Nuvasive (NUVA) 10-Q 30 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 21, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	NUVASIVE INC
Entity Central Index Key	1142596
Document Type	10-Q
Document Period End Date	30-Sep-13
Amendment Flag	FALSE
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		44,618,891

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$100,616	$123,299
Short-term marketable securities	109,214	138,405
Accounts receivable, net	96,208	88,958
Inventory	140,709	126,335
Deferred tax assets, current	31,136	28,236
Prepaid expenses and other current assets	10,100	8,516
Total current assets	487,983	513,749
Property and equipment, net	130,796	125,123
Long-term marketable securities	92,999	84,412
Intangible assets, net	93,037	101,362
Goodwill	154,913	154,106
Deferred tax assets	39,719	40,575
Restricted cash and investments	119,168	118,995
Other assets	21,624	25,463
Total assets	1,140,239	1,163,785
Current liabilities:
Accounts payable and accrued liabilities	81,820	62,048
Accrued payroll and related expenses	26,117	27,916
Senior Convertible Notes, current	0	74,311
Total current liabilities	107,937	164,275
Senior Convertible Notes	342,552	332,404
Deferred tax liabilities	3,143	3,129
Litigation liability	93,700	101,200
Other long-term liabilities	14,789	15,199
Commitments and contingencies
Noncontrolling interests	0	10,003
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000 shares authorized, none outstanding	0	0
Common stock, $0.001 par value; 120,000 shares authorized at September 30, 2013 and December 31, 2012, 44,596 and 43,686 issued and outstanding at September 30, 2013 and December 31, 2012, respectively	45	44
Additional paid-in capital	746,518	714,865
Accumulated other comprehensive (loss) income	-1,476	786
Accumulated deficit	-176,227	-178,120
Noncontrolling Interest in Variable Interest Entity	9,258	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	578,118	537,575
Total stockholders' equity	568,860	537,575
Total liabilities and stockholders' equity	$1,140,239	$1,163,785

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Preferred stock, par value (in usd per share)	$0.00	$0.00
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in usd per share)	$0.00	$0.00
Common stock, shares authorized	120,000	120,000
Common stock, shares issued	44,596	43,686
Common stock, shares outstanding	44,596	43,686

Unaudited_Condensed_Consolidat

Unaudited Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue	$169,156	$148,391	$494,358	$454,501
Cost of goods sold (excluding amortization of purchased technology)	43,291	37,746	131,131	111,213
Gross profit	125,865	110,645	363,227	343,288
Operating expenses:
Sales, marketing and administrative	102,085	87,410	306,243	274,703
Research and development	7,248	7,575	24,654	26,898
Amortization of intangible assets	4,974	3,081	14,263	8,830
Total operating expenses	114,307	98,066	345,160	310,431
Interest and other expense, net:
Interest income	157	249	560	661
Interest expense	-6,712	-6,885	-20,396	-20,682
Other income, net	3,137	260	2,937	146
Total interest and other expense, net	-3,418	-6,376	-16,899	-19,875
Income before income taxes	8,140	6,203	1,168	12,982
Income tax expense	860	4,064	20	7,764
Consolidated net income	7,280	2,139	1,148	5,218
Net loss attributable to noncontrolling interests	-231	-215	-745	-672
Net income attributable to NuVasive, Inc.	$7,511	$2,354	$1,893	$5,890
Net income per share attributable to NuVasive, Inc.:
Earnings Per Share, Basic	$0.17	$0.05	$0.04	$0.14
Earnings Per Share, Diluted	$0.16	$0.05	$0.04	$0.13
Weighted average shares outstanding:
Basic (in shares)	44,572	43,488	44,339	43,227
Diluted (in shares)	47,220	44,735	46,387	44,151

Unaudited_Condensed_Consolidat1

Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Consolidated net income	$7,280	$2,139	$1,148	$5,218
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net of tax	283	102	13	-43
Translation adjustments, net of tax	1,654	1,029	-2,275	732
Other comprehensive income (loss)	1,937	1,131	-2,262	689
Total consolidated comprehensive income (loss)	9,217	3,270	-1,114	5,907
Plus: Net loss attributable to noncontrolling interests	231	215	745	672
Comprehensive income (loss) attributable to NuVasive, Inc.	$9,448	$3,485	($369)	$6,579

Unaudited_Condensed_Consolidat2

Unaudited Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Consolidated net income	$1,148	$5,218
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	46,289	38,237
Amortization of debt discount	10,148	9,435
Amortization of debt issuance costs	1,265	1,386
Stock-based compensation	24,002	20,400
Allowance for doubtful accounts and sales return reserves	665	816
Allowance for excess and obsolete inventory, net of write-offs	1,984	2,000
Other non-cash adjustments	3,881	5,002
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	-8,253	8,421
Inventory	-16,749	-14,222
Prepaid expenses and other current assets	-2,838	13,582
Accounts payable and accrued liabilities	10,415	9,480
Accrued payroll and related expenses	-1,824	-269
Net cash provided by operating activities	70,133	99,486
Investing activities:
Cash paid for business and asset acquisitions	-8,019	-9,838
Purchases of property and equipment	-38,018	-35,706
Purchases of marketable securities	-164,338	-192,759
Sales of marketable securities	-183,756	-193,035
Payments to Acquire Restricted Investments	0	113,331
Net cash used in investing activities	-26,619	-158,599
Financing activities:
Principal payment of 2013 Senior Convertible Notes	-74,311	0
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	5,247	0
Proceeds from the issuance of common stock	3,492	3,183
Other assets	-72	132
Net cash (used in) provided by financing activities	-65,644	3,315
Effect of exchange rate changes on cash	-553	37
Decrease in cash and cash equivalents	-22,683	-55,761
Cash and cash equivalents at beginning of period	123,299	163,492
Cash and cash equivalents at end of period	100,616	107,731
Supplemental disclosure of non-cash transactions:
Issuance of common stock in connection with asset acquisitions	$0	$7,560

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation
	Description of Business.    NuVasive, Inc. (the Company or NuVasive) was incorporated in Delaware on July 21, 1997, and began commercializing its products in 2001. The Company is focused on developing minimally disruptive surgical products and procedurally integrated solutions for the spine. NuVasive's principal product offering includes a minimally disruptive surgical platform called Maximum Access Surgery, or MAS®, as well as an offering of biologics, cervical and motion preservation products. The MAS platform combines three categories of solutions that collectively minimize soft tissue disruption during spine fusion surgery, provide maximum visualization and are designed to enable reproducible outcomes for the surgeon. The platform includes a proprietary software-driven nerve detection and avoidance systems, NVM5 and NVJJB, and Intra-Operative Monitoring (IOM) support; MaXcess®, a unique and integrated split-blade retractor system; and a wide variety of specialized implants. When the three elements of MAS are used together, they may significantly reduce surgery time and return patients to activities of daily living much faster than conventional approaches. The individual components of NuVasive's MAS platform, and many of the Company's products, can also be used in open or traditional spine surgery and may independently offer patient benefits to various surgical approaches dealing with a wide variety of pathologies. The Company continues to focus significant research and development efforts to expand its MAS product platform and advance the applications of its unique technology into procedurally integrated surgical solutions. The Company dedicates significant resources toward training spine surgeons on its unique technology and products.
	The Company’s primary business model is to loan its MAS systems to surgeons and hospitals who purchase disposables and implants for use in individual procedures. In addition, for larger customers, the Company’s proprietary nerve monitoring systems, MaXcess and surgical instrument sets are placed with hospitals for an extended period at no up-front cost to them. The Company also offers a range of bone allograft in patented saline packaging, disposables and spine implants, which include its branded CoRoent® products and fixation devices such as rods, plates and screws. Implants and disposables are shipped from the Company’s inventories. The Company sells an immaterial quantity of MAS instrument sets, MaXcess and nerve monitoring systems to hospitals.
	Basis of Presentation and Principles of Consolidation.    The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Pursuant to these rules and regulations, the Company has condensed or omitted certain information and footnote disclosures it normally includes in its annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States (GAAP). In the opinion of management, the condensed consolidated financial statements include all adjustments necessary, which are of a normal and recurring nature, for the fair presentation of the Company's financial position and of the results of operations and cash flows for the periods presented.
	The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. Additionally, the unaudited condensed consolidated financial statements for all periods presented include the accounts of a variable interest entity, Progentix Orthobiology, B.V. (Progentix), which is consolidated pursuant to existing guidance issued by the Financial Accounting Standards Board (FASB).
	As a result of the 2011 acquisition of Impulse Monitoring Inc. (Impulse Monitoring), the Company maintains a contractual relationship with several physician practices (PCs) whereby the PCs provide the physician oversight service associated with the IOM services. Pursuant to such contractual arrangements, the Company provides management services to the PCs. As of September 30, 2013 and December 31, 2012, the associated PCs are American Neuromonitoring Associates, P.C.; Pacific Neuromonitoring Associates, Inc.; Keystone Neuromonitoring Associates, P.C.; North Pacific Neuromonitoring Associates, P.C.; and Midwest Neuromonitoring Associates, Inc. Under the management services agreements, the Company provides all non-medical services to the PCs in return for a management fee that is settled on a monthly basis. The management services include management reporting, billing and collections of all charges for medical services provided and all administrative support to the PCs. Pursuant to existing guidance issued by the FASB, these represent variable interest entities for which the Company is the primary beneficiary, and the accompanying consolidated financial statements include the accounts of the PCs from the date of acquisition.
	All significant intercompany balances and transactions have been eliminated in consolidation.
	These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2012 included in NuVasive's Annual Report on Form 10-K filed with the SEC. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for any other interim period or for the full year. The balance sheet at December 31, 2012 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by GAAP for complete financial statements.
	Reclassifications.    Certain reclassifications have been made to the prior period condensed consolidated financial statements and notes to conform to the current year presentation.

Recently_Adopted_Accounting_St

Recently Adopted Accounting Standards	9 Months Ended
	Sep. 30, 2013
New Accounting Pronouncements [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards
	Effective January 1, 2013, the Company adopted the FASB's requirements for presentation of reclassifications out of accumulated other comprehensive income (AOCI). The guidance requires companies to report, in one place, information about reclassifications out of AOCI and to present reclassifications by component when reporting changes in AOCI balances. The adoption of this authoritative guidance did not have an impact on the Company's financial position or results of operations.

Investment_in_Progentix_Orthob

Investment in Progentix Orthobiology, B.V.	9 Months Ended
	Sep. 30, 2013
Business Combination, Description [Abstract]
Investment in Progentix Orthobiology, B.V.	Investment in Progentix Orthobiology, B.V.
	In 2009, the Company completed the purchase of forty percent (40%) of the capital stock of Progentix, a company organized under the laws of the Netherlands, from existing shareholders (the Progentix Shareholders) pursuant to a Preferred Stock Purchase Agreement for $10 million in cash (the Initial Investment). Concurrent with the Initial Investment, NuVasive and Progentix also entered into a Senior Secured Facility Agreement, whereby Progentix may borrow up to $5.0 million from NuVasive to fund ongoing clinical and regulatory efforts (the Loan). At September 30, 2013, the Company had advanced Progentix the full $5.0 million in accordance with the Loan Agreement. The Loan accrues interest at a rate of six percent (6%) per year. Other than its obligations under the Loan Agreement, NuVasive is not obligated to provide additional funding, nor has any additional funding been provided, to Progentix.
	Also concurrent with the Preferred Stock Purchase Agreement, NuVasive, Progentix and the Progentix Shareholders entered into an Option Purchase Agreement, as amended (the Option Agreement), whereby NuVasive was obligated (the Put Option), upon the achievement of an annual sales run rate on Progentix products in excess of a specified amount between June 14, 2011 and June 13, 2013 (the Option Period), to purchase the remaining sixty percent (60%) of capital stock of Progentix from its shareholders (the Remaining Shares) for an amount up to $35.0 million, subject to certain reductions, payable in a combination of cash and NuVasive common stock, at NuVasive’s sole discretion. In accordance with the Option Agreement, NuVasive had the right to purchase the Remaining Shares (the Call Option) during the Option Period for an amount up to $35.0 million, subject to certain reductions, payable in a combination of cash and NuVasive common stock, at NuVasive’s sole discretion. The Option Agreement expired unexercised on June 13, 2013. NuVasive and Progentix also entered into a Distribution Agreement during 2009, as amended, whereby Progentix appointed NuVasive as its exclusive distributor for certain Progentix products. The Distribution Agreement will be in effect for a term of ten years unless terminated earlier in accordance with its terms.
	In accordance with authoritative guidance, the Company has determined that Progentix is a variable interest entity as it does not have the ability to finance its activities without additional subordinated financial support and its equity investors will not absorb their proportionate share of expected losses and will be limited in the receipt of the potential residual returns of Progentix. Additionally, pursuant to this guidance, NuVasive is considered its primary beneficiary as NuVasive has both (1) the power to direct the economically significant activities of Progentix and (2) the obligation to absorb losses of, or the right to receive benefits from, Progentix. Accordingly, the financial position and results of operations of Progentix have been included in the Company’s consolidated financial statements from the date of the Initial Investment. The liabilities recognized as a result of consolidating Progentix do not represent additional claims on the Company’s general assets. The creditors of Progentix have claims only on the assets of Progentix, which are not material, and the assets of Progentix are not available to NuVasive.
	Pursuant to authoritative guidance, the equity interests in Progentix not owned by the Company, which includes shares of both common and preferred stock, are reported as noncontrolling interests on the consolidated balance sheet of the Company. The preferred stock represents 18% of the noncontrolling equity interests and provides for a cumulative 8% dividend, if and when declared by Progentix’s Board of Directors. As the rights of the preferred stock are substantially the same as those of the common stock, the preferred stock is classified as noncontrolling interest and shares in the allocation of the losses incurred by Progentix. Losses incurred by Progentix are charged to the Company and to the noncontrolling interest holders based on their ownership percentage. The Remaining Shares and the Option Agreement that was entered into between NuVasive, Progentix and the Progentix Shareholders were not considered to be freestanding financial instruments during the Option Period as defined by authoritative guidance. Therefore, during the Option Period, the Remaining Shares and the Option Agreement were accounted for as a combined unit on the condensed consolidated financial statements as a redeemable noncontrolling interest that was initially recorded at fair value and classified as mezzanine equity. Upon the expiration of the Option Agreement on June 13, 2013, the noncontrolling interest was no longer redeemable and therefore, pursuant to the authoritative guidance, the noncontrolling interest was reclassified out of mezzanine equity to its own component of total equity within the Company's condensed consolidated balance sheet.
	Total assets and liabilities of Progentix included in the accompanying condensed consolidated balance sheet are as follows (in thousands):
		September 30, 2013		December 31, 2012
	Total current assets	$	523	$	657
	Identifiable intangible assets, net	14,520		14,871
	Goodwill	12,654		12,654
	Other long-term assets	9		15
	Accounts payable & accrued expenses	364		230
	Deferred tax liabilities, net	2,890		2,890
	Noncontrolling interests	9,258		10,003
	The following is a reconciliation of equity (net assets) attributable to the noncontrolling interests (in thousands):
		Nine Months Ended
		September 30,
		2013		2012
	Noncontrolling interests at beginning of period	$	10,003	$	10,705
	Less: Net loss attributable to the noncontrolling interests	745		672
	Noncontrolling interests at end of period	$	9,258	$	10,033

Balance_Sheet_Reserves

Balance Sheet Reserves	9 Months Ended
	Sep. 30, 2013
Valuation and Qualifying Accounts [Abstract]
Valuation Accounts	Balance Sheet Reserves
	The balances of the reserves for accounts receivable and inventory are as follows (in thousands):
		September 30, 2013		December 31, 2012
	Reserves for accounts receivable and sales returns	$	3,362	$	2,780
	Reserves for excess and obsolete inventory	$	18,722	$	16,856
	The Company's inventory consists primarily of purchased finished goods, which includes specialized implants and disposables, and is stated at the lower of cost or market determined by a weighted average cost method. The Company reviews the components of its inventory on a periodic basis for excess, obsolete or impaired inventory, and records a reserve for the identified items.

Marketable_Securities_and_Fair

Marketable Securities and Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Marketable Securities and Fair Value Measurements	Marketable Securities and Fair Value Measurements
	Marketable securities consist of certificates of deposit, corporate notes, commercial paper, U.S. government treasury securities and securities of government-sponsored entities. The Company classifies all securities as available-for-sale, as the sale of such securities may be required prior to maturity to implement management strategies. These securities are carried at fair value, with the unrealized gains and losses reported as a component of other comprehensive income in equity until realized. A decline in the market value of any marketable security below cost that is determined to be other-than-temporary will result in a revaluation of its carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. No such impairment charges were recorded for any period presented.
	Realized gains and losses from the sale of marketable securities, if any, are determined on a specific identification basis. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense on the consolidated statements of operations. Realized gains and losses during the periods presented were immaterial. Premiums and discounts are amortized or accreted over the life of the related security as an adjustment to yield using the straight-line method and are included in interest income on the condensed consolidated statements of operations. Interest and dividends on securities classified as available-for-sale are included in interest income on the condensed consolidated statements of operations.
	The composition of marketable securities is as follows (in thousands, except years):
		Contractual		Amortized Cost				Gross				Gross				Fair Value
		Maturity						Unrealized				Unrealized
		(in Years)						Gains				Losses
	September 30, 2013:
	Classified as current assets
	Certificates of deposit	Less than 1		$	1,099			$	—			$	—			$	1,099
	Corporate notes	Less than 1		58,787				23				(18		)		58,792
	Commercial paper	Less than 1		14,992				—				—				14,992
	U.S. government treasury securities	Less than 1		14,616				8				—				14,624
	Securities of government-sponsored entities	Less than 1		19,697				10				—				19,707
	Short-term marketable securities			109,191				41				(18		)		109,214
	Classified as non-current assets
	Certificates of deposit	1 to 2		575				—				—				575
	Corporate notes	1 to 2		26,332				15				(18		)		26,329
	U.S. government treasury securities	1 to 2		1,500				1				—				1,501
	Securities of government-sponsored entities	1 to 2		64,557				42				(5		)		64,594
	Long-term marketable securities			92,964				58				(23		)		92,999
	Classified as restricted investments
	U.S. government treasury securities	Less than 2		47,407				22				(2		)		47,427
	Securities of government-sponsored entities	Less than 2		39,149				9				(2		)		39,156
	Restricted investments			86,556				31				(4		)		86,583
	Total marketable securities at September 30, 2013			$	288,711			$	130			$	(45	)		$	288,796
	December 31, 2012:
	Classified as current assets
	Certificates of deposit	Less than 1		$	998			$	—			$	—			$	998
	Corporate notes	Less than 1		19,169				3				(1		)		19,171
	Commercial paper	Less than 1		9,995				2				—				9,997
	U.S. government treasury securities	Less than 1		17,055				6				—				17,061
	Securities of government-sponsored entities	Less than 1		91,151				27				—				91,178
	Short-term marketable securities			138,368				38				(1		)		138,405
	Classified as non-current assets
	Corporate notes	1 to 2		23,293				—				(17		)		23,276
	U.S. government treasury securities	1 to 2		7,619				4				—				7,623
	Securities of government-sponsored entities	1 to 2		53,493				22				(2		)		53,513
	Long-term marketable securities			84,405				26				(19		)		84,412
	Classified as restricted investments
	U.S. government treasury securities	Less than 2		31,784				5				(1		)		31,788
	Securities of government-sponsored entities	Less than 2		53,618				18				(1		)		53,635
	Restricted investments			85,402				23				(2		)		85,423
	Total marketable securities at December 31, 2012			$	308,175			$	87			$	(22	)		$	308,240
	As of September 30, 2013, the Company had no investments that were in a significant unrealized loss position. The Company reviews its investments to identify and evaluate investments that have an indication of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. The Company maintains an investment portfolio of various holdings, types and maturities. The Company does not hold derivative financial investments. The Company places its cash investments in instruments that meet high credit quality standards, as specified in its investment policy guidelines. These guidelines also limit the amount of credit exposure to any one issue, issuer or type of instrument.
	The Company measures certain assets and liabilities in accordance with authoritative guidance which requires fair value measurements be classified and disclosed in one of the following three categories:
	Level 1: Quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities.
	Level 2: Observable prices that are based on inputs not quoted on active markets, but corroborated by market data.
	Level 3: Unobservable inputs are used when little or no market data is available.
	Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels for certain assets or liabilities within the fair value hierarchy. The Company did not have any transfers of assets and liabilities between Level 1 and Level 2 of the fair value measurement hierarchy during the three and nine months ended September 30, 2013 and 2012. The Company had no transfers from Level 3 of the fair value measurement hierarchy during the three and nine months ended September 30, 2013 and the three months ended September 30, 2012. The Company had one transfer from Level 3 of the fair value measurement hierarchy during the nine months ended September 30, 2012, as a result of the settlement of a milestone.
	The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):
		Total				Quoted Price in				Significant Other				Significant
						Active Market				Observable Inputs				Unobservable
						(Level 1)				(Level 2)				Inputs (Level 3)
	September 30, 2013:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	59,107			$	59,107			$	—			$	—
	Certificates of deposit	1,674				1,674				—				—
	Corporate notes	85,121				—				85,121				—
	Commercial paper	14,992				—				14,992				—
	U.S. government treasury securities	63,552				63,552				—				—
	Securities of government-sponsored entities	123,457				—				123,457				—
	Total cash equivalents, marketable securities and restricted investments	$	347,903			$	124,333			$	223,570			$	—
	Contingent Consideration:
Acquisition-related liabilities, current	$	(573	)		$	—			$	—			$	(573	)
Acquisition-related liabilities, non-current	$	(576	)		$	—			$	—			$	(576	)
Total contingent consideration	$	(1,149	)		$	—			$	—			$	(1,149	)
December 31, 2012:
Cash Equivalents, Marketable Securities and Restricted Investments:
Money market funds	$	89,101			$	89,101			$	—			$	—
Certificates of deposit	998				998				—				—
Corporate notes	42,447				—				42,447				—
Commercial paper	9,997				—				9,997				—
U.S. government treasury securities	56,472				56,472				—				—
Securities of government-sponsored entities	198,326				—				198,326				—
Total cash equivalents, marketable securities and restricted investments	$	397,341			$	146,571			$	250,770			$	—
Contingent Consideration:
Acquisition-related liabilities, non-current	$	(1,074	)		$	—			$	—			$	(1,074	)
The carrying amounts of financial instruments such as cash equivalents, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses, and other current liabilities approximate the related fair values due to the short-term maturities of these instruments. The estimated fair value of the Company's capital lease obligations approximated their carrying values as of September 30, 2013 and December 31, 2012. The fair and carrying value of the Company’s Senior Convertible Notes is discussed in Note 7.
Contingent Consideration Liability
In connection with the acquisition of Cervitech, Inc. (Cervitech) in May 2009, the Company was required to pay an additional amount not to exceed $33.0 million in the event that the PCM Cervical Disc System (PCM) received FDA approval. The fair value of the contingent consideration was determined using a probability-weighted discounted cash flow model, the significant inputs of which were not observable in the market. The key assumptions in applying this approach were the interest rate, the timing of expected approval and the probability assigned to the milestone being achieved. During the fourth quarter of 2012, the PCM was approved by the FDA. Accordingly, the contingent consideration liability was accreted to $33.0 million. Changes in fair value were recorded in the statement of operations as sales, marketing and administrative expenses.
In connection with an immaterial acquisition in 2012, the Company is required to pay an amount not to exceed €2.0 million in the event two specified revenue-based milestones are met. The fair value of the contingent consideration was determined using a discounted cash flow model, the significant inputs of which are not observable in the market. The key assumptions in applying this approach are the revenue projections, the interest rate and the probabilities assigned to the milestones being achieved. Based on these assumptions, the estimated fair value of the contingent consideration totaled $1.1 million at September 30, 2013 and is included in accrued liabilities in the September 30, 2013 condensed consolidated balance sheet. Changes in fair value are recorded in the statements of operations as sales, marketing and administrative expenses.
In addition, during the nine months ended September 30, 2012, approximately $0.5 million related to contingent consideration recorded in connection with an immaterial acquisition which occurred in 2010 was settled and no longer considered contingent consideration.
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):
	Nine Months Ended September 30,
	2013				2012
Fair value measurement at beginning of period	$	1,074			$	32,221
Contingent consideration liability recorded upon acquisition	—				1,019
Change in fair value measurement included in operating expenses	75				708
Contingent consideration settled	—				(530		)
Fair value measurement at end of period	$	1,149			$	33,418

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets
	Goodwill and intangible assets consisted of the following (in thousands, except years):
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	September 30, 2013:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	56,328	$	(19,668	)	$	36,660
	Manufacturing know-how and trade secrets	12		21,979		(9,412		)	12,567
	Trade name and trademarks	11		9,500		(3,071		)	6,429
	Customer relationships	8		43,865		(17,124		)	26,741
		10		$	131,672	$	(49,275	)	$	82,397
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,913
	Total goodwill and intangible assets, net								$	247,950
		Weighted-		Gross		Accumulated			Intangible
		Average		Amount		Amortization			Assets, net
		Amortization
		Period
		(in years)
	December 31, 2012:
	Intangible Assets Subject to Amortization:
	Purchased technology:
	Developed technology	10		$	55,178	$	(14,966	)	$	40,212
	Manufacturing know-how and trade secrets	12		21,712		(7,996		)	13,716
	Trade name and trademarks	11		9,500		(2,333		)	7,167
	Customer relationships	9		39,330		(9,703		)	29,627
		10		$	125,720	$	(34,998	)	$	90,722
	Intangible Assets Not Subject to Amortization:
	In-process research and development								10,640
	Goodwill								154,106
	Total goodwill and intangible assets, net								$	255,468
	Total expense related to the amortization of intangible assets was $5.0 million and $3.1 million for the three months ended September 30, 2013 and 2012, respectively, and $14.3 million and $8.8 million for the nine months ended September 30, 2013 and 2012, respectively. In-process research and development will be amortized beginning on the regulatory approval date of the respective acquired products and will be amortized over the estimated useful life determined at that time.
	Total future amortization expense related to intangible assets subject to amortization at September 30, 2013 is set forth in the table below (in thousands):
	Remaining 2013	$	4,971
	2014	13,603
	2015	12,515
	2016	12,040
	2017	9,688
	2018	9,171
	Thereafter through 2026	20,409
	Total future amortization expense	$	82,397

Senior_Convertible_Notes

Senior Convertible Notes	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Senior Convertible Notes	Senior Convertible Notes
	The carrying values of the Company’s Senior Convertible Notes are as follows (in thousands):
		September 30, 2013			December 31, 2012
	2.75% Senior Convertible Notes due 2017:
	Principal amount	$	402,500		$	402,500
	Unamortized debt discount	(59,948		)	(70,096		)
		342,552			332,404
	2.25% Senior Convertible Notes due 2013	—			74,311
	Total Senior Convertible Notes	$	342,552		$	406,715
	2.75% Senior Convertible Notes due 2017
	In June 2011, the Company issued $402.5 million principal amount of the 2017 Notes, which includes the issuance of $52.5 million principal amount for the exercise of the initial purchasers’ option to purchase additional notes. The net proceeds from the offering, after deducting initial purchasers’ discounts and costs directly related to the offering, were approximately $359.2 million. The 2017 Notes have a stated interest rate of 2.75% and mature on July 1, 2017. Prior to September 28, 2011, the date on which stockholder approval to increase the number of the Company’s authorized shares of common stock from 70 million to 120 million was obtained, the 2017 Notes were settleable only in cash. Subsequent to the receipt of this approval, the 2017 Notes may be settled in cash, stock, or a combination thereof, solely at the Company’s election. It is the Company’s current intent and policy to settle all conversions through combination settlement, which involves repayment of an amount of cash equal to the principal amount and any excess of the conversion value over the principal amount in shares of common stock. The initial conversion rate of the 2017 Notes is 23.7344 shares per $1,000 principal amount, subject to adjustment (which represents an initial conversion price of approximately $42.13 per share).
	Interest on the 2017 Notes began accruing in June 2011 and is payable semi-annually each January 1st and July 1st, beginning January 1, 2012. The fair value, based on a quoted market price, or Level 1, of the outstanding 2017 Notes at September 30, 2013 and December 31, 2012 was approximately $392.8 million and $361.3 million, respectively.
	Prior to January 1, 2017, holders may convert their 2017 Notes only under the following conditions: a) During any calendar quarter beginning October 1, 2011, if the reported sale price of the Company’s common stock for at least 20 days of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than 130% of the conversion price on each applicable trading day; b) During the five business day period in which the trading price of the 2017 Notes falls below 98% of the product of (i) the last reported sale price of the Company’s common stock and (ii) the conversion rate on that date; and c) Upon the occurrence of specified corporate events, as defined in the 2017 Notes. From January 1, 2017 and until the close of business on the second scheduled trading day immediately preceding July 1, 2017, holders may convert their 2017 Notes at any time, regardless of the foregoing circumstances. The Company may not redeem the 2017 Notes prior to maturity. As of September 30, 2013, the “if-converted” value of the 2017 Notes did not exceed its principal amount and none of the conditions allowing holders of the 2017 Notes to convert had been met.
	Other than restrictions relating to certain fundamental changes and consolidations, mergers or asset sales and customary anti-dilution adjustments, the 2017 Notes do not contain any financial covenants and do not restrict the Company from paying dividends or issuing or repurchasing any of its other securities.
	In accordance with authoritative guidance, the cash conversion feature of the 2017 Notes (the 2017 Notes Embedded Conversion Derivative) required bifurcation from the 2017 Notes and was initially accounted for as a derivative liability. The fair value of the 2017 Notes Embedded Conversion Derivative at the time of issuance of the 2017 Notes was $88.9 million, and was recorded as the original debt discount for purposes of accounting for the debt component of the 2017 Notes. On September 28, 2011, upon obtaining stockholder approval of the additional authorized shares of the Company’s common stock, in accordance with authoritative literature, the derivative liability was marked to fair value and reclassified to equity. The original debt discount is being recognized as interest expense using an effective interest rate of 8.0% over the term of the 2017 Notes. At September 30, 2013 and December 31, 2012, the net carrying value of the equity component is $49.3 million.
	The interest expense recognized on the 2017 Notes during the three months ended September 30, 2013 includes $2.8 million and $3.4 million for the contractual coupon interest and the accretion of the debt discount, respectively. The interest expense recognized on the 2017 Notes during the nine months ended September 30, 2013 includes $8.3 million and $10.1 million for the contractual coupon interest and the accretion of the debt discount, respectively. During the three months ended September 30, 2012, interest expense recognized on the 2017 Notes includes $2.8 million and $3.2 million for the contractual coupon interest and the accretion of the debt discount, respectively. The interest expense recognized on the 2017 Notes during the nine months ended September 30, 2012 includes $8.3 million and $9.4 million for the contractual coupon interest and the accretion of the debt discount, respectively.
	In connection with the offering of the 2017 Notes, the Company entered into a convertible note hedge transaction (the 2017 Hedge) with the initial purchasers and/or their affiliates (the 2017 Counterparties) entitling the Company to purchase up to 9,553,096 shares of the Company’s common stock at an initial stock price of $42.13 per share, each of which is subject to adjustment. Prior to obtaining the stockholder approval to increase the number of the Company’s authorized common shares discussed above, the 2017 Hedge was settleable only in cash and was accounted for as a derivative asset. The cost of the 2017 Hedge was $80.1 million. On September 28, 2011, upon obtaining stockholder approval of the additional authorized shares of the Company’s common stock, in accordance with authoritative literature, the derivative asset was marked to fair value and reclassified to stockholders’ equity. The 2017 Hedge expires on July 1, 2017. The 2017 Hedge is expected to reduce the potential equity dilution upon conversion of the 2017 Notes if the daily volume-weighted average price per share of the Company’s common stock exceeds the strike price of the 2017 Hedge.
	In addition, the Company sold warrants to the 2017 Counterparties to acquire up to 477,654 shares of the Company’s Series A Participating Preferred Stock (the 2017 Warrants), at an initial strike price of $988.51 per share, subject to adjustment. Each share of Series A Participating Preferred Stock is initially convertible into 20 shares of the Company’s common stock. The 2017 Warrants expire on various dates from September 2017 through January 2018 and may be settled in cash or net shares. The Company received $47.9 million in cash proceeds from the sale of the 2017 Warrants, which has been recorded as an increase in additional paid-in-capital. The 2017 Warrants could have a dilutive effect on the Company’s earnings per share to the extent that the price of the Company’s common stock during a given measurement period (the quarter or year-to-date period) exceeds the strike price of the 2017 Warrants.
	2.25% Senior Convertible Notes due 2013
	In March 2008, the Company issued $230.0 million principal amount of 2.25% unsecured Senior Convertible Notes (the 2013 Notes). The net proceeds from the offering, after deducting the initial purchasers’ discounts and costs directly related to the offering, were approximately $208.4 million. During the year ended December 31, 2011, the Company repurchased, in privately negotiated transactions, approximately $155.7 million in principal of its 2013 Notes. The remaining balance of the 2013 Notes matured on March 15, 2013 and accordingly, during the three months ended March 31, 2013, the Company repaid the total outstanding principal amount of $74.3 million in cash.
	In connection with the offering of the 2013 Notes, the Company sold to the initial purchasers and/or their affiliates warrants to acquire up to 5.1 million shares of the Company's common stock (the 2013 Warrants), at an initial strike price of $49.13 per share, subject to adjustment. The 2013 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 (the quarter or year to date period) exceeds the strike price of the 2013 Warrants. The 2013 Warrants began expiring in June 2013 and at September 30, 2013, warrants to acquire up to 0.4 million shares of the Company's common stock remained outstanding. All remaining outstanding warrants expired on or before October 8, 2013.

Net_Income_Per_Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
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 restricted stock units, including those with performance and market conditions, warrants, and the shares to be issued upon the conversion of the Senior Convertible Notes. No shares related to the assumed exercise of outstanding warrants or the conversion of the Senior Convertible Notes were included in the diluted net income per share calculation for the three and nine months ended September 30, 2013 and 2012 because the inclusion of such shares would have had an anti-dilutive effect.
	The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
	Numerator:
	Net income attributable to NuVasive, Inc.	$	7,511		$	2,354		$	1,893	$	5,890
	Denominator for basic and diluted net income per share:
	Weighted average common shares outstanding for basic	44,572			43,488			44,339		43,227
	Dilutive potential common stock outstanding:
	Stock options and Employee Stock Purchase Plan (ESPP)	473			317			304		215
	Restricted stock units	2,175			930			1,744		709
	Weighted average common shares outstanding for diluted	47,220			44,735			46,387		44,151
	Basic net income per share attributable to NuVasive, Inc.	$	0.17		$	0.05		$	0.04	$	0.14
	Diluted net income per share attributable to NuVasive, Inc.	$	0.16		$	0.05		$	0.04	$	0.13
	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 (in thousands):
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Stock options, ESPP shares and unvested restricted stock units	4,957		5,921			5,759		6,047
	Warrants	11,998		14,694			13,768		14,694
	Senior Convertible Notes	9,553		11,214			10,003		11,214
	Total	26,508		31,829			29,530		31,955

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation
	The Company estimates the fair value of stock options and shares issued to employees under the ESPP using a Black-Scholes option-pricing model on the date of grant. The fair value of restricted stock units is based on the stock price on the date of grant. The fair value of equity instruments that are expected to vest are recognized and amortized on an accelerated basis over the requisite service period.
	The weighted average assumptions used to estimate the fair value of stock purchase rights under the ESPP are as follows:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013			2012
	ESPP
	Volatility	57	%	55	%		57	%		55	%
	Expected term (years)	1.7		1.6			1.6			1.5
	Risk free interest rate	0.2	%	0.2	%		0.2	%		0.2	%
	Expected dividend yield	—	%	—	%		—	%		—	%
	The Company did not grant any stock options during the three or nine months ended September 30, 2013 or 2012.
	The Company issued 24,000 and 29,000 shares of common stock upon the exercise of stock options during the three and nine months ended September 30, 2013, respectively, and issued 48,000 shares of common stock upon the exercise of stock options during the year ended December 31, 2012. The Company issued 70,000 and 510,000 shares of common stock upon the vesting of RSUs during the three and nine months ended September 30, 2013, respectively, and issued 339,000 shares of common stock upon the vesting of RSUs during the year ended December 31, 2012.
	In 2012, the Compensation Committee of the Board of Directors (the Compensation Committee) granted performance-based restricted stock units (PRSUs) to certain senior Company executives that were earned based on the achievement of pre-defined Company-specific performance criteria for the year ended December 31, 2012. The fair value of the PRSUs was based on the closing price of the Company's common stock on the date of grant. One-third of the PRSUs vested on March 1, 2013 and the remaining two-thirds vest equally on March 1, 2014 and March 1, 2015. The Company issued 117,000 shares of common stock upon the vesting of PRSUs during the three months ended March 31, 2013.
	During the first quarter of 2013, the Compensation Committee granted restricted stock units to certain senior Company executives that are earned based on the achievement of pre-defined market conditions (total stockholder return) for the year ended December 31, 2013 (TSR PRSUs). The fair value of the TSR PRSUs was estimated on the date of grant using a Monte Carlo valuation model. The key assumptions in applying this model are an expected volatility of 49% and a risk free interest rate of 0.13%. The TSR PRSUs vest in two equal installments on February 1, 2014 and February 1, 2015.
	The compensation cost that has been included in the statement of operations for all stock-based compensation arrangements was as follows (in thousands):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013			2012				2013			2012
	Sales, marketing and administrative expense	$	7,965		$	4,844			$	22,667		$	18,723
	Research and development expense	448			567				1,239			1,624
	Cost of goods sold	41			23				96			53
	Total stock-based compensation expense	$	8,454		$	5,434			$	24,002		$	20,400

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The Company recorded income tax expense of $0.9 million and $4.1 million for the three months ended September 30, 2013 and 2012, respectively, and an income tax expense of $20 thousand and $7.8 million for the nine months ended September 30, 2013 and 2012, respectively. The effective income tax rate for the nine months ended September 30, 2013 was 2%, and reflected a discrete tax benefit of $0.9 million, or 77% of pre-tax income, related to the 2012 federal research and development (R&D) credit which was retrospectively reinstated in the nine months ended September 30, 2013. The Company updates its annual effective income tax rate each quarter and if the estimated effective income tax rate changes, a cumulative adjustment is made.
	There were no material changes to the Company's unrecognized tax benefits and interest accrued related to unrecognized tax benefits during the nine months ended September 30, 2013.

Business_Segment_Product_and_G

Business Segment, Product, and Geographic Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Business Segment and Product Information	Business Segment, Product and Geographic Information
	The Company’s business operates in one segment based upon the Company’s organizational structure, the way in which the operations are managed and evaluated and the lack of availability of separate financial results.
	The Company’s Spine Surgery Product line offerings, which include thoracolumbar product offerings, cervical offerings, and a set of motion preservation products still under development, are primarily used to enable access to the spine and to perform restorative and fusion procedures in a minimally disruptive fashion. The Company’s Biologic product line offerings includes allograft (donated human tissue), FormaGraft®, a collagen synthetic product, Osteocel Plus®, an allograft cellular matrix containing viable mesenchymal stem cells, or MSCs, and AttraX®, a synthetic bone graft material, all used to aid the spinal fusion process. The Company’s Monitoring Service offering includes IOM services. Revenue by product line offerings was as follows (in thousands):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
	Spine Surgery Products	$	131,137	$	112,590	$	382,485	$	343,962
	Biologics	28,743		26,158		83,754		81,256
	Monitoring Service	9,276		9,643		28,119		29,283
	Total Revenue	$	169,156	$	148,391	$	494,358	$	454,501
	Revenue and property and equipment, net, by geographic area were as follows (in thousands):
		Revenue								Property and Equipment, Net
		Three Months Ended				Nine Months Ended				As of September 30,		As of December 31,
		September 30,				September 30,
		2013		2012		2013		2012		2013		2012
	United States	$	152,377	$	136,885	$	450,024	$	422,754	$	112,976	$	112,701
	International (excludes Puerto Rico)	16,779		11,506		44,334		31,747		17,820		12,422
	Total	$	169,156	$	148,391	$	494,358	$	454,501	$	130,796	$	125,123

Legal_Proceedings

Legal Proceedings	9 Months Ended
	Sep. 30, 2013
Legal Proceedings [Abstract]
Legal Proceedings	Legal Proceedings
	Medtronic Sofamor Danek USA, Inc. Litigation
	In August 2008, Warsaw Orthopedic, Inc., Medtronic Sofamor Danek USA, Inc. and other Medtronic related entities (collectively, Medtronic) filed suit against NuVasive in the U.S. District Court for the Southern District of California (the Medtronic Litigation), alleging that certain of NuVasive’s products infringe, or contribute to the infringement of, twelve U.S. patents assigned or licensed to Medtronic. Three of the patents were later withdrawn by Medtronic, leaving nine patents. NuVasive brought counterclaims against Medtronic alleging infringement of certain of NuVasive’s patents. The case has been administratively broken into serial phases. The first phase of the case included three Medtronic patents and one NuVasive patent and on September 20, 2011, a jury from the U.S. District Court delivered an unfavorable verdict against NuVasive with respect to the three Medtronic patents and a favorable verdict with respect to the one NuVasive patent. The jury awarded monetary damages of approximately $101.2 million to Medtronic, which includes lost profits and back royalties (the 2011 verdict). Medtronic’s subsequent motion for a permanent injunction was denied by the District Court on January 26, 2012. The District Court entered judgment on March 2, 2012. Both parties appealed the verdict. Medtronic subsequently filed a motion to dismiss its own appeal and NuVasive's cross-appeal with the Federal Circuit Court of Appeals. On August 2, 2012, the Federal Circuit issued a ruling stating that ongoing royalties must be determined by the District Court prior to the appeal going forward. On June 11, 2013, the District Court ruled on the ongoing royalty rates (the June 2013 ruling). On August 20, 2013, NuVasive and Medtronic filed their respective notices of appeal, and the appeal is now proceeding before the U.S. Court of Appeals for the Federal Circuit. In addition, on March 19, 2012, the District Court issued an order granting prejudgment interest. The Company entered into an escrow arrangement in 2012 and transferred $113.3 million of cash into a restricted escrow account to secure the amount of judgment, plus prejudgment interest, during pendency of the appeal. These funds are included in restricted cash and investments on the Company's September 30, 2013 condensed consolidated balance sheet.
	In accordance with the authoritative guidance on the evaluation of loss contingencies, during the year ended December 31, 2011, the Company recorded an accrual of $101.2 million for the 2011 verdict. In addition, on sales subsequent to the 2011 verdict and through March 31, 2013, the Company accrued royalties at the royalty rates stated in the 2011 verdict. Upon receiving the District Court ruling in June 2013, the Company began accruing ongoing royalties on sales at the royalty rates stated in the June 2013 ruling, and recorded a charge of approximately $7.9 million to account for the difference between using the royalty rates stated in the 2011 verdict and those in the June 2013 ruling on sales through March 31, 2013. As a result of the June 2013 ruling, the Company will be required to escrow funds to secure accrued royalties, estimated at $21 million to date, and ongoing royalties. The Company is also accruing post-judgment interest. With respect to the prejudgment interest award, the Company, based on its own assessment, as well as that of outside counsel, believes a reversal of the prejudgment interest award on appeal is probable, and therefore, in accordance with authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual for this amount, which is estimated to approximate $13 million. Additional damages, including interest may still be awarded, and at September 30, 2013, the Company cannot estimate a range of additional potential loss.
	With respect to the favorable verdict delivered regarding the one NuVasive patent, the jury awarded the Company monetary damages of approximately $0.7 million for reasonable royalty damages. In accordance with the authoritative guidance on the evaluation of gain contingencies, this amount has not been recorded at September 30, 2013. Additionally, the June 2013 ruling determined the ongoing royalty rate to be paid to the Company by Medtronic for its post-verdict sales of the one NuVasive patent. Consistent with the treatment afforded the $0.7 million damage award; no amount has been recorded for royalty revenue as of September 30, 2013.
	The second phase of the case pending in the Southern District of California involved one Medtronic cervical plate patent. On April 25, 2013, NuVasive and Medtronic entered into a settlement agreement fully resolving the second phase of the case. The settlement also removes from the case the cervical plate patent that was part of the first phase. As part of the settlement, NuVasive received a broad license to practice (i) the Medtronic patent that was the sole subject of the second phase of the litigation, (ii) the Medtronic patent that was part of the first phase of the litigation, and (iii) each of the Medtronic patent families that collectively represent the vast majority of Medtronic's patent rights related to cervical plate technology. In exchange for these license rights, NuVasive made a one-time payment to Medtronic of $7.5 million, which amount will be fully offset against any damage award ultimately determined to be owed by NuVasive in connection with a final resolution of the first phase of the litigation. In addition, Medtronic will receive a royalty on certain cervical plate products sold by NuVasive, including the Helix® and Gradient® lines of products. As a result of this settlement, all current patent disputes between the parties related to cervical plate technology have been resolved.
	On August 17, 2012, Medtronic filed additional patent claims in the U.S. District Court for the Northern District of Indiana alleging that various NuVasive spinal implants (including its CoRoent® XL family of spinal implants) and NuVasive's Osteocel® Plus bone graft product infringe two additional Medtronic Patents not asserted in the Southern District of California. On August 28, 2012, Medtronic amended its complaint alleging that NuVasive's XLIF procedure and use of MaXcess IV retractor during the XLIF procedure infringe methodology claims of another Medtronic patent. The Company denies infringing any valid claims of these additional patents and on September 4, 2012, the Company filed a motion to transfer the case to the Southern District of California. The Indiana District Court granted the Company's motion and transferred the case to the Southern District of California.
	On March 7, 2013, NuVasive amended its counterclaims to allege infringement by Medtronic of eight NuVasive patents not asserted in the first or second phases of the litigation. On March 22, 2013, NuVasive moved to stay the litigation of two of Medtronic's patents pending the U.S. Patent Office proceedings with respect to these patents. The Court granted the Company's motion with respect to one of the patents, and denied without prejudice to renew the motion with respect to the second patent. On September 23, 2013, the U.S. Patent Office granted inter partes review of the second patent. The Court granted the Company's motion with respect to one of the patents, and denied without prejudice to renew the motion with respect to the second patent. On June 27, 2013, NuVasive filed an inter partes review petition with the U.S. Patent Office challenging a third patent that issued to Medtronic on May 21, 2013. On July 25, 2013, the Court granted Medtronic leave to amend the complaint to add a charge of infringement of the third patent. On September 23, 2013, the U.S. Patent Office granted inter partes review of the second patent. Based on the U.S. Patent Office's grant of inter partes review, the Company intends to renew its motion to stay the second patent. On July 25, 2013, the Court granted Medtronic leave to amend the complaint to add a charge of infringement of U.S. Patent No. 8,444,696. A claim construction hearing is scheduled for November 7, 2013 and a pre-trial conference for June 20, 2014. No trial date is set. At September 30, 2013, the probable outcome of this litigation cannot be determined, nor can the Company estimate a range of potential loss. In accordance with the authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual related to this litigation.
	Trademark Infringement Litigation
	In September 2009, Neurovision Medical Products, Inc. (NMP) filed suit against NuVasive in the U.S. District Court for the Central District of California (Case No. 2:9-cv-6988-R-JEM) alleging trademark infringement and unfair competition. NMP sought cancellation of NuVasive’s “NeuroVision” trademark registrations, injunctive relief and damages based on NMP’s common law use of the “Neurovision” mark. On November 23, 2009, the Company denied the allegations in NMP’s complaint. The matter was tried in October 2010 and an unfavorable jury verdict was delivered against the Company relating to its use of the NeuroVision trade name. The verdict awarded damages to NMP of $60.0 million. The Company appealed the judgment and on September 10, 2012, the Court of Appeals reversed and vacated the District Court judgment and ordered the case back to the District Court for a new trial before a different judge. On October 5, 2012, the case was reassigned to a new District Court judge and re-trial of the matter is currently scheduled to begin in the District Court in January 2014. During pendency of the appeal, the Company was required to escrow funds totaling $62.5 million to secure the amount of the judgment, plus interest, attorneys’ fees and costs. As a result of the reversal of the judgment, the full $62.5 million was released from escrow and returned to the Company. At September 30, 2013, the probable outcome of this litigation cannot be determined, nor can the Company estimate a range of potential loss. In accordance with the authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual related to this litigation.
	Securities Litigation
	On August 28, 2013, a purported securities class action lawsuit was filed by Danny Popov in the United States District Court for the Southern District of California naming NuVasive and certain of its current and former executive officers for allegedly making false and materially misleading statements regarding the Company's business and financial results, specifically relating to the purported improper submission of false claims to Medicare and Medicaid. The complaint asserts a putative class period stemming from October 22, 2008 to July 30, 2013. The complaint alleges violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 promulgated thereunder and seeks unspecified monetary relief, interest, and attorneys’ fees. The Company intends to vigorously defend against this action. At September 30, 2013, the probable outcome of this litigation cannot be determined, nor can the Company estimate a range of potential loss. In accordance with authoritative guidance on the evaluation of loss contingencies, the Company has not recorded an accrual related to this litigation.
	Contingencies
	The Company is party to certain claims and legal actions arising in the normal course of business. The Company does not expect any such claims and legal actions to have a material adverse effect on its business, results of operations or financial condition.

Regulatory_Matter_Notes

Regulatory Matter (Notes)	9 Months Ended
	Sep. 30, 2013
Regulatory Matter [Abstract]
Regulatory Matter [Text Block]	13.    Regulatory Matter
	During the three months ended June 30, 2013, the Company received a federal administrative subpoena from the Office of the Inspector General of the U.S. Department of Health and Human Services (OIG) in connection with an investigation into possible false or otherwise improper claims submitted to Medicare and Medicaid. The subpoena seeks discovery of documents for the period January 2007 through April 2013. The Company is working with the OIG to understand the scope of the subpoena and its request for documents, but does not expect to have greater clarity regarding the request for several months. The Company intends to fully cooperate with the OIG's request. At September 30 2013, the Company is unable to determine the potential financial impact, if any, that will result from this investigation.

Description_of_Business_and_Ba1

Description of Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business.    NuVasive, Inc. (the Company or NuVasive) was incorporated in Delaware on July 21, 1997, and began commercializing its products in 2001. The Company is focused on developing minimally disruptive surgical products and procedurally integrated solutions for the spine. NuVasive's principal product offering includes a minimally disruptive surgical platform called Maximum Access Surgery, or MAS®, as well as an offering of biologics, cervical and motion preservation products. The MAS platform combines three categories of solutions that collectively minimize soft tissue disruption during spine fusion surgery, provide maximum visualization and are designed to enable reproducible outcomes for the surgeon. The platform includes a proprietary software-driven nerve detection and avoidance systems, NVM5 and NVJJB, and Intra-Operative Monitoring (IOM) support; MaXcess®, a unique and integrated split-blade retractor system; and a wide variety of specialized implants. When the three elements of MAS are used together, they may significantly reduce surgery time and return patients to activities of daily living much faster than conventional approaches. The individual components of NuVasive's MAS platform, and many of the Company's products, can also be used in open or traditional spine surgery and may independently offer patient benefits to various surgical approaches dealing with a wide variety of pathologies. The Company continues to focus significant research and development efforts to expand its MAS product platform and advance the applications of its unique technology into procedurally integrated surgical solutions. The Company dedicates significant resources toward training spine surgeons on its unique technology and products.
	The Company’s primary business model is to loan its MAS systems to surgeons and hospitals who purchase disposables and implants for use in individual procedures. In addition, for larger customers, the Company’s proprietary nerve monitoring systems, MaXcess and surgical instrument sets are placed with hospitals for an extended period at no up-front cost to them. The Company also offers a range of bone allograft in patented saline packaging, disposables and spine implants, which include its branded CoRoent® products and fixation devices such as rods, plates and screws. Implants and disposables are shipped from the Company’s inventories. The Company sells an immaterial quantity of MAS instrument sets, MaXcess and nerve monitoring systems to hospitals.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation.    The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Pursuant to these rules and regulations, the Company has condensed or omitted certain information and footnote disclosures it normally includes in its annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States (GAAP). In the opinion of management, the condensed consolidated financial statements include all adjustments necessary, which are of a normal and recurring nature, for the fair presentation of the Company's financial position and of the results of operations and cash flows for the periods presented.
	The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. Additionally, the unaudited condensed consolidated financial statements for all periods presented include the accounts of a variable interest entity, Progentix Orthobiology, B.V. (Progentix), which is consolidated pursuant to existing guidance issued by the Financial Accounting Standards Board (FASB).
	As a result of the 2011 acquisition of Impulse Monitoring Inc. (Impulse Monitoring), the Company maintains a contractual relationship with several physician practices (PCs) whereby the PCs provide the physician oversight service associated with the IOM services. Pursuant to such contractual arrangements, the Company provides management services to the PCs. As of September 30, 2013 and December 31, 2012, the associated PCs are American Neuromonitoring Associates, P.C.; Pacific Neuromonitoring Associates, Inc.; Keystone Neuromonitoring Associates, P.C.; North Pacific Neuromonitoring Associates, P.C.; and Midwest Neuromonitoring Associates, Inc. Under the management services agreements, the Company provides all non-medical services to the PCs in return for a management fee that is settled on a monthly basis. The management services include management reporting, billing and collections of all charges for medical services provided and all administrative support to the PCs. Pursuant to existing guidance issued by the FASB, these represent variable interest entities for which the Company is the primary beneficiary, and the accompanying consolidated financial statements include the accounts of the PCs from the date of acquisition.
	All significant intercompany balances and transactions have been eliminated in consolidation.
	These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2012 included in NuVasive's Annual Report on Form 10-K filed with the SEC. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for any other interim period or for the full year. The balance sheet at December 31, 2012 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by GAAP for complete financial statements.
Reclassifications and Adjustments	Reclassifications.    Certain reclassifications have been made to the prior period condensed consolidated financial statements and notes to conform to the current year presentation.

Investment_in_Progentix_Orthob1

Investment in Progentix Orthobiology, B.V. (Tables)	9 Months Ended
	Sep. 30, 2013
Business Combination, Description [Abstract]
Summary of assets and liabilities included in the accompanying consolidated balance sheet	Total assets and liabilities of Progentix included in the accompanying condensed consolidated balance sheet are as follows (in thousands):
		September 30, 2013		December 31, 2012
	Total current assets	$	523	$	657
	Identifiable intangible assets, net	14,520		14,871
	Goodwill	12,654		12,654
	Other long-term assets	9		15
	Accounts payable & accrued expenses	364		230
	Deferred tax liabilities, net	2,890		2,890
	Noncontrolling interests	9,258		10,003
Reconciliation of equity (net assets) attributable to the noncontrolling interests	The following is a reconciliation of equity (net assets) attributable to the noncontrolling interests (in thousands):
		Nine Months Ended
		September 30,
		2013		2012
	Noncontrolling interests at beginning of period	$	10,003	$	10,705
	Less: Net loss attributable to the noncontrolling interests	745		672
	Noncontrolling interests at end of period	$	9,258	$	10,033

Balance_Sheet_Reserves_Tables

Balance Sheet Reserves (Tables)	9 Months Ended
	Sep. 30, 2013
Valuation and Qualifying Accounts [Abstract]
Balances Of Reserves For Accounts Receivable And Inventory Table	The balances of the reserves for accounts receivable and inventory are as follows (in thousands):
		September 30, 2013		December 31, 2012
	Reserves for accounts receivable and sales returns	$	3,362	$	2,780
	Reserves for excess and obsolete inventory	$	18,722	$	16,856

Marketable_Securities_and_Fair1

Marketable Securities and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Composition of marketable securities	Realized gains and losses from the sale of marketable securities, if any, are determin
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):
		Total			Quoted Price in			Significant Other		Significant
					Active Market			Observable Inputs		Unobservable
					(Level 1)			(Level 2)		Inputs (Level 3)
	September 30, 2013:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	59,107		$	59,107		$	—	$	—
	Certificates of deposit	1,674			1,674			—		—
	Corporate notes	85,121			—			85,121		—
	Commercial paper	14,992			—			14,992		—
	U.S. government treasury securities	63,552			63,552			—		—
	Securities of government-sponsored entities	123,457			—			123,457		—
	Total cash equivalents, marketable securities and restricted investments	$	347,903		$	124,333		$	223,570	$	—
	Contingent Consideration:
	Acquisition-related liabilities, current	$	(573	)	$	—		$	—	$	(573	)
	Acquisition-related liabilities, non-current	$	(576	)	$	—		$	—	$	(576	)
	Total contingent consideration	$	(1,149	)	$	—		$	—	$	(1,149	)
	December 31, 2012:
	Cash Equivalents, Marketable Securities and Restricted Investments:
	Money market funds	$	89,101		$	89,101		$	—	$	—
	Certificates of deposit	998			998			—		—
	Corporate notes	42,447			—			42,447		—
	Commercial paper	9,997			—			9,997		—
	U.S. government treasury securities	56,472			56,472			—		—
	Securities of government-sponsored entities	198,326			—			198,326		—
	Total cash equivalents, marketable securities and restricted investments	$	397,341		$	146,571		$	250,770	$	—
	Contingent Consideration:
	Acquisition-related liabilities, non-current	$	(1,074	)	$	—		$	—	$	(1,074	)
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation	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):
		Nine Months Ended September 30,
		2013			2012
	Fair value measurement at beginning of period	$	1,074		$	32,221
	Contingent consideration liability recorded upon acquisition	—			1,019
	Change in fair value measurement included in operating expenses	75			708
	Contingent consideration settled	—			(530		)
	Fair value measurement at end of period	$	1,149		$	33,418

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended										12 Months Ended
	Sep. 30, 2013										Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and intangible assets	Goodwill and intangible assets consisted of the following (in thousands, except years):
												Weighted-	Gross		Accumulated			Intangible
		Weighted-		Gross		Accumulated			Intangible			Average	Amount		Amortization			Assets, net
		Average		Amount		Amortization			Assets, net			Amortization
		Amortization										Period
		Period										(in years)
		(in years)									December 31, 2012:
	September 30, 2013:										Intangible Assets Subject to Amortization:
	Intangible Assets Subject to Amortization:										Purchased technology:
	Purchased technology:										Developed technology	10	$	55,178	$	(14,966	)	$	40,212
	Developed technology	10		$	56,328	$	(19,668	)	$	36,660
											Manufacturing know-how and trade secrets	12	21,712		(7,996		)	13,716
	Manufacturing know-how and trade secrets	12		21,979		(9,412		)	12,567
											Trade name and trademarks	11	9,500		(2,333		)	7,167
	Trade name and trademarks	11		9,500		(3,071		)	6,429
											Customer relationships	9	39,330		(9,703		)	29,627
	Customer relationships	8		43,865		(17,124		)	26,741
												10	$	125,720	$	(34,998	)	$	90,722
		10		$	131,672	$	(49,275	)	$	82,397
											Intangible Assets Not Subject to Amortization:
	Intangible Assets Not Subject to Amortization:										In-process research and development							10,640
	In-process research and development								10,640
											Goodwill							154,106
	Goodwill								154,913
											Total goodwill and intangible assets, net							$	255,468
	Total goodwill and intangible assets, net								$	247,950
Future amortization expense related to intangible assets	Total future amortization expense related to intangible assets subject to amortization at September 30, 2013 is set forth in the table below (in thousands):
	Remaining 2013	$	4,971
	2014	13,603
	2015	12,515
	2016	12,040
	2017	9,688
	2018	9,171
	Thereafter through 2026	20,409
	Total future amortization expense	$	82,397

Senior_Convertible_Notes_Table

Senior Convertible Notes (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Net carrying amount of the debt component	The carrying values of the Company’s Senior Convertible Notes are as follows (in thousands):
		September 30, 2013			December 31, 2012
	2.75% Senior Convertible Notes due 2017:
	Principal amount	$	402,500		$	402,500
	Unamortized debt discount	(59,948		)	(70,096		)
		342,552			332,404
	2.25% Senior Convertible Notes due 2013	—			74,311
	Total Senior Convertible Notes	$	342,552		$	406,715

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
	Numerator:
	Net income attributable to NuVasive, Inc.	$	7,511		$	2,354		$	1,893	$	5,890
	Denominator for basic and diluted net income per share:
	Weighted average common shares outstanding for basic	44,572			43,488			44,339		43,227
	Dilutive potential common stock outstanding:
	Stock options and Employee Stock Purchase Plan (ESPP)	473			317			304		215
	Restricted stock units	2,175			930			1,744		709
	Weighted average common shares outstanding for diluted	47,220			44,735			46,387		44,151
	Basic net income per share attributable to NuVasive, Inc.	$	0.17		$	0.05		$	0.04	$	0.14
	Diluted net income per share attributable to NuVasive, Inc.	$	0.16		$	0.05		$	0.04	$	0.13
Anti-dilutive common stock equivalents not included in calculation of net income per diluted share	The following weighted outstanding common stock equivalents were not included in the calculation of net income per diluted share because their effects were anti-dilutive (in thousands):
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Stock options, ESPP shares and unvested restricted stock units	4,957		5,921			5,759		6,047
	Warrants	11,998		14,694			13,768		14,694
	Senior Convertible Notes	9,553		11,214			10,003		11,214
	Total	26,508		31,829			29,530		31,955

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP	The weighted average assumptions used to estimate the fair value of stock purchase rights under the ESPP are as follows:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013			2012
	ESPP
	Volatility	57	%	55	%		57	%		55	%
	Expected term (years)	1.7		1.6			1.6			1.5
	Risk free interest rate	0.2	%	0.2	%		0.2	%		0.2	%
	Expected dividend yield	—	%	—	%		—	%		—	%
Compensation costs included in statement of income for all stock-based compensation arrangements	The compensation cost that has been included in the statement of operations for all stock-based compensation arrangements was as follows (in thousands):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013			2012				2013			2012
	Sales, marketing and administrative expense	$	7,965		$	4,844			$	22,667		$	18,723
	Research and development expense	448			567				1,239			1,624
	Cost of goods sold	41			23				96			53
	Total stock-based compensation expense	$	8,454		$	5,434			$	24,002		$	20,400

Business_Segment_Product_and_G1

Business Segment, Product, and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Revenue from External Customers by Products and Services	The Company’s Monitoring Service offering includes IOM services. Revenue by product line offerings was as follows (in thousands):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
	Spine Surgery Products	$	131,137	$	112,590	$	382,485	$	343,962
	Biologics	28,743		26,158		83,754		81,256
	Monitoring Service	9,276		9,643		28,119		29,283
	Total Revenue	$	169,156	$	148,391	$	494,358	$	454,501
Schedule of Revenue and Net Property and Equipment by Geographical Areas [Table Text Block]	Revenue and property and equipment, net, by geographic area were as follows (in thousands):
		Revenue								Property and Equipment, Net
		Three Months Ended				Nine Months Ended				As of September 30,		As of December 31,
		September 30,				September 30,
		2013		2012		2013		2012		2013		2012
	United States	$	152,377	$	136,885	$	450,024	$	422,754	$	112,976	$	112,701
	International (excludes Puerto Rico)	16,779		11,506		44,334		31,747		17,820		12,422
	Total	$	169,156	$	148,391	$	494,358	$	454,501	$	130,796	$	125,123

Investment_in_Progentix_Orthob2

Investment in Progentix Orthobiology, B.V. (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Components of total assets and liabilities of Progentix
Noncontrolling Interest in Variable Interest Entity	$9,258	$0
Noncontrolling interests	0	10,003	10,033	10,705
Progentix Orthobiology [Member]
Components of total assets and liabilities of Progentix
Total current assets	523	657
Identifiable intangible assets, net	14,520	14,871
Goodwill	12,654	12,654
Other long-term assets	9	15
Accounts payable & accrued expenses	364	230
Deferred tax liabilities, net	$2,890	$2,890

Reconciliation_of_Equity_Net_A

Reconciliation of Equity (Net Assets) Attributable to the Noncontrolling Interests (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Reconciliation of equity (net assets) attributable to the noncontrolling interests
Noncontrolling interests at beginning of period			$10,003	$10,705
Net loss attributable to noncontrolling interests	231	215	745	672
Noncontrolling interests at end of period	0	10,033	0	10,033
Noncontrolling Interests	$9,258		$9,258		$0

Business_Combinations_Details_

Business Combinations (Details Textual) (Progentix Orthobiology [Member], USD $)	Sep. 30, 2013	Dec. 31, 2009	Dec. 31, 2009	Dec. 31, 2009
In Millions, unless otherwise specified	Senior Secured Facility [Member]	Senior Secured Facility [Member]	Preferred Stock Purchase Agreement [Member]	Option Purchase Agreement [Member]
Business Combinations (Textual) [Abstract]
Percentage of ownership Interests acquired			40.00%
Cash payment on purchase of outstanding shares			$10
Maximum Amount of loan that can be borrowed by Progentix from NuVasive		5
Advanced loan accordance to loan agreement	5
Accrued interest rate of loan		6.00%
Call option remaining variable interest entity ownership percentage				60.00%
Amount of remaining shares				35
Business Acquisition Maximum Purchase price of shares				$35
Term of distribution agreement years				10 years
Percentage of minority interest represented by preferred stock			18.00%
Percentage of cumulative dividend			cumulative 8% dividend
Percentage of cumulative dividend, percent			8.00%

Balance_Sheet_Reserves_Details

Balance Sheet Reserves (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Valuation and Qualifying Accounts [Abstract]
Reserves for accounts receivable and sales returns	$3,362	$2,780
Reserves for excess and obsolete inventory	$18,722	$16,856

Marketable_Securities_and_Fair2

Marketable Securities and Fair Value Measurements - Composition of Marketable Securities (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Composition of marketable securities
Available-for-sale Securities, Cost	$288,711	$308,175
Available-for-sale Securities, Gross Unrealized Gains	130	87
Available-for-sale Securities, Gross Unrealized Losses	-45	-22
Available-for-sale Securities, Fair Value	288,796	308,240
Restricted Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	86,556	85,402
Available-for-sale Securities, Gross Unrealized Gains	31	23
Available-for-sale Securities, Gross Unrealized Losses	-4	-2
Available-for-sale Securities, Fair Value	86,583	85,423
Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	109,191	138,368
Available-for-sale Securities, Gross Unrealized Gains	41	38
Available-for-sale Securities, Gross Unrealized Losses	-18	-1
Available-for-sale Securities, Fair Value	109,214	138,405
Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	92,964	84,405
Available-for-sale Securities, Gross Unrealized Gains	58	26
Available-for-sale Securities, Gross Unrealized Losses	-23	-19
Available-for-sale Securities, Fair Value	92,999	84,412
Certificates of deposit [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	1,099	998
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	1,099	998
Certificates of deposit [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	575
Available-for-sale Securities, Gross Unrealized Gains	0
Available-for-sale Securities, Gross Unrealized Losses	0
Available-for-sale Securities, Fair Value	575
Corporate notes [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	58,787	19,169
Available-for-sale Securities, Gross Unrealized Gains	23	3
Available-for-sale Securities, Gross Unrealized Losses	-18	-1
Available-for-sale Securities, Fair Value	58,792	19,171
Corporate notes [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	26,332	23,293
Available-for-sale Securities, Gross Unrealized Gains	15	0
Available-for-sale Securities, Gross Unrealized Losses	-18	-17
Available-for-sale Securities, Fair Value	26,329	23,276
Commercial paper [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	14,992	9,995
Available-for-sale Securities, Gross Unrealized Gains	0	2
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	14,992	9,997
U.S. government treasury securities [Member] | Restricted Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	47,407	31,784
Available-for-sale Securities, Gross Unrealized Gains	22	5
Available-for-sale Securities, Gross Unrealized Losses	-2	-1
Available-for-sale Securities, Fair Value	47,427	31,788
U.S. government treasury securities [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	14,616	17,055
Available-for-sale Securities, Gross Unrealized Gains	8	6
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	14,624	17,061
U.S. government treasury securities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	1,500	7,619
Available-for-sale Securities, Gross Unrealized Gains	1	4
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	1,501	7,623
Securities of government-sponsored entities [Member] | Restricted Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	39,149	53,618
Available-for-sale Securities, Gross Unrealized Gains	9	18
Available-for-sale Securities, Gross Unrealized Losses	-2	-1
Available-for-sale Securities, Fair Value	39,156	53,635
Securities of government-sponsored entities [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	19,697	91,151
Available-for-sale Securities, Gross Unrealized Gains	10	27
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	19,707	91,178
Securities of government-sponsored entities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities, Cost	64,557	53,493
Available-for-sale Securities, Gross Unrealized Gains	42	22
Available-for-sale Securities, Gross Unrealized Losses	-5	-2
Available-for-sale Securities, Fair Value	$64,594	$53,513
Minimum [Member] | Certificates of deposit [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year
Minimum [Member] | Corporate notes [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year
Minimum [Member] | U.S. government treasury securities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year
Minimum [Member] | Securities of government-sponsored entities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity		1 year
Maximum [Member] | Certificates of deposit [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year	1 year
Maximum [Member] | Certificates of deposit [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	2 years
Maximum [Member] | Corporate notes [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year	1 year
Maximum [Member] | Corporate notes [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	2 years
Maximum [Member] | Commercial paper [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year	1 year
Maximum [Member] | U.S. government treasury securities [Member] | Restricted Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	2 years	2 years
Maximum [Member] | U.S. government treasury securities [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year	1 year
Maximum [Member] | U.S. government treasury securities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	2 years
Maximum [Member] | Securities of government-sponsored entities [Member] | Restricted Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	2 years	2 years
Maximum [Member] | Securities of government-sponsored entities [Member] | Short-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity	1 year	1 year
Maximum [Member] | Securities of government-sponsored entities [Member] | Long-term Investments [Member]
Composition of marketable securities
Available-for-sale Securities Contractual Maturity		2 years

Marketable_Securities_and_Fair3

Marketable Securities and Fair Value Measurements - Fair Value of Assets and Liabilities (Details) (Fair value measurements on recurring basis [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	$347,903	$397,341
Contingent Consideration Fair Value Disclosure, Current	-573
Acquisition-related liabilities, non-current	-576
Contingent Consideration:
Acquisition-related liabilities	-1,149	-1,074
Money Market Funds [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	59,107	89,101
Certificates of deposit [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	1,674	998
Corporate notes [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	85,121	42,447
Commercial paper [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	14,992	9,997
U.S. government treasury securities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	63,552	56,472
Securities of government-sponsored entities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	123,457	198,326
Quoted price in active market (Level 1) [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	124,333	146,571
Contingent Consideration Fair Value Disclosure, Current	0
Acquisition-related liabilities, non-current	0
Contingent Consideration:
Acquisition-related liabilities	0	0
Quoted price in active market (Level 1) [Member] | Money Market Funds [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	59,107	89,101
Quoted price in active market (Level 1) [Member] | Certificates of deposit [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	1,674	998
Quoted price in active market (Level 1) [Member] | Corporate notes [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Quoted price in active market (Level 1) [Member] | Commercial paper [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Quoted price in active market (Level 1) [Member] | U.S. government treasury securities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	63,552	56,472
Quoted price in active market (Level 1) [Member] | Securities of government-sponsored entities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant other observable inputs (Level 2) [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	223,570	250,770
Contingent Consideration Fair Value Disclosure, Current	0
Acquisition-related liabilities, non-current	0
Contingent Consideration:
Acquisition-related liabilities	0	0
Significant other observable inputs (Level 2) [Member] | Money Market Funds [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant other observable inputs (Level 2) [Member] | Certificates of deposit [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant other observable inputs (Level 2) [Member] | Corporate notes [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	85,121	42,447
Significant other observable inputs (Level 2) [Member] | Commercial paper [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	14,992	9,997
Significant other observable inputs (Level 2) [Member] | U.S. government treasury securities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant other observable inputs (Level 2) [Member] | Securities of government-sponsored entities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	123,457	198,326
Significant unobservable inputs (Level 3) [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Contingent Consideration Fair Value Disclosure, Current	-573
Acquisition-related liabilities, non-current	-576
Contingent Consideration:
Acquisition-related liabilities	-1,149	-1,074
Significant unobservable inputs (Level 3) [Member] | Money Market Funds [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant unobservable inputs (Level 3) [Member] | Certificates of deposit [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant unobservable inputs (Level 3) [Member] | Corporate notes [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant unobservable inputs (Level 3) [Member] | Commercial paper [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant unobservable inputs (Level 3) [Member] | U.S. government treasury securities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	0	0
Significant unobservable inputs (Level 3) [Member] | Securities of government-sponsored entities [Member]
Marketable Securities and Restricted Investments
Total marketable securities and restricted investments	$0	$0

Marketable_Securities_and_Fair4

Marketable Securities and Fair Value Measurements - Estimated Fair Value of Liabilities Measured on Recurring Basis using Significant Unobservable Inputs (Level 3) (Details 1) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Fair Value Disclosures [Abstract]
Business Acquisition, Contingent Consideration, at Fair Value	$0	$1,019
Changes in the estimated fair value for the Company's liabilities measured using significant unobservable inputs (Level 3)
Fair value measurement at beginning of period	1,074	32,221
Change in fair value measurement included in operating expenses and other income (expense)	75	708
Contingent consideration paid or settled	0	530
Fair value measurement at end of period	$1,149	$33,418

Marketable_Securities_and_Fair5

Marketable Securities and Fair Value Measurements (Details Textual)	9 Months Ended			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	31-May-09	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	USD ($)	Cervitech [Member]	Cervitech [Member]	Immaterial Acquisition [Member]	Immaterial Acquisition 2012 [Member]	Immaterial Acquisition 2012 [Member]
	Milestone	USD ($)	USD ($)	USD ($)	USD ($)	EUR (€)
	investment
Investments, Debt and Equity Securities [Abstract]
Impairment charges recorded for earnings	$0
Unrealized loss position investment	0
Business Acquisition [Line Items]
Maximum additional payment the Company is contingently obligated to make due to Cervitech acquisition			33,000,000			2,000,000
Acquisition-related liabilities		33,000,000			1,100,000
Number of milestone	2
Payment of contingent consideration				$500,000

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets (Details 1) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Intangible Assets Subject to Amortization:
Weighted Average Amortization Period	10 years	10 years
Gross Amount	$131,672	$125,720
Accumulated Amortization	-49,275	-34,998
Intangible Assets, net	82,397	90,722
Intangible Assets Not Subject to Amortization:
In-process research and development	10,640	10,640
Goodwill	154,913	154,106
Total intangible assets, net	247,950	255,468
Developed technology [Member]
Intangible Assets Subject to Amortization:
Weighted Average Amortization Period	10 years	10 years
Gross Amount	56,328	55,178
Accumulated Amortization	-19,668	-14,966
Intangible Assets, net	36,660	40,212
Manufacturing know-how and trade secrets [Member]
Intangible Assets Subject to Amortization:
Weighted Average Amortization Period	12 years	12 years
Gross Amount	21,979	21,712
Accumulated Amortization	-9,412	-7,996
Intangible Assets, net	12,567	13,716
Trade name and trademarks [Member]
Intangible Assets Subject to Amortization:
Weighted Average Amortization Period	11 years	11 years
Gross Amount	9,500	9,500
Accumulated Amortization	-3,071	-2,333
Intangible Assets, net	6,429	7,167
Customer relationships [Member]
Intangible Assets Subject to Amortization:
Weighted Average Amortization Period	8 years	9 years
Gross Amount	43,865	39,330
Accumulated Amortization	-17,124	-9,703
Intangible Assets, net	$26,741	$29,627

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets (Details 2) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining 2013	$4,971
Future amortization expense related to intangible assets
2013	13,603
2014	12,515
2015	12,040
2016	9,688
2017	9,171
Thereafter through 2026	20,409
Intangible Assets, net	$82,397	$90,722

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets (Details Textual) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense related to intangible assets	$4,974	$3,081	$14,263	$8,830

Senior_Convertible_Notes_Detai

Senior Convertible Notes (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Jun. 30, 2011
In Thousands, unless otherwise specified
Net carrying amount of the debt component
Senior Convertible Notes	$342,552	$406,715
2.75% Senior Convertible Notes due 2017 [Member]
Net carrying amount of the debt component
Principal amount	402,500	402,500	402,500
Unamortized debt discount	-59,948	-70,096
Senior Convertible Notes	342,552	332,404
2.25% Senior Convertible Notes Due 2013 [Member]
Net carrying amount of the debt component
Senior Convertible Notes	$0	$74,311

Senior_Convertible_Notes_Detai1

Senior Convertible Notes (Details Textual) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

6 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Jun. 30, 2011

Sep. 30, 2013

Jun. 30, 2011

Sep. 30, 2013

Dec. 31, 2011

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2011

Dec. 31, 2008

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2008

2.75% Senior Convertible Notes due 2017 [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.25% Senior Convertible Notes Due 2013 [Member]

2.25% Senior Convertible Notes Due 2013 [Member]

2.25% Senior Convertible Notes Due 2013 [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.75% Senior Convertible Notes due 2017 [Member]

2.25% Senior Convertible Notes Due 2013 [Member]

Senior Convertible Notes (Textual) [Abstract]

Interest rate on convertible notes

2.75%

2.25%

Principal amount of senior convertible notes

$402,500,000

$402,500,000

$402,500,000

$402,500,000

$230,000,000

Additional purchase of unsecured senior convertible notes

52,500,000

Net proceeds of unsecured senior convertible notes

359,200,000

208,400,000

Debt instrument, maturity date

1-Jul-17

15-Mar-13

Number of common shares authorized

120,000,000

120,000,000

70,000,000

Initial conversion rate adjustment Shares

23.7344

Base principal amount per note

1,000

Initial conversion price of convertible notes

$42.13

Fair value of outstanding notes

392,800,000

392,800,000

361,300,000

Consecutive trading days immediately preceding calendar quarter

20 days

30 days

Percentage of conversion price

130.00%

98.00%

Business day period

5 days

Fair value of debt conversion cost

88,900,000

Debt discount, interest rate

8.00%

Debt Instrument, convertible carrying amount

49,300,000

49,300,000

49,300,000

Contractual Coupon Interest Expense

2,800,000

8,300,000

2,800,000

8,300,000

Amortization of Debt Discount (Premium)

3,200,000

10,148,000

9,435,000

3,400,000

10,100,000

Document Period End Date

30-Sep-13

Number of common stock to be purchased

9,553,096

Initial stock price at which shares to be purchased

$42.13

Cost of hedge transaction

80,100,000

Number of warrants to be acquired

477,654

400,000

5,100,000

Initial strike price at which Warrants to be acquired

988.51

49.13

Number of common stock shares preferred stock convertible into

20

Cash proceeds from the sale of warrants

47,900,000

Repurchase of Senior Convertible Notes

155,700,000

Repayments of Long-term Debt

$74,311,000

$0

$74,300,000

Class of Warrants or Rights, Expiration Date

8-Oct-13

Net_Income_Per_Share_Computati

Net Income Per Share Computation of Basic and Diluted Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net income attributable to NuVasive, Inc.	$7,511	$2,354	$1,893	$5,890
Denominator for basic and diluted net income per share:
Weighted average common shares outstanding for basic (in shares)	44,572	43,488	44,339	43,227
Dilutive potential common stock outstanding:
Weighted average common shares outstanding for diluted (in shares)	47,220	44,735	46,387	44,151
Earnings Per Share, Basic	$0.17	$0.05	$0.04	$0.14
Earnings Per Share, Diluted	$0.16	$0.05	$0.04	$0.13
Stock Options and ESPP [Member]
Dilutive potential common stock outstanding:
Stock options and ESPP (in shares)	473	317	304	215
Restricted Stock Units (RSUs) [Member]
Dilutive potential common stock outstanding:
Stock options and ESPP (in shares)	2,175	930	1,744	709

Net_Income_Per_Share_Antidilut

Net Income Per Share Anti-dilutive Common Stock Equivalents Not Included in Calculation of Net Income Per Diluted Share (Details)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Computation of basic and diluted earnings per share
Anti-dilutive securities excluded from computation of earnings per share	26,508	31,829	29,530	31,955
Stock Options and RSUs [Member]
Computation of basic and diluted earnings per share
Anti-dilutive securities excluded from computation of earnings per share	4,957	5,921	5,759	6,047
Warrants [Member]
Computation of basic and diluted earnings per share
Anti-dilutive securities excluded from computation of earnings per share	11,998	14,694	13,768	14,694
Senior Convertible Notes [Member]
Computation of basic and diluted earnings per share
Anti-dilutive securities excluded from computation of earnings per share	9,553	11,214	10,003	11,214

StockBased_Compensation_Detail

Stock-Based Compensation (Details 1) (ESPP [Member])	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
ESPP [Member]
Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP
Volatility	57.00%	55.00%	57.00%	55.00%
Expected term (years)	1 year 8 months	1 year 7 months	1 year 7 months	1 year 6 months
Risk free interest rate	0.20%	0.20%	0.20%	0.20%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

StockBased_Compensation_Detail1

Stock-Based Compensation (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Compensation cost included in statement of income for all stock-based compensation arrangements
Stock based compensation expense	$8,454	$5,434	$24,002	$20,400
Sales, marketing and administrative expense [Member]
Compensation cost included in statement of income for all stock-based compensation arrangements
Stock based compensation expense	7,965	4,844	22,667	18,723
Research and development expense [Member]
Compensation cost included in statement of income for all stock-based compensation arrangements
Stock based compensation expense	448	567	1,239	1,624
Cost of goods sold [Member]
Compensation cost included in statement of income for all stock-based compensation arrangements
Stock based compensation expense	$41	$23	$96	$53

StockBased_Compensation_Detail2

Stock-Based Compensation (Details Textuals 1)

3 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Mar. 01, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Restricted Stock Units (RSUs) [Member]

Restricted Stock Units (RSUs) [Member]

Restricted Stock Units (RSUs) [Member]

Performance-Based Restricted Stock Units [Member]

Performance-Based Restricted Stock Units [Member]

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

Vesting in One Year [Member]

Vesting in One Year [Member]

Vesting in Two Years [Member]

Vesting in Two Years [Member]

Performance-Based Restricted Stock Units [Member]

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

Performance-Based Restricted Stock Units [Member]

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

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

Number of common stock issued to exercise stock options

24,000

29,000

48,000

Number of shares of common stock issued upon vesting of RSUs

70,000

510,000

339,000

117,000

Current Fiscal Year End Date

-19

Vesting percentage

33.33%

33.33%

50.00%

33.33%

50.00%

Expected volatility rate

49.00%

Risk free interest rate

0.13%

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Income tax expense	$860,000	$4,064,000	$20,000	$7,764,000
Effective income tax rate			1.71%
Tax benefit related to federal research and development credit			$900,000
Tax benefit related to federal research and development credit, percentage			77.00%

Business_Segment_Product_and_G2

Business Segment, Product, and Geographic Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
			segment
Segment Reporting [Abstract]
Number of Reportable Segments			1
Revenue from spine surgery product line offerings
Total revenues	$169,156	$148,391	$494,358	$454,501
Spine Surgery Products [Member]
Revenue from spine surgery product line offerings
Total revenues	131,137	112,590	382,485	343,962
Biologics [Member]
Revenue from spine surgery product line offerings
Total revenues	28,743	26,158	83,754	81,256
Monitoring Service [Member]
Revenue from spine surgery product line offerings
Total revenues	$9,276	$9,643	$28,119	$29,283

Business_Segment_Product_and_G3

Business Segment, Product, and Geographic Information Geographic Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	$169,156	$148,391	$494,358	$454,501
Property, Plant and Equipment, Net	130,796		130,796		125,123
UNITED STATES
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	152,377	136,885	450,024	422,754
Property, Plant and Equipment, Net	112,976		112,976		112,701
International [Member]
Revenues and Net Property and Equipment by Geographical Areas [Line Items]
Total revenues	16,779	11,506	44,334	31,747
Property, Plant and Equipment, Net	$17,820		$17,820		$12,422

Legal_Proceedings_Details

Legal Proceedings (Details) (USD $)	9 Months Ended		12 Months Ended		9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Dec. 31, 2011	Dec. 10, 2012
	Medtronic Litigation [Member]	Medtronic Litigation [Member]	Medtronic Litigation [Member]	Medtronic Litigation [Member]	Trademark Infringement [Member]	Trademark Infringement [Member]	Trademark Infringement [Member]
	patent
Legal Proceedings (Textual) [Abstract]
Number of patents assigned or licensed	12
Number of patents withdrawn	3
Number of patents remaining	9
Company's Patents in Initial Phase of Litigation	1
Number of Patents Selected for Litigation	3
Other Company's Patents in Initial Phase of Litigation	3
Litigation award		($101.20)		($101.20)
RoyaltyAccrualCharge			7.9
TransferOfFundsNotAvailableForWithdrawalOrUse	21
Company's cash and investment in escrow			113.3			62.5
Approximate loss contingency		13
Unrecorded royalty damages	0.7
Loss Contingency, Settlement Agreement, Consideration	7.5
Jury award					60
Release of funds from escrow							$62.50