Nuvasive (NUVA) 10-K 20 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 18, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	NUVASIVE INC
Entity Central Index Key	1,142,596
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	NUVA
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2.7
Entity Common Stock, Shares Outstanding		51,635,602

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 117,840	$ 72,803
Restricted cash and investments		3,901
Accounts receivable, net of allowances of $16,171 and $13,026, respectively	196,487	200,220
Inventory, net	273,244	247,138
Prepaid income taxes	16,905	17,209
Prepaid expenses and other current assets	13,733	18,792
Total current assets	618,209	560,063
Property and equipment, net	238,841	215,326
Intangible assets, net	252,048	280,774
Goodwill	561,366	536,926
Deferred tax assets	5,263	6,440
Restricted cash and investments	2,395	1,494
Other assets	29,737	39,117
Total assets	1,707,859	1,640,140
Current liabilities:
Accounts payable and accrued liabilities	105,877	75,767
Contingent consideration liabilities	7,560	18,952
Accrued payroll and related expenses	59,960	55,618
Litigation liabilities	1,415	8,150
Income tax liabilities	4,648	2,908
Total current liabilities	179,460	161,395
Long-term senior convertible notes	602,526	582,920
Deferred and income tax liabilities, non-current	4,964	18,870
Other long-term liabilities	86,384	77,539
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized, none outstanding
Common stock, $0.001 par value; 120,000,000 shares authorized at December 31, 2018 and December 31, 2017, 56,648,077 and 56,164,060 issued and outstanding at December 31, 2018 and December 31, 2017, respectively	61	60
Additional paid-in capital	1,397,829	1,363,549
Accumulated other comprehensive loss	(8,628)	(6,933)
Retained earnings	17,241	4,762
Treasury stock at cost; 5,116,496 shares and 5,001,886 shares at December 31, 2018 and December 31, 2017, respectively	(571,978)	(565,867)
Total NuVasive, Inc. stockholders’ equity	834,525	795,571
Non-controlling interests		3,845
Total equity	834,525	799,416
Total liabilities and equity	$ 1,707,859	$ 1,640,140

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, allowances	$ 16,171	$ 13,026
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	56,648,077	56,164,060
Common stock, shares outstanding	56,648,077	56,164,060
Treasury stock at cost, shares	5,116,496	5,001,886

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Total revenue	$ 1,101,714	$ 1,026,685	$ 962,132
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue	311,159	268,441	240,105
Gross profit	790,555	758,244	722,027
Operating expenses:
Sales, marketing and administrative	575,836	539,507	533,600
Research and development	61,695	50,425	47,999
Amortization of intangible assets	50,670	48,039	42,001
Purchase of in-process research and development	8,913
Litigation liability loss (gain)	27,800	4,500	(43,310)
Business transition costs	11,473	4,287	18,138
Total operating expenses	736,387	646,758	598,428
Interest and other expense, net:
Interest income	586	440	1,091
Interest expense	(37,857)	(38,021)	(40,520)
Loss on repurchases of convertible notes			(19,085)
Other income (expense), net	(8,174)	(1,542)	(305)
Total interest and other expense, net	(45,445)	(39,123)	(58,819)
Income before income taxes	8,723	72,363	64,780
Income tax benefit (expense)	3,756	7,492	(29,309)
Consolidated net income	12,479	79,855	35,471
Add back net loss attributable to non-controlling interests		(1,743)	(1,721)
Net income attributable to NuVasive, Inc.	$ 12,479	$ 81,598	$ 37,192
Net income per share attributable to NuVasive, Inc.:
Basic	$ 0.24	$ 1.60	$ 0.74
Diluted	$ 0.24	$ 1.48	$ 0.69
Weighted average shares outstanding:
Basic	51,382	50,874	50,077
Diluted	52,355	55,193	54,102
Product [Member]
Revenue
Total revenue	$ 986,458	$ 938,981	$ 893,544
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue	234,509	207,307	195,605
Service [Member]
Revenue
Total revenue	115,256	87,704	68,588
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue	$ 76,650	$ 61,134	$ 44,500

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income	$ 12,479	$ 79,855	$ 35,471
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable securities, net of tax		(1)	330
Translation adjustments, net of tax	(1,695)	3,699	1,151
Other comprehensive (loss) income:	(1,695)	3,698	1,481
Total consolidated comprehensive income	10,784	83,553	36,952
Net loss attributable to non-controlling interests		1,743	1,721
Comprehensive income attributable to NuVasive, Inc.	$ 10,784	$ 85,296	$ 38,673

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings (Accumulated Deficit) [Member]	Treasury Stock [Member]	Total Nuvasive, Inc. Stockholders? Equity [Member]	Non-controlling Interest [Member]
Adjustment for full retrospective adoption of accounting standard	$ 1,625				$ 1,625		$ 1,625
Beginning Balance at Dec. 31, 2015	718,843	$ 53	$ 989,387	$ (12,112)	(104,006)	$ (161,788)	711,534	$ 7,309
Beginning Balance, Shares at Dec. 31, 2015		52,616				(3,316)
Issuance of common stock under employee and director stock option and purchase plans	(15,357)	$ 2	60,720			$ (76,079)	(15,357)
Issuance of common stock under employee and director stock option and purchase plans, Shares		2,480				(1,443)
Stock-based compensation expense	24,981		24,981				24,981
Tax benefits related to convertible note repurchase	13,374		13,374				13,374
Issuance of common stock in connection with royalty milestone achievement	5,761		5,761				5,761
Issuance of common stock in connection with royalty milestone achievement, Shares		88
Issuance of common stock through conversion of notes payable, Shares		1
Sale of warrants	44,850		44,850				44,850
Convertible note hedge	(111,150)		(111,150)				(111,150)
Equity component of convertible note issuance	84,784		84,784				84,784
Equity component of convertible note repurchase	(100,524)		(100,524)				(100,524)
Debt issuance costs attributable to convertible feature	(1,931)		(1,931)				(1,931)
Securities registration fees	(14)		(14)				(14)
Net income attributable to NuVasive, Inc.	37,192				37,192		37,192
Net loss attributable to non-controlling interests	(1,721)							(1,721)
Other comprehensive income	1,481			1,481			1,481
Ending Balance at Dec. 31, 2016	702,194	$ 55	1,010,238	(10,631)	(65,189)	$ (237,867)	696,606	5,588
Ending Balance, Shares at Dec. 31, 2016		55,185				(4,759)
Adjustment for modified retrospective adoption of accounting standard	(11,647)				(11,647)		(11,647)
Issuance of common stock under employee and director stock option and purchase plans	(1,877)	$ 1	15,569			$ (17,447)	(1,877)
Issuance of common stock under employee and director stock option and purchase plans, Shares		743				(243)
Stock-based compensation expense	22,062		22,062				22,062
Issuance of common stock in connection with royalty milestone achievement	5,131		5,131				5,131
Issuance of common stock in connection with royalty milestone achievement, Shares		90
Settlement of warrants		$ 3	(3)
Settlement of warrants, Shares		3,657
Settlement of convertible note hedge			310,553			$ (310,553)
Settlement of convertible note hedge, Shares		(4,161)
Equity component of convertible note settlement		$ 1	(1)
Equity component of convertible note settlement, Shares		650
Net income attributable to NuVasive, Inc.	81,598				81,598		81,598
Net loss attributable to non-controlling interests	(1,743)							(1,743)
Other comprehensive income	3,698			3,698			3,698
Ending Balance at Dec. 31, 2017	799,416	$ 60	1,363,549	(6,933)	4,762	$ (565,867)	795,571	3,845
Ending Balance, Shares at Dec. 31, 2017		56,164				(5,002)
Issuance of common stock under employee and director stock option and purchase plans	5,199	$ 1	11,309			$ (6,111)	5,199
Issuance of common stock under employee and director stock option and purchase plans, Shares		466				(114)
Stock-based compensation expense	27,353		27,353				27,353
Issuance of common stock in connection with royalty milestone achievement	4,719		4,719				4,719
Issuance of common stock in connection with royalty milestone achievement, Shares		18
Net income attributable to NuVasive, Inc.	12,479				12,479		12,479
Consideration paid in excess of non-controlling interests	(9,101)		(9,101)				(9,101)
Net loss attributable to non-controlling interests	(3,845)							$ (3,845)
Other comprehensive income	(1,695)			(1,695)			(1,695)
Ending Balance at Dec. 31, 2018	$ 834,525	$ 61	$ 1,397,829	$ (8,628)	$ 17,241	$ (571,978)	$ 834,525
Ending Balance, Shares at Dec. 31, 2018		56,648				(5,116)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Consolidated net income	$ 12,479	$ 79,855	$ 35,471
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	129,765	121,176	102,713
Purchase of in-process research and development	8,913
Deferred income taxes	(11,396)	(12,838)	26,292
Loss on repurchases of convertible notes			19,085
Amortization of non-cash interest	20,123	20,538	22,721
Stock-based compensation	25,673	22,391	26,924
Net loss on strategic investments	4,421
Reserves on current assets	14,834	5,622	11,452
Other non-cash adjustments	23,703	16,561	16,928
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	4,562	(26,610)	(33,421)
Inventory	(38,646)	(35,867)	(22,624)
Prepaid expenses and other current assets	(1,280)	(12,681)	(3,875)
Accounts payable and accrued liabilities	20,518	(5,558)	12,376
Contingent consideration liabilities	(300)	(11,200)
Accrued payroll and related expenses	2,595	3,975	8,841
Litigation liability	1,165	8,150	(88,450)
Income taxes	2,054	3,455	23,652
Net cash provided by operating activities	219,183	176,969	158,085
Investing activities:
Acquisition of Ellipse Technologies, net of cash acquired			(380,080)
Other acquisitions and investments	(55,266)	(62,370)	(108,591)
Proceeds from other investments	3,584
Purchases of intangible assets	(7,682)	(2,270)	(5,918)
Purchases of property and equipment	(101,921)	(110,221)	(88,372)
Purchases of marketable securities			(128,956)
Proceeds from sales of marketable securities			407,032
Net cash used in investing activities	(161,285)	(174,861)	(304,885)
Financing activities:
Proceeds from the issuance of common stock	8,127	9,991	9,492
Payment of contingent consideration	(19,450)	(19,400)	(422)
Purchase of treasury stock	(2,928)	(11,860)	(24,734)
Proceeds from issuance of convertible debt, net of issuance costs			634,140
Proceeds from sale of warrants			44,850
Purchase of convertible note hedge			(111,150)
Repurchases of convertible notes		(63,317)	(439,519)
Proceeds from revolving line of credit	100,000	60,000	50,000
Repayments on revolving line of credit	(100,000)	(60,000)	(50,000)
Other financing activities	(327)	(2,442)	(1,834)
Net cash (used in) provided by financing activities	(14,578)	(87,028)	110,823
Effect of exchange rate changes on cash	(1,283)	2,070	(929)
Increase (decrease) in cash, cash equivalents and restricted cash	42,037	(82,850)	(36,906)
Cash, cash equivalents and restricted cash at beginning of period	78,198	161,048	197,954
Cash, cash equivalents and restricted cash at end of period	120,235	78,198	161,048
Supplemental disclosure of non-cash transactions:
Issuance of common stock in connection with royalty milestone achievement	4,719	5,131	5,761
Supplemental cash flow information:
Interest paid	17,182	15,897	13,249
Income taxes paid (refunded)	$ 5,510	$ 1,459	$ (20,499)

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Cash Flows [Abstract]
Cash and cash equivalents	$ 117,840	$ 72,803	$ 153,643
Restricted cash, current		3,901
Restricted cash, non-current	2,395	1,494	7,405
Total cash, cash equivalents and restricted cash reported in the Consolidated Statements of Cash Flows	$ 120,235	$ 78,198	$ 161,048

Organization and Significant Ac

Organization and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Significant Accounting Policies	1. Organization and Significant Accounting Policies 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’s principal product offering includes a minimally disruptive surgical platform called Maximum Access Surgery, or MAS. 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 safe and reproducible outcomes for the surgeon and the patient. The platform includes the Company’s proprietary software-driven nerve detection and avoidance systems and Intraoperative Monitoring (“IOM”) services and support; MaXcess, an integrated split-blade retractor system; and a wide variety of specialized implants and biologics. To assist with surgical procedures, the Company offers a technology platform called Integrated Global Alignment (“iGA”); in which products and computer assisted technology under the MAS platform help achieve more precise spinal alignment. The individual components of the MAS platform, and many of the Company’s products, can also be used in open or traditional spine surgery. The Company continues to focus 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 procedurally integrated solutions use innovative, technological advancements and the MAS platform to provide surgical efficiency, operative reliability, and procedural versatility. The Company offers a range of implants for spinal surgery, which include its porous titanium and polyetheretherketone (“PEEK”) implants under its Advanced Materials Science portfolio, fixation devices such as customizable rods, plates and screws, bone allograft in patented saline packaging, allogeneic and synthetic biologics, and disposables used in IOM. The Company makes available MAS instrument sets, MaXcess and neuromonitoring systems to hospitals to facilitate surgeon access to the spine to perform restorative and fusion procedures using the Company’s implants and fixation devices. The Company sells MAS instrument sets, MaXcess and neuromonitoring systems to hospitals, however, such sales are immaterial to the Company’s results of operations. The Company also designs and sells expandable growing rod implant systems that can be non-invasively lengthened following implantation with precise, incremental adjustments via an external remote controller using magnetic technology called MAGnetic External Control, or MAGEC, which allows for the minimally invasive treatment of early-onset and adolescent scoliosis. This technology is also the basis for the Company’s PRECICE limb lengthening system, which allows for the correction of long bone limb length discrepancy, as well as enhanced bone healing in patients that have experienced traumatic injury. The Company continues to develop a wide variety of projects which broaden its MAS and other product platforms and advance the applications of its unique technology into procedurally integrated surgical solutions that improve clinical and economic outcomes, including Pulse, a surgical automation platform which incorporates neuromonitoring, surgical planning, rod bending, imaging, navigation, and other automation. Pulse is a combined hardware and software platform designed to achieve surgical efficiencies via real-time feedback to aid in clinical decision making and to optimize the procedural workflow in the operating room. The Company continues to pursue business and technology acquisition targets and strategic relationships. Basis of Presentation and Principles of Consolidation The accompanying 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 non-controlling interest at the acquisition date and classifies the amounts attributable to non-controlling interest separately in equity in the Company's 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 Company has reclassified historically presented revenue and cost of revenue to conform to the current year presentation, which now reflects revenue and costs allocated to the Company’s product and service offerings. These reclassifications had no impact on previously reported results of operations. Additionally, as required by Accounting Standards Update 2014-09 Revenue from Contracts with Customers Revenue from Contracts with Customers Use of Estimates To prepare financial statements in conformity with generally accepted accounting principles (“GAAP”) accepted in the United States, management must make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Recent Accounting Pronouncements Not Yet Adopted In Leases, Leases Leases In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments – Credit Losses In January 2017, the FASB issued Accounting Standards Update No. 2017-04, Intangibles – Goodwill and Other In July 2017, the FASB issued Accounting Standards Update No. 2017-11, Earnings Per Share, Distinguishing Liabilities from Equity, Derivatives and Hedging Derivatives and Hedging In August 2018, the FASB issued Accounting Standards Update No. 2018-13, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement In September 2018, the FASB issued Accounting Standards Update No. 2018-15, Intangible – Goodwill and Other – Internal-Use Software Recently Adopted Accounting Standards In May 2014, the FASB issued ASU 2014-09, an updated standard on revenue recognition. The standard effectively replaces Accounting Standards Codification 605 Revenue Recognition (“ASC 605”) with ASC 606. In summary, the changes to the guidance in revenue recognition under ASC 606 focuses on the existence of a contract with the customer (whether written, oral, or implied by an entity’s customary business practices), the concept that the performance obligation is fulfilled when the customer obtains control of the asset/service, versus the transfer of risk and reward, and the requirement that variable consideration (including rebates, discounts, etc.) and incremental costs must be estimated and recognized in the amount that is expected or most likely to be realized over the term of the contract fulfillment. Prior to the adoption of ASC 606, the Company recognized revenue in accordance with ASC 605 when all four of the following criteria were met: (i) persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured. Specifically, revenue from the sale of implants, biologics and disposables was generally recognized upon a purchase order from the hospital or acknowledgment from the hospital indicating product use or implantation or upon shipment to third-party customers who immediately accepted title. Revenue from the sale of instrument sets was recognized upon receipt of a purchase order and the subsequent shipment to customers who immediately accepted title. Revenue from neuromonitoring services was recognized in the period the service was performed for the amount of payment expected to be received. The Company adopted ASC 606 as of January 1, 2018, electing full retrospective method of adoption, which resulted in a change in its accounting policy for revenue recognition and related adjustments to the Consolidated Financial Statements for all periods presented. The Company applied the practical expedients permitted under ASC 606 for which (i) contracts with customers originating prior to January 1, 2016 do not require disclosure for the amount of consideration allocated to remaining performance obligations or an explanation of when the Company expects to recognize that amount as revenue; (ii) contracts beginning and completing in the same annual reporting period need not be restated; and (iii) hindsight for estimating variable consideration for completed contracts is permitted. The Company recognizes revenue from spinal surgery hardware and ancillary products at a point in time in two types of transactions: (i) procedural based transactions with products used during surgery defined as “charge sheet orders”, and (ii) shipping transactions which represent the stocking of product or the purchase of instrumentation to support future surgeries defined as “stocking and capital orders.” The Company also recognizes revenue at a point in time associated with surgical-related servicing procedures, including neuromonitoring services which are defined as “surgical-related services.” Other sources of revenue, such as leasing revenue and royalties, are immaterial to the Consolidated Financial Statements. For charge sheet orders, the sale occurs when the surgery is performed and a charge sheet is submitted to the Company by its sales representative identifying the products consumed during the surgery. The charge sheet, as signed by the hospital, serves as a confirmation and acknowledgement of the Company’s products consumed during a surgery. Under ASC 605, persuasive evidence of an arrangement and delivery of product was deemed to have occurred once the charge sheet was processed, and an associated authorization or acknowledgement from the customer was received. Under ASC 606, the Company’s charge sheet orders are considered to be a contract with a customer when a surgery is scheduled with the Company as requested by the hospital or surgeon, and the products are consumed during the surgery or implanted into the patient. Revenue recognition under ASC 606 occurs upon completion of the Company’s performance obligation, which occurs upon consumption of the products during surgery and receipt of the charge sheet. In the event that information related to the surgical event and consumption of product is not readily available the Company recognizes revenue upon a purchase order from the hospital or acknowledgment from the hospital indicating product use. For stocking and capital orders, under ASC 605, delivery was deemed to have occurred when the title, including all risks and rewards of ownership of the products specified in the sales agreement had passed to the buyer. Accordingly, title, including all risks and rewards of ownership, passed based on the shipping terms. Under ASC 606, the Company’s stocking and capital order performance obligation is considered to be satisfied when the buyer assumes control of the asset, either upon shipment or delivery depending on the terms, and ability to direct the use of the asset as appropriate without the Company’s consent. Under both ASC 605 and ASC 606, revenue from surgical-related services, such as neuromonitoring services, is recognized in the period the service is performed based on the delivery of a services report to the customer. The Company recognizes revenue for the amount of payment expected to be received. The Company bills either hospitals or insurance companies for different aspects of the service, as applicable. Revenue from hospitals is recognized based on agreed upon pricing. Revenue from insurance companies is recognized using the expected value method, as the Company bills at a gross rate which is generally not the rate ultimately collected. Under ASC 605, the Company has historically estimated the amounts of returns, trade-ins, discounts, rebates, credits or incentives as offsets to the total transaction price or revenue associated with the sale. In limited situations, when historical information was not available or reliable, the Company would defer revenue recognition until completion of all performance obligations. Under ASC 606, the Company analyzes sales that could include variable consideration, and estimates the expected or most likely amount of revenue after returns, trade-ins, discounts, rebates, credits, and incentives. In making these estimates, the Company considers whether the amount of variable consideration is constrained and is included in revenue only to the extent that it is probable that a significant reversal of the revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The Company earns sales-based royalty revenue over time from sales of products using existing biologics intellectual property (“IP”) that is out-licensed to certain companies. Under ASC 605, royalty revenue was recognized as earned and when collection was reasonably assured and was generally estimated and recorded in the same period as the sales that generated the royalty obligation. ASC 606 provides an exception for sales or usage-based royalties from the guidance for accounting for variable consideration, allowing the royalty revenue from the license of IP to be recognized when the performance obligation has been satisfied and the subsequent sale has occurred. Therefore, the Company estimates monthly royalty revenue as its performance obligation is satisfied. The Company does not expect a significant impact to royalty revenue under the adoption of ASC 606 as it has historically estimated and accrued royalty revenue in the period earned. The Company historically expensed incremental costs, such as commissions associated with sales contracts, as incurred. Under ASU 2014-09, ASC 340-40, Other Assets and Deferred Costs – Contracts with Customers As a result of the full retrospective method of adoption of ASC 606, the Company recorded a $1.6 million adjustment to January 1, 2016 accumulated deficit. The cumulative effect of the change on retained earnings as of December 31, 2017 for the full retrospective method of adoption of ASC 606 was $0.3 million. The following tables summarize in a condensed presentation the impact of the adoption of ASC 606 on the Company’s previously reported Consolidated Balance Sheet as of December 31, 2017, the Consolidated Statements of Operations and Comprehensive Income for the years ended December 31, 2017 and 2016, and the Consolidated Statements of Cash Flows for the years ended December 31, 2017 and 2016. NUVASIVE, INC. CONSOLIDATED BALANCE SHEET (in thousands) As of December 31, 2017 As reported Adjustments As Adjusted Accounts receivable, gross $ 212,709 $ 537 [a] $ 213,246 Allowances on accounts receivable (13,669 ) 643 [b] (13,026 ) Inventory, net 247,245 (107 ) [c] 247,138 Other current assets 112,705 — 112,705 Total current assets 558,990 1,073 560,063 Remaining other assets 1,080,077 — 1,080,077 Total assets $ 1,639,067 $ 1,073 $ 1,640,140 Accounts payable and accrued liabilities 75,076 691 [d] 75,767 Accrued payroll and related expenses 55,582 36 [e] 55,618 Other current liabilities 30,010 — 30,010 Total current liabilities 160,668 727 161,395 Deferred and income tax liabilities, non-current 18,786 84 [f] 18,870 Other long-term liabilities 660,459 — 660,459 Total NuVasive, Inc. stockholders’ equity 795,309 262 [g] 795,571 Non-controlling interests 3,845 — 3,845 Total equity 799,154 262 799,416 Total liabilities and equity $ 1,639,067 $ 1,073 $ 1,640,140 [a] Represents cumulative impact from January 1, 2016 to the period presented on accounts receivable for the full retrospective method of adoption of ASC 606. [b] Represents cumulative impact from January 1, 2016 to the period presented on allowances on accounts receivable for the full retrospective method of adoption of ASC 606. [c] Represents cumulative impact from January 1, 2016 to the period presented on inventory for the full retrospective method of adoption of ASC 606. [d] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable and accrued returns for the full retrospective method of adoption of ASC 606. [e] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable for the full retrospective method of adoption of ASC 606. [f] Represents cumulative impact from January 1, 2016 to the period presented on deferred tax liabilities for the full retrospective method of adoption of ASC 606. [g] Represents cumulative impact from January 1, 2016 to the period presented on retained earnings for the full retrospective method of adoption of ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands, except per share amounts) Year ended December 31, 2017 As reported Adjustments As adjusted Revenue Product revenue $ 941,816 $ (2,835 ) [a] $ 938,981 Service revenue 87,704 — 87,704 Total revenue 1,029,520 (2,835 ) 1,026,685 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 207,874 (567 ) [b] 207,307 Cost of services 61,134 — 61,134 Total cost of revenue 269,008 (567 ) 268,441 Gross profit 760,512 (2,268 ) 758,244 Operating expenses: Sales, marketing and administrative 539,913 (406 ) [c] 539,507 Other operating expenses 107,251 — 107,251 Total operating expenses 647,164 (406 ) 646,758 Total interest and other expense, net (39,123 ) — (39,123 ) Income tax benefit 7,038 454 [d] 7,492 Consolidated net income $ 81,263 $ (1,408 ) [e] $ 79,855 Add back net loss attributable to non-controlling interests $ (1,743 ) $ — $ (1,743 ) Net income attributable to NuVasive, Inc. $ 83,006 $ (1,408 ) [e] $ 81,598 Net income per share attributable to NuVasive, Inc.: Basic $ 1.63 $ (0.03 ) [f] $ 1.60 Diluted $ 1.50 $ (0.02 ) [f] $ 1.48 Comprehensive income attributable to NuVasive, Inc. $ 86,704 $ (1,408 ) [e] $ 85,296 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Revenue Product revenue $ 893,484 $ 60 [a] $ 893,544 Service revenue 68,588 — 68,588 Total revenue 962,072 60 962,132 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 195,593 12 [b] 195,605 Cost of services 44,500 — 44,500 Total cost of revenue 240,093 12 240,105 Gross profit 721,979 48 722,027 Operating expenses: Sales, marketing and administrative 533,624 (24 ) [c] 533,600 Other operating expenses 64,828 — 64,828 Total operating expenses 598,452 (24 ) 598,428 Total interest and other expense, net (58,819 ) — (58,819 ) Income tax expense (29,282 ) (27 ) [d] (29,309 ) Consolidated net income $ 35,426 $ 45 [e] $ 35,471 Add back net loss attributable to non-controlling interests $ (1,721 ) $ — $ (1,721 ) Net income attributable to NuVasive, Inc. $ 37,147 $ 45 [e] $ 37,192 Net income per share attributable to NuVasive, Inc.: Basic $ 0.74 $ 0.00 [f] $ 0.74 Diluted $ 0.69 $ 0.00 [f] $ 0.69 Comprehensive income attributable to NuVasive, Inc. $ 38,628 $ 45 [e] $ 38,673 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2017 As reported Adjustments As adjusted Consolidated net income $ 81,263 $ (1,408 ) [a] $ 79,855 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 5,718 (96 ) [b] 5,622 Deferred income tax benefit (12,384 ) (454 ) [c] (12,838 ) Other adjustments to reconcile net income 180,666 — 180,666 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (29,389 ) 2,779 [d] (26,610 ) Inventory (35,300 ) (567 ) [e] (35,867 ) Prepaid expenses and other current assets (12,681 ) [f] — (12,681 ) Accounts payable and accrued liabilities (16,617 ) (141 ) [g] (16,758 ) Litigation liability 8,150 — 8,150 Accrued payroll and related expenses 4,088 (113 ) [g] 3,975 Income taxes 3,455 — 3,455 Net cash provided by operating activities 176,969 — 176,969 Net cash used in investing activities (174,861 ) — (174,861 ) Net cash used in financing activities (87,028 ) — (87,028 ) Effect of exchange rate changes on cash 2,070 — 2,070 Decrease in cash, cash equivalents and restricted cash $ (82,850 ) $ — $ (82,850 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Consolidated net income $ 35,426 $ 45 [a] $ 35,471 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 11,408 44 [b] 11,452 Deferred income tax expense 26,265 27 [c] 26,292 Other adjustments to reconcile net income 188,371 — 188,371 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (33,250 ) (171 ) [d] (33,421 ) Inventory (22,636 ) 12 [e] (22,624 ) Prepaid expenses and other current assets (3,875 ) [f] — (3,875 ) Accounts payable and accrued liabilities 12,325 51 [g] 12,376 Litigation liability (88,450 ) — (88,450 ) Accrued payroll and related expenses 8,849 (8 ) [g] 8,841 Income taxes 23,652 — 23,652 Net cash provided by operating activities 158,085 — 158,085 Net cash used in investing activities (304,885 ) — (304,885 ) Net cash provided by financing activities 110,823 — 110,823 Effect of exchange rate changes on cash (929 ) — (929 ) Decrease in cash, cash equivalents and restricted cash $ (36,906 ) $ — $ (36,906 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Classification of Certain Cash Receipts and Cash Payments In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Restricted Cash In January 2017, the FASB issued Accounting Standards Update No. 2017-01, Clarifying the Definition of a Business In February 2017, the FASB issued Accounting Standards Update No. 2017-05, Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets In May 2017, the FASB issued Accounting Standards Update No. 2017-09, Compensation – Stock Compensation In March 2018, the FASB issued Accounting Standards Update No. 2018-05, Income taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 In June 2018, the FASB issued Accounting Standards Update No. 2018-07, Compensation – Stock Compensation Revenue Recognition In accordance with ASC 606 guidance, the Company recognizes revenue upon the transfer of goods or services to a customer at an amount that reflects the expected consideration to be received in exchange for those goods or services. The principles in ASC 606 are applied using the following five steps: (i) identify the contract with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) the Company satisfies its performance obligation(s). Specifically, revenue from the sale of implants and disposables is generally recognized at an amount that reflects the expected consideration upon notice that the Company’s products have been used in a surgical procedure or upon shipment to a third-party customer assuming control of the products. Revenue from neuromonitoring services is recognized in the period the service is performed for the amount of consideration expected to be received. Accounts Receivable and Related Valuation Accounts Accounts receivable in the accompanying Consolidated Balance Sheets are presented net of allowances for doubtful accounts. In addition, the Company establishes a liability for estimated sales returns and a reserve for price adjustments that are recorded as a reduction to revenue. The liability and reserve are maintained to account for the future product returns and price adjustments of products sold in the current period. Concentration of Credit Risk and Significant Customers Financial instruments, which potentially subject the Company to concentrations of credit risk, consist primarily of cash and cash equivalents, marketable securities and accounts receivable. The Company limits its exposure to credit loss by placing its cash and investments with high credit quality financial institutions. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. The Company has a diverse customer base and no single customer represented greater than ten percent of sales or accounts receivable for any of the periods presented. Fair Value of Financial Instruments The Company’s financial instruments consist principally of cash and cash equivalents, marketable securities, restricted investments, derivatives, contingent consideration liabilities, accounts receivable, accounts payable, accrued expenses, and Senior Convertible Notes. The Company measures certain assets and liabilities in accordance with authoritative guidance which requires fair value measurements to 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 the levels of the fair value measurement hierarchy during the years presented. Cash and Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash and have an original maturity of three months or less at the time of purchase to be cash equivalents. Inventory Net inventory as of December 31, 2018 consisted of $259.4 million of finished goods, $5.0 million of work in progress and $8.8 million of raw materials. Net inventory as of December 31, 2017 consisted of $232.3 million of finished goods, $9.8 million of work in progress and $5.0 million of raw materials. Finished goods include specialized implants and disposables and are stated at the lower of cost or market determined by utilizing a standard cost method, which includes assessment of capitalized variances, which approximates the weighted average cost. Work in progress and raw materials represent the underlying material, and labor for work in progress, that ultimately yield finished goods upon completion and are subject to lower of cost or market. The Company reviews the components of its inventory on a periodic basis for excess and obsolescence and adjusts inventory to its net realizable value as necessary. Excess and Obsolete Inventory The Company provides an inventory reserve for estimated obsolescence and excess inventory based upon historical turnover and assumptions about future demand for its products and market conditions. The Company’s allograft products have shelf lives ranging from two to five years and are subject to demand fluctuations based on the availability and demand for alternative products. The Company’s inventory, which consists primarily of disposables and specialized implants, is at risk of obsolescence following the introduction and development of new or enhanced products. The Company’s estimates and assumptions for excess and obsolete inventory are reviewed and updated on a quarterly basis. The estimates the Company uses for demand are also used for near-term capacity planning and inventory purchasing and are consistent with its revenue forecasts. Increases in the reserve for excess and obsolete inventory result in a corresponding charge to cost of products sold. Historically, the Company’s reserves have been adequate to cover losses. Goodwill and Intangible Assets The Company’s goodwill represents the excess of the cost over the fair value of net assets acquired from its business combinations. The determination of the value of goodwill and intangible assets arising from business combinations and asset acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including capitalized Intangible assets acquired in a business combination that are used for in-process research and development activities are considered indefinite lived until the completion or abandonment of the associated research and development efforts. Upon reaching the end of the relevant research and development project, the Company will amortize the acquired

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2018
Balance Sheet Details [Abstract]
Balance Sheet Details	2. Balance Sheet Details Property and Equipment, net Property and equipment, net, consisted of the following: December 31, ( in thousands, except years Useful Life 2018 2017 Instrument sets 4 $ 326,831 $ 287,435 Machinery and equipment 5 to 7 58,585 49,142 Computer equipment and software 3 to 7 127,539 102,729 Leasehold improvements 2 to 15 32,973 23,532 Furniture and fixtures 3 to 7 8,961 8,311 Building and improvements 10 to 20 20,216 20,146 Land — 1,277 1,277 576,382 492,572 Less: accumulated depreciation and amortization (337,541 ) (277,246 ) $ 238,841 $ 215,326 Property and equipment mainly consisted of instrument sets, which surgeons and hospitals that purchase implants, biologics and disposables for use in individual surgical procedures. Depreciation expense was $75.4 million, $69.5 million, and $57.1 million for the years ended December 31, 2018, 2017 and 2016, respectively. At December 31, 2018 and 2017, gross assets recorded under capital leases of $1.5 million and $1.8 million, respectively, are included in machinery and equipment. Depreciation of the assets under capital leases is included in depreciation expense. The Company depreciates leasehold improvements over their estimated useful lives or the term of the applicable lease, whichever is shorter. Capitalized internal-use software costs include only those direct costs associated with the actual development or acquisition of computer software for internal use, including costs associated with the design, coding, installation, and testing of the system. At December 31, 2018 and 2017, the Company had $40.6 million and $29.9 million in unamortized capitalized internal-use software costs, respectively. Amortization expense related to capitalized internal-use software costs was $10.6 million, $10.1 million and $7.4 million for the years ended December 31, 2018, 2017 and 2016, respectively. Goodwill and Intangible Assets Goodwill and intangible assets as of December 31, 2018 consisted of the following: Weighted- Average Amortization Period Gross Accumulated Intangible ( in thousands, except years (in years) Amount Amortization Assets, net Intangible assets subject to amortization: Developed technology 8 $ 271,748 $ (131,730 ) $ 140,018 Manufacturing know-how and trade secrets 13 30,814 (17,926 ) 12,888 Trade name and trademarks 9 25,500 (13,901 ) 11,599 Customer relationships 9 147,021 (59,478 ) 87,543 Total intangible assets subject to amortization 9 $ 475,083 $ (223,035 ) $ 252,048 Intangible assets not subject to amortization: Goodwill 561,366 Total goodwill and intangible assets, net $ 813,414 Goodwill and intangible assets as of December 31, 2017 consisted of the following: Weighted- Average Amortization Period Gross Accumulated Intangible ( in thousands, except years (in years) Amount Amortization Assets, net Intangible assets subject to amortization: Developed technology 8 $ 271,748 $ (98,693 ) $ 173,055 Manufacturing know-how and trade secrets 13 30,653 (15,542 ) 15,111 Trade name and trademarks 9 25,200 (10,559 ) 14,641 Customer relationships 9 122,249 (44,282 ) 77,967 Total intangible assets subject to amortization 9 $ 449,850 $ (169,076 ) $ 280,774 Intangible assets not subject to amortization: Goodwill 536,926 Total goodwill and intangible assets, net $ 817,700 Total expense related to the amortization of intangible assets which is recorded in either cost of goods sold or operating expenses in the Consolidated Statements of Operations depending on the functional nature of the intangible, was $54.4 million, $51.7 million and $45.6 million for the years ended December 31, 2018, 2017 and 2016, respectively. During the year ended December 31, 2018, in connection with acquisitions, including changes in purchase price allocations, and other investments, the Company recorded additions to definite-lived intangible assets and goodwill of $26.2 million and $25.9 million, respectively. Goodwill recorded in business combinations is primarily attributable to synergies expected to arise after the acquisition. included in this Annual Report The changes to goodwill are comprised of the following: ( in thousands December 31, 2017 Gross goodwill $ 545,226 Accumulated impairment loss (8,300 ) 536,926 Changes to gross goodwill Increases recorded in business combinations 26,959 Changes in purchase price allocation (1,075 ) Changes resulting from foreign currency fluctuations (1,444 ) 24,440 December 31, 2018 Gross goodwill 569,666 Accumulated impairment loss (8,300 ) $ 561,366 Total future amortization expense related to intangible assets subject to amortization at December 31, 2018 is set forth in the table below: ( in thousands 2019 $ 52,298 2020 51,675 2021 49,297 2022 41,834 2023 17,718 Thereafter through 2031 39,226 Total future amortization expense $ 252,048 Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities consisted of the following: December 31, ( in thousands 2018 2017 Accrued expenses $ 70,386 $ 42,983 Other taxes payable 9,359 12,692 Accounts payable 8,799 4,366 Distributor commissions payable 8,194 7,697 Royalties payable 7,173 5,040 Other 1,966 2,989 Accounts payable and accrued liabilities $ 105,877 $ 75,767

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The fair values of the Company’s assets and liabilities, including cash equivalents, marketable securities, restricted investments, derivatives, and contingent considerations are measured at fair value on a recurring basis. As of and , the Company held investments in securities classified as cash equivalents. During the periods presented, the Company did not hold any investments that were in a significant unrealized loss position and no impairment charges were recorded. Realized gains and losses and interest income related to marketable securities were immaterial during all periods presented. Quoted Price in Significant Other Significant Active Market Observable Inputs Unobservable ( in thousands Total (Level 1) (Level 2) Inputs (Level 3) December 31, 2018 Cash equivalents: Money market funds $ 56,000 $ 56,000 $ — $ — Total cash equivalents $ 56,000 $ 56,000 $ — $ — December 31, 2017 Cash equivalents: Money market funds $ 27,000 $ 27,000 $ — $ — Total cash equivalents $ 27,000 $ 27,000 $ — $ — The carrying amounts of certain financial instruments such as cash and cash equivalents, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses, and other current liabilities as of December 31, 2018 and December 31, 2017 approximate their related fair values due to the short-term maturities of these instruments. The fair value of certain financial instruments was measured and classified within Level 1 of the fair value hierarchy based on quoted prices. Certain financial instruments classified within Level 2 of the fair value hierarchy include the types of instruments that trade in markets that are not considered to be active, but are valued based on quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The Company did not hold any financial instruments classified within Level 2 of the fair value hierarchy during the periods presented. Foreign Currency and Derivative Financial Instruments To manage foreign currency exposure risks, the Company uses derivatives for activities in entities that have short-term intercompany receivables and payables denominated in a currency other than the entity’s functional currency. The fair value is based on a quoted market price (Level 1). 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. Some of the Company’s reporting entities conduct a portion of their business in currencies other than the entity’s functional currency. These transactions give rise to receivables and payables that are denominated in currencies other than the entity’s functional currency. The value of these receivables and payables is subject to changes in currency exchange rates from the point at which the transactions are originated until the settlement in cash. Both realized and unrealized gains and losses in the value of these receivables and payables are included in the determination of net income. Net currency exchange losses, which includes gains and losses from derivative instruments, were $(3.7) million, $(0.9) million and $(0.3) million for the years ended December 31, 2018, 2017 and 2016, respectively, and are included in other income (expense) in the Consolidated Statements of Operations. A s of December 31, 2018, 2017, and 2016 a notional principal amount of $26.8 million, $14.3 million, and $15.1 million respectively, was outstanding to hedge currency risk relative to foreign receivables and payables. Derivative instrument net (losses) gains on the Company’s forward exchange contracts were $0.5 million, $(1.9) million, and $0.7 million for the years ended December 31, 2018, 2017 and 2016, respectively, and are included in other income (expense) in the Consolidated Statements of Operations. December 31, 2018 December 31, 2017 The Company’s currency exposures vary, but are primarily concentrated in the pound sterling the Australian dollar, the Brazilian real, the Singapore dollar, and the yen The Company does not use derivative financial instruments for speculation or trading purposes or for activities other than risk management. The Company does not require and is not required to pledge collateral for these financial instruments and does not carry any master netting arrangements to mitigate the credit risk. Fair Value of Senior Convertible Notes The fair value, based on a quoted market price (Level 1), of the Company’s outstanding Senior Convertible Notes due 2021 at December 31, 2018 and December 31, 2017 was approximately $684.8 million and $779.5 million, respectively. See Note 5 to the Consolidated Financial Statements included in this Annual Report for further discussion on the carrying value of the notes. Contingent Consideration Liabilities The fair value of contingent consideration liabilities assumed in business combinations is recorded as part of the purchase price consideration of the acquisition, and is determined using a discounted cash flow model or probability simulation model. The significant inputs of such models are not observable in the market, such as certain financial metric growth rates, volatility rates, projections associated with the applicable milestone, the interest rate, and the related probabilities and payment structure in the contingent consideration arrangement. Fair value adjustments to contingent consideration liabilities are recorded through operating expenses in the Consolidated Statement of Operations. Contingent consideration arrangements assumed by an asset purchase will be measured and accrued when such contingency is resolved. Contingent consideration liabilities were $50.4 million December 31, 2018 December 31, 2017 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 2018 2017 Fair value measurement at January 1 $ 67,941 $ 67,501 Contingent consideration liability recorded upon acquisition 3,543 32,559 Change in fair value measurement (1,517 ) (1,295 ) Changes resulting from foreign currency fluctuations 193 (224 ) Contingent consideration paid or settled (19,750 ) (30,600 ) Fair value measurement at December 31 $ 50,410 $ 67,941 During the year ended December 31, 2018, the Company paid $19.0 million in outstanding milestone obligations associated with the LessRay acquisition, of which $9.0 million related to the achievement of a commercial milestone, and $10.0 million related to the achievement of a regulatory approval milestone. In accordance with the guidance outlined in ASU 2016-15, $18.7 million of the $19.0 million represented the initial purchase price allocation and is presented as a cash outflow for financing activities on the Consolidated Statement of Cash Flows, and the remaining $0.3 million related to increased fair value adjustment is presented as a cash outflow in operating activities. During the year ended December 31, 2017, the Company recorded contingent consideration liabilities of $32.6 million in connection with certain acquisitions. Such acquisitions include the acquisition in September 2017 of a medical device company that developed interbody implants for spinal fusion using patented porous PEEK technology, which was incorporated into the Company’s portfolio of interbody implants. The Company recorded a purchase accounting fair value estimate of $31.4 million for contingent consideration liabilities related to the achievement of certain manufacturing and commercial milestones associated with that acquisition In the year ended December 31, 2017, t he Company paid the $30.0 million outstanding milestone obligation associated with the Ellipse Technologies acquisition. In accordance with the guidance outlined in ASU 2016-15, he initial purchase price allocation $11.2 million related to increased fair value adjustments is presented as a cash outflow in operating activities. Non-financial assets and liabilities measured on a nonrecurring basis Certain non-financial assets and liabilities are measured at fair value, usually with Level 3 inputs including the discounted cash flow method or cost method, on a nonrecurring basis in accordance with authoritative guidance. These include items such as nonfinancial assets and liabilities initially measured at fair value in a business combination and non-financial long-lived assets measured at fair value for an impairment assessment. In general, non-financial assets, including goodwill, intangible assets and property and equipment, are measured at fair value when there is an indication of impairment and are recorded at fair value only when any impairment is recognized. The carrying values of the Company’s capital lease obligations approximated their estimated fair value as of December 31, 2018 and 2017. The Company has obligations under certain consultancy arrangements based on achievement of specified milestones. There was no accrual as of December 31, 2018 or 2017, related to these obligations. During the year ended December 31, 2018, the Company expensed $8.9 million for a purchased in-process research and development asset which had no future alternative use. The Company also recorded a net loss of $3.8 million on strategic investments during the year ended December 31, 2018. The net loss was recorded in other income (expense), net in the Consolidated Statement of Operations included in this Annual Report.

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2018
Business Combination Description [Abstract]
Business Combinations	4. Business Combinations The Company recognizes the assets acquired, liabilities assumed, and any non-controlling interest at fair value at the date of acquisition. Certain acquisitions contained contingent consideration arrangements that required the Company to assess the acquisition date fair value of the contingent consideration liabilities, which was recorded as part of the purchase price allocation of the acquisition, with subsequent fair value adjustments to the contingent consideration recorded in the Consolidated Statements of Operations. See Note 3 Acquisitions In January 2018, the Company acquired SafePassage, a privately-held provider of IOM services, which now operates as a wholly-owned subsidiary of the Company. The acquisition was not considered material to the overall Consolidated Financial Statements. The Company provides IOM services through various subsidiaries, including SafePassage, which conduct business as NuVasive Clinical Services. The revenue generated from IOM services and support is reported as service revenue on the Consolidated Statement of Operations. The Company has completed other acquisitions that were not considered material, individually or collectively, to the overall Consolidated Financial Statements during the periods presented. These acquisitions have been included in the Consolidated Financial Statements from the respective dates of acquisition. The Company does not believe that collectively the acquisitions made during the periods presented are material to the overall financial statements. For certain acquisitions completed during the periods presented, the Company is still in the process of finalizing the purchase price allocation given the timing of the acquisitions and the size and scope of the assets and liabilities subject to valuation. While the Company does not expect material changes in the valuation outcome, certain assumptions and findings that were in place at the date of acquisition could result in changes in the purchase price allocation. Variable Interest Entities Progentix Orthobiology, B.V. In 2009, the Company purchased forty percent (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 $10.0 million in cash (the “Initial Investment”). The Company also loaned Progentix cumulatively a total of $5.3 million at an interest rate of 6% per year (the “Loan”). Concurrently, with the Initial Investment, the Company and Progentix entered into a Distribution Agreement (as amended, the “Distribution Agreement”) for a term of ten years, whereby Progentix appointed the Company as its exclusive distributor for certain Progentix products. Following the Initial Investment, in accordance with authoritative guidance, the Company determined that Progentix was a variable interest entity (“VIE”), as it did not have the ability to finance its activities without additional subordinated financial support and its equity investors would not absorb their proportionate share of expected losses and would be limited in the receipt of the potential residual returns of Progentix. In January 2018, the Company completed the acquisition of the remaining 60% of the capital stock of Progentix (the “Non-Controlling Interest Acquisition”). Subsequent to the Non-Controlling Interest Acquisition, the Company owns 100% of the capital stock of Progentix, which now operates as a wholly-owned subsidiary of the Company and is no longer accounted for as a VIE or a separate reporting unit as of the date of the Non-Controlling Interest Acquisition. In accordance with authoritative guidance, the non-controlling interest associated with Progentix was reclassified to additional paid-in capital, including the difference between the non-controlling interest and consideration paid. The Loan plus accrued interest and the related receivable between the Company and Progentix was still outstanding as of December 31, 2018. The following is a reconciliation of equity (net assets) attributable to the non-controlling interest: Year Ended December 31, ( in thousands 2018 2017 Non-controlling interests at beginning of period $ 3,845 $ 5,588 Acquired non-controlling interest reclassified to additional paid-in capital (3,845 ) — Less: net loss attributable to the non-controlling interests — (1,743 ) Non-controlling interests at end of period $ — $ 3,845 Total assets and liabilities of Progentix as a VIE included in the accompanying Consolidated Balance Sheets are as follows: December 31, ( in thousands 2018 2017 Total current assets $ — $ 670 Identifiable intangible assets, net — 8,752 Goodwill — 12,654 Accounts payable & accrued expenses — 562 Deferred tax liabilities, net — 331 Non-controlling interests — 3,845 NuVasive Clinical Services and Physician Practices The Company provides IOM services through various subsidiaries, including SafePassage, which conduct business as NuVasive Clinical Services. In providing IOM services to surgeons and healthcare facilities across the U.S., the Company maintains contractual relationships with several physician practices (“PCs”). In accordance with authoritative guidance, the Company has determined that the PCs are VIEs and therefore, the accompanying Consolidated Financial Statements include the accounts of the PCs from the date of acquisition. During the periods presented, the results of the PCs were immaterial to the Company’s financials. 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.

Indebtedness

Indebtedness	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Indebtedness	5. Indebtedness The carrying values of the Company’s Senior Convertible Notes due 2021 are as follows: ( in thousands December 31, 2018 December 31, 2017 2.25% Senior Convertible Notes due 2021: Principal amount $ 650,000 $ 650,000 Unamortized debt discount (40,117 ) (56,839 ) Unamortized debt issuance costs (7,357 ) (10,241 ) Total Senior Convertible Notes $ 602,526 $ 582,920 2.25% Senior Convertible Notes due 2021 In March 2016, the Company issued $650.0 million principal amount of unsecured Senior Convertible Notes with a stated interest rate of 2.25% and a maturity date of March 15, 2021 (the "2021 Notes"). The net proceeds from the offering, after deducting initial purchasers' discounts and costs directly related to the offering, were approximately $634.1 million. The 2021 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 satisfying the principal amount outstanding with cash and any note conversion value over the principal amount in shares of the Company's common stock. The initial conversion rate of the 2021 Notes is 16.7158 shares per $1,000 principal amount, which is equivalent to a conversion price of approximately $59.82 per share, subject to adjustments. The Company uses the treasury share method for assumed conversion of the 2021 Notes to compute the weighted average shares of common stock outstanding for diluted earnings per share. The Company also entered into transactions for convertible note hedge (the "2021 Hedge") and warrants (the "2021 Warrants") concurrently with the issuance of the 2021 Notes. The cash conversion feature of the 2021 Notes required bifurcation from the notes and was initially accounted for as an equity instrument classified to stockholders’ equity, which resulted in recognizing $84.8 million in additional paid-in-capital during 2016. The interest expense recognized on the 2021 Notes during the year ended December 31, 2018 Prior to September 15, 2020, holders may convert their 2021 Notes only under the following conditions: (a) during any calendar quarter beginning June 30, 2016, 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 2021 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 2021 Notes. From September 15, 2020 and until the close of business on the second scheduled trading day immediately preceding March 15, 2021, holders may convert their 2021 Notes at any time (regardless of the foregoing circumstances). The Company may not redeem the 2021 Notes prior to March 20, 2019. The Company may redeem the 2021 Notes, at its option, in whole or in part on or after March 20, 2019 until the close of business on the business day immediately preceding September 15, 2020 if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company delivers written notice of a redemption. The redemption price will be equal to 100% of the principal amount of such 2021 Notes to be redeemed plus accrued and unpaid interest to, but excluding, the redemption date 2021 Hedge In connection with the offering of the 2021 Notes, the Company entered into the hedge transaction with the initial purchasers of the 2021 Notes and/or their affiliates (the "2021 Counterparties") entitling the Company to purchase up to 10,865,270 shares of the Company's common stock at an initial stock price of $59.82 per share, each of which is subject to adjustment. The cost of the 2021 Hedge was $111.2 million and accounted for as an equity instrument by recognizing $111.2 million in additional paid-in-capital during 2016. The 2021 Hedge will expire on March 15, 2021. The 2021 Hedge is expected to reduce the potential equity dilution upon conversion of the 2021 Notes if the daily volume-weighted average price per share of the Company's common stock exceeds the strike price of the 2021 Hedge. An assumed exercise of the 2021 Hedge by the Company is considered anti-dilutive since the effect of the inclusion would always be anti-dilutive with respect to the calculation of diluted earnings per share. 2021 Warrants The Company sold warrants to the 2021 Counterparties to acquire up to 10,865,270 shares of the Company’s common stock. The 2021 Warrants will expire on various dates from June 2021 through December 2021 and may be settled in cash or net shares. It is the Company's current intent and policy to settle all conversions in shares of the Company’s common stock. The Company received $44.9 million in cash proceeds from the sale of the 2021 Warrants, which was recorded in additional paid-in-capital. The 2021 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 2021 Warrants, which is $80.00 per share. The Company uses the treasury share method for assumed conversion of its 2021 Warrants to compute the weighted average common shares outstanding for diluted earnings per share. 2.75% Senior Convertible Notes due 2017 In June 2011, the Company issued $402.5 million principal amount of the unsecured Senior Convertible Notes with a stated interest rate of 2.75% and a maturity date of July 1, 2017 (the “2017 Notes”). The 2017 Notes provided for settlement in cash, stock, or a combination thereof, solely at the Company’s discretion. The initial conversion rate of the 2017 Notes was 23.7344 shares per $1,000 principal amount, which is equivalent to a conversion price of approximately $42.13 per share, subject to adjustments. The Company used the treasury share method for assumed conversion of the 2017 Notes to compute the weighted average shares of common stock outstanding for diluted earnings per share. During 2016, the Company repurchased a majority of the 2017 Notes, which resulted in a cumulative loss of approximately $19.1 million recorded in other expense on the accompanying Consolidated Statements of Operations for the year ended December 31, 2016. In July 2017, the Company settled the remaining 2017 Notes upon maturity via combination settlement, which involved satisfying the principal amount outstanding with cash and any note conversion value over the principal amount in shares of the Company’s common stock The interest expense recognized on the 2017 Notes during the year ended December 31, 2017 includes $0.9 million, $1.4 million and $0.2 million for the contractual coupon interest, the accretion of the debt discount and the amortization of the debt issuance costs, respectively. The interest expense recognized on the 2017 Notes during the year ended December 31, 2016 includes $4.9 million, $7.5 million and $1.0 million for the contractual coupon interest, the accretion of the debt discount and the amortization of the debt issuance costs, respectively. The effective interest rate on the 2017 Notes was 8.0%, which includes the interest on the notes, amortization of the debt discount and debt issuance costs. Interest on the 2017 Notes began accruing upon issuance and was payable semi-annually. Concurrently, with the offering of the 2017 Notes the Company also entered into transactions for a convertible note hedge (the “2017 Hedge”) and warrants (the “2017 Warrants”). The 2017 Hedge entitled the Company to purchase up to 9,553,096 shares of the Company’s common stock at an initial price of $42.13 per share. Prior to its maturity, an assumed exercise of the 2017 Hedge by the Company was considered anti-dilutive since the effect of inclusion would always be anti-dilutive with respect to the calculation of diluted earnings per share. The 2017 Warrants entitled its holders to acquire up to 477,654 shares of the Company’s Series A Participating Preferred Stock at an initial strike price of $988.51 per share. Each share of Series A Participating Preferred Stock was convertible into 20 shares of the Company’s common stock, or up to 9,553,080 common shares in total. The 2017 Warrants were scheduled to expire on various dates from September 2017 through January 2018 with settlement in cash or net shares. The Company used the treasury share method for assumed conversion of its 2017 Warrants to compute the weighted average common shares outstanding for diluted earnings per share. In 2017, the Company exercised the 2017 Hedge and also entered into warrant termination agreements which settled the 2017 Warrants on a net share basis. Revolving Senior Credit Facility In April 2017, the Company entered into an Amended and Restated Credit Agreement (the “2017 Credit Agreement”) for a revolving senior credit facility (the “2017 Facility”), which replaced the previous Credit Agreement the Company had entered into in February 2016. The 2017 Credit Agreement provides for secured revolving loans, multicurrency loan options and letters of credit in an aggregate amount of up to $500.0 million. The 2017 Credit Agreement also contains an expansion feature, which allows the Company to increase the aggregate principal amount of the 2017 Facility provided the Company remains in compliance with the underlying financial covenants, including but not limited to, compliance with the consolidated interest coverage ratio and certain consolidated leverage ratios. The 2017 Facility matures in April 2022 (subject to an earlier springing maturity date), and includes a sublimit of $100.0 million for multicurrency borrowings, a sublimit of $50.0 million for the issuance of standby letters of credit, and a sublimit of $5.0 million for swingline loans. All assets of the Company and its material domestic subsidiaries are pledged as collateral under the 2017 Facility (subject to customary exceptions) pursuant to the term set forth in the Amended and Restated Security and Pledge Agreement (the “2017 Security Agreement”) executed in favor of the administrative agent by the Company. Each of the Company’s material domestic subsidiaries guarantees the 2017 Facility. In connection with the 2017 Facility, the Company incurred issuance costs which will be amortized over the term of the 2017 Facility. Borrowings under the 2017 Facility are used by the Company to provide financing for working capital and other general corporate purposes, including potential mergers and acquisitions. Borrowings under the 2017 Facility bear interest, at the Company’s option, at a rate equal to an applicable margin plus: (a) the applicable Eurocurrency Rate (as defined in the 2017 Credit Agreement), or (b) a base rate determined by reference to the highest of (1) the federal funds effective rate plus 0.50%, (2) the Bank of America prime rate, and (3) LIBOR for an interest period of one month plus 1.00%. The margin for the 2017 Facility ranges, based on the Company’s consolidated leverage ratio, from 0.00% to 1.00% in the case of base rate loans and from 1.00% to 2.00% in the case of Eurocurrency Rate loans. The 2017 Facility includes an unused line fee ranging, based on the Company’s consolidated leverage ratio, from 0.20% to 0.35% per annum on the revolving commitment. The 2017 Credit Agreement contains affirmative, negative, permitted acquisition and financial covenants, and events of default customary for financings of this type. The financial covenants require the Company to maintain ratios of consolidated earnings before interest, taxes, depreciation and amortization (EBITDA) in relation to consolidated interest expense and consolidated debt, respectively, as defined in the 2017 Credit Agreement. The 2017 Facility grants the lenders preferred first priority liens and security interests in capital stock, intercompany debt and all of the present and future property and assets of the Company and each guarantor. The Company is currently in compliance with the 2017 Credit Agreement covenants.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments	6. Commitments Leases The Company leases office facilities and equipment under various operating and capital lease agreements. The initial terms of these leases range from 2 years to 17 years and generally provide for periodic rent increases and renewal options. Certain leases require the Company to pay taxes, insurance and maintenance. In connection with certain operating leases, the Company has security deposits recorded and maintained as restricted cash totaling $2.4 million and $5.4 million as of December 31, 2018 and 2017, respectively. Rent expense is recognized on a straight-line basis over the term of the lease. Accordingly, rent expense recognized in excess of rent paid is reflected as a liability in the accompanying Consolidated Balance Sheets. Rent expense, including costs directly associated with the facility leases, was approximately $12.8 million, $12.6 million, and $10.6 million for the years ended December 31, 2018, 2017, and 2016, respectively. The Company’s future minimum annual lease payments under capital and operating leases, including payments for costs directly associated with the facility leases, for years ending after December 31, 2018 are as follows: Capital Operating ( in thousands Leases Leases 2019 $ 534 $ 13,750 2020 507 13,007 2021 244 10,954 2022 24 10,578 2023 5 10,515 Thereafter — 116,684 Total minimum lease payments $ 1,314 $ 175,488 Less amount representing interest (59 ) Present value of obligations under capital leases 1,255 Less current portion (449 ) Long-term capital lease obligations $ 806 Licensing and Purchasing Agreements The Company has both minimum and contingent obligations to make payments of up to $75.2 if specified future events occur or conditions are met specify milestone payment timelines Executive Severance Plans The Company has employment contracts with key executives and maintains severance plans that provide for the payment of severance and other benefits if such executives are terminated for reasons other than cause, as defined in those agreements and plans. Certain agreements call for payments that are based on historical compensation, and accordingly, the amount of the contractual commitment will change over time commensurate with the executive’s applicable earnings. At December 31, 2018, future commitments for such key executives were approximately $15.0 million. In certain circumstances, the agreements call for the acceleration of equity vesting. Those figures are not reflected in the above information.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity Common Stock There were 120,000,000 shares of common stock authorized at December 31, 2018 and 2017. Preferred Stock There are 5,000,000 shares of preferred stock authorized and none issued or outstanding at December 31, 2018 and 2017. On June 28, 2011, in connection with the issuance of the 2017 Warrants, the Company amended its Restated Certificate of Incorporation to designate 477,654 shares of the Company’s authorized preferred stock, par value $0.001 per share, as Series A Participating Preferred Stock (the “Series A Preferred Stock”). The Series A Preferred Stock will automatically convert into shares of the Company’s common stock. The holders of Series A Preferred Stock (collectively, the Preferred Holders) are entitled to receive dividends when and if declared by the Board of Directors. The preferred dividends are payable in preference and in priority to any dividends on the Company’s common stock. Shares of Series A Preferred Stock are convertible into 20 shares of common stock, subject to certain anti-dilution adjustments. Preferred Holders vote on an equivalent basis with common stockholders on an as-converted basis. The Preferred Holders are entitled to receive liquidation preferences at the rate of $648.20 per share. Liquidation payments to the Preferred Holders have priority and are made in preference to any payments to the holders of common stock. Stock-based Compensation 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"), replacing the 2004 Amended and Restated Equity Incentive Plan (the “2004 EIP”). No further awards may be granted under the 2004 EIP; however, that plan continues to govern all awards previously issued under it (of which awards remain outstanding). The 2014 EIP provides the Company with the ability to grant various types of equity awards to its workforce (including, without limitation, restricted stock units (“RSUs”), restricted stock awards, performance awards, and deferred stock awards). The 2014 EIP also provides for the issuance of performance RSUs (“PRSUs”) to be granted subject to time- and/or performance-based vesting requirements. In addition, the award agreements under the 2014 EIP generally provide for the acceleration of 50% of the unvested equity awards of all shareowners upon a change in control and the vesting of the remaining unvested equity awards for those shareowners that are involuntarily terminated within a year of the change in control. Each of the 2004 EIP and the 2014 EIP allow for “net share settlement” of certain equity awards whereby, in lieu of (i) making cash payments in satisfaction of the exercise price owed respective to non-qualified stock option awards, or (ii) open market selling award shares to generate cash proceeds for use in satisfaction of statutory tax obligations respective to an award’s settlement or exercise, the company offsets the award shares being settled in a respective transaction by the number of shares of company stock with a value equal to the respective obligation, and, in the case of taxes, making a cash payment to the respective taxing authority on behalf of the shareowner using Company cash. The net share settlement is accounted for with the cost of any award shares that are net settled being included in treasury stock and reported as a reduction in total equity at the time of settlement. In connection with the acquisition of Ellipse Technologies in February 2016, the Company assumed the Ellipse Technologies, Inc. 2015 Incentive Award Plan and the shares thereunder, subject to an equity exchange adjustment, for future awards by the Company. The compensation cost that has been included in the Consolidated Statements of Operations for the Company’s stock-based compensation plans was as follows: Year Ended December 31, ( in thousands 2018 2017 2016 Sales, marketing and administrative expense $ 22,190 $ 20,596 $ 25,466 Research and development expense 3,052 1,445 1,231 Cost of goods sold 431 350 227 Stock-based compensation expense before taxes 25,673 22,391 26,924 Related income tax benefits (6,418 ) (8,509 ) (10,770 ) Stock-based compensation expense, net of taxes $ 19,255 $ 13,882 $ 16,154 As of December 31, 2018, there was $25.1 million and $14.4 million of unrecognized compensation expense for RSUs and PRSUs, respectively, which is expected to be recognized over a weighted-average period of approximately 1.9 years and 2.6 years, respectively. In addition, as of December 31, 2018, there was $0.9 million of unrecognized compensation expense for shares expected to be issued under the ESPP which is expected to be recognized through April 2019. There was no unamortized expense for stock options as of December 31, 2018. Restricted Stock Units The total fair value of RSUs that vested during the year ended December 31, 2018, 2017, and 2016 was $8.8 million, $19.9 million and $31.2 million, respectively. Following is a summary of RSU activity for the year ended December 31, 2018: Weighted Average Number of Grant Date ( in thousands, except per share amounts Shares Fair Value Outstanding at December 31, 2017 996 $ 52.90 Granted 467 55.55 Vested (169 ) 42.94 Forfeited (180 ) 55.63 Outstanding at December 31, 2018 1,114 $ 55.25 For the majority of RSUs, shares are issued on the vesting dates net of the amount of shares needed to satisfy statutory tax withholding requirements to be paid by the Company on behalf of the employees. The total shares withheld related to vested RSUs were approximately 42,000, 103,000, and 227,000 in 2018 2017 , and 2016 , respectively, and were based on the value of the awards on their vesting dates as determined by the Company’s closing stock price. Total payments for the employees’ tax obligations to the taxing authorities related to vesting RSUs were $2.2 million, $7.2 million and $11.4 million in 2018 , 2017 and 2016 , respectively. Performance-Based Restricted Stock Units The Company has granted PRSUs since 2012 for which the ultimate issuance amount is determined by the Company’s Compensation Committee upon its certification of Company performance against a pre-determined matrix, including targets for revenue, operating margin, earnings per share and total shareholder return over pre-determined periods of time. Share payout levels range from 0% to 312.5% depending on the respective terms of an award. Based upon the company’s actual performance against the performance conditions, approximately 21,000, 76,000 and 145,000 shares of common stock vested pursuant to PRSUs in 2018, 2017 and 2016, respectively. In 2015, the Company granted PRSU awards with five-year cliff vesting terms to Gregory T. Lucier, in connection with his appointment as the Company’s Chief Executive Officer, for which the performance criteria was not based on Company or market specific performance metrics, and as such, the Company recorded the award as a long-term liability as expensed over the service period. No amounts have been paid out on this award, or are expected to become due until 2020. In November 2018, J. Christopher Barry succeeded Mr. Lucier as the Company’s Chief Executive Officer, and Mr. Lucier remained on the Company’s Board of Directors and entered into an agreement to provide services to the Company as a consultant. The PRSU awards granted to Mr. Lucier will continue to vest in accordance with the continued services provided by Mr. Lucier as a consultant and as a member of the Company’s Board of Directors through the vesting date. The total fair value of PRSUs vested during 2018, 2017, 2016 and was $2.1 million, $10.3 million and $12.6 million, respectively. Following is a summary of PRSU activity for the year ended December 31, 2018: Maximum Number ( in thousands, except per share amounts Shares of Shares Eligible to be Issued Average Grant Date Fair Value Outstanding at December 31, 2017 765 1,462 $ 52.62 Awarded at target 369 479 54.86 Vested (21 ) (21 ) 48.73 Forfeited (126 ) (262 ) 55.39 Outstanding at December 31, 2018 987 1,658 $ 56.88 For the majority of PRSUs, shares are issued on the vesting dates net of the amount of shares needed to satisfy statutory tax withholding requirements to be paid by the Company on behalf of the employees. The total shares withheld related to vesting PRSUs were approximately 8,000, 35,000 and 58,000 in 2018 2017 and 2016 respectively, and were based on the value of the awards on their vesting dates as determined by the Company’s closing stock price. Total payments for the employees’ tax obligations to the taxing authorities related to vesting PRSUs were $0.4 million, $2.5 million, and 2.7 million in 2018 2017 , and 2016 respectively. Stock Options The Company has not granted any stock options since 2011. The stock options previously granted are exercisable for a period of up to ten years after the date of grant. The aggregate intrinsic value of outstanding stock options at December 31, 2018 is based on the Company’s closing stock price on December 31, 2018 of $49.56. The Company received $1.3 million, $2.4 million and $3.0 million in proceeds from the exercise of stock options during the years ended December 31, 2018, 2017 and 2016, respectively. The total intrinsic value of stock options exercised was $2.5 million, $8.3 million, and $29.0 million during the years ended December 31, 2018, 2017 and 2016, respectively. There were no stock options that vested during the year ended December 31, 2018, 2017 or 2016. Following is a summary of stock option activity for the year ended December 31, 2018 under all stock plans: Weighted-Average Remaining Weighted Contractual Aggregate Avg. Exercise Term Intrinsic ( in thousands, except years and per share amounts Shares Price (Years) Value Outstanding at December 31, 2017 178 $ 35.41 1.33 $ 4,105 Exercised (128 ) 35.28 Cancelled (1 ) 34.49 Outstanding at December 31, 2018 49 35.76 1.52 $ 680 Exercisable at December 31, 2018 49 $ 35.76 1.52 $ 680 Vested or expected to vest at December 31, 2018 49 $ 35.76 1.52 $ 680 For the majority of stock options, shares are issued on the exercise dates net of the amount of shares needed to satisfy each of the exercise price (in lieu of cash) and statutory tax withholding requirements, the latter to be paid by the Company on behalf of the employee. The total shares withheld related to exercised stock options were approximately 65,000, 105,000, and 1,157,000 in 2018 , 2017 , and 2016, respectively, and were based on the value of the stock options on their exercise dates as determined by the Company’s closing stock price. Total cash payments for the employees’ tax obligations to the taxing authorities related to exercised stock options were $0.4 million, $2.1 million, and $10.7 million in 2018 2017 , and 2016, respectively. Employee Stock Purchase Plan The NuVasive, Inc. 2004 Amended and Restated Employee Stock Purchase Plan (the “ESPP”), provides eligible employees with a means of acquiring equity in the Company at a discounted purchase price using their own accumulated payroll deductions. Under the terms of the ESPP, employees can elect to have up to 15% of their annual compensation, up to a maximum of $21,250 per year, withheld to purchase shares of Company common stock for a purchase price equal to 154,000 The weighted average assumptions used to estimate the fair value of stock options granted and stock purchase rights under the ESPP are as follows: Year Ended December 31, 2018 2017 2016 ESPP Volatility 33 % 26 % 29 % Expected term (years) 0.5 0.5 0.5 Risk free interest rate 1.8 % 0.9 % 0.4 % Expected dividend yield — % — % — % Common Stock Reserved for Future Issuance The following table summarizes common shares reserved for issuance on exercise or conversion at December 31, 2018 ( in thousands Issued and outstanding stock options 49 Issued and outstanding RSUs and PRSUs 2,183 Available for issuance under the ESPP 1,093 Available for future grant 3,752 2021 Notes 14,396 2021 Warrants 32,596 Total shares reserved for future issuance 54,069 Pursuant to the terms of the 2014 EIP, shares subject to awards granted under the 2004 EIP may be utilized for future grants of awards under the 2014 EIP, to the extent such awards are terminated, cancelled or they expire, or shares subject thereto are withheld to cover taxes. During the year ended December 31, 2016, the Company filed a registration statement with the Securities and Exchange Commission with respect to 2.2 million of such shares for future issuance under the 2014 EIP. These shares are reflected in the number of shares available for future grants.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes Total income before income taxes summarized by region for the years ended December 31 is as follows: Year Ended December 31, ( in thousands 2018 2017 2016 United States $ 8,939 $ 76,480 $ 77,610 Foreign (216 ) (4,117 ) (12,830 ) Total income before income taxes $ 8,723 $ 72,363 $ 64,780 The income tax (benefit) provision for the years ended December 31 consists of the following: Year Ended December 31, ( in thousands 2018 2017 2016 Current: Federal $ (4,188 ) $ 5,972 $ (14,837 ) State 2,043 776 1,283 Foreign 5,972 2,793 2,350 Total current provision 3,827 9,541 (11,204 ) Deferred: Federal (5,944 ) (1,565 ) 40,363 State (7,092 ) (4,276 ) 1,455 Foreign (98,795 ) (2,223 ) (2,583 ) Total deferred provision (111,831 ) (8,064 ) 39,235 Changes in tax rate 258 (14,668 ) (216 ) Changes in valuation allowance 103,990 5,699 1,494 Total (benefit) provision $ (3,756 ) $ (7,492 ) $ 29,309 The differences between the income tax provision at the United States federal statutory tax rate and the Company’s effective tax rate for the years ended December 31 are the following: Year Ended December 31, ( in thousands 2018 2017 2016 Tax provision at federal statutory rate $ 1,832 $ 25,327 $ 22,673 Valuation allowance 103,990 5,703 1,494 Net tax benefit on international restructuring (97,028 ) — — Income tax reserves (6,717 ) 1,184 759 Income tax credits and incentives (5,525 ) (3,462 ) (3,426 ) Return to provision adjustments (4,180 ) (2,443 ) (1,188 ) Compensation expense 2,008 (5,619 ) (8,013 ) Globalization initiative 1,264 306 6,290 Nondeductible meals and entertainment 769 922 1,013 Foreign tax rate differences from federal statutory rate (688 ) 378 605 Change in tax rates 258 (14,668 ) (216 ) Acquisition related charges (221 ) (489 ) 5,167 State income tax 90 3,553 3,245 Recovery of tax basis in United States subsidiary — (19,540 ) — Other 392 1,356 906 Total (benefit) provision $ (3,756 ) $ (7,492 ) $ 29,309 Significant components of the Company’s deferred tax assets and liabilities at December 31 are composed of the following: December 31, ( in thousands 2018 2017 Deferred tax assets: Amortization $ 106,769 $ 6,742 General business and other credit carryforwards 25,846 18,928 Stock-based compensation 14,914 13,502 Inventory 12,385 10,075 Net operating loss carryforwards 7,516 14,991 Deferred rent 4,628 2,532 Original issue discount 3,322 4,606 Other 23,241 14,859 Gross deferred tax assets 198,621 86,235 Less valuation allowance (120,233 ) (16,247 ) Net deferred tax assets 78,388 69,988 Deferred tax liabilities: Acquired intangibles (42,767 ) (53,076 ) Depreciation (32,851 ) (23,132 ) Other (1,843 ) (1,752 ) Total deferred tax liabilities (77,461 ) (77,960 ) Consolidated net deferred tax assets (liabilities) $ 927 $ (7,972 ) Add deferred tax liability, net, attributable to non-controlling interests — 199 Net deferred tax assets (liabilities) $ 927 $ (7,773 ) The following table summarizes the activity related to the Company’s unrecognized tax benefits: Year Ended December 31, ( in thousands 2018 2017 2016 Gross unrecognized tax benefits at January 1 $ 25,356 $ 23,322 $ 12,448 Increases in tax positions for prior years 499 1,692 1,716 Decreases in tax positions for prior years (756 ) (24 ) (270 ) Increases in tax positions for current year relating to ongoing operations 1,913 968 6,205 Decreases in tax positions as a result of a lapse of statute of limitations (6,446 ) (402 ) — Increases in tax positions for current year relating to acquisitions 169 — 3,223 Decreases in tax positions due to settlements with taxing authorities (1,190 ) (200 ) — Gross unrecognized tax benefits at December 31 $ 19,545 $ 25,356 $ 23,322 At December 31, 2018, 2017, and 2016, $18.1 million, $24.1 million, and $12.5 million, respectively, of the Company’s total unrecognized tax benefits, if recognized, would impact the effective income tax rate. In accordance with the disclosure requirements as described in ASC Topic 740, Income Taxes The Company believes it is reasonably possible that approximately $0.8 million of its remaining unrecognized tax positions may be recognized by the end of 2019 as certain statute of limitations expire, the amount of which is primarily attributable to tax positions involving the valuation of intercompany transactions. In November 2018, the Company completed a reorganization of its international intellectual property company structure. This international restructuring generated a step-up in local tax basis, which under ASC Topic 740-10-25-20 ASU 2016-16, The Company is subject to routine compliance reviews on various tax matters around the world in the ordinary course of business. Currently, income tax audits are being conducted in the state of New York, the state of Louisiana and Germany. U.S. and most foreign jurisdictions remain subject to examination in all years due to prior year net operating losses and R&D credits. During 2018 the Company completed its tax accounting in connection with the Tax Cuts and Jobs Act (the “Act”) which was enacted into law on December 22, 2017. In 2018, the Company recorded approximately $0.3 million of tax expense attributable to 2017 during SAB 118 measurement period, which would have increased the 2017 effective tax rate by 0.5%. The Company has elected an accounting policy to treat the tax impact of the global intangible low taxed income provision of the Act as a future period charge rather than a current component of deferred taxes. The Company has a net deficit in earnings and profits from its foreign subsidiaries as of December 31, 2018. In the event the Company is required to repatriate funds from outside of the United States, such repatriation would not generate additional United States tax liabilities, but could be subject to local laws and customs generating immaterial tax consequences in the subsidiaries’ jurisdictions. At December 31, 2018, the Company had $2.3 million, $71.8 million and $6.8 million of federal, state and foreign net operating loss carryforwards, respectively, which will begin to expire in 2020. Valuation allowance reserves of $53.8 million are recorded against California net operating losses of $53.8 million due to uncertainty surrounding their realization. There were also federal and California income tax credit carryforwards of $22.3 million and $25.9 million, respectively. The federal credits will begin to expire in 2027. The California credits can be carried forward indefinitely. Valuation allowance reserves of $25.9 million are recorded against the California credits due to uncertainty surrounding their realization. Due to the “change of ownership” provision of the Tax Reform Act of 1986, utilization of the Company’s net operating loss and credit carryforwards may be subject to an annual limitation against taxable income in future periods. As a result of any future ownership changes, the annual limitation of loss and credit carryforwards may cause them to expire before ultimately becoming available to reduce future income tax liabilities.

Business Segment, Product, and

Business Segment, Product, and Geographic Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Business Segment, Product and Geographic Information	9. Business Segment, Product and Geographic Information The Company operates in one segment based upon the Company’s organizational structure, the way in which the operations and investments are managed and evaluated by the chief operating decision maker (“CODM”) as well as the lack of availability of discrete financial information at a lower level. The Company’s CODM reviews revenue at the product line offering level, and manufacturing, operating income and expenses, and net income at the Company wide level to allocate resources and assess the Company’s overall performance. The Company shares common, centralized support functions, including finance, human resources, legal, information technology, and corporate marketing, all of which report directly to the CODM. Accordingly, decision-making regarding the Company’s overall operating performance and allocation of Company resources is assessed on a consolidated basis. As such, the Company operates as one reporting segment. The Company has disclosed the revenues for each of its product line offerings to provide the reader of the financial statements transparency into the operations of the Company. The Company reports under two distinct product lines; spinal hardware and surgical support. The Company’s spinal hardware product line offerings include implants and fixation products. The Company’s surgical support product offerings include IOM services, disposables and biologics, all of which are used to aid spinal surgery. Revenue by product line was as follows: Year Ended December 31, ( in thousands 2018 2017 2016 Spinal Hardware $ 788,650 $ 737,534 $ 683,703 Surgical Support 313,064 289,151 278,429 Total Revenue $ 1,101,714 $ 1,026,685 $ 962,132 Revenue and property and equipment, net, by geographic area were as follows: Revenue Property Year Ended December 31, December 31, ( in thousands 2018 2017 2016 2018 2017 United States $ 896,152 $ 850,410 $ 831,778 $ 200,404 $ 179,891 International (excludes Puerto Rico) 205,562 176,275 130,354 38,437 35,435 Total $ 1,101,714 $ 1,026,685 $ 962,132 $ 238,841 $ 215,326

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2018
Contingencies [Abstract]
Contingencies	10. Contingencies The Company is subject to potential liabilities under government regulations and various claims and legal actions that are pending or may be asserted from time-to-time. These matters arise in the ordinary course and conduct of the Company’s business and include, for example, commercial, intellectual property, environmental, securities and employment matters. The Company intends to continue to defend itself vigorously in such matters and when warranted, take legal action against others. Furthermore, the Company regularly assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its financial statements. During the year ended December 31, 2018 During the year ended December 31, 2017, the Company paid $4.5 million for the settlement of fees associated with the outcome of the litigation matter with . During the year December 31, 2016, the Company settled its ongoing litigation with Medtronic. As a result of the settlement, the Company paid $45.0 million to Medtronic and accordingly recorded a gain of $43.3 million related to the settlement by reducing its previous accrual of $88.3 million related to the matter. An estimated loss contingency is accrued in the Company’s financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Based on the Company’s assessment, it has adequately accrued an amount for contingent liabilities currently in existence. The Company does not accrue amounts for liabilities that it does not believe are probable or that it 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 the Company’s current accruals, and it is possible that its 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 Securities Litigation On August 28, 2013, a purported securities class action lawsuit was filed in the U.S. District Court for the Southern District of California naming the Company 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 operative 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, Brad Mauss, the lead plaintiff in the case, filed an Amended Class Action Complaint for Violations of the Federal Securities Laws. The Company answered the complaint on August 25, 2016, and discovery commenced. The plaintiffs filed motions for class certification on October 28, 2016 and the Company’s opposition papers were filed on January 9, 2017. On March 22, 2017, the court issued an order granting class certification. The Company filed a petition to appeal the order granting class certification with the U.S. Court of Appeals for the Ninth Circuit (the “Ninth Circuit”) on April 5, 2017 and the plaintiffs filed an opposition to the petition. On August 15, 2017, the Ninth Circuit denied the Company’s petition. The Company filed a motion for summary judgment on September 8, 2017. On February 1, 2018, the court entered an order denying the Company’s motion for summary judgment. On February 13, 2018, the Company entered into a memorandum of understanding with the plaintiffs to settle the case for $7.9 million. On March 23, 2018, the parties executed a stipulation of settlement, which was preliminarily approved by the court on June 11, 2018. On December 6, 2018, the court issued an order and judgment granting final approval of the settlement. The settlement of $7.9 million was fully funded by insurance proceeds and includes the dismissal of all claims against the Company and the named individuals in the lawsuit without any liability or wrongdoing attributed to them. The Company no longer has any remaining liability related to this matter as of December 31, 2018. Madsen Medical, Inc. Litigation On February 19, 2016, an unfavorable jury verdict was delivered against the Company in its litigation in the U.S. District Court for the Southern District of California against Madsen Medical, Inc. (“MMI”), a former sales agent. Specifically, the jury awarded MMI $7.5 million in lost profits for tortious interference, $14.0 million for unjust enrichment, $20.0 million in punitive damages, and approximately $0.3 million in damages for breach of contract. he trial court entered judgment in favor of MMI in the amount of $27.8 million, which amount excluded the $14.0 million disgorgement awarded by the jury As of December 31, 2017, the Company believed that the outcome of the case did not constitute a probable nor an estimable loss associated with the litigation, but rather a reasonably possible loss. The Company, based on its own assessment as well as that of outside counsel, believed that it was probable upon appeal the judgment would be vacated. Accordingly, the Company did not record a loss contingency at December 31, 2017, but assessed a reasonable range of potential loss, which would be from zero to the current amount entered as a judgment, as well as attorney’s fees and interest. Following the April 12, 2018 oral argument, the Company believed that the prior judgments against it, in part or as a whole, may be upheld. Accordingly, at March 31, 2018, the Company believed that the outcome of the case constituted a probable loss. While the actual amount of the probable loss was not known, the Company assessed a range of potential loss in accordance with Accounting Standards Codification 450, Contingencies, which would be from zero to $29.0 million, and recorded an additional estimated loss contingency in the amount of $29.0 million as a current litigation liability in the Consolidated Balance Sheet as of March 31, 2018, resulting in an aggregate litigation liability of $29.0 million accrued for this matter. In May 2018, the Company entered into an agreement to settle all outstanding matters with MMI for $27.8 million. The Company has paid the settlement amount and no longer has any remaining liability related to this matter as of December 31, 2018.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Regulatory Matter [Abstract]
Regulatory Matters	11. Regulatory Matters On August 31, 2015, the Company received a civil investigative demand (“CID”) issued by the Department of Justice (“DOJ”) pursuant to the federal False Claims Act. The CID requires the delivery of a wide range of documents and information related to an investigation by the DOJ concerning allegations that the Company assisted a physician group customer in submitting improper claims for reimbursement and made improper payments to the physician group in violation of the Anti-Kickback Statute. The Company is cooperating with the DOJ in regards to this matter. No assurance can be given as to the timing or outcome of this investigation. As of December 31, 2018, the probable outcome of this matter 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 matter. On June 9, 2017, the Company received a 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 sought discovery of documents for the period January 2014 through June 2017, primarily associated with sales to a particular customer and relationships related to that customer account. In February 2019, the Company received notice that the OIG had concluded its investigation and is not pursuing the matter further.

Quarterly Data (unaudited)

Quarterly Data (unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (unaudited)	12. Quarterly Data (unaudited) The following quarterly financial data, in the opinion of management, reflects all adjustments, consisting of normal recurring adjustments necessary, for a fair presentation of results for the periods presented: Year Ended December 31, 2018 (1) (2) (3) ( in thousands, except per share amounts First Quarter Second Quarter Third Quarter Fourth Quarter Revenue $ 260,522 $ 281,564 $ 271,301 $ 288,327 Gross profit 186,708 204,508 197,141 202,198 Consolidated net (loss) income (27,132 ) 11,531 15,923 12,157 Basic net (loss) income per common (0.53 ) 0.22 0.31 0.24 Diluted net (loss) income per common share (0.53 ) 0.22 0.30 0.23 Year Ended December 31, 2017 (4) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue $ 249,013 $ 259,399 $ 247,051 $ 271,222 Gross profit 187,570 193,213 181,544 195,917 Consolidated net income 11,983 11,735 33,096 23,041 Net income attributable to NuVasive, Inc. 12,426 12,167 33,528 23,477 Basic net income per common share attributable to NuVasive, Inc. 0.25 0.24 0.66 0.46 Diluted net income per common share attributable to NuVasive, Inc. 0.22 0.21 0.64 0.45 (1) The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion. (2) The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion. (3) Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc (4) The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
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’s principal product offering includes a minimally disruptive surgical platform called Maximum Access Surgery, or MAS. 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 safe and reproducible outcomes for the surgeon and the patient. The platform includes the Company’s proprietary software-driven nerve detection and avoidance systems and Intraoperative Monitoring (“IOM”) services and support; MaXcess, an integrated split-blade retractor system; and a wide variety of specialized implants and biologics. To assist with surgical procedures, the Company offers a technology platform called Integrated Global Alignment (“iGA”); in which products and computer assisted technology under the MAS platform help achieve more precise spinal alignment. The individual components of the MAS platform, and many of the Company’s products, can also be used in open or traditional spine surgery. The Company continues to focus 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 procedurally integrated solutions use innovative, technological advancements and the MAS platform to provide surgical efficiency, operative reliability, and procedural versatility. The Company offers a range of implants for spinal surgery, which include its porous titanium and polyetheretherketone (“PEEK”) implants under its Advanced Materials Science portfolio, fixation devices such as customizable rods, plates and screws, bone allograft in patented saline packaging, allogeneic and synthetic biologics, and disposables used in IOM. The Company makes available MAS instrument sets, MaXcess and neuromonitoring systems to hospitals to facilitate surgeon access to the spine to perform restorative and fusion procedures using the Company’s implants and fixation devices. The Company sells MAS instrument sets, MaXcess and neuromonitoring systems to hospitals, however, such sales are immaterial to the Company’s results of operations. The Company also designs and sells expandable growing rod implant systems that can be non-invasively lengthened following implantation with precise, incremental adjustments via an external remote controller using magnetic technology called MAGnetic External Control, or MAGEC, which allows for the minimally invasive treatment of early-onset and adolescent scoliosis. This technology is also the basis for the Company’s PRECICE limb lengthening system, which allows for the correction of long bone limb length discrepancy, as well as enhanced bone healing in patients that have experienced traumatic injury. The Company continues to develop a wide variety of projects which broaden its MAS and other product platforms and advance the applications of its unique technology into procedurally integrated surgical solutions that improve clinical and economic outcomes, including Pulse, a surgical automation platform which incorporates neuromonitoring, surgical planning, rod bending, imaging, navigation, and other automation. Pulse is a combined hardware and software platform designed to achieve surgical efficiencies via real-time feedback to aid in clinical decision making and to optimize the procedural workflow in the operating room. The Company continues to pursue business and technology acquisition targets and strategic relationships.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying 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 non-controlling interest at the acquisition date and classifies the amounts attributable to non-controlling interest separately in equity in the Company's 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 Company has reclassified historically presented revenue and cost of revenue to conform to the current year presentation, which now reflects revenue and costs allocated to the Company’s product and service offerings. These reclassifications had no impact on previously reported results of operations. Additionally, as required by Accounting Standards Update 2014-09 Revenue from Contracts with Customers Revenue from Contracts with Customers
Use of Estimates	Use of Estimates To prepare financial statements in conformity with generally accepted accounting principles (“GAAP”) accepted in the United States, management must make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Recently Accounting Pronouncements Not Yet Adopted And Recently Adopted Accounting Standards	Recent Accounting Pronouncements Not Yet Adopted In Leases, Leases Leases In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments – Credit Losses In January 2017, the FASB issued Accounting Standards Update No. 2017-04, Intangibles – Goodwill and Other In July 2017, the FASB issued Accounting Standards Update No. 2017-11, Earnings Per Share, Distinguishing Liabilities from Equity, Derivatives and Hedging Derivatives and Hedging In August 2018, the FASB issued Accounting Standards Update No. 2018-13, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement In September 2018, the FASB issued Accounting Standards Update No. 2018-15, Intangible – Goodwill and Other – Internal-Use Software Recently Adopted Accounting Standards In May 2014, the FASB issued ASU 2014-09, an updated standard on revenue recognition. The standard effectively replaces Accounting Standards Codification 605 Revenue Recognition (“ASC 605”) with ASC 606. In summary, the changes to the guidance in revenue recognition under ASC 606 focuses on the existence of a contract with the customer (whether written, oral, or implied by an entity’s customary business practices), the concept that the performance obligation is fulfilled when the customer obtains control of the asset/service, versus the transfer of risk and reward, and the requirement that variable consideration (including rebates, discounts, etc.) and incremental costs must be estimated and recognized in the amount that is expected or most likely to be realized over the term of the contract fulfillment. Prior to the adoption of ASC 606, the Company recognized revenue in accordance with ASC 605 when all four of the following criteria were met: (i) persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured. Specifically, revenue from the sale of implants, biologics and disposables was generally recognized upon a purchase order from the hospital or acknowledgment from the hospital indicating product use or implantation or upon shipment to third-party customers who immediately accepted title. Revenue from the sale of instrument sets was recognized upon receipt of a purchase order and the subsequent shipment to customers who immediately accepted title. Revenue from neuromonitoring services was recognized in the period the service was performed for the amount of payment expected to be received. The Company adopted ASC 606 as of January 1, 2018, electing full retrospective method of adoption, which resulted in a change in its accounting policy for revenue recognition and related adjustments to the Consolidated Financial Statements for all periods presented. The Company applied the practical expedients permitted under ASC 606 for which (i) contracts with customers originating prior to January 1, 2016 do not require disclosure for the amount of consideration allocated to remaining performance obligations or an explanation of when the Company expects to recognize that amount as revenue; (ii) contracts beginning and completing in the same annual reporting period need not be restated; and (iii) hindsight for estimating variable consideration for completed contracts is permitted. The Company recognizes revenue from spinal surgery hardware and ancillary products at a point in time in two types of transactions: (i) procedural based transactions with products used during surgery defined as “charge sheet orders”, and (ii) shipping transactions which represent the stocking of product or the purchase of instrumentation to support future surgeries defined as “stocking and capital orders.” The Company also recognizes revenue at a point in time associated with surgical-related servicing procedures, including neuromonitoring services which are defined as “surgical-related services.” Other sources of revenue, such as leasing revenue and royalties, are immaterial to the Consolidated Financial Statements. For charge sheet orders, the sale occurs when the surgery is performed and a charge sheet is submitted to the Company by its sales representative identifying the products consumed during the surgery. The charge sheet, as signed by the hospital, serves as a confirmation and acknowledgement of the Company’s products consumed during a surgery. Under ASC 605, persuasive evidence of an arrangement and delivery of product was deemed to have occurred once the charge sheet was processed, and an associated authorization or acknowledgement from the customer was received. Under ASC 606, the Company’s charge sheet orders are considered to be a contract with a customer when a surgery is scheduled with the Company as requested by the hospital or surgeon, and the products are consumed during the surgery or implanted into the patient. Revenue recognition under ASC 606 occurs upon completion of the Company’s performance obligation, which occurs upon consumption of the products during surgery and receipt of the charge sheet. In the event that information related to the surgical event and consumption of product is not readily available the Company recognizes revenue upon a purchase order from the hospital or acknowledgment from the hospital indicating product use. For stocking and capital orders, under ASC 605, delivery was deemed to have occurred when the title, including all risks and rewards of ownership of the products specified in the sales agreement had passed to the buyer. Accordingly, title, including all risks and rewards of ownership, passed based on the shipping terms. Under ASC 606, the Company’s stocking and capital order performance obligation is considered to be satisfied when the buyer assumes control of the asset, either upon shipment or delivery depending on the terms, and ability to direct the use of the asset as appropriate without the Company’s consent. Under both ASC 605 and ASC 606, revenue from surgical-related services, such as neuromonitoring services, is recognized in the period the service is performed based on the delivery of a services report to the customer. The Company recognizes revenue for the amount of payment expected to be received. The Company bills either hospitals or insurance companies for different aspects of the service, as applicable. Revenue from hospitals is recognized based on agreed upon pricing. Revenue from insurance companies is recognized using the expected value method, as the Company bills at a gross rate which is generally not the rate ultimately collected. Under ASC 605, the Company has historically estimated the amounts of returns, trade-ins, discounts, rebates, credits or incentives as offsets to the total transaction price or revenue associated with the sale. In limited situations, when historical information was not available or reliable, the Company would defer revenue recognition until completion of all performance obligations. Under ASC 606, the Company analyzes sales that could include variable consideration, and estimates the expected or most likely amount of revenue after returns, trade-ins, discounts, rebates, credits, and incentives. In making these estimates, the Company considers whether the amount of variable consideration is constrained and is included in revenue only to the extent that it is probable that a significant reversal of the revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The Company earns sales-based royalty revenue over time from sales of products using existing biologics intellectual property (“IP”) that is out-licensed to certain companies. Under ASC 605, royalty revenue was recognized as earned and when collection was reasonably assured and was generally estimated and recorded in the same period as the sales that generated the royalty obligation. ASC 606 provides an exception for sales or usage-based royalties from the guidance for accounting for variable consideration, allowing the royalty revenue from the license of IP to be recognized when the performance obligation has been satisfied and the subsequent sale has occurred. Therefore, the Company estimates monthly royalty revenue as its performance obligation is satisfied. The Company does not expect a significant impact to royalty revenue under the adoption of ASC 606 as it has historically estimated and accrued royalty revenue in the period earned. The Company historically expensed incremental costs, such as commissions associated with sales contracts, as incurred. Under ASU 2014-09, ASC 340-40, Other Assets and Deferred Costs – Contracts with Customers As a result of the full retrospective method of adoption of ASC 606, the Company recorded a $1.6 million adjustment to January 1, 2016 accumulated deficit. The cumulative effect of the change on retained earnings as of December 31, 2017 for the full retrospective method of adoption of ASC 606 was $0.3 million. The following tables summarize in a condensed presentation the impact of the adoption of ASC 606 on the Company’s previously reported Consolidated Balance Sheet as of December 31, 2017, the Consolidated Statements of Operations and Comprehensive Income for the years ended December 31, 2017 and 2016, and the Consolidated Statements of Cash Flows for the years ended December 31, 2017 and 2016. NUVASIVE, INC. CONSOLIDATED BALANCE SHEET (in thousands) As of December 31, 2017 As reported Adjustments As Adjusted Accounts receivable, gross $ 212,709 $ 537 [a] $ 213,246 Allowances on accounts receivable (13,669 ) 643 [b] (13,026 ) Inventory, net 247,245 (107 ) [c] 247,138 Other current assets 112,705 — 112,705 Total current assets 558,990 1,073 560,063 Remaining other assets 1,080,077 — 1,080,077 Total assets $ 1,639,067 $ 1,073 $ 1,640,140 Accounts payable and accrued liabilities 75,076 691 [d] 75,767 Accrued payroll and related expenses 55,582 36 [e] 55,618 Other current liabilities 30,010 — 30,010 Total current liabilities 160,668 727 161,395 Deferred and income tax liabilities, non-current 18,786 84 [f] 18,870 Other long-term liabilities 660,459 — 660,459 Total NuVasive, Inc. stockholders’ equity 795,309 262 [g] 795,571 Non-controlling interests 3,845 — 3,845 Total equity 799,154 262 799,416 Total liabilities and equity $ 1,639,067 $ 1,073 $ 1,640,140 [a] Represents cumulative impact from January 1, 2016 to the period presented on accounts receivable for the full retrospective method of adoption of ASC 606. [b] Represents cumulative impact from January 1, 2016 to the period presented on allowances on accounts receivable for the full retrospective method of adoption of ASC 606. [c] Represents cumulative impact from January 1, 2016 to the period presented on inventory for the full retrospective method of adoption of ASC 606. [d] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable and accrued returns for the full retrospective method of adoption of ASC 606. [e] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable for the full retrospective method of adoption of ASC 606. [f] Represents cumulative impact from January 1, 2016 to the period presented on deferred tax liabilities for the full retrospective method of adoption of ASC 606. [g] Represents cumulative impact from January 1, 2016 to the period presented on retained earnings for the full retrospective method of adoption of ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands, except per share amounts) Year ended December 31, 2017 As reported Adjustments As adjusted Revenue Product revenue $ 941,816 $ (2,835 ) [a] $ 938,981 Service revenue 87,704 — 87,704 Total revenue 1,029,520 (2,835 ) 1,026,685 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 207,874 (567 ) [b] 207,307 Cost of services 61,134 — 61,134 Total cost of revenue 269,008 (567 ) 268,441 Gross profit 760,512 (2,268 ) 758,244 Operating expenses: Sales, marketing and administrative 539,913 (406 ) [c] 539,507 Other operating expenses 107,251 — 107,251 Total operating expenses 647,164 (406 ) 646,758 Total interest and other expense, net (39,123 ) — (39,123 ) Income tax benefit 7,038 454 [d] 7,492 Consolidated net income $ 81,263 $ (1,408 ) [e] $ 79,855 Add back net loss attributable to non-controlling interests $ (1,743 ) $ — $ (1,743 ) Net income attributable to NuVasive, Inc. $ 83,006 $ (1,408 ) [e] $ 81,598 Net income per share attributable to NuVasive, Inc.: Basic $ 1.63 $ (0.03 ) [f] $ 1.60 Diluted $ 1.50 $ (0.02 ) [f] $ 1.48 Comprehensive income attributable to NuVasive, Inc. $ 86,704 $ (1,408 ) [e] $ 85,296 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Revenue Product revenue $ 893,484 $ 60 [a] $ 893,544 Service revenue 68,588 — 68,588 Total revenue 962,072 60 962,132 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 195,593 12 [b] 195,605 Cost of services 44,500 — 44,500 Total cost of revenue 240,093 12 240,105 Gross profit 721,979 48 722,027 Operating expenses: Sales, marketing and administrative 533,624 (24 ) [c] 533,600 Other operating expenses 64,828 — 64,828 Total operating expenses 598,452 (24 ) 598,428 Total interest and other expense, net (58,819 ) — (58,819 ) Income tax expense (29,282 ) (27 ) [d] (29,309 ) Consolidated net income $ 35,426 $ 45 [e] $ 35,471 Add back net loss attributable to non-controlling interests $ (1,721 ) $ — $ (1,721 ) Net income attributable to NuVasive, Inc. $ 37,147 $ 45 [e] $ 37,192 Net income per share attributable to NuVasive, Inc.: Basic $ 0.74 $ 0.00 [f] $ 0.74 Diluted $ 0.69 $ 0.00 [f] $ 0.69 Comprehensive income attributable to NuVasive, Inc. $ 38,628 $ 45 [e] $ 38,673 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2017 As reported Adjustments As adjusted Consolidated net income $ 81,263 $ (1,408 ) [a] $ 79,855 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 5,718 (96 ) [b] 5,622 Deferred income tax benefit (12,384 ) (454 ) [c] (12,838 ) Other adjustments to reconcile net income 180,666 — 180,666 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (29,389 ) 2,779 [d] (26,610 ) Inventory (35,300 ) (567 ) [e] (35,867 ) Prepaid expenses and other current assets (12,681 ) [f] — (12,681 ) Accounts payable and accrued liabilities (16,617 ) (141 ) [g] (16,758 ) Litigation liability 8,150 — 8,150 Accrued payroll and related expenses 4,088 (113 ) [g] 3,975 Income taxes 3,455 — 3,455 Net cash provided by operating activities 176,969 — 176,969 Net cash used in investing activities (174,861 ) — (174,861 ) Net cash used in financing activities (87,028 ) — (87,028 ) Effect of exchange rate changes on cash 2,070 — 2,070 Decrease in cash, cash equivalents and restricted cash $ (82,850 ) $ — $ (82,850 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Consolidated net income $ 35,426 $ 45 [a] $ 35,471 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 11,408 44 [b] 11,452 Deferred income tax expense 26,265 27 [c] 26,292 Other adjustments to reconcile net income 188,371 — 188,371 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (33,250 ) (171 ) [d] (33,421 ) Inventory (22,636 ) 12 [e] (22,624 ) Prepaid expenses and other current assets (3,875 ) [f] — (3,875 ) Accounts payable and accrued liabilities 12,325 51 [g] 12,376 Litigation liability (88,450 ) — (88,450 ) Accrued payroll and related expenses 8,849 (8 ) [g] 8,841 Income taxes 23,652 — 23,652 Net cash provided by operating activities 158,085 — 158,085 Net cash used in investing activities (304,885 ) — (304,885 ) Net cash provided by financing activities 110,823 — 110,823 Effect of exchange rate changes on cash (929 ) — (929 ) Decrease in cash, cash equivalents and restricted cash $ (36,906 ) $ — $ (36,906 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Classification of Certain Cash Receipts and Cash Payments In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Restricted Cash In January 2017, the FASB issued Accounting Standards Update No. 2017-01, Clarifying the Definition of a Business In February 2017, the FASB issued Accounting Standards Update No. 2017-05, Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets In May 2017, the FASB issued Accounting Standards Update No. 2017-09, Compensation – Stock Compensation In March 2018, the FASB issued Accounting Standards Update No. 2018-05, Income taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 In June 2018, the FASB issued Accounting Standards Update No. 2018-07, Compensation – Stock Compensation
Revenue Recognition	Revenue Recognition In accordance with ASC 606 guidance, the Company recognizes revenue upon the transfer of goods or services to a customer at an amount that reflects the expected consideration to be received in exchange for those goods or services. The principles in ASC 606 are applied using the following five steps: (i) identify the contract with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) the Company satisfies its performance obligation(s). Specifically, revenue from the sale of implants and disposables is generally recognized at an amount that reflects the expected consideration upon notice that the Company’s products have been used in a surgical procedure or upon shipment to a third-party customer assuming control of the products. Revenue from neuromonitoring services is recognized in the period the service is performed for the amount of consideration expected to be received.
Accounts Receivable and Related Valuation Accounts	Accounts Receivable and Related Valuation Accounts Accounts receivable in the accompanying Consolidated Balance Sheets are presented net of allowances for doubtful accounts. In addition, the Company establishes a liability for estimated sales returns and a reserve for price adjustments that are recorded as a reduction to revenue. The liability and reserve are maintained to account for the future product returns and price adjustments of products sold in the current period.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers Financial instruments, which potentially subject the Company to concentrations of credit risk, consist primarily of cash and cash equivalents, marketable securities and accounts receivable. The Company limits its exposure to credit loss by placing its cash and investments with high credit quality financial institutions. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. The Company has a diverse customer base and no single customer represented greater than ten percent of sales or accounts receivable for any of the periods presented.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist principally of cash and cash equivalents, marketable securities, restricted investments, derivatives, contingent consideration liabilities, accounts receivable, accounts payable, accrued expenses, and Senior Convertible Notes. The Company measures certain assets and liabilities in accordance with authoritative guidance which requires fair value measurements to 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 the levels of the fair value measurement hierarchy during the years presented.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash and have an original maturity of three months or less at the time of purchase to be cash equivalents.
Inventory	Inventory Net inventory as of December 31, 2018 consisted of $259.4 million of finished goods, $5.0 million of work in progress and $8.8 million of raw materials. Net inventory as of December 31, 2017 consisted of $232.3 million of finished goods, $9.8 million of work in progress and $5.0 million of raw materials. Finished goods include specialized implants and disposables and are stated at the lower of cost or market determined by utilizing a standard cost method, which includes assessment of capitalized variances, which approximates the weighted average cost. Work in progress and raw materials represent the underlying material, and labor for work in progress, that ultimately yield finished goods upon completion and are subject to lower of cost or market. The Company reviews the components of its inventory on a periodic basis for excess and obsolescence and adjusts inventory to its net realizable value as necessary. Excess and Obsolete Inventory The Company provides an inventory reserve for estimated obsolescence and excess inventory based upon historical turnover and assumptions about future demand for its products and market conditions. The Company’s allograft products have shelf lives ranging from two to five years and are subject to demand fluctuations based on the availability and demand for alternative products. The Company’s inventory, which consists primarily of disposables and specialized implants, is at risk of obsolescence following the introduction and development of new or enhanced products. The Company’s estimates and assumptions for excess and obsolete inventory are reviewed and updated on a quarterly basis. The estimates the Company uses for demand are also used for near-term capacity planning and inventory purchasing and are consistent with its revenue forecasts. Increases in the reserve for excess and obsolete inventory result in a corresponding charge to cost of products sold. Historically, the Company’s reserves have been adequate to cover losses.
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Company’s goodwill represents the excess of the cost over the fair value of net assets acquired from its business combinations. The determination of the value of goodwill and intangible assets arising from business combinations and asset acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including capitalized Intangible assets acquired in a business combination that are used for in-process research and development activities are considered indefinite lived until the completion or abandonment of the associated research and development efforts. Upon reaching the end of the relevant research and development project, the Company will amortize the acquired IPR&D over its estimated useful life or expense the acquired in-process research and development should the research and development project be unsuccessful with no future alternative use. Goodwill and IPR&D are not amortized; however, they are assessed for impairment using fair value measurement techniques on an annual basis or more frequently if facts and circumstance warrant such a review. The goodwill or IPR&D are considered to be impaired if the Company determines that the carrying value of the reporting unit or IPR&D exceeds its respective fair value. The Company performs its goodwill impairment analysis at the reporting unit level, which aligns with the Company’s reporting structure and availability of discrete financial information. If a quantitative assessment is performed the evaluation includes management estimates of cash flow projections based on internal future projections . Key assumptions for these projections include revenue growth, future gross and operating margin growth, and its weighted cost of capital and terminal growth rates. The revenue and margin growth is based on increased sales of new and existing products as the Company maintains investments in research and development. Additional assumed value creators may include increased efficiencies from capital spending. The resulting cash flows are discounted using a weighted average cost of capital. Operating mechanisms and requirements to ensure that growth and efficiency assumptions will ultimately be realized are also considered in the evaluation, including timing and probability of regulatory approvals for Company products to be commercialized. The Company’s market capitalization is also considered as a part of its analysis. The Company’s annual evaluation for impairment of goodwill consists of one reporting unit. In accordance with the Company’s policy, the Company completed its most recent annual evaluation for impairment as of October 1, 2018 using the qualitative assessment and determined that no impairment existed. In addition, no indicators of impairments were noted through and consequently, no impairment charge has been recorded during the year. Intangible assets with a finite life, such as acquired technology, customer relationships, manufacturing know-how, licensed technology, supply agreements and certain trade names and trademarks, are amortized on a straight-line basis over their estimated useful life, ranging from 1 to 17 years. In determining the useful lives of intangible assets, the Company considers the expected use of the assets and the effects of obsolescence, demand, competition, anticipated technological advances, changes in surgical techniques, market influences and other economic factors. For technology based intangible assets, the Company considers the expected life cycles of products which incorporate the corresponding technology. Trademarks and trade names that are related to products are assigned lives consistent with the period in which the products bearing each brand are expected to be sold. The Company evaluates its intangible assets with finite lives for indications of impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Factors that could trigger an impairment review include significant under-performance relative to expected historical or projected future operating results, significant changes in the manner of the Company’s use of the acquired assets or the strategy for the Company’s overall business or significant negative industry or economic trends. If this evaluation indicates that the value of the intangible asset may be impaired, the Company makes an assessment of the recoverability of the net carrying value of the asset over its remaining useful life. If this assessment indicates that the intangible asset is not recoverable, based on the estimated undiscounted future cash flows of the technology over the remaining amortization period, the Company reduces the net carrying value of the related intangible asset to fair value and may adjust the remaining amortization period. See Note 2 to the Consolidated Financial Statements included in this Annual Report for further discussion on goodwill and intangible assets.
Property and Equipment	Property and Equipment Property and equipment are carried at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, ranging from 2 to 20 years. The Company depreciates leasehold improvements over their estimated useful lives or the term of the applicable lease, whichever is shorter. Leased property meeting certain capital lease criteria is capitalized, and the net present value of the related lease payments is recorded as a liability. Amortization of assets under capital leases is recorded using the straight-line method over the shorter of the estimated useful lives or the lease terms. The Company reviews property, plant and equipment for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. An impairment loss would be recognized when estimated future undiscounted cash flows relating to the asset are less than its carrying amount. An impairment loss is measured as the amount by which the carrying amount of an asset exceeds its fair value.
Income Taxes	Income Taxes The asset and liability approach is used to recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Tax law and rate changes are reflected in income in the period such changes are enacted. The Company includes interest and penalties related to income taxes, including unrecognized tax benefits, within income tax expense. During 2018 the Company completed its tax accounting in connection with the Act which was enacted into law on December 22, 2017. In 2018, the Company recorded approximately $0.3 million of tax expense attributable to 2017 during the SAB 118 measurement period, which would have increased the 2017 effective tax rate by 0.5%. The Company has elected an accounting policy to treat the tax impact of the global intangible low taxed income provision of the Act as a future period charge rather than a current component of deferred taxes. The Company’s income tax returns are based on calculations and assumptions that are subject to examination by the Internal Revenue Service and other tax authorities. In addition, the calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax regulations. The Company recognizes liabilities for uncertain tax positions based on a two-step process. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon settlement. While the Company believes it has appropriate support for the positions taken on its tax returns, the Company regularly assesses the potential outcomes of examinations by tax authorities in determining the adequacy of its provision for income taxes. The Company continually assesses the likelihood and amount of potential revisions and adjusts the income tax provision, income taxes payable and deferred taxes in the period in which the facts that give rise to a revision become known. Significant judgment is required in determining the Company’s provision for income taxes, deferred tax assets and liabilities and the valuation allowance recorded against net deferred tax assets. Deferred tax assets and liabilities are determined using the enacted tax rates in effect for the years in which those tax assets are expected to be realized. A valuation allowance is established when it is more likely than not the future realization of all or some of the deferred tax assets will not be achieved. The evaluation of the need for a valuation allowance is performed on a jurisdiction-by-jurisdiction basis, and includes a review of all available positive and negative evidence. Factors reviewed include projections of pre-tax book income for the foreseeable future, determination of cumulative pre-tax book income after permanent differences, earnings history, and reliability of forecasting. Based on the Company’s review, it concluded that it was more likely than not that the Company would be able to realize the future benefits of its domestic and foreign deferred tax assets, with the exceptions of the state of California, Malta and Brazil. This conclusion was based on historical and projected operating performance, as well as the Company’s expectation that its operations will generate sufficient taxable income in future periods to realize the tax benefits associated with the deferred tax assets within the statutory carryover periods. Due to low state apportionment, large net operating losses and the generation of sizeable research credits in California, the Company concluded that it is not more likely than not that it will be able to utilize its California deferred tax assets. Therefore, the Company has maintained a full valuation allowance on its California deferred tax assets as of December 31, 2018. Due to a history of losses in Malta and Brazil, and the lack of alternative sources of future taxable income, the Company has established a full valuation allowance against these entities’ deferred tax assets as of December 31, 2018. The Company will continue to assess the need for a valuation allowance on its deferred tax assets by evaluating both positive and negative evidence that may exist. Any adjustment to the net deferred tax asset valuation allowance would be recorded in the statement of operations for the period that the adjustment is determined to be required. See Note 8 to the Consolidated Financial Statements included in this Annual Report for further discussion on income taxes.
Loss Contingencies	Loss Contingencies An estimated loss contingency is accrued and disclosed in the Company’s financial statements if it is probable or disclosed if it is reasonably possible that a liability has been incurred and the amount of the loss can be reasonably estimated. Based on the Company’s assessment, it has adequately accrued an amount for contingent liabilities currently in existence. The Company does not accrue amounts for liabilities that it does not believe are probable and only discloses those matters it considers material to its overall financial position. In most cases, significant judgment is required to estimate the amount and timing of a loss to be recorded. The Company is involved in a number of legal actions arising in the normal course of business. The outcomes of these legal actions are not within the Company’s complete control and may not be known for prolonged periods of time. In some actions, the claimants seek damages as well as other relief, including injunctions barring the sale of products that are the subject of the lawsuit, that could require significant expenditures or result in lost revenues. 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 the Company’s current accruals, and it is possible that its 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. See Note 10 to the Consolidated Financial Statements included in this Annual Report for further discussion on legal proceedings.
Comprehensive Income	Comprehensive Income Comprehensive income is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. Comprehensive income includes net of tax, unrealized gains or losses on the Company’s marketable securities and foreign currency translation adjustments. The cumulative translation adjustments included in accumulated other comprehensive loss were $8.6 million, $6.9 million, and $10.6 million at December 31, 2018, 2017, and 2016, respectively.
Research and Development	Research and Development Research and development costs are expensed as incurred. To the extent the Company purchases research and development assets with a future alternative use the Company will capitalize and amortize the assets over its useful life.
Product Shipment Costs	Product Shipment Costs Product shipment costs, included in sales, marketing and administrative expense in the accompanying Consolidated Statements of Operations, were $25.4 million, $24.0 million, and $24.5 million for the years ended December 31, 2018, 2017, and 2016, respectively. The majority of the Company’s shipping costs are related to providing instrument sets for surgical procedures, which are not typically sold as part of the Company’s core sales offering. Amounts billed to customers for shipping and handling of products are reflected in revenues and are not material for any period presented.
Business Transition Costs	Business Transition Costs The Company incurs which include severance, relocation, consulting, leasehold exit costs, third-party merger and acquisition costs, contingent consideration fair value adjustments and other costs directly associated with such activities. The Company incurred $11.5 million of such costs during the year ended December 31, 2018 During the year ended December 31, 2017, the Company incurred $4.3 million of such costs, which consisted primarily of acquisition and integration activities, offset by $(1.3) million of fair value adjustments on contingent consideration liabilities associated with the Company’s 2017 and 2016 acquisitions. During the year ended December 31, 2016, the Company incurred $18.1 million of business transition costs, which consisted primarily of acquisition and integration activities, and $7.3 million of fair value adjustments on contingent consideration liabilities associated with the Company’s 2016 acquisitions.
Stock-based Compensation	Stock-based Compensation Stock-based compensation expense for equity-classified awards, principally related to restricted stock units (“RSUs”) and performance restricted stock units (“PRSUs”), is measured at the grant date based on the estimated fair value of the award. The fair value of equity instruments that are expected to vest is recognized and amortized over the requisite service period. The Company has granted awards with up to five year graded or cliff vesting terms . The fair value of RSUs including PRSUs with pre-defined performance criteria pre-defined performance criteria is adjusted with the probability of achievement of such performance criteria at each period end Stock-based compensation expense is adjusted from the grant date to exclude expense for awards that are expected to be forfeited. The forfeiture estimate is adjusted as necessary through the vesting date so that full compensation cost is recognized only for awards that vest. The Company assesses the reasonableness of the estimated forfeiture rate at least annually, with any change to be made on a cumulative basis in the period the estimated forfeiture rates change. The Company considered its historical experience of pre-vesting forfeitures on awards by each homogenous group of shareowners as the basis to arrive at its estimated annual pre-vesting forfeiture rates. The Company estimates the fair value of stock options issued under its equity incentive plans and shares issued to shareowners under its employee stock purchase plan (“ESPP”) using a Black-Scholes option-pricing model on the date of grant. The Black-Scholes option-pricing model incorporates various and highly sensitive assumptions including expected volatility, expected term and risk-free interest rates. The expected volatility is based on the historical volatility of the Company’s common stock over the most recent period commensurate with the estimated expected term of the Company’s stock options and ESPP offering period which is derived from historical experience. The risk-free interest rate for periods within the contractual life of the option is based on the U.S. Treasury yield in effect at the time of grant. The Company has never declared or paid dividends and has no plans to do so in the foreseeable future . See Note 7 to the Consolidated Financial Statements included in this Annual Report for further discussion on stockholder equity and stock-based compensation.
Net Income Per Share	Net Income Per Share The Company computes basic net income per share using the weighted-average number of common shares outstanding during the period. Diluted net income 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, unvested RSUs, including those with performance and market conditions, warrants, and the shares to be issued upon the conversion of the Senior Convertible Notes. The contingently issuable shares are included in basic net income per share as of the date that all necessary conditions have been satisfied and are included in the denominator for dilutive calculation for the entire period if such shares would be issuable as of the end of the reporting period assuming the end of the reporting period was the end of the contingency period. The following table sets forth the computation of basic and diluted earnings per share: Year Ended December 31, ( in thousands, except per share data 2018 2017 2016 Numerator: Net income attributable to NuVasive, Inc. $ 12,479 $ 81,598 $ 37,192 Denominator for basic and diluted net income per share: Weighted average common shares outstanding for basic 51,382 50,874 50,077 Dilutive potential common stock outstanding: Stock options and ESPP 36 141 314 RSUs 760 1,083 1,273 Warrants — 1,494 1,297 Senior Convertible Notes 177 1,601 1,141 Weighted average common shares outstanding for diluted 52,355 55,193 54,102 Basic net income per share attributable to NuVasive, Inc. $ 0.24 $ 1.60 $ 0.74 Diluted net income per share attributable to NuVasive, Inc. $ 0.24 $ 1.48 $ 0.69 The following weighted outstanding common stock equivalents were not included in the calculation of net income per diluted share because their effects were anti-dilutive: Year Ended December 31, ( in thousands 2018 2017 2016 Stock options, ESPP, and RSUs 162 147 912 Warrants 10,865 10,865 13,253 Senior Convertible Notes 5,433 2,716 7,550 Total 16,460 13,728 21,715

Organization and Significant _3

Organization and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Impacts of ASC 606 Adoption on the Company's Previously Filed Unaudited Consolidated Financial Statements	The following tables summarize in a condensed presentation the impact of the adoption of ASC 606 on the Company’s previously reported Consolidated Balance Sheet as of December 31, 2017, the Consolidated Statements of Operations and Comprehensive Income for the years ended December 31, 2017 and 2016, and the Consolidated Statements of Cash Flows for the years ended December 31, 2017 and 2016. NUVASIVE, INC. CONSOLIDATED BALANCE SHEET (in thousands) As of December 31, 2017 As reported Adjustments As Adjusted Accounts receivable, gross $ 212,709 $ 537 [a] $ 213,246 Allowances on accounts receivable (13,669 ) 643 [b] (13,026 ) Inventory, net 247,245 (107 ) [c] 247,138 Other current assets 112,705 — 112,705 Total current assets 558,990 1,073 560,063 Remaining other assets 1,080,077 — 1,080,077 Total assets $ 1,639,067 $ 1,073 $ 1,640,140 Accounts payable and accrued liabilities 75,076 691 [d] 75,767 Accrued payroll and related expenses 55,582 36 [e] 55,618 Other current liabilities 30,010 — 30,010 Total current liabilities 160,668 727 161,395 Deferred and income tax liabilities, non-current 18,786 84 [f] 18,870 Other long-term liabilities 660,459 — 660,459 Total NuVasive, Inc. stockholders’ equity 795,309 262 [g] 795,571 Non-controlling interests 3,845 — 3,845 Total equity 799,154 262 799,416 Total liabilities and equity $ 1,639,067 $ 1,073 $ 1,640,140 [a] Represents cumulative impact from January 1, 2016 to the period presented on accounts receivable for the full retrospective method of adoption of ASC 606. [b] Represents cumulative impact from January 1, 2016 to the period presented on allowances on accounts receivable for the full retrospective method of adoption of ASC 606. [c] Represents cumulative impact from January 1, 2016 to the period presented on inventory for the full retrospective method of adoption of ASC 606. [d] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable and accrued returns for the full retrospective method of adoption of ASC 606. [e] Represents cumulative impact from January 1, 2016 to the period presented on commissions payable for the full retrospective method of adoption of ASC 606. [f] Represents cumulative impact from January 1, 2016 to the period presented on deferred tax liabilities for the full retrospective method of adoption of ASC 606. [g] Represents cumulative impact from January 1, 2016 to the period presented on retained earnings for the full retrospective method of adoption of ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands, except per share amounts) Year ended December 31, 2017 As reported Adjustments As adjusted Revenue Product revenue $ 941,816 $ (2,835 ) [a] $ 938,981 Service revenue 87,704 — 87,704 Total revenue 1,029,520 (2,835 ) 1,026,685 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 207,874 (567 ) [b] 207,307 Cost of services 61,134 — 61,134 Total cost of revenue 269,008 (567 ) 268,441 Gross profit 760,512 (2,268 ) 758,244 Operating expenses: Sales, marketing and administrative 539,913 (406 ) [c] 539,507 Other operating expenses 107,251 — 107,251 Total operating expenses 647,164 (406 ) 646,758 Total interest and other expense, net (39,123 ) — (39,123 ) Income tax benefit 7,038 454 [d] 7,492 Consolidated net income $ 81,263 $ (1,408 ) [e] $ 79,855 Add back net loss attributable to non-controlling interests $ (1,743 ) $ — $ (1,743 ) Net income attributable to NuVasive, Inc. $ 83,006 $ (1,408 ) [e] $ 81,598 Net income per share attributable to NuVasive, Inc.: Basic $ 1.63 $ (0.03 ) [f] $ 1.60 Diluted $ 1.50 $ (0.02 ) [f] $ 1.48 Comprehensive income attributable to NuVasive, Inc. $ 86,704 $ (1,408 ) [e] $ 85,296 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Revenue Product revenue $ 893,484 $ 60 [a] $ 893,544 Service revenue 68,588 — 68,588 Total revenue 962,072 60 962,132 Cost of revenue (excluding amortization of intangible assets) Cost of products sold 195,593 12 [b] 195,605 Cost of services 44,500 — 44,500 Total cost of revenue 240,093 12 240,105 Gross profit 721,979 48 722,027 Operating expenses: Sales, marketing and administrative 533,624 (24 ) [c] 533,600 Other operating expenses 64,828 — 64,828 Total operating expenses 598,452 (24 ) 598,428 Total interest and other expense, net (58,819 ) — (58,819 ) Income tax expense (29,282 ) (27 ) [d] (29,309 ) Consolidated net income $ 35,426 $ 45 [e] $ 35,471 Add back net loss attributable to non-controlling interests $ (1,721 ) $ — $ (1,721 ) Net income attributable to NuVasive, Inc. $ 37,147 $ 45 [e] $ 37,192 Net income per share attributable to NuVasive, Inc.: Basic $ 0.74 $ 0.00 [f] $ 0.74 Diluted $ 0.69 $ 0.00 [f] $ 0.69 Comprehensive income attributable to NuVasive, Inc. $ 38,628 $ 45 [e] $ 38,673 [a] Represents net change in sales revenue for charge sheet orders recognized under ASC 606. [b] Represents net change in cost of products sold for charge sheet orders recognized under ASC 606. [c] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. [d] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [e] Represents change in net income and comprehensive income resulting from net change in charge sheet orders recognized under ASC 606. [f] Represents earnings per share impact resulting from net change in charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2017 As reported Adjustments As adjusted Consolidated net income $ 81,263 $ (1,408 ) [a] $ 79,855 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 5,718 (96 ) [b] 5,622 Deferred income tax benefit (12,384 ) (454 ) [c] (12,838 ) Other adjustments to reconcile net income 180,666 — 180,666 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (29,389 ) 2,779 [d] (26,610 ) Inventory (35,300 ) (567 ) [e] (35,867 ) Prepaid expenses and other current assets (12,681 ) [f] — (12,681 ) Accounts payable and accrued liabilities (16,617 ) (141 ) [g] (16,758 ) Litigation liability 8,150 — 8,150 Accrued payroll and related expenses 4,088 (113 ) [g] 3,975 Income taxes 3,455 — 3,455 Net cash provided by operating activities 176,969 — 176,969 Net cash used in investing activities (174,861 ) — (174,861 ) Net cash used in financing activities (87,028 ) — (87,028 ) Effect of exchange rate changes on cash 2,070 — 2,070 Decrease in cash, cash equivalents and restricted cash $ (82,850 ) $ — $ (82,850 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606. NUVASIVE, INC. CONSOLIDATED STATEMENT OF CASH FLOWS (in thousands) Year ended December 31, 2016 As reported Adjustments As adjusted Consolidated net income $ 35,426 $ 45 [a] $ 35,471 Adjustments to reconcile net income to net cash provided by operating activities: Reserves on current assets 11,408 44 [b] 11,452 Deferred income tax expense 26,265 27 [c] 26,292 Other adjustments to reconcile net income 188,371 — 188,371 Changes in operating assets and liabilities, net of effects from acquisitions: Accounts receivable (33,250 ) (171 ) [d] (33,421 ) Inventory (22,636 ) 12 [e] (22,624 ) Prepaid expenses and other current assets (3,875 ) [f] — (3,875 ) Accounts payable and accrued liabilities 12,325 51 [g] 12,376 Litigation liability (88,450 ) — (88,450 ) Accrued payroll and related expenses 8,849 (8 ) [g] 8,841 Income taxes 23,652 — 23,652 Net cash provided by operating activities 158,085 — 158,085 Net cash used in investing activities (304,885 ) — (304,885 ) Net cash provided by financing activities 110,823 — 110,823 Effect of exchange rate changes on cash (929 ) — (929 ) Decrease in cash, cash equivalents and restricted cash $ (36,906 ) $ — $ (36,906 ) [a] Represents change in net income resulting from charge sheet orders recognized under ASC 606. [b] Represents net change in allowances on accounts receivable for charge sheet orders recognized under ASC 606. [c] Represents deferred income tax liability on net change associated with charge sheet orders recognized under ASC 606. [d] Represents net change in accounts receivable for charge sheet orders recognized under ASC 606. [e] Represents net change in inventory for charge sheet orders recognized under ASC 606. [f] Recasted for adoption of ASU 2016-18 to exclude the impact of transfers to/from restricted cash balances. [g] Represents net change in accrued sales commissions for charge sheet orders recognized under ASC 606.
Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share: Year Ended December 31, ( in thousands, except per share data 2018 2017 2016 Numerator: Net income attributable to NuVasive, Inc. $ 12,479 $ 81,598 $ 37,192 Denominator for basic and diluted net income per share: Weighted average common shares outstanding for basic 51,382 50,874 50,077 Dilutive potential common stock outstanding: Stock options and ESPP 36 141 314 RSUs 760 1,083 1,273 Warrants — 1,494 1,297 Senior Convertible Notes 177 1,601 1,141 Weighted average common shares outstanding for diluted 52,355 55,193 54,102 Basic net income per share attributable to NuVasive, Inc. $ 0.24 $ 1.60 $ 0.74 Diluted net income per share attributable to NuVasive, Inc. $ 0.24 $ 1.48 $ 0.69
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 per diluted share because their effects were anti-dilutive: Year Ended December 31, ( in thousands 2018 2017 2016 Stock options, ESPP, and RSUs 162 147 912 Warrants 10,865 10,865 13,253 Senior Convertible Notes 5,433 2,716 7,550 Total 16,460 13,728 21,715

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2018
Balance Sheet Details [Abstract]
Property and Equipment Net	Property and Equipment, net Property and equipment, net, consisted of the following: December 31, ( in thousands, except years Useful Life 2018 2017 Instrument sets 4 $ 326,831 $ 287,435 Machinery and equipment 5 to 7 58,585 49,142 Computer equipment and software 3 to 7 127,539 102,729 Leasehold improvements 2 to 15 32,973 23,532 Furniture and fixtures 3 to 7 8,961 8,311 Building and improvements 10 to 20 20,216 20,146 Land — 1,277 1,277 576,382 492,572 Less: accumulated depreciation and amortization (337,541 ) (277,246 ) $ 238,841 $ 215,326
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill and intangible assets as of December 31, 2018 consisted of the following: Weighted- Average Amortization Period Gross Accumulated Intangible ( in thousands, except years (in years) Amount Amortization Assets, net Intangible assets subject to amortization: Developed technology 8 $ 271,748 $ (131,730 ) $ 140,018 Manufacturing know-how and trade secrets 13 30,814 (17,926 ) 12,888 Trade name and trademarks 9 25,500 (13,901 ) 11,599 Customer relationships 9 147,021 (59,478 ) 87,543 Total intangible assets subject to amortization 9 $ 475,083 $ (223,035 ) $ 252,048 Intangible assets not subject to amortization: Goodwill 561,366 Total goodwill and intangible assets, net $ 813,414 Goodwill and intangible assets as of December 31, 2017 consisted of the following: Weighted- Average Amortization Period Gross Accumulated Intangible ( in thousands, except years (in years) Amount Amortization Assets, net Intangible assets subject to amortization: Developed technology 8 $ 271,748 $ (98,693 ) $ 173,055 Manufacturing know-how and trade secrets 13 30,653 (15,542 ) 15,111 Trade name and trademarks 9 25,200 (10,559 ) 14,641 Customer relationships 9 122,249 (44,282 ) 77,967 Total intangible assets subject to amortization 9 $ 449,850 $ (169,076 ) $ 280,774 Intangible assets not subject to amortization: Goodwill 536,926 Total goodwill and intangible assets, net $ 817,700
Changes to Goodwill	The changes to goodwill are comprised of the following: ( in thousands December 31, 2017 Gross goodwill $ 545,226 Accumulated impairment loss (8,300 ) 536,926 Changes to gross goodwill Increases recorded in business combinations 26,959 Changes in purchase price allocation (1,075 ) Changes resulting from foreign currency fluctuations (1,444 ) 24,440 December 31, 2018 Gross goodwill 569,666 Accumulated impairment loss (8,300 ) $ 561,366
Future Amortization Expense Related to Intangible Assets	Total future amortization expense related to intangible assets subject to amortization at December 31, 2018 is set forth in the table below: ( in thousands 2019 $ 52,298 2020 51,675 2021 49,297 2022 41,834 2023 17,718 Thereafter through 2031 39,226 Total future amortization expense $ 252,048
Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities consisted of the following: December 31, ( in thousands 2018 2017 Accrued expenses $ 70,386 $ 42,983 Other taxes payable 9,359 12,692 Accounts payable 8,799 4,366 Distributor commissions payable 8,194 7,697 Royalties payable 7,173 5,040 Other 1,966 2,989 Accounts payable and accrued liabilities $ 105,877 $ 75,767

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	Cash equivalents are determined under the fair value categories as follows: Quoted Price in Significant Other Significant Active Market Observable Inputs Unobservable ( in thousands Total (Level 1) (Level 2) Inputs (Level 3) December 31, 2018 Cash equivalents: Money market funds $ 56,000 $ 56,000 $ — $ — Total cash equivalents $ 56,000 $ 56,000 $ — $ — December 31, 2017 Cash equivalents: Money market funds $ 27,000 $ 27,000 $ — $ — Total cash equivalents $ 27,000 $ 27,000 $ — $ —
Schedule of Fair Value of Liabilities Measured on Recurring Basis Using Unobservable Inputs	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 2018 2017 Fair value measurement at January 1 $ 67,941 $ 67,501 Contingent consideration liability recorded upon acquisition 3,543 32,559 Change in fair value measurement (1,517 ) (1,295 ) Changes resulting from foreign currency fluctuations 193 (224 ) Contingent consideration paid or settled (19,750 ) (30,600 ) Fair value measurement at December 31 $ 50,410 $ 67,941

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combination Description [Abstract]
Reconciliation of equity attributable to the non-controlling interests	The following is a reconciliation of equity (net assets) attributable to the non-controlling interest: Year Ended December 31, ( in thousands 2018 2017 Non-controlling interests at beginning of period $ 3,845 $ 5,588 Acquired non-controlling interest reclassified to additional paid-in capital (3,845 ) — Less: net loss attributable to the non-controlling interests — (1,743 ) Non-controlling interests at end of period $ — $ 3,845
Summary of assets and liabilities included in the accompanying consolidated balance sheet	Total assets and liabilities of Progentix as a VIE included in the accompanying Consolidated Balance Sheets are as follows: December 31, ( in thousands 2018 2017 Total current assets $ — $ 670 Identifiable intangible assets, net — 8,752 Goodwill — 12,654 Accounts payable & accrued expenses — 562 Deferred tax liabilities, net — 331 Non-controlling interests — 3,845

Indebtedness (Tables)

Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Carrying Value of Senior Convertible Notes	The carrying values of the Company’s Senior Convertible Notes due 2021 are as follows: ( in thousands December 31, 2018 December 31, 2017 2.25% Senior Convertible Notes due 2021: Principal amount $ 650,000 $ 650,000 Unamortized debt discount (40,117 ) (56,839 ) Unamortized debt issuance costs (7,357 ) (10,241 ) Total Senior Convertible Notes $ 602,526 $ 582,920

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Annual Lease Payments under Capital and Operating Leases	The Company’s future minimum annual lease payments under capital and operating leases, including payments for costs directly associated with the facility leases, for years ending after December 31, 2018 are as follows: Capital Operating ( in thousands Leases Leases 2019 $ 534 $ 13,750 2020 507 13,007 2021 244 10,954 2022 24 10,578 2023 5 10,515 Thereafter — 116,684 Total minimum lease payments $ 1,314 $ 175,488 Less amount representing interest (59 ) Present value of obligations under capital leases 1,255 Less current portion (449 ) Long-term capital lease obligations $ 806

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Compensation Costs Included in Consolidated Statement of Operations for All Stock-based Compensation Arrangements	The compensation cost that has been included in the Consolidated Statements of Operations for the Company’s stock-based compensation plans was as follows: Year Ended December 31, ( in thousands 2018 2017 2016 Sales, marketing and administrative expense $ 22,190 $ 20,596 $ 25,466 Research and development expense 3,052 1,445 1,231 Cost of goods sold 431 350 227 Stock-based compensation expense before taxes 25,673 22,391 26,924 Related income tax benefits (6,418 ) (8,509 ) (10,770 ) Stock-based compensation expense, net of taxes $ 19,255 $ 13,882 $ 16,154
Summary of Restricted Stock Units	Following is a summary of RSU activity for the year ended December 31, 2018: Weighted Average Number of Grant Date ( in thousands, except per share amounts Shares Fair Value Outstanding at December 31, 2017 996 $ 52.90 Granted 467 55.55 Vested (169 ) 42.94 Forfeited (180 ) 55.63 Outstanding at December 31, 2018 1,114 $ 55.25
Schedule of Performance-Based Restricted Stock Units	Following is a summary of PRSU activity for the year ended December 31, 2018: Maximum Number ( in thousands, except per share amounts Shares of Shares Eligible to be Issued Average Grant Date Fair Value Outstanding at December 31, 2017 765 1,462 $ 52.62 Awarded at target 369 479 54.86 Vested (21 ) (21 ) 48.73 Forfeited (126 ) (262 ) 55.39 Outstanding at December 31, 2018 987 1,658 $ 56.88
Summary of Stock Option Activity under All Stock Plans	Following is a summary of stock option activity for the year ended December 31, 2018 under all stock plans: Weighted-Average Remaining Weighted Contractual Aggregate Avg. Exercise Term Intrinsic ( in thousands, except years and per share amounts Shares Price (Years) Value Outstanding at December 31, 2017 178 $ 35.41 1.33 $ 4,105 Exercised (128 ) 35.28 Cancelled (1 ) 34.49 Outstanding at December 31, 2018 49 35.76 1.52 $ 680 Exercisable at December 31, 2018 49 $ 35.76 1.52 $ 680 Vested or expected to vest at December 31, 2018 49 $ 35.76 1.52 $ 680
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 options granted and stock purchase rights under the ESPP are as follows: Year Ended December 31, 2018 2017 2016 ESPP Volatility 33 % 26 % 29 % Expected term (years) 0.5 0.5 0.5 Risk free interest rate 1.8 % 0.9 % 0.4 % Expected dividend yield — % — % — %
Common Stock Reserved for Future Issuance	Common Stock Reserved for Future Issuance The following table summarizes common shares reserved for issuance on exercise or conversion at December 31, 2018 ( in thousands Issued and outstanding stock options 49 Issued and outstanding RSUs and PRSUs 2,183 Available for issuance under the ESPP 1,093 Available for future grant 3,752 2021 Notes 14,396 2021 Warrants 32,596 Total shares reserved for future issuance 54,069

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Summary of Income Before Income Taxes By Region	Total income before income taxes summarized by region for the years ended December 31 is as follows: Year Ended December 31, ( in thousands 2018 2017 2016 United States $ 8,939 $ 76,480 $ 77,610 Foreign (216 ) (4,117 ) (12,830 ) Total income before income taxes $ 8,723 $ 72,363 $ 64,780
Components of Income Tax (Benefit) Provision	The income tax (benefit) provision for the years ended December 31 consists of the following: Year Ended December 31, ( in thousands 2018 2017 2016 Current: Federal $ (4,188 ) $ 5,972 $ (14,837 ) State 2,043 776 1,283 Foreign 5,972 2,793 2,350 Total current provision 3,827 9,541 (11,204 ) Deferred: Federal (5,944 ) (1,565 ) 40,363 State (7,092 ) (4,276 ) 1,455 Foreign (98,795 ) (2,223 ) (2,583 ) Total deferred provision (111,831 ) (8,064 ) 39,235 Changes in tax rate 258 (14,668 ) (216 ) Changes in valuation allowance 103,990 5,699 1,494 Total (benefit) provision $ (3,756 ) $ (7,492 ) $ 29,309
Reconciliation of Income Tax from Statutory Tax Rate to Effective Income Tax Rate	The differences between the income tax provision at the United States federal statutory tax rate and the Company’s effective tax rate for the years ended December 31 are the following: Year Ended December 31, ( in thousands 2018 2017 2016 Tax provision at federal statutory rate $ 1,832 $ 25,327 $ 22,673 Valuation allowance 103,990 5,703 1,494 Net tax benefit on international restructuring (97,028 ) — — Income tax reserves (6,717 ) 1,184 759 Income tax credits and incentives (5,525 ) (3,462 ) (3,426 ) Return to provision adjustments (4,180 ) (2,443 ) (1,188 ) Compensation expense 2,008 (5,619 ) (8,013 ) Globalization initiative 1,264 306 6,290 Nondeductible meals and entertainment 769 922 1,013 Foreign tax rate differences from federal statutory rate (688 ) 378 605 Change in tax rates 258 (14,668 ) (216 ) Acquisition related charges (221 ) (489 ) 5,167 State income tax 90 3,553 3,245 Recovery of tax basis in United States subsidiary — (19,540 ) — Other 392 1,356 906 Total (benefit) provision $ (3,756 ) $ (7,492 ) $ 29,309
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities at December 31 are composed of the following: December 31, ( in thousands 2018 2017 Deferred tax assets: Amortization $ 106,769 $ 6,742 General business and other credit carryforwards 25,846 18,928 Stock-based compensation 14,914 13,502 Inventory 12,385 10,075 Net operating loss carryforwards 7,516 14,991 Deferred rent 4,628 2,532 Original issue discount 3,322 4,606 Other 23,241 14,859 Gross deferred tax assets 198,621 86,235 Less valuation allowance (120,233 ) (16,247 ) Net deferred tax assets 78,388 69,988 Deferred tax liabilities: Acquired intangibles (42,767 ) (53,076 ) Depreciation (32,851 ) (23,132 ) Other (1,843 ) (1,752 ) Total deferred tax liabilities (77,461 ) (77,960 ) Consolidated net deferred tax assets (liabilities) $ 927 $ (7,972 ) Add deferred tax liability, net, attributable to non-controlling interests — 199 Net deferred tax assets (liabilities) $ 927 $ (7,773 )
Summary of Unrecognized Tax Benefits	The following table summarizes the activity related to the Company’s unrecognized tax benefits: Year Ended December 31, ( in thousands 2018 2017 2016 Gross unrecognized tax benefits at January 1 $ 25,356 $ 23,322 $ 12,448 Increases in tax positions for prior years 499 1,692 1,716 Decreases in tax positions for prior years (756 ) (24 ) (270 ) Increases in tax positions for current year relating to ongoing operations 1,913 968 6,205 Decreases in tax positions as a result of a lapse of statute of limitations (6,446 ) (402 ) — Increases in tax positions for current year relating to acquisitions 169 — 3,223 Decreases in tax positions due to settlements with taxing authorities (1,190 ) (200 ) — Gross unrecognized tax benefits at December 31 $ 19,545 $ 25,356 $ 23,322

Business Segment, Product and G

Business Segment, Product and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Revenue by Product Lines	Revenue by product line was as follows: Year Ended December 31, ( in thousands 2018 2017 2016 Spinal Hardware $ 788,650 $ 737,534 $ 683,703 Surgical Support 313,064 289,151 278,429 Total Revenue $ 1,101,714 $ 1,026,685 $ 962,132
Schedule of Revenue and Net Property and Equipment by Geographical Area	Revenue and property and equipment, net, by geographic area were as follows: Revenue Property Year Ended December 31, December 31, ( in thousands 2018 2017 2016 2018 2017 United States $ 896,152 $ 850,410 $ 831,778 $ 200,404 $ 179,891 International (excludes Puerto Rico) 205,562 176,275 130,354 38,437 35,435 Total $ 1,101,714 $ 1,026,685 $ 962,132 $ 238,841 $ 215,326

Quarterly Data (unaudited) (Tab

Quarterly Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of unaudited quarterly financial data	The following quarterly financial data, in the opinion of management, reflects all adjustments, consisting of normal recurring adjustments necessary, for a fair presentation of results for the periods presented: Year Ended December 31, 2018 (1) (2) (3) ( in thousands, except per share amounts First Quarter Second Quarter Third Quarter Fourth Quarter Revenue $ 260,522 $ 281,564 $ 271,301 $ 288,327 Gross profit 186,708 204,508 197,141 202,198 Consolidated net (loss) income (27,132 ) 11,531 15,923 12,157 Basic net (loss) income per common (0.53 ) 0.22 0.31 0.24 Diluted net (loss) income per common share (0.53 ) 0.22 0.30 0.23 Year Ended December 31, 2017 (4) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue $ 249,013 $ 259,399 $ 247,051 $ 271,222 Gross profit 187,570 193,213 181,544 195,917 Consolidated net income 11,983 11,735 33,096 23,041 Net income attributable to NuVasive, Inc. 12,426 12,167 33,528 23,477 Basic net income per common share attributable to NuVasive, Inc. 0.25 0.24 0.66 0.46 Diluted net income per common share attributable to NuVasive, Inc. 0.22 0.21 0.64 0.45 (1) The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion. (2) The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion. (3) Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc (4) The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Organization and Significant _4

Organization and Significant Accounting Policies (Details Textual)	Oct. 01, 2018USD ($)	Dec. 31, 2018USD ($)Customersegment	Dec. 31, 2017USD ($)Customer$ / shares	Dec. 31, 2016USD ($)Customer	Dec. 31, 2015USD ($)	Jan. 01, 2019USD ($)	Jan. 01, 2017USD ($)
Schedule Of Organization And Significant Accounting Policies [Line Items]
Cumulative effect of change on retained earnings		$ 17,241,000	$ 4,762,000
Adjustment to accumulated deficit					$ 1,625,000
Customer represented greater than 10 percent | Customer		0	0	0
Inventory, finished goods		$ 259,400,000	$ 232,300,000
Inventory, raw materials		8,800,000	5,000,000
Inventory, work in progress		$ 5,000,000	$ 9,800,000
Number of Reportable Units | segment		1
Impairment of goodwill and intangible assets	$ 0
Impairment charges related to goodwill		$ 0
Tax cuts and jobs act 2017, executive compensation related deferred taxes and federal tax revaluation impact write-down		300,000
Tax cuts and jobs act 2017, increase in effective income tax rate due to deferred tax and federal tax revaluation impact write-down			0.50%
Translation Adjustment Functional to Reporting Currency, Net of Tax		8,600,000	$ 6,900,000	$ 10,600,000
Product shipment costs		311,159,000	268,441,000	240,105,000
Business transition costs		$ 11,473,000	4,287,000	18,138,000
Performance-Based Restricted Stock Units (PRSUs) [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Vesting period for the award		5 years			5 years
New Jersey [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Business transition costs				7,300,000
2017 and 2016 Acquisitions [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Business transition costs		$ (1,500,000)	(1,300,000)
Product Shipment [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Product shipment costs		$ 25,400,000	24,000,000	24,500,000
Minimum [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Finite-Lived intangible assets, useful life		1 year
Property and equipment, useful life		2 years
Maximum [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Finite-Lived intangible assets, useful life		17 years
Property and equipment, useful life		20 years
ASU 2016-02 [Member] | Subsequent Event [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Right-of-use assets						$ 62,000,000
Right-of-use liabilities						$ 75,000,000
Accounting Standards Update 2014-09 [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Product shipment costs			268,441,000	240,105,000
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Cumulative effect of change on retained earnings			300,000
Product shipment costs			(567,000)	12,000
Accounting Standards Update 2014-09 [Member] | Retained Earnings (Accumulated Deficit) [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Adjustment to accumulated deficit				$ 1,600
ASU 2016-16 [Member] | Adjustments for New Accounting Principle, Early Adoption [Member]
Schedule Of Organization And Significant Accounting Policies [Line Items]
Retrospective adjustment to deferred tax assets and accumulated deficit							$ 11,600,000
Decrease in Income tax expense			$ (3,900,000)
Increase in basic earnings per share | $ / shares			$ 0.08
Increase in diluted earnings per share | $ / shares			$ 0.07

Organization and Significant _5

Organization and Significant Accounting Policies - Summary of Condensed Presentation Impact of Adoption of ASC 606 Adoption on the Company's Previously Reported Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowances on accounts receivable	$ (16,171)	$ (13,026)
Inventory, net	273,244	247,138
Total current assets	618,209	560,063
Other assets	29,737	39,117
Total assets	1,707,859	1,640,140
Accounts payable and accrued liabilities	105,877	75,767
Accrued payroll and related expenses	59,960	55,618
Total current liabilities	179,460	161,395
Deferred and income tax liabilities, non-current	4,964	18,870
Other long-term liabilities	86,384	77,539
Total NuVasive, Inc. stockholders’ equity	834,525	795,571
Non-controlling interests		3,845
Total equity	834,525	799,416
Total liabilities and equity	$ 1,707,859	1,640,140
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, gross		213,246
Allowances on accounts receivable		(13,026)
Inventory, net		247,138
Other current assets		112,705
Total current assets		560,063
Other assets		1,080,077
Total assets		1,640,140
Accounts payable and accrued liabilities		75,767
Accrued payroll and related expenses		55,618
Other current liabilities		30,010
Total current liabilities		161,395
Deferred and income tax liabilities, non-current		18,870
Other long-term liabilities		660,459
Total NuVasive, Inc. stockholders’ equity		795,571
Non-controlling interests		3,845
Total equity		799,416
Total liabilities and equity		1,640,140
Accounting Standards Update 2014-09 [Member] | As Reported [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, gross		212,709
Allowances on accounts receivable		(13,669)
Inventory, net		247,245
Other current assets		112,705
Total current assets		558,990
Other assets		1,080,077
Total assets		1,639,067
Accounts payable and accrued liabilities		75,076
Accrued payroll and related expenses		55,582
Other current liabilities		30,010
Total current liabilities		160,668
Deferred and income tax liabilities, non-current		18,786
Other long-term liabilities		660,459
Total NuVasive, Inc. stockholders’ equity		795,309
Non-controlling interests		3,845
Total equity		799,154
Total liabilities and equity		1,639,067
Accounting Standards Update 2014-09 [Member] | Adjustments [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, gross		537
Allowances on accounts receivable		643
Inventory, net		(107)
Total current assets		1,073
Total assets		1,073
Accounts payable and accrued liabilities		691
Accrued payroll and related expenses		36
Total current liabilities		727
Deferred and income tax liabilities, non-current		84
Total NuVasive, Inc. stockholders’ equity		262
Total equity		262
Total liabilities and equity		$ 1,073

Organization and Significant _6

Organization and Significant Accounting Policies - Summary of Condensed Presentation Impact of Adoption of ASC 606 on the Company's Previously Reported Unaudited Consolidated Statement of Operations and Comprehensive Income (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1],[2],[3]	Sep. 30, 2018	[1],[2],[3]	Jun. 30, 2018	[1],[2],[3]	Mar. 31, 2018	[1],[2],[3]	Dec. 31, 2017	[4]	Sep. 30, 2017	[4]	Jun. 30, 2017	[4]	Mar. 31, 2017	[4]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Total revenue	$ 288,327		$ 271,301		$ 281,564		$ 260,522		$ 271,222		$ 247,051		$ 259,399		$ 249,013		$ 1,101,714	$ 1,026,685	$ 962,132
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																	311,159	268,441	240,105
Gross profit	202,198		197,141		204,508		186,708		195,917		181,544		193,213		187,570		790,555	758,244	722,027
Operating expenses:
Sales, marketing and administrative																	575,836	539,507	533,600
Total operating expenses																	736,387	646,758	598,428
Total interest and other expense, net																	(45,445)	(39,123)	(58,819)
Income tax benefit																	3,756	7,492	(29,309)
Consolidated net income	$ 12,157		$ 15,923		$ 11,531		$ (27,132)		23,041		33,096		11,735		11,983		12,479	79,855	35,471
Add back net loss attributable to non-controlling interests																		(1,743)	(1,721)
Net income attributable to NuVasive, Inc.									$ 23,477		$ 33,528		$ 12,167		$ 12,426		$ 12,479	$ 81,598	$ 37,192
Net income per share attributable to NuVasive, Inc.:
Basic	$ 0.24		$ 0.31		$ 0.22		$ (0.53)		$ 0.46		$ 0.66		$ 0.24		$ 0.25		$ 0.24	$ 1.60	$ 0.74
Diluted	$ 0.23		$ 0.30		$ 0.22		$ (0.53)		$ 0.45		$ 0.64		$ 0.21		$ 0.22		$ 0.24	$ 1.48	$ 0.69
Comprehensive income attributable to NuVasive, Inc.																	$ 10,784	$ 85,296	$ 38,673
Product [Member]
Revenue
Total revenue																	986,458	938,981	893,544
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																	234,509	207,307	195,605
Service [Member]
Revenue
Total revenue																	115,256	87,704	68,588
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																	$ 76,650	61,134	44,500
Accounting Standards Update 2014-09 [Member]
Revenue
Total revenue																		1,026,685	962,132
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		268,441	240,105
Gross profit																		758,244	722,027
Operating expenses:
Sales, marketing and administrative																		539,507	533,600
Other operating expenses																		107,251	64,828
Total operating expenses																		646,758	598,428
Total interest and other expense, net																		(39,123)	(58,819)
Income tax benefit																		7,492	(29,309)
Consolidated net income																		79,855	35,471
Add back net loss attributable to non-controlling interests																		(1,743)	(1,721)
Net income attributable to NuVasive, Inc.																		$ 81,598	$ 37,192
Net income per share attributable to NuVasive, Inc.:
Basic																		$ 1.60	$ 0.74
Diluted																		$ 1.48	$ 0.69
Comprehensive income attributable to NuVasive, Inc.																		$ 85,296	$ 38,673
Accounting Standards Update 2014-09 [Member] | As Reported [Member]
Revenue
Total revenue																		1,029,520	962,072
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		269,008	240,093
Gross profit																		760,512	721,979
Operating expenses:
Sales, marketing and administrative																		539,913	533,624
Other operating expenses																		107,251	64,828
Total operating expenses																		647,164	598,452
Total interest and other expense, net																		(39,123)	(58,819)
Income tax benefit																		7,038	(29,282)
Consolidated net income																		81,263	35,426
Add back net loss attributable to non-controlling interests																		(1,743)	(1,721)
Net income attributable to NuVasive, Inc.																		$ 83,006	$ 37,147
Net income per share attributable to NuVasive, Inc.:
Basic																		$ 1.63	$ 0.74
Diluted																		$ 1.50	$ 0.69
Comprehensive income attributable to NuVasive, Inc.																		$ 86,704	$ 38,628
Accounting Standards Update 2014-09 [Member] | Adjustments [Member]
Revenue
Total revenue																		(2,835)	60
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		(567)	12
Gross profit																		(2,268)	48
Operating expenses:
Sales, marketing and administrative																		(406)	(24)
Total operating expenses																		(406)	(24)
Income tax benefit																		454	(27)
Consolidated net income																		(1,408)	45
Net income attributable to NuVasive, Inc.																		$ (1,408)	$ 45
Net income per share attributable to NuVasive, Inc.:
Basic																		$ (0.03)	$ 0
Diluted																		$ (0.02)	$ 0
Comprehensive income attributable to NuVasive, Inc.																		$ (1,408)	$ 45
Accounting Standards Update 2014-09 [Member] | Product [Member]
Revenue
Total revenue																		938,981	893,544
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		207,307	195,605
Accounting Standards Update 2014-09 [Member] | Product [Member] | As Reported [Member]
Revenue
Total revenue																		941,816	893,484
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		207,874	195,593
Accounting Standards Update 2014-09 [Member] | Product [Member] | Adjustments [Member]
Revenue
Total revenue																		(2,835)	60
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		(567)	12
Accounting Standards Update 2014-09 [Member] | Service [Member]
Revenue
Total revenue																		87,704	68,588
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		61,134	44,500
Accounting Standards Update 2014-09 [Member] | Service [Member] | As Reported [Member]
Revenue
Total revenue																		87,704	68,588
Cost of revenue (excluding below amortization of intangible assets)
Total cost of revenue																		$ 61,134	$ 44,500
[1]	Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.
[2]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[3]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[4]	The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Organization and Significant _7

Organization and Significant Accounting Policies - Summary of Condensed Presentation Impact of Adoption of ASC 606 Adoption on the Company's Previously Reported Unaudited Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1],[2],[3]	Sep. 30, 2018	[1],[2],[3]	Jun. 30, 2018	[1],[2],[3]	Mar. 31, 2018	[1],[2],[3]	Dec. 31, 2017	[4]	Sep. 30, 2017	[4]	Jun. 30, 2017	[4]	Mar. 31, 2017	[4]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Consolidated net (loss) income	$ 12,157		$ 15,923		$ 11,531		$ (27,132)		$ 23,041		$ 33,096		$ 11,735		$ 11,983		$ 12,479	$ 79,855	$ 35,471
Adjustments to reconcile net income to net cash provided by operating activities:
Reserves on current assets																	14,834	5,622	11,452
Deferred income tax (benefit) expense																	(11,396)	(12,838)	26,292
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable																	4,562	(26,610)	(33,421)
Inventory																	(38,646)	(35,867)	(22,624)
Prepaid expenses and other current assets																	(1,280)	(12,681)	(3,875)
Accounts payable and accrued liabilities																	20,518	(5,558)	12,376
Litigation liability																	1,165	8,150	(88,450)
Accrued payroll and related expenses																	2,595	3,975	8,841
Income taxes																	2,054	3,455	23,652
Net cash provided by operating activities																	219,183	176,969	158,085
Net cash used in investing activities																	(161,285)	(174,861)	(304,885)
Net cash used in financing activities																	(14,578)	(87,028)	110,823
Effect of exchange rate changes on cash																	$ (1,283)	2,070	(929)
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Consolidated net (loss) income																		79,855	35,471
Adjustments to reconcile net income to net cash provided by operating activities:
Reserves on current assets																		5,622	11,452
Deferred income tax (benefit) expense																		(12,838)	26,292
Other adjustments to reconcile net income																		180,666	188,371
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable																		(26,610)	(33,421)
Inventory																		(35,867)	(22,624)
Prepaid expenses and other current assets																		(12,681)	(3,875)
Accounts payable and accrued liabilities																		(16,758)	12,376
Litigation liability																		8,150	(88,450)
Accrued payroll and related expenses																		3,975	8,841
Income taxes																		3,455	23,652
Net cash provided by operating activities																		176,969	158,085
Net cash used in investing activities																		(174,861)	(304,885)
Net cash used in financing activities																		(87,028)	110,823
Effect of exchange rate changes on cash																		2,070	(929)
Decrease in cash, cash equivalents and restricted cash																		(82,850)	(36,906)
Accounting Standards Update 2014-09 [Member] | As Reported [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Consolidated net (loss) income																		81,263	35,426
Adjustments to reconcile net income to net cash provided by operating activities:
Reserves on current assets																		5,718	11,408
Deferred income tax (benefit) expense																		(12,384)	26,265
Other adjustments to reconcile net income																		180,666	188,371
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable																		(29,389)	(33,250)
Inventory																		(35,300)	(22,636)
Prepaid expenses and other current assets																		(12,681)	(3,875)
Accounts payable and accrued liabilities																		(16,617)	12,325
Litigation liability																		8,150	(88,450)
Accrued payroll and related expenses																		4,088	8,849
Income taxes																		3,455	23,652
Net cash provided by operating activities																		176,969	158,085
Net cash used in investing activities																		(174,861)	(304,885)
Net cash used in financing activities																		(87,028)	110,823
Effect of exchange rate changes on cash																		2,070	(929)
Decrease in cash, cash equivalents and restricted cash																		(82,850)	(36,906)
Accounting Standards Update 2014-09 [Member] | Adjustments [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Consolidated net (loss) income																		(1,408)	45
Adjustments to reconcile net income to net cash provided by operating activities:
Reserves on current assets																		(96)	44
Deferred income tax (benefit) expense																		(454)	27
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable																		2,779	(171)
Inventory																		(567)	12
Accounts payable and accrued liabilities																		(141)	51
Accrued payroll and related expenses																		$ (113)	$ (8)
[1]	Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.
[2]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[3]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[4]	The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Organization and Significant _8

Organization and Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[2],[3],[4]	Sep. 30, 2018	[2],[3],[4]	Jun. 30, 2018	[2],[3],[4]	Mar. 31, 2018	[2],[3],[4]	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income attributable to NuVasive, Inc.									$ 23,477		$ 33,528		$ 12,167		$ 12,426		$ 12,479	$ 81,598	$ 37,192
Denominator for basic and diluted net income per share:
Weighted average common shares outstanding for basic																	51,382	50,874	50,077
Dilutive potential common stock outstanding:
Warrants																		1,494	1,297
Senior Convertible Notes																	177	1,601	1,141
Weighted average common shares outstanding for diluted																	52,355	55,193	54,102
Basic net income per share attributable to NuVasive, Inc.	$ 0.24		$ 0.31		$ 0.22		$ (0.53)		$ 0.46		$ 0.66		$ 0.24		$ 0.25		$ 0.24	$ 1.60	$ 0.74
Diluted net income per share attributable to NuVasive, Inc.	$ 0.23		$ 0.30		$ 0.22		$ (0.53)		$ 0.45		$ 0.64		$ 0.21		$ 0.22		$ 0.24	$ 1.48	$ 0.69
Stock Options and Employee Stock Purchase Plan [Member]
Dilutive potential common stock outstanding:
Incremental common shares from sharebased payments																	36	141	314
Restricted Stock Units [Member]
Dilutive potential common stock outstanding:
Incremental common shares from sharebased payments																	760	1,083	1,273
[1]	The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[2]	Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.
[3]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[4]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Organization and Significant _9

Organization and Significant Accounting Policies - Anti-dilutive Common Stock Equivalents Not Included in Calculation of Net Income Per Diluted Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	16,460	13,728	21,715
Stock Options, ESPP and Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	162	147	912
Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	10,865	10,865	13,253
Senior Convertible Notes [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	5,433	2,716	7,550

Balance Sheet Details - Propert

Balance Sheet Details - Property and Equipment Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property and equipment net
Property and equipment, gross	$ 576,382	$ 492,572
Less: accumulated depreciation and amortization	(337,541)	(277,246)
Property and equipment, net	$ 238,841	215,326
Minimum [Member]
Property and equipment net
Property and equipment, useful life	2 years
Maximum [Member]
Property and equipment net
Property and equipment, useful life	20 years
Instrument sets [Member]
Property and equipment net
Property and equipment, useful life	4 years
Property and equipment, gross	$ 326,831	287,435
Machinery and equipment [Member]
Property and equipment net
Property and equipment, gross	$ 58,585	49,142
Machinery and equipment [Member] | Minimum [Member]
Property and equipment net
Property and equipment, useful life	5 years
Machinery and equipment [Member] | Maximum [Member]
Property and equipment net
Property and equipment, useful life	7 years
Computer equipment and software [Member]
Property and equipment net
Property and equipment, gross	$ 127,539	102,729
Computer equipment and software [Member] | Minimum [Member]
Property and equipment net
Property and equipment, useful life	3 years
Computer equipment and software [Member] | Maximum [Member]
Property and equipment net
Property and equipment, useful life	7 years
Leasehold improvements [Member]
Property and equipment net
Property and equipment, gross	$ 32,973	23,532
Leasehold improvements [Member] | Minimum [Member]
Property and equipment net
Property and equipment, useful life	2 years
Leasehold improvements [Member] | Maximum [Member]
Property and equipment net
Property and equipment, useful life	15 years
Furniture and fixtures [Member]
Property and equipment net
Property and equipment, gross	$ 8,961	8,311
Furniture and fixtures [Member] | Minimum [Member]
Property and equipment net
Property and equipment, useful life	3 years
Furniture and fixtures [Member] | Maximum [Member]
Property and equipment net
Property and equipment, useful life	7 years
Building and improvements [Member]
Property and equipment net
Property and equipment, gross	$ 20,216	20,146
Building and improvements [Member] | Minimum [Member]
Property and equipment net
Property and equipment, useful life	10 years
Building and improvements [Member] | Maximum [Member]
Property and equipment net
Property and equipment, useful life	20 years
Land [Member]
Property and equipment net
Property and equipment, gross	$ 1,277	$ 1,277

Balance Sheet Details (Details

Balance Sheet Details (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Details [Abstract]
Depreciation expense	$ 75.4	$ 69.5	$ 57.1
Assets recorded under capital leases	1.5	1.8
Capitalized internal use software development costs	40.6	29.9
Capitalized internal use software amortization	10.6	10.1	7.4
Amortization expense related to intangible assets	54.4	$ 51.7	$ 45.6
Definite-lived intangible assets	26.2
Goodwill	$ 25.9

Balance Sheet Details - Goodwil

Balance Sheet Details - Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Intangible assets subject to amortization:
Weighted Average Amortization Period	9 years	9 years
Gross Amount	$ 475,083	$ 449,850
Accumulated Amortization	(223,035)	(169,076)
Intangible Assets, net	252,048	280,774
Intangible assets not subject to amortization:
Goodwill	561,366	536,926
Total goodwill and intangible assets, net	$ 813,414	$ 817,700
Developed Technology [Member]
Intangible assets subject to amortization:
Weighted Average Amortization Period	8 years	8 years
Gross Amount	$ 271,748	$ 271,748
Accumulated Amortization	(131,730)	(98,693)
Intangible Assets, net	$ 140,018	$ 173,055
Manufacturing know-how and trade secrets [Member]
Intangible assets subject to amortization:
Weighted Average Amortization Period	13 years	13 years
Gross Amount	$ 30,814	$ 30,653
Accumulated Amortization	(17,926)	(15,542)
Intangible Assets, net	$ 12,888	$ 15,111
Trade name and trademarks [Member]
Intangible assets subject to amortization:
Weighted Average Amortization Period	9 years	9 years
Gross Amount	$ 25,500	$ 25,200
Accumulated Amortization	(13,901)	(10,559)
Intangible Assets, net	$ 11,599	$ 14,641
Customer relationships [Member]
Intangible assets subject to amortization:
Weighted Average Amortization Period	9 years	9 years
Gross Amount	$ 147,021	$ 122,249
Accumulated Amortization	(59,478)	(44,282)
Intangible Assets, net	$ 87,543	$ 77,967

Balance Sheet Details - Changes

Balance Sheet Details - Changes to Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Gross goodwill	$ 569,666	$ 545,226
Accumulated impairment loss	(8,300)	(8,300)
Goodwill	561,366	$ 536,926
Changes to gross goodwill
Increases recorded in business combinations	26,959
Changes in purchase price allocation	(1,075)
Changes resulting from foreign currency fluctuations	(1,444)
Goodwill period increase (decrease)	$ 24,440

Balance Sheet Details - Future

Balance Sheet Details - Future Amortization Expense Related to Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Future amortization expense related to intangible assets
2,019	$ 52,298
2,020	51,675
2,021	49,297
2,022	41,834
2,023	17,718
Thereafter through 2031	39,226
Intangible Assets, net	$ 252,048	$ 280,774

Balance Sheet Details - Account

Balance Sheet Details - Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts payable and accrued liabilities
Accrued expenses	$ 70,386	$ 42,983
Other taxes payable	9,359	12,692
Accounts payable	8,799	4,366
Distributor commissions payable	8,194	7,697
Royalties payable	7,173	5,040
Other	1,966	2,989
Accounts payable and accrued liabilities	$ 105,877	$ 75,767

Fair Value Measurements (Detail

Fair Value Measurements (Details Textual)	1 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)	Dec. 31, 2018USD ($)investment	Dec. 31, 2017USD ($)investment	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Unrealized loss position investment | investment		0	0
Impairment charges recorded for earnings		$ 0	$ 0
Net currency exchange gains (losses) from derivatives instruments		(3,700,000)	(900,000)	$ (300,000)
Contingent consideration liabilities		7,560,000	18,952,000
Increased fair value adjustments		(300,000)	(11,200,000)
Purchased in-process research and development asset		8,913,000
Net loss on strategic investments		3,800,000
Non-Financial Assets and Liabilities Measured on a Nonrecurring Basis [Member]
Business Acquisition [Line Items]
Accrual related to capital lease obligations		0	0
LessRay Software Technology Inc [Member]
Business Acquisition [Line Items]
Payments of outstanding milestone obligation		19,000,000
Payments of outstanding milestone related to achievement of commercial milestone		9,000,000
Payments of outstanding milestone related to achievement of regulatory approval milestone		10,000,000
LessRay Software Technology Inc [Member] | ASU 2016-15 [Member]
Business Acquisition [Line Items]
Payments for initial purchase price allocation		18,700,000
Increased fair value adjustments		(300,000)
Ellipse Technologies Inc [Member]
Business Acquisition [Line Items]
Payments of outstanding milestone obligation			30,000,000
Ellipse Technologies Inc [Member] | ASU 2016-15 [Member]
Business Acquisition [Line Items]
Payments for initial purchase price allocation		18,800,000
Increased fair value adjustments		(11,200,000)
Contingent Consideration Liabilities [Member]
Business Acquisition [Line Items]
Contingent consideration liabilities		50,400,000	67,900,000
Additions to contingent consideration liabilities with acquisitions			32,600,000
Contingent consideration liability recorded upon acquisition	$ 31,400,000	3,543,000	32,559,000
Convertible Notes due 2021 [Member] | Quoted Price in Active Market (Level 1) [Member]
Business Acquisition [Line Items]
Debt instrument, fair value disclosure		684,800,000	779,500,000
Foreign Exchange Forward [Member]
Business Acquisition [Line Items]
Notional principal amount		26,800,000	14,300,000	15,100,000
Foreign Exchange Forward [Member] | Other Current Assets or Other Current Liabilities [Member]
Business Acquisition [Line Items]
Fair value of derivative instrument asset (liability)		(300,000)	(100,000)
Foreign Exchange Forward [Member] | Other (Expense) Income [Member]
Business Acquisition [Line Items]
Net (losses) gains recognized on derivative instruments		$ 500,000	$ (1,900,000)	$ 700,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Assets and Liabilities (Details) - Fair Value Measurements on Recurring Basis [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Cash Equivalents and Marketable Securities
Total cash equivalents	$ 56,000	$ 27,000
Money Market Funds [Member]
Cash Equivalents and Marketable Securities
Total cash equivalents	56,000	27,000
Quoted Price in Active Market (Level 1) [Member]
Cash Equivalents and Marketable Securities
Total cash equivalents	56,000	27,000
Quoted Price in Active Market (Level 1) [Member] | Money Market Funds [Member]
Cash Equivalents and Marketable Securities
Total cash equivalents	$ 56,000	$ 27,000

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Value of Liabilities Measured on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - Contingent Consideration Liabilities [Member] - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement at beginning of period		$ 67,941	$ 67,501
Contingent consideration liability recorded upon acquisition	$ 31,400	3,543	32,559
Change in fair value measurement		(1,517)	(1,295)
Changes resulting from foreign currency fluctuations		193	(224)
Contingent consideration paid or settled		(19,750)	(30,600)
Fair value measurement at end of period		$ 50,410	$ 67,941

Business Combinations (Details

Business Combinations (Details Textual) - Progentix Orthobiology [Member] - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2009	Jan. 31, 2018
Business Acquisition [Line Items]
Percentage of ownership Interests acquired			60.00%
Advanced loan accordance to loan agreement	$ 5,300,000
Accrued interest rate of loan	6.00%
Ownership percentage	100.00%
Preferred Stock Purchase Agreement [Member]
Business Acquisition [Line Items]
Percentage of ownership Interests acquired		40.00%
Cash payment on purchase of outstanding shares		$ 10,000,000

Reconciliation of Equity Attrib

Reconciliation of Equity Attributable to the Non-controlling Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of equity attributable to the non-controlling interests
Non-controlling interests at beginning of period	$ 3,845
Less: net loss attributable to the non-controlling interests		$ (1,743)	$ (1,721)
Non-controlling interests at end of period		3,845
Variable Interest Entity [Member]
Reconciliation of equity attributable to the non-controlling interests
Non-controlling interests at beginning of period	3,845	5,588
Acquired non-controlling interest reclassified to additional paid-in capital	$ (3,845)
Less: net loss attributable to the non-controlling interests		(1,743)
Non-controlling interests at end of period		$ 3,845	$ 5,588

Business Combinations Total ass

Business Combinations Total assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Total current assets	$ 618,209	$ 560,063
Goodwill	$ 561,366	536,926
Deferred tax liabilities, net		7,773
Non-controlling interests		3,845
Variable Interest Entity [Member]
Business Acquisition [Line Items]
Non-controlling interests		3,845	$ 5,588
Variable Interest Entity [Member] | Progentix Orthobiology [Member]
Business Acquisition [Line Items]
Total current assets		670
Identifiable intangible assets, net		8,752
Goodwill		12,654
Accounts payable & accrued expenses		562
Deferred tax liabilities, net		331
Non-controlling interests		$ 3,845

Carrying Value of Senior Conver

Carrying Value of Senior Convertible Notes (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2016
Debt Instrument [Line Items]
Total Senior Convertible Notes	$ 602,526,000	$ 582,920,000
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal amount	650,000,000	650,000,000	$ 650,000,000
Unamortized debt discount	(40,117,000)	(56,839,000)
Unamortized debt issuance costs	$ (7,357,000)	$ (10,241,000)

Carrying Value of Senior Conv_2

Carrying Value of Senior Convertible Notes (Parenthetical) (Details)	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2016
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member]
Debt Instrument [Line Items]
Interest rate on convertible notes	2.25%	2.25%	2.25%

Indebtedness (Details Textual)

Indebtedness (Details Textual)	1 Months Ended			12 Months Ended
	Apr. 30, 2017USD ($)	Mar. 31, 2016USD ($)$ / shares	Jun. 30, 2011USD ($)$ / shares	Dec. 31, 2018USD ($)d$ / sharesshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2011$ / sharesshares
Debt Instrument [Line Items]
Proceeds from issuance of convertible debt, net of issuance costs						$ 634,140,000
Stock price | $ / shares				$ 49.56
Cash proceeds from the sale of warrants						44,850,000
Cumulative loss on repurchase of senior convertible notes						19,085,000
Revolving Senior Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 500,000,000
Credit facility, expiration date				2022-04
Revolving loan outstanding				$ 0	$ 0
Revolving Senior Credit Facility [Member] | Federal Funds Effective Rate [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	0.50%
Revolving Senior Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	1.00%
Multicurrency Borrowings [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 100,000,000
Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	50,000,000
Swing Line Loans [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 5,000,000
2021 Warrants [Member]
Debt Instrument [Line Items]
Cash proceeds from the sale of warrants		$ 44,900,000
Warrant strike price | $ / shares		$ 80
2017 Warrants [Member]
Debt Instrument [Line Items]
Warrant strike price | $ / shares				$ 988.51
2017 Warrants [Member] | Series A Convertible Participating Preferred Stock [Member]
Debt Instrument [Line Items]
Number of common stock shares preferred stock convertible into | shares				20
2021 Hedge [Member]
Debt Instrument [Line Items]
Number of common stock to be purchased | shares				10,865,270
Stock price | $ / shares				$ 59.82
Derivative, maturity date				Mar. 15, 2021
2017 Hedge [Member]
Debt Instrument [Line Items]
Number of common stock to be purchased | shares							9,553,096
Stock price | $ / shares							$ 42.13
Minimum [Member] | Revolving Senior Credit Facility [Member]
Debt Instrument [Line Items]
Unused line fee	0.20%
Minimum [Member] | Revolving Senior Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	0.00%
Minimum [Member] | Revolving Senior Credit Facility [Member] | Eurocurrency [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	1.00%
Minimum [Member] | 2021 Warrants [Member]
Debt Instrument [Line Items]
Class of warrant or rights expiry month and year				2021-06
Minimum [Member] | 2017 Warrants [Member]
Debt Instrument [Line Items]
Class of warrant or rights expiry month and year				2017-09
Maximum [Member] | Revolving Senior Credit Facility [Member]
Debt Instrument [Line Items]
Unused line fee	0.35%
Maximum [Member] | Revolving Senior Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	1.00%
Maximum [Member] | Revolving Senior Credit Facility [Member] | Eurocurrency [Member]
Debt Instrument [Line Items]
Credit facility bear interest rate	2.00%
Maximum [Member] | 2021 Warrants [Member]
Debt Instrument [Line Items]
Class of warrant or rights expiry month and year				2021-12
Maximum [Member] | 2017 Warrants [Member]
Debt Instrument [Line Items]
Class of warrant or rights expiry month and year				2018-01
Maximum [Member] | 2017 Warrants [Member] | Series A Convertible Participating Preferred Stock [Member]
Debt Instrument [Line Items]
Number of preferred or common stock into which the warrants is converted | shares				477,654
Additional Paid-in Capital [Member] | 2021 Hedge [Member]
Debt Instrument [Line Items]
Cost of hedge transaction						111,200,000
Common Shares [Member] | Maximum [Member] | 2021 Warrants [Member]
Debt Instrument [Line Items]
Number of preferred or common stock into which the warrants is converted | shares				10,865,270
Common Shares [Member] | Maximum [Member] | 2017 Warrants [Member]
Debt Instrument [Line Items]
Number of preferred or common stock into which the warrants is converted | shares				9,553,080
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal amount		$ 650,000,000		$ 650,000,000	$ 650,000,000
Proceeds from issuance of convertible debt, net of issuance costs		$ 634,100,000
Interest rate on convertible notes		2.25%		2.25%	2.25%
Debt instrument, maturity date		Mar. 15, 2021
Initial conversion rate adjustment, shares		16.7158
Principal amount of debt considered for conversion rate		$ 1,000
Initial conversion price of convertible notes | $ / shares		$ 59.82
Contractual coupon interest expense				$ 14,600,000	$ 14,600,000	11,500,000
Amortization of debt discount (premium)				16,700,000	15,900,000	12,100,000
Amortization of debt issuance costs				$ 2,900,000	2,600,000	1,900,000
Effective interest rate				5.80%
Debt redemption price percentage				100.00%
Principal payments due				$ 0
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Scenario Two [Member]
Debt Instrument [Line Items]
Consecutive trading days considered for debt conversion | d				5
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Percentage of conversion price				130.00%
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Minimum [Member] | Scenario One [Member]
Debt Instrument [Line Items]
Consecutive trading days considered for debt conversion | d				20
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of conversion price				98.00%
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Maximum [Member] | Scenario One [Member]
Debt Instrument [Line Items]
Consecutive trading days considered for debt conversion | d				30
2.25% Senior Convertible Notes [Member] | Convertible Notes due 2021 [Member] | Additional Paid-in Capital [Member]
Debt Instrument [Line Items]
Amount reclassified to stockholders' equity						84,800,000
2.75% Senior Convertible Notes [Member] | Convertible Notes due 2017 [Member]
Debt Instrument [Line Items]
Principal amount			$ 402,500,000
Interest rate on convertible notes			2.75%
Debt instrument, maturity date			Jul. 1, 2017
Initial conversion rate adjustment, shares			23.7344
Principal amount of debt considered for conversion rate			$ 1,000
Initial conversion price of convertible notes | $ / shares			$ 42.13
Contractual coupon interest expense					900,000	4,900,000
Amortization of debt discount (premium)					1,400,000	7,500,000
Amortization of debt issuance costs					$ 200,000	1,000,000
Effective interest rate				8.00%
2.75% Senior Convertible Notes [Member] | Convertible Notes due 2017 [Member] | Other Expense [Member]
Debt Instrument [Line Items]
Cumulative loss on repurchase of senior convertible notes						$ 19,100,000

Commitments (Details Textual)

Commitments (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies Disclosure [Line Items]
Restricted cash for security deposit	$ 2.4	$ 5.4
Rent expense	12.8	$ 12.6	$ 10.6
Licensing and Purchasing Agreements [Member]
Commitments And Contingencies Disclosure [Line Items]
Maximum payment the company has minimum and contingent obligations to make due to several purchase agreements	75.2
Executive Severance Plans [Member]
Commitments And Contingencies Disclosure [Line Items]
Other commitments, future minimum payments, remainder of fiscal year	$ 15
Minimum [Member]
Commitments And Contingencies Disclosure [Line Items]
Initial terms of lease	2 years
Maximum [Member]
Commitments And Contingencies Disclosure [Line Items]
Initial terms of lease	17 years

Commitments - Future Minimum Le

Commitments - Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2018USD ($)
Capital Leases
2,019	$ 534
2,020	507
2,021	244
2,022	24
2,023	5
Total minimum lease payments	1,314
Less amount representing interest	(59)
Present value of obligations under capital leases	1,255
Less current portion	(449)
Long-term capital lease obligations	806
Operating Leases
2,019	13,750
2,020	13,007
2,021	10,954
2,022	10,578
2,023	10,515
Thereafter	116,684
Total minimum lease payments	$ 175,488

Stockholders' Equity (Details T

Stockholders' Equity (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 28, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized	120,000,000	120,000,000
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Preferred stock, par value	$ 0.001	$ 0.001
Closing price of stock	$ 49.56
Proceeds from exercise of stock options	$ 1,300,000	$ 2,400,000	$ 3,000,000
Total intrinsic value	$ 2,500,000	$ 8,300,000	$ 29,000,000
Total stock options vested	0	0	0
Total shares reserved for future issuance	54,069,000
ESPP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized cost related to share-based compensation	$ 900,000
Maximum percentage of annual compensation	15.00%
Maximum amount withheld to purchase shares of the company	$ 21,250
Percentage of issuance price of stock under the stock issuance program	85.00%
ESPP offering period	6 months
Number of share purchased under ESPP	151,000	154,000	152,000
Total shares reserved for future issuance	1,093,000
2014 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of acceleration of stock options in case of change in control	50.00%
Total shares reserved for future issuance			2,200,000
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized cost related to share-based compensation	$ 25,100,000
Weighted average contractual term	1 year 10 months 24 days
Fair value of restricted stock units vested	$ 8,800,000	$ 19,900,000	$ 31,200,000
Total shares withheld related to statutory tax	42,000	103,000	227,000
Payments of employees tax obligations	$ 2,200,000	$ 7,200,000	$ 11,400,000
Vested during the period	169,000
Performance-Based Restricted Stock Units (PRSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized cost related to share-based compensation	$ 14,400,000
Weighted average contractual term	2 years 7 months 6 days
Fair value of restricted stock units vested	$ 2,100,000	$ 10,300,000	$ 12,600,000
Total shares withheld related to statutory tax	8,000	35,000	58,000
Payments of employees tax obligations	$ 400,000	$ 2,500,000	$ 2,700,000
Vested during the period	21,000	76,000	145,000
Vesting period for the awards	5 years			5 years
Performance-Based Restricted Stock Units (PRSUs) [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share payout levels	0.00%
Performance-Based Restricted Stock Units (PRSUs) [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share payout levels	312.50%
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized cost related to share-based compensation	$ 0
Total shares withheld related to statutory tax	65,000	105,000	1,157,000
Payments of employees tax obligations	$ 400,000	$ 2,100,000	$ 10,700,000
Total shares reserved for future issuance	49,000
Series A Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Preferred stock, shares authorized					477,654
Preferred stock, par value					$ 0.001
Shares issued on conversion					20
Preferred stock, liquidation preference per share					$ 648.20

Stockholders' Equity - Stock Co

Stockholders' Equity - Stock Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 25,673	$ 22,391	$ 26,924
Related income tax benefits	(6,418)	(8,509)	(10,770)
Stock-based compensation expense, net of taxes	19,255	13,882	16,154
Sales, Marketing and Administrative Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	22,190	20,596	25,466
Research and Development Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	3,052	1,445	1,231
Cost of Goods Sold [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 431	$ 350	$ 227

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Award Activity (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average grant date fair value outstanding, Beginning balance | $ / shares	$ 52.90
Weighted average grant date fair value, Granted | $ / shares	55.55
Weighted average grant date fair value, Vested | $ / shares	42.94
Weighted average grant date fair value, Forfeited | $ / shares	55.63
Weighted average grant date fair value outstanding, Ending balance | $ / shares	$ 55.25
Restricted Stock Units
Number of shares outstanding, Beginning balance | shares	996
Number of shares, Granted | shares	467
Number of shares, Vested | shares	(169)
Number of shares, Forfeited | shares	(180)
Number of shares outstanding, Ending balance | shares	1,114

Stockholders' Equity - Performa

Stockholders' Equity - Performance-Based Restricted Stock Award Activity (Details) - Performance-Based Restricted Stock Units (PRSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding, Beginning balance	765,000
Shares, Awarded at target	369,000
Number of shares, Vested	(21,000)	(76,000)	(145,000)
Number of shares, Forfeited	(126,000)
Number of shares outstanding, Ending balance	987,000	765,000
Maximum Number of Shares Eligible to be Issued, Outstanding, Beginning balance	1,462,000
Maximum Number of Shares Eligible to be Issued, Awarded at target	479,000
Maximum Number of Shares Eligible to be Issued, Vested	(21,000)
Maximum Number of Shares Eligible to be Issued, Forfeited	(262,000)
Maximum Number of Shares Eligible to be Issued, Outstanding, Ending balance	1,658,000	1,462,000
Weighted average grant date fair value outstanding, Beginning balance	$ 52.62
Average Grant Date Fair Value, Awarded at target	54.86
Average Grant Date Fair Value, Vested	48.73
Average Grant Date Fair Value, Forfeited	55.39
Weighted average grant date fair value outstanding, Ending balance	$ 56.88	$ 52.62

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Summary of stock option activity under all stock plans
Underlying shares outstanding, Beginning balance	178
Underlying shares, exercised	(128)
Underlying shares, cancelled	(1)
Underlying shares outstanding, Ending balance	49	178
Underlying shares exercisable, Ending balance	49
Underlying shares vested or expected to vest, Ending balance	49
Weighted average exercise price outstanding, Beginning balance	$ 35.41
Weighted Average Exercise Price, exercised	35.28
Weighted Average Exercise Price, cancelled	34.49
Weighted Average Exercise Price outstanding, Ending balance	35.76	$ 35.41
Weighted Average Exercise Price option exercisable, Ending balance	35.76
Weighted Average Exercise price vested or expected to vest, Ending balance	$ 35.76
Weighted Average Remaining Contractual Term outstanding, Beginning balance	1 year 6 months 7 days	1 year 3 months 29 days
Weighted Average Remaining Contractual Term exercisable, Ending balance	1 year 6 months 7 days
Weighted Average Remaining Contractual Term vested or expected to vest, Ending balance	1 year 6 months 7 days
Aggregate Intrinsic Value outstanding	$ 680	$ 4,105
Aggregate intrinsic value exercisable	680
Aggregate intrinsic value vested or expected to vest	$ 680

Stockholders' Equity - Assumpti

Stockholders' Equity - Assumptions Table (Details) - ESPP [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP
Volatility	33.00%	26.00%	29.00%
Expected term (years)	6 months	6 months	6 months
Risk free interest rate	1.80%	0.90%	0.40%

Stockholders' Equity - Stock Re

Stockholders' Equity - Stock Reserved for Future Issuance (Details) shares in Thousands	Dec. 31, 2018shares
Common stock options:
Shares reserved for future issuance	54,069
Stock Options [Member]
Common stock options:
Shares reserved for future issuance	49
Restricted Stock Units And Performance-Based Restricted Stock Units [Member]
Common stock options:
Shares reserved for future issuance	2,183
Available for Future Grant [Member]
Common stock options:
Shares reserved for future issuance	3,752
ESPP [Member]
Common stock options:
Shares reserved for future issuance	1,093
2.25% Senior Convertible Notes due 2021 [Member]
Common stock options:
Shares reserved for future issuance	14,396
Senior Convertible Warrants Due 2021 [Member]
Common stock options:
Shares reserved for future issuance	32,596

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Before Income Taxes By Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summarized details of income before income taxes by region
United States	$ 8,939	$ 76,480	$ 77,610
Foreign	(216)	(4,117)	(12,830)
Income before income taxes	$ 8,723	$ 72,363	$ 64,780

Income Taxes - Components of In

Income Taxes - Components of Income Tax (Benefit) Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (4,188)	$ 5,972	$ (14,837)
State	2,043	776	1,283
Foreign	5,972	2,793	2,350
Total current provision	3,827	9,541	(11,204)
Deferred:
Federal	(5,944)	(1,565)	40,363
State	(7,092)	(4,276)	1,455
Foreign	(98,795)	(2,223)	(2,583)
Total deferred provision	(111,831)	(8,064)	39,235
Changes in tax rate	258	(14,668)	(216)
Changes in valuation allowance	103,990	5,699	1,494
Total (benefit) provision	$ (3,756)	$ (7,492)	$ 29,309

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax from Statutory Tax Rate to Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax provision at federal statutory rate	$ 1,832	$ 25,327	$ 22,673
Valuation allowance	103,990	5,703	1,494
Net tax benefit on international restructuring	(97,028)
Income tax reserves	(6,717)	1,184	759
Income tax credits and incentives	(5,525)	(3,462)	(3,426)
Return to provision adjustments	(4,180)	(2,443)	(1,188)
Compensation expense	2,008	(5,619)	(8,013)
Globalization initiative	1,264	306	6,290
Nondeductible meals and entertainment	769	922	1,013
Foreign tax rate differences from federal statutory rate	(688)	378	605
Changes in tax rate	258	(14,668)	(216)
Acquisition related charges	(221)	(489)	5,167
State income tax	90	3,553	3,245
Recovery of tax basis in United States subsidiary		(19,540)
Other	392	1,356	906
Total (benefit) provision	$ (3,756)	$ (7,492)	$ 29,309

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Amortization	$ 106,769	$ 6,742
General business and other credit carryforwards	25,846	18,928
Stock-based compensation	14,914	13,502
Inventory	12,385	10,075
Net operating loss carryforwards	7,516	14,991
Deferred rent	4,628	2,532
Original issue discount	3,322	4,606
Other	23,241	14,859
Gross deferred tax assets	198,621	86,235
Less valuation allowance	(120,233)	(16,247)
Net deferred tax assets	78,388	69,988
Deferred tax liabilities:
Acquired intangibles	(42,767)	(53,076)
Depreciation	(32,851)	(23,132)
Other	(1,843)	(1,752)
Total deferred tax liabilities	(77,461)	(77,960)
Consolidated net deferred tax assets	927
Deferred Tax Liabilities Including Portion Attributable To Non Controlling Interest		(7,972)
Add deferred tax liability, net, attributable to non-controlling interests		199
Net deferred tax assets	$ 927
Net deferred tax liabilities		$ (7,773)

Income Taxes - Summary of Unrec

Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Gross unrecognized tax benefits at beginning of period	$ 25,356	$ 23,322	$ 12,448
Increases in tax positions for prior years	499	1,692	1,716
Decreases in tax positions for prior years	(756)	(24)	(270)
Increases in tax positions for current year relating to ongoing operations	1,913	968	6,205
Decreases in tax positions as a result of a lapse of statute of limitations	(6,446)	(402)
Increases in tax positions for current year relating to acquisitions	169		3,223
Decreases in tax positions due to settlements with taxing authorities	(1,190)	(200)
Gross unrecognized tax benefits period end	$ 19,545	$ 25,356	$ 23,322

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2018
Income Taxes [Line Items]
Unrecognized tax benefits that would impact effective tax	$ 18,100	$ 24,100	$ 12,500
Income tax, penalties and interest (benefit) expense	(500)	(100)	$ 300
Income tax, penalties and interest accrued	100	400
Remaining unrecognized tax positions	800
Deferred tax assets	198,621	86,235
Valuation allowance for deferred tax assets	120,233	$ 16,247
Income tax benefit associated with change in tax rate	300
Increase in effective tax rate		0.50%
California Tax Authority [Member]
Income Taxes [Line Items]
Valuation allowance reserves recorded against net operating losses	53,800
Net operating losses	53,800
Net research and development carryforwards	25,900
Valuation allowance reserves on tax credit carry forward amount	25,900
Federal Tax Authority [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 2,300
Operating loss carryforwards expiration year	2,020
Net research and development carryforwards	$ 22,300
Federal tax credit carryforwards, expiration year	2,027
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 71,800
Operating loss carryforwards expiration year	2,020
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 6,800
Operating loss carryforwards expiration year	2,020
ASU 2016-16 [Member]
Income Taxes [Line Items]
Deferred tax assets				$ 100,800
Valuation allowance for deferred tax assets				$ 96,700

Business Segment, Product and_2

Business Segment, Product and Geographic Information (Details Textual)	12 Months Ended
	Dec. 31, 2018segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

Business Segment, Product and_3

Business Segment, Product and Geographic Information - Schedule of Revenue by Product Lines (Details) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2018

[1],[2],[3]

Sep. 30, 2018

[1],[2],[3]

Jun. 30, 2018

[1],[2],[3]

Mar. 31, 2018

[1],[2],[3]

Dec. 31, 2017

[4]

Sep. 30, 2017

[4]

Jun. 30, 2017

[4]

Mar. 31, 2017

[4]

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Entity Wide Information Revenue From External Customer [Line Items]

Total revenue

$ 288,327

$ 271,301

$ 281,564

$ 260,522

$ 271,222

$ 247,051

$ 259,399

$ 249,013

$ 1,101,714

$ 1,026,685

$ 962,132

Spinal Hardware [Member]

Entity Wide Information Revenue From External Customer [Line Items]

Total revenue

788,650

737,534

683,703

Surgical Support [Member]

Entity Wide Information Revenue From External Customer [Line Items]

Total revenue

$ 313,064

$ 289,151

$ 278,429

[1]

Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.

[2]

The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

[3]

The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

[4]

The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Business Segment, Product and_4

Business Segment, Product and Geographic Information - Schedule of Revenue and Net Property and Equipment by Geographical Area (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018	[1],[2],[3]	Jun. 30, 2018	[1],[2],[3]	Mar. 31, 2018	[1],[2],[3]	Dec. 31, 2017		Sep. 30, 2017	[4]	Jun. 30, 2017	[4]	Mar. 31, 2017	[4]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Revenue	$ 288,327	[1],[2],[3]	$ 271,301		$ 281,564		$ 260,522		$ 271,222	[4]	$ 247,051		$ 259,399		$ 249,013		$ 1,101,714	$ 1,026,685	$ 962,132
Property and Equipment, Net	238,841								215,326								238,841	215,326
United States
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Revenue																	896,152	850,410	831,778
Property and Equipment, Net	200,404								179,891								200,404	179,891
International [Member]
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Revenue																	205,562	176,275	$ 130,354
Property and Equipment, Net	$ 38,437								$ 35,435								$ 38,437	$ 35,435
[1]	Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.
[2]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[3]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[4]	The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Contingencies (Details)

Contingencies (Details) - USD ($)	Dec. 06, 2018	Feb. 13, 2018	Jul. 05, 2016	Mar. 18, 2016	Feb. 19, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 31, 2018	Mar. 31, 2018
Loss Contingencies [Line Items]
Litigation accrual						$ 1,415,000	$ 8,150,000
Litigation accrual adjustment						(27,800,000)	(4,500,000)	$ 43,310,000
Madsen Medical, Inc. Litigation [Member]
Loss Contingencies [Line Items]
Settlement agreement, consideration						27,800,000
Litigation accrual									$ 27,800,000	$ 29,000,000
Litigation accrual adjustment						$ 27,800,000
Jury award				$ 27,800,000
Loss contingency, settlement agreement, court						On March 18, 2016, the trial court entered judgment in favor of MMI in the amount of $27.8 million, which amount excluded the $14.0 million disgorgement awarded by the jury
Madsen Medical, Inc. Litigation [Member] | Loss Profits for Tortious Interference [Member]
Loss Contingencies [Line Items]
Jury award					$ 7,500,000
Madsen Medical, Inc. Litigation [Member] | Unjust Enrichment [Member]
Loss Contingencies [Line Items]
Jury award					14,000,000
Madsen Medical, Inc. Litigation [Member] | Punitive Damages [Member]
Loss Contingencies [Line Items]
Jury award					20,000,000
Madsen Medical, Inc. Litigation [Member] | Damages for Breach of Contract [Member]
Loss Contingencies [Line Items]
Jury award					$ 300,000
Madsen Medical, Inc. Litigation [Member] | Attorney Fees And Costs [Member]
Loss Contingencies [Line Items]
Jury award			$ 1,100,000
Madsen Medical, Inc. Litigation [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss							0			0
Madsen Medical, Inc. Litigation [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss										$ 29,000,000
Medtronic Litigation [Member]
Loss Contingencies [Line Items]
Settlement agreement, consideration							$ 4,500,000
Litigation accrual adjustment								43,300,000
Medtronic Litigation [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Litigation accrual								45,000,000
Medtronic Litigation [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Litigation accrual								$ 88,300,000
Securities Litigation [Member]
Loss Contingencies [Line Items]
Settlement agreement, consideration		$ 7,900,000
Settlement funded by insurance proceeds	$ 7,900,000

Quarterly Data (unaudited) (Det

Quarterly Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1],[2],[3]	Sep. 30, 2018	[1],[2],[3]	Jun. 30, 2018	[1],[2],[3]	Mar. 31, 2018	[1],[2],[3]	Dec. 31, 2017	[4]	Sep. 30, 2017	[4]	Jun. 30, 2017	[4]	Mar. 31, 2017	[4]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 288,327		$ 271,301		$ 281,564		$ 260,522		$ 271,222		$ 247,051		$ 259,399		$ 249,013		$ 1,101,714	$ 1,026,685	$ 962,132
Gross profit	202,198		197,141		204,508		186,708		195,917		181,544		193,213		187,570		790,555	758,244	722,027
Consolidated net (loss) income	$ 12,157		$ 15,923		$ 11,531		$ (27,132)		23,041		33,096		11,735		11,983		12,479	79,855	35,471
Net income attributable to NuVasive, Inc.									$ 23,477		$ 33,528		$ 12,167		$ 12,426		$ 12,479	$ 81,598	$ 37,192
Basic net (loss) income per common	$ 0.24		$ 0.31		$ 0.22		$ (0.53)		$ 0.46		$ 0.66		$ 0.24		$ 0.25		$ 0.24	$ 1.60	$ 0.74
Diluted net (loss) income per common share	$ 0.23		$ 0.30		$ 0.22		$ (0.53)		$ 0.45		$ 0.64		$ 0.21		$ 0.22		$ 0.24	$ 1.48	$ 0.69
[1]	Consolidated financial results include a litigation charge of $27.8 million in connection with the settlement of all outstanding litigation matters with Madsen Medical, Inc.
[2]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 does not contain any results attributable to non-controlling interests. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[3]	The unaudited quarterly financial data set forth for the year ended December 31, 2018 includes the operations and results of the Company’s 2018 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.
[4]	The unaudited quarterly financial data set forth for the year ended December 31, 2017 includes the operations and results of the Company’s 2017 acquisitions from their respective dates of acquisition. See Note 4 to the Consolidated Financial Statements included in this Annual Report for further discussion.

Quarterly Data (unaudited) (Par

Quarterly Data (unaudited) (Paranthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information [Line Items]
Litigation charge in connection with settlement	$ (27,800)	$ (4,500)	$ 43,310
Madsen Medical, Inc. Litigation [Member]
Quarterly Financial Information [Line Items]
Litigation charge in connection with settlement	$ 27,800