FASB’s new revenue recognition standard (e.g., those related to evaluating when profit can be recognized). Furthermore, ASC 842 addresses other concerns related to the current leases model. ASC 842 will be effective for us beginning in fiscal year 2019. We have evaluated the practical expedients and plan to adopt the hindsight practical expedient, the practical expedient for short-term leases, the practical expedient package which primarily limits the need for reassessing lease classification on existing leases, and to issue our financial statements showing comparative lease disclosures under current GAAP. We anticipate this adoption will add approximately $40 million on our consolidated balance sheet as of March 31, 2019 as a right of use asset and a right of use liability. We do not anticipate adoption will have a material impact on net earnings or cash flows. On August 29, 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40) to provide guidance on implementation costs incurred in a cloud computing arrangement (CCA) that is a service contract. Specifically, the ASU amends ASC 350 to include in its scope implementation costs of a CCA that is a service contract and clarifies that a customer should apply ASC 350-40, Internal Use Software , to determine which implementation costs should be capitalized in such a CCA. The ASU will be effective for us beginning in fiscal year 2020. We are in the initial phases of our adoption plans and, accordingly, we are unable to estimate any effect this may have on our consolidated financial statements.

Acquisitions (Notes)

Acquisitions (Notes)	12 Months Ended
	Dec. 30, 2018
Acquisitions [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions Cartiva, Inc. On October 10, 2018, we completed the acquisition of Cartiva, Inc. (Cartiva), an orthopaedic medical device company focused on treatment of osteoarthritis of the great toe. Under the terms of the agreement with Cartiva, we acquired 100% of the outstanding equity on a fully diluted basis of Cartiva for a total price of $435 million in cash, subject to certain adjustments which totaled $1.1 million , as set forth in the purchase agreement, $0.7 million of which was refunded in 2019. We funded the acquisition with the proceeds from a registered underwritten public offering of 18.2 million ordinary shares which had net proceeds of $423.0 million . See Note 13 for additional details related to the public offering. This acquisition adds a differentiated PMA approved technology for a high-volume foot and ankle procedure and further accelerates growth opportunities in our global extremities business. The results of operations of Cartiva is included in our consolidated financial statements for all periods after completion of the acquisition. The acquired business contributed net sales of $9.5 million and operating income of $2.4 million to our consolidated results of operations from the date of acquisition through December 30, 2018, which included $0.4 million of inventory step-up amortization and $1.9 million of intangible asset amortization. This operating income does not include the merger-related transaction costs discussed below. Merger-Related Transaction Costs In conjunction with the merger, we incurred approximately $6.5 million of merger-related transaction costs during the fiscal year ended December 30, 2018, which was recognized within selling, general and administrative expense in our consolidated statements of operations. These expenses primarily related to advisory fees, legal fees, and accounting and tax professional fees. Purchase Consideration and Net Assets Acquired The following presents the preliminary allocation of the purchase consideration to the assets acquired and liabilities assumed on October 10, 2018 (in thousands): Cash and cash equivalents $ 309 Accounts receivable 4,352 Inventories 2,686 Other current assets 486 Property, plant and equipment 1,446 Intangible assets 81,000 Total assets acquired 90,279 Current liabilities (4,226 ) Deferred income taxes (3,622 ) Total liabilities assumed (7,848 ) Net assets acquired $ 82,431 Goodwill 351,445 Total preliminary purchase consideration $ 433,876 The acquisition was recorded by allocating the costs of the net assets acquired based on their estimated fair values at the acquisition date. The fair values were based on management’s analysis, including work performed by third-party valuation specialists. Wright’s estimates and assumptions are subject to change during the measurement period (up to one year from the acquisition date) as we finalize our valuations of assets acquired and liabilities assumed in connection with the acquisition. The primary areas of the purchase price allocation that are not yet finalized relate to identifiable intangible assets and goodwill. Trade receivables and payables, as well as certain other current assets and property, plant and equipment, were valued at the existing carrying values as they approximated the fair value of those items at the acquisition date, based on management’s judgments and estimates. Trade receivables included gross contractual amounts of $5.8 million and our best estimate of $1.4 million which represented contractual cash flows not expected to be collected at the acquisition date. Inventory was recorded at estimated selling price less costs of disposal and a reasonable selling profit. The resulting inventory step-up adjustment is being recognized in cost of sales as the related inventory is sold. In determining the fair value of intangibles, we used an income method which is based on forecasts of the expected future cash flows attributable to the respective assets. Significant estimates and assumptions inherent in the valuations reflect a consideration of other marketplace participants and include the amount and timing of future cash flows (including expected growth rates and profitability), technology life cycles, customer attrition rates, and the discount rate applied to the cash flows. Of the $81.0 million of acquired intangible assets, $52.0 million was assigned to customer relationships ( 15 year life), $28.0 million was assigned to developed technology ( 7 year life), and $1.0 million was assigned to in-process research and development. The excess of the cost of the acquisition over the fair value of the net assets acquired is recorded as goodwill. The goodwill is primarily attributable to strategic opportunities that arose from the acquisition of Cartiva. The goodwill is not expected to be deductible for tax purposes. Pro Forma Condensed Combined Financial Information (Unaudited) The following unaudited pro forma combined financial information summarizes the results of operations for the periods indicated as if the Cartiva acquisition had been completed as of December 26, 2016, the beginning of Wright's fiscal year 2017. Pro forma information reflects adjustments that are expected to have a continuing impact on our results of operations and are directly attributable to the acquisition. The unaudited pro forma results include adjustments to reflect the amortization of the inventory step-up and the incremental intangible asset amortization to be incurred based on the preliminary values of each identifiable intangible asset. The pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisition had occurred as of December 26, 2016 or that may be obtained in the future, and do not reflect future synergies, integration costs, or other such costs or savings. Year ended December 30, 2018 Year ended December 31, 2017 Net sales $ 861,475 $ 769,111 Net loss from continuing operations (179,800 ) (68,722 ) The pro forma net loss for the year ended December 30, 2018 includes the following non-recurring items: $15.3 million of acquisition-related transaction expenses. IMASCAP On December 14, 2017, we completed the acquisition of IMASCAP, a leader in the development of software-based solutions for preoperative planning of shoulder replacement surgery. The intent of this transaction is to ensure exclusive access to breakthrough software enabling technology and patents to further differentiate our product portfolio and to further accelerate growth opportunities in our global extremities business. Under the terms of the agreement with IMASCAP, we acquired 100% of IMASCAP’s outstanding equity on a fully diluted basis for an initial payment of €52.9 million, or approximately $62.3 million , consisting of approximately €39.7 million, or approximately $46.7 million , in cash and approximately €13.2 million, or approximately $15.6 million , representing 661,753 Wright ordinary shares, payable at closing. Additionally, the purchase price included an estimated €15.1 million, or approximately $17.8 million , of contingent consideration related to the achievement of certain technical milestones and sales earnouts. The technical milestones involve the development and approval of a next generation reverse shoulder implant system and new software modules. The sales earnouts relate to certain guides and the next generation reverse shoulder implant system. Purchase Consideration and Net Assets Acquired The following presents the allocation of the purchase consideration to the assets acquired and liabilities assumed on December 14, 2017 (in thousands): Cash and cash equivalents $ 2,559 Accounts receivable 102 Other current assets 925 Property, plant and equipment 20 Intangible assets 10,865 Total assets acquired 14,471 Current liabilities (2,173 ) Long-term debt (886 ) Deferred income taxes (2,343 ) Total liabilities assumed (5,402 ) Net assets acquired $ 9,069 Goodwill 71,064 Total purchase consideration $ 80,133 The purchase consideration was allocated to the net assets acquired based on their estimated fair values at the acquisition date. The fair values were based on management’s analysis, including work performed by third-party valuation specialists. Operating assets and liabilities were valued at their existing carrying values as they approximated the fair value of those items at the acquisition date, based on management’s judgments and estimates. In determining the fair value of intangibles, we used an income method which is based on forecasts of the expected future cash flows attributable to the respective assets. Significant estimates and assumptions inherent in the valuations reflect a consideration of other marketplace participants and include the amount and timing of future cash flows (including expected growth rates and profitability), technology life cycles, and the discount rate applied to the cash flows. Of the $10.9 million of acquired intangible assets, $5.6 million was assigned to developed technology ( 6 year life) and $5.3 million was assigned to in-process research and development. The excess of the cost of the acquisition over the fair value of the net assets acquired is recorded as goodwill. The goodwill is primarily attributable to strategic opportunities that arose from the acquisition of IMASCAP. The goodwill is not expected to be deductible for tax purposes. During 2018, we revised opening balances acquired as a result of the IMASCAP acquisition, primarily for accounts receivable; other current assets; accrued expenses and other current liabilities; and deferred tax liabilities which resulted in a $0.9 million decrease in the preliminary value of goodwill determined as of December 14, 2017.

Discontinued Operations (Notes)

Discontinued Operations (Notes)	12 Months Ended
	Dec. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued Operations For the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , our loss from discontinued operations, net of tax, totaled $0.2 million , $137.7 million , and $267.4 million , respectively, and was attributable primarily to expenses associated with Wright's former OrthoRecon business and, to a lesser degree, the former Large Joints business. Large Joints Business On October 21, 2016, pursuant to a binding offer letter dated as of July 8, 2016, Tornier France, Corin, and certain other entities related to us and Corin entered into a business sale agreement and simultaneously completed and closed the sale of our Large Joints business. Pursuant to the terms of the agreement, we sold substantially all of the assets related to our Large Joints business to Corin for approximately €29.7 million in cash, less approximately €11.1 million for net working capital adjustments. Upon closing, the parties also executed a transitional services agreement and supply agreement, among other ancillary agreements required to implement the transaction. These agreements are on arm’s length terms and are not expected to be material to our consolidated financial statements. All historical operating results for the Large Joints business as well as continued involvement in accordance with the transitional service agreement and supply agreement are reflected within discontinued operations in the consolidated statements of operations. We recognized an impairment loss on assets held for sale of $21.3 million , before the effect of income taxes during 2016, based on the difference between the net carrying value of the assets and liabilities held for sale and the purchase price, less estimated adjustments and costs to sell. This loss was recorded within “Net loss from discontinued operations” in our consolidated statements of operations for the fiscal year ended December 25, 2016 . For the fiscal year ended December 30, 2018 , our loss from discontinued operations for the Large Joints business, net of tax, totaled $0.7 million and was primarily attributable to costs associated with transition services. For the fiscal year ended December 31, 2017 , our loss from discontinued operations for the Large Joints business, net of tax, totaled $4.1 million and was primarily attributable to professional fees and internal costs to support transition activities, costs associated with transition services and working capital adjustments. The following table summarizes the results of discontinued operations for the Large Joints business (in thousands) for the fiscal year ended December 25, 2016 : Fiscal year ended December 25, 2016 Net sales $ 35,318 Cost of sales 20,244 Selling, general and administrative 18,808 Loss from discontinued operations before income taxes (3,734 ) Impairment loss on assets held for sale, before income taxes 21,342 Total loss from discontinued operations before income taxes (25,076 ) Benefit for income taxes (5,615 ) Total loss from discontinued operations, net of tax $ (19,461 ) Cash provided by operating activities from the Large Joints business totaled $2.8 million for the fiscal year ended December 30, 2018 . Cash used in operating activities by the Large Joints business totaled $6.5 million for the fiscal year ended December 31, 2017 . Cash provided by operating activities and investing activities from the Large Joints business totaled $5.2 million and $20.7 million , respectively, for the fiscal year ended December 25, 2016. OrthoRecon Business On January 9, 2014, legacy Wright completed the divestiture and sale of its OrthoRecon business to MicroPort. Pursuant to the terms of the agreement, the purchase price (as defined in the agreement) was approximately $283.0 million (including a working capital adjustment), which MicroPort paid in cash. As a result of the transaction, we recognized approximately $24.3 million as the gain on disposal of the OrthoRecon business, before the effect of income taxes. Certain liabilities associated with the OrthoRecon business, including product liability claims associated with hip and knee products sold by legacy Wright prior to the closing, were not assumed by MicroPort. Charges associated with these product liability claims, including legal defense, settlements and judgments, income associated with product liability insurance recoveries, and changes to any contingent liabilities associated with the OrthoRecon business have been reflected within results of discontinued operations, and we will continue to reflect these within results of discontinued operations in future periods. All current and historical operating results for the OrthoRecon business are reflected within discontinued operations in the consolidated financial statements. The following table summarizes the results of discontinued operations for the OrthoRecon business (in thousands, except per share data): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Net sales $ — $ — $ — Selling, general and administrative (746 ) 135,235 247,978 Income (loss) from discontinued operations before income taxes 746 (135,235 ) (247,978 ) Provision (benefit) for income taxes 221 (1,707 ) — Total income (loss) from discontinued operations, net of tax $ 525 $ (133,528 ) $ (247,978 ) In 2018, charges associated with product liability claims from the OrthoRecon business were fully offset by insurance recoveries. As described within Note 16 , in September 2015, the third insurance carrier in the policy year applicable to titanium modular neck fracture claims denied coverage under its $25 million excess liability policy despite full payout by the other carriers in that policy year. We strongly disputed the carrier's position and, in accordance with the dispute resolution provisions of the policy, initiated an arbitration proceeding in London, England seeking payment of these funds. The arbitration proceeding was completed on February 15, 2018 and, on April 11, 2018, the arbitration tribunal issued its ruling. Thereafter, we and the insurance carrier agreed to resolve the entire matter in exchange for a single lump sum payment by the carrier to us in the amount of $30.75 million , representing the full policy limits of $25 million plus an additional $5.75 million for legal costs and interest. We received payment of this sum from the carrier on May 8, 2018 and have reflected this insurance recovery within our results of discontinued operations for 2018. During the fiscal years ended 2017 and 2016, the majority of our loss from discontinued operations was the result of our retained metal-on-metal product liability claims. During the fiscal years ended December 31, 2017 and December 25, 2016, we recognized charges, net of insurance proceeds, of $94.0 million , and $196.6 million respectively, within discontinued operations related to the retained metal-on-metal product liability claims associated with the OrthoRecon business (see Note 16 for additional discussion). We will incur continuing cash outflows associated with legal defense costs and the ultimate resolution of these contingent liabilities, net of insurance proceeds, until these liabilities are resolved. Cash used in operating activities by the OrthoRecon business totaled $91.4 million for the fiscal year ended December 30, 2018 and $221.6 million for the fiscal year ended December 31, 2017 . Cash provided by operating activities from the OrthoRecon business totaled $16.7 million for the fiscal year ended December 25, 2016, primarily due to the receipt of a $60 million insurance settlement, offset by legal defense costs and settlement of product liabilities.

Inventories

Inventories	12 Months Ended
	Dec. 30, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following (in thousands): December 30, 2018 December 31, 2017 Raw materials $ 9,612 $ 10,816 Work-in-process 26,839 28,581 Finished goods 144,239 128,747 $ 180,690 $ 168,144 Finished goods inventories held as of December 30, 2018 includes an inventory fair value step-up of $1.0 million related to the acquisition of Cartiva, which will be fully amortized in 2019. Total step-up related to the Cartiva acquisition was $1.4 million , of which $0.4 million was amortized in the fourth quarter of 2018.

Derivatives and Fair Value of F

Derivatives and Fair Value of Financial Instruments	12 Months Ended
	Dec. 30, 2018
Marketable Securities [Abstract]
Fair Value Disclosures [Text Block]	Fair Value of Financial Instruments and Derivatives We account for derivatives in accordance with FASB ASC 815, which establishes accounting and reporting standards requiring that derivative instruments be recorded on the balance sheet as either an asset or liability measured at fair value. Additionally, changes in the derivatives' fair value shall be recognized currently in earnings unless specific hedge accounting criteria are met. FASB ASC Section 820, Fair Value Measurements and Disclosures requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Financial instruments with unadjusted, quoted prices listed on active market exchanges. Level 2: Financial instruments determined using prices for recently traded financial instruments with similar underlying terms as well as directly or indirectly observable inputs, such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3: Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques. 2023 Notes Conversion Derivative and Notes Hedges On June 28, 2018, we issued $675 million aggregate principal amount of 1.625% cash exchangeable senior notes due 2023 (2023 Notes). See Note 9 of the condensed consolidated financial statements for additional information regarding the 2023 Notes. The 2023 Notes have a conversion derivative feature (2023 Notes Conversion Derivative) that requires bifurcation from the 2023 Notes in accordance with ASC Topic 815 and is accounted for as a derivative liability. The fair value of the 2023 Notes Conversion Derivative at the time of issuance of the 2023 Notes was $124.6 million . In connection with the issuance of the 2023 Notes, we entered into hedges (2023 Notes Hedges) with two option counterparties. The 2023 Notes Hedges, which are cash-settled, are generally intended to reduce our exposure to potential cash payments that we are required to make upon conversion of the 2023 Notes in excess of the principal amount of converted notes if our ordinary share price exceeds the conversion price. The aggregate cost of the 2023 Notes Hedges was $141.3 million and is accounted for as a derivative asset in accordance with ASC Topic 815. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to the 2023 Note Hedges, which may reduce the effectiveness of the 2023 Note Hedges. The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2023 Notes Hedges and 2023 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 2023 Notes Hedges Other assets $ 115,923 2023 Notes Conversion Derivative Other liabilities $ 116,833 The 2023 Notes Hedges and the 2023 Notes Conversion Derivative are measured at fair value using Level 3 inputs. These instruments are not actively traded and are valued using an option pricing model that uses observable and unobservable market data for inputs. Neither the 2023 Notes Conversion Derivative nor the 2023 Notes Hedges qualify for hedge accounting; thus, any changes in the fair value of the derivatives are recognized immediately in our consolidated statements of operations. The following table summarizes the net (loss) gain on changes in fair value (in thousands) related to the 2023 Notes Hedges and 2023 Notes Conversion Derivative: Fiscal year ended December 30, 2018 2023 Notes Hedges $ (25,355 ) 2023 Notes Conversion Derivative 7,792 Net loss on changes in fair value $ (17,563 ) In February 2019, we issued $139.6 million additional aggregate principal amount of the 2023 Notes in exchange for $130.1 million aggregate principal amount of the 2020 Notes and settled a pro rata share of the 2020 Notes Conversion Derivatives, 2020 Notes Hedges and warrants corresponding to the amount of 2020 Notes exchanged pursuant to this exchange. We also entered into additional agreements for 2023 Notes Conversion Derivatives, 2023 Notes Hedges, and warrants. See Note 19 for additional information about this transaction. 2021 Notes Conversion Derivative and Notes Hedges On May 20, 2016, we issued $395 million aggregate principal amount of 2.25% 2021 Notes. See Note 9 of the consolidated financial statements for additional information regarding the 2021 Notes. The 2021 Notes have a conversion derivative feature (2021 Notes Conversion Derivative) that requires bifurcation from the 2021 Notes in accordance with ASC Topic 815, and is accounted for as a derivative liability. The fair value of the 2021 Notes Conversion Derivative at the time of issuance of the 2021 Notes was $117.2 million . In connection with the issuance of the 2021 Notes, we entered into hedges (2021 Notes Hedges) with two option counterparties. The 2021 Notes Hedges, which are cash-settled, are generally intended to reduce our exposure to potential cash payments that we are required to make upon conversion of the 2021 Notes in excess of the principal amount of converted notes if our ordinary share price exceeds the conversion price. The aggregate cost of the 2021 Notes Hedges was $99.8 million and is accounted for as a derivative asset in accordance with ASC Topic 815. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to the 2021 Note Hedges, which may reduce the effectiveness of the 2021 Note Hedges. The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2021 Notes Hedges and 2021 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 December 31, 2017 2021 Notes Hedges Other assets $ 188,301 $ 127,063 2021 Notes Conversion Derivative Other liabilities $ 187,539 $ 126,148 In the third fiscal quarter of 2018, the closing price of our ordinary shares was greater than 130% of the 2021 Notes conversion price for 20 or more of the 30 consecutive trading days preceding the quarter-end; and, therefore, the holders of the 2021 Notes had the ability to convert the notes during the succeeding quarterly period. Due to the ability of the holders of the 2021 Notes to convert the notes during this period, the carrying value of the 2021 Notes and the fair value of the 2021 Notes Conversion Derivative were classified as current liabilities, and the fair value of the 2021 Notes Hedges were classified as current assets as of September 30, 2018. There were no conversions during the fourth quarter of 2018. The closing price of our ordinary shares was less than 130% of the 2021 Notes conversion price for more than 20 of the 30 consecutive trading days preceding the calendar fiscal quarter ended December 30, 2018, which resulted in the 2021 Notes no longer being convertible. As such, the 2021 Notes, 2021 Notes Conversion Derivative and 2021 Notes Hedges were classified as long-term as of December 30, 2018. The 2021 Notes Hedges and the 2021 Notes Conversion Derivative are measured at fair value using Level 3 inputs. These instruments are not actively traded and are valued using an option pricing model that uses observable and unobservable market data for inputs. Neither the 2021 Notes Conversion Derivative nor the 2021 Notes Hedges qualify for hedge accounting; thus, any changes in the fair value of the derivatives is recognized immediately in the consolidated statements of operations. The following table summarizes the net gain (loss) on changes in fair value (in thousands) related to the 2021 Notes Hedges and 2021 Notes Conversion Derivative: Fiscal year ended December 30, 2018 December 31, 2017 2021 Notes Hedges $ 61,238 $ (32,032 ) 2021 Notes Conversion Derivative (61,391 ) 35,453 Net (loss)/gain on changes in fair value $ (153 ) $ 3,421 2020 Notes Conversion Derivative and Notes Hedges On February 13, 2015, WMG issued $632.5 million aggregate principal amount of 2.00% cash convertible senior notes due 2020 (2020 Notes). See Note 9 of the consolidated financial statements for additional information regarding the 2020 Notes. The 2020 Notes have a conversion derivative feature (2020 Notes Conversion Derivative) that requires bifurcation from the 2020 Notes in accordance with ASC Topic 815, and is accounted for as a derivative liability. The fair value of the 2020 Notes Conversion Derivative at the time of issuance of the 2020 Notes was $149.8 million . In connection with the issuance of the 2020 Notes, WMG entered into hedges (2020 Notes Hedges) with three option counterparties. The 2020 Notes Hedges, which are cash-settled, are generally intended to reduce WMG's exposure to potential cash payments that WMG is required to make upon conversion of the 2020 Notes in excess of the principal amount of converted notes if our ordinary share price exceeds the conversion price. The aggregate cost of the 2020 Notes Hedges was $144.8 million and is accounted for as a derivative asset in accordance with ASC Topic 815. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to the 2020 Note Hedges, which may reduce the effectiveness of the 2020 Note Hedges. Concurrently with the issuance and sale of the 2021 Notes, certain holders of the 2020 Notes exchanged approximately $45 million aggregate principal amount of 2020 Notes (including the 2020 Notes Conversion Derivative) for the 2021 Notes. For each $1,000 principal amount of 2020 Notes validly submitted for exchange, we delivered $990.00 principal amount of the 2021 Notes (subject, in each case, to rounding down to the nearest $1,000 principal amount of the 2021 Notes, the difference being referred as the rounded amount) to the investor plus an amount of cash equal to the unpaid interest on the 2020 Notes and the rounded amount at an aggregate cost of approximately $44.6 million . We settled the associated portion of the 2020 Notes Conversion Derivative at a benefit of approximately $0.4 million and satisfied the accrued interest, which was not material. In addition, during the second quarter of 2016, we settled a portion of the 2020 Notes Hedges (receiving $3.9 million ) and repurchased a portion of the warrants associated with the 2020 Notes (paying $3.3 million ), generating net proceeds of approximately $0.6 million . Concurrently with the issuance and sale of the 2023 Notes, certain holders of the 2020 Notes exchanged approximately $400.9 million aggregate principal amount of their 2020 Notes for the 2023 Notes. For each $1,000 principal amount of 2020 Notes validly submitted for exchange, we delivered $1,138.70 principal amount of the 2023 Notes (subject to rounding down to the nearest $1,000 principal amount of the 2023 Notes for each exchanging investor, the difference being referred as the rounded amount) to the investor. As part of this exchange we settled a pro rata portion of the 2020 Notes Conversion Derivative for $55.6 million . During the second quarter of 2018, we agreed to settle a pro rata portion of the 2020 Notes Hedges. We also agreed to repurchase a pro rata portion of the warrants associated with the 2020 Notes (2020 Warrants Derivative) and recorded a derivative liability which had a fair value of $27.3 million as of June 28, 2018. Prior to this agreement, the warrants were recorded within shareholders' equity as, at that time, the warrants were expected to be net-share settled. The pricing of the settled portion of the 2020 Notes Hedges and 2020 Warrants Derivative was based on the volume-weighted average price of our stock price during July 9, 2018 and July 27, 2018, the unwind period. On July 30, 2018, we received proceeds of approximately $34.6 million related to the 2020 Notes Hedges and paid $24.0 million related to the 2020 Warrants Derivative, generating net proceeds of $10.6 million . The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2020 Notes Hedges and 2020 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 Location on consolidated balance sheet December 31, 2017 2020 Notes Hedges Other current assets $ 17,822 Other assets $ 45,033 2020 Notes Conversion Derivative Accrued expenses and other current liabilities $ 17,386 Other liabilities $ 44,132 The holders of the 2020 Notes may convert their notes at any time prior to August 15, 2019 solely into cash upon satisfaction of certain circumstances as described in Note 9 . On or after August 15, 2019, holders may convert their 2020 Notes solely into cash, regardless of the foregoing circumstances. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes and the fair value of the 2020 Notes Conversion Derivatives were classified as current liabilities and the fair value of the 2020 Notes Hedges was classified as current assets as of December 30, 2018. The respective balances were all classified as long-term as of December 31, 2017. The 2020 Notes Hedges and the 2020 Notes Conversion Derivative are measured at fair value using Level 3 inputs. These instruments are not actively traded and are valued using an option pricing model that uses observable and unobservable market data for inputs. Neither the 2020 Notes Conversion Derivative nor the 2020 Notes Hedges qualify for hedge accounting; thus, any change in the fair value of the derivatives is recognized immediately in the consolidated statements of operations. The following table summarizes the net gain (loss) on changes in fair value (in thousands) related to the 2020 Notes Hedges, 2020 Warrants Derivative and 2020 Notes Conversion Derivative: Fiscal year ended December 30, 2018 December 31, 2017 2020 Notes Hedges $ 7,342 $ (32,199 ) 2020 Warrants Derivative 3,336 — 2020 Notes Conversion Derivative (28,897 ) 33,626 Net (loss)/gain on changes in fair value $ (18,219 ) $ 1,427 In February 2019, we issued $139.6 million additional aggregate principal amount of the 2023 Notes in exchange for $130.1 million aggregate principal amount of the 2020 Notes and settled a pro rata share of the 2020 Notes Conversion Derivatives, 2020 Notes Hedges and warrants corresponding to the amount of 2020 Notes exchanged pursuant to this exchange. We also entered into additional agreements for 2023 Notes Conversion Derivatives, 2023 Notes Hedges, and warrants. See Note 19 for additional information about this transaction. 2017 Notes Conversion Derivative and Notes Hedges On August 31, 2012, WMG issued $300 million aggregate principal amount of 2.00% cash convertible senior notes due 2017 (the 2017 Notes). The 2017 Notes matured, and the remaining $2.0 million principal amount was repaid on August 15, 2017. See Note 9 of the consolidated financial statements for additional information regarding the 2017 Notes. The 2017 Notes had a conversion derivative feature (2017 Notes Conversion Derivative) that required bifurcation from the 2017 Notes in accordance with ASC Topic 815, and was accounted for as a derivative liability. The fair value of the 2017 Notes Conversion Derivative at the time of issuance of the 2017 Notes was $48.1 million . In connection with the issuance of the 2017 Notes, WMG entered into hedges (2017 Notes Hedges) with three option counterparties. The aggregate cost of the 2017 Notes Hedges was $56.2 million and was accounted for as a derivative asset in accordance with ASC Topic 815. In connection with the issuance of the 2020 Notes, WMG used approximately $292 million of the 2020 Notes' net proceeds to repurchase and extinguish approximately $240 million aggregate principal amount of the 2017 Notes, settle the associated portion of the 2017 Notes Conversion Derivative at a cost of approximately $49 million , and satisfy the accrued interest of $2.4 million . WMG also settled all of the 2017 Notes Hedges in February 2015 when the 2020 Notes were issued (receiving $70 million ) and repurchased all of the warrants associated with the 2017 Notes (paying $60 million ), generating net proceeds of approximately $10 million . Concurrently with the issuance and sale of the 2021 Notes, certain holders of the 2017 Notes exchanged approximately $54.4 million aggregate principal amount of 2017 Notes (including the 2017 Notes Conversion Derivative) for the 2021 Notes. For each $1,000 principal amount of 2017 Notes validly submitted for exchange, we delivered $1,035.40 principal amount of the 2021 Notes (subject, in each case, to rounding down to the nearest $1,000 principal amount of the 2021 Notes, the difference being referred as the rounded amount) to the investor plus an amount of cash equal to the unpaid interest on the 2017 Notes and the rounded amount at a cost of approximately $56.3 million . We settled the associated portion of the 2017 Notes Conversion Derivative at a cost of approximately $1.9 million and satisfied the accrued interest, which was not material. In addition, during the second quarter of 2016, we repurchased and extinguished an additional $3.6 million aggregate principal amount of the 2017 Notes in privately negotiated transactions and settled the associated portion of the 2017 Notes Conversion Derivative at a cost of approximately $0.1 million , and satisfied the accrued interest, which was not material. The remainder of the 2017 Notes Conversion Derivative was settled at a cost of approximately $0.2 million in conjunction with the maturity of the 2017 Notes on August 15, 2017. The 2017 Notes Conversion Derivative did not qualify for hedge accounting; thus, any change in the fair value of the derivative was recognized immediately in our consolidated statements of operations. The changes in fair value related to the 2017 Notes Conversion Derivative was immaterial in 2017. To determine the fair value of the embedded conversion option in the 2020, 2021, and 2023 Notes Conversion Derivatives, a trinomial lattice model was used. A trinomial stock price lattice model generates three possible outcomes of stock price - one up, one down, and one stable. This lattice generates a distribution of stock prices at the maturity date and throughout the life of the 2020, 2021, and 2023 Notes. Using this stock price lattice, a convertible note lattice was created where the value of the embedded conversion option was estimated by comparing the value produced in a convertible note lattice with the option to convert against the value without the ability to convert. In each case, the convertible note lattice first calculates the possible convertible note values at the maturity date, using the distribution of stock prices, which equals to the maximum of (x) the remaining bond cash flows and (y) stock price times the conversion price. The values of the 2020, 2021, and 2023 Notes Conversion Derivatives at the valuation date were estimated using the values at the maturity date and moving back in time on the lattices (both for the lattice with the conversion option and without the conversion option). Specifically, at each node, if the 2020, 2021, or 2023 Notes are eligible for early conversion, the value at this node is the maximum of (i) converting to stock, which is the stock price times the conversion price, and (ii) holding onto the 2020, 2021, and 2023 Notes, which is the discounted and probability-weighted value from the three possible outcomes at the future nodes plus any accrued but unpaid coupons that are not considered at the future nodes. If the 2020, 2021, or 2023 Notes are not eligible for early conversion, the value of the conversion option at this node equals to (ii). In the lattice, a credit adjustment was applied to the discount for each cash flow in the model as the embedded conversion option, as well as the coupon and notional payments, is settled with cash instead of shares. To estimate the fair value of the 2020, 2021, and 2023 Notes Hedges, we used the Black-Scholes formula combined with credit adjustments, as the option counterparties have credit risk and the call options are cash settled. We assumed that the call options will be exercised at the maturity since our ordinary shares do not pay any dividends and management does not expect to declare dividends in the near term. The following assumptions were used in the fair market valuations as of December 30, 2018 : 2020 Notes Conversion Derivative 2020 Notes Hedge 2021 Notes Conversion Derivative 2021 Notes 2023 Notes Conversion Derivative 2023 Notes Hedge Black Stock Volatility 1 34.48% 34.48% 42.2% 42.2% 31.9% 31.9% Credit Spread for Wright 2 4.67% N/A 4.50% N/A 3.72% N/A Credit Spread for Deutsche Bank AG 3 N/A 1.38% N/A N/A N/A N/A Credit Spread for Wells Fargo Securities, LLC 3 N/A 0.25% N/A N/A N/A N/A Credit Spread for JPMorgan Chase Bank 3 N/A 0.3% N/A 0.45% N/A 0.56% Credit Spread for Bank of America 3 N/A N/A N/A 0.46% N/A 0.59% 1 Volatility selected based on historical and implied volatility of ordinary shares of Wright Medical Group N.V. 2 Credit spread implied from traded price. 3 Credit spread of each bank is estimated using CDS curves. Source: Bloomberg. The fair value of our notes conversion derivatives is determined using a trinomial lattice model and is classified in Level 3. The fair value of our notes hedges is determined using the Black-Scholes formula combined with credit adjustments and is classified in Level 3. We used a black stock volatility, which is one of the most significant assumptions, of 34.48% , 42.2% , and 31.9% in calculating the fair value of our 2020, 2021, and 2023 Notes Conversion Derivatives and Notes Hedges, respectively, as of December 30, 2018 . The change in the fair value of Notes Conversion Derivatives resulting from a change in the black stock volatility would have a direct impact on net profit, with an increase in volatility resulting in an increase in the net loss and a decrease in volatility resulting in a decrease in the net loss for the period. The change in the fair value of Notes Hedges resulting from a change in the black stock volatility would have an indirect impact on net profit, with an increase in volatility resulting in a decrease in the net loss and a decrease in volatility resulting in an increase in the net loss for the period. The impact on profit due to volatility of Notes Hedges would be offset by a similar change in volatility of the Notes Conversion Derivatives. Derivatives not Designated as Hedging Instruments During 2017 and 2016, we employed a derivative program using foreign currency forward contracts to mitigate the risk of currency fluctuations on our intercompany receivable and payable balances that are denominated in foreign currencies. These forward contracts were expected to offset the transactional gains and losses on the related intercompany balances. These forward contracts were not designated as hedging instruments under FASB ASC Topic 815. Accordingly, the changes in the fair value and the settlement of the contracts were recognized in the period incurred in the accompanying condensed consolidated statements of operations. During the quarter ended April 1, 2018, we discontinued our foreign currency forward contracts derivative program. At December 30, 2018 and December 31, 2017 , we had no foreign currency contracts outstanding. As part of our acquisition of WG Healthcare on January 7, 2013, we were obligated to pay contingent consideration upon the achievement of certain revenue milestones. As of December 25, 2016, we recorded an estimated fair value of future consideration of $17.8 million which was paid during 2017. As a result of the acquired sales and distribution business of Surgical Specialties Australia Pty. Ltd in 2015, we recorded the estimated fair value of future contingent consideration of approximately $0.9 million as of December 31, 2017 which was paid during the quarter ended April 1, 2018. As a result of the acquired business of IMASCAP in 2017, we recorded the estimated fair value of future contingent consideration of approximately €16.7 million and €15.1 million , or approximately $19.2 million and $17.8 million , related to the achievement of certain technical milestones and sales earnouts as of December 30, 2018 and December 31, 2017 , respectively. The estimated fair value of contingent consideration related to technical milestones totaled $12.7 million and $11.9 million as of December 30, 2018 and December 31, 2017 , respectively, and is contingent upon the development and approval of a next generation reverse shoulder implant system and new software modules. The estimated fair value of contingent consideration related to sales earnouts totaled $6.5 million and $5.9 million as of December 30, 2018 and December 31, 2017 , respectively, and is contingent upon the sale of certain guides and the next generation reverse shoulder implant system. The fair values of the sales earn out contingent consideration as of December 30, 2018 and December 31, 2017 were determined using a discounted cash flow model and probability adjusted estimates of the future earnings and is classified in Level 3. The discount rate is 12% for IMASCAP. The contingent consideration from the IMASCAP acquisition related to technical milestones is based on meeting certain developmental milestones for new software modules and for the FDA and CE clearance for the next generation reverse shoulder implant system. The fair value of this contingent consideration as of December 30, 2018 and December 31, 2017 was determined using probability adjusted estimates of the future payments and is classified in Level 3. The discount rate is approximately 6% for IMASCAP. A change in the discount rate would have limited impact on our profits or the fair value of this contingent consideration. Changes in the fair value of contingent consideration are recorded in “Other expense (income), net” in our consolidated statements of operations. On March 1, 2013, as part of our acquisition of BioMimetic Therapeutics, Inc. (BioMimetic), we issued Contingent Value Rights (CVRs) as part of the merger consideration. Each CVR entitles its holder to receive additional cash payments of up to $6.50 per share, which are payable upon receipt of FDA approval of AUGMENT ® Bone Graft and upon achieving certain revenue milestones. On September 1, 2015, AUGMENT ® Bone Graft received FDA approval and the first of the milestone payments associated with the CVRs was paid out at $3.50 per share, which totaled $98.1 million . The fair value of the CVRs outstanding at December 30, 2018 and December 31, 2017 was $0.4 million and $42.3 million , respectively, and was determined using the closing price of the security in the active market (Level 1). The change in the fair value of the CVRs resulted in an insignificant amount of expense in the fiscal year ended December 30, 2018 and $5.3 million of expense in the fiscal year ended December 31, 2017 . The income or expense related to the change in the fair value of the CVRs is recorded in “Other expense (income), net” in our consolidated statements of operations. If, prior to March 1, 2019, sales of AUGMENT ® Bone Graft reach $40 million over 12 consecutive months, cash payment would be required at $1.50 per share, or $42 million . This milestone was met and paid out during 2018. Further, if, prior to March 1, 2019, sales of AUGMENT ® Bone Graft reach $70 million over 12 consecutive months, an additional cash payment would be required at $1.50 per share, or $42 million. As of December 30, 2018 , we have reflected the $0.4 million balance related to CVR liability within “Accrued expenses and other current liabilities.” The carrying value of cash and cash equivalents, accounts receivable, and accounts payable approximates the fair value of these financial instruments at December 30, 2018 and December 31, 2017 due to their short maturities and variable rates. The following tables summarize the valuation of our financial instruments (in thousands): Total Quoted prices in active markets (Level 1) Prices with other observable inputs (Level 2) Prices with unobservable inputs (Level 3) At December 30, 2018 Assets Cash and cash equivalents $ 191,351 $ 191,351 $ — $ — 2020 Notes Hedges 17,822 — — 17,822 2021 Notes Hedges 188,301 — — 188,301 2023 Notes Hedges 115,923 — — 115,923 Total $ 513,397 $ 191,351 $ — $ 322,046 Liabilities 2020 Notes Conversion Derivative $ 17,386 $ — $ — $ 17,386 2021 Notes Conversion Derivative 187,539 — — 187,539 2023 Notes Conversion Derivative 116,833 — — 116,833 Contingent consideration 19,248 — — 19,248 Contingent consideration (CVRs) 420 420 — — Total $ 341,426 $ 420 $ — $ 341,006 Total Quoted prices in active markets (Level 1) Prices with other observable inputs (Level 2) Prices with unobservable inputs (Level 3) At December 31, 2017 Assets Cash and cash equivalents $ 167,740 $ 167,740 $ — $ — 2020 Notes Hedges 45,033 — — 45,033 2021 Notes Hedges 127,063 — — 127,063 Total $ 339,836 $ 167,740 $ — $ 172,096 Liabilities 2020 Notes Conversion Derivative $ 44,132 $ — $ — $ 44,132 2021 Notes Conversion Derivative 126,148 — — 126,148 Contingent consideration 19,188 — — 19,188 Contingent consideration (CVRs) 42,325 42,325 — — Total $ 231,793 $ 42,325 $ — $ 189,468 The following is a roll forward of our assets and liabilities measured at fair value (in thousands) on a recurring basis using unobservable inputs (Level 3) (in thousands): Balance at December 31, 2017 Additions Transfers into Level 3 Gain/(loss) included in earnings Settlements Currency Balance at December 30, 2018 2020 Notes Hedges 45,033 — — 7,342 (34,553 ) — 17,822 2020 Notes Conversion Derivative (44,132 ) — — (28,897 ) 55,643 — (17,386 ) 2020 Warrants Derivative — (27,308 ) — 3,336 23,972 — — 2021 Notes Hedges 127,063 — — 61,238 — — 188,301 2021 Notes Conversion Derivative (126,148 ) — — (61,391 ) — — (187,539 ) 2023 Notes Hedges — 141,278 — (25,355 ) — — 115,923 2023 Notes Conversion Derivative — (124,625 ) — 7,792 — — (116,833 ) Contingent consideration (19,188 ) — — (1,789 ) 919 810 (19,248 )

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 30, 2018
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment, net consists of the following (in thousands): December 30, 2018 December 31, 2017 Land and land improvements $ 2,127 $ 2,163 Buildings 43,087 41,537 Machinery and equipment 82,445 60,859 Furniture, fixtures and office equipment 161,614 142,299 Construction in progress 14,113 14,403 Surgical instruments 230,980 187,660 534,366 448,921 Less: Accumulated depreciation (309,437 ) (236,542 ) $ 224,929 $ 212,379 The components of property, plant and equipment recorded under capital leases consist of the following (in thousands): December 30, 2018 December 31, 2017 Buildings $ 12,017 $ 15,530 Machinery and equipment 24,331 12,478 Furniture, fixtures and office equipment 559 960 36,907 28,968 Less: Accumulated depreciation (11,906 ) (7,749 ) $ 25,001 $ 21,219 Depreciation expense recognized within results of continuing operations approximated $59.5 million , $56.8 million , and $55.8 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively, and included depreciation of assets under capital leases.

Goodwill and Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles Changes in the carrying amount of goodwill occurring during the fiscal years ended December 31, 2017 and December 30, 2018 , are as follows (in thousands): U.S. Lower Extremities U.S. Upper Extremities International Extremities Total Goodwill at December 25, 2016 $ 218,525 $ 558,669 $ 73,848 $ 851,042 Goodwill associated with IMASCAP acquisition — 71,981 — 71,981 Foreign currency translation — — 10,639 10,639 Goodwill at December 31, 2017 $ 218,525 $ 630,650 $ 84,487 $ 933,662 Goodwill associated with Cartiva acquisition 351,445 — — 351,445 Goodwill adjustment associated with IMASCAP acquisition — (917 ) — (917 ) Foreign currency translation — (1,883 ) (13,353 ) (15,236 ) Goodwill at December 30, 2018 $ 569,970 $ 627,850 $ 71,134 $ 1,268,954 On October 10, 2018, we completed the acquisition of Cartiva. As part of the preliminary purchase price allocation, we acquired $81.0 million of intangible assets related to completed technology, in-process research and development, and customer relationships and $351.4 million of goodwill. Of the $81.0 million of acquired intangible assets, $52.0 million was assigned to customer relationships ( 15 year life), $28.0 million was assigned to developed technology ( 7 year life), and $1.0 million was assigned to in-process research and development. On December 14, 2017, we completed the acquisition of IMASCAP. As part of the preliminary purchase price allocation, we acquired $10.9 million of intangible assets related to completed technology and in-process research and development and $72.0 million of goodwill. Of the $10.9 million of acquired intangible assets, $5.6 million was assigned to developed technology ( 6 year life) and $5.3 million was assigned to in-process research and development. During the nine months ended September 30, 2018, we revised opening balances acquired as a result of the IMASCAP acquisition, primarily for accounts receivable; other current assets; accrued expenses and other current liabilities; and deferred tax liabilities, which resulted in a $0.9 million decrease in the preliminary value of goodwill determined as of December 14, 2017. See Note 3 for additional discussion of these adjustments. Goodwill is recognized for the excess of the purchase price over the fair value of net assets of businesses acquired. Goodwill is required to be tested for impairment at least annually. As of October 1, 2018 , we performed a qualitative analysis to test goodwill for impairment and determined that it is not more likely than not that the carrying value of our U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics reporting units exceeded their respective fair values, indicating that goodwill was not impaired. The components of our identifiable intangible assets, net are as follows (in thousands): December 30, 2018 December 31, 2017 Cost Accumulated amortization Cost Accumulated amortization Indefinite life intangibles: IPRD technology $ 6,262 $ 6,422 Finite life intangibles: Distribution channels 250 $ 250 900 $ 640 Completed technology 174,596 55,114 149,645 40,810 Licenses 6,547 1,851 5,268 1,530 Customer relationships 179,605 30,935 129,693 23,268 Trademarks 14,048 11,564 14,368 10,487 Non-compete agreements 3,252 2,514 3,964 2,603 Other 514 514 569 490 Total finite life intangibles 378,812 $ 102,742 304,407 $ 79,828 Total intangibles 385,074 310,829 Less: Accumulated amortization (102,742 ) (79,828 ) Intangible assets, net $ 282,332 $ 231,001 Based on the total finite life intangible assets held at December 30, 2018 , we expect to amortize approximately $30.2 million in 2019 , $29.5 million in 2020 , $29.3 million in 2021 , $29.3 million in 2022 , and $29.2 million in 2023 .

Long-Term Debt and Capital Leas

Long-Term Debt and Capital Lease Obligations	12 Months Ended
	Dec. 30, 2018
Long-term Debt and Capital Lease Obligations [Abstract]
Long Term Debt and Capital Lease Obligations	Debt and Capital Lease Obligations Debt and capital lease obligations consist of the following (in thousands): December 30, 2018 December 31, 2017 Capital lease obligations $ 25,539 $ 20,401 2023 Notes 548,076 — 2021 Notes 321,286 300,051 2020 Notes 1 173,533 513,014 Term Loan Facility 18,979 — Asset-based line of credit 17,761 53,645 Other debt 9,953 8,003 1,115,127 895,114 Less: current portion 1 (201,686 ) (58,906 ) $ 913,441 $ 836,208 _____________________ 1 The holders of the 2020 Notes may convert their notes at any time prior to August 15, 2019 solely into cash upon satisfaction of certain circumstances as described below. On or after August 15, 2019, holders may convert their 2020 Notes solely into cash, regardless of the foregoing circumstances. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes were classified as current liabilities as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017. 2023 Notes On June 28, 2018 , WMG issued $675 million aggregate principal amount of the 2023 Notes pursuant to an indenture (2023 Notes Indenture), dated as of June 28, 2018 , with The Bank of New York Mellon Trust Company, N.A., as trustee. The 2023 Notes are fully and unconditionally guaranteed by us on a senior unsecured basis. The 2023 Notes require interest to be paid at an annual rate of 1.625% semi-annually in arrears on each June 15 and December 15 and will mature on June 15, 2023 unless earlier converted or repurchased. The 2023 Notes are convertible, subject to certain conditions, solely into cash. The initial conversion rate for the 2023 Notes is 29.9679 ordinary shares (subject to adjustment as provided in the 2023 Notes Indenture) per $1,000 principal amount of the 2023 Notes (subject to, and in accordance with, the settlement provisions of the 2023 Notes Indenture), which is equal to an initial conversion price of approximately $33.37 per ordinary share. WMG may not redeem the 2023 Notes prior to the maturity date, and no “sinking fund” is available for the 2023 Notes, which means that WMG is not required to redeem or retire the 2023 Notes periodically. The holders of the 2023 Notes may convert their 2023 Notes at any time prior to the close of business on the business day immediately preceding December 15, 2022 solely into cash, in multiples of $1,000 principal amount, upon satisfaction of one or more of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2018 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of 2023 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On or after December 15, 2022 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2023 Notes solely into cash, regardless of the foregoing circumstances. Upon conversion, a holder will receive an amount in cash, per $1,000 principal amount of the 2023 Notes, equal to the settlement amount as calculated under the 2023 Notes Indenture. If a fundamental change, as defined in the 2023 Notes Indenture, occurs, subject to certain conditions, holders of the 2023 Notes will have the option to require WMG to repurchase for cash all or a portion of their 2023 Notes at a repurchase price equal to 100% of the principal amount of the 2023 Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date, as defined in the 2023 Notes Indenture. In addition, following a make-whole fundamental change, as defined in the 2023 Notes Indenture, that occurs prior to the maturity date, WMG, under certain circumstances, will increase the applicable conversion rate for a holder that elects to convert its 2023 Notes in connection with such make-whole fundamental change. Our guarantee of the 2023 Notes is our senior unsecured obligation that ranks: (i) senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the guarantee; (ii) equal in right of payment to any of our unsecured indebtedness that is not so subordinated; (iii) effectively junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness; and (iv) structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. As a result of the issuance of the 2023 Notes, we recorded deferred financing charges of approximately $13.5 million , which are being amortized over the term of the 2023 Notes using the effective interest method. During the fiscal year ended December 30, 2018, we recorded $1.1 million of interest expense related to the amortization of the deferred financing costs. The 2023 Notes Conversion Derivative requires bifurcation from the 2023 Notes in accordance with ASC Topic 815, Derivatives and Hedging , and is accounted for as a derivative liability. See Note 6 for additional information regarding the 2023 Notes Conversion Derivative. The fair value of the 2023 Notes Conversion Derivative at the time of issuance of the 2023 Notes was $124.6 million and was recorded as original debt discount for purposes of accounting for the debt component of the 2023 Notes. This discount is amortized as interest expense using the effective interest method over the term of the 2023 Notes using an effective interest rate of 6.06%. During the fiscal year ended December 30, 2018, we recorded $10.1 million of interest expense related to the amortization of the debt discount. The components of the 2023 Notes were as follows (in thousands): December 30, 2018 Principal amount of 2023 Notes $ 675,000 Unamortized debt discount (114,554 ) Unamortized debt issuance costs (12,370 ) Net carrying amount of 2023 Notes $ 548,076 The estimated fair value of the 2023 Notes was approximately $680.3 million at December 30, 2018 , based on a quoted price in an active market (Level 1). We and WMG entered into 2023 Notes Hedges in connection with the issuance of the 2023 Notes with two counterparties. The 2023 Notes Hedges, which are cash-settled, are generally intended to reduce WMG's exposure to potential cash payments that WMG would be required to make if holders elect to convert the 2023 Notes at a time when our ordinary share price exceeds the conversion price. However, in connection with certain events, including, among others, (i) a merger or other make-whole fundamental change; (ii) certain hedging disruption events, which may include changes in tax laws, an increase in the cost of borrowing our ordinary shares in the market or other material increases in the cost to the option counterparties of hedging the 2023 Note Hedges; (iii) our or WMG's failure to perform certain obligations under the 2023 Notes Indenture or under the 2023 Notes Hedges; (iv) certain defaults on our, WMG's or any our other subsidiary's indebtedness in excess of $25 million ; or (v) if we, WMG or any of our significant subsidiaries become insolvent or otherwise becomes subject to bankruptcy proceedings, the option counterparties have the discretion to terminate the 2023 Notes Hedges, which may reduce the effectiveness of the 2023 Notes Hedges. In addition, the option counterparties have broad discretion to make certain adjustments to the 2023 Notes Hedges and warrant transactions upon the occurrence of certain other events, including, among others, (i) any adjustment to the conversion rate of the 2023 Notes; or (ii) upon the announcement of certain significant corporate events, including events that may give rise to a termination event as described above, such as the announcement of a third-party tender offer. Any such adjustment may also reduce the effectiveness of the 2023 Note Hedges. The aggregate cost of the 2023 Notes Hedges was $141.3 million and is accounted for as a derivative asset in accordance with ASC Topic 815. See Note 6 of the condensed consolidated financial statements for additional information regarding the 2023 Notes Hedges and the 2023 Notes Conversion Derivative. We also entered into warrant transactions in which we sold warrants that are initially exercisable into 20.2 million ordinary shares to the two option counterparties, subject to adjustment upon the occurrence of certain events, for an aggregate of $102.1 million . The strike price of the warrants is $40.86 per share, which was 50% above the last reported sale price of our ordinary shares on June 20, 2018 . The warrants are expected to be net-share settled and exercisable over the 120 trading day period beginning on September 15, 2023. The warrant transactions will have a dilutive effect on our ordinary shares to the extent that the market value per ordinary share during such period exceeds the applicable strike price of the warrants. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to warrant transactions, which may increase our obligations under the warrant transactions. Aside from the initial payment of the $141.3 million premium in the aggregate to the two option counterparties and subject to the right of the option counterparties to terminate the 2023 Notes Hedges in certain circumstances, we do not expect to be required to make any cash payments to the option counterparties under the 2023 Notes Hedges and expect to be entitled to receive from the option counterparties cash, generally equal to the amount by which the market price per ordinary share exceeds the strike price of the convertible note hedging transactions during the relevant valuation period. The strike price under the 2023 Notes Hedges is initially equal to the conversion price of the 2023 Notes. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to the 2023 Note Hedges, which may reduce the effectiveness of the 2023 Note Hedges. Additionally, if the market value per ordinary share exceeds the strike price on any settlement date under the warrant transaction, we will generally be obligated to issue to the option counterparties in the aggregate a number of shares equal in value to one percent of the amount by which the then-current market value of one ordinary share exceeds the then-effective strike price of each warrant, multiplied by the number of ordinary shares into which the 2023 Notes are initially convertible. We will not receive any additional proceeds if warrants are exercised. As described in more detail below, concurrently with the issuance and sale of the 2023 Notes, certain holders of the 2020 Notes exchanged their 2020 Notes for the 2023 Notes. In February 2019, we issued $139.6 million additional aggregate principal amount of the 2023 Notes in exchange for $130.1 million aggregate principal amount of the 2020 Notes and settled a pro rata share of the 2020 Notes Conversion Derivatives, 2020 Notes Hedges and warrants corresponding to the amount of 2020 Notes exchanged pursuant to this exchange. We also entered into additional agreements for 2023 Notes Conversion Derivatives, 2023 Notes Hedges, and warrants. See Note 19 for additional information about this transaction. 2021 Notes On May 20, 2016 , we issued $395 million aggregate principal amount of the 2021 Notes pursuant to an indenture (2021 Notes Indenture), dated as of May 20, 2016 between us and The Bank of New York Mellon Trust Company, N.A., as trustee. The 2021 Notes require interest to be paid at an annual rate of 2.25% semi-annually in arrears on each May 15 and November 15 , and will mature on November 15, 2021 unless earlier converted or repurchased. The 2021 Notes are convertible, subject to certain conditions, solely into cash. The initial conversion rate for the 2021 Notes will be 46.8165 ordinary shares (subject to adjustment as provided in the 2021 Notes Indenture) per $1,000 principal amount of the 2021 Notes (subject to, and in accordance with, the settlement provisions of the 2021 Notes Indenture), which is equal to an initial conversion price of approximately $21.36 per ordinary share. We may not redeem the 2021 Notes prior to the maturity date, and no “sinking fund” is available for the 2021 Notes, which means that we are not required to redeem or retire the 2021 Notes periodically. The holders of the 2021 Notes may convert their 2021 Notes at any time prior to May 15, 2021 solely into cash, in multiples of $1,000 principal amount, upon satisfaction of one or more of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2016 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of 2021 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On or after May 15, 2021 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2021 Notes solely into cash, regardless of the foregoing circumstances. Upon conversion, a holder will receive an amount in cash, per $1,000 principal amount of the 2021 Notes, equal to the settlement amount as calculated under the 2021 Notes Indenture. If we undergo a fundamental change, as defined in the 2021 Notes Indenture, subject to certain conditions, holders of the 2021 Notes will have the option to require us to repurchase for cash all or a portion of their 2021 Notes at a repurchase price equal to 100% of the principal amount of the 2021 Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date, as defined in the 2021 Notes Indenture. In addition, following certain corporate transactions, we, under certain circumstances, will increase the applicable conversion rate for a holder that elects to convert its 2021 Notes in connection with such corporate transaction. The 2021 Notes are senior unsecured obligations that rank: (i) senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the 2021 Notes; (ii) equal in right of payment to any of our unsecured indebtedness that is not so subordinated; (iii) effectively junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness; and (iv) structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries. As a result of the issuance of the 2021 Notes, we recorded deferred financing charges of approximately $7.3 million , which are being amortized over the term of the 2021 Notes using the effective interest method. For the fiscal years ended December 30, 2018, December 31, 2017 , and December 25, 2016, we recorded $1.3 million , $1.1 million , and $0.6 million , respectively, of interest expense related to the amortization of deferred financing costs. In the third fiscal quarter of 2018, the closing price of our ordinary shares was greater than 130% of the 2021 Notes conversion price for 20 or more of the 30 consecutive trading days preceding the quarter-end; and, therefore, the holders of the 2021 Notes had the ability to convert the notes during the succeeding quarterly period. Due to the ability of the holders of the 2021 Notes to convert the notes during this period, the carrying value of the 2021 Notes and the fair value of the 2021 Notes Conversion Derivative were classified as current liabilities, and the fair value of the 2021 Notes Hedges were classified as current assets as of September 30, 2018. There were no conversions during the fourth quarter of 2018. The closing price of our ordinary shares was less than 130% of the 2021 Notes conversion price for more than 20 of the 30 consecutive trading days preceding the calendar fiscal quarter ended December 30, 2018, which resulted in the 2021 Notes no longer being convertible. As such, the 2021 Notes, 2021 Notes Conversion Derivative and 2021 Notes Hedges were classified as long-term as of December 30, 2018. The 2021 Notes Conversion Derivative requires bifurcation from the 2021 Notes in accordance with ASC Topic 815, Derivatives and Hedging , and is accounted for as a derivative liability. See Note 6 for additional information regarding the 2021 Notes Conversion Derivative. The fair value of the 2021 Notes Conversion Derivative at the time of issuance of the 2021 Notes was $117.2 million and was recorded as original debt discount for purposes of accounting for the debt component of the 2021 Notes. This discount is amortized as interest expense using the effective interest method over the term of the 2021 Notes. For the fiscal years ended December 30, 2018, December 31, 2017 , and December 25, 2016, we recorded $20.0 million , $18.1 million , and $ 9.8 million respectively, of interest expense related to the amortization of the debt discount based upon an effective rate of 9.72% . The components of the 2021 Notes were as follows (in thousands): December 30, 2018 December 31, 2017 Principal amount of 2021 Notes $ 395,000 $ 395,000 Unamortized debt discount (69,382 ) (89,332 ) Unamortized debt issuance costs (4,332 ) (5,617 ) Net carrying amount of 2021 Notes $ 321,286 $ 300,051 The estimated fair value of the 2021 Notes was approximately $533.4 million at December 30, 2018 , based on a quoted price in an active market (Level 1). We entered into 2021 Notes Hedges in connection with the issuance of the 2021 Notes with two counterparties. The 2021 Notes Hedges, which are cash-settled, are generally intended to reduce our exposure to potential cash payments that we would be required to make if holders elect to convert the 2021 Notes at a time when our ordinary share price exceeds the conversion price. However, in connection with certain events, including, among others, (i) a merger or other make-whole fundamental change (as defined in the 2021 Notes Indenture); (ii) certain hedging disruption events, which may include changes in tax laws, an increase in the cost of borrowing our ordinary shares in the market or other material increases in the cost to the option counterparties of hedging the 2021 Note Hedges; (iii) our failure to perform certain obligations under the 2021 Notes Indenture or under the 2021 Notes Hedges; (iv) certain payment defaults on our existing indebtedness in excess of $25 million; or (v) if we or any of our significant subsidiaries become insolvent or otherwise becomes subject to bankruptcy proceedings, the option counterparties have the discretion to terminate the 2021 Notes Hedges, which may reduce the effectiveness of the 2021 Notes Hedges. In addition, the option counterparties have broad discretion to make certain adjustments to the 2021 Notes Hedges and warrant transactions upon the occurrence of certain other events, including, among others, (i) any adjustment to the conversion rate of the 2021 Notes; or (ii) upon the announcement of certain significant corporate events, including events that may give rise to a termination event as described above, such as the announcement of a third-party tender offer. Any such adjustment may also reduce the effectiveness of the 2021 Note Hedges. The aggregate cost of the 2021 Notes Hedges was $99.8 million and is accounted for as a derivative asset in accordance with ASC Topic 815. See Note 6 of the consolidated financial statements for additional information regarding the 2021 Notes Hedges and the 2021 Notes Conversion Derivative. We also entered into warrant transactions in which we sold warrants for an aggregate of 18.5 million ordinary shares to the two option counterparties, subject to adjustment, for an aggregate of $54.6 million . The strike price of the warrants is $30.00 per share, which was 69% above the last reported sale price of our ordinary shares on May 12, 2016 . The warrants are expected to be net-share settled and exercisable over the 100 trading day period beginning on February 15, 2022. The warrant transactions will have a dilutive effect on our ordinary shares to the extent that the market value per ordinary share during such period exceeds the applicable strike price of the warrants. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to warrant transactions, which may increase our obligations under the warrant transactions. Aside from the initial payment of the $99.8 million premium in the aggregate to the two option counterparties and subject to the right of the option counterparties to terminate the 2021 Notes Hedges in certain circumstances, we do not expect to be required to make any cash payments to the option counterparties under the 2021 Notes Hedges and expect to be entitled to receive from the option counterparties cash, generally equal to the amount by which the market price per ordinary share exceeds the strike price of the convertible note hedging transactions during the relevant valuation period. The strike price under the 2021 Notes Hedges is initially equal to the conversion price of the 2021 Notes. However, in connection with certain events, these option counterparties have the discretion to make certain adjustments to the 2021 Note Hedges, which may reduce the effectiveness of the 2021 Note Hedges. Additionally, if the market value per ordinary share exceeds the strike price on any settlement date under the warrant transaction, we will generally be obligated to issue to the option counterparties in the aggregate a number of shares equal in value to one percent of the amount by which the then-current market value of one ordinary share exceeds the then-effective strike price of each warrant, multiplied by the number of ordinary shares into which the 2021 Notes are initially convertible. We will not receive any additional proceeds if warrants are exercised. As described in more detail below, concurrently with the issuance and sale of the 2021 Notes, certain holders of the 2017 Notes and the 2020 Notes exchanged their 2017 Notes or 2020 Notes for the 2021 Notes. 2020 Notes On February 13, 2015 , WMG issued $632.5 million aggregate principal amount of the 2020 Notes pursuant to an indenture (2020 Notes Indenture), dated as of February 13, 2015 between WMG and The Bank of New York Mellon Trust Company, N.A., as trustee. The 2020 Notes require interest to be paid semi-annually on each February 15 and August 15 at an annual rate of 2.00% , and mature on February 15, 2020 unless earlier converted or repurchased. The 2020 Notes were initially issued whereby they were convertible at the option of the holder, during certain periods and subject to certain conditions described below, solely into cash at an initial conversion rate of 32.3939 shares of WMG common stock per $1,000 principal amount of the 2020 Notes, subject to adjustment upon the occurrence of certain events, which represented an initial conversion price of approximately $30.87 per share of WMG common stock. On November 24, 2015, Wright Medical Group N.V. executed a supplemental indenture, fully and unconditionally guaranteeing, on a senior unsecured basis, WMG’s obligations relating to the 2020 Notes, changing the underlying reference securities from WMG common stock to Wright Medical Group N.V. ordinary shares and making a corresponding adjustment to the conversion price. From and after the effective time of the Wright/Tornier merger, (i) all calculations and other determinations with respect to the 2020 Notes previously based on references to WMG common stock are calculated or determined by reference to our ordinary shares, and (ii) the conversion rate (as defined in the 2020 Notes Indenture) for the 2020 Notes was adjusted to a conversion rate of 33.39487 ordinary shares (subject to adjustment as provided in the 2020 Notes Indenture) per $1,000 principal amount of the 2020 Notes, which represents a conversion price of approximately $29.94 per ordinary share (subject to, and in accordance with, the settlement provisions of the 2020 Notes Indenture). The 2020 Notes may not be redeemed by WMG prior to the maturity date, and no “sinking fund” is available for the 2020 Notes, which means that WMG is not required to redeem or retire the 2020 Notes periodically. The holders of the 2020 Notes may convert their notes at any time prior to August 15, 2019 solely into cash, in multiples of $1,000 principal amount, upon satisfaction of one or more of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2015 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of 2020 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. The Wright/Tornier merger did not result in a conversion right for holders of the 2020 Notes. On or after August 15, 2019 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2020 Notes solely into cash, regardless of the foregoing circumstances. Upon conversion, a holder will receive an amount in cash, per $1,000 principal amount of the 2020 Notes, equal to the settlement amount as calculated under the 2020 Notes Indenture. If WMG undergoes a fundamental change, as defined in the 2020 Notes Indenture, subject to certain conditions, holders of the 2020 Notes will have the option to require WMG to repurchase for cash all or a portion of their notes at a purchase price equal to 100% of the principal amount of the 2020 Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date, as defined in the 2020 Notes Indenture. In addition, following certain corporate transactions, WMG, under certain circumstances, will increase the applicable conversion rate for a holder that elects to convert its 2020 Notes in connection with such corporate transaction. The 2020 Notes are senior unsecured obligations that rank: (i) senior in right of payment to any of WMG's indebtedness that is expressly subordinated in right of payment to the 2020 Notes; (ii) equal in right of payment to any of WMG's unsecured indebtedness that is not so subordinated; (iii) effectively junior in right of payment to any secured indebtedness to the extent of the value of the assets securing such indebtedness; and (iv) structurally junior to all indebtedness and other liabilities (including trade payables) of WMG's subsidiaries. In conjunction with the issuance of the 2020 Notes, we recorded deferred financing charges of approximately $18.1 million . Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes and the fair value of the 2020 Notes Conversion Derivatives were classified as current liabilities and the fair value of the 2020 Notes Hedges was classified as current assets as of December 30, 2018. The respective balances were all classified as long-term as of December 31, 2017. The 2020 Notes Conversion Derivative requires bifurcation from the 2020 Notes in accordance with ASC Topic 815, Derivatives and Hedging, and is accounted for as a derivative liability. See Note 6 of the consolidated financial statements for additional information regarding the 2020 Notes Conversion Derivative. The fair value of the 2020 Notes Conversion Derivative at the time of issuance of the 2020 Notes was $149.8 million and was recorded as original debt discount for purposes of accounting for the debt component of the 2020 Notes. Concurrently with the issuance and sale of the 2021 Notes, certain holders of the 2020 Notes exchanged approximately $45.0 million aggregate principal amount of their 2020 Notes for the 2021 Notes. For each $1,000 principal amount of 2020 Notes validly submitted for exchange, we delivered $990.00 principal amount of the 2021 Notes (subject to rounding down to the nearest $1,000 principal amount of the 2021 Notes, the difference being referred as the rounded amount) to the investor plus an amount of cash equal to the unpaid interest on the 2020 Notes and the rounded amount. As a result of this note exchange and retirement of $45.0 million aggregate principal amount of the 2020 Notes, we recognized approximately $9.3 million for the write-off of related pro rata unamortized deferred financing fees and debt discount within “Other expense (income), net” in our consolidated statements of operations during the fiscal year ended December 31, 2017 . Concurrently with the issuance and sale of the 2023 Notes, certain holders of the 2020 Notes exchanged approximately $400.9 million aggregate principal amount of their 2020 Notes for the 2023 Notes. For each $1,000 principal amount of 2020 Notes validly submitted for exchange, we delivered $1,138.70 principal amount of the 2023 Notes (subject to rounding down to the nearest $1,000 principal amount of the 2023 Notes for each exchanging investor, the difference being referred as the rounded amount) to the investor. As a result of this note exchange and retirement of $400.9 million aggregate principal amount of the 2020 Notes, we recognized approximately $39.9 million for the write-off of related unamortized deferred financing fees and debt discount within “Other (income) expense, net” in our consolidated statements of operations during the fiscal year ended December 30, 2018. The remaining deferred financing charges and discount on the 2020 Notes are being amortized over the remaining term of the 2020 Notes using the effective interest method. For the fiscal years ended December 30, 2018 , December 31, 2017 and December 25, 2016, we recorded $19.1 million , $27.3 million and $25.9 million , respectively, of interest expense related to the amortization of the debt discount based upon an effective rate of 8.54% . For the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016, we recorded $2.3 million , $3.3 million and $3.1 million , respectively, of interest expense related to the amortization of deferred financing costs. The components of the 2020 Notes were as follows (in thousands): December 30, 2018 December 31, 2017 Principal amount of 2020 Notes $ 186,589 $ 587,500 Unamortized debt discount (11,642 ) (66,418 ) Unamortized debt issuance costs (1,414 ) (8,068 ) Net carrying amount of 2020 Notes $ 173,533 $ 513,014 The estimated fair value of the 2020 Notes was approximately $196.9 million at December 30, 2018 , based on a quoted price in an active market (Level 1). WMG entered into the 2020 Notes Hedges in connection with the issuance of the 2020 Notes with three option counterparties. See Note 6 of the consolidated financial statements for additional information on the 2020 Notes Hedges. The 2020 Notes Hedges, which are cash-settled, a

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Notes)	12 Months Ended
	Dec. 30, 2018
Accumulated Other Comprehensive Income [Abstract]
Comprehensive Income (Loss), Note	Accumulated Other Comprehensive Income (AOCI) Other comprehensive income (OCI) includes certain gains and losses that under US GAAP are included in comprehensive income but are excluded from net loss as these amounts are initially recorded as an adjustment to shareholders’ equity. Amounts in OCI may be reclassified to net loss upon the occurrence of certain events. Our 2016, 2017, and 2018 OCI is comprised of foreign currency translation adjustments. Changes in AOCI for the fiscal years ended December 25, 2016 , December 31, 2017 , and December 30, 2018 were as follows (in thousands): Currency translation adjustment Balance December 27, 2015 $ (10,484 ) Other comprehensive loss (8,977 ) Balance December 25, 2016 $ (19,461 ) Other comprehensive income 41,751 Balance December 31, 2017 $ 22,290 Other comprehensive loss (30,373 ) Balance December 30, 2018 $ (8,083 )

Income Taxes

Income Taxes	12 Months Ended
	Dec. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of our loss from continuing operations before income taxes are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 U.S. $ (144,987 ) $ (56,808 ) $ (140,190 ) Foreign (24,853 ) (43,097 ) (38,150 ) Loss from continuing operations before income taxes $ (169,840 ) $ (99,905 ) $ (178,340 ) The components of our benefit for income taxes are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Current (benefit) provision: U.S.: Federal $ 449 $ (23,781 ) $ (1,971 ) State 251 390 (281 ) Foreign 3,307 2,214 3,860 Total current (benefit) provision 4,007 (21,177 ) 1,608 Deferred (benefit) provision: U.S.: Federal (2,841 ) (5,098 ) 1,244 State (663 ) (93 ) 142 Foreign (1,039 ) (8,600 ) (16,400 ) Total deferred benefit (4,543 ) (13,791 ) (15,014 ) Total benefit for income taxes $ (536 ) $ (34,968 ) $ (13,406 ) A reconciliation of the statutory U.S. federal income tax rate to our effective income tax rate for continuing operations is as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Income tax benefit at statutory rate 21.0 % 35.0 % 35.0 % State income taxes 3.8 % 1.5 % 2.9 % Change in valuation allowance (22.9 )% (3.5 )% (32.6 )% CVR fair market value adjustment — % (1.9 )% (1.7 )% Foreign income tax rate differential (0.6 )% (6.1 )% 3.3 % Changes in tax reserves 0.4 % 2.9 % 0.8 % Effects of U.S. tax reform — % 6.5 % — % Foreign rate changes — % 1.7 % — % Other, net (1.4 )% (1.1 )% (0.2 )% Total 0.3 % 35.0 % 7.5 % The significant components of our deferred income taxes as of December 30, 2018 and December 31, 2017 are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 Deferred tax assets: Net operating loss carryforwards $ 330,589 $ 283,708 General business credit carryforwards 14,598 12,993 Reserves and allowances 56,675 90,246 Deferred interest 27,322 — Share-based compensation expense 14,934 13,679 Convertible debt notes and conversion options 38,368 10,747 Other 3,616 1,642 Valuation allowance (400,171 ) (366,825 ) Total deferred tax assets 85,931 46,190 Deferred tax liabilities: Depreciation 5,095 6,383 Intangible assets 58,221 42,862 Convertible notes bond hedges 34,653 11,668 Other 166 120 Total deferred tax liabilities 98,135 61,033 Net deferred tax liabilities $ (12,204 ) $ (14,843 ) The 2017 Tax Act was enacted on December 22, 2017. We recognized the income tax effects of the 2017 Tax Act in our 2017 financial statements in accordance with Staff Accounting Bulletin No. 118, which provides SEC staff guidance for the application of ASC Topic 740, Income Taxes, in the reporting period in which the 2017 Tax Act was signed into law. As such, our 2017 financial results included an approximate $6.6 million benefit resulting from the revaluation of our net deferred tax liabilities and reduction of our valuation allowance due to the change in the net operating loss carryforward period. Based on updated notices and regulations issued by the IRS, U.S. Treasury, and other standard-setting bodies in 2018, we have finalized our income tax effects for the provisions of the 2017 Tax Act in the fourth-quarter 2018 with no significant impact. In addition, the 2017 Tax Act imposed a tax on global intangible low-taxed income (GILTI) earned by U.S. controlled foreign subsidiaries. In accordance with FASB Staff Q&A, Topic 740, No. 5, we have elected to account for GILTI as a period expense in the year it is incurred. While we have included a provisional amount relating to GILTI in our financial statements, there is no net income tax impact due to the valuation allowance provided on our U.S. deferred tax assets. At December 30, 2018 , we had net operating loss carryforwards for U.S. federal income tax purposes of approximately $1.1 billion , $150.0 million of which do not expire and $965.0 million which are subject to expiration. Of the U.S. net operating loss carryforwards subject to expiration, approximately $15.0 million will expire over the next 5 years and the remaining between 2024 and 2037, with the majority expiring after 2033. State net operating loss carryforwards at December 30, 2018 totaled approximately $1.2 billion , $25.0 million of which do not expire and $1.16 billion which begin to expire in 2019 and extend through 2038. Additionally, we had general business credit carryforwards of approximately $15.0 million , which begin to expire in 2019 and extend through 2038. At December 30, 2018 , we had foreign net operating loss carryforwards of approximately $163.0 million , $77.0 million of which do not expire and $86.0 million which begin to expire in 2019 and extend through 2027. At December 30, 2018 and December 31, 2017 , we had a valuation allowance of $400.2 million and $366.8 million , respectively, related to certain U.S. and foreign deferred tax assets. We realized a net increase in the valuation allowance of $33.0 million during the fiscal year ended December 30, 2018 . The net increase was primarily due to the valuation allowance on projected U.S. current year taxable losses and a change in judgment regarding our ability to recognize certain foreign deferred tax assets, partially offset by a change in the realizability of certain U.S. deferred tax assets as a result of the Cartiva acquisition, for which approximately $3.6 million was recognized as an income tax benefit. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities (including the impact of available carryback and carryforward periods), projected future taxable income, and tax planning strategies in making this assessment. Based upon the levels of historical taxable income, projections of future taxable income and the reversal of deferred tax liabilities over the periods in which the deferred tax assets are deductible, management believes it is more likely than not that we will realize the benefits of these deductible differences, net of the existing valuation allowance. It is our current practice and intention to reinvest the earnings of our subsidiaries in those operations. Therefore, we do not provide for deferred taxes on the excess of the financial reporting over the tax basis in our investments in subsidiaries that are essentially permanent in duration. We would recognize a deferred income tax liability if we were to determine that such earnings are no longer indefinitely reinvested. Due to the number of tax jurisdictions involved, the complexity of our legal entity structure, and the complexity of the tax laws in the relevant jurisdictions, we believe it is not practicable to estimate the amount of additional taxes which may be payable upon distribution of these earnings, however it is not expected to be significant. Further, the 2017 Tax Act imposed a mandatory transition tax on accumulated foreign earnings of our U.S. controlled foreign subsidiaries and eliminated U.S. income taxes on distributions from U.S. controlled foreign subsidiaries. As of December 30, 2018 , our unrecognized tax benefits totaled approximately $4.6 million . The total amount of net unrecognized tax benefits that, if recognized, would affect the tax rate was approximately $1.0 million at December 30, 2018 . While we are currently not under audit in significant tax jurisdictions, it is reasonably possible that our unrecognized tax benefits could change in the next twelve months as a result of tax periods still open for examination and expirations of the statutes of limitations. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 Balance at beginning of fiscal year $ 6,025 $ 8,095 Additions from acquisitions 109 — Additions for tax positions related to current year 385 215 Additions for tax positions of prior years 718 20 Reductions for tax positions of prior years (490 ) (3,174 ) Settlements (1,983 ) — Foreign currency translation (154 ) 869 Balance at end of fiscal year $ 4,610 $ 6,025 We accrue interest required to be paid by the tax law for the underpayment of taxes on the difference between the amount claimed or expected to be claimed on the tax return and the tax benefit recognized in the financial statements. Management has made the policy election to record this interest as interest expense and penalties, that if incurred, would be recognized as penalty expense within “Other expense (income)” on our consolidated statements of operations. As of December 30, 2018 , accrued interest and penalties related to our unrecognized tax benefits totaled approximately $0.2 million . We file numerous consolidated and separate company income tax returns in the United States and in many foreign jurisdictions. With few exceptions, we are subject to U.S. federal, state, and local income tax examinations for years 2015 through 2017. We are no longer subject to foreign income tax examinations by tax authorities in significant jurisdictions for years before 2014. However, U.S. and foreign tax authorities have the ability to review years prior to these to the extent that we utilize tax attributes carried forward from those prior years.

Other Balance Sheet Information

Other Balance Sheet Information	12 Months Ended
	Dec. 30, 2018
Other Long-Term Liabilities [Abstract]
Earnings Per Share [Text Block]	Capital Stock and Earnings Per Share We are authorized to issue up to 320 million ordinary shares, each share with a par value of three Euro cents ( €0.03 ). We had 125.6 million and 105.8 million ordinary shares issued and outstanding as of December 30, 2018 and December 31, 2017 , respectively. On August 27, 2018, we entered into an underwriting agreement with J.P. Morgan, relating to the registered public offering of 18.2 million ordinary shares, at an initial price to the public of $24.60 per share, for a total price of $448.9 million . The net proceeds to us were $423.0 million , after deducting underwriting discounts and commissions of $25.4 million and offering costs of $0.5 million . The offering closed on August 30, 2018. The proceeds were used to fund the purchase price of the Cartiva acquisition which closed on October 10, 2018, as well as costs and expenses related thereto. See Note 3 for additional details related to the Cartiva acquisition. FASB ASC Topic 260, Earnings Per Share, requires the presentation of basic and diluted earnings per share. Basic earnings per share is calculated based on the weighted-average number of ordinary shares outstanding during the period. Diluted earnings per share is calculated to include any dilutive effect of our ordinary share equivalents. For the fiscal years ended December 30, 2018 and December 31, 2017 , our ordinary share equivalents consisted of stock options, restricted stock units, performance share units, and warrants. For the fiscal year ended December 25, 2016 , our ordinary share equivalents consisted of stock options, restricted stock units, and warrants. The dilutive effect of the stock options, restricted stock units, performance share units, and warrants is calculated using the treasury-stock method. We had outstanding options to purchase 9.9 million ordinary shares, 1.3 million restricted stock units, and 0.2 million performance share units, assuming target performance, at December 30, 2018 ; outstanding options to purchase 10.0 million ordinary shares, 1.3 million restricted stock units, and $0.1 million performance share units, assuming target performance, at December 31, 2017 ; and outstanding options to purchase 10.4 million ordinary shares and 1.3 million restricted stock units at December 25, 2016 . We had outstanding net-share settled warrants on the 2020 Notes of 6.2 million ordinary shares at December 30, 2018 and 19.6 million ordinary shares at December 31, 2017 and December 25, 2016 . We also had net-share settled warrants on the 2021 Notes of 18.5 million ordinary shares at December 30, 2018 and December 31, 2017 . Finally, we had net-share settled warrants on the 2023 Notes of 20.2 million ordinary shares at December 30, 2018 . None of the options, restricted stock units, performance share units, or warrants were included in the calculation of diluted net loss from continuing operations per share, diluted net loss from discontinued operations per shares, and diluted net loss per share for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , because we recorded a net loss from continuing operations for all periods. Including these instruments would be anti-dilutive as the net loss from continuing operations is the control number in determining whether those potential common shares are dilutive or anti-dilutive. The weighted-average number of ordinary shares outstanding for basic and diluted loss per share purposes is as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Weighted-average number of ordinary shares outstanding — basic and diluted 112,592 104,531 102,968
Supplemental Balance Sheet Disclosures [Text Block]	Other Balance Sheet Information Other long-term liabilities consist of the following (in thousands): December 30, 2018 December 31, 2017 Product liability reserves ( Note 16 ) $ 30,755 $ 60,711 Notes Conversion Derivatives ( Note 6 ) 304,372 170,280 Contingent consideration ( Note 6 ) 15,821 18,301 Other 17,281 23,453 $ 368,229 $ 272,745 Accrued expenses and other current liabilities consist of the following (in thousands): December 30, 2018 December 31, 2017 Employee bonuses $ 28,953 $ 12,803 Other employee benefits 22,841 22,401 Royalties 12,330 12,563 Taxes other than income 7,897 8,933 Notes Conversion Derivatives ( Note 6 ) 17,386 — Commissions 19,356 19,330 Professional and legal fees 10,848 12,388 Contingent consideration ( Note 6 ) 3,427 1,168 Product liability and other legal accruals ( Note 16 ) 66,918 151,027 CVRs ( Note 6 ) 420 42,044 Other 26,705 31,901 $ 217,081 $ 314,558

Earnings per share (Notes)

Earnings per share (Notes)	12 Months Ended
	Dec. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Capital Stock and Earnings Per Share We are authorized to issue up to 320 million ordinary shares, each share with a par value of three Euro cents ( €0.03 ). We had 125.6 million and 105.8 million ordinary shares issued and outstanding as of December 30, 2018 and December 31, 2017 , respectively. On August 27, 2018, we entered into an underwriting agreement with J.P. Morgan, relating to the registered public offering of 18.2 million ordinary shares, at an initial price to the public of $24.60 per share, for a total price of $448.9 million . The net proceeds to us were $423.0 million , after deducting underwriting discounts and commissions of $25.4 million and offering costs of $0.5 million . The offering closed on August 30, 2018. The proceeds were used to fund the purchase price of the Cartiva acquisition which closed on October 10, 2018, as well as costs and expenses related thereto. See Note 3 for additional details related to the Cartiva acquisition. FASB ASC Topic 260, Earnings Per Share, requires the presentation of basic and diluted earnings per share. Basic earnings per share is calculated based on the weighted-average number of ordinary shares outstanding during the period. Diluted earnings per share is calculated to include any dilutive effect of our ordinary share equivalents. For the fiscal years ended December 30, 2018 and December 31, 2017 , our ordinary share equivalents consisted of stock options, restricted stock units, performance share units, and warrants. For the fiscal year ended December 25, 2016 , our ordinary share equivalents consisted of stock options, restricted stock units, and warrants. The dilutive effect of the stock options, restricted stock units, performance share units, and warrants is calculated using the treasury-stock method. We had outstanding options to purchase 9.9 million ordinary shares, 1.3 million restricted stock units, and 0.2 million performance share units, assuming target performance, at December 30, 2018 ; outstanding options to purchase 10.0 million ordinary shares, 1.3 million restricted stock units, and $0.1 million performance share units, assuming target performance, at December 31, 2017 ; and outstanding options to purchase 10.4 million ordinary shares and 1.3 million restricted stock units at December 25, 2016 . We had outstanding net-share settled warrants on the 2020 Notes of 6.2 million ordinary shares at December 30, 2018 and 19.6 million ordinary shares at December 31, 2017 and December 25, 2016 . We also had net-share settled warrants on the 2021 Notes of 18.5 million ordinary shares at December 30, 2018 and December 31, 2017 . Finally, we had net-share settled warrants on the 2023 Notes of 20.2 million ordinary shares at December 30, 2018 . None of the options, restricted stock units, performance share units, or warrants were included in the calculation of diluted net loss from continuing operations per share, diluted net loss from discontinued operations per shares, and diluted net loss per share for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , because we recorded a net loss from continuing operations for all periods. Including these instruments would be anti-dilutive as the net loss from continuing operations is the control number in determining whether those potential common shares are dilutive or anti-dilutive. The weighted-average number of ordinary shares outstanding for basic and diluted loss per share purposes is as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Weighted-average number of ordinary shares outstanding — basic and diluted 112,592 104,531 102,968

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Share-Based Compensation We currently have two share-based compensation plans under which share-based awards may be granted - the Wright Medical Group N.V. 2017 Equity and Incentive Plan and the Wright Medical Group N.V. Amended and Restated Employee Stock Purchase Plan, which are described below. In addition, we have the Wright Medical Group N.V. Amended and Restated 2010 Incentive Plan and several legacy Wright and legacy Tornier share-based compensation plans and non-plan agreements under which stock options and restricted stock units are outstanding, but no future share-based awards may be granted. Amounts recognized in the consolidated financial statements with respect to share-based compensation are as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Total cost of share-based arrangements $ 26,039 $ 19,485 $ 14,406 Amounts capitalized into inventory (507 ) (669 ) (416 ) Amortization of capitalized amounts 588 577 426 Impact to net loss $ 26,120 $ 19,393 $ 14,416 Impact to basic and diluted loss per share $ 0.23 $ 0.19 $ 0.14 Weighted-average number of shares outstanding - basic and diluted 112,592 104,531 102,968 The compensation costs related to share-based awards were as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Stock options $ 11,177 $ 8,988 $ 5,844 Restricted stock units 11,514 9,373 8,416 Performance share units 2,538 441 — Employee stock purchase plan 810 683 146 Total compensation cost for share-based awards $ 26,039 $ 19,485 $ 14,406 As of December 30, 2018 , we had $48.0 million of total unrecognized share-based compensation cost related to unvested share-based compensation arrangements. This cost is expected to be recognized over a weighted-average period of 2.57 years. Equity Incentive Plans and Non-Plan Inducement Agreements The Wright Medical Group N.V. 2017 Equity and Incentive Plan (the 2017 Plan) was approved by our shareholders on June 23, 2017. The 2017 Plan authorizes us to grant a wide variety of share-based and cash-based awards, including incentive and non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units, performance awards, cash-based awards, and other share-based awards. To date, only stock options, restricted stock units (RSUs), and performance share units (PSUs) have been granted. The options and RSUs granted to our employees generally have graded vesting periods of 4 years. The options granted to our non-executive directors have graded vesting period of 2 years and the RSUs granted to our non-executive directors cliff vest on the one -year anniversary of the date of grant. All options are granted with exercise prices equal to the closing price of our ordinary shares on the date of grant, as reported by the Nasdaq Global Select Market, and expire 10 years after the grant date. The PSUs granted to our executive officers cliff vest after a three -year performance period only if certain minimum pre-established performance criteria are achieved and the number shares issued upon vesting depends upon the level of achievement of the performance criteria, with a cap of 200% of target levels. The PSUs granted during the fiscal year ended December 30, 2018 were granted in the third quarter of 2018 and have a performance period from July 2, 2018 to June 25, 2021 . The PSUs granted during the fiscal year ended December 31, 2017 were granted in the third quarter of 2017 and have a performance period from June 26, 2017 to June 28, 2020 . The 2017 Plan reserves for issuance a number of ordinary shares equal to the sum of (i) 5,000,000 shares; (ii) 1,329,648 shares, which was the number of shares available for grant under the Wright Medical Group N.V. Amended and Restated 2010 Incentive Plan (the 2010 Plan) as of June 23, 2017, the date of shareholder approval of the 2017 Plan, but not subject to outstanding awards; and (iii) up to 6,405,992 shares subject to awards outstanding under the 2010 Plan as of June 23, 2017 that are subsequently forfeited or cancelled or expire or otherwise terminate without the issuance of such shares. As of December 30, 2018 , 2,297,162 ordinary shares remained available for future grant of equity awards under the 2017 Plan, assuming maximum PSU payouts. As of December 30, 2018 , there were 11,451,090 ordinary shares covering awards outstanding under all of our equity incentive plans, including the 2017 Plan, the 2010 Plan and legacy Wright and legacy Tornier plans and non-plan agreements, assuming target PSU payouts. The legacy Wright and legacy Tornier plans and non-plan agreements include the Wright Medical Group, Inc. 2009 Equity Incentive Plan, as amended and restated (the Legacy Wright 2009 Plan), the Wright Medical Group, Inc. 1999 Equity Incentive Plan, as amended and restated, the Tornier N.V. Stock Option Plan, as amended and restated, and three legacy Wright non-plan inducement option agreements. All of these plans and non-plan agreements were terminated with respect to future awards, and thus, no future share-based awards may be granted under any of these legacy plans and agreements. All of the options issued under the legacy Wright plans and non-plan agreements expire after 10 years from the date of grant. All outstanding awards under the legacy Wright plans and non-plan agreements automatically vested on October 1, 2015 as a result of the Wright/Tornier merger; therefore, there are no restricted stock awards or RSUs outstanding at December 30, 2018 under these plans. However, there were 2,547,656 stock options outstanding as of December 30, 2018 under the legacy Wright plans and non-plan agreements. Stock options We estimate the fair value of stock options using the Black-Scholes valuation model. The Black-Scholes option-pricing model requires the input of estimates, including the expected life of stock options, expected stock price volatility, the risk-free interest rate and the expected dividend yield. The expected life of options was estimated based on historical option exercise and employee termination data. The expected stock price volatility assumption was estimated based upon historical volatility of our ordinary shares for both legacy Wright and legacy Tornier prior to October 1, 2015 and for the combined company after the Wright/Tornier merger. The risk-free interest rate was determined using U.S. Treasury rates where the term is consistent with the expected life of the stock options. Expected dividend yield is not considered as we have never paid dividends and have no plans of doing so in the future. We are required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. We use historical data to estimate pre-vesting forfeitures and record share-based compensation expense only for those awards that are expected to vest. The fair value of stock options is amortized on a straight-line basis over the respective requisite service period, which is generally the vesting period. The weighted-average grant date fair value of stock options granted to employees in 2018 , 2017 , and 2016 was $9.32 per share, $9.80 per share, and $7.36 per share, respectively. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option valuation model using the following assumptions: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Risk-free interest rate 2.6% - 2.9% 1.9% - 2.0% 1.1% - 1.4% Expected option life 7 years 6 years 6 years Expected price volatility 32% 33% 34% During 2018 , 2017 , and 2016 , we did not grant any stock options to non-employees (other than our non-executive directors who received such grants in consideration of their director service). A summary of our stock option activity during 2018 is as follows: Shares (000’s) Weighted-average exercise price Weighted-average remaining contractual life Aggregate intrinsic value* ($000’s) Outstanding at December 31, 2017 9,114 $ 22.73 Granted 1,464 24.14 Exercised (750) 21.18 Forfeited or expired (625) 25.51 Outstanding at December 30, 2018 9,203 $ 22.89 6.52 $ 36,809 Exercisable at December 30, 2018 6,086 $ 22.30 5.46 $ 28,127 ________________________________ * The aggregate intrinsic value is calculated as the difference between the market value of our ordinary shares as of December 30, 2018 and the respective exercise prices of the options. The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018 , the last trading day prior to December 30, 2018 , as reported by the Nasdaq Global Select Market. The total intrinsic value of options exercised during 2018 , 2017 , and 2016 was $4.9 million , $9.1 million , and $2.1 million , respectively. A summary of our stock options outstanding and exercisable at December 30, 2018 is as follows (shares in thousands): Options outstanding Options exercisable Range of exercise prices Number outstanding Weighted-average remaining Weighted-average exercise Number exercisable Weighted-average exercise $2.00 — $20.00 1,078 4.02 $ 17.66 976 $ 17.48 $20.01 — $21.00 2,276 6.32 20.64 1,835 20.64 $21.01 — $25.00 3,753 7.16 22.85 1,945 22.21 $25.01 — $32.00 2,096 6.87 28.10 1,330 28.27 9,203 6.52 $ 22.89 6,086 $ 22.30 Restricted stock units We calculate the grant date fair value of RSUs using the closing sale price of our ordinary shares on the grant date, as reported by the Nasdaq Global Select Market. We are required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. We use historical data to estimate pre-vesting forfeitures and record share-based compensation expense only for those awards that are expected to vest. The fair value of the unvested restricted stock units is recognized on a straight-line basis over the respective requisite service period, which is generally the vesting period. During 2018 , 2017 , and 2016 , we granted 0.6 million , 0.5 million , 0.7 million RSUs to employees with weighted-average grant-date fair values of $24.05 , $27.83 , and $21.17 per share, respectively. During 2018 , 2017 , and 2016 , we did not grant any RSUs to non-employees (other than our non-executive directors who received such grants in consideration of their director service). A summary of our RSU activity during 2018 is as follows: Shares (000’s) Weighted-average grant-date fair value Aggregate intrinsic value* ($000’s) Unvested at December 31, 2017 1,280 $ 23.45 Granted 607 24.05 Vested (460 ) 22.89 Forfeited (105 ) 23.63 Unvested at December 30, 2018 1,322 $ 23.90 $ 35,052 ___________________ * The aggregate intrinsic value is calculated as the market value of our ordinary shares as of December 30, 2018 . The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018 , the last trading day prior to December 30, 2018 , as reported by the Nasdaq Global Select Market. The total fair value of shares underlying RSUs vested during 2018 , 2017 , and 2016 was $12.2 million , $9.0 million , and $7.0 million , respectively. Performance share units We calculate the grant date fair value of PSUs as the closing sale price of our ordinary shares on the grant date, as reported by the Nasdaq Global Select Market. Share-based compensation expense associated with outstanding PSUs is measured using the grant date fair value and is based on the estimated achievement of the established performance criteria at the end of each reporting period until the performance period ends, recognized on a straight-line basis over the performance period. Share-based compensation expense is only recognized for PSUs that we expect to vest, which we estimate based upon an assessment of the probability that the performance criteria will be achieved. The PSUs granted during the fiscal years ended December 30, 2018 and December 31, 2017 have a three-year performance-based metric measured over a performance period from July 2, 2018 to June 25, 2021 and June 26, 2017 to June 28, 2020 , respectively. Share-based compensation expense associated with outstanding PSUs is updated for actual forfeitures. During 2018 and 2017 , we granted 0.1 million and 0.1 million PSUs (based on an assumed target level of performance) to employees with a weighted-average grant-date fair value of $24.49 and $27.86 per share, respectively. During 2018 and 2017 , we did not grant any PSUs to non-employees. A summary of our PSU activity during 2018 is as follows: Shares (000’s) Weighted-average grant-date fair value Aggregate intrinsic value* ($000’s) Unvested at December 31, 2017 108 $ 27.86 Granted 129 24.49 Vested — — Forfeited (4 ) 27.86 Unvested at December 30, 2018 233 $ 26.00 $ 6,176 ___________________ * The aggregate intrinsic value is calculated as the market value of our ordinary shares as of December 30, 2018 . The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018 , the last trading day prior to December 30, 2018 , as reported by the Nasdaq Global Select Market. Non-plan inducement stock options On occasion, legacy Wright granted stock options under a non-plan inducement stock option agreement, in order to induce a candidate to commence employment with legacy Wright as a member of the executive management team. These options, which are fully vested, vested over a service period ranging from 3 to 4 years. All of the options granted under these non-plan agreements will expire 10 years from the date of grant. A summary of our non-plan inducement stock option activity during 2018 is as follows: Shares (000’s) Weighted-average exercise price Weighted-average remaining contractual life Aggregate intrinsic value* ($000’s) Outstanding at December 31, 2017 875 $ 16.50 Granted — — Exercised (182 ) 19.71 Forfeited or expired — — Outstanding at December 30, 2018 693 $ 15.66 2.74 $ 7,522 Exercisable at December 30, 2018 693 $ 15.66 2.74 $ 7,522 ________________________________ * The aggregate intrinsic value is calculated as the difference between the market value of our ordinary shares as of December 30, 2018 and the respective exercise prices of the options. The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018 , the last trading day prior to December 30, 2018 , as reported by the Nasdaq Global Select Market. The total intrinsic value of options exercised during 2018 and 2017 was $1.6 million and $0.3 million , respectively. No options were exercised during 2016 . A summary of our non-plan inducement stock options outstanding and exercisable at December 30, 2018 is as follows (shares in thousands): Options outstanding Options exercisable Range of exercise prices Number outstanding Weighted-average remaining Weighted-average exercise Number exercisable Weighted-average exercise $15.00 — $18.00 693 2.74 $ 15.66 693 $ 15.66 Employee Stock Purchase Plan The Wright Medical Group N.V. Amended and Restated Employee Stock Purchase Plan (the ESPP), which is an amended and restated version of the Tornier N.V. 2010 Employee Stock Purchase Plan, was approved by our shareholders on June 28, 2016. Under the ESPP, we are authorized to issue and sell up to the sum of (i) 333,333 ordinary shares registered previously under the Tornier N.V. 2010 Employee Stock Purchase Plan and (ii) 216,227 additional ordinary shares approved under the ESPP. The total of 550,000 ordinary shares are authorized to be issued to employees of our company and certain designated subsidiaries who work at least 20 hours per week. Under the ESPP, there are two six-month offering periods during each calendar year, one beginning January 1 and ending on June 30, and the other beginning July 1 and ending on December 31. However the compensation committee of the board of directors determined that the first offering period would be the three months beginning October 1, 2016 and ending December 31, 2016. Under the terms of the ESPP, each eligible employee can choose each offering period to have up to 20% of his or her eligible earnings withheld to purchase up to 1,000 ordinary shares. The purchase price of the shares is 85% of the market price on the first or last trading day of the offering period, whichever is lower. As of December 30, 2018 , there were 322,810 ordinary shares available for future issuance under the ESPP. Under the ESPP, the first offering period purchase occurred on December 31, 2016, which was during the 2017 fiscal year. In applying the Black-Scholes methodology to purchase rights granted under the ESPP, we used the following assumptions: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Risk-free interest rate 2.3% - 2.8% 1.3% - 1.9% 1.2% - 1.3% Expected life 6 months 6 months 3 months Expected price volatility 31% 24% 33%

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 30, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	Retirement Benefit Plans During the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , we offered a defined contribution retirement benefit plan for our U.S. based employees. Our defined contribution plan under Section 401(k) of the Internal Revenue Code of 1986, as amended (Code), covers U.S. employees who are 18 years of age and over. Under this plan, we have elected to make matching contributions to all eligible participants in an amount equal to 100% of the first three percent of eligible compensation, and 50% of the next two percent of eligible compensation, contributed to the Plan as deferral contributions. Employees are 100% vested in their rollover contributions, employer non-elective contributions, employer matching contributions, qualified non-elective contributions, deferral contributions, safe harbor matching employer contributions and any earnings thereon. The expense related to this plan recognized within our results from continuing operations was $6.2 million in 2018 , $5.5 million in 2017 , and $4.9 million in 2016 .

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases We lease certain equipment and office space under non-cancelable operating leases. Rental expense under operating leases approximated $11.1 million , $8.9 million , and $10.5 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. Future minimum payments, by year and in the aggregate, under non-cancelable operating leases with initial or remaining lease terms of one year or more, are as follows at December 30, 2018 (in thousands): 2019 $ 9,606 2020 7,498 2021 6,019 2022 4,433 2023 2,678 Thereafter 10,998 $ 41,232 Portions of our payments for operating leases are denominated in foreign currencies and were translated in the table above based on their respective U.S. dollar exchange rates at December 30, 2018 . These future payments are subject to foreign currency exchange rate risk. Purchase Obligations We have entered into certain supply agreements for our products which include minimum purchase obligations. As of December 30, 2018, we have minimum purchase obligations of $1.9 million , $1.3 million , $1.3 million for 2019, 2020, and 2021, respectively. In November 2018, we entered into a lease and other documents for the construction and lease of a 40,000 square foot state of the art facility in Arlington, Tennessee which will be used for manufacturing and distribution. The lease documents included an option to purchase this facility for approximately $12.0 million upon completion of construction. In December 2018, we exercised our option to purchase the facility once construction is complete. Legal Contingencies The legal contingencies described in this footnote relate primarily to WMT, an indirect subsidiary of Wright Medical Group N.V., and are not necessarily applicable to Wright Medical Group N.V. or other affiliated entities. Maintaining separate legal entities within our corporate structure is intended to ring-fence liabilities. We believe our ring-fenced structure should preclude corporate veil-piercing efforts against entities whose assets are not associated with particular claims. As described below, our business is subject to various contingencies, including patent and other litigation, product liability claims, and a government inquiry. These contingencies could result in losses, including damages, fines, or penalties, any of which could be substantial, as well as criminal charges. Although such matters are inherently unpredictable, and negative outcomes or verdicts can occur, we believe we have significant defenses in all of them, and are vigorously defending all of them. However, we could incur judgments, pay settlements, or revise our expectations regarding the outcome of any matter. Such developments, if any, could have a material adverse effect on our results of operations in the period in which applicable amounts are accrued, or on our cash flows in the period in which amounts are paid, however, unless otherwise indicated, we do not believe any of them will have a material adverse effect on our financial position. Our legal contingencies are subject to significant uncertainties and, therefore, determining the likelihood of a loss or the measurement of a loss can be complex. We have accrued for losses that are both probable and reasonably estimable. Unless otherwise indicated, we are unable to estimate the range of reasonably possible loss in excess of amounts accrued. Our assessment process relies on estimates and assumptions that may prove to be incomplete or inaccurate. Unanticipated events and circumstances may occur that could cause us to change our estimates and assumptions. Governmental Inquiries On August 3, 2012, we received a subpoena from the United States Attorney's Office for the Western District of Tennessee requesting records and documentation relating to the PROFEMUR ® series of hip replacement devices. The subpoena covers the period from January 1, 2000 to August 2, 2012. We will continue to cooperate as required. Patent Litigation On September 23, 2014, Spineology filed a patent infringement lawsuit, Case No. 0:14-cv-03767, in the U.S. District Court in Minnesota, alleging that our X-REAM ® bone reamer infringes U.S. Patent No. RE42,757 entitled “EXPANDABLE REAMER.” In January 2015, on the deadline for service of its complaint, Spineology dismissed its complaint without prejudice and filed a new, identical complaint. We filed an answer to the new complaint with the Court on April 27, 2015. The Court conducted a Markman hearing on March 23, 2016. Mediation was held on August 11, 2016, but no agreement could be reached. The Court issued a Markman decision on August 30, 2016, in which it found all asserted product claims invalid as indefinite under applicable patent laws and construed several additional claim terms. The parties completed fact and expert discovery with respect to the remaining asserted method claims. We filed a motion for summary judgment of non-infringement of the remaining asserted patent claims and motions to exclude testimony from Spineology’s technical and damages experts. Spineology filed a motion for summary judgment of infringement. On July 25, 2017, the Court granted our motion for summary judgment of non-infringement; denied Spineology’s motion for summary judgment of infringement; and denied all remaining motions as moot. The Court also entered judgment in our favor and against Spineology on all issues. Spineology appealed the judgment to the U.S. Court of Appeals for the Federal Circuit and on July 6, 2018, the Court of Appeals affirmed the judgment of non-infringement in our favor and directed the District Court to enter judgment of non-infringement as to all of Spineology’s asserted patent claims. On September 6, 2018, the Court of Appeals denied Spineology’s petition for rehearing and, on September 18, 2018, the District Court entered final judgment of non-infringement. On September 13, 2016, we filed a civil action, Case No. 2:16-cv-02737-JPM, against Spineology in the U.S. District Court for the Western District of Tennessee alleging breach of contract, breach of implied warranty against infringement, and seeking a judicial declaration of indemnification from Spineology for patent infringement claims brought against us stemming from our sale and/or use of certain expandable reamers purchased from Spineology. Spineology filed a motion to dismiss on October 17, 2016, but withdrew the motion on November 28, 2016. On December 7, 2016, Spineology filed an answer to our complaint and counterclaims, including counterclaims relating to a 2004 non-disclosure agreement between Spineology and WMT. On December 28, 2016, we filed a motion to dismiss the counterclaims relating to that 2004 agreement. On January 4, 2017, Spineology filed a motion for summary judgment on certain claims set forth in our complaint. We opposed that motion. On January 27, 2017, we filed a motion for summary judgment on certain issues pertaining to our indemnification claims. Spineology opposed that motion. On July 7, 2017, the Court extended the deadlines for completing discovery until after it ruled on those pending motions. On August 29, 2017, the Court ruled on the motions to dismiss and for summary judgment. In view of that decision, on September 22, 2017, the parties stipulated to, and the Court entered, a judgment that effectively ended the case in a draw. We have appealed the judgment as to our claims against Spineology to the U.S. Court of Appeals for the Sixth Circuit and oral argument occurred on August 2, 2018. On August 24, 2018, the Court of Appeals ruled in our favor on our breach of contract claim and remanded the case to the District Court for further proceedings. Spineology did not appeal the District Court’s dismissal of its contract counterclaim. We have reached an agreement in principle with Spineology to settle our breach of contract claim pursuant to which Spineology will pay us an immaterial amount. Product Liability We have received claims for personal injury against us associated with fractures of the PROFEMUR ® titanium modular neck product (PROFEMUR ® Claims). As of December 30, 2018, there were approximately 19 unresolved pending U.S. lawsuits and approximately 57 unresolved pending non-U.S. lawsuits alleging such claims. The overall fracture rate for the product is low and the fractures appear, at least in part, to relate to patient demographics. Beginning in 2009, we began offering a cobalt-chrome version of the PROFEMUR ® modular neck, which has greater strength characteristics than the alternative titanium version. Historically, we have reflected our liability for these claims as part of our standard product liability accruals on a case-by-case basis. However, during the fiscal quarter ended September 30, 2011, as a result of an increase in the number and monetary amount of these claims, management estimated our liability to patients in the United States and Canada who have previously required a revision following a fracture of a PROFEMUR ® titanium modular neck, or who may require a revision in the future. Management has estimated that the aggregate liability is $17.5 million . We have classified $12.3 million of this liability as current in “Accrued expenses and other current liabilities,” as we expect to pay such claims within the next twelve months, and $5.2 million as non-current in “Other liabilities” on our consolidated balance sheet. We expect to pay the majority of these claims within the next three years. Any claims associated with this product outside of the United States and Canada, or for any other products, will be managed as part of our standard product liability accrual methodology on a case-by-case basis. We have maintained product liability insurance coverage on a claims-made basis. During the fiscal quarter ended March 31, 2013, we received a customary reservation of rights from our primary product liability insurance carrier asserting that present and future claims related to fractures of the PROFEMUR ® titanium modular neck hip products and which allege certain types of injury (Titanium Modular Neck Claims) would be covered as a single occurrence under the policy year the first such claim was asserted. The effect of this coverage position would be to place Titanium Modular Neck Claims into a single prior policy year in which applicable claims-made coverage was available, subject to the overall policy limits then in effect. Management agreed with the assertion that the Titanium Modular Neck Claims should be treated as a single occurrence, but notified the carrier that it disputed the carrier's selection of available policy years. During the second quarter of 2013, we received confirmation from the primary carrier confirming their agreement with our policy year determination. Based on our insurer's treatment of Titanium Modular Neck Claims as a single occurrence, we increased our estimate of the total probable insurance recovery related to Titanium Modular Neck Claims by $19.4 million , and recognized such additional recovery as a reduction to our selling, general and administrative expenses for the fiscal quarter ended March 31, 2013, within results of discontinued operations. In the fiscal quarter ended June 30, 2013, we received payment from the primary insurance carrier of $5 million . In the fiscal quarter ended September 30, 2013, we received payment of $10 million from the next insurance carrier in the tower. We requested, but did not receive, payment of the remaining $25 million from the third insurance carrier in the tower for that policy period. The policies with the second and third carrier in this tower are “follow form” policies and management believed the third carrier should follow the coverage position taken by the primary and secondary carriers. On September 29, 2015, that third carrier asserted that the terms and conditions identified in its reservation of rights would preclude coverage for the Titanium Modular Neck Claims. Pursuant to applicable accounting standards, we reduced our insurance receivable balance for this claim to $0 , and recorded a $25 million charge within “Net loss from discontinued operations” during the fiscal year ended December 27, 2015. We strongly disputed the carrier's position and, in accordance with the dispute resolution provisions of the policy, initiated an arbitration proceeding in London, England seeking payment of these funds. The arbitration proceeding was completed on February 15, 2018 and on April 11, 2018, the arbitration tribunal issued its ruling. Thereafter, we and the insurance carrier agreed to resolve the entire matter in exchange for a single lump sum payment by the carrier to us in the amount of $30.75 million , representing the full policy limits of $25 million plus an additional $5.75 million for legal costs and interest. We received payment of this sum from the carrier on May 8, 2018. This insurance recovery is reflected within our results of discontinued operations for 2018. We are aware that MicroPort has recalled a certain size of its cobalt chrome modular neck product as a result of alleged fractures. As of December 30, 2018, there were eleven pending U.S. lawsuits and six pending non-U.S. lawsuits against us alleging personal injury resulting from the fracture of a cobalt chrome modular neck. These claims will be managed as part of our standard product liability accrual methodology on a case-by-case basis. Claims for personal injury have also been made against us associated with metal-on-metal hip products (primarily the CONSERVE ® product line). The pre-trial management of certain of these claims was consolidated in the federal court system, in the United States District Court for the Northern District of Georgia under multi-district litigation (MDL) and certain other claims by the Judicial Counsel Coordinated Proceedings in state court in Los Angeles County, California (JCCP) in state court in Los Angeles County, California (collectively the Consolidated Metal-on-Metal Claims). Pursuant to previously disclosed settlement agreements with the Court-appointed attorneys representing plaintiffs in the MDL and JCCP described below, the MDL and JCCP were closed to new cases effective October 18, 2017 and October 31, 2017, respectively. Excluding claims resolved in the settlement agreements described below, as of December 30, 2018, there were approximately 151 unresolved metal-on-metal hip cases pending in the U.S. This number includes cases ineligible for settlement, cases which opted out of settlement, post-settlement cases, tolled cases, and existing state court cases that were not part of the MDL or JCCP. As of December 30, 2018, we estimate there also were pending approximately 33 unresolved non-U.S. metal-on metal cases, 35 unresolved U.S. modular neck cases alleging claims related to the release of metal ions, and zero non-U.S. modular neck cases with such metal ion allegations. We also estimate that as of December 30, 2018 there were approximately 534 non-revision claims either dismissed or awaiting dismissal from the MDL and JCCP pursuant to the terms of the settlement agreements. Although there is a limited time period during which dismissed non-revision claims may be refiled, it is presently unclear how many non-revision claimants will elect to do so. As of December 30, 2018, one dismissed non-revision case has been refiled. We believe we have data that supports the efficacy and safety of these hip products. Every hip implant case, including metal-on-metal hip cases, involves fundamental issues of law, science, and medicine that often are uncertain, that continue to evolve, and which present contested facts and issues that can differ significantly from case to case. Such contested facts and issues include medical causation, individual patient characteristics, surgery specific factors, statutes of limitation, and the existence of actual, provable injury. On November 1, 2016, WMT entered into the MSA with Court-appointed attorneys representing plaintiffs in the MDL and JCCP. Under the terms of the MSA, the parties agreed to settle 1,292 specifically identified claims associated with CONSERVE ® , DYNASTY ® and LINEAGE ® products that meet the eligibility requirements of the MSA and are either pending in the MDL or JCCP, or subject to court-approved tolling agreements in the MDL or JCCP, for a settlement amount of $240 million . The $240 million settlement amount is a maximum settlement based on the pool of 1,292 specific, existing claims comprised of an identified mix of CONSERVE ® , DYNASTY ® and LINEAGE ® products (Initial Settlement Pool), with a value assigned to each product type, resulting in a total settlement of $240 million for the 1,292 claims in the Initial Settlement Pool. Actual settlements paid to individual claimants are determined under the claims administration procedures contained in the MSA and may be more or less than the amounts used to calculate the $240 million settlement for the 1,292 claims in the Initial Settlement Pool. However in no event will variations in actual settlement amounts payable to individual claimants affect WMT’s maximum settlement obligation of $240 million or the manner in which it may be reduced due to opt outs, final product mix, or elimination of ineligible claims. Claims in the Initial Settlement Pool that were ineligible due to failure to meet the eligibility criteria of the MSA were replaced with new eligible claims involving the same product, so that the number and mix of claims in the final settlement pool (before opt-outs) (Final Settlement Pool) equaled the number and mix of claims in the Initial Settlement Pool. Additionally, where DYNASTY ® or LINEAGE ® claims in the Final Settlement Pool were determined to have been misidentified as CONSERVE ® claims, or vice versa, the total settlement amount was adjusted based on the value for each product type (not to exceed $240 million). The MSA contains specific eligibility requirements and establishes procedures for proof and administration of claims, negotiation and execution of individual settlement agreements, determination of the final total settlement amount, and funding of individual settlement amounts by WMT. Eligibility requirements include, without limitation, that the claimant has a claim pending or tolled in the MDL or JCCP, that the claimant has undergone a revision surgery within eight years of the original implantation surgery, and that the claim has not been identified by WMT as having possible statute of limitation issues. Claimants who have had bilateral revision surgeries will be counted as two claims but only to the extent both claims separately satisfy all eligibility criteria. The MSA includes a 95% opt-in requirement, meaning the MSA could have been terminated by WMT prior to any settlement disbursement if claimants holding greater than 5% of eligible claims in the Final Settlement Pool elected to “opt-out” of the settlement. WMT has confirmed that of the 1,292 eligible claims, 1,279 opted to participate in the settlement and 13 opted out, resulting in a final opt-in percentage of approximately 99%, well in excess of the required 95% threshold. On March 2, 2017, WMT agreed to replace the 13 opt-out claims with 13 additional claims that would have been eligible to participate in the MSA but for the 1,292 claim limit, bringing the total MSA settlement to the maximum limit of $240 million to settle 1,292 claims. Due to apparent demand from additional claimants excluded from settlement because of the 1,292 claims ceiling, but otherwise eligible for participation, on May 5, 2017, WMT agreed to settle an additional 53 such claims, on terms substantially identical to the MSA settlement terms, for a maximum additional settlement amount of $9.4 million . During 2016, WMT escrowed $150 million to secure its obligations under the MSA, all of which had been disbursed as of December 31, 2017. As additional security, Wright Medical Group N.V., the indirect parent company of WMT, agreed to guarantee WMT’s obligations under the MSA. On October 3, 2017, WMT entered into the Second Settlement Agreements with the Court-appointed attorneys representing plaintiffs in the MDL and JCCP. Under the terms of the Second Settlement Agreements, the parties agreed to settle 629 specifically identified CONSERVE ® , DYNASTY ® and LINEAGE ® claims that meet the eligibility requirements of the Second Settlement Agreements and are either pending in the MDL or JCCP, or subject to court-approved tolling agreements in the MDL or JCCP, for a maximum settlement amount of $89.75 million. The comprehensive settlement amount was contingent on WMT’s recovery of new insurance proceeds totaling at least $35 million from applicable insurance carriers by December 31, 2017. On December 29, 2017, WMT entered into a First Amendment to the Third Settlement Agreement pursuant to which the deadline for the recovery of new insurance proceeds totaling at least $35 million from applicable insurance carriers was extended through February 28, 2018 and, on February 23, 2018, WMT entered into a Second Amendment to the Third Settlement Agreement pursuant to which the deadline was extended through March 30, 2018. On March 29, 2018, WMT entered into a Third Amendment to the Third Settlement Agreement which eliminated the contingency and gave WMT the option, by September 30, 2018, to either pay or make available for payment the then outstanding deficit on the insurance contingency or transfer to eligible claimants WMT’s claims against the insurance carriers with whom WMT has not settled, and pay or make available for payment such insurance deficit in March 2019, subject to the right to recover these funds from any plaintiff recoveries from carriers plus ten percent interest, plus an additional $5 million in costs, in each case after recovery by plaintiffs’ counsel of costs and fees. In connection with such transfer agreement, WMT would also enter into a stipulated judgment in the amount of $541 million, which judgment would not be recoverable against WMT or its affiliates. On September 27, 2018, WMT elected not to transfer WMT’s claims against the insurance carriers with whom WMT has not settled. The $89.75 million settlement amount is a maximum settlement based on the pool of 629 specific, existing claims comprised of an identified mix of CONSERVE ® , DYNASTY ® and LINEAGE ® products (Second Settlement Initial Settlement Pool), with a value assigned to each product type. Actual settlements paid to individual claimants will be determined under the claims administration procedures contained in the Second Settlement Agreements and may be more or less than the amounts used to calculate the $89.75 million settlement for the 629 claims in the Second Settlement Initial Settlement Pool. However in no event will variations in actual settlement amounts payable to individual claimants affect WMT’s maximum settlement obligation of $89.75 million or the manner in which it may be reduced due to opt outs, final product mix, or elimination of ineligible claims. The total maximum settlement amount of $89.75 million is allocated among the following three tranches: (1) Tranche 1: $7.9 million to settle 49 additional claims that would have been eligible to participate in the MSA but for the claim limit contained therein, which amount will be funded as such claims are settled; (2) Tranche 2: $5.1 million to settle 39 eligible claims of the oldest claimants (by age), which amount will be funded as such claims are settled; and (3) Tranche 3: $76.75 million to settle 511 eligible claims pending or tolled in the MDL and JCCP existing as of June 30, 2017, and 30 new eligible claims which were presented between July 1, 2017 and October 1, 2017, Settlement funds for Tranche 3 were or will be made available for payment as follows: $45 million (less the remaining insurance deficit, which was $13.1 million ) on June 30, 2018, the remaining insurance deficit ($13.1 million) by September 30, 2018, and the balance by September 30, 2019. Funding of the Second Settlement Agreements has begun and $41.9 million was funded as of December 30, 2018. The Second Settlement Agreements contain specific eligibility requirements and establish procedures for proof and administration of claims, negotiation and execution of individual settlement agreements, determination of the final total settlement amount, and funding of individual settlement amounts by WMT. Eligibility requirements include, without limitation, that the claimant has a claim pending or tolled in the MDL or JCCP and that, with limited exceptions, the claimant has undergone a revision surgery. Claimants who have had bilateral revision surgeries will be counted as two claims but only to the extent both claims separately satisfy all eligibility criteria. Each of the Second Settlement Agreements includes a 95% opt-in requirement, meaning WMT could have terminated either Settlement Agreement prior to any settlement disbursement if claimants holding greater than 5% of eligible claims in Tranches 1 and 2, collectively, or claimants holding greater than 5% of eligible claims in Tranche 3, elected to “opt-out” of the settlement. On January 2, 2018, WMT received notification that 100% of the claimants in Tranches 1 and 2 opted-in. WMT reviewed proof of claim documentation for these claimants and confirmed a final opt-in percentage of 100%. On or about May 1, 2018, WMT received notice from plaintiffs that the 95% opt-in threshold had also been met for Tranche 3. WMT reviewed proof of claim documentation for Tranche 3 claimants and confirmed that the 95% opt-in threshold had been met. On July 31, 2018, WMT confirmed a final opt-in percentage of 100% for Tranche 3. While the Second Settlement Agreements did not require WMT to escrow any amount to secure its obligations thereunder, as additional security, Wright Medical Group N.V., the indirect parent company of WMT, agreed to guarantee WMT’s obligations under the Second Settlement Agreements. The MSA (which reference includes the supplemental settlements described above) and the Second Settlement Agreements were entered into solely as a compromise of the disputed claims being settled and are not evidence that any claim has merit nor are they an admission of wrongdoing or liability by WMT. WMT will continue to vigorously defend metal-on-metal hip claims not settled pursuant to the above agreements. The Second Settlement Agreements are contingent upon the dismissal without prejudice of pending and tolled claims in the MDL and JCCP that do not meet the inclusion criteria of the MDL or JCCP. Additionally, the Second Settlement Agreements are contingent upon the dismissal without prejudice of all remaining non-revision claims in the MDL and JCCP (presently estimated to number approximately 534 claims either dismissed or awaiting dismissal), pursuant to a tolling agreement that tolls applicable statutes of limitation and repose for three months from a revision of the products or determination that a revision of the products is necessary. The MDL and JCCP courts have both entered orders closing these proceedings to new claims. As a result of entering into the Second Settlement Agreements during the third quarter of 2017, we recorded an additional accrual of $82.7 million for the 629 matters included within the settlement and for matters that have the same eligibility criteria. As of December 30, 2018, our accrual for metal-on-metal claims totaled $74.5 million , of which $51.9 million is included in our consolidated balance sheet within “Accrued expenses and other current liabilities” and $22.6 million is included within “Other liabilities.” Our accrual is based on (i) case by case accruals for specific cases where facts and circumstances warrant, and (ii) the implied settlement values for eligible claims under the MSA or Second Settlement Agreements. We are unable to reasonably estimate the high-end of a possible range of loss for claims which elected to opt-out of the MSA or Second Settlement Agreements. Claims we can confirm would meet MSA or Second Settlement Agreements eligibility criteria but are excluded from the settlements due to the maximum settlement cap, or because they are cases not part of the MDL or JCCP, have been accrued as of the respective settlement rates. Due to the general uncertainties surrounding all metal-on metal claims as noted above, as well as insufficient information about individual claims, we are presently unable to reasonably estimate a range of loss for future claims; hence we have not accrued for these claims at the present time. We continue to believe the high-end of a possible range of loss for existing revision claims that do not meet eligibility criteria of the MSA or Second Settlement Agreements will not, on an average per case basis, exceed the average per case accrual we take for revision claims we can confirm do meet eligibility criteria of the MSA or Second Settlement Agreements, as applicable. Future claims will be evaluated for accrual on a case by case basis using the accrual methodologies described above (which could change if future facts and circumstances warrant). The first state court metal-on-metal hip trial not part of the MDL or JCCP commenced on October 24, 2016, in St. Louis, Missouri. On November 3, 2016, the jury returned a verdict in our favor. The plaintiff appealed, and the appellate court heard oral argument on November 8, 2017. On February 20, 2018, the Missouri Court of Appeals, Eastern District, denied the plaintiff’s appeal and upheld the verdict of the trial court. The plaintiff’s time for seeking any further relief from the verdict has lapsed and this matter is closed. We have maintained product liability insurance coverage on a claims-made basis. During the fiscal quarter ended September 30, 2012, we received a customary reservation of rights from our primary product liability insurance carrier asserting that certain present and future claims which allege certain types of injury related to the CONSERVE ® metal-on-metal hip products (CONSERVE ® Claims) would be covered as a single occurrence under the policy year the first such claim was asserted. The effect of this coverage position would be to place CONSERVE ® Claims into a single prior policy year in which applicable claims-made coverage was available, subject to the overall policy limits then in effect. Management agrees that there is insurance coverage for the CONSERVE ® Claims, but has notified the carrier that it disputes the carrier's characterization of the CONSERVE ® Claims as a single occurrence. In June 2014, Travelers, which was an excess carrier in our coverage towers across multiple policy years, filed a declaratory judgment action in Tennessee state court naming us and certain of our other insurance carriers as defendants and asking the court to rule on the rights and responsibilities of the parties with regard to the CONSERVE ® Claims. Among other things, Travelers appeared to dispute our contention that the CONSERVE ® Claims arise out of more than a single occurrence thereby triggering multiple policy periods of coverage. Travelers further sought a determination as to the applicable policy period triggered by the alleged single occurrence. We filed a separate lawsuit in state court in California for declaratory judgment against certain carriers and breach of contract against the primary carrier and moved to dismiss or stay the Tennessee action on a number of grounds, including that California is the most appropriate jurisdiction. During the third quarter of 2014, the California Court granted Travelers' motion to stay our California action. On October 28, 2016, WMT and Wright Medical Group, Inc. (Wright Entities) entered into a Settlement Agreement, Indemnity and Hold Harmless Agreement and Policy Buyback Agreement (Insurance Settlement Agreement) with a subgroup of three insurance carriers, namely Columbia Casualty Company, Travelers and AXIS Surplus Lines Insurance Company (collectively, the Three Settling Insurers), pursuant to which the Three Settling Insurers paid WMT an aggregate of $60 million (in addition to $10 million previously paid by Columbia) in a lump sum. This amount is in full satisfaction of all potential liability of the Three Settling Insurers relating to metal-on-metal hip and similar metal ion release claims, including but not limited to all claims in the MDL and the JCCP, and all claims asserted by WMT against the Three Settling Insurers in the Tennessee action described above. As part of the settlement with the Three

Quarterly Results of Operations

Quarterly Results of Operations	12 Months Ended
	Dec. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (unaudited)	Quarterly Results of Operations (unaudited): The following tables present a summary of our unaudited quarterly operating results for each of the four quarters in 2018 and 2017 , respectively (in thousands). This information was derived from unaudited interim financial statements that, in the opinion of management, have been prepared on a basis consistent with the financial statements contained elsewhere in this report and include all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of such information when read in conjunction with our audited financial statements and related notes. The operating results for any quarter are not necessarily indicative of results for any future period. 2018 First quarter Second quarter Third quarter Fourth quarter Net sales $ 198,537 $ 205,400 $ 194,106 $ 238,147 Cost of sales 41,139 45,558 44,307 49,149 Gross profit 157,398 159,842 149,799 188,998 Operating expenses: Selling, general and administrative 137,248 140,826 139,223 160,664 Research and development 13,899 14,665 13,829 16,749 Amortization of intangible assets 7,141 6,009 5,881 7,699 Total operating expenses 158,288 161,500 158,933 185,112 Operating (loss) income (890 ) (1,658 ) (9,134 ) 3,886 Net loss from continuing operations, net of tax (19,907 ) (90,621 ) (35,829 ) (22,947 ) (Loss) income from discontinued operations, net of tax (5,607 ) 22,923 (6,696 ) (10,821 ) Net loss $ (25,514 ) $ (67,698 ) $ (42,525 ) $ (33,768 ) Net loss, continuing operations per share, basic and diluted $ (0.19 ) $ (0.85 ) $ (0.32 ) $ (0.18 ) Net loss income per share, basic and diluted $ (0.24 ) $ (0.64 ) $ (0.38 ) $ (0.27 ) Weighted-average number of shares outstanding-basic and diluted 105,904 106,095 113,043 125,323 Our 2018 operating (loss) income included the following: • transaction and transition costs totaling $0.9 million , $1.3 million , $2.0 million , and $7.8 million during the first, second, third, and fourth quarters of 2018 , respectively; and • amortization of inventory step-up of $0.4 million in the fourth quarter of 2018 associated with inventory acquired from the Cartiva acquisition. Our 2018 net loss from continuing operations included the following: • the after-tax effect of the above amounts within operating (loss) income; • the after-tax effects of non-cash interest expense related to the amortization of the debt discount on our 2020 Notes, 2021 Notes and 2023 Notes totaling $12.0 million , $12.3 million , $12.3 million , and $12.6 million during the first, second, third, and fourth quarters of 2018 , respectively; • the after-tax effects of a $39.9 million non-cash loss on extinguishment of debt to write-off unamortized debt discount and deferred financing fees associated with the partial settlement of the 2020 Notes during the second quarter of 2018 ; • the after-tax effects of our mark-to-market adjustments on derivative assets and liabilities totaling a $1.7 million loss, $32.9 million loss, $0.2 million gain, and $1.6 million loss recognized in the first, second, third, and fourth quarters of 2018 , respectively; • the after-tax effects of non-cash foreign currency translation charges of $0.8 million , $1.9 million , $0.2 million , and $0.3 million during the first, second, third, and fourth quarters of 2018 , respectively; • the after-tax effects of our fair value adjustments to contingent consideration totaling a $0.4 million loss, $0.4 million loss, $0.3 million loss, and $0.7 million loss in the first, second, third, and fourth quarters of 2018 , respectively; • the after-tax effects of our CVR mark-to-market adjustments of $3.9 million gain, $2.5 million gain, $3.4 million loss, and $3.2 million loss recognized in the first, second, third, and fourth quarters of 2018 , respectively; • a tax benefit related to the realizability of deferred tax assets as result of the Cartiva acquisition of $3.6 million in the fourth quarter of 2018 ; • a tax provision of $2.7 million due to a change in judgment regarding our ability to realize certain deferred tax assets in the fourth quarter of 2018; and • a U.S. tax (benefit) provision within continuing operations recorded as a result of the pre-tax gain recognized within discontinued operations due to the $30.75 million insurance settlement totaling $(6.2) million , $2.2 million , and $3.8 million in the second, third, and fourth quarters of 2018 , respectively. 2017 First Second Third Fourth Net sales $ 177,191 $ 179,693 $ 170,503 $ 217,602 Cost of sales 37,126 38,122 38,421 47,278 Gross profit 140,065 141,571 132,082 170,324 Operating expenses: Selling, general and administrative 129,834 130,818 131,421 133,149 Research and development 12,432 12,547 11,992 13,144 Amortization of intangible assets 7,397 6,999 7,178 6,822 Total operating expenses 149,663 150,364 150,591 153,115 Operating (loss) income (9,598 ) (8,793 ) (18,509 ) 17,209 Net (loss) income from continuing operations, net of tax (36,707 ) (20,960 ) (34,122 ) 26,852 (Loss) income from discontinued operations, net of tax (21,992 ) (20,202 ) (97,748 ) 2,281 Net (loss) income $ (58,699 ) $ (41,162 ) $ (131,870 ) $ 29,133 Net (loss) income, continuing operations per share, basic $ (0.35 ) $ (0.20 ) $ (0.33 ) $ 0.26 Net (loss) income, continuing operations per share, diluted $ (0.35 ) $ (0.20 ) $ (0.33 ) $ 0.25 Net (loss) income per share, basic $ (0.57 ) $ (0.39 ) $ (1.26 ) $ 0.28 Net (loss) income per share, diluted $ (0.57 ) $ (0.39 ) $ (1.26 ) $ 0.27 Weighted-average number of shares outstanding-basic 103,663 104,377 104,836 105,195 Weighted-average number of shares outstanding-diluted 103,663 104,377 104,836 106,578 Our 2017 operating (loss) income included the following: • transaction and transition costs totaling $3.0 million , $3.2 million , $3.3 million , and $2.9 million during the first, second, third, and fourth quarters of 2017 , respectively; and • a benefit from incentive and indirect tax projects of $9.0 million in the fourth quarter of 2017 . Our 2017 net (loss) income from continuing operations included the following: • the after-tax effect of the above amounts within operating (loss) income; • the after-tax effects of our CVR mark-to-market adjustments of $6.2 million loss, $3.9 million gain, $4.5 million loss, and $1.4 million gain recognized in the first, second, third, and fourth quarters of 2017 , respectively; • the after-tax effects of non-cash interest expense related to the amortization of the debt discount on our 2017 Notes, 2020 Notes and 2021 Notes totaling $11.0 million , $11.2 million , $11.5 million , and $11.7 million during the first, second, third, and fourth quarters of 2017 , respectively; • the after-tax effects of our mark-to-market adjustments on derivative assets and liabilities totaling a $0.4 million loss, $4.3 million gain, $0.2 million gain, and $0.6 million gain recognized in the first, second, third, and fourth quarters of 2017 , respectively; • the after-tax effects of our fair value adjustments to contingent consideration totaling a $0.2 million loss, $0.1 million loss, and $0.2 million gain in the second, third, and fourth quarters of 2017 , respectively; • a tax benefit related to the realizability of net operating losses of $8.9 million and $16.0 million in the third and fourth quarters of 2017 , respectively; • the tax effects of tax law reform in the U.S. and France totaling $8.3 million in the fourth quarter of 2017 ; and • the tax effects of a benefit from incentive and indirect tax projects of $0.8 million in the fourth quarter of 2017 .

Segment Data

Segment Data	12 Months Ended
	Dec. 30, 2018
Segment Data [Abstract]
Segment Data	Segment and Geographic Data During the first quarter of 2016, our management, including our Chief Executive Officer, who is our chief operating decision maker, began managing our operations as four operating business segments: U.S. Lower Extremities & Biologics, U.S. Upper Extremities, International Extremities & Biologics, and Large Joints. We determined that each of these operating segments represented a reportable segment. Our Chief Executive Officer reviews financial information at the operating segment level to allocate resources and to assess the operating results and performance of each segment. As a result of the classification of the Large Joints business as a discontinued operation during the second quarter of 2016, the Large Joints reportable segment is presented in our consolidated statements of operations as discontinued operations and is excluded from segment results for all periods presented. See Note 4 of the consolidated financial statements for additional information regarding this divestiture. U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics are our remaining three reportable segments as of December 30, 2018 . Our U.S. Lower Extremities & Biologics segment consists of our operations focused on the sale in the United States of our lower extremities products, such as joint implants and bone fixation devices for the foot and ankle, and our biologics products used to support treatment of damaged or diseased bone, tendons, and soft tissues or to stimulate bone growth. Our U.S. Upper Extremities segment consists of our operations focused on the sale in the United States of our upper extremities products, such as joint implants and bone fixation devices for the shoulder, elbow, wrist, and hand and products used across several anatomic sites to mechanically repair tissue-to-tissue or tissue-to-bone injuries and other ancillary products. As the IMASCAP operations are managed by the U.S. Upper Extremities management team, results of operations and assets related to IMASCAP are included within the U.S. Upper Extremities segment. Our International Extremities and Biologics segment consists of our operations focused on the sale outside the United States of all lower and upper extremities products, including associated biologics products. Management measures segment profitability using an internal operating performance measure that excludes the impact of inventory step-up amortization and transaction and transition costs associated with acquisitions, as such items are not considered representative of segment results. We have determined that each reportable segment represents a reporting unit and, in accordance with ASC 350, requires an allocation of goodwill to each reporting unit. As of December 30, 2018 , we have allocated $570.0 million , $627.9 million , and $71.1 million of goodwill to the U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics reportable segments, respectively. Our principal geographic regions consist of the United States, EMEAC (which includes Europe, the Middle East, Africa, and Canada), and Other (which principally represents Asia, Australia, and Latin America). Net sales attributed to each geographic region are based on the location in which the products were sold. Net sales by geographic region by product line are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 United States Lower extremities $ 250,735 $ 228,044 $ 222,936 Upper extremities 281,314 239,965 201,579 Biologics 83,077 78,361 74,603 Sports med & other 8,412 8,141 8,429 Total United States $ 623,538 $ 554,511 $ 507,547 EMEAC Lower extremities $ 46,342 $ 42,333 $ 43,805 Upper extremities 87,647 73,243 66,819 Biologics 8,312 8,445 8,149 Sports med & other 11,074 13,751 13,405 Total EMEAC $ 153,375 $ 137,772 $ 132,178 Other Lower extremities $ 14,407 $ 16,140 $ 18,896 Upper extremities 26,813 21,456 19,683 Biologics 17,445 13,831 10,734 Sports med & other 612 1,279 1,324 Total other $ 59,277 $ 52,706 $ 50,637 Total net sales $ 836,190 $ 744,989 $ 690,362 No single foreign country accounted for more than 10% of our total net sales during 2018 , 2017 , or 2016 . Assets in the U.S. Upper Extremities, U.S. Lower Extremities & Biologics, and International Extremities & Biologics segments are those assets used exclusively in the operations of each business segment or allocated when used jointly. Assets in the Corporate category are principally cash and cash equivalents, derivative assets, property, plant and equipment associated with our corporate headquarters, assets associated with discontinued operations, product liability insurance receivables, and assets associated with income taxes. Total assets by business segment as of December 30, 2018 and December 31, 2017 are as follows (in thousands): December 30, 2018 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate Total Total assets $ 940,075 $ 923,036 $ 272,127 $ 559,163 $ 2,694,401 December 31, 2017 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate Total Total assets $ 490,528 $ 929,930 $ 301,985 $ 406,281 $ 2,128,724 Selected financial information related to our segments is presented below for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 (in thousands): Fiscal year ended December 30, 2018 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 337,433 $ 286,105 $ 212,652 $ — $ 836,190 Depreciation expense 11,131 12,439 13,004 22,923 59,497 Amortization expense — — — 26,730 26,730 Segment operating income (loss) $ 96,153 $ 97,644 $ 1,492 $ (190,720 ) $ 4,569 Other: Transaction and transition expenses 12,013 Inventory step-up amortization 352 Operating loss (7,796 ) Interest expense, net 80,247 Other expense, net 81,797 Loss before income taxes $ (169,840 ) Capital expenditures $ 21,153 $ 26,346 $ 17,566 $ 6,402 $ 71,467 Fiscal year ended December 31, 2017 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 309,713 $ 244,798 $ 190,478 $ — $ 744,989 Depreciation expense 12,532 10,211 12,366 21,723 56,832 Amortization expense — — — 28,396 28,396 Segment operating income (loss) $ 79,889 $ 78,866 $ 3,631 $ (178,642 ) $ (16,256 ) Other: Transaction and transition expenses 12,400 Incentive and indirect tax projects (8,965 ) Operating loss (19,691 ) Interest expense, net 74,644 Other expense, net 5,570 Loss before income taxes $ (99,905 ) Capital expenditures $ 19,355 $ 22,897 $ 19,555 $ 1,667 $ 63,474 Fiscal year ended December 25, 2016 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 300,847 $ 206,700 $ 182,815 $ — $ 690,362 Depreciation expense 13,000 11,190 11,427 20,213 55,830 Amortization expense — — — 28,841 28,841 Segment operating income (loss) $ 85,645 $ 65,231 $ 5,872 $ (202,261 ) $ (45,513 ) Other: Inventory step-up amortization 37,689 Transaction and transition expenses 36,374 Legal settlement 1,800 Management changes 1,348 Costs associated with new convertible debt 234 Operating loss (122,958 ) Interest expense, net 58,530 Other income, net (3,148 ) Loss before income taxes $ (178,340 ) Capital expenditures $ 13,145 $ 10,101 $ 13,517 $ 13,336 $ 50,099 1 The Corporate category primarily reflects general and administrative expenses not specifically associated with the U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics segments. These non-allocated corporate expenses relate to global administrative expenses that support all segments, including salaries and benefits of certain executive officers and expenses such as: information technology administration and support; corporate headquarters; legal, compliance, and corporate finance functions; insurance; and all share-based compensation.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 30, 2018
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Wright Medical Group N.V. Schedule II-Valuation and Qualifying Accounts (In thousands) Balance at Beginning of Period Charged to Cost and Expenses Deductions and Other Balance at End of Period Allowance for doubtful accounts: For the period ended: December 30, 2018 $ 4,328 $ 189 $ (1,472 ) $ 3,045 December 31, 2017 $ 4,469 $ 1,243 $ (1,384 ) $ 4,328 December 25, 2016 $ 1,189 $ 3,475 $ (195 ) $ 4,469

Subsequent Event (Notes)

Subsequent Event (Notes)	12 Months Ended
	Dec. 30, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events 2020 Notes Exchange On February 7, 2019, WMG issued $139.6 million aggregate principal amount of the 2023 Notes pursuant to the 2023 Notes Indenture (Additional 2023 Notes). The Additional 2023 Notes were delivered to certain accredited investors (within the meaning of Rule 501 promulgated under the Securities Act) and/or qualified institutional buyers (as defined in Rule 144A under the Securities Act) in exchange for $130.1 million aggregate principal amount of 2020 Notes. We fully and unconditionally guarantee the Additional 2023 Notes on a senior unsecured basis. For each $1,000 principal amount of 2020 Notes validly submitted for exchange, WMG delivered $1,072.40 principal amount of Additional 2023 Notes to the exchanging investor (subject, in each case, to rounding to the nearest $1,000 aggregate principal amount for each such exchanging investor). There was no separate cash payment in respect of rounded amounts or interest, if any, accrued and unpaid to the closing date of the exchange. The Additional 2023 Notes are referred to as “exchangeable” in the exchange documents because were issued by WMG, not us. Neither we nor WMG received any cash proceeds from the exchange of 2020 Notes for the Additional 2023 Notes. After giving effect to the issuance of the Additional 2023 Notes and the exchange of the 2020 Notes and the issuance of 2023 Notes pursuant to the exchange that occurred in June 2018, $814.6 million aggregate principal amount of the 2023 Notes is currently issued and outstanding under the Indenture and $56.5 million aggregate principal amount of the 2020 Notes remains issued and outstanding. In connection with the above-described exchange, on January 30, 2019 and January 31, 2019, we, along with WMG, entered into cash-settled convertible note hedge transactions with two counterparties, Deutsche Bank AG, London Branch and JPMorgan Chase Bank, National Association (Option Counterparties), which are expected generally to reduce the net cash payments that WMG may be required to make upon conversion of the Additional 2023 Notes to the extent that such cash payments exceed the principal amount of the Additional 2023 Notes and the per share market price of our ordinary shares, as measured under the terms of the cash convertible note hedge transactions, is greater than the strike price of the cash convertible note hedge transactions, which is initially $33.37 , corresponding to the initial conversion price of the Additional 2023 Notes, and is subject to anti-dilution adjustments generally similar to those applicable to the conversion rate of the 2023 Notes. On the same day, we also entered into warrant transactions with the Option Counterparties in which we agreed to sell the Option Counterparties warrants that are initially exercisable into 4.2 million ordinary shares and subject to adjustment upon the occurrence of certain events. The strike price of the warrants will initially be $40.86 per ordinary share, which is approximately 36.3% above the last reported sale price of the ordinary shares on January 30, 2019, as reported on the NASDAQ Global Select Market. The warrant transactions will have a dilutive effect on the ordinary shares to the extent that the market price per ordinary share, as measured under the terms of the warrant transactions, exceeds the strike price of the warrants. WMG paid approximately $30.1 million in the aggregate to the Option Counterparties for the note hedge transactions, and received approximately $21.2 million in the aggregate from the Option Counterparties for the warrants, resulting in a net cost to us of approximately $8.9 million . In connection with the above described exchange, WMG also settled a pro rata share of the 2020 Notes Conversion Derivatives, 2020 Notes Hedges, and warrants corresponding to the amount of 2020 Notes exchanged pursuant to this exchange. Increase of ABL Facility In February 2019, we amended the ABL Credit Agreement to, among other things, increase the amount of commitments under the line of credit from $150 million to $175 million and under the second tranche of the Term Loan Facility from $20 million to $35 million . As a result of the increase under the line of credit, the amount of additional commitments we are able to activate under the line of credit was reduced from $100 million to $75 million .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 30, 2018
Accounting Policies [Abstract]
Fair Value Measurement, Policy [Policy Text Block]	We account for derivatives in accordance with FASB ASC 815, which establishes accounting and reporting standards requiring that derivative instruments be recorded on the balance sheet as either an asset or liability measured at fair value. Additionally, changes in the derivatives' fair value shall be recognized currently in earnings unless specific hedge accounting criteria are met. FASB ASC Section 820, Fair Value Measurements and Disclosures requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Financial instruments with unadjusted, quoted prices listed on active market exchanges. Level 2: Financial instruments determined using prices for recently traded financial instruments with similar underlying terms as well as directly or indirectly observable inputs, such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3: Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques.
Principles of Consolidation Policy	Principles of consolidation. The accompanying consolidated financial statements include our accounts and those of our controlled subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates Policy	Use of estimates. The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. The most significant areas requiring the use of management estimates relate to revenue recognition, the determination of allowances for doubtful accounts and excess and obsolete inventories, accounting for business combinations and the evaluation of goodwill and long-lived assets, valuation of in-process research and development, product liability claims, product liability insurance recoveries and other litigation, income taxes, and share-based compensation
Discontinued Operations, Policy [Policy Text Block]	Discontinued operations. On October 21, 2016, pursuant to a binding offer letter dated as of July 8, 2016, Tornier France SAS and certain other entities related to us and Corin entered into a business sale agreement and simultaneously completed and closed the sale of our Large Joints business. Pursuant to the terms of the agreement, we sold substantially all of our assets related to our Large Joints business to Corin for approximately €29.7 million in cash, less approximately €11.1 million for net working capital adjustments. Upon closing, the parties also executed a transitional services agreement and supply agreement, among other ancillary agreements required to implement the transaction. These agreements were on arm’s length terms and were not material to our financial statements. On January 9, 2014, pursuant to an Asset Purchase Agreement, dated as of June 18, 2013 (the MicroPort Agreement), by and among us and MicroPort, we completed the divesture and sale of our business operations operating under our prior OrthoRecon operating segment (the OrthoRecon Business) to MicroPort. Pursuant to the terms of the MicroPort Agreement, the purchase price (as defined in the agreement) for the OrthoRecon Business was approximately $283 million (including a working capital adjustment), which MicroPort paid in cash. All historical operating results for the Large Joints and OrthoRecon businesses, including costs associated with corporate employees and infrastructure transferred as a part of the sales, are reflected within discontinued operations in the consolidated statements of operations. See Note 4 for further discussion of discontinued operations. Other than Note 4 , unless otherwise stated, all discussion of assets and liabilities in these Notes to the Consolidated Financial Statements reflect the assets and liabilities held and used in our continuing operations, and all discussion of revenues and expenses reflect those associated with our continuing operations.
Cash and Cash Equivalents Policy	Cash and cash equivalents. Cash and cash equivalents include all cash balances and short-term investments with original maturities of three months or less. Any such investments are readily convertible into known amounts of cash, and are so near their maturity that they present insignificant risk of changes in value because of interest rate variation.
Inventory Policy	Inventories. Our inventories are valued at the lower of cost or market on a FIFO basis. Inventory costs include material, labor costs, and manufacturing overhead. Our excess and obsolete inventory reserve is based on both the current age of kit inventory as compared to its estimated life cycle and our forecasted product demand and production requirements for other inventory items for the next 36 months. Total charges incurred to write down excess and obsolete inventory to net realizable value included in “Cost of sales” were approximately $20.9 million , $19.2 million , and $21.5 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. During the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , our excess and obsolete charges included product rationalization initiative adjustments of $4.4 million , $3.1 million , and $4.1 million , respectively.
Product Liability Policy	Product liability claims and related insurance recoveries and other litigation. We are involved in legal proceedings involving product liability claims as well as contract, patent protection, and other matters. See Note 16 for additional information regarding product liability claims, product liability insurance recoveries, and other litigation. We make provisions for claims specifically identified for which we believe the likelihood of an unfavorable outcome is probable and the amount of loss can be estimated. For unresolved contingencies with potentially material exposure that are deemed reasonably possible, we evaluate whether a potential loss or range of loss can be reasonably estimated. Our evaluation of these matters is the result of a comprehensive process designed to ensure that recognition of a loss or disclosure of these contingencies is made in a timely manner. In determining whether a loss should be accrued or a loss contingency disclosed, we evaluate a number of factors including: the procedural status of each lawsuit; any opportunities for dismissal of the lawsuit before trial; the amount of time remaining before trial date; the status of discovery; the status of settlement; arbitration or mediation proceedings; and management’s estimate of the likelihood of success prior to or at trial. The estimates used to establish a range of loss and the amounts to accrue are based on previous settlement experience, consultation with legal counsel, and management’s settlement strategies. If the estimate of a probable loss is in a range and no amount within the range is more likely, we accrue the minimum amount of the range. We recognize legal fees as an expense in the period incurred. These expenses are reflected in either continuing or discontinued operations depending on the product associated with the claim. We record insurance recoveries from product liability insurance that is in force when they are realized or realizable, when we believe it is probable that the insurance carrier will settle the claim.
Property, Plant and Equipment Policy	Property, plant and equipment. Our property, plant and equipment is stated at cost. Depreciation, which includes amortization of assets under capital lease, is generally provided on a straight-line basis over the estimated useful lives generally based on the following categories: Land improvements 15 to 25 years Buildings and building improvements 10 to 40 years Machinery and equipment 3 to 14 years Furniture, fixtures and office equipment 3 to 14 years Surgical instruments 6 years Expenditures for major renewals and betterments, including leasehold improvements, that extend the useful life of the assets are capitalized and depreciated over the remaining life of the asset or lease term, if shorter. Maintenance and repair costs are charged to expense as incurred. Upon sale or retirement, the asset cost and related accumulated depreciation are eliminated from the respective accounts and any resulting gain or loss is included in income.
Intangible Assets and Goodwill Policy	Intangible assets and goodwill. Goodwill is recognized for the excess of the purchase price over the fair value of net assets of businesses acquired. FASB ASC 350-30-35-18 requires companies to evaluate for impairment intangible assets not subject to amortization, such as our IPRD assets, if events or changes in circumstances indicate than an asset might be impaired. Further, FASB ASC 350-20-35-30 requires companies to evaluate goodwill and intangibles not subject to amortization for impairment between annual impairment tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Unless circumstances otherwise dictate, the annual impairment test is performed on October 1 each year. See Note 8 for discussion of our 2018 goodwill impairment analysis. Our intangible assets with estimable useful lives are amortized on a straight-line basis over their respective estimated useful lives to their estimated residual values. This method of amortization approximates the expected future cash flow generated from their use. Finite-lived intangibles are reviewed for impairment in accordance with FASB ASC Section 360, Property, Plant and Equipment (FASB ASC 360). The weighted average amortization periods for our intangible assets are as follows: Completed technology 10 years Distribution channels 10 years Trademarks 5 years Licenses 11 years Customer relationships 17 years Non-compete agreements 4 years Other intangible assets 3 years
Valuation of Long-Lived Assets Policy	Valuation of long-lived assets. Management periodically evaluates carrying values of long-lived assets, including property, plant and equipment and finite-lived intangible assets, when events and circumstances indicate that these assets may have been impaired. We account for the impairment of long-lived assets in accordance with FASB ASC 360 . Accordingly, we evaluate impairment of our long-lived assets based upon an analysis of estimated undiscounted future cash flows. If it is determined that a change is required in the useful life of an asset, future depreciation and amortization is adjusted accordingly. Alternatively, should we determine that an asset is impaired, an adjustment would be charged to income based on the difference between the asset’s fair market value and the asset's carrying value.
Allowance for Doubtful Accounts Policy	Allowances for doubtful accounts. We experience credit losses on our accounts receivable; and accordingly, we must make estimates related to the ultimate collection of our accounts receivable. Specifically, we analyze our accounts receivable, historical bad debt experience, customer concentrations, customer creditworthiness, and current economic trends when evaluating the adequacy of our allowance for doubtful accounts. The majority of our accounts receivable are from hospitals and surgery centers. Our collection history has been favorable with minimal bad debts from these customers. We write-off accounts receivable when we determine that the accounts receivable are uncollectible, typically upon customer bankruptcy or the customer’s non-response to repeated collection efforts. Our allowance for doubtful accounts totaled $3.0 million and $ 4.3 million at December 30, 2018 and December 31, 2017 , respectively.
Concentration of Credit Risk Policy	Concentration of credit risk. Financial instruments that potentially subject us to concentrations of credit risk consist principally of accounts receivable. Management attempts to minimize credit risk by reviewing customers’ credit history before extending credit and by monitoring credit exposure on a regular basis. Collateral or other security is generally not required for accounts receivable.
Concentrations of Supply of Raw Materials [Policy Text Block]	Concentrations of supply of raw material . We rely on a limited number of suppliers for the components used in our products. For certain human biologic products, such as Allomatrix ® , we depend on one supplier of demineralized bone matrix and cancellous bone matrix. We rely on two suppliers for our GRAFTJACKET ® family of soft tissue repair and graft containment products. Additionally, we have other soft tissue repair products for which we rely on one supplier, which include our ACTISHIELD™ and ACTISHIELD™ CF Amniotic Barrier Membranes and VIAFLOW™ and VIAFLOW™ C Flowable Placental Tissue Matrices. We maintain adequate stock from these suppliers in order to meet market demand .
Income Tax Policy	Income taxes. Income taxes are accounted for pursuant to the provisions of FASB ASC Section 740, Income Taxes (FASB ASC 740). Our effective tax rate is based on income by tax jurisdiction, statutory rates, and tax saving initiatives available to us in the various jurisdictions in which we operate. Significant judgment is required in determining our effective tax rate and evaluating our tax positions. This process includes assessing temporary differences resulting from differing recognition of items for income tax and financial accounting purposes. These differences result in deferred tax assets and liabilities, which are included within our consolidated balance sheet. The measurement of deferred tax assets is reduced by a valuation allowance if, based upon available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. See Note 11 for further discussion of our consolidated deferred tax assets and liabilities, and the associated valuation allowance. We provide for unrecognized tax benefits based upon our assessment of whether a tax position is “more-likely-than-not” to be sustained upon examination by the tax authorities. If a tax position meets the more-likely-than-not standard, then the related tax benefit is measured based on a cumulative probability analysis of the amount that is more-likely-than-not to be realized upon ultimate settlement or disposition of the underlying tax position. In December 2017, the United States enacted new legislation under the 2017 Tax Act. We recognized the income tax effects of the 2017 Tax Act in our 2017 financial statements in accordance with Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which allowed us to record provisional amounts under a one-year measurement period. We finalized our accounting for the provisions of the 2017 Tax Act in the fourth-quarter 2018 with no material impact on our financial statements. During 2018, we have adopted ASU 2018-02, Reclassification of Certain Income Tax Effects from Accumulated Other Comprehensive Income , issued in February 2018, allowing the reclassification of income tax effects of the 2017 Tax Act, referred to as “stranded tax effects” by FASB, from accumulated other comprehensive income (AOCI) to retained earnings. This adoption did not have a material impact on our financial statements.
Other Taxes Policy	Other taxes. Taxes assessed by a governmental authority that are imposed concurrent with our revenue transactions with customers are presented on a net basis in our consolidated statements of operations.
Revenue Recognition Policy	Revenue recognition. Our revenues are primarily generated through two types of customers, hospitals and surgery centers and stocking distributors, with the majority of our revenue derived from sales to hospitals and surgery centers. Our products are sold through a network of employee and independent sales representatives in the United States and by a combination of employee sales representatives, independent sales representatives, and stocking distributors outside the United States. We record revenues from sales to hospitals and surgery centers upon transfer of control of promised products in an amount that reflects the consideration we expect to receive in exchange for those products, which is generally when the product is surgically implanted in a patient. We record revenues from sales to our stocking distributors at a point in time upon transfer of control of promised products to the distributor. Our stocking distributors, who sell the products to their customers, take control of the products and assume all risks of ownership upon transfer. Our stocking distributors are obligated to pay us within specified terms regardless of when, if ever, they sell the products. In general, our stocking distributors do not have any rights of return or exchange; however, in limited situations, we have repurchase agreements with certain stocking distributors. Those certain agreements require us to repurchase a specified percentage of the inventory purchased by the distributor within a specified period of time prior to the expiration of the contract. During those specified periods, we defer the applicable percentage of the sales. An insignificant amount of sales related to these types of agreements was deferred and not yet recognized as revenue as of December 30, 2018 and December 31, 2017 .
Shipping and Handling Costs Policy	Shipping and handling costs . We incur shipping and handling costs associated with the shipment of goods to customers, independent distributors, and our subsidiaries. Amounts billed to customers for shipping and handling of products are included in net sales. Costs incurred related to shipping and handling of products to customers are included in selling, general and administrative expenses. Shipping and handling costs within selling, general and administrative expenses totaled $52.0 million , $49.4 million and $44.0 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. These amounts include instrument depreciation which totaled $28.4 million , $27.1 million , and $26.1 million for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively. All other shipping and handling costs are included in cost of sales.
Research and Development Policy	Research and development costs. Research and development costs are charged to expense as incurred.
Foreign Currency Translations Policy	Foreign currency translation. The financial statements of our subsidiaries whose functional currency is the local currency are translated into U.S. dollars using the exchange rate at the balance sheet date for assets and liabilities and the weighted average exchange rate for the applicable period for revenues, expenses, gains, and losses. Translation adjustments are recorded as a separate component of comprehensive loss in shareholders’ equity. Gains and losses resulting from transactions denominated in a currency other than the local functional currency are included in “Other expense (income), net” in our consolidated statements of operations.
Comprehensive Income Policy	Comprehensive income. Comprehensive income is defined as the change in equity during a period related to transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners. The difference between our net loss and our comprehensive loss is attributable to foreign currency translation.
Stock-based Compensation Policy	Share-based compensation. We account for share-based compensation in accordance with FASB ASC Section 718, Compensation — Stock Compensation (FASB ASC 718). Under the fair value recognition provisions of FASB ASC 718, share-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense on a straight-line basis over the requisite service period, which is the vesting period. The determination of the fair value of share-based payment awards, such as options, on the date of grant using an option-pricing model is affected by our stock price, as well as assumptions regarding a number of complex and subjective variables, which include the expected life of the award, the expected stock price volatility over the expected life of the awards, expected dividend yield, and risk-free interest rate. The determination of the fair value of performance-based share-based payment awards, such as performance share units, is based on the estimated achievement of the established performance criteria on the date of grant and updated at the end of each reporting period until the performance period ends. Share-based compensation expense is only recognized for performance share units that we expect to vest, which we estimate based upon an assessment of the probability that the performance criteria will be achieved. We recorded share-based compensation expense of $26.1 million , $19.4 million , and $14.4 million during the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 , respectively, within our results of continuing operations. See Note 14 for further information regarding our share-based compensation assumptions and expenses.
Derivative Instruments Policy	Derivative instruments. We account for derivative instruments and hedging activities under FASB ASC Section 815, Derivatives and Hedging (FASB ASC 815). Accordingly, all of our derivative instruments are recorded in the accompanying consolidated balance sheets as either an asset or liability and measured at fair value. The changes in the derivative’s fair value are recognized currently in earnings unless specific hedge accounting criteria are met. During 2016 and 2017, we employed a derivative program using foreign currency forward contracts to mitigate the risk of currency fluctuations on our intercompany receivable and payable balances that were denominated in foreign currencies. These forward contracts were expected to offset the transactional gains and losses on the related intercompany balances. These forward contracts were not designated as hedging instruments under FASB ASC 815. Accordingly, the changes in the fair value and the settlement of the contracts were recognized in the period incurred in the accompanying consolidated statements of operations. We discontinued our foreign currency forward contracts derivative program in 2018. We recorded a net loss of approximately $4.6 million and $0.8 million on our foreign currency contracts for the fiscal years ended December 31, 2017 and December 25, 2016 , respectively. These losses substantially offset translation gains recorded on our intercompany receivable and payable balances, and are also included in “Other (income) expense, net.” On February 13, 2015, May 20, 2016, and June 28, 2018, we issued the 2020 Notes, 2021 Notes, and 2023 Notes, respectively, as defined and described in Note 9 . The 2020 Notes Conversion Derivatives, 2021 Notes Conversion Derivatives, and 2023 Notes Conversion Derivatives each as defined and described in Note 6 , require bifurcation from the 2020 Notes, 2021 Notes, and 2023 Notes in accordance with ASC Topic 815, and are accounted for as derivative liabilities. We also entered into 2020, 2021, and 2023 Notes Hedges, as defined and described in Note 6 , in connection with the issuance of the 2020, 2021, and 2023 Notes. The 2020, 2021, and 2023 Notes Hedges, which are cash-settled, are intended to reduce our exposure to potential cash payments that we are required to make upon conversion of the 2020, 2021, and 2023 Notes in excess of the principal amount of converted notes if our ordinary share price exceeds the conversion price. The 2020, 2021, and 2023 Notes Hedges are accounted for as derivative assets in accordance with ASC Topic 815.

Earnings per share (Policies)

Earnings per share (Policies)	12 Months Ended
	Dec. 30, 2018
Earnings Per Share Policies [Abstract]
Earnings Per Share [Abstract]	FASB ASC Topic 260, Earnings Per Share, requires the presentation of basic and diluted earnings per share. Basic earnings per share is calculated based on the weighted-average number of ordinary shares outstanding during the period. Diluted earnings per share is calculated to include any dilutive effect of our ordinary share equivalents. For the fiscal years ended December 30, 2018 and December 31, 2017 , our ordinary share equivalents consisted of stock options, restricted stock units, performance share units, and warrants. For the fiscal year ended December 25, 2016 , our ordinary share equivalents consisted of stock options, restricted stock units, and warrants. The dilutive effect of the stock options, restricted stock units, performance share units, and warrants is calculated using the treasury-stock method.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 30, 2018
Accounting Policies [Abstract]
Weighted Average Amortization Periods of Intangible Assets [Table Text Block]	The weighted average amortization periods for our intangible assets are as follows: Completed technology 10 years Distribution channels 10 years Trademarks 5 years Licenses 11 years Customer relationships 17 years Non-compete agreements 4 years Other intangible assets 3 years
Schedule of Estimated Useful Lives of Property, Plant and Equipment	Depreciation, which includes amortization of assets under capital lease, is generally provided on a straight-line basis over the estimated useful lives generally based on the following categories: Land improvements 15 to 25 years Buildings and building improvements 10 to 40 years Machinery and equipment 3 to 14 years Furniture, fixtures and office equipment 3 to 14 years Surgical instruments 6 years
Supplemental Cash Flow Information	Supplemental cash flow information. Cash paid for interest and income taxes was as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Interest $ 30,552 $ 24,641 $ 18,678 Income taxes $ 6,254 $ 7,359 $ 4,334

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 30, 2018
IMASCAP SAS [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following presents the allocation of the purchase consideration to the assets acquired and liabilities assumed on December 14, 2017 (in thousands): Cash and cash equivalents $ 2,559 Accounts receivable 102 Other current assets 925 Property, plant and equipment 20 Intangible assets 10,865 Total assets acquired 14,471 Current liabilities (2,173 ) Long-term debt (886 ) Deferred income taxes (2,343 ) Total liabilities assumed (5,402 ) Net assets acquired $ 9,069 Goodwill 71,064 Total purchase consideration $ 80,133
Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma combined financial information summarizes the results of operations for the periods indicated as if the Cartiva acquisition had been completed as of December 26, 2016, the beginning of Wright's fiscal year 2017. Pro forma information reflects adjustments that are expected to have a continuing impact on our results of operations and are directly attributable to the acquisition. The unaudited pro forma results include adjustments to reflect the amortization of the inventory step-up and the incremental intangible asset amortization to be incurred based on the preliminary values of each identifiable intangible asset. The pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisition had occurred as of December 26, 2016 or that may be obtained in the future, and do not reflect future synergies, integration costs, or other such costs or savings. Year ended December 30, 2018 Year ended December 31, 2017 Net sales $ 861,475 $ 769,111 Net loss from continuing operations (179,800 ) (68,722 )
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following presents the preliminary allocation of the purchase consideration to the assets acquired and liabilities assumed on October 10, 2018 (in thousands): Cash and cash equivalents $ 309 Accounts receivable 4,352 Inventories 2,686 Other current assets 486 Property, plant and equipment 1,446 Intangible assets 81,000 Total assets acquired 90,279 Current liabilities (4,226 ) Deferred income taxes (3,622 ) Total liabilities assumed (7,848 ) Net assets acquired $ 82,431 Goodwill 351,445 Total preliminary purchase consideration $ 433,876

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 30, 2018
Large Joints Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	The following table summarizes the results of discontinued operations for the Large Joints business (in thousands) for the fiscal year ended December 25, 2016 : Fiscal year ended December 25, 2016 Net sales $ 35,318 Cost of sales 20,244 Selling, general and administrative 18,808 Loss from discontinued operations before income taxes (3,734 ) Impairment loss on assets held for sale, before income taxes 21,342 Total loss from discontinued operations before income taxes (25,076 ) Benefit for income taxes (5,615 ) Total loss from discontinued operations, net of tax $ (19,461 )
OrthoRecon Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	The following table summarizes the results of discontinued operations for the OrthoRecon business (in thousands, except per share data): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Net sales $ — $ — $ — Selling, general and administrative (746 ) 135,235 247,978 Income (loss) from discontinued operations before income taxes 746 (135,235 ) (247,978 ) Provision (benefit) for income taxes 221 (1,707 ) — Total income (loss) from discontinued operations, net of tax $ 525 $ (133,528 ) $ (247,978 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 30, 2018
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): December 30, 2018 December 31, 2017 Raw materials $ 9,612 $ 10,816 Work-in-process 26,839 28,581 Finished goods 144,239 128,747 $ 180,690 $ 168,144

Derivatives and Fair Value of_2

Derivatives and Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 30, 2018
Derivatives, Fair Value [Line Items]
Fair Value Financial Instruments [Table Text Block]	The following tables summarize the valuation of our financial instruments (in thousands): Total Quoted prices in active markets (Level 1) Prices with other observable inputs (Level 2) Prices with unobservable inputs (Level 3) At December 30, 2018 Assets Cash and cash equivalents $ 191,351 $ 191,351 $ — $ — 2020 Notes Hedges 17,822 — — 17,822 2021 Notes Hedges 188,301 — — 188,301 2023 Notes Hedges 115,923 — — 115,923 Total $ 513,397 $ 191,351 $ — $ 322,046 Liabilities 2020 Notes Conversion Derivative $ 17,386 $ — $ — $ 17,386 2021 Notes Conversion Derivative 187,539 — — 187,539 2023 Notes Conversion Derivative 116,833 — — 116,833 Contingent consideration 19,248 — — 19,248 Contingent consideration (CVRs) 420 420 — — Total $ 341,426 $ 420 $ — $ 341,006 Total Quoted prices in active markets (Level 1) Prices with other observable inputs (Level 2) Prices with unobservable inputs (Level 3) At December 31, 2017 Assets Cash and cash equivalents $ 167,740 $ 167,740 $ — $ — 2020 Notes Hedges 45,033 — — 45,033 2021 Notes Hedges 127,063 — — 127,063 Total $ 339,836 $ 167,740 $ — $ 172,096 Liabilities 2020 Notes Conversion Derivative $ 44,132 $ — $ — $ 44,132 2021 Notes Conversion Derivative 126,148 — — 126,148 Contingent consideration 19,188 — — 19,188 Contingent consideration (CVRs) 42,325 42,325 — — Total $ 231,793 $ 42,325 $ — $ 189,468 The following is a roll forward of our assets and liabilities measured at fair value (in thousands) on a recurring basis using unobservable inputs (Level 3) (in thousands): Balance at December 31, 2017 Additions Transfers into Level 3 Gain/(loss) included in earnings Settlements Currency Balance at December 30, 2018 2020 Notes Hedges 45,033 — — 7,342 (34,553 ) — 17,822 2020 Notes Conversion Derivative (44,132 ) — — (28,897 ) 55,643 — (17,386 ) 2020 Warrants Derivative — (27,308 ) — 3,336 23,972 — — 2021 Notes Hedges 127,063 — — 61,238 — — 188,301 2021 Notes Conversion Derivative (126,148 ) — — (61,391 ) — — (187,539 ) 2023 Notes Hedges — 141,278 — (25,355 ) — — 115,923 2023 Notes Conversion Derivative — (124,625 ) — 7,792 — — (116,833 ) Contingent consideration (19,188 ) — — (1,789 ) 919 810 (19,248 )
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2023 Notes Hedges and 2023 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 2023 Notes Hedges Other assets $ 115,923 2023 Notes Conversion Derivative Other liabilities $ 116,833
Derivative Instruments, Gain (Loss) [Table Text Block]	The following table summarizes the net (loss) gain on changes in fair value (in thousands) related to the 2023 Notes Hedges and 2023 Notes Conversion Derivative: Fiscal year ended December 30, 2018 2023 Notes Hedges $ (25,355 ) 2023 Notes Conversion Derivative 7,792 Net loss on changes in fair value $ (17,563 )
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block]	The following assumptions were used in the fair market valuations as of December 30, 2018 : 2020 Notes Conversion Derivative 2020 Notes Hedge 2021 Notes Conversion Derivative 2021 Notes 2023 Notes Conversion Derivative 2023 Notes Hedge Black Stock Volatility 1 34.48% 34.48% 42.2% 42.2% 31.9% 31.9% Credit Spread for Wright 2 4.67% N/A 4.50% N/A 3.72% N/A Credit Spread for Deutsche Bank AG 3 N/A 1.38% N/A N/A N/A N/A Credit Spread for Wells Fargo Securities, LLC 3 N/A 0.25% N/A N/A N/A N/A Credit Spread for JPMorgan Chase Bank 3 N/A 0.3% N/A 0.45% N/A 0.56% Credit Spread for Bank of America 3 N/A N/A N/A 0.46% N/A 0.59% 1 Volatility selected based on historical and implied volatility of ordinary shares of Wright Medical Group N.V. 2 Credit spread implied from traded price. 3 Credit spread of each bank is estimated using CDS curves. Source: Bloomberg.
2021 Derivatives [Member]
Derivatives, Fair Value [Line Items]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2021 Notes Hedges and 2021 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 December 31, 2017 2021 Notes Hedges Other assets $ 188,301 $ 127,063 2021 Notes Conversion Derivative Other liabilities $ 187,539 $ 126,148
Derivative Instruments, Gain (Loss) [Table Text Block]	The following table summarizes the net gain (loss) on changes in fair value (in thousands) related to the 2021 Notes Hedges and 2021 Notes Conversion Derivative: Fiscal year ended December 30, 2018 December 31, 2017 2021 Notes Hedges $ 61,238 $ (32,032 ) 2021 Notes Conversion Derivative (61,391 ) 35,453 Net (loss)/gain on changes in fair value $ (153 ) $ 3,421
2020 Derivatives [Member]
Derivatives, Fair Value [Line Items]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table summarizes the fair value and the presentation in our consolidated balance sheets (in thousands) of the 2020 Notes Hedges and 2020 Notes Conversion Derivative: Location on consolidated balance sheet December 30, 2018 Location on consolidated balance sheet December 31, 2017 2020 Notes Hedges Other current assets $ 17,822 Other assets $ 45,033 2020 Notes Conversion Derivative Accrued expenses and other current liabilities $ 17,386 Other liabilities $ 44,132
Derivative Instruments, Gain (Loss) [Table Text Block]	The following table summarizes the net gain (loss) on changes in fair value (in thousands) related to the 2020 Notes Hedges, 2020 Warrants Derivative and 2020 Notes Conversion Derivative: Fiscal year ended December 30, 2018 December 31, 2017 2020 Notes Hedges $ 7,342 $ (32,199 ) 2020 Warrants Derivative 3,336 — 2020 Notes Conversion Derivative (28,897 ) 33,626 Net (loss)/gain on changes in fair value $ (18,219 ) $ 1,427

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 30, 2018
Property, Plant and Equipment, Net [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment, net consists of the following (in thousands): December 30, 2018 December 31, 2017 Land and land improvements $ 2,127 $ 2,163 Buildings 43,087 41,537 Machinery and equipment 82,445 60,859 Furniture, fixtures and office equipment 161,614 142,299 Construction in progress 14,113 14,403 Surgical instruments 230,980 187,660 534,366 448,921 Less: Accumulated depreciation (309,437 ) (236,542 ) $ 224,929 $ 212,379
Property, Plant and Equipment Recorded Under Capital Leases	The components of property, plant and equipment recorded under capital leases consist of the following (in thousands): December 30, 2018 December 31, 2017 Buildings $ 12,017 $ 15,530 Machinery and equipment 24,331 12,478 Furniture, fixtures and office equipment 559 960 36,907 28,968 Less: Accumulated depreciation (11,906 ) (7,749 ) $ 25,001 $ 21,219

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the Carrying Amount of Goodwill Table	Changes in the carrying amount of goodwill occurring during the fiscal years ended December 31, 2017 and December 30, 2018 , are as follows (in thousands): U.S. Lower Extremities U.S. Upper Extremities International Extremities Total Goodwill at December 25, 2016 $ 218,525 $ 558,669 $ 73,848 $ 851,042 Goodwill associated with IMASCAP acquisition — 71,981 — 71,981 Foreign currency translation — — 10,639 10,639 Goodwill at December 31, 2017 $ 218,525 $ 630,650 $ 84,487 $ 933,662 Goodwill associated with Cartiva acquisition 351,445 — — 351,445 Goodwill adjustment associated with IMASCAP acquisition — (917 ) — (917 ) Foreign currency translation — (1,883 ) (13,353 ) (15,236 ) Goodwill at December 30, 2018 $ 569,970 $ 627,850 $ 71,134 $ 1,268,954
Components of Identifiable Assets Table	The components of our identifiable intangible assets, net are as follows (in thousands):

Long-Term Debt and Capital Le_2

Long-Term Debt and Capital Lease Obligations (Tables)	12 Months Ended
	Dec. 30, 2018
Debt Instrument [Line Items]
Schedule of Long-term Debt Instruments	Debt and capital lease obligations consist of the following (in thousands): December 30, 2018 December 31, 2017 Capital lease obligations $ 25,539 $ 20,401 2023 Notes 548,076 — 2021 Notes 321,286 300,051 2020 Notes 1 173,533 513,014 Term Loan Facility 18,979 — Asset-based line of credit 17,761 53,645 Other debt 9,953 8,003 1,115,127 895,114 Less: current portion 1 (201,686 ) (58,906 ) $ 913,441 $ 836,208
Schedule of Maturities of Long-term Obligations	Aggregate annual maturities of our current and long-term obligations at December 30, 2018 , excluding capital lease obligations and the ABL Facility, are as follows (in thousands): 2019 $ 190,597 2020 2,125 2021 416,463 2022 935 2023 675,042 Thereafter 1,380 $ 1,286,542
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]	At December 30, 2018 , future minimum lease payments under capital lease obligations, together with the present value of the net minimum lease payments, are as follows (in thousands): 2019 $ 7,369 2020 6,106 2021 4,545 2022 3,553 2023 2,430 Thereafter 4,682 Total minimum payments 28,685 Less amount representing interest (3,146 ) Present value of minimum lease payments 25,539 Current portion (6,384 ) Long-term portion $ 19,155
2023 Convertible Debt [Member]
Debt Instrument [Line Items]
Components Of Convertible Debt	The components of the 2023 Notes were as follows (in thousands): December 30, 2018 Principal amount of 2023 Notes $ 675,000 Unamortized debt discount (114,554 ) Unamortized debt issuance costs (12,370 ) Net carrying amount of 2023 Notes $ 548,076
2021 Convertible Debt [Member]
Debt Instrument [Line Items]
Components Of Convertible Debt	The components of the 2021 Notes were as follows (in thousands): December 30, 2018 December 31, 2017 Principal amount of 2021 Notes $ 395,000 $ 395,000 Unamortized debt discount (69,382 ) (89,332 ) Unamortized debt issuance costs (4,332 ) (5,617 ) Net carrying amount of 2021 Notes $ 321,286 $ 300,051
2020 convertibledebt [Member]
Debt Instrument [Line Items]
Components Of Convertible Debt	The components of the 2020 Notes were as follows (in thousands): December 30, 2018 December 31, 2017 Principal amount of 2020 Notes $ 186,589 $ 587,500 Unamortized debt discount (11,642 ) (66,418 ) Unamortized debt issuance costs (1,414 ) (8,068 ) Net carrying amount of 2020 Notes $ 173,533 $ 513,014

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 30, 2018
Accumulated Other Comprehensive Income [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Changes in AOCI for the fiscal years ended December 25, 2016 , December 31, 2017 , and December 30, 2018 were as follows (in thousands): Currency translation adjustment Balance December 27, 2015 $ (10,484 ) Other comprehensive loss (8,977 ) Balance December 25, 2016 $ (19,461 ) Other comprehensive income 41,751 Balance December 31, 2017 $ 22,290 Other comprehensive loss (30,373 ) Balance December 30, 2018 $ (8,083 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 30, 2018
Income Tax Disclosure [Abstract]
Income Before Income Taxes	The components of our loss from continuing operations before income taxes are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 U.S. $ (144,987 ) $ (56,808 ) $ (140,190 ) Foreign (24,853 ) (43,097 ) (38,150 ) Loss from continuing operations before income taxes $ (169,840 ) $ (99,905 ) $ (178,340 )
Components of Provision for Income Taxes	The components of our benefit for income taxes are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Current (benefit) provision: U.S.: Federal $ 449 $ (23,781 ) $ (1,971 ) State 251 390 (281 ) Foreign 3,307 2,214 3,860 Total current (benefit) provision 4,007 (21,177 ) 1,608 Deferred (benefit) provision: U.S.: Federal (2,841 ) (5,098 ) 1,244 State (663 ) (93 ) 142 Foreign (1,039 ) (8,600 ) (16,400 ) Total deferred benefit (4,543 ) (13,791 ) (15,014 ) Total benefit for income taxes $ (536 ) $ (34,968 ) $ (13,406 )
Reconciliation of the Statutory U.S. Federal Income Tax Rate to Effective Income Tax Rate	A reconciliation of the statutory U.S. federal income tax rate to our effective income tax rate for continuing operations is as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Income tax benefit at statutory rate 21.0 % 35.0 % 35.0 % State income taxes 3.8 % 1.5 % 2.9 % Change in valuation allowance (22.9 )% (3.5 )% (32.6 )% CVR fair market value adjustment — % (1.9 )% (1.7 )% Foreign income tax rate differential (0.6 )% (6.1 )% 3.3 % Changes in tax reserves 0.4 % 2.9 % 0.8 % Effects of U.S. tax reform — % 6.5 % — % Foreign rate changes — % 1.7 % — % Other, net (1.4 )% (1.1 )% (0.2 )% Total 0.3 % 35.0 % 7.5 %
Significant Components of Deferred Income Taxes	The significant components of our deferred income taxes as of December 30, 2018 and December 31, 2017 are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 Deferred tax assets: Net operating loss carryforwards $ 330,589 $ 283,708 General business credit carryforwards 14,598 12,993 Reserves and allowances 56,675 90,246 Deferred interest 27,322 — Share-based compensation expense 14,934 13,679 Convertible debt notes and conversion options 38,368 10,747 Other 3,616 1,642 Valuation allowance (400,171 ) (366,825 ) Total deferred tax assets 85,931 46,190 Deferred tax liabilities: Depreciation 5,095 6,383 Intangible assets 58,221 42,862 Convertible notes bond hedges 34,653 11,668 Other 166 120 Total deferred tax liabilities 98,135 61,033 Net deferred tax liabilities $ (12,204 ) $ (14,843 )
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 Balance at beginning of fiscal year $ 6,025 $ 8,095 Additions from acquisitions 109 — Additions for tax positions related to current year 385 215 Additions for tax positions of prior years 718 20 Reductions for tax positions of prior years (490 ) (3,174 ) Settlements (1,983 ) — Foreign currency translation (154 ) 869 Balance at end of fiscal year $ 4,610 $ 6,025

Other Balance Sheet Informati_2

Other Balance Sheet Information (Tables)	12 Months Ended
	Dec. 30, 2018
Other Long-Term Liabilities [Abstract]
Schedule of Accrued Expenses and Other Liabilities [Table Text Block]	Accrued expenses and other current liabilities consist of the following (in thousands): December 30, 2018 December 31, 2017 Employee bonuses $ 28,953 $ 12,803 Other employee benefits 22,841 22,401 Royalties 12,330 12,563 Taxes other than income 7,897 8,933 Notes Conversion Derivatives ( Note 6 ) 17,386 — Commissions 19,356 19,330 Professional and legal fees 10,848 12,388 Contingent consideration ( Note 6 ) 3,427 1,168 Product liability and other legal accruals ( Note 16 ) 66,918 151,027 CVRs ( Note 6 ) 420 42,044 Other 26,705 31,901 $ 217,081 $ 314,558
Other Long-Term Liabilities	Other long-term liabilities consist of the following (in thousands): December 30, 2018 December 31, 2017 Product liability reserves ( Note 16 ) $ 30,755 $ 60,711 Notes Conversion Derivatives ( Note 6 ) 304,372 170,280 Contingent consideration ( Note 6 ) 15,821 18,301 Other 17,281 23,453 $ 368,229 $ 272,745

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 30, 2018
Earnings Per Share [Abstract]
Weighted Average Number of Shares Outstanding for Basic and Diluted Earnings Per Share	The weighted-average number of ordinary shares outstanding for basic and diluted loss per share purposes is as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Weighted-average number of ordinary shares outstanding — basic and diluted 112,592 104,531 102,968

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Amounts Recognized Within the Consolidated Financial Statements	Amounts recognized in the consolidated financial statements with respect to share-based compensation are as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Total cost of share-based arrangements $ 26,039 $ 19,485 $ 14,406 Amounts capitalized into inventory (507 ) (669 ) (416 ) Amortization of capitalized amounts 588 577 426 Impact to net loss $ 26,120 $ 19,393 $ 14,416 Impact to basic and diluted loss per share $ 0.23 $ 0.19 $ 0.14 Weighted-average number of shares outstanding - basic and diluted 112,592 104,531 102,968
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	The compensation costs related to share-based awards were as follows: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Stock options $ 11,177 $ 8,988 $ 5,844 Restricted stock units 11,514 9,373 8,416 Performance share units 2,538 441 — Employee stock purchase plan 810 683 146 Total compensation cost for share-based awards $ 26,039 $ 19,485 $ 14,406
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Option Valuation Assumptions	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option valuation model using the following assumptions: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Risk-free interest rate 2.6% - 2.9% 1.9% - 2.0% 1.1% - 1.4% Expected option life 7 years 6 years 6 years Expected price volatility 32% 33% 34%
Schedule of Stock Option Activity	A summary of our stock option activity during 2018 is as follows: Shares (000’s) Weighted-average exercise price Weighted-average remaining contractual life Aggregate intrinsic value* ($000’s) Outstanding at December 31, 2017 9,114 $ 22.73 Granted 1,464 24.14 Exercised (750) 21.18 Forfeited or expired (625) 25.51 Outstanding at December 30, 2018 9,203 $ 22.89 6.52 $ 36,809 Exercisable at December 30, 2018 6,086 $ 22.30 5.46 $ 28,127
Schedule of Stock Options Outstanding and Exercisable by Exercise Price Range	A summary of our stock options outstanding and exercisable at December 30, 2018 is as follows (shares in thousands): Options outstanding Options exercisable Range of exercise prices Number outstanding Weighted-average remaining Weighted-average exercise Number exercisable Weighted-average exercise $2.00 — $20.00 1,078 4.02 $ 17.66 976 $ 17.48 $20.01 — $21.00 2,276 6.32 20.64 1,835 20.64 $21.01 — $25.00 3,753 7.16 22.85 1,945 22.21 $25.01 — $32.00 2,096 6.87 28.10 1,330 28.27 9,203 6.52 $ 22.89 6,086 $ 22.30
Nonvested Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Other Share-based Compensation, Activity	A summary of our RSU activity during 2018 is as follows: Shares (000’s) Weighted-average grant-date fair value Aggregate intrinsic value* ($000’s) Unvested at December 31, 2017 1,280 $ 23.45 Granted 607 24.05 Vested (460 ) 22.89 Forfeited (105 ) 23.63 Unvested at December 30, 2018 1,322 $ 23.90 $ 35,052
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Other Share-based Compensation, Activity	A summary of our PSU activity during 2018 is as follows: Shares (000’s) Weighted-average grant-date fair value Aggregate intrinsic value* ($000’s) Unvested at December 31, 2017 108 $ 27.86 Granted 129 24.49 Vested — — Forfeited (4 ) 27.86 Unvested at December 30, 2018 233 $ 26.00 $ 6,176
Inducement Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Stock Option Activity	A summary of our non-plan inducement stock option activity during 2018 is as follows: Shares (000’s) Weighted-average exercise price Weighted-average remaining contractual life Aggregate intrinsic value* ($000’s) Outstanding at December 31, 2017 875 $ 16.50 Granted — — Exercised (182 ) 19.71 Forfeited or expired — — Outstanding at December 30, 2018 693 $ 15.66 2.74 $ 7,522 Exercisable at December 30, 2018 693 $ 15.66 2.74 $ 7,522
Schedule of Stock Options Outstanding and Exercisable by Exercise Price Range	A summary of our non-plan inducement stock options outstanding and exercisable at December 30, 2018 is as follows (shares in thousands): Options outstanding Options exercisable Range of exercise prices Number outstanding Weighted-average remaining Weighted-average exercise Number exercisable Weighted-average exercise $15.00 — $18.00 693 2.74 $ 15.66 693 $ 15.66
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Employee Stock Purchase Plan, Valuation Assumptions	In applying the Black-Scholes methodology to purchase rights granted under the ESPP, we used the following assumptions: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 Risk-free interest rate 2.3% - 2.8% 1.3% - 1.9% 1.2% - 1.3% Expected life 6 months 6 months 3 months Expected price volatility 31% 24% 33%

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Payments Under Non-Cancelable Operating Leases	Future minimum payments, by year and in the aggregate, under non-cancelable operating leases with initial or remaining lease terms of one year or more, are as follows at December 30, 2018 (in thousands): 2019 $ 9,606 2020 7,498 2021 6,019 2022 4,433 2023 2,678 Thereafter 10,998 $ 41,232
Long-term Purchase Commitment [Table Text Block]	Purchase Obligations We have entered into certain supply agreements for our products which include minimum purchase obligations. As of December 30, 2018, we have minimum purchase obligations of $1.9 million , $1.3 million , $1.3 million for 2019, 2020, and 2021, respectively. In November 2018, we entered into a lease and other documents for the construction and lease of a 40,000 square foot state of the art facility in Arlington, Tennessee which will be used for manufacturing and distribution. The lease documents included an option to purchase this facility for approximately $12.0 million upon completion of construction. In December 2018, we exercised our option to purchase the facility once construction is complete.

Quarterly Results of Operatio_2

Quarterly Results of Operations (Tables)	12 Months Ended
	Dec. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	2018 First quarter Second quarter Third quarter Fourth quarter Net sales $ 198,537 $ 205,400 $ 194,106 $ 238,147 Cost of sales 41,139 45,558 44,307 49,149 Gross profit 157,398 159,842 149,799 188,998 Operating expenses: Selling, general and administrative 137,248 140,826 139,223 160,664 Research and development 13,899 14,665 13,829 16,749 Amortization of intangible assets 7,141 6,009 5,881 7,699 Total operating expenses 158,288 161,500 158,933 185,112 Operating (loss) income (890 ) (1,658 ) (9,134 ) 3,886 Net loss from continuing operations, net of tax (19,907 ) (90,621 ) (35,829 ) (22,947 ) (Loss) income from discontinued operations, net of tax (5,607 ) 22,923 (6,696 ) (10,821 ) Net loss $ (25,514 ) $ (67,698 ) $ (42,525 ) $ (33,768 ) Net loss, continuing operations per share, basic and diluted $ (0.19 ) $ (0.85 ) $ (0.32 ) $ (0.18 ) Net loss income per share, basic and diluted $ (0.24 ) $ (0.64 ) $ (0.38 ) $ (0.27 ) Weighted-average number of shares outstanding-basic and diluted 105,904 106,095 113,043 125,323 2017 First Second Third Fourth Net sales $ 177,191 $ 179,693 $ 170,503 $ 217,602 Cost of sales 37,126 38,122 38,421 47,278 Gross profit 140,065 141,571 132,082 170,324 Operating expenses: Selling, general and administrative 129,834 130,818 131,421 133,149 Research and development 12,432 12,547 11,992 13,144 Amortization of intangible assets 7,397 6,999 7,178 6,822 Total operating expenses 149,663 150,364 150,591 153,115 Operating (loss) income (9,598 ) (8,793 ) (18,509 ) 17,209 Net (loss) income from continuing operations, net of tax (36,707 ) (20,960 ) (34,122 ) 26,852 (Loss) income from discontinued operations, net of tax (21,992 ) (20,202 ) (97,748 ) 2,281 Net (loss) income $ (58,699 ) $ (41,162 ) $ (131,870 ) $ 29,133 Net (loss) income, continuing operations per share, basic $ (0.35 ) $ (0.20 ) $ (0.33 ) $ 0.26 Net (loss) income, continuing operations per share, diluted $ (0.35 ) $ (0.20 ) $ (0.33 ) $ 0.25 Net (loss) income per share, basic $ (0.57 ) $ (0.39 ) $ (1.26 ) $ 0.28 Net (loss) income per share, diluted $ (0.57 ) $ (0.39 ) $ (1.26 ) $ 0.27 Weighted-average number of shares outstanding-basic 103,663 104,377 104,836 105,195 Weighted-average number of shares outstanding-diluted 103,663 104,377 104,836 106,578

Segment Data (Tables)

Segment Data (Tables)	12 Months Ended
	Dec. 30, 2018
Segment Data [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Total assets by business segment as of December 30, 2018 and December 31, 2017 are as follows (in thousands): December 30, 2018 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate Total Total assets $ 940,075 $ 923,036 $ 272,127 $ 559,163 $ 2,694,401 December 31, 2017 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate Total Total assets $ 490,528 $ 929,930 $ 301,985 $ 406,281 $ 2,128,724 Selected financial information related to our segments is presented below for the fiscal years ended December 30, 2018 , December 31, 2017 , and December 25, 2016 (in thousands): Fiscal year ended December 30, 2018 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 337,433 $ 286,105 $ 212,652 $ — $ 836,190 Depreciation expense 11,131 12,439 13,004 22,923 59,497 Amortization expense — — — 26,730 26,730 Segment operating income (loss) $ 96,153 $ 97,644 $ 1,492 $ (190,720 ) $ 4,569 Other: Transaction and transition expenses 12,013 Inventory step-up amortization 352 Operating loss (7,796 ) Interest expense, net 80,247 Other expense, net 81,797 Loss before income taxes $ (169,840 ) Capital expenditures $ 21,153 $ 26,346 $ 17,566 $ 6,402 $ 71,467 Fiscal year ended December 31, 2017 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 309,713 $ 244,798 $ 190,478 $ — $ 744,989 Depreciation expense 12,532 10,211 12,366 21,723 56,832 Amortization expense — — — 28,396 28,396 Segment operating income (loss) $ 79,889 $ 78,866 $ 3,631 $ (178,642 ) $ (16,256 ) Other: Transaction and transition expenses 12,400 Incentive and indirect tax projects (8,965 ) Operating loss (19,691 ) Interest expense, net 74,644 Other expense, net 5,570 Loss before income taxes $ (99,905 ) Capital expenditures $ 19,355 $ 22,897 $ 19,555 $ 1,667 $ 63,474 Fiscal year ended December 25, 2016 U.S. Lower Extremities & Biologics U.S. Upper Extremities International Extremities & Biologics Corporate 1 Total Net sales from external customers $ 300,847 $ 206,700 $ 182,815 $ — $ 690,362 Depreciation expense 13,000 11,190 11,427 20,213 55,830 Amortization expense — — — 28,841 28,841 Segment operating income (loss) $ 85,645 $ 65,231 $ 5,872 $ (202,261 ) $ (45,513 ) Other: Inventory step-up amortization 37,689 Transaction and transition expenses 36,374 Legal settlement 1,800 Management changes 1,348 Costs associated with new convertible debt 234 Operating loss (122,958 ) Interest expense, net 58,530 Other income, net (3,148 ) Loss before income taxes $ (178,340 ) Capital expenditures $ 13,145 $ 10,101 $ 13,517 $ 13,336 $ 50,099
Revenue from External Customers by Products and Services [Table Text Block]	Net sales by geographic region by product line are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 United States Lower extremities $ 250,735 $ 228,044 $ 222,936 Upper extremities 281,314 239,965 201,579 Biologics 83,077 78,361 74,603 Sports med & other 8,412 8,141 8,429 Total United States $ 623,538 $ 554,511 $ 507,547 EMEAC Lower extremities $ 46,342 $ 42,333 $ 43,805 Upper extremities 87,647 73,243 66,819 Biologics 8,312 8,445 8,149 Sports med & other 11,074 13,751 13,405 Total EMEAC $ 153,375 $ 137,772 $ 132,178 Other Lower extremities $ 14,407 $ 16,140 $ 18,896 Upper extremities 26,813 21,456 19,683 Biologics 17,445 13,831 10,734 Sports med & other 612 1,279 1,324 Total other $ 59,277 $ 52,706 $ 50,637 Total net sales $ 836,190 $ 744,989 $ 690,362
Revenue from External Customers by Geographic Areas [Table Text Block]	Net sales by geographic region by product line are as follows (in thousands): Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016 United States Lower extremities $ 250,735 $ 228,044 $ 222,936 Upper extremities 281,314 239,965 201,579 Biologics 83,077 78,361 74,603 Sports med & other 8,412 8,141 8,429 Total United States $ 623,538 $ 554,511 $ 507,547 EMEAC Lower extremities $ 46,342 $ 42,333 $ 43,805 Upper extremities 87,647 73,243 66,819 Biologics 8,312 8,445 8,149 Sports med & other 11,074 13,751 13,405 Total EMEAC $ 153,375 $ 137,772 $ 132,178 Other Lower extremities $ 14,407 $ 16,140 $ 18,896 Upper extremities 26,813 21,456 19,683 Biologics 17,445 13,831 10,734 Sports med & other 612 1,279 1,324 Total other $ 59,277 $ 52,706 $ 50,637 Total net sales $ 836,190 $ 744,989 $ 690,362

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 30, 2018
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for doubtful accounts and sales returns	Wright Medical Group N.V. Schedule II-Valuation and Qualifying Accounts (In thousands) Balance at Beginning of Period Charged to Cost and Expenses Deductions and Other Balance at End of Period Allowance for doubtful accounts: For the period ended: December 30, 2018 $ 4,328 $ 189 $ (1,472 ) $ 3,045 December 31, 2017 $ 4,469 $ 1,243 $ (1,384 ) $ 4,328 December 25, 2016 $ 1,189 $ 3,475 $ (195 ) $ 4,469

Organization and Description _2

Organization and Description of Business (Details)	12 Months Ended
	Dec. 30, 2018countriessegment
Business Acquisition [Line Items]
Number of Operating Segments | segment	3
Number of countries in which entity operates | countries	50

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Estimated Useful Lives of Property Plant and Equipment (Details)	12 Months Ended
	Dec. 30, 2018
Surgical instruments [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	6 years
Minimum [Member] | Land improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	15 years
Minimum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	10 years
Minimum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Minimum [Member] | Furniture, fixtures and office equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Maximum [Member] | Land improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Maximum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	40 years
Maximum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	14 years
Maximum [Member] | Furniture, fixtures and office equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	14 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Intangible Assets (Details)	12 Months Ended
	Dec. 30, 2018
Completed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Distribution channels [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	11 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	4 years
Other intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Valuation of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Assets
Cash and cash equivalents	$ 191,351	$ 167,740
Cash and cash equivalents	191,351	167,740	$ 262,300
Liabilities
Derivative Liability, Fair Value, Gross Liability	304,372	170,280
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	140	5,320	$ 8,688
Fair Value, Measurements, Recurring [Member]
Available-for-sale marketable securities
Total assets	513,397	339,836
Liabilities
Total liabilities	341,426	231,793
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale marketable securities
Total assets	191,351	167,740
Liabilities
Total liabilities	420	42,325
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Available-for-sale marketable securities
Total assets	0	0
Liabilities
Total liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Available-for-sale marketable securities
Total assets	322,046	172,096
Liabilities
Total liabilities	341,006	189,468
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent Consideration Fair Value	420	42,325
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Contingent Consideration Fair Value	420	42,325
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Contingent Consideration Fair Value	0	0
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Contingent Consideration Fair Value	0	0
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent Consideration Fair Value	19,248	19,188
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Contingent Consideration Fair Value	0	0
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Contingent Consideration Fair Value	0	0
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Contingent Consideration Fair Value	$ 19,248	$ 19,188

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Accounting Policies [Abstract]
Interest	$ 30,552	$ 24,641	$ 18,678
Income taxes	$ 6,254	$ 7,359	$ 4,334

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Business Acquisition [Line Items]
Shipping, Handling and Transportation Costs	$ 52,000	$ 49,400	$ 44,000
Summary of Significant Accounting Policies [Abstract]
Inventory write-down	20,913	19,171	22,046
Stock-based compensation expense	26,100	19,400	14,400
Contingent consideration at fair value, current	3,427	1,168
Gain (loss) on foreign currency contracts not designated as hedging instruments		(4,600)	800
Continuing Operations [Member]
Summary of Significant Accounting Policies [Abstract]
Inventory write-down	20,900	19,200	21,500
Inventory Valuation and Obsolescence [Member] | Continuing Operations [Member]
Summary of Significant Accounting Policies [Abstract]
Inventory write-down	4,400	3,100	4,100
Allowance for Doubtful Accounts [Member]
Business Acquisition [Line Items]
Valuation Allowances and Reserves, Balance	$ 3,045	4,328	$ 4,469	$ 1,189
Allowance for Doubtful Accounts Receivable		$ 4,300

Summary of Significant Accoun_9

Summary of Significant Accounting Policies Fair Value Measurements (Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs (Level 3)) (Details) (Details) - USD ($) $ in Thousands	Feb. 13, 2015	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Dec. 30, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		$ (700)	$ (300)	$ (400)	$ (400)
2017 Notes Conversion Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ 49,000
Contingent Consideration [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value		$ 19,248				$ 19,188			$ 19,248
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements									919
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency									810
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings						$ 200	$ (100)	$ (200)	$ 1,789

Summary of Significant Accou_10

Summary of Significant Accounting Policies Shipping and Handling (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Accounting Policies [Abstract]
Instrument Depreciation Expense	$ 28.4	$ 27.1	$ 26.1
Shipping, Handling and Transportation Costs	$ 52	$ 49.4	$ 44

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 24, 2019	Oct. 10, 2018	Aug. 27, 2018	Dec. 14, 2017	Oct. 21, 2016	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments														$ (917)	$ 71,981
Goodwill						$ 1,268,954				$ 933,662				1,268,954	933,662	$ 851,042
InventoryStepUpAmortizationExpenseContinuingOperations																37,700
Amortization of intangible assets						7,699	$ 5,881	$ 6,009	$ 7,141	6,822	$ 7,178	$ 6,999	$ 7,397	$ 26,730	28,396	28,841	[1]
Business Combination, Integration Related Costs						$ 7,800	2,000	1,300	900
Share Price						$ 26.51								$ 26.51
Business Combination, Acquisition Related Costs, Transaction														$ 12,013	12,400	36,374
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability														140	5,320	8,688
Stock-based compensation expense														26,100	19,400	14,400
Goodwill														351,445
Proceeds from Issuance or Sale of Equity														448,924
Net sales						$ 238,147	194,106	205,400	198,537	217,602	170,503	179,693	177,191	836,190	744,989	690,362
Operating Income (Loss)						3,886	$ (9,134)	$ (1,658)	$ (890)	17,209	$ (18,509)	$ (8,793)	$ (9,598)	(7,796)	(19,691)	(122,958)
Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs		$ 435,000
Business Combination, Acquired Receivables, Gross Contractual Amount		5,800
Business Acquisition, Pro Forma Revenue														861,475	769,111
Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents (Deprecated 2013-01-31)		309
Business Combination, Acquired Receivable, Fair Value		4,352
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory		2,686
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets		486
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets		90,279
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		1,446
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		81,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		(3,622)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		82,431
InventoryStepUpAmortizationExpenseContinuingOperations						400								400
Amortization of intangible assets														1,900
Business Combination, Consideration Transferred		433,876
Allowance for Doubtful Accounts Receivable, Recoveries		1,400
Business Combination, Acquisition Related Costs, Transaction														6,500
Business Acquisition, Pro Forma Net Income (Loss)														(179,800)	(68,722)
Current liabilities		(4,226)
Total liabilities assumed		(7,848)
Cash Acquired from Acquisition		$ 1,100
Net sales														9,500
Operating Income (Loss)														2,400
IMASCAP SAS [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs				$ 62,300
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares				661,753
Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents (Deprecated 2013-01-31)				$ 2,559
Contingent Consideration Fair Value				17,800
Business Combination, Acquired Receivable, Fair Value				102
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				925
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets				14,471
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				20
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				10,900
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent				(2,343)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net				9,069
Business Combination, Consideration Transferred				80,133
Current liabilities				(2,173)
Long-term debt				(886)
Total liabilities assumed				(5,402)
Subsequent Event [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Cash Acquired from Acquisition	$ 700
Pro Forma [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs, Transaction														15,300
Customer Relationships [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		15 years
Technology-Based Intangible Assets [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 28,000
Finite-Lived Intangible Asset, Useful Life		7 years
Technology-Based Intangible Assets [Member] | IMASCAP SAS [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 5,600
Finite-Lived Intangible Asset, Useful Life				6 years
In Process Research and Development [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 1,000
In Process Research and Development [Member] | IMASCAP SAS [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 5,300
Large Joints [Member]
Business Acquisition [Line Items]
Purchase Price Discontinued Operations					$ 29,700
Net Working Capital Not Transferred in Disposal					$ 11,100
Cash [Member] | IMASCAP SAS [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs				46,700
Common Stock [Member] | IMASCAP SAS [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs				$ 15,600
UNITED STATES | Lower Extremities & Biologics [Member]
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments														0
Goodwill						$ 569,970				$ 218,525				569,970	218,525	218,525
Net sales														337,433	$ 309,713	$ 300,847
UNITED STATES | Lower Extremities & Biologics [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Goodwill														$ 351,445
Customer Relationships [Member] | Finite-Lived Intangible Assets [Member] | Cartiva, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 52,000
Sale of Stock [Domain]
Business Acquisition [Line Items]
Proceeds from Issuance or Sale of Equity			$ 423,000
Common Stock [Member]
Business Acquisition [Line Items]
Stock Issued During Period, Shares, Other			18,200,000											18,248,932
[1]	The Corporate category primarily reflects general and administrative expenses not specifically associated with the U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics segments. These non-allocated corporate expenses relate to global administrative expenses that support all segments, including salaries and benefits of certain executive officers and expenses such as: information technology administration and support; corporate headquarters; legal, compliance, and corporate finance functions; insurance; and all share-based compensation.

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	May 08, 2018	Oct. 21, 2016	May 20, 2016	Sep. 01, 2015	Feb. 13, 2015	Jan. 09, 2014	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017	Sep. 25, 2016	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Weighted Average Number of Shares Outstanding, Basic and Diluted							125,323	113,043	106,095	105,904	105,195	104,836	104,377	103,663		112,592	104,531	102,968
Loss Contingency, Receivable, Period Increase (Decrease)																$ (42,044)	$ 0	$ 0
Payments for Legal Settlements																		1,800
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax																0	0	(21,342)
Discontinued Operation, Tax Effect of Discontinued Operation							$ 3,800	$ 2,200	$ (6,200)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent							(10,821)	$ (6,696)	$ 22,923	$ (5,607)	$ 2,281	$ (97,748)	$ (20,202)	$ (21,992)		$ (201)	$ (137,661)	$ (267,439)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Basic Share																$ 0	$ (1.32)	$ (2.60)
Goodwill							$ 1,268,954				$ 933,662					$ 1,268,954	$ 933,662	$ 851,042
Repayments of Debt					$ 292,000
Payments for Repurchase of Warrants																23,972	0	3,319
Proceeds from Hedge, Financing Activities																34,553	0	3,892
Insurance Recoveries																101,900
OrthoRecon Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Product Liability Accrual, Period Expense																	94,000	196,600
Purchase Price Discontinued Operations						$ 283,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax						$ 24,300
Disposal Group, Including Discontinued Operation, Revenue																0	0	0
Disposal Group, Including Discontinued Operation, General and Administrative Expense																(746)	135,235	247,978
Cash Provided by (Used in) Operating Activities, Discontinued Operations																91,400	221,600	16,700
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax																746	(135,235)	(247,978)
Discontinued Operation, Tax Effect of Discontinued Operation																221	(1,707)	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent																525	(133,528)	(247,978)
Large Joints Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Investing Activities, Discontinued Operations																		20,700
Disposal Group, Including Discontinued Operation, Revenue																		35,318
Disposal Group, Including Discontinued Operation, Costs of Goods Sold																		20,244
Disposal Group, Including Discontinued Operation, General and Administrative Expense																		18,808
Discontinued Operation, Income (Loss) from Discontiuned Operation Before Impairment Loss and Income Taxes																		(3,734)
Impairment of Long-Lived Assets to be Disposed of																		21,342
Cash Provided by (Used in) Operating Activities, Discontinued Operations																2,800	6,500	5,200
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax																		(25,076)
Discontinued Operation, Tax Effect of Discontinued Operation																		(5,615)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent																700	$ 4,100	(19,461)
Large Joints [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase Price Discontinued Operations		$ 29,700
Net Working Capital Not Transferred in Disposal		$ 11,100
PROFEMUR Titanium Modular Neck Product [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss Contingency, Receivable, Period Increase (Decrease)				$ 25,000
2020 convertibledebt [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Extinguishment of Debt, Amount													$ 45,000			45,000
Repayments of Debt																44,600
Payments for Repurchase of Warrants			$ 3,300
Proceeds from Hedge, Financing Activities			600
2020 Conversion Derivative [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements			400													$ 55,643
2020 Conversion Derivative [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Derivative, Cash Received on Hedge			$ 3,900
Insurance Carrier [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Legal Settlements	$ 30,750
Insurance Policy Limit	25,000
Insurance Policy, Costs And Interest Received	$ 5,750
Columbia [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Insurance Recoveries															$ 10,000			$ 60,000

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 30, 2018	Dec. 30, 2018	Dec. 25, 2016	Oct. 10, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
InventoryStepUpAmortizationExpenseContinuingOperations			$ 37,700
Inventory, Raw Materials, Net of Reserves	$ 9,612	$ 9,612			$ 10,816
Inventory, Work in Process, Net of Reserves	26,839	26,839			28,581
Inventory, Finished Goods, Net of Reserves	144,239	144,239			128,747
Total Inventory	180,690	180,690			$ 168,144
Cartiva, Inc. [Member]
Business Acquisition [Line Items]
InventoryFairValueStepUp	1,000	1,000		$ 1,400
InventoryStepUpAmortizationExpenseContinuingOperations	$ 400	$ 400

Derivatives and Fair Value of_3

Derivatives and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	May 20, 2016	Feb. 13, 2015	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016	Jun. 28, 2018
Schedule of Marketable Securities [Line Items]
Cash and Cash Equivalents, at Carrying Value			$ 191,351				$ 167,740			$ 191,351	$ 167,740	$ 262,300
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings			700	$ 300	$ 400	$ 400
Cash and Cash Equivalents, Fair Value Disclosure			191,351				167,740			191,351	167,740
Restricted Cash and Cash Equivalents, Current							150,000				150,000
Derivative Liability, Fair Value, Gross Liability			304,372				170,280			304,372	170,280
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability										$ 140	5,320	$ 8,688
2020 Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Assumptions, Expected Volatility Rate										34.48%
Derivative Liability, Fair Value, Gross Liability			17,386				44,132			$ 17,386	44,132
2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			17,822				45,033			$ 17,822	45,033
Wright Medical Group, Inc. [Member] | 2020 Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Inputs, Entity Credit Risk										4.67%
Wright Medical Group, Inc. [Member] | 2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Assumptions, Expected Volatility Rate										34.48%
DEUTSCHE BANK SUPER X [Member] | 2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Inputs, Entity Credit Risk										1.38%
JP Morgan Chase Bank [Member] | 2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Inputs, Entity Credit Risk										0.30%
WELLS FARGO LIQUIDITY CROSS ATS [Member] | 2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value Inputs, Entity Credit Risk										0.25%
Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Total Assets			513,397				339,836			$ 513,397	339,836
Total Liabilities			341,426				231,793			341,426	231,793
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Marketable Securities [Line Items]
Total Assets			191,351				167,740			191,351	167,740
Total Liabilities			420				42,325			420	42,325
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Marketable Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure			0				0			0	0
Total Assets			0				0			0	0
Total Liabilities			0				0			0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure			0				0			0	0
Total Assets			322,046				172,096			322,046	172,096
Total Liabilities			341,006				189,468			341,006	189,468
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			19,248				19,188			19,248	19,188
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			0				0			0	0
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			0				0			0	0
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			19,248				19,188			19,248	19,188
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			420				42,325			420	42,325
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			420				42,325			420	42,325
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			0				0			0	0
Contingent Value Rights [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value			0				0			0	0
2021 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			188,301				127,063			188,301	127,063
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings										61,238
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
2021 Notes Hedges [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			188,301				127,063			188,301	127,063
2020 Notes Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			17,822				45,033			17,822	45,033
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings										7,342
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements										(34,553)
2020 Notes Hedges [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			17,822				45,033			17,822	45,033
2020 Notes Hedges [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset							45,033				45,033
2020 Notes Hedges [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			0				0			0	0
2020 Notes Hedges [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			0				0			0	0
2023 Note Hedges [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			115,923							115,923
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases										141,278
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings										(25,355)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements										0
Derivative Asset, Fair Value, Gross Asset			115,923							115,923
2023 Note Hedges [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Asset, Fair Value, Gross Asset			115,923							115,923
2020 Warrants Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements										23,972
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases										(27,308)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings										3,336
2021 Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			(187,539)				(126,148)			(187,539)	(126,148)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings										(61,391)
2021 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Liability, Fair Value, Gross Liability			187,539				126,148			187,539	126,148
2020 Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ 400									55,643
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			(17,386)				(44,132)			(17,386)	(44,132)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases										0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings										(28,897)
2020 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Liability, Fair Value, Gross Liability			17,386				44,132			17,386	44,132
2020 Conversion Derivative [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Derivative Liability, Fair Value, Gross Liability							44,132				44,132
Contingent Consideration [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										810
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements										919
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			(19,248)				(19,188)			(19,248)	(19,188)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings							(200)	$ 100	$ 200	(1,789)
2017 Notes Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		$ 49,000
2023 Conversion Derivative [Member]
Schedule of Marketable Securities [Line Items]
Long-term Debt, Fair Value													$ 124,600
Fair Value, Measurement with Unobservable Inputs Reconciliation, Currency										0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			(116,833)							(116,833)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases										(124,625)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings										7,792
2023 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Marketable Securities [Line Items]
Derivative Liability, Fair Value, Gross Liability			116,833							116,833
2023 Conversion Derivative [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Marketable Securities [Line Items]
Derivative Liability, Fair Value, Gross Liability			$ 116,833							116,833
WG Healthcare [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value							17,800				17,800
SSP - Distribution Business [Member]
Schedule of Marketable Securities [Line Items]
Contingent Consideration Fair Value							$ 900				$ 900
SSP - Distribution Business [Member] | Contingent Consideration [Member]
Schedule of Marketable Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases										$ 0

Derivatives and Fair Value of_4

Derivatives and Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) $ / shares in Units, € in Millions

Feb. 24, 2019USD ($)

Jul. 30, 2018USD ($)

Jun. 28, 2018USD ($)counterparty

May 20, 2016USD ($)counterparty

Feb. 13, 2015USD ($)counterparty

Aug. 31, 2008

Mar. 01, 2013$ / shares

Dec. 30, 2018USD ($)

Sep. 30, 2018USD ($)

Jul. 01, 2018USD ($)

Apr. 01, 2018USD ($)

Dec. 31, 2017USD ($)

Sep. 24, 2017USD ($)

Jun. 25, 2017USD ($)

Mar. 26, 2017USD ($)

Sep. 30, 2018

Sep. 25, 2016

Dec. 30, 2018USD ($)$ / shares

Dec. 31, 2017USD ($)

Dec. 25, 2016USD ($)

Dec. 30, 2018EUR (€)

Dec. 31, 2017EUR (€)

Dec. 14, 2017USD ($)

Aug. 31, 2012USD ($)

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

ThresholdForConversionAsPercentOfConversionPrice

130.00%

130.00%

130.00%

Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability

$ 140,000

$ 5,320,000

$ 8,688,000

Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments

(4,600,000)

800,000

Current Portion of CVR Contingent Consideration Liability

$ 420,000

$ 42,044,000

420,000

42,044,000

Derivative Liability, Fair Value, Gross Liability

304,372,000

170,280,000

304,372,000

170,280,000

Non Cash Adjustment Derivative Fair Value

$ 1,600,000

$ (200,000)

$ 32,900,000

$ 1,700,000

(600,000)

$ (200,000)

$ (4,300,000)

$ 400,000

$ 35,934,000

(4,797,000)

(28,273,000)

Debt Instrument, Convertible, Minimum Consecutive Period

20 days

20 days

20 days

Debt Instrument, Convertible, Trading Period

30 days

30 days

30 days

Proceeds from Hedge, Financing Activities

$ 34,553,000

0

$ 3,892,000

2021 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

ThresholdForConversionAsPercentOfConversionPrice

130.00%

Convertible senior notes

$ 533,400,000

533,400,000

Stated percentage rate

2.25%

Debt Instrument, Convertible, Minimum Consecutive Period

20 days

Debt Instrument, Convertible, Trading Period

30 days

2023 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Debt Instrument, Face Amount

$ 675,000,000

675,000,000

675,000,000

Convertible senior notes

680,300,000

$ 680,300,000

Stated percentage rate

1.625%

Number of Counterparties | counterparty

2

Debt Instrument, Convertible, Trading Period

120 days

Debt Conversion, Converted Instrument, Amount Delivered

$ 1,138.70

2017 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

ThresholdForConversionAsPercentOfConversionPrice

130.00%

Stated percentage rate

2.00%

Debt Instrument, Convertible, Minimum Consecutive Period

20 days

Debt Instrument, Convertible, Trading Period

30 days

2020 convertibledebt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

ThresholdForConversionAsPercentOfConversionPrice

130.00%

Debt Conversion, Converted Instrument, Amount

400,900,000

Stated percentage rate

2.00%

Debt Instrument, Convertible, Minimum Consecutive Period

20 days

Debt Instrument, Convertible, Trading Period

30 days

Proceeds from Hedge, Financing Activities

$ 600,000

Proceeds from Warrant Exercises

$ 10,600,000

2020 Conversion Derivative [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Proceeds from Hedge, Financing Activities

$ 27,300,000

Carrying (Reported) Amount, Fair Value Disclosure [Member] | 2021 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Long-term Debt, Gross

$ 395,000,000

395,000,000

395,000,000

$ 395,000,000

395,000,000

Carrying (Reported) Amount, Fair Value Disclosure [Member] | 2017 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Long-term Debt, Gross

$ 300,000,000

Carrying (Reported) Amount, Fair Value Disclosure [Member] | 2020 convertibledebt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Convertible senior notes

196,900,000

196,900,000

Long-term Debt, Gross

$ 632,500,000

186,589,000

587,500,000

186,589,000

587,500,000

IMASCAP SAS [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Contingent Consideration Fair Value

$ 17,800,000

WG Healthcare [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Contingent Consideration Fair Value

17,800,000

17,800,000

Technical Milestones And Sales Earnouts [Member] | IMASCAP SAS [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Business Combination, Contingent Consideration, Liability

19,200,000

17,800,000

$ 19,200,000

17,800,000

€ 16.7

€ 15.1

BMTI Payment of Conditional Value Rights [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Price per share of contingent consideration | $ / shares

$ 6.50

$ 3.50

Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability

$ 98,100,000

2021 Notes Hedges [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Number of Counterparties | counterparty

2

2021 Notes Hedges [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Asset, Fair Value, Gross Asset

188,301,000

127,063,000

188,301,000

127,063,000

2023 Note Hedges [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Asset, Fair Value, Gross Asset

115,923,000

115,923,000

Number of Counterparties | counterparty

2

Derivative, Cost of Hedge

$ 141,300,000

2023 Note Hedges [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Asset, Fair Value, Gross Asset

115,923,000

115,923,000

2020 Settled Hedges [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Proceeds From Derivatives Settled

34,600,000

2020 Warrants Derivative [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Payments For Warrants

$ 24,000,000

2020 Conversion Derivative [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Proceeds From Derivatives Settled

55,600,000

2020 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Liability, Fair Value, Gross Liability

17,386,000

44,132,000

17,386,000

44,132,000

2020 Conversion Derivative [Member] | Fair Value, Measurements, Recurring [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Liability, Fair Value, Gross Liability

$ 44,132,000

$ 44,132,000

2023 Conversion Derivative [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Convertible senior notes

$ 124,600,000

2023 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Liability, Fair Value, Gross Liability

116,833,000

116,833,000

2023 Conversion Derivative [Member] | Fair Value, Measurements, Recurring [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative Liability, Fair Value, Gross Liability

$ 116,833,000

$ 116,833,000

2023 Conversion Derivative [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair Value Assumptions, Expected Volatility Rate

31.90%

Derivative, Gain (Loss) on Derivative, Net

$ 7,792,000

2023 Note Hedges [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Derivative, Gain (Loss) on Derivative, Net

(25,355,000)

2020 Notes Hedges [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Number of Counterparties | counterparty

3

Derivative, Cost of Hedge

$ 144,800,000

2023 Change in Derivative fair Value [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Non Cash Adjustment Derivative Fair Value

$ (17,563,000)

Subsequent Event [Member] | 2023 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Debt Instrument, Face Amount

$ 814,600,000

Proceeds from Warrant Exercises

8,900,000

Subsequent Event [Member] | 2020 convertibledebt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Debt Instrument, Face Amount

56,500,000

Debt Conversion, Converted Instrument, Amount

130,100,000

Subsequent Event [Member] | Additional 2023 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Debt Instrument, Face Amount

139,600,000

2020 convertibledebt [Member] | 2021 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Extinguishment Of Debt, Amount Delivered Per Incremental Amount Exchanged

$ 990

2020 convertibledebt [Member] | Subsequent Event [Member] | 2023 Convertible Debt [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Extinguishment Of Debt, Amount Delivered Per Incremental Amount Exchanged

$ 1,072.40

Derivatives and Fair Value of_5

Derivatives and Fair Value of Financial Instruments Derivatives (Details) $ / shares in Units, $ in Thousands, € in Millions	May 20, 2016USD ($)	Feb. 13, 2015USD ($)	Mar. 01, 2013$ / shares	Dec. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Jul. 01, 2018USD ($)	Apr. 01, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 24, 2017USD ($)	Jun. 25, 2017USD ($)	Mar. 26, 2017USD ($)	Mar. 31, 2015USD ($)	Dec. 30, 2018USD ($)$ / shares	Oct. 28, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 25, 2016USD ($)	Dec. 31, 2012USD ($)	Dec. 30, 2018EUR (€)	Dec. 31, 2017EUR (€)	Dec. 14, 2017USD ($)	Aug. 31, 2012USD ($)
Derivatives, Fair Value [Line Items]
Restricted Cash and Cash Equivalents, Current								$ 150,000							$ 150,000
Payment of contingent consideration - initial valuation													$ (919)		(1,429)	$ (1,035)
Proceeds from 2017 bond hegdes settlement		$ 10,000
Long-term Debt				$ 1,286,542									1,286,542
Debt Discount at Time of Issuance																					$ 48,100
Payments for (Proceeds from) Hedge, Financing Activities																	$ 56,200
Derivative Liability, Fair Value, Gross Liability				304,372				170,280					304,372		170,280
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings				700	$ 300	$ 400	$ 400
Non Cash Adjustment Derivative Fair Value				(1,600)	$ 200	$ (32,900)	$ (1,700)	600	$ 200	$ 4,300	$ (400)		(35,934)		4,797	28,273
Repayments of Debt		292,000
Payments for Repurchase of Warrants													$ 23,972		0	3,319
2023 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													31.90%
Derivative, Gain (Loss) on Derivative, Net													$ 7,792
2020 Warrants Derivative [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net															0
2021 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													42.20%
Derivative, Gain (Loss) on Derivative, Net													$ (61,391)		35,453
2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net													61,238		(32,032)
2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset				17,822				45,033					17,822		45,033
Derivative, Gain (Loss) on Derivative, Net													$ 7,342		(32,199)
2017 Notes Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Debt Discount at Time of Issuance																					$ 48,100
Repayments of Debt												$ 240,000			3,600	240,000
Derivative, Cash Received on Hedge												70,000				70,000
2020 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													34.48%
Derivative Liability, Fair Value, Gross Liability				17,386				44,132					$ 17,386		44,132
Derivative, Gain (Loss) on Derivative, Net													(28,897)		33,626
Debt Instrument, Unamortized Discount		$ 149,800
Derivative, Cash Received on Hedge	$ 3,900
2023 Note Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net													(25,355)
Subsequent Event [Member]
Derivatives, Fair Value [Line Items]
Cash Payment, Contingent Consideration														$ 42,000
2021 Convertible Debt [Member]
Derivatives, Fair Value [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.25%
Debt Instrument, Unamortized Discount	$ 117,200			69,382				89,332					69,382		89,332
2020 convertibledebt [Member]
Derivatives, Fair Value [Line Items]
Extinguishment of Debt, Amount										$ 45,000			45,000
Repayments of Debt													44,600
Debt Instrument, Interest Rate, Stated Percentage		2.00%
Debt Instrument, Unamortized Discount				11,642				66,418					11,642		66,418
Payments for Repurchase of Warrants	3,300
2017 Convertible Debt [Member]
Derivatives, Fair Value [Line Items]
Extinguishment of Debt, Amount															54,400
Repayments of Debt															56,300
Debt Instrument, Interest Rate, Stated Percentage																					2.00%
Debt Instrument, Periodic Payment, Interest		$ 2,400
Payments for Repurchase of Warrants												$ 60,000				$ 60,000
2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Cost of Hedge		144,800
2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Cost of Hedge	99,800
2021 Change in Derivative fair Value [Member]
Derivatives, Fair Value [Line Items]
Non Cash Adjustment Derivative Fair Value													153		(3,421)
2020 Change in Derivative Fair Value [Member]
Derivatives, Fair Value [Line Items]
Non Cash Adjustment Derivative Fair Value													$ 18,219		(1,427)
WELLS FARGO LIQUIDITY CROSS ATS [Member] | 2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.25%
DEUTSCHE BANK SUPER X [Member] | 2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													1.38%
Wright Medical Group, Inc. [Member] | 2023 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													3.72%
Wright Medical Group, Inc. [Member] | 2021 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													4.50%
Wright Medical Group, Inc. [Member] | 2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													42.20%
Wright Medical Group, Inc. [Member] | 2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													34.48%
Wright Medical Group, Inc. [Member] | 2020 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													4.67%
Wright Medical Group, Inc. [Member] | 2023 Note Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Assumptions, Expected Volatility Rate													31.90%
JP Morgan Chase Bank [Member] | 2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.45%
JP Morgan Chase Bank [Member] | 2020 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.30%
JP Morgan Chase Bank [Member] | 2023 Note Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.56%
Bank of America [Member] | 2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.46%
Bank of America [Member] | 2023 Note Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair Value Inputs, Entity Credit Risk													0.59%
Fair Value, Inputs, Level 3 [Member] | 2021 Notes Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset				188,301				127,063					$ 188,301		127,063
2017 Notes Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		49,000
2021 Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings													(61,391)
2021 Conversion Derivative [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability				187,539				126,148					187,539		126,148
Reported Value Measurement [Member] | 2021 Convertible Debt [Member]
Derivatives, Fair Value [Line Items]
Long-term Debt, Gross	395,000			395,000				395,000					395,000		395,000
Reported Value Measurement [Member] | 2020 convertibledebt [Member]
Derivatives, Fair Value [Line Items]
Long-term Debt, Gross		$ 632,500		186,589				587,500					$ 186,589		587,500
Reported Value Measurement [Member] | 2017 Convertible Debt [Member]
Derivatives, Fair Value [Line Items]
Long-term Debt, Gross																					$ 300,000
2021 Convertible Debt [Member]
Derivatives, Fair Value [Line Items]
Derivative, Cost of Hedge	99,800
WG Healthcare [Member]
Derivatives, Fair Value [Line Items]
Contingent Consideration Fair Value								17,800							17,800
SSP - Distribution Business [Member]
Derivatives, Fair Value [Line Items]
Contingent Consideration Fair Value								900							900
IMASCAP SAS [Member]
Derivatives, Fair Value [Line Items]
Contingent Consideration Fair Value																				$ 17,800
Fair Value Inputs, Discount Rate													12.00%
Debt Exchange [Member] | 2017 Notes Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	1,900
Debt Repayment [Member] | 2017 Notes Conversion Derivative [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ 100
AUGMENT Bone Graft Payment of Conditional Value Rights, Condition One [Member]
Derivatives, Fair Value [Line Items]
Price per share of contingent consideration | $ / shares													$ 1.50
Technical Milestones And Sales Earnouts [Member] | IMASCAP SAS [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Liability				19,200				17,800					$ 19,200		17,800			€ 16.7	€ 15.1
Technical Milestones [Member] | IMASCAP SAS [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Liability				12,700				11,900					$ 12,700		11,900
Fair Value Inputs, Discount Rate													6.00%
Sales Earnouts [Member] | IMASCAP SAS [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Liability				6,500				$ 5,900					$ 6,500		$ 5,900
BMTI Payment of Conditional Value Rights [Member]
Derivatives, Fair Value [Line Items]
Price per share of contingent consideration | $ / shares			$ 6.50										$ 3.50
Fair Value, Measurements, Recurring [Member] | AUGMENT Bone Graft Payment of Conditional Value Rights, Condition One [Member] | Subsequent Event [Member]
Derivatives, Fair Value [Line Items]
Contingent Consideration Fair Value														$ 40,000
Fair Value, Measurements, Recurring [Member] | AUGMENT Bone Graft Payment of Conditional Value Rights, Condition Two [Member]
Derivatives, Fair Value [Line Items]
Contingent Consideration Fair Value				$ 70,000									$ 70,000

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 534,366	$ 448,921
Less: Accumulated depreciation	(309,437)	(236,542)
Property, plant and equipment, net	224,929	212,379
Depreciation	59,500	56,800	$ 55,800
Land and land improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	2,127	2,163
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	43,087	41,537
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	82,445	60,859
Furniture, fixtures and office equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	161,614	142,299
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	14,113	14,403
Surgical instruments [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 230,980	$ 187,660

Property, Plant and Equipment -

Property, Plant and Equipment - Capital Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Capital Leased Assets [Line Items]
Depreciation	$ 59,500	$ 56,800	$ 55,800
Capital leased property, plant and equipment, gross	36,907	28,968
Less: Accumulated depreciation	(11,906)	(7,749)
Capital leased property, plant and equipment, net	25,001	21,219
Buildings [Member]
Capital Leased Assets [Line Items]
Capital leased property, plant and equipment, gross	12,017	15,530
Machinery and equipment [Member]
Capital Leased Assets [Line Items]
Capital leased property, plant and equipment, gross	24,331	12,478
Furniture, fixtures and office equipment [Member]
Capital Leased Assets [Line Items]
Capital leased property, plant and equipment, gross	$ 559	$ 960

Goodwill and Intangibles (Detai

Goodwill and Intangibles (Details) - USD ($) $ in Thousands	Dec. 14, 2017	Dec. 30, 2018	Dec. 31, 2017	Oct. 10, 2018
Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill, Purchase Accounting Adjustments		$ (917)	$ 71,981
Goodwill, Acquired During Period		351,445
Total intangibles		385,074	310,829
Less: Accumulated amortization		102,742	79,828
Intangible assets, net		282,332	231,001
Goodwill [Roll Forward]
Goodwill at December 31, 2012		933,662	851,042
Foreign currency translation		(15,236)	10,639
Goodwill at December 31, 2013		1,268,954	933,662
Future amortization [Abstract]
2,019		30,200
2,020		29,500
2,021		29,300
2,022		29,300
2,023		29,200
Finite-Lived Intangible Assets [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		378,812	304,407
Less: Accumulated amortization		102,742	79,828
Finite-Lived Intangible Assets [Member] | Distribution channels [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		250	900
Less: Accumulated amortization		250	640
Finite-Lived Intangible Assets [Member] | Completed technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		174,596	149,645
Less: Accumulated amortization		55,114	40,810
Finite-Lived Intangible Assets [Member] | Licenses [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		6,547	5,268
Less: Accumulated amortization		1,851	1,530
Finite-Lived Intangible Assets [Member] | Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		179,605	129,693
Less: Accumulated amortization		30,935	23,268
Finite-Lived Intangible Assets [Member] | Trademarks [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		14,048	14,368
Less: Accumulated amortization		11,564	10,487
Finite-Lived Intangible Assets [Member] | Noncompete Agreements [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		3,252	3,964
Less: Accumulated amortization		2,514	2,603
Finite-Lived Intangible Assets [Member] | Other [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Definite life intangibles, Cost		514	569
Less: Accumulated amortization		514	490
Indefinite-Lived Intangible Assets [Member] | Completed technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Indefinite life intangibles		6,262	6,422
IMASCAP SAS [Member]
Goodwill [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 10,900
Cartiva, Inc. [Member]
Goodwill [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 81,000
Cartiva, Inc. [Member] | Finite-Lived Intangible Assets [Member] | Customer Relationships [Member]
Goodwill [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 52,000
Lower Extremities & Biologics [Member] | UNITED STATES
Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill, Purchase Accounting Adjustments		0
Goodwill [Roll Forward]
Goodwill at December 31, 2012		218,525	218,525
Foreign currency translation		0
Goodwill at December 31, 2013		569,970	218,525
Lower Extremities & Biologics [Member] | UNITED STATES | Cartiva, Inc. [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period		351,445
Upper Extremities [Member] | UNITED STATES
Goodwill [Roll Forward]
Goodwill at December 31, 2012		630,650	558,669
Foreign currency translation		(1,883)
Goodwill at December 31, 2013		627,850	630,650
Upper Extremities [Member] | UNITED STATES | IMASCAP SAS [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill, Purchase Accounting Adjustments		(900)
Goodwill, Acquired During Period	$ 71,064		71,981
International Segment [Member] | Extremities & Biologics [Member]
Goodwill [Roll Forward]
Goodwill at December 31, 2012		84,487	73,848
Foreign currency translation		(13,353)	10,639
Goodwill at December 31, 2013		$ 71,134	$ 84,487

Goodwill and Intangibles Narrat

Goodwill and Intangibles Narrative (Details) (Details) - USD ($) $ in Thousands	Oct. 10, 2018	Dec. 14, 2017	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 1,268,954	$ 933,662	$ 851,042
Goodwill, Purchase Accounting Adjustments			(917)	71,981
Goodwill, Acquired During Period			351,445
Cartiva, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 81,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	(3,622)
Cartiva, Inc. [Member] | Finite-Lived Intangible Assets [Member] | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 52,000
IMASCAP SAS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 10,900
Contingent Consideration Fair Value		17,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		(2,343)
UNITED STATES | Lower Extremities & Biologics [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			569,970	218,525	218,525
Goodwill, Purchase Accounting Adjustments			0
UNITED STATES | Lower Extremities & Biologics [Member] | Cartiva, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period			351,445
UNITED STATES | Upper Extremities [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			627,850	630,650	558,669
UNITED STATES | Upper Extremities [Member] | IMASCAP SAS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Purchase Accounting Adjustments			(900)
Goodwill, Acquired During Period		71,064		71,981
International Segment [Member] | Extremities & Biologics [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 71,134	$ 84,487	$ 73,848
Customer Relationships [Member] | Cartiva, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Technology-Based Intangible Assets [Member] | Cartiva, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 28,000
Finite-Lived Intangible Asset, Useful Life	7 years
Technology-Based Intangible Assets [Member] | IMASCAP SAS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 5,600
Finite-Lived Intangible Asset, Useful Life		6 years
In Process Research and Development [Member] | Cartiva, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 1,000
In Process Research and Development [Member] | IMASCAP SAS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 5,300

Long-Term Debt and Capital Le_3

Long-Term Debt and Capital Lease Obligations (Details) $ / shares in Units, shares in Millions		Feb. 24, 2019USD ($)$ / sharesshares	Jun. 28, 2018USD ($)counterparty$ / shares	May 20, 2016USD ($)$ / shares	Nov. 24, 2015$ / shares	Feb. 13, 2015USD ($)$ / sharesshares	Aug. 31, 2008	May 31, 2018USD ($)	Dec. 30, 2018USD ($)shares	Sep. 30, 2018USD ($)	Jul. 01, 2018USD ($)	Apr. 01, 2018USD ($)	Jun. 25, 2017USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2018	Sep. 25, 2016	Dec. 30, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 25, 2016USD ($)shares	Dec. 31, 2012USD ($)	Oct. 01, 2015$ / shares	Sep. 30, 2015$ / shares	Sep. 30, 2012USD ($)	Aug. 31, 2012USD ($)$ / shares
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									$ 1,115,127,000								$ 1,115,127,000	$ 895,114,000
Debt Issuance Costs, Line of Credit Arrangements, Gross									$ 1,700,000								$ 1,700,000	2,200,000
Debt Instrument, Description of Variable Rate Basis								0.01									0.0075
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage																	0.50%
Line of Credit Facility, Minimum Borrowing Capacity as Percentage of Available Borrowing Capacity									20.00%								20.00%
Line of Credit, Prepayment Penalty								1.00%
Less: current portion	[1],[2]								$ (201,686,000)								$ (201,686,000)	(58,906,000)
Long-term debt and capital lease obligations	[2]								$ 913,441,000								913,441,000	836,208,000
Extinguishment of debt, amount																	400,911,000	0	$ 102,974,000
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees																	$ 39,935,000	0	12,343,000
ThresholdForConversionAsPercentOfConversionPrice									130.00%						130.00%		130.00%
wmgi_ThresholdForConversion																	98.00%
Debt Instrument, Convertible, Minimum Consecutive Period									20 days						20 days		20 days
Debt Instrument, Convertible, Trading Period									30 days						30 days		30 days
Debt instrument, convertible, purchase price as a percent of principal amount if fundamental change event occurs																	100.00%
Maturities of Long-term Obligations [Abstract]
2,014									$ 190,597,000								$ 190,597,000
2,015									2,125,000								2,125,000
2,016									416,463,000								416,463,000
2,017									935,000								935,000
2,018									675,042,000								675,042,000
Long term debt principal repayment due thereafter									1,380,000								1,380,000
Long-term Debt									1,286,542,000								1,286,542,000
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
2,014									7,369,000								7,369,000
2,015									6,106,000								6,106,000
2,016									4,545,000								4,545,000
2,017									3,553,000								3,553,000
2,018									2,430,000								2,430,000
LongTermDebtMaturitiesRepaymentsOfPrincipalThereafter									4,682,000								4,682,000
Total minimum payments									28,685,000								28,685,000
Less amount representing interest									3,146,000								3,146,000
Present value of minimum lease payments									25,539,000								25,539,000
Current portion									6,384,000								6,384,000
Long-term portion									19,155,000								19,155,000
Debt Discount at Time of Issuance																								$ 48,100,000
Amortization of Debt Discount (Premium)									12,600,000	$ 12,300,000	$ 12,300,000	$ 12,000,000
Line of Credit Facility, Maximum Borrowing Capacity									150,000,000								150,000,000
Repayments of Debt						$ 292,000,000
Payments for Repurchase of Warrants																	23,972,000	0	3,319,000
Proceeds from Hedge, Financing Activities																	34,553,000	0	3,892,000
Payments for (Proceeds from) Hedge, Financing Activities																				$ 56,200,000
Proceeds from Issuance of Warrants																	102,137,000	0	54,629,000
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Prepayment Speed								100.00%
Proceeds from Collaborators								$ 10,000,000
Term Loan [Member]
Debt and Capital Lease Obligations [Abstract]
Debt Issuance Costs, Net									1,000,000								1,000,000
Maturities of Long-term Obligations [Abstract]
Long-term Debt									20,000,000								20,000,000
2023 Convertible Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 675,000,000						675,000,000								675,000,000
Debt Conversion, Converted Instrument, Amount Delivered			$ 1,138.70
Interest and Debt Expense																	1,100,000
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									548,076,000								548,076,000
Stated percentage rate			1.625%
Debt instrument, convertible, conversion ratio			29.9679
Debt Instrument, Convertible, Conversion Price | $ / shares			$ 33.37
Debt Instrument, Convertible, Trading Period			120 days
Debt Issuance Costs, Net			$ 13,500,000
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Amortization of Debt Discount (Premium)																	10,100,000
Long-term Debt, Fair Value									$ 680,300,000								$ 680,300,000
Number of Counterparties | counterparty			2
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares									20.2								20.2
Debt Instrument, Unamortized Discount									$ (114,554,000)								$ (114,554,000)
Proceeds from Issuance of Warrants			$ 102,100,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares			$ 40.86
Unamortized Debt Issuance Expense									(12,370,000)								(12,370,000)
2023 Note Hedges [Member]
Debt Instrument [Line Items]
Indebtedness in Excess, Default			$ 25,000,000
2021 Convertible Debt [Member]
Debt Instrument [Line Items]
Interest and Debt Expense																	1,300,000	1,100,000	600,000
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									$ 321,286,000								321,286,000	300,051,000
Stated percentage rate				2.25%
Maturity date																Nov. 15, 2021
Debt instrument, convertible, conversion ratio																46.8165
Debt Instrument, Convertible, Conversion Price | $ / shares				$ 21.36
ThresholdForConversionAsPercentOfConversionPrice																130.00%
Debt Instrument, Convertible, Minimum Consecutive Period				20 days
Debt Instrument, Convertible, Trading Period				30 days
Debt instrument, convertible, purchase price as a percent of principal amount if fundamental change event occurs																100.00%
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Amortization of Debt Discount (Premium)																	$ 20,000,000	$ 18,100,000	9,800,000
Debt Instrument, Interest Rate, Effective Percentage									9.72%								9.72%
Long-term Debt, Fair Value									$ 533,400,000								$ 533,400,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares									18.5								18.5	18.5
Debt Instrument, Unamortized Discount				$ (117,200,000)					$ (69,382,000)								$ (69,382,000)	$ (89,332,000)
Proceeds from Issuance of Warrants				$ 54,600,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 30
Unamortized Debt Issuance Expense				$ (7,300,000)					4,332,000								4,332,000	5,617,000
Capital Lease Obligations [Member]
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									25,539,000								25,539,000	20,401,000
2017 Convertible Debt [Member]
Debt Instrument [Line Items]
Interest and Debt Expense																			200,000
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									18,979,000								$ 18,979,000	0
Stated percentage rate																								2.00%
Maturity date																	Aug. 15, 2017
Debt instrument, deferred financing charges																							$ 8,800,000
Debt instrument, convertible, conversion ratio							39.3140
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 25.44
ThresholdForConversionAsPercentOfConversionPrice							130.00%
wmgi_ThresholdForConversion							98.00%
Debt Instrument, Convertible, Minimum Consecutive Period							20 days
Debt Instrument, Convertible, Trading Period							30 days
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Amortization of Debt Discount (Premium)																			900,000
Debt Instrument, Interest Rate, Effective Percentage																							6.47%
Extinguishment of Debt, Amount																		54,400,000
Repayments of Debt																		56,300,000
Payments for Repurchase of Warrants														$ 60,000,000					60,000,000
Line of Credit [Member]
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									17,761,000								$ 17,761,000	53,645,000
2020 convertibledebt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount			400,900,000
Interest and Debt Expense																	2,300,000	3,300,000	3,100,000
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations	[1]								$ 173,533,000								$ 173,533,000	513,014,000
Stated percentage rate						2.00%
Maturity date																	Feb. 15, 2020
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees			39,900,000								$ 39,900,000		$ 9,300,000
Debt instrument, deferred financing charges						$ 18,100,000
Debt instrument, convertible, conversion ratio					33.39487												32.3939
Debt Instrument, Convertible, Conversion Price | $ / shares					$ 29.94																	$ 30.87
ThresholdForConversionAsPercentOfConversionPrice																	130.00%
Debt Instrument, Convertible, Minimum Consecutive Period																	20 days
Debt Instrument, Convertible, Trading Period																	30 days
Debt instrument, convertible, purchase price as a percent of principal amount if fundamental change event occurs																	100.00%
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Amortization of Debt Discount (Premium)																	$ 19,100,000	$ 27,300,000	$ 25,900,000
Debt Instrument, Interest Rate, Effective Percentage						8.54%
Extinguishment of Debt, Amount													$ 45,000,000				45,000,000
Repayments of Debt																	$ 44,600,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares						21.1			6.2								6.2	19.6	19.6
Payments for Repurchase of Warrants				3,300,000
Proceeds from Hedge, Financing Activities				600,000
Debt Instrument, Unamortized Discount									$ (11,642,000)								$ (11,642,000)	$ (66,418,000)
Incremental Common Shares Attributable to Call Options and Warrants | shares						20.5
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares						$ 40															$ 38.8010
Unamortized Debt Issuance Expense									1,414,000								1,414,000	8,068,000
Other Debt Obligations [Member]
Debt and Capital Lease Obligations [Abstract]
Debt and capital lease obligations									$ 9,953,000								$ 9,953,000	8,003,000
Minimum [Member]
Debt and Capital Lease Obligations [Abstract]
Line of Credit, Prepayment Penalty									0.75%								0.75%
Maximum [Member] | Line of Credit [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity									$ 100,000,000								$ 100,000,000
2020 Conversion Derivative [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Derivative, Cash Received on Hedge				3,900,000
Debt Instrument, Unamortized Discount						$ (149,800,000)
2017 Notes Conversion Derivative [Member]
Debt and Capital Lease Obligations [Abstract]
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees																		3,000,000	$ 25,100,000
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Debt Discount at Time of Issuance																								$ 48,100,000
Repayments of Debt														240,000,000				3,600,000	240,000,000
Derivative, Cash Received on Hedge														$ 70,000,000					$ 70,000,000
Reported Value Measurement [Member] | 2021 Convertible Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross				395,000,000					395,000,000								395,000,000	395,000,000
Reported Value Measurement [Member] | 2017 Convertible Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross																								$ 300,000,000
Reported Value Measurement [Member] | 2020 convertibledebt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						$ 632,500,000			186,589,000								186,589,000	$ 587,500,000
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Long-term Debt, Fair Value									$ 196,900,000								$ 196,900,000
2021 Convertible Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Derivative, Cost of Hedge				99,800,000
Base Rate [Member]
Debt and Capital Lease Obligations [Abstract]
Line of Credit Facility, Interest Rate at Period End									3.25%								3.25%
Variable Income Interest Rate [Member]
Debt and Capital Lease Obligations [Abstract]
Line of Credit Facility, Interest Rate at Period End								8.00%	4.25%								4.25%
Subsequent Event [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity		$ 175,000,000
Subsequent Event [Member] | 2023 Convertible Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		814,600,000
Subsequent Event [Member] | 2020 convertibledebt [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		56,500,000
Debt Conversion, Converted Instrument, Amount		$ 130,100,000
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares		1.9
Subsequent Event [Member] | Additional 2023 Convertible Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 139,600,000
Debt and Capital Lease Obligations [Abstract]
Debt Instrument, Convertible, Conversion Price | $ / shares		$ 33.37
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares		4.2
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares		$ 40.86
Subsequent Event [Member] | Maximum [Member] | Line of Credit [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity		$ 75,000,000
Circumstance 2 [Domain]
Debt and Capital Lease Obligations [Abstract]
Debt Instrument, Convertible, Minimum Consecutive Period																	5 days
2023 Conversion Derivative [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Long-term Debt, Fair Value			$ 124,600,000
2023 Note Hedges [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Number of Counterparties | counterparty			2
Derivative, Cost of Hedge			$ 141,300,000
2017 Convertible Debt [Member] | 2021 Convertible Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Extinguishment Of Debt, Amount Delivered Per Incremental Amount Exchanged				1,035.40
2020 convertibledebt [Member] | 2021 Convertible Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Extinguishment Of Debt, Amount Delivered Per Incremental Amount Exchanged				$ 990
2020 convertibledebt [Member] | Subsequent Event [Member] | 2023 Convertible Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Extinguishment Of Debt, Amount Delivered Per Incremental Amount Exchanged		1,072.40
Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity								$ 40,000,000
Debt Instrument, Term								2 years
Debt Instrument, Tranche 1 [Member] | Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity								$ 20,000,000
Debt Instrument, Tranche 2 [Member] | Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity								$ 20,000,000
Debt Instrument, Tranche 2 [Member] | Line of Credit [Member] | Term Loan [Member] | Subsequent Event [Member] | Secured Debt [Member]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity		$ 35,000,000
[1]	1 The holders of the 2020 Notes may convert their notes at any time prior to August 15, 2019 solely into cash upon satisfaction of certain circumstances as described below. On or after August 15, 2019, holders may convert their 2020 Notes solely into cash, regardless of the foregoing circumstances. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes were classified as current liabilities as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017.
[2]	1 The holders of the 2020 Notes will have the ability to begin converting their 2020 Notes beginning August 15, 2019 through their maturity. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes and the fair value of the 2020 Notes Conversion Derivative were classified as current liabilities, and the fair value of the 2020 Notes Hedges was classified as current assets as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017. See Note 6 and Note 9.

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity Attributable to Parent	$ 932,459	$ 588,696	$ 686,864	$ 1,055,026	[1]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(8,083)	22,290
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(30,373)	41,751	(8,977)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity Attributable to Parent	(8,083)	22,290	(19,461)
Accumulated Other Comprehensive Income (Loss) [Member] | Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity Attributable to Parent				$ (10,484)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(8,083)	22,290	(19,461)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ (30,373)	$ 41,751	$ (8,977)
[1]	During 2015, the 2014 balances of ordinary shares and additional paid in capital were restated to meet post-merger conversion values.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Operating Loss Carryforwards [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 33,000
Unrecognized Tax Benefits	4,610	$ 6,025	$ 8,095
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1,000
Components of income before income taxes [Abstract]
U.S.	(144,987)	(56,808)	(140,190)
Foreign	(24,853)	(43,097)	(38,150)
Income (loss) before income taxes	(169,840)	(99,905)	(178,340)
Current provision (benefit):
Federal	449	(23,781)	(1,971)
State	251	390	(281)
Foreign	3,307	2,214	3,860
Total current provision	4,007	(21,177)	1,608
Deferred (benefit) provision:
Federal	(2,841)	(5,098)	1,244
State	(663)	(93)	142
Foreign	(1,039)	(8,600)	(16,400)
Total deferred (benefit) provision	(4,543)	(13,791)	(15,014)
Total provision for income taxes	$ (536)	$ (34,968)	$ (13,406)
Reconciliation of statutory U.S. federal income tax rate to effective income tax rate [Abstract]
Income tax provision at statutory rate	21.00%	35.00%	35.00%
State income taxes	3.80%	1.50%	2.90%
Change in valuation allowance	(22.90%)	(3.50%)	(32.60%)
Deferred Tax Write Off	0.00%	(1.90%)	(1.70%)
Effective Income Tax Rate Reconciliation, Foreign Income Taxes, Percent	(0.60%)	(6.10%)	3.30%
Effective Income Tax Rate Reconciliation, Change in Reserves, Percent	0.40%	2.90%	0.80%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	0.00%	6.50%	0.00%
Effective Income Tax Rate Reconciliation, Tax Contingency, Foreign, Percent		1.70%
Other, net	(1.40%)	(1.10%)	(0.20%)
Total	0.30%	35.00%	7.50%
Deferred Tax Assets:
Net operating loss carryforwards	$ 330,589	$ 283,708
General business credit carryforward	14,598	12,993
Reserves and allowances	56,675	90,246
Stock-based compensation expense	14,934	13,679
Other	3,616	1,642
Convertible debt notes and conversion option	38,368	10,747
Valuation allowance	(400,171)	(366,825)
Total deferred tax assets	85,931	46,190
Deferred Tax Liabilities:
Depreciation	5,095	6,383
Intangible assets	58,221	42,862
Deferred Tax Liabilities, Derivatives	34,653	11,668
Other	166	120
Total deferred tax liabilities	98,135	61,033
Net deferred tax assets	(12,204)	$ (14,843)
Foreign operating loss - do not expire [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	77,000
Foreign operating losses that will expire [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	86,000
US Federal Operating Loss [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,100,000
US Federal Operating Loss - do not expire [Domain]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	150,000
US Federal Operating Loss -expiring [Domain]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	965,000
US Federal Operating Loss -expiring in 5 years [Domain]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	15,000
US State Operating loss [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,200,000
US State Operating loss - do not expire [Domain]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	25,000
US State Operating loss - expiring [Domain]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,160,000
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	15,000
Foreign Operating Loss [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	163,000
Cartiva, Inc. [Member]
Deferred Tax Assets:
Valuation allowance	$ (3,600)

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Income Tax Contingency [Line Items]
Deferred Tax Assets, Other	$ 3,616	$ 1,642
Deferred Tax Liabilities, Derivatives	$ 34,653	$ 11,668
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%	35.00%
Income Tax Expense (Benefit)	$ 33,000
Unrecognized Tax Benefits, Period Increase (Decrease)	109
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	200
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	1,000
Unrecognized Tax Benefits [Roll Forward]
Balance at January 1, 2013	6,025	$ 8,095
Additions for tax positions related to current year	385	215
Additions for tax positions of prior years	718	20
Reductions for tax positions of prior years	490	3,174
Settlements	1,983	0
Foreign currency translation	(154)	869
Balance at December 31, 2013	4,610	6,025	$ 8,095
Income Tax Expense (Benefit)	(536)	$ (34,968)	$ (13,406)
Revaluation of net deferred tax liabilities and reduction of valuation allowance [Member]
Unrecognized Tax Benefits [Roll Forward]
Income Tax Expense (Benefit)	$ 6,600

Income Taxes - Tax Credit Carry

Income Taxes - Tax Credit Carryforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	$ 330,589	$ 283,708
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	33,000
General business credit carryforward	14,598	12,993
Reserves and allowances	56,675	90,246
DeferredTaxAssetsDeferredInterest	27,322
Share-based compensation expense	14,934	13,679
DeferredTaxAssetsconvertibledebtandderivative	38,368	10,747
Deferred Tax Assets, Other	3,616	1,642
Valuation allowance	400,171	366,825
Total deferred tax assets	85,931	46,190
Depreciation	5,095	6,383
Intangible assets	58,221	42,862
Deferred Tax Liabilities, Derivatives	34,653	11,668
Other	166	120
Total deferred tax liabilities	98,135	61,033
Net deferred tax liabilities	(12,204)	$ (14,843)
US Federal Operating Loss [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	1,100,000
US State Operating loss [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	1,200,000
General Business [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	15,000
Foreign Operating Loss [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	$ 163,000

Other Balance Sheet Informati_3

Other Balance Sheet Information (Details) - USD ($) $ in Thousands		Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Other Long-Term Liabilities [Abstract]
Accrued Bonuses, Current		$ 28,953	$ 12,803
Unrecognized tax benefits (See Note 14)		4,610	6,025	$ 8,095
Product liability (see Note 19)		30,755	60,711
Derivative Liability, Fair Value, Gross Liability		304,372	170,280
Derivative Liability, Fair Value, Gross Liability		17,386
Contingent Consideration, noncurrent		15,821	18,301
Other		17,281	23,453
Other liabilities	[1]	368,229	272,745
Other Employee Related Liabilities, Current		22,841	22,401
Accrued Royalties, Current		12,330	12,563
Accrual for Taxes Other than Income Taxes, Current		7,897	8,933
Accrued Sales Commission, Current		19,356	19,330
Accrued Professional Fees, Current		10,848	12,388
Contingent Consideration Fair Value, Current		3,427	1,168
Product Liability Accrual, Current		66,918	151,027
Current Portion of CVR Contingent Consideration Liability		420	42,044
Other Accrued Liabilities, Current		26,705	31,901
Accrued Expenses And Other Current Liabilities	[1]	$ 217,081	$ 314,558
[1]	1 The holders of the 2020 Notes will have the ability to begin converting their 2020 Notes beginning August 15, 2019 through their maturity. Due to the ability of the holders of the 2020 Notes to convert within the next year, the carrying value of the 2020 Notes and the fair value of the 2020 Notes Conversion Derivative were classified as current liabilities, and the fair value of the 2020 Notes Hedges was classified as current assets as of December 30, 2018. The respective balances were classified as long-term as of December 31, 2017. See Note 6 and Note 9.

Earnings per share (Details)

Earnings per share (Details) - shares shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016	Feb. 13, 2015
Antidilutive securities, non-vested shares, performance shares	200				100				200	100
Weighted Average Number of Shares Outstanding, Basic and Diluted	125,323	113,043	106,095	105,904	105,195	104,836	104,377	103,663	112,592	104,531	102,968
Weighted-average number of shares outstanding, diluted					106,578	104,836	104,377	103,663
Non-vested shares, restricted stock units, and stock-settled phantom stock units									1,300	1,300	1,300
2020 convertibledebt [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	6,200				19,600				6,200	19,600	19,600	21,100
2021 Convertible Debt [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	18,500				18,500				18,500	18,500
2023 Convertible Debt [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	20,200								20,200

Capital Stock and Earnings per

Capital Stock and Earnings per share Capital Stock (Details) $ / shares in Units, $ in Thousands	Aug. 27, 2018USD ($)$ / sharesshares	Dec. 30, 2018USD ($)$ / sharesshares	Dec. 31, 2017$ / sharesshares	Dec. 25, 2016shares	Dec. 30, 2018€ / sharesshares	Feb. 13, 2015shares
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		9,900,000	10,000,000	10,400,000
Antidilutive Securities Stock Options		1,300,000	1,300,000	1,300,000
Antidilutive securities, non-vested shares, performance shares		200,000	100,000		200,000
Common stock, shares authorized (in shares)		320,000,000	320,000,000		320,000,000
Common Stock, Par or Stated Value Per Share | (per share)		$ 0.03	$ 0.03		€ 0.03
Common Stock, Shares, Issued		125,555,751	105,807,424		125,555,751
Shares Issued, Price Per Share | $ / shares	$ 24.60
Stock Issued | $	$ 448,900
Proceeds from Issuance or Sale of Equity | $		$ 448,924
Payments of Stock Issuance Costs | $	$ 500	$ 25,896
Common Stock [Member]
Stock Issued During Period, Shares, Other	18,200,000	18,248,932
Sale of Stock [Domain]
Proceeds from Issuance or Sale of Equity | $	$ 423,000
2020 convertibledebt [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		6,200,000	19,600,000	19,600,000	6,200,000	21,100,000
Discount and Commissions [Member]
Payments of Stock Issuance Costs | $	$ 25,400

Share-Based Compensation (Detai

Share-Based Compensation (Details) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 30, 2018USD ($)periods$ / sharesshares	Sep. 30, 2018shares	Jul. 01, 2018shares	Apr. 01, 2018$ / sharesshares	Dec. 31, 2017$ / sharesshares	Sep. 24, 2017shares	Jun. 25, 2017shares	Mar. 26, 2017shares	Dec. 30, 2018USD ($)periods$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 25, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price		$ 26.51								$ 26.51
Amounts Recognized in the consolidated financial statements
Total cost of share-based payment plans | $										$ 26,039	$ 19,485	$ 14,406
Amounts capitalized as inventory and intangible assets | $										(507)	(669)	(416)
Amortization of capitalized amounts | $										588	577	426
Impact to net income (loss) | $										$ 26,120	$ 19,393	$ 14,416
Impact to basic earnings per share										$ 0.23	$ 0.19	$ 0.14
Weighted Average Number of Shares Outstanding, Basic and Diluted | shares		125,323,000	113,043,000	106,095,000	105,904,000	105,195,000	104,836,000	104,377,000	103,663,000	112,592,000	104,531,000	102,968,000
Summary of stock option activity
Employee Stock Ownership Plan (ESOP), Shares in ESOP | shares		216,227								216,227
Narrative
Nonvested Awards, Total Compensation Cost Not yet Recognized | $		$ 48,000								$ 48,000
Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition										2 years 6 months 25 days
Number of Shares Authorized | shares		5,000,000								5,000,000
Expiration Term										10 years
Number of Shares Available for Grant | shares		2,297,162								2,297,162
Shares, Outstanding | shares		11,451,090								11,451,090
Options, Exercises in Period, Total Intrinsic Value | $										$ 4,900	$ 9,100	$ 2,100
Employee Stock Purchase Plan, Number of Plan Periods During Each Year | periods		2								2
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent										20.00%
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares | shares		1,000								1,000
Percent of Market Value at Lower of Beginning or Ending Period Market Price , Purchase Date										85.00%
Award Requisite Service Period										4 years
Restricted Stock Units (RSUs) [Member]
Amounts Recognized in the consolidated financial statements
Total cost of share-based payment plans | $										$ 11,514	$ 9,373	$ 8,416
Nonvested Shares Roll Forward
Nonvested Shares, Beginning Balance | shares					1,280,000					1,280,000
Granted | shares										607,000	500,000	700,000
Vested | shares										(460,000)
Forfeited | shares										(105,000)
Nonvested Shares, Ending Balance | shares		1,322,000				1,280,000				1,322,000	1,280,000
Nonvested, Weighted-Average Grant-Date Fair Value, Beginning Balance					$ 23.45					$ 23.45
Granted										24.05	$ 27.83	$ 21.17
Vested										22.89
Forfeited										23.63
Nonvested, Weighted-Average Grant-Date Fair Value, Ending Balance		$ 23.90				$ 23.45				23.90	$ 23.45
Aggregate Intrinsic Value	[1]	$ 35,052,000								$ 35,052,000
Narrative
Equity Instruments Other than Options, Vested in Period, Total Fair Value | $										$ 12,200	$ 9,000	$ 7,000
Restricted Stock Units (RSUs) [Member] | Director [Member]
Narrative
Award Requisite Service Period										1 year
Inducement Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price										$ 19.71
Summary of stock option activity
Options Outstanding, Beginning Balance | shares					875,000					875,000
Exercised | shares										(182,000)
Options Outstanding, Ending Balance | shares		693,000				875,000				693,000	875,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price		$ 15.66								$ 15.66
Outstanding, Weighted-Average Exercise Price, Ending Balance		$ 15.66								$ 15.66
Outstanding, Weighted-Average Remaining Contractual Life										2 years 8 months 26 days
Exercisable, Weighted-Average Remaining Contractual Life										2 years 8 months 26 days
Outstanding, Aggregate Intrinsic Value | $	[2]	$ 7,522								$ 7,522
Exercisable, Aggregate Intrinsic Value | $		693								$ 693
Nonvested Shares Roll Forward
Nonvested, Weighted-Average Grant-Date Fair Value, Beginning Balance					$ 16.50					$ 16.50
Nonvested, Weighted-Average Grant-Date Fair Value, Ending Balance						$ 16.50					$ 16.50
Narrative
Options, Exercises in Period, Total Intrinsic Value | $										$ 1,600	$ 300	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value | $	[2]	$ 7,522								$ 7,522
Inducement Grant [Member] | Share Based Compensation, Exercise Price Range 1 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit										$ 15
Exercise Price Range, Upper Range Limit										$ 18
Number Outstanding | shares		693,000								693,000
Weighted-Average Remaining Contractual Life										2 years 8 months 26 days
Weighted-Average Exercise Price		$ 15.66								$ 15.66
Number Exercisable | shares		693,000								693,000
Weighted-Average Exercise Price		$ 15.66								$ 15.66
Inducement Grant [Member] | Share Based Compensation, Exercise Price Range 2 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit
Exercise Price Range, Upper Range Limit
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price										$ 21.18
Amounts Recognized in the consolidated financial statements
Total cost of share-based payment plans | $										$ 11,177	$ 8,988	$ 5,844
Fair Value Assumptions
Fair Value Assumptions, Risk Free Interest Rate, Minimum										2.60%	1.90%	1.10%
Fair Value Assumptions, Risk Free Interest Rate, Maximum										2.90%	2.00%	1.40%
Fair Value Assumptions, Expected Term										7 years	6 years	6 years
Fair Value Assumptions, Expected Volatility Rate										32.00%	33.00%	34.00%
Summary of stock option activity
Options Outstanding, Beginning Balance | shares					9,114,000					9,114,000
Granted | shares										1,464,000
Exercised | shares										(750,000)
Forfeited or expired | shares										(625,000)
Options Outstanding, Ending Balance | shares		9,203,000				9,114,000				9,203,000	9,114,000
Exercisable at December 31, 2013 | shares		6,086,000								6,086,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price		$ 22.30								$ 22.30
Granted, Weighted-Average Exercise Price										24.14
Outstanding, Weighted-Average Exercise Price, Ending Balance		$ 22.89				$ 22.73				$ 22.89	$ 22.73
Outstanding, Weighted-Average Remaining Contractual Life										6 years 6 months 6 days
Exercisable, Weighted-Average Remaining Contractual Life										5 years 5 months 15 days
Outstanding, Aggregate Intrinsic Value | $	[3]	$ 36,809								$ 36,809
Exercisable, Aggregate Intrinsic Value | $	[3]	$ 28,127								$ 28,127
Summary of stock options outstanding and exercisable
Number Outstanding | shares		9,203,000								9,203,000
Weighted-Average Remaining Contractual Life										6 years 6 months 7 days
Weighted-Average Exercise Price		$ 22.89								$ 22.89
Number Exercisable | shares		6,086,000								6,086,000
Weighted-Average Exercise Price		$ 22.30								$ 22.30
Narrative
Options, Grants in Period, Weighted Average Grant Date Fair Value										9.32	$ 9.80	$ 7.36
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price										$ 25.51
Stock Options [Member] | Director [Member]
Narrative
Award Requisite Service Period										2 years
Stock Options [Member] | Share Based Compensation, Exercise Price Range 1 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit										$ 2
Exercise Price Range, Upper Range Limit										$ 20
Number Outstanding | shares		1,078,000								1,078,000
Weighted-Average Remaining Contractual Life										4 years 7 days
Weighted-Average Exercise Price		$ 17.66								$ 17.66
Number Exercisable | shares		976,000								976,000
Weighted-Average Exercise Price		$ 17.48								$ 17.48
Stock Options [Member] | Share Based Compensation, Exercise Price Range 2 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit										20.01
Exercise Price Range, Upper Range Limit										$ 21
Number Outstanding | shares		2,276,000								2,276,000
Weighted-Average Remaining Contractual Life										6 years 3 months 27 days
Weighted-Average Exercise Price		$ 20.64								$ 20.64
Number Exercisable | shares		1,835,000								1,835,000
Weighted-Average Exercise Price		$ 20.64								$ 20.64
Stock Options [Member] | Share Based Compensation, Exercise Price Range 3 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit										21.01
Exercise Price Range, Upper Range Limit										$ 25
Number Outstanding | shares		3,753,000								3,753,000
Weighted-Average Remaining Contractual Life										7 years 1 month 29 days
Weighted-Average Exercise Price		$ 22.85								$ 22.85
Number Exercisable | shares		1,945,000								1,945,000
Weighted-Average Exercise Price		$ 22.21								$ 22.21
Stock Options [Member] | Share Based Compensation, Exercise Price Range 4 [Member]
Summary of stock options outstanding and exercisable
Exercise Price Range, Lower Range Limit										25.01
Exercise Price Range, Upper Range Limit										$ 32
Number Outstanding | shares		2,096,000								2,096,000
Weighted-Average Remaining Contractual Life										6 years 10 months 13 days
Weighted-Average Exercise Price		$ 28.10								$ 28.10
Number Exercisable | shares		1,330,000								1,330,000
Weighted-Average Exercise Price		$ 28.27								$ 28.27
Employee Stock [Member]
Amounts Recognized in the consolidated financial statements
Total cost of share-based payment plans | $										$ 810	$ 683	$ 146
Fair Value Assumptions
Fair Value Assumptions, Risk Free Interest Rate, Minimum										2.30%	1.30%	1.20%
Fair Value Assumptions, Risk Free Interest Rate, Maximum										2.80%	1.90%	1.30%
Fair Value Assumptions, Expected Term										6 months	6 months	3 months
Fair Value Assumptions, Expected Volatility Rate										31.00%	24.00%	33.00%
Narrative
Number of Shares Authorized | shares		550,000								550,000
Number of Shares Available for Grant | shares		322,810								322,810
Performance Shares [Member]
Amounts Recognized in the consolidated financial statements
Total cost of share-based payment plans | $										$ 2,538	$ 441	$ 0
Nonvested Shares Roll Forward
Nonvested Shares, Beginning Balance | shares					108,000					108,000
Granted | shares										129,000	100,000
Vested | shares										0
Forfeited | shares										(4,000)
Nonvested Shares, Ending Balance | shares		233,000				108,000				233,000	108,000
Nonvested, Weighted-Average Grant-Date Fair Value, Beginning Balance					$ 27.86					$ 27.86
Granted										24.49	$ 27.86
Vested										0
Forfeited										27.86
Nonvested, Weighted-Average Grant-Date Fair Value, Ending Balance		$ 26				$ 27.86				26	$ 27.86
Aggregate Intrinsic Value	[1]	$ 6,176,000								$ 6,176,000
Narrative
Award Requisite Service Period										3 years
Minimum [Member]
Narrative
Award Requisite Service Period										3 years
Maximum [Member]
Narrative
Award Requisite Service Period										4 years
Share-based Compensation Arrangements by Share-based Payment Award, Performance-Based Units, Vested and Expected to Vest [Table Text Block]										2
Tornier N.V. [Member]
Summary of stock option activity
Employee Stock Ownership Plan (ESOP), Shares in ESOP | shares		333,333								333,333
Wright Medical Group, Inc. [Member]
Narrative
Expiration Term										10 years
Shares, Outstanding | shares		2,547,656								2,547,656
2010 Plan [Member]
Summary of stock option activity
Forfeited or expired | shares										6,405,992
Narrative
Number of Shares Available for Grant | shares		1,329,648								1,329,648
[1]	The aggregate intrinsic value is calculated as the market value of our ordinary shares as of December 30, 2018. The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018, the last trading day prior to December 30, 2018, as reported by the Nasdaq Global Select Market.
[2]	*The aggregate intrinsic value is calculated as the difference between the market value of our ordinary shares as of December 30, 2018 and the respective exercise prices of the options. The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018, the last trading day prior to December 30, 2018, as reported by the Nasdaq Global Select Market.
[3]	The aggregate intrinsic value is calculated as the difference between the market value of our ordinary shares as of December 30, 2018 and the respective exercise prices of the options. The market value as of December 30, 2018 was $26.51 per share, which is the closing sale price of our ordinary shares on December 28, 2018, the last trading day prior to December 30, 2018, as reported by the Nasdaq Global Select Market.

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Description	18
Employer matching contribution per employee on first 2% of employee's annual compensation	100.00%
Percentage of employee annual compensation eligible for 100% employer matching contribution	3.00%
Employer matching contribution per employee on second 2% of employee's annual compensatio	50.00%
Percentage of employee annual compensation eligible for 50% employer matching contribution	2.00%
Defined contribution plan expense	$ 6.2	$ 5.5	$ 4.9
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%

Commitments and Contingencies -

Commitments and Contingencies - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Commitments and Contingencies Disclosure [Abstract]
Rental expense under operating leases	$ 11,100	$ 8,900	$ 10,500
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,019	9,606
2,020	7,498
2,021	6,019
2,022	4,433
2,023	2,678
Thereafter	10,998
Total	$ 41,232

Commitments and Contingencies_2

Commitments and Contingencies - Commitments and Purchase Obligations (Details) $ in Millions	Dec. 30, 2018USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Purchase Obligation, Due in Second Year	$ 1.3
Purchase Obligation, Due in Third Year	1.3
Purchase Obligation, Due in Third Year	1.9
Capital Addition Purchase Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Purchase Obligation	$ 12

Commitments and Contingencies_3

Commitments and Contingencies - Product Liability Contingency (Details) - USD ($)

May 08, 2018

May 01, 2018

Apr. 19, 2018

Oct. 03, 2017

Sep. 01, 2015

Sep. 30, 2013

Jun. 30, 2013

Sep. 25, 2016

Dec. 30, 2018

Dec. 31, 2017

Dec. 25, 2016

Jan. 02, 2018

Jun. 25, 2017

Product Liability Contingency [Line Items]

Purchase Obligation, Due in Next Twelve Months

$ 1,900,000

2,019

9,606,000

Restricted Cash and Cash Equivalents, Current

$ 150,000,000

Payments for Legal Settlements

$ 1,800,000

Third Party Recovery

$ 10,000,000

$ 5,000,000

6,700,000

Loss Contingency, Receivable, Period Increase (Decrease)

(42,044,000)

0

0

2,020

7,498,000

2,021

6,019,000

2,022

4,433,000

2,023

2,678,000

Thereafter

10,998,000

Operating Leases, Future Minimum Payments Due

41,232,000

Insurance Recoveries

101,900,000

CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

74,500,000

PROFEMUR Titanium Modular Neck Product [Member]

Product Liability Contingency [Line Items]

Insurance Settlements Receivable, Current

$ 0

Allowance for Doubtful Accounts Receivable, Write-offs

25,000,000

Product liability, current

12,300,000

Product liability, non-current

5,200,000

Increase Decrease in Estimated Recovery from Third Party

$ 19,400,000

Loss Contingency, Receivable, Period Increase (Decrease)

$ 25,000,000

Master Settlement Agreement - MDL & JCCP [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

240,000,000

Accrual for eligible claims in excess of 1292 excluded from MSA [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

$ 9,400,000

Second Settlement Agreement [Member]

Product Liability Contingency [Line Items]

Percent Of Claimants Opted-In

100.00%

Second Settlement Agreement [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

82,700,000

Litigation Settlement, Amount (Deprecated 2017-01-31)

$ 89,750,000

Minimum [Member] | PROFEMUR Titanium Modular Neck Product [Member]

Product Liability Contingency [Line Items]

Estimated product liability range

17,500,000

Accrued Liabilities, Current [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

51,900,000

Other Noncurrent Liabilities [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Loss Contingency Accrual

22,600,000

Lexington [Member] | Metal-On-Metal Claims [Member]

Product Liability Contingency [Line Items]

Policy Limits Remaining

$ 30,000,000

Insurance Carrier [Member]

Product Liability Contingency [Line Items]

Proceeds from Legal Settlements

$ 30,750,000

Insurance Policy Limit

25,000,000

Insurance Policy, Costs And Interest Received

$ 5,750,000

Columbia [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Insurance Recoveries

$ 10,000,000

$ 60,000,000

Federal [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Insurance Recoveries

5,000,000

Insurance Settlements Receivable

15,000,000

Lloyd's Of London Syndicate 2003 [Member]

Product Liability Contingency [Line Items]

Proceeds from Legal Settlements

$ 1,900,000

$ 5,000,000

Catlin [Member] | Metal-On-Metal Claims [Member]

Product Liability Contingency [Line Items]

Policy Limits Remaining

$ 5,000,000

Loss Contingency, Settlement, Tranche 1 [Member] | Second Settlement Agreement [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Litigation Settlement, Amount (Deprecated 2017-01-31)

7,900,000

Loss Contingency, Settlement, Tranche 2 [Member] | Second Settlement Agreement [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Litigation Settlement, Amount (Deprecated 2017-01-31)

5,100,000

Loss Contingency, Settlement, Tranche 3 [Member] | Second Settlement Agreement [Member] | CONSERVE (R) DYNASTY (R) AND LINEAGE (R) [Member]

Product Liability Contingency [Line Items]

Litigation Settlement, Amount (Deprecated 2017-01-31)

76,750,000

Litigation Settlement, Amount, Net Of Insurance Deficit

45,000,000

Litigation Settlement, Amount, Insurance Deficit

$ 13,100,000

Restricted Cash (Details)

Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 191,351	$ 167,740	$ 262,300
Cash and Cash Equivalents, Fair Value Disclosure	$ 191,351	167,740
Restricted Cash and Cash Equivalents, Current		$ 150,000

Related Parties (Details)

Related Parties (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2018	Dec. 30, 2018
Related Party Transaction [Line Items]
Debt Instrument, Description of Variable Rate Basis	0.01	0.0075
Operating Leases, Future Minimum Payments Due		$ 41,232

Quarterly Results of Operatio_3

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jun. 28, 2018	May 08, 2018	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017	Jun. 30, 2013	Dec. 30, 2018		Dec. 31, 2017		Dec. 25, 2016
Quarterly Financial Information [Line Items]
Business Combination, Integration Related Costs			$ 7,800	$ 2,000	$ 1,300	$ 900
InventoryStepUpAmortizationExpenseContinuingOperations																$ 37,700
Income Tax Expense (Benefit)												$ (536)		$ (34,968)		(13,406)
Net sales			238,147	194,106	205,400	198,537	$ 217,602	$ 170,503	$ 179,693	$ 177,191		836,190		744,989		690,362
Cost of sales			49,149	44,307	45,558	41,139	47,278	38,421	38,122	37,126		180,153	[1],[2]	160,947	[1],[2]	192,407	[1],[2]
Gross profit			188,998	149,799	159,842	157,398	170,324	132,082	141,571	140,065		656,037		584,042		497,955
Operating expenses:
Selling, general and administrative			160,664	139,223	140,826	137,248	133,149	131,421	130,818	129,834		577,961	[2]	525,222	[2]	541,558	[2]
Research and development			16,749	13,829	14,665	13,899	13,144	11,992	12,547	12,432		59,142	[2]	50,115	[2]	50,514	[2]
Amortization of intangible assets			7,699	5,881	6,009	7,141	6,822	7,178	6,999	7,397		26,730		28,396		28,841	[3]
Total operating expenses			185,112	158,933	161,500	158,288	153,115	150,591	150,364	149,663		663,833		603,733		620,913
Operating income			3,886	(9,134)	(1,658)	(890)	17,209	(18,509)	(8,793)	(9,598)		(7,796)		(19,691)		(122,958)
Income (Loss) from Continuing Operations Attributable to Parent			(22,947)	(35,829)	(90,621)	(19,907)	26,852	(34,122)	(20,960)	(36,707)		(169,304)		(64,937)		(164,934)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			(10,821)	(6,696)	22,923	(5,607)	2,281	(97,748)	(20,202)	(21,992)		(201)		(137,661)		(267,439)
Net income (loss)			$ (33,768)	$ (42,525)	$ (67,698)	$ (25,514)	$ 29,133	$ (131,870)	$ (41,162)	$ (58,699)		$ (169,505)		$ (202,598)		$ (432,373)
Income (Loss) from Continuing Operations, Per Basic and Diluted Share			$ (0.18)	$ (0.32)	$ (0.85)	$ (0.19)						$ (1.50)		$ (0.62)		$ (1.60)
Income (Loss) from Continuing Operations, Per Basic Share							$ 0.26	$ (0.33)	$ (0.20)	$ (0.35)
Income (Loss) from Continuing Operations, Per Diluted Share							$ 0.25	$ (0.33)	$ (0.20)	$ (0.35)
Earnings Per Share, Basic and Diluted			$ (0.27)	$ (0.38)	$ (0.64)	$ (0.24)						$ (1.51)		$ (1.94)		$ (4.20)
Weighted Average Number of Shares Outstanding, Basic and Diluted			125,323	113,043	106,095	105,904	105,195	104,836	104,377	103,663		112,592		104,531		102,968
Net (loss) income per share, diluted							$ 0.27	$ (1.26)	$ (0.39)	$ (0.57)
Weighted Average Number of Shares Outstanding, Diluted							106,578	104,836	104,377	103,663
Management Changes																$ 1,348
Payments for Legal Settlements																1,800
Inventory write-down												$ 20,913		$ 19,171		22,046
Amortization of Debt Discount (Premium)			$ 12,600	$ 12,300	$ 12,300	$ 12,000
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees												39,935		0		12,343
Amortization of Financing Costs and Discounts							$ 11,700	$ 11,500	$ 11,200	$ 11,000		54,630		50,379		40,487
Non Cash Adjustment Derivative Fair Value			1,600	(200)	32,900	1,700	(600)	(200)	(4,300)	400		35,934		(4,797)		(28,273)
Non-cash Foreign Currency Translation Charges			300	200	1,900	800
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability												140		5,320		8,688
Valuation allowance			400,171				366,825					400,171		366,825
Product Rationalization Costs							(8,300)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings			700	300	400	400
Tax Benefit Related to the Realizability of Net Operating Losses							(16,000)	(8,900)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax												0		0		(21,342)
Discontinued Operation, Tax Effect of Discontinued Operation			3,800	2,200	(6,200)
Continuing Operations [Member]
Operating expenses:
Inventory write-down												20,900		19,200		21,500
PROFEMUR Titanium Modular Neck Product [Member]
Operating expenses:
Increase Decrease in Estimated Recovery from Third Party											$ 19,400
Cartiva, Inc. [Member]
Quarterly Financial Information [Line Items]
InventoryStepUpAmortizationExpenseContinuingOperations			400									400
Net sales												9,500
Operating expenses:
Amortization of intangible assets												1,900
Operating income												2,400
Valuation allowance			3,600									3,600
Tornier N.V. [Member]
Operating expenses:
Business Combination, Acquisition Related Costs							2,900	3,300	3,200	3,000
Contingent Value Rights [Member] | Continuing Operations [Member]
Operating expenses:
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			3,200	$ 3,400	(2,500)	$ (3,900)	(1,400)	4,500	(3,900)	$ 6,200
2017 Notes Conversion Derivative [Member]
Operating expenses:
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees														3,000		25,100
Contingent Consideration [Member]
Operating expenses:
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings							(200)	$ 100	200			(1,789)
incentive and indirect [Member]
Quarterly Financial Information [Line Items]
Income Tax Expense (Benefit)							(800)							(9,000)
incentive and indirect [Member] | Operating Expense [Member]
Quarterly Financial Information [Line Items]
Income Tax Expense (Benefit)							$ (9,000)
Insurance Carrier [Member]
Operating expenses:
Proceeds from Legal Settlements		$ 30,750
Valuation Allowance of Deferred Tax Assets [Member]
Operating expenses:
Valuation allowance			$ (2,700)									(2,700)
2020 convertibledebt [Member]
Operating expenses:
Amortization of Debt Discount (Premium)												$ 19,100		$ 27,300		$ 25,900
Write off of pro-rata unamortized deferred financing fees and for bank and legal fees	$ 39,900				$ 39,900				$ 9,300
[1]	Cost of sales includes amortization of inventory step-up adjustment of $37.7 million for the fiscal year ended December 25, 2016.
[2]	These line items include the following amounts of non-cash, share-based compensation expense for the periods indicated: Fiscal year ended December 30, 2018 December 31, 2017 December 25, 2016Cost of sales$585 $565 $414Selling, general and administrative23,608 17,705 13,216Research and development1,927 1,123 786
[3]	The Corporate category primarily reflects general and administrative expenses not specifically associated with the U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics segments. These non-allocated corporate expenses relate to global administrative expenses that support all segments, including salaries and benefits of certain executive officers and expenses such as: information technology administration and support; corporate headquarters; legal, compliance, and corporate finance functions; insurance; and all share-based compensation.

Segment Data (Details)

Segment Data (Details) $ in Thousands		3 Months Ended									12 Months Ended
		Dec. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Jul. 01, 2018USD ($)	Apr. 01, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 24, 2017USD ($)	Jun. 25, 2017USD ($)	Mar. 26, 2017USD ($)	Mar. 27, 2016	Dec. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 25, 2016USD ($)
Segment Reporting Information [Line Items]
Capital Expenditures, Continuing Operations											$ 71,467	$ 63,474	$ 50,099
Payments to Acquire Property, Plant, and Equipment											71,467	63,474	50,099
Net sales		$ 238,147	$ 194,106	$ 205,400	$ 198,537	$ 217,602	$ 170,503	$ 179,693	$ 177,191		$ 836,190	744,989	690,362
Concentration risk percentage											10.00%
Depreciation											$ 59,500	56,800	55,800
Operating Income (Loss)		3,886	(9,134)	(1,658)	(890)	17,209	(18,509)	(8,793)	(9,598)		(7,796)	(19,691)	(122,958)
Interest Income (Expense), Nonoperating, Net											80,247	74,644	58,530
InventoryStepUpAmortizationExpense											352	0	41,503
Business Combination, Acquisition Related Costs, Transaction											12,013	12,400	36,374
Income Tax Expense (Benefit)											(536)	(34,968)	(13,406)
Management Changes													1,348
Payments of Debt Restructuring Costs													234
Other Nonoperating Income (Expense)											81,797	5,570	(3,148)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest											(169,840)	(99,905)	(178,340)
Assets		2,694,401				2,128,724					2,694,401	2,128,724
Goodwill		1,268,954				933,662					1,268,954	933,662	851,042
Amortization of Intangible Assets		7,699	$ 5,881	$ 6,009	$ 7,141	6,822	$ 7,178	$ 6,999	$ 7,397		26,730	28,396	28,841	[1]
EMEA [Member]
Segment Reporting Information [Line Items]
Net sales											153,375	137,772	132,178
UNITED STATES
Segment Reporting Information [Line Items]
Net sales											623,538	554,511	507,547
Other
Segment Reporting Information [Line Items]
Net sales											59,277	52,706	50,637
Extremities & Biologics [Member] | EMEA [Member]
Segment Reporting Information [Line Items]
Net sales											8,312	8,445	8,149
Extremities & Biologics [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Capital Expenditures, Continuing Operations											17,566	19,555	13,517
Net sales											212,652	190,478	182,815
Depreciation											13,004	12,366	11,427
Assets		272,127				301,985					272,127	301,985
Goodwill		71,134				84,487					71,134	84,487	73,848
AmortizationExpenseWithoutDistributorConversion											0	0	0
Segment Operating Loss											1,492	3,631	5,872
Extremities & Biologics [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales											83,077	78,361	74,603
Extremities & Biologics [Member] | Other
Segment Reporting Information [Line Items]
Net sales											17,445	13,831	10,734
Lower Extremities & Biologics [Member] | EMEA [Member]
Segment Reporting Information [Line Items]
Net sales											46,342	42,333	43,805
Lower Extremities & Biologics [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales											250,735	228,044	222,936
Lower Extremities & Biologics [Member] | Other
Segment Reporting Information [Line Items]
Net sales											14,407	16,140	18,896
Upper Extremities [Member] | EMEA [Member]
Segment Reporting Information [Line Items]
Net sales											87,647	73,243	66,819
Upper Extremities [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales											281,314	239,965	201,579
Upper Extremities [Member] | Other
Segment Reporting Information [Line Items]
Net sales											26,813	21,456	19,683
Sports Med And Other [Member] | EMEA [Member]
Segment Reporting Information [Line Items]
Net sales											11,074	13,751	13,405
Sports Med And Other [Member] | UNITED STATES
Segment Reporting Information [Line Items]
Net sales											8,412	8,141	8,429
Sports Med And Other [Member] | Other
Segment Reporting Information [Line Items]
Net sales											612	1,279	1,324
UNITED STATES | Lower Extremities & Biologics [Member]
Segment Reporting Information [Line Items]
Capital Expenditures, Continuing Operations											21,153	19,355	13,145
Net sales											337,433	309,713	300,847
Depreciation											11,131	12,532	13,000
Assets		940,075				490,528					940,075	490,528
Goodwill		569,970				218,525					569,970	218,525	218,525
AmortizationExpenseWithoutDistributorConversion											0	0	0
Segment Operating Loss											96,153	79,889	85,645
UNITED STATES | Upper Extremities [Member]
Segment Reporting Information [Line Items]
Capital Expenditures, Continuing Operations											26,346	22,897	10,101
Net sales											286,105	244,798	206,700
Depreciation											12,439	10,211	11,190
Assets		923,036				929,930					923,036	929,930
Goodwill		627,850				630,650					627,850	630,650	558,669
AmortizationExpenseWithoutDistributorConversion											0	0	0
Segment Operating Loss											97,644	78,866	65,231
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Capital Expenditures, Continuing Operations	[1]										6,402	1,667	13,336
Net sales	[1]										0	0	0
Depreciation	[1]										22,923	21,723	20,213
Assets		$ 559,163				406,281					559,163	406,281
AmortizationExpenseWithoutDistributorConversion	[1]										26,730
Amortization of Intangible Assets	[1]											28,396
Segment Operating Loss	[1]										$ (190,720)	(178,642)	(202,261)
segment [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments										4	3
Depreciation											$ 59,497	56,832	55,830
AmortizationExpenseWithoutDistributorConversion											26,730	28,396	28,841
Segment Operating Loss											$ 4,569	(16,256)	$ (45,513)
incentive and indirect [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)						$ (800)						$ (9,000)
[1]	The Corporate category primarily reflects general and administrative expenses not specifically associated with the U.S. Lower Extremities & Biologics, U.S. Upper Extremities, and International Extremities & Biologics segments. These non-allocated corporate expenses relate to global administrative expenses that support all segments, including salaries and benefits of certain executive officers and expenses such as: information technology administration and support; corporate headquarters; legal, compliance, and corporate finance functions; insurance; and all share-based compensation.

Schedule II - Valuation and Q_3

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 4,328	$ 4,469	$ 1,189
Charged to Cost and Expenses	189	1,243	3,475
Deductions and Other	(1,472)	(1,384)	(195)
Balance at End of Period	$ 3,045	$ 4,328	$ 4,469

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Feb. 24, 2019	Jul. 30, 2018	Jun. 28, 2018	Dec. 30, 2018	May 31, 2018	Dec. 31, 2017	Dec. 25, 2016	Nov. 24, 2015	Oct. 01, 2015	Sep. 30, 2015	Feb. 13, 2015
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 150,000
2023 Convertible Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount			$ 675,000	$ 675,000
Debt Instrument, Convertible, Conversion Price			$ 33.37
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				20.2
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 40.86
2020 convertibledebt [Member]
Subsequent Event [Line Items]
Debt Conversion, Converted Instrument, Amount			$ 400,900
Debt Instrument, Convertible, Conversion Price								$ 29.94		$ 30.87
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				6.2		19.6	19.6				21.1
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 38.8010		$ 40
Proceeds from Warrant Exercises		$ 10,600
Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 40,000
Debt Instrument, Tranche 2 [Member] | Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 20,000
Maximum [Member] | Line of Credit [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 100,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 175,000
Subsequent Event [Member] | 2023 Note Hedges [Member]
Subsequent Event [Line Items]
Payments For Warrants	30,100
Proceeds From Derivatives Settled	21,200
Subsequent Event [Member] | 2023 Convertible Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	814,600
Proceeds from Warrant Exercises	8,900
Subsequent Event [Member] | 2020 convertibledebt [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	56,500
Debt Conversion, Converted Instrument, Amount	$ 130,100
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	1.9
Subsequent Event [Member] | Additional 2023 Convertible Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 139,600
Debt Instrument, Convertible, Conversion Price	$ 33.37
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	4.2
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 40.86
Subsequent Event [Member] | Debt Instrument, Tranche 2 [Member] | Line of Credit [Member] | Term Loan [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 35,000
Subsequent Event [Member] | Maximum [Member] | Line of Credit [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 75,000