Nuvasive (NUVA) 10-Q 30 Jul 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 21, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'NUVASIVE INC	'
Entity Central Index Key	'0001142596	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	46,976,047

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$106,461	$102,825
Short-term marketable securities	140,849	143,449
Accounts receivable, net of allowances of $4,495 and $3,481, respectively	112,572	104,774
Inventory	157,361	136,937
Deferred tax assets, current	37,105	37,076
Income Taxes Receivable, Current	21,013	0
Prepaid expenses and other current assets	11,774	10,947
Total current assets	587,135	536,008
Property and equipment, net	134,863	128,064
Long-term marketable securities	102,920	79,829
Intangible assets, net	75,312	93,986
Goodwill	154,637	154,944
Deferred tax assets, non-current	46,886	42,863
Restricted cash and investments	123,140	119,195
Other assets	29,231	24,679
Total assets	1,254,124	1,179,568
Current liabilities:	'	'
Accounts payable and accrued liabilities	102,224	86,057
Accrued payroll and related expenses	26,966	31,095
Current Litigation Liability	30,000	0
Total current liabilities	159,190	117,152
Senior Convertible Notes	353,269	346,060
Deferred tax liabilities, non-current	2,980	2,934
Litigation liability	93,700	93,700
Other long-term liabilities	16,674	14,844
Commitments and contingencies	'	'
Stockholders' equity:	'	'
Preferred stock, $0.001 par value; 5,000,000 shares authorized, none outstanding	0	0
Common stock, $0.001 par value; 120,000,000 shares authorized at June 30, 2014 and December 31, 2013, respectively, 46,941,192 and 44,943,233 issued and outstanding at June 30, 2014 and December 31, 2013, respectively	47	45
Additional paid-in capital	813,541	769,203
Accumulated other comprehensive loss	-1,299	-3,238
Accumulated deficit	-192,582	-170,218
Treasury Stock, Value	-44	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	628,311	604,878
Noncontrolling Interest in Variable Interest Entity	8,648	9,086
Total stockholders' equity	619,663	595,792
Total liabilities and stockholders' equity	$1,254,124	$1,179,568

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Reserves For Accounts Receivable And Sales Returns	$4,495	$3,481
Preferred stock, par value (in usd per share)	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in usd per share)	$0.00	$0.00
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	46,941,192	44,943,233
Common stock, shares outstanding	46,941,192	44,943,233
Treasury Stock, Shares	1,285	0

Unaudited_Condensed_Consolidat

Unaudited Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue	$190,677	$165,698	$368,172	$325,202
Cost of goods sold (excluding amortization of purchased technology)	44,836	48,744	88,130	87,840
Gross profit	145,841	116,954	280,042	237,362
Operating expenses:	'	'	'	'
Sales, marketing and administrative	116,970	104,272	235,074	204,158
Research and development	10,067	7,712	19,522	17,407
Amortization of intangible assets	3,473	4,913	7,470	9,288
Goodwill and Intangible Asset Impairment	10,708	0	10,708	0
Litigation Award	0	0	30,000	0
Total operating expenses	141,218	116,897	302,774	230,853
Interest and other expense, net:	'	'	'	'
Interest income	233	231	450	403
Interest expense	-6,979	-6,652	-13,844	-13,685
Other (expense) income, net	-205	-440	171	-199
Total interest and other expense, net	-6,951	-6,861	-13,223	-13,481
Loss before income taxes	-2,328	-6,804	-35,955	-6,972
Income tax expense (benefit)	1,942	-76	-13,153	-840
Consolidated net loss	-4,270	-6,728	-22,802	-6,132
Net loss attributable to noncontrolling interests	-182	-259	-438	-514
Net loss attributable to NuVasive, Inc.	($4,088)	($6,469)	($22,364)	($5,618)
Net loss per share attributable to NuVasive, Inc.:	'	'	'	'
Earnings Per Share, Basic	($0.09)	($0.15)	($0.48)	($0.13)
Earnings Per Share, Diluted	($0.09)	($0.15)	($0.48)	($0.13)
Weighted average shares outstanding:	'	'	'	'
Basic (in shares)	46,832	44,412	46,320	44,220
Diluted (in shares)	46,832	44,412	46,320	44,220

Unaudited_Condensed_Consolidat1

Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Consolidated net loss	($4,270)	($6,728)	($22,802)	($6,132)
Other comprehensive loss:	'	'	'	'
Unrealized loss on marketable securities, net of tax	-62	-229	-74	-270
Translation adjustments, net of tax	942	-2,141	2,013	-3,929
Other comprehensive income (loss)	880	-2,370	1,939	-4,199
Total consolidated comprehensive loss	-3,390	-9,098	-20,863	-10,331
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	-182	'	-438	0
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	'	259	0	514
Comprehensive loss attributable to NuVasive, Inc.	($3,208)	($8,839)	($20,425)	($9,817)

Unaudited_Condensed_Consolidat2

Unaudited Condensed Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Operating activities:	'	'
Consolidated net loss	($22,802)	($6,132)
Adjustments to reconcile net loss to net cash provided by operating activities:	'	'
Depreciation and amortization	31,043	30,341
Amortization of Financing Costs and Discounts	8,081	7,569
Stock-based compensation	16,549	15,548
Valuation Allowances and Reserves, Period Increase (Decrease)	2,383	1,783
Other non-cash adjustments	4,114	4,175
Changes in operating assets and liabilities, net of effects from acquisitions:	'	'
Accounts receivable	-8,603	-8,443
Inventory	-20,930	-13,680
Prepaid expenses and other current assets	-2,839	-1,722
Accounts payable and accrued liabilities	5,080	8,830
Increase Decrease In Litigation Liability	-30,000	0
Accrued payroll and related expenses	-4,473	-5,885
Net cash provided by operating activities	48,311	32,384
Goodwill and Intangible Asset Impairment	10,708	0
Investing activities:	'	'
Cash paid for business and asset acquisitions	-59	-7,719
Purchases of property and equipment	-32,560	-26,209
Purchases of marketable securities	-129,080	-136,988
Sales of marketable securities	-103,650	-145,014
Net cash used in investing activities	-58,049	-25,902
Financing activities:	'	'
Principal payment of 2013 Senior Convertible Notes	0	-74,311
Excess Tax Benefit from Share-based Compensation, Financing Activities	0	1,261
Proceeds from the issuance of common stock	14,193	3,123
Payments for Repurchase of Common Stock	-44	0
Other assets	-1,142	26
Net cash provided by (used in) financing activities	13,007	-69,901
Effect of exchange rate changes on cash	367	-1,000
Increase (decrease) in cash and cash equivalents	3,636	-64,419
Cash and cash equivalents at beginning of period	102,825	123,299
Cash and cash equivalents at end of period	$106,461	$58,880

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business and Basis of Presentation	'
	Description of Business and Basis of Presentation
	Description of Business.    NuVasive, Inc. (the "Company" or "NuVasive") was incorporated in Delaware on July 21, 1997, and began commercializing its products in 2001. The Company is focused on developing minimally-disruptive surgical products and procedurally-integrated solutions for the spine. NuVasive's principal product offering includes a minimally-disruptive surgical platform called "Maximum Access Surgery", or "MAS®", as well as an offering of biologics, cervical and motion preservation products. The MAS platform combines three categories of solutions that collectively minimize soft tissue disruption during spine fusion surgery, provide maximum visualization and are designed to enable reproducible outcomes for the surgeon. The platform includes the Company's proprietary nerve monitoring systems (which include software-driven nerve detection and avoidance systems (called "NVM5®" and "NVJJB") and accompanying intra-operative monitoring ("IOM") support); MaXcess®, an integrated split-blade retractor system; and a wide variety of specialized implants. The individual components of NuVasive's MAS platform, and many of the Company's products, can also be used in open or traditional spine surgery. The Company continues to focus significant research and development efforts to expand its MAS product platform and advance the applications of its unique technology into procedurally integrated surgical solutions. The Company dedicates significant resources toward training spine surgeons on its unique technology and products.
	The Company's primary business model is to loan its MAS systems to surgeons and hospitals who purchase implants, biologics, and disposables for use in individual procedures. In addition, for larger customers, the Company places its proprietary nerve monitoring systems, MaXcess and surgical instrument sets with hospitals for an extended period at no up-front cost to them. The Company also offers a range of bone allograft in patented saline packaging, disposables and spine implants, which include its branded CoRoent® products and fixation devices such as rods, plates and screws. Implants, biologics and disposables are shipped from the Company’s inventories. The Company sells an immaterial quantity of MAS instrument sets, MaXcess and nerve monitoring systems to hospitals.
	Basis of Presentation and Principles of Consolidation.    The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its majority-owned or controlled subsidiaries, collectively referred to as either NuVasive or the Company. The Company translates the financial statements of its foreign subsidiaries using end-of-period exchange rates for assets and liabilities and average exchange rates during each reporting period for results of operations. When there is a portion of equity in an acquired subsidiary not attributable, directly or indirectly, to the respective parent entity, the Company records the fair value of the noncontrolling interests at the acquisition date and classifies the amounts attributable to noncontrolling interests separately in equity in the Company’s condensed consolidated financial statements. Any subsequent changes in a parent’s ownership interest while the parent retains its controlling financial interest in its subsidiary are accounted for as equity transactions. All significant intercompany balances and transactions have been eliminated in consolidation.
	The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the "SEC"). Pursuant to these rules and regulations, the Company has condensed or omitted certain information and footnote disclosures it normally includes in its annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Operating results for the three and six months ended June 30, 2014 are not necessarily indicative of the results that may be expected for any other interim period or for the full year. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2013 included in NuVasive’s Annual Report on Form 10-K filed with the SEC. In the opinion of Management, the condensed consolidated financial statements include all adjustments that are of a normal and recurring nature that are necessary for the fair presentation of the Company's financial position and of the results of operations and cash flows for the periods presented.
	Change in Accounting Estimate.    The preparation of financial statements in conformity with GAAP requires Management to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	During the three and six months ended June 30, 2014, the Company committed to a plan to consolidate its offices located in San Diego, California into one corporate headquarters for efficiency purposes. This project is expected to start during the third quarter of 2014 and be completed by March 31, 2015. As a result, certain long-lived assets, primarily leasehold improvements, will be abandoned and replaced during the respective construction period. In accordance with the authoritative guidance, the Company has shortened the depreciable lives of impacted assets, which resulted in approximately $0.5 million of accelerated depreciation, which is included in sales, marketing and administrative expenses, during the three and six months ended June 30, 2014. Based on the current construction schedules, the Company expects to accelerate approximately $4.1 million of depreciation during the full year ended December 31, 2014 that would have otherwise been recorded in future periods.
	At the beginning of 2014, the Company completed a review of the estimated useful life of the international surgical instrument sets used in support of its business outside of the United States. Based on historical useful life information, as well as forecasted product life cycles and demand expectations, the useful life of certain international surgical instrument sets was extended from three to four years, which is consistent with the depreciable lives of such sets domestically. In accordance with authoritative guidance, this was accounted for as a change in accounting estimate and was made on a prospective basis effective January 1, 2014. For the three and six months ended June 30, 2014, depreciation expense, which is included in sales, marketing and administrative expenses, was approximately $0.7 million and $1.4 million less, respectively, than it would have been had the useful life of these assets not been extended. The Company expects to have a $2.8 million favorable impact to its consolidated statement of operations, for the full year ended December 31, 2014 due to this change in estimate. The total net impact to the Company's consolidated statement of operations for all four years affected by the change will be zero.
	Comprehensive Income (Loss).    Comprehensive income (loss) is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income (loss) includes unrealized gains or losses on the Company’s marketable securities and foreign currency translation adjustments. The cumulative translation adjustments included in accumulated other comprehensive income (loss) were a net cumulative loss of $1.2 million and $3.3 million at June 30, 2014 and December 31, 2013, respectively.
	Long-Lived Assets.    Long-lived assets primarily include surgical instruments, which are loaned to surgeons and hospitals who purchase implants, biologics and disposables for use in individual procedures, as well as certain intangible assets. The Company periodically re-evaluates the original assumptions and rationale utilized in the establishment of the carrying value and estimated lives of its long-lived assets. The criteria used for these evaluations include Management’s estimate of the asset’s continuing ability to generate income from operations and positive cash flow in future periods as well as the strategic significance of any intangible asset to the Company’s business objectives. If assets are considered to be impaired, the impairment recognized is the amount by which the carrying value of the assets exceeds the fair value of the assets, which is determined by applicable market prices when available or other methods by utilizing unobservable inputs including discounted cash flow models. See Note 4, Financial Instruments and Fair Value Measurements for further discussion.
	Inventories.    The Company’s inventory consists primarily of purchased finished goods which includes specialized implants and disposables, and is stated at the lower of cost or market determined by a weighted average cost method. The Company reviews the components of its inventory on a periodic basis for excess, obsolete or impaired inventory, and records a reserve for such identified items. The inventory reserve was $23.3 million and $21.9 million at June 30, 2014 and December 31, 2013, respectively.
	Pending Adoption of Recent Accounting Pronouncements.    In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update No. 2014-09, Revenue from Contracts with Customers, (“ASU 2014-09”) an updated standard on revenue recognition. ASU 2014-09 provides enhancements to the quality and consistency of how revenue is reported by companies while also improving comparability in the financial statements of companies reporting using International Financial Reporting Standards or GAAP. The main purpose of the new standard is for companies to recognize revenue to depict the transfer of goods or services to customers in amounts that reflect the consideration to which a company expects to be entitled in exchange for those goods or services. The new standard also will result in enhanced disclosures about revenue, provide guidance for transactions that were not previously addressed comprehensively and improve guidance for multiple-element arrangements. ASU 2014-09 will be effective for the Company in the first quarter of fiscal year 2017 and may be applied on a full retrospective or modified retrospective approach. The Company is still evaluating the impact of implementation of this standard on its financial statements.

Net_Income_Per_Share

Net Income Per Share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Net Income (Loss) Per Share	'
	Net Income (Loss) Per Share
	The Company computes basic net income (loss) per share using the weighted-average number of common shares outstanding during the period. Diluted net income (loss) per share assumes the conversion, exercise or issuance of all potential common stock equivalents, unless the effect of inclusion would be anti-dilutive. For purposes of this calculation, common stock equivalents include the Company’s stock options, employee stock purchase plan shares, restricted stock units, including those with performance conditions, warrants, and shares to be issued upon the conversion of the Senior Convertible Notes (see Note 6, Senior Convertible Notes).
	The following table sets forth the computation of basic and diluted earnings or (loss) per share attributable to the Company (in thousands, except per share data):
		Three Months Ended							Six Months Ended
		June 30,							June 30,
		2014				2013			2014			2013
	Numerator:
	Net loss attributable to the Company	$	(4,088	)		$	(6,469	)	$	(22,364	)	$	(5,618	)
	Denominator for basic and diluted net income per share:
	Weighted average common shares outstanding for basic	46,832				44,412			46,320			44,220
	Weighted average common shares outstanding for diluted	46,832				44,412			46,320			44,220
	Basic net loss per share attributable to the Company	$	(0.09	)		$	(0.15	)	$	(0.48	)	$	(0.13	)
	Diluted net loss per share attributable to the Company	$	(0.09	)		$	(0.15	)	$	(0.48	)	$	(0.13	)
	The following weighted outstanding common stock equivalents were not included in the calculation of net income (loss) per diluted share because their effects were anti-dilutive (in thousands):
		Three Months Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014		2013
	Stock options, ESPP shares and restricted stock units	8,949			7,953			8,409		7,518
	Warrants	9,553			14,641			9,553		14,667
	Senior Convertible Notes	9,553			9,553			9,553		10,232
	Total	28,055			32,147			27,515		32,417

Business_Combinations

Business Combinations	6 Months Ended
	Jun. 30, 2014
Business Combination, Description [Abstract]	'
Business Combinations	'
	Business Combinations
	During its history, the Company has completed acquisitions that were not considered individually or collectively material to the overall consolidated financial statements and the results of the Company’s operations. These acquisitions have been included in the consolidated financial statements from the respective dates of the acquisitions. The Company recognizes the assets acquired, liabilities assumed, and any noncontrolling interest at fair value at the date of acquisition. Certain acquisitions contain contingent consideration arrangements that require the Company to assess the acquisition date fair value of the contingent consideration liabilities, which is recorded as part of the purchase consideration of the acquisition. The Company continuously assesses and adjusts the fair value of the contingent consideration liabilities, if necessary, until the settlement or expiration of the contingency occurs.
	Contingent Consideration Liabilities
	As a result of contingent consideration arrangements associated with certain asset and/or business acquisitions, the Company may have (or at times following such transactions, have had) future payment obligations based on certain technological or operational milestones. In accordance with the authoritative guidance, the Company records these obligations at fair value at the time of acquisition with subsequent fair value adjustments to the contingent consideration reflected in the line items of the condensed consolidated statement of operations commensurate with the nature of the contingent consideration. At June 30, 2014, the estimated fair value of existing contingent consideration agreements, individually or collectively, are not considered material to the Company’s consolidated financial statements. Refer to Note 4, Financial Instruments and Fair Value Measurements for further discussion on fair market valuation and subsequent changes.
	Progentix Orthobiology B.V.
	In 2009, the Company completed the purchase of 40% of the capital stock of Progentix Orthobiology B.V. ("Progentix"), a company organized under the laws of the Netherlands, from existing shareholders pursuant to a Preferred Stock Purchase Agreement for $10 million in cash (the "Initial Investment"). NuVasive and Progentix also entered into a Distribution Agreement, as amended, whereby Progentix appointed NuVasive as its exclusive distributor for certain Progentix products. The Distribution Agreement is in effect for a term of ten years unless terminated earlier in accordance with its terms.
	Progentix is determined to be a variable interest entity ("VIE") in accordance with authoritative guidance, and NuVasive has a controlling financial interest in the VIE as NuVasive has both (1) the power to direct the economically significant activities of Progentix, and (2) the obligation to absorb losses of, or the right to receive benefits from Progentix. Accordingly, the financial position and results of operations of Progentix have been included in the Company’s consolidated financial statements since the date of the Initial Investment. The liabilities recognized as a result of consolidating Progentix do not represent additional claims on the Company’s general assets. The creditors of Progentix have claims only on the assets of Progentix, which are not material, and the assets of Progentix are not available to NuVasive.
	The equity interests in Progentix not owned by the Company, which includes shares of both common and preferred stock, are reported as noncontrolling interests on the consolidated balance sheet of the Company. The preferred stock represents 18% of the noncontrolling equity interests and provides for a cumulative 8% dividend, if and when declared by Progentix’s Board of Directors. As the rights of the preferred stock are substantially the same as those of the common stock, the preferred stock is classified as a noncontrolling interest and shares in the allocation of the losses incurred by Progentix. Gains or losses incurred by Progentix are absorbed by the Company and the noncontrolling interest holders based on the respective ownership percentages.
	Total assets and liabilities of Progentix included in the accompanying condensed consolidated balance sheet are as follows (in thousands):
		June 30, 2014		December 31, 2013
	Total current assets	$	549	$	580
	Identifiable intangible assets, net	14,169		14,403
	Goodwill	12,654		12,654
	Other long-term assets	4		7
	Accounts payable and accrued expenses	522		403
	Deferred tax liabilities, net	2,770		2,770
	Noncontrolling interests	8,648		9,086
	The following is a reconciliation of equity (net assets) attributable to the noncontrolling interests (in thousands):
		Six Months Ended June 30,
		2014		2013
	Noncontrolling interests at beginning of period	$	9,086	$	10,003
	Less: Net loss attributable to the noncontrolling interests prior to reclassification from mezzanine to equity	—		514
	Less: Net loss attributable to the noncontrolling interests subsequent to reclassification from mezzanine to equity	438		—
	Noncontrolling interests at end of period	$	8,648	$	9,489
	Impulse Monitoring Inc. and Physician Practices
	The Company maintains contractual relationships with several physician practices ("PCs") which were inherited through the 2011 acquisition of Impulse Monitoring Inc. Under the respective contracts' terms, PCs provide the physician oversight services associated with IOM services. The Company provides management services to the PCs including all non-medical services, management reporting, billing and collections of all charges for medical services provided as well as administrative support. The PCs pay the Company a monthly management fee for these services. In accordance with authoritative guidance, the Company has determined that the PCs are variable interest entities and NuVasive has controlling financial interests in the PCs as NuVasive has both (1) the power to direct the economically significant activities of the PCs and (2) the obligation to absorb losses of, or the right to receive benefits from, the PCs. Therefore, the accompanying condensed consolidated financial statements include the accounts of the PCs from the date of acquisition. The creditors of the PCs have claims only on the assets of the PCs, which are not material, and the assets of the PCs are not available to the Company.

Financial_Instruments_and_Fair

Financial Instruments and Fair Value Measurements	6 Months Ended
	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Financial Instruments and Fair Value Measurements	'
	Financial Instruments and Fair Value Measurements
	The Company invests its excess cash in certificates of deposit, corporate notes, commercial paper, U.S. government treasury securities and securities of government-sponsored entities. The Company classifies all such securities as available-for-sale, as the sale of such securities may be required prior to maturity to implement management strategies. These securities are carried at fair value with the unrealized gains and losses reported as a component of other comprehensive income in equity until realized. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense on the condensed consolidated statements of operations and a new cost basis for the security is established. The Company reviews its investments if there is an indicator of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. As of June 30, 2014, the Company had no investments that were in a significant unrealized loss position and no impairment charges were recorded during the periods presented.
	According to the Company's investment policy, the Company maintains a diversified investment portfolio in terms of types, maturities, and credit exposure, and invests with institutions that have high credit quality. The Company does not currently hold derivative financial investments or speculative investments. Interest and dividends on securities classified as available-for-sale are also included in interest income on the condensed consolidated statements of operations. Realized gains and losses and interest income and expense related to marketable securities were immaterial during all periods presented.
	The composition of marketable securities is as follows (in thousands, except years):
		Contractual		Amortized Cost				Gross				Gross				Fair Value
		Maturity						Unrealized				Unrealized
		(in Years)						Gains				Losses
	June 30, 2014:
	Classified as current assets
	Certificates of deposit	Less than 1		$	869			$	—			$	—			$	869
	Corporate notes	Less than 1		79,198				20				(35		)		79,183
	Commercial paper	Less than 1		10,000				—				—				10,000
	U.S. government treasury securities	Less than 1		1,500				2				—				1,502
	Securities of government-sponsored entities	Less than 1		49,266				31				(2		)		49,295
	Total short-term marketable securities			140,833				53				(37		)		140,849
	Classified as non-current assets
	Certificates of deposit	1 to 2		—				—				—				—
	Corporate notes	1 to 2		57,940				11				(59		)		57,892
	Securities of government-sponsored entities	1 to 2		45,056				8				(36		)		45,028
	Total long-term marketable securities			102,996				19				(95		)		102,920
	Classified as restricted investments
	U.S. government treasury securities	Less than 2		47,823				43				(2		)		47,864
	Securities of government-sponsored entities	Less than 2		30,500				4				(21		)		30,483
	Total restricted investments			78,323				47				(23		)		78,347
	Total marketable securities at June 30, 2014			$	322,152			$	119			$	(155	)		$	322,116
	December 31, 2013:
	Classified as current assets
	Certificates of deposit	Less than 1		$	833			$	—			$	—			$	833
	Corporate notes	Less than 1		71,611				23				(6		)		71,628
	Commercial paper	Less than 1		19,973				—				—				19,973
	U.S. government treasury securities	Less than 1		7,603				2				—				7,605
	Securities of government-sponsored entities	Less than 1		43,405				14				(9		)		43,410
	Total short-term marketable securities			143,425				39				(15		)		143,449
	Classified as non-current assets
	Certificates of deposit	1 to 2		283				—				—				283
	Corporate notes	1 to 2		32,309				23				(14		)		32,318
	U.S. government treasury securities	1 to 2		1,500				1				—				1,501
	Securities of government-sponsored entities	1 to 2		45,722				19				(14		)		45,727
	Total long-term marketable securities			79,814				43				(28		)		79,829
	Classified as restricted investments
	U.S. government treasury securities	Less than 2		43,274				16				(6		)		43,284
	Securities of government-sponsored entities	Less than 2		29,125				4				(16		)		29,113
	Total restricted investments			72,399				20				(22		)		72,397
	Total marketable securities at December 31, 2013			$	295,638			$	102			$	(65	)		$	295,675
	Fair value measurements
	The Company measures certain assets and liabilities in accordance with authoritative guidance which requires fair value measurements be classified and disclosed in one of the following three categories:
	Level 1: Quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities.
	Level 2: Observable prices that are based on inputs not quoted on active markets, but corroborated by market data.
	Level 3: Unobservable inputs are used when little or no market data is available.
	Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels for certain assets or liabilities within the fair value hierarchy. The Company did not have any transfers of assets and liabilities between Level 1 and Level 2 of the fair value measurement hierarchy during the six months ended June 30, 2014 or June 30, 2013.
	The carrying amounts of other financial instruments such as cash equivalents, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses, and other current liabilities as of June 30, 2014 and December 31, 2013 approximate their related fair values due to the short-term maturities of these instruments. The carrying values of the Company’s capital lease obligations approximate their related fair values as of June 30, 2014 and December 31, 2013.
	The fair value, based on a quoted market price (Level 1), of the Company's outstanding Senior Convertible Notes due 2017 at June 30, 2014 and December 31, 2013 was approximately $458.9 million and $439.3 million, respectively. The carrying value of the Company’s Senior Convertible Notes is discussed in Note 6, Senior Convertible Notes.
	The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):
		Total				Quoted Price in				Significant Other				Significant
						Active Market				Observable Inputs				Unobservable
						(Level 1)				(Level 2)				Inputs (Level 3)
	June 30, 2014:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	55,092			$	55,092			$	—			$	—
	Certificates of deposit	869				869				—				—
	Corporate notes	137,075				—				137,075				—
	Commercial paper	10,000				—				10,000				—
	U.S. government treasury securities	49,366				49,366				—				—
Securities of government-sponsored entities	124,806				—				124,806				—
Total cash equivalents, marketable securities and restricted investments	$	377,208			$	105,327			$	271,881			$	—
Contingent Consideration:
Acquisition-related liabilities, current	$	(648	)		$	—			$	—			$	(648	)
Total contingent consideration	$	(648	)		$	—			$	—			$	(648	)
December 31, 2013:
Cash Equivalents, Marketable Securities and Restricted Investments:
Money market funds	$	72,514			$	72,514			$	—			$	—
Certificates of deposit	1,116				1,116				—				—
Corporate notes	103,946				—				103,946				—
Commercial paper	19,973				—				19,973				—
U.S. government treasury securities	52,390				52,390				—				—
Securities of government-sponsored entities	118,250				—				118,250				—
Total cash equivalents, marketable securities and restricted investments	$	368,189			$	126,020			$	242,169			$	—
Contingent Consideration:
Acquisition-related liabilities, current	$	(616	)		$	—			$	—			$	(616	)
Acquisition-related liabilities, non-current	$	(596	)		$	—			$	—			$	(596	)
Total contingent consideration	$	(1,212	)		$	—			$	—			$	(1,212	)
Contingent Consideration Liability
As a result of contingent consideration arrangements associated with certain immaterial asset and/or business acquisitions, the Company may have (or at times following such transactions, have had) future payment obligations which are based on certain technological or operational milestones. The Company records these obligations at fair value at the time of acquisition with subsequent fair value adjustments to the contingent consideration reflected in the line items of the condensed consolidated statement of operations commensurate with the nature of the contingent consideration. The fair value of the contingent consideration was determined using a discounted cash flow model, the significant inputs of which are not observable in the market. The key assumptions in applying this approach are the revenue projections, the interest rate and the probabilities assigned to the milestones being achieved. Reasonable changes in the unobservable inputs would not be expected to have a significant impact on the Company’s condensed consolidated financial statements.
In connection with an immaterial acquisition completed in 2012, the Company agreed to pay the seller an amount not to exceed €2.0 million in aggregate in the event two specified revenue-based milestones are achieved. The first milestone was achieved and paid during the six months ended June 30, 2014. The second milestone will be measured in February 2015. The Company has a remaining contingent consideration accrual at June 30, 2014 of $0.6 million with respect to the second milestone. Changes in fair value are recorded in the statements of operations as sales, marketing and administrative expenses.
The following table sets forth the changes in the estimated fair value of the Company’s liabilities measured on a recurring basis using significant unobservable inputs (Level 3) (in thousands):
	Six Months Ended June 30,
	2014				2013
Fair value measurement at beginning of period	$	1,212			$	1,074
Change in fair value measurement included in operating expenses	44				15
Contingent consideration paid or settled	(608		)		—
Fair value measurement at end of period	$	648			$	1,089
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Non-financial assets and liabilities are recognized at fair value subsequent to initial recognition when they are deemed to be other-than-temporarily impaired. The Company periodically re-evaluates the original assumptions and rationale utilized in the establishment of the carrying value and estimated lives of its non-financial assets and liabilities. The criteria used for these evaluations include Management’s estimate of the asset’s continuing ability to generate positive cash flow in future periods as well as the strategic significance of any asset to the Company’s business objectives. If assets are considered to be impaired, the respective charge recognized is equal to the amount by which the carrying value of the assets exceeds the fair value of the assets, which is determined by applicable market prices when available or other methods by utilizing unobservable inputs (Level 3) including a discounted cash flow model.
Based on Management's assessment, during the six months ended June 30, 2014, the Company recognized impairment charges of $10.7 million related to the developed technology for the PCM® device acquired from Cervitech in 2009 and $2.2 million in leasehold improvement write-offs associated with exiting a majority of the leased square footage at its New Jersey location. Refer to Note 5, Goodwill and Intangible Assets and Note 10, Restructuring Charges, respectively, for further discussion on each transaction.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	Goodwill and Intangible Assets
	Goodwill and intangible assets consisted of the following (in thousands, except years):
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	June 30, 2014:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	51,620	$	(24,925	)	$	26,695
	Manufacturing know-how and trade secrets	12		21,988		(10,809		)	11,179
	Trade name and trademarks	11		9,500		(3,810		)	5,690
	Customer relationships	8		43,193		(22,085		)	21,108
	Total intangible assets subject to amortization	10		$	126,301	$	(61,629	)	$	64,672
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,637
	Total goodwill and intangible assets, net								$	229,949
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	December 31, 2013:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	62,328	$	(21,359	)	$	40,969
	Manufacturing know-how and trade secrets	12		21,997		(9,890		)	12,107
	Trade name and trademarks	11		9,500		(3,317		)	6,183
	Customer relationships	8		43,871		(19,784		)	24,087
	Total intangible assets subject to amortization	10		$	137,696	$	(54,350	)	$	83,346
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,944
	Total goodwill and intangible assets, net								$	248,930
	Total expense related to the amortization of intangible assets was $3.5 million and $4.9 million for the three months ended June 30, 2014 and 2013, respectively, and $7.5 million and $9.3 million for the six months ended June 30, 2014 and 2013, respectively. In-process research and development will be amortized beginning on the regulatory approval date of the respective acquired products and will be amortized over the estimated useful life determined at that time.
	During the three months ended June 30, 2014, the Company recorded an impairment charge of $10.7 million related to the developed technology for the PCM device acquired from Cervitech in 2009. The primary factor contributing to this impairment charge was the reduction in Management’s estimates of current and future revenue and the related cash flows due to updated views of the competitive and regulatory landscape in the cervical market.
	Total future amortization expense related to intangible assets subject to amortization at June 30, 2014 is set forth in the table below (in thousands):
	Remaining 2014	$	6,109
	2015	11,723
	2016	11,248
	2017	8,895
	2018	7,863
	2019	6,509
	Thereafter through 2026	12,325
	Total future amortization expense	$	64,672

Senior_Convertible_Notes

Senior Convertible Notes	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Senior Convertible Notes	'
	Senior Convertible Notes
	The carrying values of the Company’s Senior Convertible Notes are as follows (in thousands):
		June 30, 2014			December 31, 2013
	2.75% Senior Convertible Notes due 2017:
	Principal amount	$	402,500		$	402,500
	Unamortized debt discount	(49,231		)	(56,440		)
	Senior Convertible Notes due 2017, net of unamortized discount	$	353,269		$	346,060
	2.75% Senior Convertible Notes due 2017
	In June 2011, the Company issued $402.5 million principal amount of Senior Convertible Notes with a stated interest rate of 2.75% and a maturity date of July 1, 2017 (the "2017 Notes"). The net proceeds from the offering, after deducting initial purchasers’ discounts and costs directly related to the offering, were approximately $359.2 million. The 2017 Notes may be settled in cash, stock, or a combination thereof, solely at the Company’s discretion. It is the Company’s current intent and policy to settle all conversions through combination settlement, which involves repayment of an amount of cash equal to the principal amount and any excess of the conversion value over the principal amount in shares of common stock. The initial conversion rate of the 2017 Notes is 23.7344 shares per $1,000 principal amount, which is equivalent to a conversion price of approximately $42.13 per share, subject to adjustments. Interest on the 2017 Notes began accruing upon issuance and is payable semi-annually on January 1st and July 1st, beginning January 1, 2012.
	Prior to January 1, 2017, holders may convert their 2017 Notes only under the following conditions: (a) during any calendar quarter beginning October 1, 2011, if the reported sale price of the Company’s common stock for at least 20 days out of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than 130% of the conversion price on each applicable trading day; (b) during the five business day period in which the trading price of the 2017 Notes falls below 98% of the product of (i) the last reported sale price of the Company’s common stock and (ii) the conversion rate on that date; and (c) upon the occurrence of specified corporate events, as defined in the 2017 Notes. From January 1, 2017 and until the close of business on the second scheduled trading day immediately preceding July 1, 2017, holders may convert their 2017 Notes at any time (regardless of the foregoing circumstances). The Company may not redeem the 2017 Notes prior to maturity. Other than restrictions relating to certain fundamental changes and consolidations, mergers or asset sales and customary anti-dilution adjustments, the 2017 Notes do not contain any financial covenants and do not restrict the Company from paying dividends or issuing or repurchasing any of its other securities.
	In accordance with authoritative guidance, $49.3 million was recorded in stockholders' equity, and $88.9 million of debt discount was recorded during 2011. The debt discount is being recognized as interest expense using an effective interest rate of 8.0% over the term of the 2017 Notes.
	The interest expense recognized on the 2017 Notes during the three months ended June 30, 2014 includes $2.8 million and $3.6 million for the contractual coupon interest and the accretion of the debt discount, respectively. The interest expense recognized on the 2017 Notes during the six months ended June 30, 2014 includes $5.5 million and $7.2 million for the contractual coupon interest and the accretion of the debt discount, respectively. During the three months ended June 30, 2013, interest expense recognized on the 2017 Notes includes $2.8 million and $3.4 million for the contractual coupon interest and the accretion of the debt discount, respectively. The interest expense recognized on the 2017 Notes during the six months ended June 30, 2013 includes $5.5 million and $6.7 million for the contractual coupon interest and the accretion of the debt discount, respectively.
	In connection with the offering of the 2017 Notes, the Company entered into a convertible note hedge transaction (the "2017 Hedge") with the initial purchasers and/or their affiliates (the "2017 Counterparties") entitling the Company to purchase up to 9,553,096 shares of the Company’s common stock at an initial stock price of $42.13 per share, each of which is subject to adjustment. The cost of the 2017 Hedge was $80.1 million. In accordance with authoritative guidance, the derivative asset was assessed at a fair value and recorded in stockholders’ equity since the financial instruments were indexed to the Company's own stock. The 2017 Hedge expires on July 1, 2017. The 2017 Hedge is expected to reduce the potential equity dilution upon conversion of the 2017 Notes if the daily volume-weighted average price per share of the Company’s common stock exceeds the strike price of the 2017 Hedge.
	In addition, the Company sold warrants to the 2017 Counterparties to acquire up to 477,654 shares of the Company’s Series A Participating Preferred Stock (the "2017 Warrants"), at an initial strike price of $988.51 per share, subject to adjustment. Each share of Series A Participating Preferred Stock is convertible into 20 shares of the Company’s common stock, or up to 9,553,080 common shares. The 2017 Warrants expire on various dates from September 2017 through January 2018 and may be settled in cash or net shares. The Company received $47.9 million in cash proceeds from the sale of the 2017 Warrants, which has been recorded as an increase in additional paid-in-capital. The 2017 Warrants could have a dilutive effect on the Company’s earnings per share to the extent that the price of the Company’s common stock during a given measurement period exceeds the strike price of the 2017 Warrants.

StockBased_Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	Stock-Based Compensation
	Under the 2004 Amended and Restated Equity Incentive Plan, as amended (the "2004 EIP"), the Company had the ability to grant stock options, stock appreciation rights, restricted stock units, restricted stock awards, performance awards, and deferred stock awards. Effective as of February 20, 2014 and pursuant to its terms, no further awards may be granted under the 2004 EIP; however, that plan continues to govern all awards previously issued under it (many of which remain outstanding). In March 2014, the Compensation Committee (the "Compensation Committee") of the Board of Directors of the Company adopted the 2014 Equity Incentive Plan of NuVasive, Inc. (the "2014 EIP"), which was approved by our stockholders at our 2014 Annual Meeting of Stockholders and provides the Company with the ability to grant various types of equity awards to its workforce. Additionally, the NuVasive, Inc. 2004 Employee Stock Purchase Plan, as amended (the "ESPP"), provides eligible employees with a means of acquiring equity in the Company through accumulated payroll deductions and at a discounted purchase price. Each of the 2004 EIP and the 2014 EIP allow for net share settlement upon vesting of certain equity awards (be it with respect to taxes or strike price owed). The Company accounts for any net share settlement transactions as a treasury share repurchase transaction whereby the cost of repurchasing shares is included in treasury stock and reported as a reduction in total equity when a repurchase occurs, and for tax related withholding obligations.
	The Company uses the Black-Scholes option-pricing model (the "Black-Scholes model") to value share-based employee stock option and purchase right awards and Monte Carlo simulations (the "Monte Carlo model") to value performance-based restricted stock units. The Company uses the stock price on the date of grant to value time-based restricted stock units. The determination of fair value of stock-based payment awards using the Black-Scholes model and the Monte Carlo model requires the use of certain estimates and assumptions that affect the reported amount of share-based compensation cost recognized in the condensed consolidated statements of operations. Among these cost-affecting estimates are the expected term of awards, estimated forfeitures, expected volatility of the Company’s stock price, expected dividends and the risk-free interest rate. In addition to these assumptions, performance-based conditions require the assessment of probability of achievement and correlation coefficients. The fair value of equity instruments that are expected to vest are recognized and amortized on an accelerated basis over the requisite service periods.
	The compensation cost that has been included in the statement of operations for all stock-based compensation arrangements was as follows (in thousands):
		Three Months Ended							Six Months Ended
		June 30,							June 30,
		2014			2013				2014			2013
	Sales, marketing and administrative expense	$	8,251		$	8,278			$	15,437		$	14,703
	Research and development expense	483			449				947			791
	Cost of goods sold	51			34				165			54
	Total stock-based compensation expense	$	8,785		$	8,761			$	16,549		$	15,548
	At June 30, 2014, there was $42.1 million of unamortized compensation expense for stock options, restricted stock units and performance-based restricted stock units to be recognized over the remaining vesting periods.
	Stock Options and Purchase Rights
	The weighted average assumptions used to estimate the fair value of stock purchase rights under the ESPP are as follows:
		Three Months Ended					Six Months Ended
		June 30,					June 30,
		2014		2013			2014			2013
	ESPP
	Volatility	44	%	57	%		46	%		58	%
	Expected term (years)	1.2		1.6			1.2			1.5
	Risk free interest rate	0.2	%	0.2	%		0.2	%		0.2	%
	Expected dividend yield	—	%	—	%		—	%		—	%
	The Company did not grant any stock options during the three and six months ended June 30, 2014 or 2013.
	The Company issued approximately 74,000 and 478,000 shares of common stock upon the exercise of stock options during the three and six months ended June 30, 2014, respectively, and issued approximately 177,000 shares of common stock upon the exercise of stock options during the year ended December 31, 2013.
	Restricted Stock Units
	Time-based restricted stock units ("RSUs") represent a right to receive shares of common stock at a future date determined in accordance with the terms and conditions of a participant's award agreement (issued under either the 2004 EIP or 2014 EIP). No exercise price or other monetary payment are required for receipt of RSUs or the shares issued in settlement of the respective awards (provided the tax withholding obligations nonetheless apply); instead, consideration is furnished in the form of the participant’s services to the Company. Time-based RSUs have graded vesting terms of up to four years. Total compensation cost for these awards is based on the fair value of the award on the date of grant. The Compensation Committee has granted performance-based restricted stock units ("PRSUs") to certain senior Company executives annually since 2012. Pursuant to the terms and conditions of the PRSUs, such executives earned shares in 2012 and 2013 based on the achievement of pre-defined performance criteria. Additionally, in February 2014, the Compensation Committee granted PRSUs (the "2014 PRSUs") with performance criteria measured by the Company’s total shareholder return ("TSR") and total revenue growth over the two-year performance period spanning calendar years 2014 and 2015, with each performance metric being weighted equally and determined independently. The Company’s two-year TSR is measured as the change in the Company’s stock price between the opening stock price for 2014 and December 31, 2015, with the latter price being measured as the fifteen trading-day trailing average of the Company's stock price as of December 31, 2015 (without adjusting for dividends). The target TSR is the median TSR of the companies comprising the Dow Jones Medical Devices Index. Should the Company's two-year TSR over such two-year period be in excess of the 90th percentile of the index, the eligible executives will earn a number of shares of Company stock equal to 250% of the target amount of the 2014 PRSUs being awarded for this goal. Conversely, no shares would be awarded if the Company’s two-year TSR is below the 30th percentile of the index; provided, however, that, if the Company’s TSR during the two-year performance period is more than 5%, then, notwithstanding the Company’s percentile ranking, the minimum 25% of the target amount of the 2014 PRSUs would be eligible for award. Revenue growth performance is measured as total revenue growth against the target revenue growth as determined by the Compensation Committee, measured over the two-year performance period spanning fiscal years 2014 and 2015. Should the Company achieve 185.7% of the target revenue growth goal over such two-year period, eligible executives will earn a number of shares of Company stock equal to 250% of the target amount of the 2014 PRSUs being awarded for this goal. Conversely, no shares would be awarded upon achievement of less than 28.6% of the target revenue growth goal. The number of shares achieved with respect to the 2014 PRSUs will be determined in or around January 2016, upon determination of the Company’s two-year TSR and total revenue growth over the two year performance period as compared to the respective targets. Once such number of shares is determined pursuant to the PRSU criteria, half of any such shares will vest on a date shortly after the date the Compensation Committee makes the determination regarding performance, and the remaining half will vest on the one-year anniversary of such determination date (e.g. in 2017), subject, in all cases, to continuous employment through each of the vesting dates and certain, limited vesting acceleration criteria (i.e., in the event of a change of control).
	The fair value of the 2014 PRSUs based on the TSR performance metric is measured on the date of grant using a Monte Carlo model and the associated expense is amortized over the three-year period from the date of grant. The fair value of the PRSUs based on the revenue growth performance metric is measured on the date of grant, considering a probability of achieving the specific goals, and expense is amortized over the three-year vesting period. The Company re-evaluates the probability of achieving the specific goals each reporting period and adjusts the related expense and dilution accordingly.
	The Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods on a cumulative basis in the period the estimated forfeiture rate changes. The Company considered its historical experience of pre-vesting forfeitures on RSUs by employee ("shareowner") rank as the basis to arrive at its estimated annual pre-vesting forfeiture rate of 0% to 8% per year for the three and six months ended June 30, 2014.
	The Company issued approximately 145,000 and 1,355,000 shares of common stock in settlement of RSUs and PRSUs upon their vesting during the three and six months ended June 30, 2014, respectively, and issued approximately 665,000 shares of common stock in settlement of RSUs and PRSUs upon their vesting during the year ended December 31, 2013.

Income_Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company recorded an income tax expense of $1.9 million for the three months ended June 30, 2014 and an income tax benefit of $13.2 million for the six months ended June 30, 2014. The Company recorded an income tax benefit of $0.1 million and $0.8 million for the three and six months ended June 30, 2013, respectively. The effective income tax rate for the six months ended June 30, 2014 was 37% and reflects an expected statutory tax benefit associated with the trademark litigation accrual and discrete benefits relating to disqualifying dispositions of qualified stock grants, reduced by U.S. permanent tax items primarily relating to stock-based compensation and non-deductible expenses. The effective income tax rate for the six months ended June 30, 2013 was 12% and reflected a discrete tax benefit of $0.9 million, or 13% of pre-tax loss, related to the 2012 federal research and development credit which was retrospectively reinstated in the six months ended June 30, 2013. The Company updates its annual effective income tax rate each quarter and if the estimated effective income tax rate changes, a cumulative adjustment is made.
	There were no material changes to the Company's unrecognized tax benefits and interest accrued related to unrecognized tax benefits during the six months ended June 30, 2014.
	The Company's globalization initiative, which involves establishing new international operations and entering into new intercompany transfer pricing arrangements, including the licensing of intangibles, was implemented in January 2014. The Company's financial results for the three and six months ended June 30, 2014 reflects the current impact of this initiative.

Business_Segment_Product_and_G

Business Segment, Product, and Geographic Information	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Business Segment, Product and Geographic Information	'
	Business Segment, Product and Geographic Information
	The Company’s business operates in one segment based upon the Company’s organizational structure, the way in which the operations are managed and evaluated by the chief operating decision maker and the lack of availability of discrete financial information.
	The company operates under three products lines for revenues; Spine Surgery Products, Biologics and Monitoring Service. The Company’s Spine Surgery Product line offerings, which include thoracolumbar product offerings, cervical product offerings and disposables, are primarily used to enable access to the spine and to perform restorative and fusion procedures in a minimally disruptive fashion. The Company’s Biologic product line offerings includes allograft (donated human tissue), FormaGraft®, a collagen synthetic product, Osteocel® Plus and Osteocel® Pro, an allograft cellular matrix containing viable mesenchymal stem cells, or MSCs, and AttraX®, a synthetic bone graft material, all used to aid the spinal fusion or bone healing process. The Company’s Monitoring Service offering includes IOM services. Revenue by product line offerings was as follows (in thousands):
		Three Months Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Spine Surgery Products	$	147,333	$	128,682	$	284,640	$	251,348
	Biologics	32,837		27,855		62,327		55,012
	Monitoring Service	10,507		9,161		21,205		18,842
	Total Revenue	$	190,677	$	165,698	$	368,172	$	325,202
	Revenue and property and equipment, net, by geographic area were as follows (in thousands):
		Revenue								Property and Equipment, Net
		Three Months Ended				Six Months Ended				June 30,		December 31,
		June 30,				June 30,
		2014		2013		2014		2013		2014		2013
	United States	$	167,077	$	151,425	$	325,470	$	297,646	$	110,625	$	109,458
	International (excludes Puerto Rico)	23,600		14,273		42,702		27,556		24,238		18,606
	Total	$	190,677	$	165,698	$	368,172	$	325,202	$	134,863	$	128,064

Restructuring_Charges_Notes

Restructuring Charges (Notes)	6 Months Ended
	Jun. 30, 2014
Restructuring and Related Activities [Abstract]	'
Restructuring and Related Activities Disclosure [Text Block]	'
	Restructuring Charges
	During the six months ended June 30, 2014, as part of a company-wide efficiency effort, the Company reduced its footprint on the east coast of the United States in order to match its current and projected business needs without adversely impacting its ability to deliver surgeon education and local customer fulfillment. The Company exited a majority of the leased square footage at its New Jersey location and made a decision to terminate the respective lease early at December 2017. As a result of the reduction in space, the Company recorded restructuring and associated impairment charges in the six months ended June 30, 2014 of approximately $6.4 million, primarily associated with future rental payments through December 31, 2017 and lease termination charges, which was offset by estimated future sublease income. The impairment charges also included the net impact of a $0.1 million gain from writing-off deferred rent liabilities and leasehold improvements. As of June 30, 2014, the total recorded liability associated with this early lease termination was $6.0 million. The charge is recorded within sales, marketing and administrative expense in the Condensed Consolidated Statements of Operations for the three and six months ended June 30, 2014. The current portion of the liability is recorded within accounts payable and accrued liabilities and the long-term portion is recorded within other long-term liabilities in the Condensed Consolidated Balance Sheets at June 30, 2014.

Contingencies

Contingencies	6 Months Ended
	Jun. 30, 2014
Contingencies [Abstract]	'
Contingencies	'
	Contingencies
	We are subject to potential liabilities under government regulations and various claims and legal actions that are pending or may be asserted. These matters arise in the ordinary course and conduct of our business. They include, for example, commercial, intellectual property, environmental, securities and employment matters. We intend to continue to defend ourselves vigorously in such matters. We regularly assess contingencies to determine the degree of probability and range of possible loss for potential accrual in our financial statements. An estimated loss contingency is accrued in our financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Based on our assessment, we have adequately accrued an amount for contingent liabilities currently in existence. The Company does not accrue amounts for liabilities that the Company considers immaterial to its overall financial position. Litigation is inherently unpredictable, and unfavorable resolutions could occur. As a result, assessing contingencies is highly subjective and requires judgment about future events. The amount of ultimate loss may exceed our current accruals, and it is possible that our cash flows or results of operations could be materially affected in any particular period by the unfavorable resolution of one or more of these contingencies.
	Legal Proceedings
	Medtronic Sofamor Danek USA, Inc. Litigation
	In August 2008, Warsaw Orthopedic, Inc., Medtronic Sofamor Danek USA, Inc. and other Medtronic related entities (collectively, "Medtronic") filed a patent infringement lawsuit against NuVasive in the United States District Court for the Southern District of California (the "Medtronic Litigation"), alleging that certain of NuVasive’s products or methods, including the XLIF® procedure, infringe, or contribute to the infringement of, twelve U.S. patents assigned or licensed to Medtronic. Three of the patents were later withdrawn by Medtronic, leaving nine purportedly infringed patents. NuVasive brought counterclaims against Medtronic alleging infringement of certain of NuVasive’s patents.
	The case has been administratively broken into serial phases. The first phase of the case included three Medtronic patents and one NuVasive patent. Trial on the first phase of the case concluded on September 20, 2011 and a jury delivered an unfavorable verdict against NuVasive with respect to the three Medtronic patents and a favorable verdict with respect to the one NuVasive patent at hand. The jury awarded monetary damages of approximately $101.2 million to Medtronic, which includes lost profits and back royalties (the "2011 verdict"). Medtronic’s subsequent motion for a permanent injunction was denied by the District Court on January 26, 2012. On March 19, 2012, the District Court issued an order granting prejudgment interest with respect to the patent infringements determined in the 2011 verdict, and, on June 11, 2013, the District Court ruled on the respective ongoing royalty rates (the "June 2013 ruling"). On August 20, 2013, NuVasive and Medtronic filed their respective notices of appeal of such decisions, and the appeal is now proceeding before the U.S. Court of Appeals for the Federal Circuit. In addition, on March 19, 2012, in connection with these proceedings, the Company entered into an escrow arrangement and transferred $113.3 million of cash into a restricted escrow account to secure the amount of judgment, plus prejudgment interest, during pendency of the appeal. These funds are included in restricted cash and investments on the Company's June 30, 2014 condensed consolidated balance sheet.
	In accordance with the authoritative guidance on the evaluation of loss contingencies, during the three months ended September 30, 2011, the Company recorded an accrual of $101.2 million for the 2011 verdict. In addition, on sales subsequent to the 2011 verdict and through March 31, 2013, the Company accrued royalties at the royalty rates stated in the 2011 verdict, and, upon receiving the June 2013 ruling, the Company began accruing ongoing royalties on sales at the royalty rates stated in the June 2013 ruling, and recorded a charge of approximately $7.9 million to account for the difference between using the royalty rates stated in the 2011 verdict and those in the June 2013 ruling on sales through March 31, 2013. As a result of the June 2013 ruling, the Company will be required to escrow funds to secure accrued royalties, estimated at $25 million to date, as well as future ongoing royalties. The Company is also accruing post-judgment interest. With respect to the prejudgment interest award, the Company, based on its own assessment, as well as that of outside counsel, believes a reversal of the prejudgment interest award on appeal is probable, and, therefore - in accordance with authoritative guidance on the evaluation of loss contingencies - has not recorded an accrual for this amount, which is estimated to approximate $13 million. Additional damages (including interest) may still be awarded, and, as of June 30, 2014, the Company cannot estimate a range of additional potential loss.
	With respect to the favorable verdict delivered regarding the one NuVasive patent litigated to verdict, the jury awarded the Company monetary damages of approximately $0.7 million for reasonable royalty damages. In accordance with the authoritative guidance on the evaluation of gain contingencies, this amount has not been recorded at June 30, 2014. Additionally, the June 2013 ruling determined the ongoing royalty rate to be paid to the Company by Medtronic for its post-verdict sales of the one NuVasive patent. Consistent with the treatment afforded the $0.7 million damage award, no amount has been recorded for royalty revenue as of June 30, 2014.
	The second phase of the case involved one Medtronic cervical plate patent. On April 25, 2013, NuVasive and Medtronic entered into a settlement agreement fully resolving the second phase of the case. The settlement also removes from the case the cervical plate patent that was part of the first phase. As part of the settlement, NuVasive received a broad license to practice (i) the Medtronic patent that was the sole subject of the second phase of the litigation, (ii) the Medtronic patent that was part of the first phase of the litigation, and (iii) each of the Medtronic patent families that collectively represent the vast majority of Medtronic's patent rights related to cervical plate technology. In exchange for these license rights, NuVasive made a one-time payment to Medtronic of $7.5 million, which amount will be fully offset against any damage award ultimately determined to be owed by NuVasive in connection with a final resolution of the first phase of the litigation. In addition, Medtronic will receive a royalty on certain cervical plate products sold by NuVasive, including the Helix® and Gradient® lines of products. As a result of this settlement, all current patent disputes between the parties related to cervical plate technology have been resolved.
	In August 2012, Medtronic filed additional patent claims in the U.S. District Court for the Northern District of Indiana alleging that various NuVasive spinal implants (including its CoRoent® XL family of spinal implants) infringe Medtronic's U.S. Patent No. 8,021,430, that NuVasive's Osteocel® Plus bone graft product infringes Medtronic's U.S. Patent No. 5,676,146, and that NuVasive's XLIF® procedure and use of MaXcess IV retractor during the XLIF procedure infringe methodology claims of Medtronic's U.S. Patent No. 8,251,997. The case, which is referred to herein as the third phase of the Medtronic litigation, was later transferred to the Southern District of California, and, on March 7, 2013, NuVasive counterclaimed alleging infringement by Medtronic of Nuvasive's U.S. Patent Nos. 8,000,782 (systems and related methods for performing surgical procedures), 8,005,535 (systems and related methods for performing surgical procedures), 8,016,767 (a surgical access system including a tissue distraction assembly and a tissue retraction assembly), 8,192,356 (a system for accessing a surgical target site and related methods, involving an initial distraction system, among other things), 8,187,334 (spinal fusion implant), 8,361,156 (spinal fusion implant), D652,922 (dilator design), and D666,294 (dilator design). On July 25, 2013, Medtronic amended its complaint to add a charge of infringement of its U.S. Patent No. 8,444,696. The District Court has stayed litigation of a number of Medtronic and NuVasive patents currently subject to reexamination or review proceedings conducted by the Patent Office. No trial date has been set, but trial is anticipated to be scheduled for the second quarter of 2015 on Medtronic's U.S. Patent No. 5,676,146 and NuVasive's U.S. Patent No. D652,922. Trial on this third phase of the case is anticipated to begin in early 2015. At June 30, 2014, the probable outcome of this litigation cannot be determined, nor can the Company estimate a range of potential loss. In accordance with the authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual related to this litigation.
	Trademark Infringement Litigation
	In September 2009, Neurovision Medical Products, Inc. ("NMP") filed suit against NuVasive in the U.S. District Court for the Central District of California (Case No. 2:09-cv-06988-R-JEM) alleging trademark infringement and unfair competition. NMP sought cancellation of NuVasive’s "NeuroVision" trademark registrations, injunctive relief and damages based on NMP’s common law use of the "NeuroVision" mark. On November 23, 2009, the Company denied the allegations in NMP’s complaint. The matter was tried in October 2010 and an unfavorable jury verdict was delivered against the Company relating to its use of the NeuroVision trade name. The verdict awarded damages to NMP of $60.0 million, which was upheld in a January 2011 judgment ordered by the District Court. The Company appealed the judgment, and, on September 10, 2012, the Court of Appeals reversed and vacated the District Court judgment and ordered the case back to the District Court for a new trial before a different judge. On October 5, 2012, the case was reassigned to a new District Court judge for re-trial of the matter. During pendency of the appeal, the Company was required to escrow funds totaling $62.5 million to secure the amount of the judgment, plus interest, attorneys’ fees and costs. As a result of the reversal of the judgment, the full $62.5 million was released from escrow and returned to the Company. Re-trial of this matter began on March 25, 2014, and on April 3, 2014, the jury returned a verdict in favor of NMP on its claims against NuVasive in the amount of $30 million. Judgment has not been entered, and a hearing on NuVasive's affirmative defenses and motions for judgment as a matter of law and for a new trial, as well as NMP's motions for cancellation of trademark and a permanent injunction is anticipated to occur in August 2014. At June 30, 2014, the April 3, 2014 jury verdict represents a probable loss that can reasonably be determined. Accordingly, in accordance with the authoritative guidance on the evaluation of loss contingencies, the Company has recorded a $30 million liability related to this litigation.
	Securities Litigation
	On August 28, 2013, a purported securities class action lawsuit was filed by Danny Popov in the United States District Court for the Southern District of California naming NuVasive and certain of its current and former executive officers for allegedly making false and materially misleading statements regarding the Company's business and financial results, specifically relating to the purported improper submission of false claims to Medicare and Medicaid. The complaint asserts a putative class period stemming from October 22, 2008 to July 30, 2013. The complaint alleges violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 promulgated thereunder and seeks unspecified monetary relief, interest, and attorneys’ fees. On February 13, 2014, the lead plaintiff filed an Amended Class Action Complaint for Violations of the Federal Securities Laws. On March 28, 2014, the Company filed a motion to dismiss the Amended Class Action Complaint for Violations of the Federal Securities Laws, which has been fully briefed and taken under submission by the Court. The Company intends to vigorously defend against this action. At June 30, 2014, the probable outcome of this litigation cannot be determined, nor can the Company estimate a range of potential loss. In accordance with authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual related to this litigation.

Regulatory_Matter_Notes

Regulatory Matter (Notes)	6 Months Ended
	Jun. 30, 2014
Regulatory Matter [Abstract]	'
Regulatory Matter [Text Block]	'
	Regulatory Matter
	During the three months ended June 30, 2013, the Company received a federal administrative subpoena from the Office of the Inspector General of the U.S. Department of Health and Human Services ("OIG") in connection with an investigation into possible false or otherwise improper claims submitted to Medicare and Medicaid. The subpoena seeks discovery of documents for the period January 2007 through April 2013. The Company is working with the OIG to understand the scope of the subpoena and to provide the requested documents. The Company intends to fully cooperate with the OIG's request. At June 30, 2014, the Company is unable to determine the potential financial impact, if any, that will result from this investigation.

Description_of_Business_and_Ba1

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business	'
	Description of Business.    NuVasive, Inc. (the "Company" or "NuVasive") was incorporated in Delaware on July 21, 1997, and began commercializing its products in 2001. The Company is focused on developing minimally-disruptive surgical products and procedurally-integrated solutions for the spine. NuVasive's principal product offering includes a minimally-disruptive surgical platform called "Maximum Access Surgery", or "MAS®", as well as an offering of biologics, cervical and motion preservation products. The MAS platform combines three categories of solutions that collectively minimize soft tissue disruption during spine fusion surgery, provide maximum visualization and are designed to enable reproducible outcomes for the surgeon. The platform includes the Company's proprietary nerve monitoring systems (which include software-driven nerve detection and avoidance systems (called "NVM5®" and "NVJJB") and accompanying intra-operative monitoring ("IOM") support); MaXcess®, an integrated split-blade retractor system; and a wide variety of specialized implants. The individual components of NuVasive's MAS platform, and many of the Company's products, can also be used in open or traditional spine surgery. The Company continues to focus significant research and development efforts to expand its MAS product platform and advance the applications of its unique technology into procedurally integrated surgical solutions. The Company dedicates significant resources toward training spine surgeons on its unique technology and products.
	The Company's primary business model is to loan its MAS systems to surgeons and hospitals who purchase implants, biologics, and disposables for use in individual procedures. In addition, for larger customers, the Company places its proprietary nerve monitoring systems, MaXcess and surgical instrument sets with hospitals for an extended period at no up-front cost to them. The Company also offers a range of bone allograft in patented saline packaging, disposables and spine implants, which include its branded CoRoent® products and fixation devices such as rods, plates and screws. Implants, biologics and disposables are shipped from the Company’s inventories. The Company sells an immaterial quantity of MAS instrument sets, MaXcess and nerve monitoring systems to hospitals.
Basis of Presentation and Principles of Consolidation	'
	Basis of Presentation and Principles of Consolidation.    The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its majority-owned or controlled subsidiaries, collectively referred to as either NuVasive or the Company. The Company translates the financial statements of its foreign subsidiaries using end-of-period exchange rates for assets and liabilities and average exchange rates during each reporting period for results of operations. When there is a portion of equity in an acquired subsidiary not attributable, directly or indirectly, to the respective parent entity, the Company records the fair value of the noncontrolling interests at the acquisition date and classifies the amounts attributable to noncontrolling interests separately in equity in the Company’s condensed consolidated financial statements. Any subsequent changes in a parent’s ownership interest while the parent retains its controlling financial interest in its subsidiary are accounted for as equity transactions. All significant intercompany balances and transactions have been eliminated in consolidation.
	The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the "SEC"). Pursuant to these rules and regulations, the Company has condensed or omitted certain information and footnote disclosures it normally includes in its annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Operating results for the three and six months ended June 30, 2014 are not necessarily indicative of the results that may be expected for any other interim period or for the full year. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2013 included in NuVasive’s Annual Report on Form 10-K filed with the SEC. In the opinion of Management, the condensed consolidated financial statements include all adjustments that are of a normal and recurring nature that are necessary for the fair presentation of the Company's financial position and of the results of operations and cash flows for the periods presented.

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Computation of basic and diluted earnings per share	'
	The following table sets forth the computation of basic and diluted earnings or (loss) per share attributable to the Company (in thousands, except per share data):
		Three Months Ended							Six Months Ended
		June 30,							June 30,
		2014				2013			2014			2013
	Numerator:
	Net loss attributable to the Company	$	(4,088	)		$	(6,469	)	$	(22,364	)	$	(5,618	)
	Denominator for basic and diluted net income per share:
	Weighted average common shares outstanding for basic	46,832				44,412			46,320			44,220
	Weighted average common shares outstanding for diluted	46,832				44,412			46,320			44,220
	Basic net loss per share attributable to the Company	$	(0.09	)		$	(0.15	)	$	(0.48	)	$	(0.13	)
	Diluted net loss per share attributable to the Company	$	(0.09	)		$	(0.15	)	$	(0.48	)	$	(0.13	)
Anti-dilutive common stock equivalents not included in calculation of net income per diluted share	'
	The following weighted outstanding common stock equivalents were not included in the calculation of net income (loss) per diluted share because their effects were anti-dilutive (in thousands):
		Three Months Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014		2013
	Stock options, ESPP shares and restricted stock units	8,949			7,953			8,409		7,518
	Warrants	9,553			14,641			9,553		14,667
	Senior Convertible Notes	9,553			9,553			9,553		10,232
	Total	28,055			32,147			27,515		32,417

Business_Combinations_Tables

Business Combinations (Tables)	6 Months Ended
	Jun. 30, 2014
Business Combination, Description [Abstract]	'
Summary of assets and liabilities included in the accompanying consolidated balance sheet	'
	Total assets and liabilities of Progentix included in the accompanying condensed consolidated balance sheet are as follows (in thousands):
		June 30, 2014		December 31, 2013
	Total current assets	$	549	$	580
	Identifiable intangible assets, net	14,169		14,403
	Goodwill	12,654		12,654
	Other long-term assets	4		7
	Accounts payable and accrued expenses	522		403
	Deferred tax liabilities, net	2,770		2,770
	Noncontrolling interests	8,648		9,086
Reconciliation of equity (net assets) attributable to the noncontrolling interests	'
	The following is a reconciliation of equity (net assets) attributable to the noncontrolling interests (in thousands):
		Six Months Ended June 30,
		2014		2013
	Noncontrolling interests at beginning of period	$	9,086	$	10,003
	Less: Net loss attributable to the noncontrolling interests prior to reclassification from mezzanine to equity	—		514
	Less: Net loss attributable to the noncontrolling interests subsequent to reclassification from mezzanine to equity	438		—
	Noncontrolling interests at end of period	$	8,648	$	9,489

Financial_Instruments_and_Fair1

Financial Instruments and Fair Value Measurements Fair Value Table (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Table [Abstract]	'
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	'
	The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):
		Total			Quoted Price in		Significant Other		Significant
					Active Market		Observable Inputs		Unobservable
					(Level 1)		(Level 2)		Inputs (Level 3)
	June 30, 2014:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	55,092		$	55,092	$	—	$	—
	Certificates of deposit	869			869		—		—
	Corporate notes	137,075			—		137,075		—
	Commercial paper	10,000			—		10,000		—
	U.S. government treasury securities	49,366			49,366		—		—
	Securities of government-sponsored entities	124,806			—		124,806		—
	Total cash equivalents, marketable securities and restricted investments	$	377,208		$	105,327	$	271,881	$	—
	Contingent Consideration:
	Acquisition-related liabilities, current	$	(648	)	$	—	$	—	$	(648	)
	Total contingent consideration	$	(648	)	$	—	$	—	$	(648	)
	December 31, 2013:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	72,514		$	72,514	$	—	$	—
	Certificates of deposit	1,116			1,116		—		—
	Corporate notes	103,946			—		103,946		—
	Commercial paper	19,973			—		19,973		—
	U.S. government treasury securities	52,390			52,390		—		—
	Securities of government-sponsored entities	118,250			—		118,250		—
	Total cash equivalents, marketable securities and restricted investments	$	368,189		$	126,020	$	242,169	$	—
	Contingent Consideration:
	Acquisition-related liabilities, current	$	(616	)	$	—	$	—	$	(616	)
	Acquisition-related liabilities, non-current	$	(596	)	$	—	$	—	$	(596	)
	Total contingent consideration	$	(1,212	)	$	—	$	—	$	(1,212	)
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block]	'
	The following table sets forth the changes in the estimated fair value of the Company’s liabilities measured on a recurring basis using significant unobservable inputs (Level 3) (in thousands):
		Six Months Ended June 30,
		2014			2013
	Fair value measurement at beginning of period	$	1,212		$	1,074
	Change in fair value measurement included in operating expenses	44			15
	Contingent consideration paid or settled	(608		)	—
	Fair value measurement at end of period	$	648		$	1,089

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and intangible assets	'
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	December 31, 2013:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	62,328	$	(21,359	)	$	40,969
	Manufacturing know-how and trade secrets	12		21,997		(9,890		)	12,107
	Trade name and trademarks	11		9,500		(3,317		)	6,183
	Customer relationships	8		43,871		(19,784		)	24,087
	Total intangible assets subject to amortization	10		$	137,696	$	(54,350	)	$	83,346
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,944
	Total goodwill and intangible assets, net								$	248,930
	Goodwill and intangible assets consisted of the following (in thousands, except years):
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	June 30, 2014:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	51,620	$	(24,925	)	$	26,695
	Manufacturing know-how and trade secrets	12		21,988		(10,809		)	11,179
	Trade name and trademarks	11		9,500		(3,810		)	5,690
	Customer relationships	8		43,193		(22,085		)	21,108
	Total intangible assets subject to amortization	10		$	126,301	$	(61,629	)	$	64,672
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,637
	Total goodwill and intangible assets, net								$	229,949
Future amortization expense related to intangible assets	'
	Total future amortization expense related to intangible assets subject to amortization at June 30, 2014 is set forth in the table below (in thousands):
	Remaining 2014	$	6,109
	2015	11,723
	2016	11,248
	2017	8,895
	2018	7,863
	2019	6,509
	Thereafter through 2026	12,325
	Total future amortization expense	$	64,672

Senior_Convertible_Notes_Table

Senior Convertible Notes (Tables)	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Net carrying amount of the debt component	'
	The carrying values of the Company’s Senior Convertible Notes are as follows (in thousands):
		June 30, 2014			December 31, 2013
	2.75% Senior Convertible Notes due 2017:
	Principal amount	$	402,500		$	402,500
	Unamortized debt discount	(49,231		)	(56,440		)
	Senior Convertible Notes due 2017, net of unamortized discount	$	353,269		$	346,060

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP	'
	The weighted average assumptions used to estimate the fair value of stock purchase rights under the ESPP are as follows:
		Three Months Ended					Six Months Ended
		June 30,					June 30,
		2014		2013			2014			2013
	ESPP
	Volatility	44	%	57	%		46	%		58	%
	Expected term (years)	1.2		1.6			1.2			1.5
	Risk free interest rate	0.2	%	0.2	%		0.2	%		0.2	%
	Expected dividend yield	—	%	—	%		—	%		—	%
Compensation costs included in statement of income for all stock-based compensation arrangements	'
	The compensation cost that has been included in the statement of operations for all stock-based compensation arrangements was as follows (in thousands):
		Three Months Ended							Six Months Ended
		June 30,							June 30,
		2014			2013				2014			2013
	Sales, marketing and administrative expense	$	8,251		$	8,278			$	15,437		$	14,703
	Research and development expense	483			449				947			791
	Cost of goods sold	51			34				165			54
	Total stock-based compensation expense	$	8,785		$	8,761			$	16,549		$	15,548
	At June 30, 2014, there was $42.1 million of unamortized compensation expense for stock options, restricted stock units and performance-based restricted stock units to be recognized over the remaining vesting periods.

Business_Segment_Product_and_G1

Business Segment, Product, and Geographic Information (Tables)	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Revenue from External Customers by Products and Services	'
	Revenue by product line offerings was as follows (in thousands):
		Three Months Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Spine Surgery Products	$	147,333	$	128,682	$	284,640	$	251,348
	Biologics	32,837		27,855		62,327		55,012
	Monitoring Service	10,507		9,161		21,205		18,842
	Total Revenue	$	190,677	$	165,698	$	368,172	$	325,202
Schedule of Revenue and Net Property and Equipment by Geographical Areas [Table Text Block]	'
	Revenue and property and equipment, net, by geographic area were as follows (in thousands):
		Revenue								Property and Equipment, Net
		Three Months Ended				Six Months Ended				June 30,		December 31,
		June 30,				June 30,
		2014		2013		2014		2013		2014		2013
	United States	$	167,077	$	151,425	$	325,470	$	297,646	$	110,625	$	109,458
	International (excludes Puerto Rico)	23,600		14,273		42,702		27,556		24,238		18,606
	Total	$	190,677	$	165,698	$	368,172	$	325,202	$	134,863	$	128,064

Description_of_Business_and_Ba2

Description of Business and Basis of Presentation Change in Accounting Estimate (Details) (USD $)	3 Months Ended	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014
Change in Accounting Estimate [Line Items]	'	'
Document Period End Date	'	30-Jun-14
Corporate office consolidation [Member]	'	'
Change in Accounting Estimate [Line Items]	'	'
Depreciation Affect of Change in Estimate	$0.50	'
Depreciation Affect of Change in Estimate - Full Year Impact	'	4.1
International surgical instrument sets [Member]	'	'
Change in Accounting Estimate [Line Items]	'	'
Depreciation Affect of Change in Estimate	0.7	1.4
Depreciation Affect of Change in Estimate - Full Year Impact	'	$2.80

Description_of_Business_and_Ba3

Description of Business and Basis of Presentation Comprehensive Income (Loss) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Cumulative Translation Adjustments [Abstract]	'	'
Translation Adjustment Functional to Reporting Currency, Net of Tax	$1.20	$3.30

Description_of_Business_and_Ba4

Description of Business and Basis of Presentation Exit or Disposal Costs (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Restructuring and Related Activities [Abstract]	'
Asset Impairment Charges	$2.20

Description_of_Business_and_Ba5

Description of Business and Basis of Presentation Inventory Reserves (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Inventory Valuation Reserves	$23.30	$21.90

Net_Income_Per_Share_Computati

Net Income Per Share Computation of Basic and Diluted Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator:	'	'	'	'
Net loss attributable to the Company	($4,088)	($6,469)	($22,364)	($5,618)
Denominator for basic and diluted net income per share:	'	'	'	'
Weighted average common shares outstanding for basic (in shares)	46,832	44,412	46,320	44,220
Weighted average common shares outstanding for diluted (in shares)	46,832	44,412	46,320	44,220
Earnings Per Share, Basic	($0.09)	($0.15)	($0.48)	($0.13)
Earnings Per Share, Diluted	($0.09)	($0.15)	($0.48)	($0.13)

Net_Income_Per_Share_Antidilut

Net Income Per Share Anti-dilutive Common Stock Equivalents Not Included in Calculation of Net Income Per Diluted Share (Details)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Computation of basic and diluted earnings per share	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share	28,055	32,147	27,515	32,417
Stock Options and RSUs [Member]	'	'	'	'
Computation of basic and diluted earnings per share	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share	8,949	7,953	8,409	7,518
Warrants [Member]	'	'	'	'
Computation of basic and diluted earnings per share	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share	9,553	14,641	9,553	14,667
Senior Convertible Notes [Member]	'	'	'	'
Computation of basic and diluted earnings per share	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share	9,553	9,553	9,553	10,232

Business_Combinations_Details

Business Combinations (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Components of total assets and liabilities of Progentix	'	'
Noncontrolling Interest in Variable Interest Entity	$8,648	$9,086
Progentix Orthobiology [Member]	'	'
Components of total assets and liabilities of Progentix	'	'
Variable Interest Entity Consolidated Carrying Amount Current Assets Net	549	580
Variable Interest Entity Consolidated Carrying Amount Finite And Indefinite Lived Intangible Assets Net	14,169	14,403
Variable Interest Entity Consolidated Carrying Amount Goodwill	12,654	12,654
Variable Interest Entity Consolidated Carrying Amount Other Long Term Assets Net	4	7
Variable Interest Entity Consolidated Carrying Amount Current Liabilities Net	522	403
Variable Interest Entity Consolidated Carrying Amount Deferred Tax Liabilities Net	$2,770	$2,770

Reconciliation_of_Equity_Net_A

Reconciliation of Equity (Net Assets) Attributable to the Noncontrolling Interests (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of equity (net assets) attributable to the noncontrolling interests	'	'	'	'
Noncontrolling interests at beginning of period	'	'	'	$10,003
Non-redeembable Noncontrolling Interest in Variable Interest Entity	8,648	'	8,648	'
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	'	259	0	514
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	182	'	438	0
Noncontrolling interests at end of period	'	9,489	'	9,489
Non-redeembable Noncontrolling Interest in Variable Interest Entity	'	'	$9,086	'

Business_Combinations_Details_

Business Combinations (Details Textual) (Progentix Orthobiology [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2009
Preferred Stock Purchase Agreement [Member]	'
Business Combinations (Textual) [Abstract]	'
Percentage of ownership Interests acquired	40.00%
Cash payment on purchase of outstanding shares	$10
Percentage of minority interest represented by preferred stock	18.00%
Percentage of cumulative dividend	'cumulative 8% dividend
Percentage of cumulative dividend, percent	8.00%
Option Purchase Agreement [Member]	'
Business Combinations (Textual) [Abstract]	'
Term of distribution agreement years	'10 years

Financial_Instruments_and_Fair2

Financial Instruments and Fair Value Measurements - Composition of Marketable Securities (Details) (USD $)	6 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	322,152	295,638
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	119	102
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	155	65
Available-for-sale Securities, Fair Value	322,116	295,675
Restricted Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	78,323	72,399
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	47	20
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	23	22
Available-for-sale Securities, Fair Value	78,347	72,397
Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	140,833	143,425
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	53	39
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	37	15
Available-for-sale Securities, Fair Value	140,849	143,449
Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	102,996	79,814
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	19	43
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	95	28
Available-for-sale Securities, Fair Value	102,920	79,829
Certificates of deposit [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	869	833
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	0	0
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	0	0
Available-for-sale Securities, Fair Value	869	833
Certificates of deposit [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	0	283
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	0	0
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	0	0
Available-for-sale Securities, Fair Value	0	283
Corporate notes [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	79,198	71,611
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	20	23
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	35	6
Available-for-sale Securities, Fair Value	79,183	71,628
Corporate notes [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	57,940	32,309
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	11	23
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	59	14
Available-for-sale Securities, Fair Value	57,892	32,318
Commercial paper [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	10,000	19,973
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	0	0
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	0	0
Available-for-sale Securities, Fair Value	10,000	19,973
U.S. government treasury securities [Member] | Restricted Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	47,823	43,274
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	43	16
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	2	6
Available-for-sale Securities, Fair Value	47,864	43,284
U.S. government treasury securities [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	1,500	7,603
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	2	2
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	0	0
Available-for-sale Securities, Fair Value	1,502	7,605
U.S. government treasury securities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	'	1,500
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	'	1
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	'	0
Available-for-sale Securities, Fair Value	'	1,501
Securities of government-sponsored entities [Member] | Restricted Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	30,500	29,125
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	4	4
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	21	16
Available-for-sale Securities, Fair Value	30,483	29,113
Securities of government-sponsored entities [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	49,266	43,405
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	31	14
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	2	9
Available-for-sale Securities, Fair Value	49,295	43,410
Securities of government-sponsored entities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities, Cost	45,056	45,722
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax	8	19
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax	36	14
Available-for-sale Securities, Fair Value	45,028	45,727
Minimum [Member] | Certificates of deposit [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'
Minimum [Member] | Corporate notes [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'
Minimum [Member] | U.S. government treasury securities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'
Minimum [Member] | Securities of government-sponsored entities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'	'1 year
Maximum [Member] | Certificates of deposit [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'1 year
Maximum [Member] | Certificates of deposit [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'2 years	'
Maximum [Member] | Corporate notes [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'1 year
Maximum [Member] | Corporate notes [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'2 years	'
Maximum [Member] | Commercial paper [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'1 year
Maximum [Member] | U.S. government treasury securities [Member] | Restricted Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'2 years	'2 years
Maximum [Member] | U.S. government treasury securities [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'1 year
Maximum [Member] | U.S. government treasury securities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'2 years	'
Maximum [Member] | Securities of government-sponsored entities [Member] | Restricted Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'2 years	'2 years
Maximum [Member] | Securities of government-sponsored entities [Member] | Short-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'1 year	'1 year
Maximum [Member] | Securities of government-sponsored entities [Member] | Long-term Investments [Member]	'	'
Composition of marketable securities	'	'
Available-for-sale Securities Contractual Maturity	'	'2 years

Financial_Instruments_and_Fair3

Financial Instruments and Fair Value Measurements - Fair Value of Assets and Liabilities (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'
Debt Instrument, Fair Value Disclosure	$458,900,000	'	$458,900,000	'	$439,300,000
Goodwill and Intangible Asset Impairment	10,708,000	0	10,708,000	0	'
Contingent Consideration:	'	'	'	'	'
Asset Impairment Charges	'	'	2,200,000	'	'
Fair value measurements on recurring basis [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	377,208,000	'	377,208,000	'	368,189,000
Contingent Consideration Fair Value Disclosure, Current	-648,000	'	-648,000	'	-616,000
Acquisition-related liabilities, non-current	'	'	'	'	-596,000
Contingent Consideration:	'	'	'	'	'
Acquisition-related liabilities	-648,000	'	-648,000	'	-1,212,000
Fair value measurements on recurring basis [Member] | Money Market Funds [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	55,092,000	'	55,092,000	'	72,514,000
Fair value measurements on recurring basis [Member] | Certificates of deposit [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	869,000	'	869,000	'	1,116,000
Fair value measurements on recurring basis [Member] | Corporate notes [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	137,075,000	'	137,075,000	'	103,946,000
Fair value measurements on recurring basis [Member] | Commercial paper [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	10,000,000	'	10,000,000	'	19,973,000
Fair value measurements on recurring basis [Member] | U.S. government treasury securities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	49,366,000	'	49,366,000	'	52,390,000
Fair value measurements on recurring basis [Member] | Securities of government-sponsored entities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	124,806,000	'	124,806,000	'	118,250,000
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	105,327,000	'	105,327,000	'	126,020,000
Contingent Consideration Fair Value Disclosure, Current	0	'	0	'	0
Acquisition-related liabilities, non-current	'	'	'	'	0
Contingent Consideration:	'	'	'	'	'
Acquisition-related liabilities	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | Money Market Funds [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	55,092,000	'	55,092,000	'	72,514,000
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | Certificates of deposit [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	869,000	'	869,000	'	1,116,000
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | Corporate notes [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | Commercial paper [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | U.S. government treasury securities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	49,366,000	'	49,366,000	'	52,390,000
Fair value measurements on recurring basis [Member] | Quoted price in active market (Level 1) [Member] | Securities of government-sponsored entities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	271,881,000	'	271,881,000	'	242,169,000
Contingent Consideration Fair Value Disclosure, Current	0	'	0	'	0
Acquisition-related liabilities, non-current	'	'	'	'	0
Contingent Consideration:	'	'	'	'	'
Acquisition-related liabilities	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | Money Market Funds [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | Certificates of deposit [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | Corporate notes [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	137,075,000	'	137,075,000	'	103,946,000
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | Commercial paper [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	10,000,000	'	10,000,000	'	19,973,000
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | U.S. government treasury securities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant other observable inputs (Level 2) [Member] | Securities of government-sponsored entities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	124,806,000	'	124,806,000	'	118,250,000
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Contingent Consideration Fair Value Disclosure, Current	-648,000	'	-648,000	'	-616,000
Acquisition-related liabilities, non-current	'	'	'	'	-596,000
Contingent Consideration:	'	'	'	'	'
Acquisition-related liabilities	-648,000	'	-648,000	'	-1,212,000
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | Money Market Funds [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | Certificates of deposit [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | Corporate notes [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | Commercial paper [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | U.S. government treasury securities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	0	'	0	'	0
Fair value measurements on recurring basis [Member] | Significant unobservable inputs (Level 3) [Member] | Securities of government-sponsored entities [Member]	'	'	'	'	'
Marketable Securities and Restricted Investments	'	'	'	'	'
Total marketable securities and restricted investments	$0	'	$0	'	$0

Financial_Instruments_and_Fair4

Financial Instruments and Fair Value Measurements (Details Textual)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	USD ($)	Immaterial Acquisition 2012 [Member]	Immaterial Acquisition 2012 [Member]
	Milestone	USD ($)	EUR (€)
Investments, Debt and Equity Securities [Abstract]	'	'	'
Impairment charges recorded for earnings	$0	'	'
Business Acquisition [Line Items]	'	'	'
Maximum additional payment the Company is contingently obligated to make due to Cervitech acquisition	'	'	2,000,000
Acquisition-related liabilities	'	$600,000	'
Number of milestone	2	'	'

Financial_Instruments_and_Fair5

Financial Instruments and Fair Value Measurements Estimated Fair Value of Liabilities Measured on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Fair Value Disclosures [Abstract]	'	'
Fair value measurement at beginning of period	$1,212	$1,074
Change in fair value measurement included in operating expenses	44	15
Contingent consideration paid or settled	-608	0
Fair value measurement at end of period	$648	$1,089

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets (Details 1) (USD $)	6 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Intangible Assets Subject to Amortization:	'	'
Weighted Average Amortization Period	'10 years	'10 years
Gross Amount	$126,301	$137,696
Accumulated Amortization	-61,629	-54,350
Intangible Assets, net	64,672	83,346
Intangible Assets Not Subject to Amortization:	'	'
In-process research and development	10,640	10,640
Goodwill	154,637	154,944
Total intangible assets, net	229,949	248,930
Developed technology [Member]	'	'
Intangible Assets Subject to Amortization:	'	'
Weighted Average Amortization Period	'10 years	'10 years
Gross Amount	51,620	62,328
Accumulated Amortization	-24,925	-21,359
Intangible Assets, net	26,695	40,969
Manufacturing know-how and trade secrets [Member]	'	'
Intangible Assets Subject to Amortization:	'	'
Weighted Average Amortization Period	'12 years	'12 years
Gross Amount	21,988	21,997
Accumulated Amortization	-10,809	-9,890
Intangible Assets, net	11,179	12,107
Trade name and trademarks [Member]	'	'
Intangible Assets Subject to Amortization:	'	'
Weighted Average Amortization Period	'11 years	'11 years
Gross Amount	9,500	9,500
Accumulated Amortization	-3,810	-3,317
Intangible Assets, net	5,690	6,183
Customer relationships [Member]	'	'
Intangible Assets Subject to Amortization:	'	'
Weighted Average Amortization Period	'8 years	'8 years
Gross Amount	43,193	43,871
Accumulated Amortization	-22,085	-19,784
Intangible Assets, net	$21,108	$24,087

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets (Details 2) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'	'
Remaining 2014	$6,109	'
Future amortization expense related to intangible assets	'	'
2013	11,723	'
2014	11,248	'
2015	8,895	'
2016	7,863	'
2017	6,509	'
Thereafter through 2026	12,325	'
Intangible Assets, net	$64,672	$83,346

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets (Details Textual) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'	'
Amortization expense related to intangible assets	$3,473	$4,913	$7,470	$9,288
Goodwill and Intangible Asset Impairment	$10,708	$0	$10,708	$0

Senior_Convertible_Notes_Detai

Senior Convertible Notes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2011
Net carrying amount of the debt component	'	'	'	'	'	'
Senior Convertible Notes	$353,269,000	'	$353,269,000	'	$346,060,000	'
2.75% Senior Convertible Notes due 2017 [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Amortization of Debt Discount (Premium)	3,600,000	3,400,000	7,200,000	6,700,000	'	'
Contractual Coupon Interest Expense	2,800,000	2,800,000	5,500,000	5,500,000	'	'
Net carrying amount of the debt component	'	'	'	'	'	'
Principal amount	402,500,000	'	402,500,000	'	402,500,000	402,500,000
Unamortized debt discount	($49,231,000)	'	($49,231,000)	'	($56,440,000)	'

Senior_Convertible_Notes_Detai1

Senior Convertible Notes (Details Textual) (USD $)	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2013
Senior Convertible Notes (Textual) [Abstract]	'	'	'	'	'	'	'
Debt Instrument, convertible carrying amount	$49,300,000	'	$49,300,000	'	'	$49,300,000	'
2.75% Senior Convertible Notes due 2017 [Member]	'	'	'	'	'	'	'
Senior Convertible Notes (Textual) [Abstract]	'	'	'	'	'	'	'
Interest rate on convertible notes	'	'	'	'	2.75%	'	'
Principal amount of senior convertible notes	402,500,000	'	402,500,000	'	402,500,000	'	402,500,000
Net proceeds of unsecured senior convertible notes	'	'	'	'	359,200,000	'	'
Debt instrument, maturity date	'	'	'	'	1-Jul-17	'	'
Initial conversion rate adjustment Shares	'	'	'	'	23.7344	'	'
Base principal amount per note	'	'	'	'	1,000	'	'
Initial conversion price of convertible notes	'	'	'	'	$42.13	'	'
Business day period	'	'	'	'	'	'5 days	'
Fair value of debt conversion cost	'	'	'	'	'	88,900,000	'
Debt discount, interest rate	'	'	'	'	'	8.00%	'
Contractual Coupon Interest Expense	2,800,000	2,800,000	5,500,000	5,500,000	'	'	'
Amortization of Debt Discount (Premium)	3,600,000	3,400,000	7,200,000	6,700,000	'	'	'
Number of common stock to be purchased	'	'	'	'	'	9,553,096	'
Initial stock price at which shares to be purchased	'	'	'	'	'	$42.13	'
Cost of hedge transaction	'	'	'	'	'	80,100,000	'
Number of warrants to be acquired	'	'	'	'	'	477,654	'
Initial strike price at which Warrants to be acquired	'	'	'	'	'	988.51	'
Number of common stock shares preferred stock convertible into	'	'	'	'	'	20	'
Number Of Securities Called By Warrant Transaction	'	'	'	'	'	9,553,080	'
Cash proceeds from the sale of warrants	'	'	'	'	'	$47,900,000	'
Minimum [Member] | 2.75% Senior Convertible Notes due 2017 [Member]	'	'	'	'	'	'	'
Senior Convertible Notes (Textual) [Abstract]	'	'	'	'	'	'	'
Consecutive trading days immediately preceding calendar quarter	'	'	'	'	'	'20 days	'
Percentage of conversion price	'	'	'	'	'	130.00%	'
Maximum [Member] | 2.75% Senior Convertible Notes due 2017 [Member]	'	'	'	'	'	'	'
Senior Convertible Notes (Textual) [Abstract]	'	'	'	'	'	'	'
Consecutive trading days immediately preceding calendar quarter	'	'	'	'	'	'30 days	'
Percentage of conversion price	'	'	'	'	'	98.00%	'

StockBased_Compensation_Assump

Stock-Based Compensation Assumptions Table (Details 1) (ESPP [Member])	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
ESPP [Member]	'	'	'	'
Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP	'	'	'	'
Volatility	44.00%	57.00%	46.00%	58.00%
Expected term (years)	'1 year 2 months	'1 year 7 months	'1 year 2 months	'1 year 6 months
Risk free interest rate	0.20%	0.20%	0.20%	0.20%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

StockBased_Compensation_Detail

Stock-Based Compensation (Details Textuals 1) (USD $)

3 Months Ended

6 Months Ended

12 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

0 Months Ended

6 Months Ended

3 Months Ended

In Millions, except Share data, unless otherwise specified

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Mar. 01, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Restricted Stock Units (RSUs) [Member]

Restricted Stock Units (RSUs) [Member]

Restricted Stock Units (RSUs) [Member]

Performance-Based Restricted Stock Units [Member]

Vesting in One Year [Member]

Vesting in One Year [Member]

Vesting in Two Years [Member]

Vesting in Two Years [Member]

Maximum [Member]

Performance-Based Restricted Stock Units [Member]

Total Stockholder Return Performance-Based Restricted Stock Units [Member]

Performance-Based Restricted Stock Units [Member]

Total Stockholder Return Performance-Based Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Document Period End Date

'

30-Jun-14

'

'

'

'

'

'

'

'

'

'

Number of common stock issued to exercise stock options

74,000

478,000

177,000

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

'

'

'

'

'

'

'

'

'

'

'

'4 years 0 months

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Percentage Of Target Number Of Shares Eligible To Receive

'

'

'

'

'

'

'

'

'

'

'

250.00%

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized

$42.10

$42.10

'

'

'

'

'

'

'

'

'

'

Number of shares of common stock issued upon vesting of RSUs

'

'

'

145,000

1,355,000

665,000

'

'

'

'

'

'

Current Fiscal Year End Date

'

'--12-31

'

'

'

'

'

'

'

'

'

'

Vesting percentage

'

'

'

'

'

'

33.33%

33.33%

50.00%

33.33%

50.00%

'

StockBased_Compensation_Expens

Stock-Based Compensation Expense Table (Details 2) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated Share-based Compensation Expense	$8,785	$8,761	$16,549	$15,548
Sales Marketing and Administrative Expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated Share-based Compensation Expense	8,251	8,278	15,437	14,703
Research and development expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated Share-based Compensation Expense	483	449	947	791
Cost of goods sold [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated Share-based Compensation Expense	$51	$34	$165	$54

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Income tax expense (benefit)	$1,942,000	($76,000)	($13,153,000)	($840,000)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	'	'	37.00%	12.00%
Tax benefit related to federal research and development credit	'	$900,000	'	'
Tax benefit related to federal research and development credit, percentage	'	-13.00%	'	'

Business_Segment_Product_and_G2

Business Segment, Product, and Geographic Information (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
			segment
Segment Reporting [Abstract]	'	'	'	'
Number of Reportable Segments	'	'	1	'
Revenue from spine surgery product line offerings	'	'	'	'
Total revenues	$190,677	$165,698	$368,172	$325,202
Spine Surgery Products [Member]	'	'	'	'
Revenue from spine surgery product line offerings	'	'	'	'
Total revenues	147,333	128,682	284,640	251,348
Biologics [Member]	'	'	'	'
Revenue from spine surgery product line offerings	'	'	'	'
Total revenues	32,837	27,855	62,327	55,012
Monitoring Service [Member]	'	'	'	'
Revenue from spine surgery product line offerings	'	'	'	'
Total revenues	$10,507	$9,161	$21,205	$18,842

Business_Segment_Product_and_G3

Business Segment, Product, and Geographic Information Geographic Information (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Revenues and Net Property and Equipment by Geographical Areas [Line Items]	'	'	'	'	'
Total revenues	$190,677	$165,698	$368,172	$325,202	'
Property, Plant and Equipment, Net	134,863	'	134,863	'	128,064
UNITED STATES	'	'	'	'	'
Revenues and Net Property and Equipment by Geographical Areas [Line Items]	'	'	'	'	'
Total revenues	167,077	151,425	325,470	297,646	'
Property, Plant and Equipment, Net	110,625	'	110,625	'	109,458
International [Member]	'	'	'	'	'
Revenues and Net Property and Equipment by Geographical Areas [Line Items]	'	'	'	'	'
Total revenues	23,600	14,273	42,702	27,556	'
Property, Plant and Equipment, Net	$24,238	'	$24,238	'	$18,606

Restructuring_Charges_Details

Restructuring Charges (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Q1 2014 Restructuring Charge [Line Items]	'
Q1 2014 Net Restructuring Charge	$6.40
Q1 2014 Gain on Restructuring Writeoffs	0.1
Q1 2014 Restructuring Liability	$6

Contingencies_Details

Contingencies (Details) (USD $)

3 Months Ended

6 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Sep. 30, 2012

Dec. 31, 2013

Dec. 31, 2011

Mar. 31, 2013

Dec. 31, 2010

Jun. 30, 2014

Dec. 31, 2011

Dec. 10, 2012

Medtronic Litigation [Member]

Medtronic Litigation [Member]

Medtronic Litigation [Member]

Medtronic Litigation [Member]

Medtronic Litigation [Member]

Medtronic Litigation [Member]

Trademark Infringement [Member]

Trademark Infringement [Member]

Trademark Infringement [Member]

Trademark Infringement [Member]

patent

Legal Proceedings (Textual) [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of patents assigned or licensed

'

'

'

'

12

'

'

'

'

'

'

'

'

'

Number of patents withdrawn

'

'

'

'

3

'

'

'

'

'

'

'

'

'

Number of patents remaining

'

'

'

'

9

'

'

'

'

'

'

'

'

'

Company's Patents in Initial Phase of Litigation

'

'

'

'

1

'

'

'

'

'

'

'

'

'

Number of Patents Selected for Litigation

'

'

'

'

3

'

'

'

'

'

'

'

'

'

Other Company's Patents in Initial Phase of Litigation

'

'

'

'

3

'

'

'

'

'

'

'

'

'

Litigation award

$0

$0

$30,000,000

$0

'

'

$101,200,000

'

$101,200,000

'

'

'

'

'

RoyaltyAccrualCharge

'

'

'

'

'

'

'

7,900,000

'

'

'

'

'

'

TransferOfFundsNotAvailableForWithdrawalOrUse

'

'

'

'

25,000,000

'

'

'

'

'

'

'

'

'

Company's cash and investment in escrow

'

'

'

'

'

'

'

113,300,000

'

'

'

'

62,500,000

'

Approximate loss contingency

'

'

'

'

'

'

'

'

'

13,000,000

'

'

'

'

Unrecorded royalty damages

'

'

'

'

700,000

'

'

'

'

'

'

'

'

'

Loss Contingency, Settlement Agreement, Consideration

'

'

'

'

'

7,500,000

'

'

'

'

'

'

'

'

Jury award

'

'

'

'

'

'

'

'

'

'

60,000,000

30,000,000

'

'

Release of funds from escrow

'

'

'

'

'

'

'

'

'

'

'

'

'

$62,500,000