Alphatec (ATEC) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Alphatec Holdings, Inc.
Entity Central Index Key	1,350,653
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Trading Symbol	ATEC
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q3
Amendment Flag	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		43,212,606

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash	$ 35,111	$ 22,466
Accounts receivable, net	12,204	14,822
Inventories, net	28,988	27,292
Prepaid expenses and other current assets	1,530	1,767
Current assets of discontinued operations	246	131
Total current assets	78,079	66,478
Property and equipment, net	12,295	12,670
Goodwill	14,469
Intangibles, net	26,345	5,248
Other assets	223	208
Noncurrent assets of discontinued operations	54	56
Total assets	131,465	84,660
Current liabilities:
Accounts payable	5,642	3,878
Accrued expenses	20,897	22,246
Current portion of long-term debt	6,186	3,306
Current liabilities of discontinued operations	419	312
Total current liabilities	33,144	29,742
Long-term debt, less current portion	34,285	37,767
Other long-term liabilities	16,220	20,206
Redeemable preferred stock, $0.0001 par value; 20,000 shares authorized at September 30, 2018 and December 31, 2017; 3,319 shares issued and outstanding at both September 30, 2018 and December 31, 2017	23,603	23,603
Commitments and contingencies
Stockholders' equity (deficit):
Common stock, $0.0001 par value; 200,000 shares authorized at September 30, 2018 and December 31, 2017; 43,153 and 19,857 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	4	2
Treasury stock, at cost, 2 shares, at both September 30, 2018 and December 31, 2017	(97)	(97)
Additional paid-in capital	506,078	436,803
Shareholder note receivable	(5,000)	(5,000)
Accumulated other comprehensive income	1,034	1,093
Accumulated deficit	(477,806)	(459,459)
Total stockholders’ equity (deficit)	24,213	(26,658)
Total liabilities and stockholders’ equity (deficit)	131,465	84,660
Series A Convertible Preferred Stock
Stockholders' equity (deficit):
Convertible preferred stock
Series B Convertible Preferred Stock
Stockholders' equity (deficit):
Convertible preferred stock

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Redeemable preferred stock, par value (dollars per share)	$ 0.0001	$ 0.0001
Redeemable preferred stock, shares authorized	20,000,000	20,000,000
Redeemable preferred stock, shares issued	3,319,000	3,319,000
Redeemable preferred stock, shares outstanding	3,319,000	3,319,000
Common stock, par value (dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	43,153,000	19,857,000
Common stock, shares outstanding	43,153,000	19,857,000
Treasury stock, shares	2,000	2,000
Series A Convertible Preferred Stock
Convertible preferred stock, par value (dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	15,000	15,000
Convertible preferred stock, shares issued	4,000
Convertible preferred stock, shares outstanding	4,000
Series B Convertible Preferred Stock
Convertible preferred stock, par value (dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	45,000	0
Convertible preferred stock, shares issued	0
Convertible preferred stock, shares outstanding	0

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 23,002	$ 23,099	$ 66,351	$ 75,456
Cost of revenues	8,088	8,587	23,597	28,417
Gross profit	14,914	14,512	42,754	47,039
Operating expenses:
Research and development	3,157	1,044	6,952	3,483
Sales and marketing	10,956	10,015	31,689	31,416
General and administrative	7,914	4,403	22,171	15,977
Amortization of intangible assets	187	172	551	516
Transaction-related expenses	66		1,546
Gain on settlement			(6,168)
Restructuring expenses	167	139	758	1,898
Gain on sale of assets				(856)
Total operating expenses	22,447	15,773	57,499	52,434
Operating loss	(7,533)	(1,261)	(14,745)	(5,395)
Interest and other expense, net	(1,754)	(1,822)	(5,183)	(5,677)
Loss from continuing operations before taxes	(9,287)	(3,083)	(19,928)	(11,072)
Income tax (benefit) provision	26	(7)	(1,697)	57
Loss from continuing operations	(9,313)	(3,076)	(18,231)	(11,129)
Loss from discontinued operations, net of applicable taxes	(42)	(61)	(116)	(220)
Net loss	$ (9,355)	$ (3,137)	$ (18,347)	$ (11,349)
Net loss per share, basic and diluted:
Continuing operations	$ (0.22)	$ (0.22)	$ (0.56)	$ (0.98)
Discontinued operations	0	(0.01)	0	(0.02)
Net loss per share, basic and diluted	$ (0.22)	$ (0.23)	$ (0.56)	$ (1)
Shares used in calculating basic and diluted net loss per share	42,497	13,938	32,658	11,349

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (9,355)	$ (3,137)	$ (18,347)	$ (11,349)
Foreign currency translation adjustments related to continuing operations	(47)	207	(59)	155
Comprehensive loss	$ (9,402)	$ (2,930)	$ (18,406)	$ (11,194)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (18,347)	$ (11,349)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,066	5,536
Stock-based compensation	3,442	1,669
Amortization of debt discount and debt issuance costs	1,571	2,107
Provision for doubtful accounts	131	(145)
Provision for excess and obsolete inventory	1,612	1,640
Deferred income tax expense	(1,227)	(1)
Gain on settlement	(6,168)
Gain on sale of assets		(856)
(Gain) loss on disposal of instruments	(275)	1,043
Accretion to contingent consideration	646
Changes in operating assets and liabilities:
Accounts receivable, net	2,527	5,354
Inventories, net	(3,117)	(1,294)
Prepaid expenses and other current assets	589	2,745
Other assets	(48)	297
Accounts payable	922	(3,597)
Accrued expenses and other	(316)	(11,552)
Other long-term liabilities	(3,267)
Deferred revenue	(261)	289
Net cash used in operating activities	(16,520)	(8,114)
Investing activities:
Purchases of property and equipment	(3,297)	(7,185)
Cash paid for acquisition of SafeOp Surgical, Inc.	(15,103)
Cash paid for acquisition of intangible assets	(150)
Cash received from sale of equipment	348	869
Net cash used in investing activities	(18,202)	(6,316)
Financing activities:
Borrowings under lines of credit	67,804	70,547
Repayments under lines of credit	(68,581)	(74,056)
Principal payments on capital lease obligations	(87)	(353)
Proceeds from sale of stock, net	51,554	17,210
Principal payments on term loan	(3,275)	(3,328)
Net cash provided by financing activities	47,415	10,020
Effect of exchange rate changes on cash	(48)	254
Net increase (decrease) in cash	12,645	(4,156)
Cash at beginning of period, including discontinued operations	22,466	19,593
Cash at end of period, including discontinued operations	35,111	15,437
Supplemental disclosure of cash flow information:
Cash paid for interest	3,387	3,568
Cash paid for income taxes	109	90
Purchases of property and equipment in accounts payable	$ 1,277	2,240
Common stock issued for acquisition of intangible assets		$ 473

The Company and Basis of Presen

The Company and Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Company and Basis of Presentation	1. The Company and Basis of Presentation The Company Alphatec Holdings, Inc. (the “Company”), through its wholly owned subsidiaries, Alphatec Spine, Inc. (“Alphatec Spine”) and SafeOp Surgical, Inc. (“SafeOp”), is a medical technology company that designs, develops, and markets technology for the treatment of spinal disorders associated with disease and degeneration, congenital deformities, and trauma. The Company's mission is to improve lives by providing innovative spine surgery solutions through the relentless pursuit of superior outcomes. The Company markets its products in the U.S. via independent sales agents and a direct sales force. The Company operates in one reportable business segment. On March 6, 2018, the Company and its newly-created wholly-owned subsidiary, Safari Merger Sub, Inc. (“Sub”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with SafeOp, a Delaware corporation, certain Key Stockholders of SafeOp and a Stockholder Representative. The Merger Agreement provides for a reverse triangular merger (the “Merger”), which was consummated on March 8, 2018, in which Sub was merged into SafeOp, with SafeOp being the surviving corporation and a wholly-owned subsidiary of the Company. See Note 8 for further information. On September 1, 2016, the Company completed the sale of its international distribution operations and agreements (collectively, the “International Business”) to Globus Medical Ireland, Ltd., a subsidiary of Globus Medical, Inc., and its affiliated entities (collectively “Globus”). As a result of this transaction, the International Business has been excluded from continuing operations for all periods presented in this Quarterly Report on Form 10-Q and is reported as discontinued operations. See Note 4 for additional information on the divestiture of the International Business. Recent Developments I n including the integration of next-generation neuromonitoring solutions, advancement of its product pipeline, and investment in sales and marketing to expand its market presence See Note 11 for further information. In November 2018, the Company entered into a Credit, Security and Guaranty Agreement (the “Credit Agreement”) with Squadron Medical Finance Solutions LLC (“Squadron”) for a $35.0 million secured term loan (the “Term Loan”). The majority of the proceeds of the Term Loan were used to retire the Company’s existing $29.2 million term debt with Globus Basis of Presentation The accompanying condensed consolidated balance sheet as of December 31, 2017, which has been derived from audited financial statements, and the unaudited interim condensed consolidated financial statements have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) related to a quarterly report on Form 10-Q. Certain information and note disclosures normally included in annual audited financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made in this Quarterly Report on Form 10-Q are adequate to make the information not misleading. The unaudited interim condensed consolidated financial statements reflect all adjustments, including normal recurring adjustments which, in the opinion of management, are necessary for a fair statement of the financial position and results of operations for the periods presented. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements for the year ended December 31, 2017, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 that was filed with the SEC on March 9, 2018. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018, or any other future periods. The accompanying condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern and do not include any adjustments that might result from the outcome of this uncertainty. A going concern basis of accounting contemplates the recovery of the Company’s assets and the satisfaction of its liabilities in the normal course of business. The Company’s annual operating plan projects that its existing working capital at September 30, 2018 of $44.9 million (including cash of $35.1 million) which includes the net proceeds of $51.6 million received as of September 30, 2018 from the equity offering that closed on March 8, 2018 (see Note 11), warrant and stock option exercises, as well as the amendments to its debt facilities (see Note 5), allows the Company to fund its operations through at least one year subsequent to the date the financial statements are issued. The Company has incurred significant net losses since inception and has relied on its ability to fund its operations through revenues from the sale of its products, equity financings and debt financings. As the Company has historically incurred losses, successful transition to profitability is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. This may not occur and, unless and until it does, the Company will continue to need to raise additional capital. Operating losses and negative cash flows may continue for at least the next year as the Company continues to incur costs related to the execution of its operating plan and introduction of new products. As more fully described in Note 5, the Company is a party to debt agreements with MidCap Funding IV, LLC (“MidCap”) (the “Debt Agreement”). The Debt Agreement includes traditional lending and reporting covenants, including a financial covenant that requires the Company to maintain a minimum fixed charge coverage ratio. On November 6, 2018, the Company entered into an Eighth Amendment to the MidCap Facility (the “MidCap Amendment”) to extend the date that the financial covenants of the MidCap Facility are effective from April 2019 to April 2020, and extended the minimum liquidity covenant through March 2020. Should at any time the Company fail to maintain compliance with this covenant, the Company will need to seek a waiver or amendment to the Debt Agreement. If the Company is unable to secure such a waiver or amendment, it may be required to classify its obligations under the Debt Agreement in current liabilities on its consolidated balance sheet. The Company may also be required to repay all or a portion of outstanding indebtedness under the Debt Agreement, which may require the Company to obtain further financing. There is no assurance that the Company will be able to obtain further financing, or do so on reasonable terms. Reclassification Certain amounts in the condensed consolidated statement of cash flows for the nine months ended September 30, 2017 have been reclassified to conform to the current period's presentation. None of the adjustments had any effect on the prior period cash flow totals.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2 to its audited consolidated financial statements for the year ended December 31, 2017, which are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 9, 2018. Except as discussed below, these accounting policies have not changed during the nine months ended September 30, 2018. Revenue Recognition The Company recognizes revenue from license and collaboration agreements in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers The adoption of this guidance did not have a material impact on the Company’s consolidated financial statements. The Company derives its revenues primarily from the sale of spinal surgery implants used in the treatment of spine disorders. The Company sells its products primarily through its direct sales force and independent distributors. Revenue is recognized when control of the promised goods are transferred to the customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods. Transfer of control generally occurs when the Company receives the written acknowledgment that the product has been used in a surgical procedure or upon shipment to third-party customers who immediately accept title to such product. The Company’s accounts three Warrants to Purchase Common Stock Warrants are accounted for in accordance with the applicable accounting guidance as either derivative liabilities or as equity instruments depending on the specific terms of the agreements. As of September 30, 2018, all warrants are classified within stockholders’ equity. The Company periodically evaluates changes in facts and circumstances that could impact the classification of warrants. Transaction-related Expenses The Company expensed certain costs related to the SafeOp acquisition, which primarily include third-party advisory and legal fees . Fair Value Measurements T he carrying amount of financial instruments consisting of cash, restricted cash, trade accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses, accrued compensation and current portion of long-term debt included in the Company’s consolidated financial statements are reasonable estimates of fair value due to their short maturities. Based on the borrowing rates currently available to the Company for loans with similar terms, management believes the fair value of long-term debt approximates its carrying value. Authoritative guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Level 2: Level 3: The Company does not maintain any financial assets that are considered to be Level 1, Level 2 or Level 3 instruments as of September 30, 2018. The fair value of the contingent consideration liability assumed in the SafeOp acquisition is recorded as part of the purchase price consideration of the acquisition. using a probability-weighted income approach, utilizing significant unobservable inputs including the probability of achieving each of the potential milestones and an estimated discount rate related to the risks of the expected cash flows attributable to the milestones. The following table provides a reconciliation of liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and nine months ended September 30, 2018 (in thousands): September 30, 2018 Balance at January 1, 2018 $ — Contingent consideration liability recorded upon acquisition of SafeOp 3,200 Change in fair value measurement — Balance at March 31, 2018 3,200 Change in fair value measurement 100 Balance at June 30, 2018 $ 3,300 Settlement of milestone #1 (1,446 ) Change in fair value measurement 546 Balance at September 30, 2018 $ 2,400 During the three months ended September 30, 2018, the Company achieved the first of the two milestones which was settled through the issuance of 443,421 shares of the Company’s common stock. See Note 8 for further information. The material factors that may impact the fair value of the contingent consideration, and therefore, this liability, are the probabilities of achieving the related milestones and the discount rate. Significant increases or decreases in any of the probabilities of success would result in a significantly higher or lower fair value, respectively. Any necessary Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , as modified by subsequently issued ASUs 2015-14, 2016-08, 2016-10, 2016-12 and 2016-20 (collectively “ASU 2014-09”). ASU 2014-09 superseded existing revenue recognition standards with a single model unless those contracts are within the scope of other standards. The revenue recognition principle in ASU 2014-09 is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company adopted the new standard effective January 1, 2018 using the modified retrospective approach applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASU 2014-09, while prior period amounts are not adjusted and continue to be reported in accordance with the historic accounting under ASC 605. The adoption of ASU 2014-09 did not have a material cumulative impact on the Company’s consolidated financial statements as of January 1, 2018. In August 2016, the FASB issued new accounting guidance, which eliminates the diversity in practice related to the classification of certain cash receipts and payments in the statement of cash flows, by adding or clarifying guidance on eight specific cash flow issues. The guidance is effective for annual and interim reporting periods in fiscal years beginning after December 15, 2017, with early adoption permitted. The amendments in this update should be applied retrospectively to all periods presented, unless deemed impracticable, in which case, prospective application is permitted. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business In May 2017, the FASB recently issued ASU 2017-09, Compensation-Stock Compensation , to provide clarity and reduce both 1) diversity in practice and 2) cost and complexity when applying the guidance in Topic 718 to a change in the terms or conditions of a share-based payment award. ASU 2017-09 provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting under Topic 718. The amendments in ASU 2017-09 are effective for fiscal and interim reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period. The amendments in ASU 2017-09 should be applied prospectively to an award modified on or after the adoption date. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Non-Controlling Interests with a Scope Exception. The ASU allows companies to exclude a down round feature when determining whether a financial instrument (or embedded conversion feature) is considered indexed to the entity’s own stock. As a result, financial instruments (or embedded conversion features) with down round features may no longer be required to be classified as liabilities. A company will recognize the value of a down round feature only when it is triggered and the strike price has been adjusted downward. For equity-classified freestanding financial instruments, such as warrants, an entity will treat the value of the effect of the down round, when triggered, as a dividend and a reduction of income available to common shareholders in computing basic earnings per share. For convertible instruments with embedded conversion features containing down round provisions, entities will recognize the value of the down round as a beneficial conversion discount to be amortized to earnings. The guidance in ASU 2017-11 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, and the guidance is to be applied using a full or modified retrospective approach. The Company early adopted the guidance in conjunction with the 2018 Private Placement. In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The Company early adopted the guidance during the second quarter of 2018. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 , Leases (Topic 842) In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other

Select Condensed Consolidated B

Select Condensed Consolidated Balance Sheet Details	9 Months Ended
	Sep. 30, 2018
Balance Sheet Related Disclosures [Abstract]
Select Condensed Consolidated Balance Sheet Details	3. Select Condensed Consolidated Balance Sheet Details Accounts Receivable, net Accounts receivable, net consist of the following (in thousands): September 30, 2018 December 31, 2017 Accounts receivable $ 12,391 $ 15,328 Allowance for doubtful accounts (187 ) (506 ) Accounts receivable, net $ 12,204 $ 14,822 Inventories, net Inventories, net consist of the following (in thousands): September 30, 2018 December 31, 2017 Raw materials $ 5,242 $ 4,969 Work-in-process 548 502 Finished goods 40,095 37,933 45,885 43,404 Less reserve for excess and obsolete finished goods (16,897 ) (16,112 ) Inventories, net $ 28,988 $ 27,292 Property and Equipment, net Property and equipment, net consist of the following (in thousands except as indicated): Useful lives (in years) September 30, 2018 December 31, 2017 Surgical instruments 4 $ 53,372 $ 53,198 Machinery and equipment 7 6,034 5,503 Computer equipment 3 3,813 3,500 Office furniture and equipment 5 2,911 2,794 Leasehold improvements various 1,765 1,714 Construction in progress n/a 92 336 67,987 67,045 Less accumulated depreciation and amortization (55,692 ) (54,375 ) Property and equipment, net $ 12,295 $ 12,670 Total depreciation expense was $1.5 million and $1.6 million for the three months ended September 30, 2018 and 2017 and $4.5 million and $4.8 million for the nine months ended September 30, 2018 and 2017, respectively. At both September 30, 2018 and December 31, 2017, assets recorded under capital leases of $2.1 million were included in the machinery and equipment balance. Amortization of assets under capital leases is included in depreciation expense. Intangible Assets, net In conjunction with the acquisition of SafeOp in March 2018, the Company recorded $21.6 million of new intangible assets. See Note 8 for further information regarding the acquisition. Intangible assets, net consist of the following (in thousands, except as indicated): Remaining Avg. Useful lives (in years) September 30, 2018 December 31, 2017 Developed technology 12 $ 26,975 $ 13,876 Intellectual property — 1,004 1,004 License agreements — 5,738 5,738 Trademarks and trade names — 792 732 Customer-related 2 7,458 7,458 Distribution network 4 4,027 4,027 In process research and development — 8,550 — 54,544 32,835 Less accumulated amortization (28,199 ) (27,587 ) Intangible assets, net $ 26,345 $ 5,248 Total amortization expense was $0.2 million and $0.2 million for the three months ended September 30, 2018 and 2017 and $0.6 million and $0.7 million for the nine months ended September 30, 2018 and 2017, respectively. Future amortization expense related to intangible assets as of September 30, 2018 is as follows (in thousands): Year Ending December 31, Remainder of 2018 $ 199 2019 1,437 2020 1,432 2021 1,432 2022 1,432 Thereafter 20,413 $ 26,345 Accrued Expenses Accrued expenses consist of the following (in thousands): September 30, 2018 December 31, 2017 Commissions and sales milestones $ 3,121 $ 3,360 Payroll and payroll related 3,692 2,968 Litigation settlement obligation 4,400 4,400 Professional fees 1,901 1,484 Royalties 1,142 1,269 Restructuring and severance accruals 336 520 Taxes 228 246 Guaranteed collaboration compensation, current — 4,485 Interest 576 376 Acquisition related - contingent consideration 2,400 — Other 3,101 3,138 Total accrued expenses $ 20,897 $ 22,246

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2018
Discontinued Operations And Disposal Groups [Abstract]
Discontinued Operations	4. Discontinued Operations In connection with the sale of the International Business, the Company entered into a product manufacture and supply agreement (the “Supply Agreement”) with Globus, pursuant to which the Company supplies to Globus certain of its implants and instruments (the “Products”), previously offered for sale by the Company in international markets at agreed-upon prices for a minimum term of three years, with the option for Globus to extend the term for up to two additional twelve month periods subject to Globus meeting specified purchase requirements. In accordance with authoritative guidance, sales to Globus are reported under continuing operations as the Company has continuing involvement under the Supply Agreement. During the three months ended September 30, 2018, the Company recorded $2.0 million in revenue and $1.8 million in cost of revenue from the Supply Agreement in continuing operations and during the nine months ended September 30, 2018, the Company recorded $5.7 million in revenue and $5.3 million in cost of revenue from the Supply Agreement in continuing operations. Included in the results of continuing operations for the three months ended September 30, 2017 are revenues of $2.3 million and cost of revenue of $2.0 million and for the nine months ended September 30, 2017 revenues of $9.2 million and cost of revenue of $7.9 million from the Supply Agreement. General and administrative expenses pertaining to discontinued operations on the Company’s condensed consolidated statements of operations were immaterial for the three and nine months ended September 30, 2018 and 2017. In addition, on September 1, 2016, the Company entered into a five-year term credit, security and guaranty agreement with Globus (the “Globus Facility Agreement”), as further described in Note 5, pursuant to which Globus agreed to loan the Company up to $30 million, subject to the terms and conditions set forth in the Globus Facility Agreement, as amended. In November 2018, the Globus facility was paid in full. See Note 16 for further information.

Debt

Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	5. Debt MidCap Facility Agreement The Company’s Amended Credit Facility with MidCap provides for a revolving credit commitment up to $22.5 million and provided for a term loan commitment up to $5 million. As of September 30, 2018, $9.5 million was outstanding under the revolving line of credit and the term loan was paid in full. The revolving line of credit interest accrues at London Interbank Offered Rate (“ As collateral for the Amended Credit Facility, MidCap has a first lien security interest in and a second lien on substantially all other assets. At September 30, 2018, $1.1 million remains as unamortized debt discount related to the Amended Credit Facility on the condensed consolidated balance sheet, which will be amortized over the remaining term of the Amended Credit Facility. The Amended Credit Facility also includes several event of default provisions, such as payment default, insolvency conditions and a material adverse effect clause, which could cause interest to be charged at a rate which is up to five percentage points above the rate effective immediately before the event of default or result in MidCap’s right to declare all outstanding obligations immediately due and payable. On March 8, 2018, the Company entered into a Seventh Amendment to the Amended Credit Facility to extend the date that the financial covenants of the Amended Credit Facility are effective from April 2018 to April 2019, and established a minimum liquidity covenant of $5.0 million through March 2019. The Company was in compliance with the covenants under the Amended Credit Facility at September 30, 2018. On November 6, 2018, the Company entered into the Eighth Amendment to the MidCap Facility to extend the date that the financial covenants of the MidCap Facility are effective from April 2019 to April 2020, and extended the minimum liquidity covenant through March 2020. Globus Facility Agreement On September 1, 2016, the Company and Globus entered into the Globus Facility Agreement, pursuant to which Globus loaned the Company $30 million, subject to the terms and conditions set forth in the Globus Facility Agreement. As of September 30, 2018, the outstanding balance under the Globus Facility Agreement was $29.2 million, which became due and payable in quarterly payments of $0.8 million which began in September 2018, with a final payment of the remaining outstanding principal and interest due on September 1, 2021. The term loan interest rate is priced at LIBOR plus 8.0% through September 1, 2018, and LIBOR plus 13.0%, thereafter. At September 30, 2018, the unamortized debt discount related to the Globus Facility Agreement on the condensed consolidated balance sheet was $0.6 million, which will be amortized over the remaining term of the Globus Facility Agreement See Note 16 for further information. Principal payments on the Company's debt were as follows as of September 30, 2018 (in thousands): Year Ending December 31, Remainder of 2018 $ 3,922 2019 3,605 2020 3,380 2021 21,667 2022 and thereafter 9,518 Total 42,092 Add: capital lease principal payments 135 Less: unamortized debt discount and debt issuance costs (1,756 ) Total 40,471 Less: current portion of long-term debt (6,186 ) Long-term debt, net of current portion $ 34,285 Credit Agreement with Squadron In November 2018, the Company entered into the Credit Agreement with Squadron for a $35.0 million secured Term Loan. The Term Loan matures over five years and bears interest at the one month LIBOR + 8% per annum. See Note 16 for further information.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Leases The Company leases certain equipment under capital leases which expire on various dates through 2022. The leases bear interest at rates ranging from 6.40% to 7.64% per annum, are generally due in monthly principal and interest installments and are collateralized by the related equipment. The Company also leases its buildings and certain equipment under operating leases which expire on various dates through 2021. Future minimum annual lease payments under such leases are as follows as of September 30, 2018 (in thousands): Year Ending December 31, Operating Capital Remainder of 2018 $ 411 $ 9 2019 1,665 37 2020 1,688 37 2021 1,009 37 2022 and thereafter — 37 $ 4,773 157 Less: amount representing interest (22 ) Present value of minimum lease payments 135 Current portion of capital leases (7 ) Capital leases, less current portion $ 128 Rent expense under operating leases for the three months ended September 30, 2018 and 2017 was $0.3 million and $0.3 million, respectively, . Litigation The Company is and may become involved in various legal proceedings arising from its business activities. While management is not aware of any litigation matter that in and of itself would have a material adverse impact on the Company’s consolidated results of operations, cash flows or financial position, litigation is inherently unpredictable, and depending on the nature and timing of a proceeding, an unfavorable resolution could materially affect the Company’s future consolidated results of operations, cash flows or financial position in a particular period. The Company assesses contingencies to determine the degree of probability and range of possible loss for potential accrual or disclosure in the Company’s consolidated financial statements. An estimated loss contingency is accrued in the Company’s consolidated financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Because litigation is inherently unpredictable and unfavorable resolutions could occur, assessing contingencies is highly subjective and requires judgments about future events. When evaluating contingencies, the Company may be unable to provide a meaningful estimate due to a number of factors, including the procedural status of the matter in question, the presence of complex or novel legal theories, and/or the ongoing discovery and development of information important to the matters. In addition, damage amounts claimed in litigation against the Company may be unsupported, exaggerated or unrelated to reasonably possible outcomes, and as such are not meaningful indicators of the Company’s potential liability. On February 13, 2018, NuVasive, Inc. filed suit against the Company in the United States District Court for the Southern District of California, alleging that certain of the Company’s products (including components of the Squadron™ Lateral Retractor, the Battalion™ Lateral Spacer and other components of the Battalion™ Lateral System), infringe, or contribute to the infringement of, U.S. Patent Nos. 7,819,801, 8,355,780, 8,439,832, 8,753,270, 9,833,227 (entitled “Surgical access system and related methods”), U.S. Patent No. 8,361,156 (entitled “Systems and methods for spinal fusion”), and U.S. Design Patent Nos. D652,519 (“Dilator”) and D750,252 (“Intervertebral Implant”). NuVasive is seeking unspecified monetary damages and a court injunction against future infringement by the Company. On March 8, 2018, the Company moved to dismiss NuVasive’s claims of infringement of its design patents on the grounds that those allegations fail to state a cognizable legal claim. On May 14, 2018, the Court ruled that NuVasive had failed to state a plausible claim for infringement of the asserted design patents and granted the Company’s motion to dismiss those claims with prejudice, as any further amendment would be futile. The Company filed its answer, affirmative defenses and counterclaims to NuVasive’s remaining claims on May 21, 2018. On March 26, 2018, NuVasive moved for a preliminary injunction, which, on March 27, 2018, the Court denied without prejudice for failure to comply with the Court’s chambers rules. On April 5, 2018, NuVasive again moved for a preliminary injunction. The Court held a hearing on the matter, having been fully briefed, on June 21, 2018. On July 10, 2018, the Court ruled that NuVasive had failed to establish either likelihood of success on the merits of its remaining claims or that it would suffer irreparable harm in the absence of a preliminary injunction. Accordingly, the Court denied NuVasive’s motion for preliminary injunction. On September 13, 2018, NuVasive filed an Amended Complaint for Patent Infringement, asserting additional infringement claims of U.S. Patent Nos. 9,924,859, 9,974,531 and 8,187,334. The Company filed its answer, affirmative defenses and counterclaims to NuVasive’s remaining claims on October 12, 2018. Trial has been set for October 2019. The parties currently are conducting discovery. The Company believes that the allegations lack merit and intends to vigorously defend all claims asserted. in accordance with authoritative accounting guidance, Indemnifications In the normal course of business, the Company enters into agreements under which it occasionally indemnifies third-parties for intellectual property infringement claims or claims arising from breaches of representations or warranties. In addition, from time to time, the Company provides indemnity protection to third-parties for claims relating to past performance arising from undisclosed liabilities, product liabilities, environmental obligations, representations and warranties, and other claims. In these agreements, the scope and amount of remedy, or the period in which claims can be made, may be limited. It is not possible to determine the maximum potential amount of future payments, if any, due under these indemnities due to the conditional nature of the obligations and the unique facts and circumstances involved in each agreement. In October 2017, NuVasive filed a lawsuit in Delaware Chancery Court against Mr. Miles, the Company’s Chairman and CEO, who was a former officer and board member of NuVasive. The Company itself was not initially a named defendant in this lawsuit; however, on June 28, 2018, NuVasive amended its complaint to add the Company as a defendant. As of September 30, 2018, the Company has not recorded any liability on the consolidated balance sheet related to this matter. On October 12, 2018, the Delaware Court ordered that NuVasive begin advancing legal fees for Mr. Miles’ defense in the lawsuit, as well as Mr. Miles’ legal fees incurred in pursuing advancement of his fees, pursuant to an indemnification agreement between NuVasive and Mr. Miles. Royalties The Company has entered into various intellectual property agreements requiring the payment of royalties based on the sale of products that utilize such intellectual property. These royalties primarily relate to products sold by Alphatec Spine and are based on fixed fees or calculated either as a percentage of net sales or on a per-unit sold basis. Royalties are included on the accompanying consolidated statements of operations as a component of cost of revenues. As of September 30, 2018, the Company is obligated to pay guaranteed minimum royalty payments under these agreements of approximately $7.8 million through 2022 and beyond.

Orthotec Settlement

Orthotec Settlement	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Orthotec Settlement	7. Orthotec Settlement On September 26, 2014, the Company entered into a Settlement and Release Agreement, dated as of August 13, 2014, by and among the Company and its direct subsidiaries, including Alphatec Spine, Inc., Alphatec Holdings International C.V., Scient'x S.A.S. and Surgiview S.A.S.; HealthpointCapital, LLC, HealthpointCapital Partners, L.P., HealthpointCapital Partners II, L.P., John H. Foster and Mortimer Berkowitz III; and Orthotec, LLC and Patrick Bertranou, (the “Settlement Agreement”). Pursuant to the Settlement Agreement, the Company agreed to pay Orthotec, LLC $49.0 million in cash, including initial cash payments totaling $1.75 million, which the Company previously paid in March 2014, and an additional lump sum payment of $15.75 million, which the Company previously paid in April 2014. The Company agreed to pay the remaining $31.5 million in 28 quarterly installments of $1.1 million and one additional quarterly installment of $0.7 million, commencing October 1, 2014. The payments set forth above are guaranteed by Stipulated Judgments held against the Company, HealthpointCapital Partners, L.P., HealthpointCapital Partners II, L.P., HealthpointCapital, LLC, John H. Foster and Mortimer Berkowitz III and, in the event of a default, will be entered and enforced against these entities and/or individuals in that order. In September 2014, the Company and HealthpointCapital entered into an agreement for joint payment of settlement whereby HealthpointCapital has agreed to contribute $5 million to the $49 million settlement amount. The $5 million is classified within stockholders’ equity on the Company’s condensed consolidated balance sheet due to the related party nature with HealthpointCapital and its affiliates. See Note 14 for further information. As of September 30, 2018, the Company has made installment payments in the aggregate of $35.1 million, with a remaining outstanding balance of $22.7 million (including interest). The Company has the right to prepay the amounts due without penalty. In addition, the unpaid balance of the amounts due accrues interest at the rate of 7% per year beginning May 15, 2014 until the amounts due are paid in full. The accrued but unpaid interest will be paid in quarterly installments of $1.1 million (or the full amount of the accrued but unpaid interest if less than $1.1 million) following the full payment of the $31.5 million in quarterly installments described above. No interest will accrue on the accrued interest. The Settlement Agreement provides for mutual releases of all claims in the Orthotec, LLC v. Surgiview, S.A.S, et al. matter in the Superior Court of California, Los Angeles County and all other related litigation matters involving the Company and its directors and affiliates.

Acquisition of SafeOp Surgical,

Acquisition of SafeOp Surgical, Inc.	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisition of SafeOp Surgical, Inc.	8. Acquisition of SafeOp Surgical, Inc. On March 9, 2018, the Company announced its acquisition of SafeOp, a privately-held provider of neuromonitoring technology designed to enable effective intra-operative nerve health assessment. At the time of acquisition SafeOp had FDA 510(k) approval for a somatosensory evoked potential (“SSEP”) monitoring technology. The Company is developing a product that will allow for both free run and triggered specific recording of muscle activity, also known as Electromyography (“EMG”). The Company expects to receive FDA approval for SafeOp’s EMG technology in early 2019 to complement the SSEP solution, and anticipates commercialization of the combined technology solution in early 2019. In addition to expanding the Company’s market presence in lateral spine surgery, the Company believes that the SafeOp solution will allow it to integrate neuromonitoring into its broader product portfolio and accelerate the transition to procedural integration of the entire portfolio. The Merger was accounted for using the acquisition method of accounting. The following unaudited pro forma results of operations assume that the Company acquired Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue $ 23,002 $ 23,153 $ 66,379 $ 75,613 Loss from continuing operations (9,485 ) (4,082 ) (18,952 ) (14,311 ) Net loss $ (9,527 ) $ (4,143 ) $ (19,068 ) $ (14,531 ) Net loss per share, basic and diluted $ (0.22 ) $ (0.21 ) $ (0.46 ) $ (0.93 ) The unaudited pro forma information presented above is not necessarily indicative of either the results of operations that would have occurred had the acquisition of SafeOp been effective on January 1, 2018 or 2017, respectively, or of the Company’s future results of operations. The results of operations for SafeOp have been included in the Company’s financial results since the acquisition date. For the three and nine months ended September 30, 2018, the Company’s total net revenues were not materially impacted from the Merger and net loss increased by $1.6 million and $3.0 million, respectively, due to SafeOp’s operating expenses. Under the term of the definitive merger agreement, the Company agreed to pay $15.1 million in cash and agreed to issue 3,265,132 shares of common stock. The Company paid the full $15.1 million in cash consideration during the nine months ended September 30, 2018. On March 8, 2018, the Company issued 2,975,209 shares of common stock valued at $9.8 million, based on the closing share price of $3.30, and issued an additional 115,621 shares of common stock during the second quarter of 2018 and the remaining 174,302 during the third quarter of 2018. The Company also issued $3 million in convertible notes that are convertible into a total of 987,578 shares, which includes total expected interest to be incurred, of common stock and issued warrants to purchase 2.2 million shares of common stock at an exercise price of $3.50 per share. Additional shares of common stock are issuable upon achievement of post-closing milestones as described further below. The total purchase price is presented below (in thousands): Cash paid and payable $ 15,103 Common stock issued and issuable 10,756 Note 3,000 Warrants 1,650 Contingent Consideration 3,200 Total $ 33,709 The Company has measured the identifiable assets and liabilities assumed at their acquisition date fair values separately from goodwill. The intangible assets acquired includes the EPAD tradename, in-process research and development (“IPR&D”) for the EMG technology, and the developed technology for SSEP. The fair value of the EPAD tradename was determined to be $60,000 with an estimated useful life of one year. The IPR&D for the EMG technology is considered to have an indefinite life until the development is completed (i.e. once FDA clearance is obtained), at which point the Company will determine the intangible asset’s estimate useful life. The developed SSEP technology has an estimated fair value of $13.1 million with an estimated useful life of 20 years. The Company has not presented any measurement period adjustments to the purchase price or the allocation detailed below for the three months ended September 30, 2018 due to their immaterial nature. Due to the short time frame since the acquisition date, the Company recorded the net tangible and intangible assets acquired and liabilities assumed based upon the preliminary valuation. The preliminary valuations, along with the Company’s estimates and assumptions, are subject to change within the measurement period (not to exceed one year). The primary areas of the preliminary purchase price allocation still in process relate to the fair values of assets acquired and liabilities assumed including: IPR&D, EPAD tradename and developed SSEP technology and related deferred tax consequences. The allocation of the purchase price to the assets acquired and liabilities assumed based on their fair values, is as follows (in thousands): Assets acquired: Accounts receivable $ 40 Inventory 192 Prepaid expenses and other current assets 89 Total current assets $ 321 Property and equipment, net 20 Other long-term assets 5 IPR&D 8,400 EPAD Tradename 60 Developed Technology 13,100 Total assets $ 21,906 Liabilities assumed: Accounts payable $ 54 Accrued expenses 148 Deferred tax liability 2,341 Total liabilities $ 2,543 Goodwill 14,346 Total consideration transferred $ 33,709 The purchase price exceeded the fair value of the net tangible and identifiable intangible assets acquired from SafeOp. As a result, the Company recorded goodwill in connection with the Merger. Specifically, the goodwill recorded as part of the Merger includes the assembled workforce and synergies associated with the combined entity. The goodwill is not expected to be deductible for tax purposes. As a result of the Merger, for the nine months ended September 30, 2018, the Company incurred $1.5 million in total transaction costs which, in accordance with authoritative accounting guidance, were expensed as incurred. The Company agreed to issue additional shares of common stock for up to $4.3 million upon achievement of post-closing milestones (the “Contingent Consideration”). The first milestone included payment of up to $1.4 million due 10 days after submission of an application for Regulatory Approval (as that term is defined in the Merger agreement) for an indication for regulatory clearance for use of a product that includes specifically recording of muscle activity (EMG). During the quarter ended September 30, 2018, the first milestone was achieved and the Company issued 443,421 shares of common stock as payment. The second milestone includes a potential payment of up to $2.9 million in common stock due 10 days after the receipt of Regulatory Approval from any Regulatory Authority (as those terms are defined in the Merger agreement) for an indication for use of a product that includes specifically EMG. The Contingent Consideration is recorded as a liability and measured at fair value using a probability-weighted income approach, utilizing significant unobservable inputs including the probability of achieving each of the potential milestones and an estimated discount rate related to the risks of the expected cash flows attributable to the milestones. The material factors that may impact the fair value of the Contingent Consideration, and therefore, this liability, are the probabilities of achieving the related milestones and the discount rate. Significant increases or decreases in any of the probabilities of success would result in a significantly higher or lower fair value, respectively. The fair value of the Contingent Consideration, and the associated liability relating to the Contingent Consideration at each reporting date, will be re-assessed with the changes in fair value reflected in earnings. For the three and nine months ended September 30, 2018, the fair value for the Contingent Consideration increased by $0.5 million and $0.6 million due to the proximity of the achievement of the milestones. The amount was recorded within research and development expense on the condensed consolidated statement of operations and a corresponding increase in the liability on the Company’s condensed consolidated balance sheet.

Sale of Assets

Sale of Assets	9 Months Ended
	Sep. 30, 2018
Discontinued Operations And Disposal Groups [Abstract]
Sale of Assets	9. Sale of Assets On May 5, 2017, the Company entered into an agreement to sell certain inventory and intellectual property to a third party for $1.0 million in consideration, payable via a credit to future minimum royalties owed to the third party under an existing exclusive license agreement between the two parties. The Company recorded a net gain on sale of assets of $0.9 million which is included under operating expenses on the Company’s condensed consolidated statement of operations.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	10. Net Loss Per Share Basic earnings per share (“EPS”) is calculated by dividing the net income or loss available to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted EPS is computed by dividing the net income available to common stockholders by the weighted average number of common shares outstanding for the period and the weighted average number of dilutive common stock equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, common stock subject to repurchase by the Company, convertible preferred stock, options, convertible notes and warrants are considered to be common stock equivalents and are only included in the calculation of diluted earnings per share when their effect is dilutive. The following table presents the computation of basic and diluted net loss per share for continuing and discontinued operations (in thousands, except per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Loss from continuing operations $ (9,313 ) $ (3,076 ) $ (18,231 ) $ (11,129 ) Loss from discontinued operations (42 ) (61 ) (116 ) (220 ) Net loss $ (9,355 ) $ (3,137 ) $ (18,347 ) $ (11,349 ) Denominator: Weighted average common shares outstanding 42,497 13,954 32,658 11,400 Weighted average unvested common shares subject to repurchase — (16 ) — (51 ) Weighted average common shares outstanding—basic and diluted 42,497 13,938 32,658 11,349 Net loss per share, basic and diluted: Continuing operations $ (0.22 ) $ (0.22 ) $ (0.56 ) $ (0.98 ) Discontinued operations $ (0.00 ) $ (0.01 ) $ (0.00 ) $ (0.02 ) Net loss per share, basic and diluted $ (0.22 ) $ (0.23 ) $ (0.56 ) $ (1.00 ) The anti-dilutive securities not included in diluted net Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Options to purchase common stock 325 2,948 367 1,861 Unvested restricted share awards — 16 — 51 Series A Convertible Preferred Stock 2,022 4,848 2,181 4,135 Convertible Notes 922 — 703 — Warrants to purchase common stock 1,075 — 1,956 1,013 Total 4,344 7,812 5,207 7,060

Stock Benefit Plans and Equity

Stock Benefit Plans and Equity Transactions	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Benefit Plans and Equity Transactions	11. Stock Benefit Plans and Equity Transactions Stock Benefit Plans On October 25, 2018, the Company’s Board of Directors adopted an amendment to the Company’s 2016 Equity Incentive Award Plan (the “Amendment”). The Amendment increases the maximum aggregate number of shares with respect to one or more stock rights that may be granted to any one person during any fiscal year from 500,000 to 1,250,000. Total stock-based compensation for the three and nine months ended September 30, 2018 and 2017 is as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Cost of revenues $ 18 $ 13 $ 51 $ 27 Research and development 179 (52 ) 192 239 Sales and marketing 223 134 527 358 General and administrative 1,255 355 2,672 1,045 Total $ 1,675 $ 450 $ 3,442 $ 1,669 The negative stock-based compensation expense recorded within the Company’s research and development expense in 2017 is a result of the revaluation of the Company’s Elite Medical Holdings and Pac 3 Surgical Collaboration liability. The agreement and subsequent termination are described further in Note 12. Shares Reserved for Future Issuance As of September 30, 2018, the Company had reserved shares of its common stock for future issuance as follows (in thousands): September 30, 2018 Stock options outstanding 4,880 Unvested restricted stock award 3,542 Employee stock purchase plan 232 Series A convertible preferred stock 2,022 Convertible Notes 988 Warrants outstanding 20,932 Distributor and surgeon royalty plans 4,000 Merger contingently issuable 887 Authorized for future grant under the Company equity plans 725 Total 38,208 Series A Convertible Preferred Stock In March 2017, the Company completed a private placement (the “2017 Private Placement”) with certain institutional and accredited investors, including certain directors, executive officers and employees of the Company (collectively, the “Purchasers”), providing for the sale by the Company of 1,809,628 shares of the Company’s common stock at a purchase price of $2.00 per share (the “Common Shares”) and 15,245 shares of newly designated Series A Convertible Preferred Stock at a purchase price of $1,000 per share (which shares were convertible into approximately 7,622,372 shares of common stock. The 2017 Private Placement generated aggregate gross proceeds to the Company of approximately $18.9 million. The Series A Convertible Preferred Stock are entitled to dividends on an as-if-converted basis in the same form as any dividends actually paid on shares of common stock or other securities. Except as otherwise required by law, the holders of Series A Convertible Preferred Stock have no right to vote on matters submitted to a vote of the Company’s stockholders. Without the prior written consent of 75% of the outstanding shares of Series A Convertible Preferred Stock, the Company may not: (a) alter or change adversely the powers, preferences or rights given to the Series A Convertible Preferred Stock or alter or amend the Certificate of Designation for the Series A Convertible Preferred Stock, (b) amend the Company’s certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders of Series A Convertible Preferred Stock, (c) increase the number of authorized shares of Series A Convertible Preferred Stock, or (d) enter into any agreement with respect to any of the foregoing. In the event of the dissolution and winding up of the Company, the proceeds available for distribution to the Company’s stockholders shall be distributed pari passu among the holders of the shares of common stock and Series A Convertible Preferred Stock, pro rata based upon the number of shares held by each such holder, as if the outstanding shares of Series A Convertible Preferred Stock were convertible, and were converted, into shares of common stock. During the nine months ended September 30, 2018, 1,274 shares of Series A Preferred Stock were converted into 636,997 shares of common stock. As of September 30, 2018, there were 4,043 shares of Series A Convertible Preferred Stock outstanding, which are convertible into 2,021,673 shares of Common Stock. 2017 Warrants In connection with the 2017 Private Placement, the Company issued warrants to purchase up to 9,432,000 shares of the Company’s common stock at an exercise price of $2.00 per share (the “2017 Common Stock Warrants”). The Company also issued warrants to purchase common stock to the exclusive placement agents for the issuance (“the 2017 Banker Warrants”). The 2017 Banker Warrants were for the purchase of up to an aggregate of 471,600 shares of the Company’s common stock with substantially the same terms as the 2017 Common Stock Warrants, except that they have an exercise price equal $2.50 per share. The 2017 Common Stock Warrants and the 2017 Banker Warrants (collectively, the “2017 Warrants”) expire on June 15, 2022. The 2017 Warrants, are exercisable for cash. The exercise price is subject to adjustment in the case of stock dividends or other distributions on shares of common stock or any other equity or equity equivalent securities payable in shares of common stock, stock splits, stock combinations, reclassifications or similar events affecting the Company’s common stock, and also, subject to limitations, upon any distribution of assets, including cash, stock or other property to the Company’s stockholders. Prior to exercise, holders of the 2017 Warrants do not have any of the rights of holders of the common stock purchasable upon exercise, including voting rights; however, the holders of the 2017 Warrants have certain rights to participate in distributions or dividends paid on the Company’s common stock to the extent set forth in the respective warrant agreements. The 2017 Warrants may not be exercised by the holder to the extent that the holder, together with its affiliates, would beneficially own, after such exercise more than 4.99% of the shares of the Company’s common stock then outstanding (subject to the right of the holder to increase or decrease such beneficial ownership limitation upon notice to us, provided that such limitation cannot exceed 9.99%) and provided that any increase in the beneficial ownership limitation shall not be effective until 61 days after such notice is delivered. If the Company effects a fundamental transaction, then upon any subsequent exercise of any 2017 Warrants, the holder thereof shall have the right to receive, for each share of common stock that would have been issuable upon such exercise immediately prior to the occurrence of such fundamental transaction, the number of shares of the successor’s or acquiring corporation’s common stock or of the Company’s common stock, if the Company is the surviving corporation, and any additional consideration receivable as a result of such fundamental transaction by a holder of the number of shares of common stock into which the 2017 Warrants were exercisable immediately prior to such fundamental transaction. In addition, in the event of a fundamental transaction (other than a fundamental transaction not approved by the Company’s Board of Directors), the Company or any successor entity shall, at the holder’s option, purchase the holder’s 2017 Warrants for an amount of cash equal to the value of the 2017 Warrants as determined in accordance with the Black Scholes option pricing model. A fundamental transaction as described in the 2017 Warrants generally includes any merger with or into another entity, sale of all or substantially all of the Company’s assets, tender offer or exchange offer, reclassification of the Company’s common stock or the consummation of a transaction whereby another entity acquires more than 50% of the Company’s outstanding voting stock. Based on the terms of the 2017 Warrants, the Company may be required to settle such warrants with cash upon a fundamental transaction, as defined. Since potential future cash settlement is deemed to be within the Company’s control, the 2017 Warrants are classified in stockholders’ equity in accordance with the authoritative accounting guidance. In conjunction with the 2018 Private Placement described further below, a holder of 2.4 million 2017 Warrants exercised 1.7 million 2017 During the three and nine Common Stock Warrants, respectively. As of September 30, 2018, there were 3,757,000 shares of 2017 Common Stock Warrants outstanding. During the nine months ended September 30, 2018, 304,182 of the 2017 Banker Warrants were exercised for total cash proceeds upon exercise of $0.8 million during the period. A total of 167,418 of the 2017 Banker Warrants remained outstanding as of September 30, 2018. Series B Convertible Preferred Stock On March 8, 2018, the Company completed the 2018 Private Placement to certain institutional and accredited investors, including certain directors and executive officers of the Company, at a purchase price of $1,000 per share, 45,200 of newly designated Series B Convertible Preferred Stock, which shares of preferred stock were converted into 12,617,857 shares of the Company’s common stock upon approval by the Company’s stockholders at the 2018 annual meeting of stockholders held in May 2018, and warrants to purchase up to 12,196,851 shares of common stock at an exercise price of $3.50 per share (the “2018 Common Stock Warrants”). The 2018 Common Stock Warrants became exercisable following stockholder approval at the annual meeting of stockholders, are subject to certain ownership limitations in certain cases, and expire five years after the date of such stockholder approval. The gross proceeds from the 2018 Private Placement were approximately $45.2 million. A total of 45,200 shares of Series B Convertible Preferred Stock are authorized for issuance under a Certificate of Designation of Preferences, Rights and Limitations of Series B Convertible Preferred Stock of the Company filed with the Secretary of State of the State of Delaware on March 8, 2018 in connection with the closing of the 2018 Private Placement. Each share of Series B Convertible Preferred Stock has a stated value of $1,000 and converted into approximately 317 shares of common stock. On May 17, 2018, the date 2018 Warrants The 2018 Common Stock Warrants (the “2018 Warrants”), are exercisable for cash or by cashless exercise. The exercise price of the 2018 Warrants is subject to adjustment in the case of stock dividends or other distributions on shares of common stock or any other equity or equity equivalent securities payable in shares of common stock, stock splits, stock combinations, reclassifications or similar events affecting the Company’s common stock, and also, subject to limitations, upon any distribution of assets, including cash, stock or other property to the Company’s stockholders. Prior to the exercise, holders of the 2018 Warrants do not have any of the rights of holders of the common stock purchasable upon exercise, including voting rights; however, the holders of the 2018 Warrants have certain rights to participate in distributions or dividends paid on the Company’s common stock to the extent set forth in the 2018 Common Stock Warrants. Some of the 2018 Warrants may not be exercised by the holder to the extent that the holder, together with its affiliates, would beneficially own, after such exercise more than 4.99% of the shares of the Company’s common stock then outstanding (subject to the right of the holder to increase or decrease such beneficial ownership limitation upon notice to us, provided that such limitation cannot exceed 9.99%) and provided that any increase in the beneficial ownership limitation shall not be effective until 61 days after such notice is delivered. If the Company effects a fundamental transaction, then upon any subsequent exercise of any 2018 Warrants, the holder thereof shall have the right to receive, for each share of common stock that would have been issuable upon such exercise immediately prior to the occurrence of such fundamental transaction, the number of shares of the successor’s or acquiring corporation’s common stock or of the Company’s common stock, if the Company is the surviving corporation, and any additional consideration receivable as a result of such fundamental transaction by a holder of the number of shares of common stock into which the 2018 Warrants were exercisable immediately prior to such fundamental transaction. A fundamental transaction as described in the 2018 Warrants generally includes any merger with or into another entity, sale of all or substantially all of the Company’s assets, tender offer or exchange offer, reclassification of the Company’s common stock or the consummation of a transaction whereby another entity acquires more than 50% of the Company’s outstanding voting stock. In addition to the 12,196,851 warrants issued in the 2018 Private Placement, the Company issued 1,275,000 warrants to an existing holder with identical terms to the 2018 Warrants, including the exercise price of $3.50. All the 2018 Warrants were deemed to qualify for equity classification under authoritative accounting guidance. A summary of all outstanding warrants is as follows: Number of Warrants Strike Price 2017 Common Stock Warrants 3,757,000 $ 2.00 2017 Banker Warrants 167,418 $ 2.50 2018 Common Stock Warrants 13,471,851 $ 3.50 Merger Warrants 2,200,000 $ 3.50 Executive 1,327,434 $ 5.00 Other 7,812 $ 19.20 Total 20,931,515 2017 Distributor Inducement Plan In December 2017, the Board approved and adopted the 2017 Distributor Inducement Plan which authorizes the Company to issue to distributors restricted shares of common stock of the Company and/or warrants to purchase the Company’s common stock. The warrants are issuable with an exercise price equal to the fair market value of the common stock on the date of issuance. Each warrant and common stock issuance is subject to a time-based or net sales-based vesting provision. As of September 30, 2018, 0.3 million warrants and 17,000 shares of common stock were earned under the 2017 Distributor Inducement Plan. Total expense for the plan was $0.1 million and $0.2 million for the three and nine months ended September 30, 2018, respectively. In December 2017, the Board of Directors also authorized grant of warrants to purchase 50,000 of the Company’s common stock, and 75,000 restricted stock units to a distributor. These warrants and restricted stock units are subject to time based and net sales based vesting conditions. 2017 Development Services Plan In December 2017, the Board approved and adopted the 2017 Development Services Plan which authorizes the Company to enter into Development Services Agreements with third-party individuals or entities whereby, upon the achievement of certain Company financial and commercial revenue milestones, future royalty payments for product and/or intellectual property development work may be paid in either cash or restricted shares of Company common stock at the option of the developer. Each common stock issuance would be subject to net sales-based vesting provisions and satisfaction of applicable laws and market regulations regarding the issuance of restricted shares to such developers. The Board of Directors authorized the grant of up to 3,000,000 shares of common stock under the Development Services Plan. No common stock elections, grants or cash payouts have been made as of September 30, 2018.

Termination and Settlement of E

Termination and Settlement of Elite Medical Holdings and Pac 3 Surgical Collaboration Agreement	9 Months Ended
	Sep. 30, 2018
Termination And Settlement Agreement [Abstract]
Termination and Settlement of Elite Medical Holdings and Pac 3 Surgical Collaboration Agreement	12. Termination and Settlement of Elite Medical Holdings and Pac 3 Surgical Collaboration Agreement In February 2018, the Company reached a settlement agreement with Elite Medical Holdings and Pac 3 Surgical, pursuant to which the Company made a cash payment of $0.4 million as the final and total compensation under the original agreement. In addition, the parties agreed to release each other and waive any and all rights and claims arising from the original agreement. The Company recorded a gain of approximately $6.2 million during the nine months ended September 30, 2018, reflecting the reversal of accrued obligations previously recorded under the collaboration.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes To calculate its interim tax provision, at the end of each interim period the Company estimates the annual effective tax rate and applies that to its ordinary quarterly earnings. In addition, the effect of changes in enacted tax laws or rates or tax status is recognized in the interim period in which the change occurs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in foreign jurisdictions, permanent and temporary differences between book and tax amounts, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, additional information is obtained or the tax environment changes. Intraperiod tax allocation rules require the Company to allocate the provision for income taxes between continuing operations and other categories of earnings, such as discontinued operations. In periods in which the Company has a year-to-date pre-tax loss from continuing operations and pre-tax income in other categories of earnings, such as discontinued operations, the Company must allocate the tax provision to the other categories of earnings, and then record a related tax benefit in continuing operations. The unrecognized tax benefits at September 30, 2018 and December 31, 2017 were $4.4 million for both periods, with no changes occurring during the nine month period. With the facts and circumstances currently available to the Company, it is reasonably possible that the amount of reserves that could reverse over the next 12 months is approximately $0.1 million. The Company recognizes interest and penalties related to uncertain tax positions as a component of the income tax provision. The Company is not currently under examination by the Internal Revenue Service, foreign, or state or local tax authorities. The income tax benefit from continuing operations for the three and nine months ended September 30, 2018 consists primarily of a release of the valuation allowance due to an increase in net deferred tax liabilities recorded as a result of the acquisition of SafeOp. The Company’s effective tax rate of 9.25% for the nine months ended September 30, 2018 differs from the federal statutory rate of 21% primarily due to the change in the valuation allowance related to the SafeOp acquisition, as noted above. The FASB issued ASU 2018-05, Income Taxes (Topic 740): "Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118" to address the application of GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act (the “Act”). At September 30, 2018, the Company has not completed its accounting for all of the tax effects of the Act and has not made an adjustment to the provisional tax benefit recorded under SAB 118 at December 31, 2017. The Company has estimated its provision for income taxes in accordance with the Act and guidance available as of the date of this filing. The Company’s estimated annual effective tax rate may be adjusted in subsequent interim periods, due to, among other things, additional analysis, changes in interpretations and assumptions made by the Company, and additional regulatory guidance that may be issued.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	14. Related Party Transactions In July 2016, the Company entered into a forbearance agreement with HealthpointCapital, LLC, HealthpointCapital Partners, L.P., and HealthpointCapital Partners II, L.P. (collectively, "HealthpointCapital"), pursuant to which HealthpointCapital, on behalf of the Company, paid $1.0 million of the $1.1 million payment due and payable by the Company to Orthotec on July 1, 2016 and agreed to not exercise its contractual rights to seek an immediate repayment of such amount. Pursuant to this forbearance agreement, the Company repaid this amount in September 2016. The Company and HealthpointCapital also entered into an agreement for joint payment of settlement whereby HealthpointCapital has agreed to contribute $5 million to the $49 million Orthotec settlement amount. During the second quarter of 2018, HealthpointCapital Partners, L.P., and HealthpointCapital Partners II, L.P distributed its holdings in the Company’s common stock to its limited partners. As a result, the fund is no longer a shareholder of the Company as of September 30, 2018. The $5 million receivable from HealthpointCapital, LLC continues to be classified within stockholders’ equity on the Company’s condensed consolidated balance sheet due to the related party nature with HealthpointCapital affiliates. Certain of the Company’s board of directors and senior management participated in the March 2017 and 2018 Private Placements.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Restructuring	15. Restructuring In connection with the sale of the International Business (described in Note 4), the Company terminated employment agreements with several executive officers, including the chief executive officer and the chief financial officer, and commenced an employee headcount reduction program. In conjunction with the restructuring program, the Company recorded restructuring expenses related to severance liabilities and post-employment benefits. A rollforward of the accrued restructuring liability is presented below (in thousands): Balance at January 1, 2018 $ 520 Accrued restructuring charges 398 Payments (379 ) Balance at March 31, 2018 539 Accrued restructuring charges 193 Payments (250 ) Balance at June 30, 2018 482 Accrued restructuring charges 167 Payments (313 ) Balance at September 30, 2018 $ 336 All activities and costs are expected to be completed during early 2019. Additionally, on July 6, 2015, the Company announced a restructuring of its manufacturing operations in California in an effort to improve its cost structure. The restructuring included a reduction in workforce and closing the California manufacturing facility in 2017. The Company incurred expenses of $0.1 million and $0.3 million during the three and nine months ended September 30, 2017, respectively, related to these restructuring activities. There was no expense attributed to this transaction for the three and nine months ended September 30, 2018.

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	16. Subsequent Event Equity Plan Amendment As further described in Note 11, on October 25, 2018, the Company’s Board of Directors adopted an amendment to the Company’s 2016 Equity Incentive Award Plan. Credit Agreement with Squadron On November 6, 2018, the Company closed a $35 million Term Loan with Squadron, a provider of debt financing to growing companies in the orthopedic industry. Net proceeds of approximately $33.8 million, after estimated expenses, were used to retire the Company’s existing $29.2 million term debt with Globus. The remainder of the proceeds will be used for general corporate purposes. The debt has a five-year maturity and bears interest at LIBOR plus 8% (currently 10.3%) per annum. Interest-only payments are due monthly through May 2021, followed by $10 million in principal payable in 29 equal monthly installments beginning June 2021 and a $25 million lump-sum payment payable at maturity in November 2023. In connection with the financing, the Company issued warrants to Squadron to purchase 845,000 shares of common stock at an exercise price of $3.15 per share. The warrants have a seven-year term and are immediately exercisable. Termination of Globus Facility Agreement On November 7, 2018, the Company repaid in full all amounts outstanding and due under the Globus Facility Agreement. The Company made a final payment of $29.2 million to Globus, consisting of outstanding principal and accrued interest. Amendment to MidCap Facility Agreement On November 6, 2018, the Company entered into the MidCap Amendment to extend the date that the financial covenants of the MidCap Facility are effective from April 2019 to April 2020, and extended the minimum liquidity covenant through March 2020.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Revenue Recognition	Revenue Recognition The Company recognizes revenue from license and collaboration agreements in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers The adoption of this guidance did not have a material impact on the Company’s consolidated financial statements. The Company derives its revenues primarily from the sale of spinal surgery implants used in the treatment of spine disorders. The Company sells its products primarily through its direct sales force and independent distributors. Revenue is recognized when control of the promised goods are transferred to the customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods. Transfer of control generally occurs when the Company receives the written acknowledgment that the product has been used in a surgical procedure or upon shipment to third-party customers who immediately accept title to such product. The Company’s accounts three
Warrants to Purchase Common Stock	Warrants to Purchase Common Stock Warrants are accounted for in accordance with the applicable accounting guidance as either derivative liabilities or as equity instruments depending on the specific terms of the agreements. As of September 30, 2018, all warrants are classified within stockholders’ equity. The Company periodically evaluates changes in facts and circumstances that could impact the classification of warrants.
Transaction-related Expenses	Transaction-related Expenses The Company expensed certain costs related to the SafeOp acquisition, which primarily include third-party advisory and legal fees .
Fair Value Measurements	Fair Value Measurements T he carrying amount of financial instruments consisting of cash, restricted cash, trade accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses, accrued compensation and current portion of long-term debt included in the Company’s consolidated financial statements are reasonable estimates of fair value due to their short maturities. Based on the borrowing rates currently available to the Company for loans with similar terms, management believes the fair value of long-term debt approximates its carrying value. Authoritative guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Level 2: Level 3: The Company does not maintain any financial assets that are considered to be Level 1, Level 2 or Level 3 instruments as of September 30, 2018. The fair value of the contingent consideration liability assumed in the SafeOp acquisition is recorded as part of the purchase price consideration of the acquisition. using a probability-weighted income approach, utilizing significant unobservable inputs including the probability of achieving each of the potential milestones and an estimated discount rate related to the risks of the expected cash flows attributable to the milestones. The following table provides a reconciliation of liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and nine months ended September 30, 2018 (in thousands): September 30, 2018 Balance at January 1, 2018 $ — Contingent consideration liability recorded upon acquisition of SafeOp 3,200 Change in fair value measurement — Balance at March 31, 2018 3,200 Change in fair value measurement 100 Balance at June 30, 2018 $ 3,300 Settlement of milestone #1 (1,446 ) Change in fair value measurement 546 Balance at September 30, 2018 $ 2,400 During the three months ended September 30, 2018, the Company achieved the first of the two milestones which was settled through the issuance of 443,421 shares of the Company’s common stock. See Note 8 for further information. The material factors that may impact the fair value of the contingent consideration, and therefore, this liability, are the probabilities of achieving the related milestones and the discount rate. Significant increases or decreases in any of the probabilities of success would result in a significantly higher or lower fair value, respectively. Any necessary
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , as modified by subsequently issued ASUs 2015-14, 2016-08, 2016-10, 2016-12 and 2016-20 (collectively “ASU 2014-09”). ASU 2014-09 superseded existing revenue recognition standards with a single model unless those contracts are within the scope of other standards. The revenue recognition principle in ASU 2014-09 is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company adopted the new standard effective January 1, 2018 using the modified retrospective approach applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASU 2014-09, while prior period amounts are not adjusted and continue to be reported in accordance with the historic accounting under ASC 605. The adoption of ASU 2014-09 did not have a material cumulative impact on the Company’s consolidated financial statements as of January 1, 2018. In August 2016, the FASB issued new accounting guidance, which eliminates the diversity in practice related to the classification of certain cash receipts and payments in the statement of cash flows, by adding or clarifying guidance on eight specific cash flow issues. The guidance is effective for annual and interim reporting periods in fiscal years beginning after December 15, 2017, with early adoption permitted. The amendments in this update should be applied retrospectively to all periods presented, unless deemed impracticable, in which case, prospective application is permitted. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business In May 2017, the FASB recently issued ASU 2017-09, Compensation-Stock Compensation , to provide clarity and reduce both 1) diversity in practice and 2) cost and complexity when applying the guidance in Topic 718 to a change in the terms or conditions of a share-based payment award. ASU 2017-09 provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting under Topic 718. The amendments in ASU 2017-09 are effective for fiscal and interim reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period. The amendments in ASU 2017-09 should be applied prospectively to an award modified on or after the adoption date. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Non-Controlling Interests with a Scope Exception. The ASU allows companies to exclude a down round feature when determining whether a financial instrument (or embedded conversion feature) is considered indexed to the entity’s own stock. As a result, financial instruments (or embedded conversion features) with down round features may no longer be required to be classified as liabilities. A company will recognize the value of a down round feature only when it is triggered and the strike price has been adjusted downward. For equity-classified freestanding financial instruments, such as warrants, an entity will treat the value of the effect of the down round, when triggered, as a dividend and a reduction of income available to common shareholders in computing basic earnings per share. For convertible instruments with embedded conversion features containing down round provisions, entities will recognize the value of the down round as a beneficial conversion discount to be amortized to earnings. The guidance in ASU 2017-11 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, and the guidance is to be applied using a full or modified retrospective approach. The Company early adopted the guidance in conjunction with the 2018 Private Placement. In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The Company early adopted the guidance during the second quarter of 2018. The adoption did not have a material cumulative impact on the Company’s consolidated financial statements. Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 , Leases (Topic 842) In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Reconciliation of liabilities measured at fair value using significant unobservable inputs	The following table provides a reconciliation of liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and nine months ended September 30, 2018 (in thousands): September 30, 2018 Balance at January 1, 2018 $ — Contingent consideration liability recorded upon acquisition of SafeOp 3,200 Change in fair value measurement — Balance at March 31, 2018 3,200 Change in fair value measurement 100 Balance at June 30, 2018 $ 3,300 Settlement of milestone #1 (1,446 ) Change in fair value measurement 546 Balance at September 30, 2018 $ 2,400

Select Condensed Consolidated_2

Select Condensed Consolidated Balance Sheet Details (Tables)	9 Months Ended
	Sep. 30, 2018
Balance Sheet Related Disclosures [Abstract]
Accounts receivable, net	Accounts receivable, net consist of the following (in thousands): September 30, 2018 December 31, 2017 Accounts receivable $ 12,391 $ 15,328 Allowance for doubtful accounts (187 ) (506 ) Accounts receivable, net $ 12,204 $ 14,822
Inventories, net	Inventories, net consist of the following (in thousands): September 30, 2018 December 31, 2017 Raw materials $ 5,242 $ 4,969 Work-in-process 548 502 Finished goods 40,095 37,933 45,885 43,404 Less reserve for excess and obsolete finished goods (16,897 ) (16,112 ) Inventories, net $ 28,988 $ 27,292
Property and equipment, net	Property and equipment, net consist of the following (in thousands except as indicated): Useful lives (in years) September 30, 2018 December 31, 2017 Surgical instruments 4 $ 53,372 $ 53,198 Machinery and equipment 7 6,034 5,503 Computer equipment 3 3,813 3,500 Office furniture and equipment 5 2,911 2,794 Leasehold improvements various 1,765 1,714 Construction in progress n/a 92 336 67,987 67,045 Less accumulated depreciation and amortization (55,692 ) (54,375 ) Property and equipment, net $ 12,295 $ 12,670
Intangible assets, net	Intangible assets, net consist of the following (in thousands, except as indicated): Remaining Avg. Useful lives (in years) September 30, 2018 December 31, 2017 Developed technology 12 $ 26,975 $ 13,876 Intellectual property — 1,004 1,004 License agreements — 5,738 5,738 Trademarks and trade names — 792 732 Customer-related 2 7,458 7,458 Distribution network 4 4,027 4,027 In process research and development — 8,550 — 54,544 32,835 Less accumulated amortization (28,199 ) (27,587 ) Intangible assets, net $ 26,345 $ 5,248
Schedule of intangible assets, future amortization expense	Future amortization expense related to intangible assets as of September 30, 2018 is as follows (in thousands): Year Ending December 31, Remainder of 2018 $ 199 2019 1,437 2020 1,432 2021 1,432 2022 1,432 Thereafter 20,413 $ 26,345
Accrued expenses	Accrued expenses consist of the following (in thousands): September 30, 2018 December 31, 2017 Commissions and sales milestones $ 3,121 $ 3,360 Payroll and payroll related 3,692 2,968 Litigation settlement obligation 4,400 4,400 Professional fees 1,901 1,484 Royalties 1,142 1,269 Restructuring and severance accruals 336 520 Taxes 228 246 Guaranteed collaboration compensation, current — 4,485 Interest 576 376 Acquisition related - contingent consideration 2,400 — Other 3,101 3,138 Total accrued expenses $ 20,897 $ 22,246

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Principal Payments on Debt	Principal payments on the Company's debt were as follows as of September 30, 2018 (in thousands): Year Ending December 31, Remainder of 2018 $ 3,922 2019 3,605 2020 3,380 2021 21,667 2022 and thereafter 9,518 Total 42,092 Add: capital lease principal payments 135 Less: unamortized debt discount and debt issuance costs (1,756 ) Total 40,471 Less: current portion of long-term debt (6,186 ) Long-term debt, net of current portion $ 34,285 Credit Agreement with Squadron In November 2018, the Company entered into the Credit Agreement with Squadron for a $35.0 million secured Term Loan. The Term Loan matures over five years and bears interest at the one month LIBOR + 8% per annum. See Note 16 for further information.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Future minimum annual lease payments	Future minimum annual lease payments under such leases are as follows as of September 30, 2018 (in thousands): Year Ending December 31, Operating Capital Remainder of 2018 $ 411 $ 9 2019 1,665 37 2020 1,688 37 2021 1,009 37 2022 and thereafter — 37 $ 4,773 157 Less: amount representing interest (22 ) Present value of minimum lease payments 135 Current portion of capital leases (7 ) Capital leases, less current portion $ 128

Acquisition of SafeOp Surgica_2

Acquisition of SafeOp Surgical, Inc. (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Unaudited Pro Forma Operations	The Merger was accounted for using the acquisition method of accounting. The following unaudited pro forma results of operations assume that the Company acquired Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue $ 23,002 $ 23,153 $ 66,379 $ 75,613 Loss from continuing operations (9,485 ) (4,082 ) (18,952 ) (14,311 ) Net loss $ (9,527 ) $ (4,143 ) $ (19,068 ) $ (14,531 ) Net loss per share, basic and diluted $ (0.22 ) $ (0.21 ) $ (0.46 ) $ (0.93 )
Schedule of Total Purchase Price	The total purchase price is presented below (in thousands): Cash paid and payable $ 15,103 Common stock issued and issuable 10,756 Note 3,000 Warrants 1,650 Contingent Consideration 3,200 Total $ 33,709
Schedule of Allocation of Purchase Price	The allocation of the purchase price to the assets acquired and liabilities assumed based on their fair values, is as follows (in thousands): Assets acquired: Accounts receivable $ 40 Inventory 192 Prepaid expenses and other current assets 89 Total current assets $ 321 Property and equipment, net 20 Other long-term assets 5 IPR&D 8,400 EPAD Tradename 60 Developed Technology 13,100 Total assets $ 21,906 Liabilities assumed: Accounts payable $ 54 Accrued expenses 148 Deferred tax liability 2,341 Total liabilities $ 2,543 Goodwill 14,346 Total consideration transferred $ 33,709

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of basic and diluted net loss per share for continuing and discontinued operations	The following table presents the computation of basic and diluted net loss per share for continuing and discontinued operations (in thousands, except per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Loss from continuing operations $ (9,313 ) $ (3,076 ) $ (18,231 ) $ (11,129 ) Loss from discontinued operations (42 ) (61 ) (116 ) (220 ) Net loss $ (9,355 ) $ (3,137 ) $ (18,347 ) $ (11,349 ) Denominator: Weighted average common shares outstanding 42,497 13,954 32,658 11,400 Weighted average unvested common shares subject to repurchase — (16 ) — (51 ) Weighted average common shares outstanding—basic and diluted 42,497 13,938 32,658 11,349 Net loss per share, basic and diluted: Continuing operations $ (0.22 ) $ (0.22 ) $ (0.56 ) $ (0.98 ) Discontinued operations $ (0.00 ) $ (0.01 ) $ (0.00 ) $ (0.02 ) Net loss per share, basic and diluted $ (0.22 ) $ (0.23 ) $ (0.56 ) $ (1.00 )
Weighted-average anti-dilutive securities not included in diluted net loss per share	The anti-dilutive securities not included in diluted net Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Options to purchase common stock 325 2,948 367 1,861 Unvested restricted share awards — 16 — 51 Series A Convertible Preferred Stock 2,022 4,848 2,181 4,135 Convertible Notes 922 — 703 — Warrants to purchase common stock 1,075 — 1,956 1,013 Total 4,344 7,812 5,207 7,060

Stock Benefit Plans and Equit_2

Stock Benefit Plans and Equity Transactions (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Total Stock Based Compensation	Total stock-based compensation for the three and nine months ended September 30, 2018 and 2017 is as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Cost of revenues $ 18 $ 13 $ 51 $ 27 Research and development 179 (52 ) 192 239 Sales and marketing 223 134 527 358 General and administrative 1,255 355 2,672 1,045 Total $ 1,675 $ 450 $ 3,442 $ 1,669
Summary of Common Stock Reserved for Future Issuance	As of September 30, 2018, the Company had reserved shares of its common stock for future issuance as follows (in thousands): September 30, 2018 Stock options outstanding 4,880 Unvested restricted stock award 3,542 Employee stock purchase plan 232 Series A convertible preferred stock 2,022 Convertible Notes 988 Warrants outstanding 20,932 Distributor and surgeon royalty plans 4,000 Merger contingently issuable 887 Authorized for future grant under the Company equity plans 725 Total 38,208
Summary of Outstanding Warrants	A summary of all outstanding warrants is as follows: Number of Warrants Strike Price 2017 Common Stock Warrants 3,757,000 $ 2.00 2017 Banker Warrants 167,418 $ 2.50 2018 Common Stock Warrants 13,471,851 $ 3.50 Merger Warrants 2,200,000 $ 3.50 Executive 1,327,434 $ 5.00 Other 7,812 $ 19.20 Total 20,931,515

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Rollforward of accrued restructuring liability	A rollforward of the accrued restructuring liability is presented below (in thousands): Balance at January 1, 2018 $ 520 Accrued restructuring charges 398 Payments (379 ) Balance at March 31, 2018 539 Accrued restructuring charges 193 Payments (250 ) Balance at June 30, 2018 482 Accrued restructuring charges 167 Payments (313 ) Balance at September 30, 2018 $ 336

The Company and Basis of Pres_2

The Company and Basis of Presentation - Additional Information (Details)	Nov. 06, 2018USD ($)	Mar. 08, 2018USD ($)	Mar. 31, 2018USD ($)	Sep. 30, 2018USD ($)segment	May 17, 2018shares	Mar. 09, 2018shares	Dec. 31, 2017USD ($)
Company And Basis Of Presentation [Line Items]
Number of reportable segments | segment				1
Proceeds raised from financing transactions			$ 50,000,000
Working capital				$ 44,900,000
Cash				35,111,000			$ 22,466,000
Net proceeds from equity offering				51,600,000
Amended credit facility with MidCap
Company And Basis Of Presentation [Line Items]
Latest date of minimum liquidity covenant		2019-03
Amended credit facility with MidCap | Minimum
Company And Basis Of Presentation [Line Items]
Effective date of financial covenants of amended credit facility		2018-04
Amended credit facility with MidCap | Maximum
Company And Basis Of Presentation [Line Items]
Effective date of financial covenants of amended credit facility		2019-04
Subsequent Event | Amended credit facility with MidCap
Company And Basis Of Presentation [Line Items]
Latest date of minimum liquidity covenant	2020-03
Subsequent Event | Amended credit facility with MidCap | Minimum
Company And Basis Of Presentation [Line Items]
Effective date of financial covenants of amended credit facility	2019-04
Subsequent Event | Amended credit facility with MidCap | Maximum
Company And Basis Of Presentation [Line Items]
Effective date of financial covenants of amended credit facility	2020-04
Term Loan | Squadron Credit Agreement | Subsequent Event
Company And Basis Of Presentation [Line Items]
Secured debt agreement	$ 35,000,000
Line of credit | Globus facility agreement
Company And Basis Of Presentation [Line Items]
Line of credit				29,200,000
Series B Convertible Preferred Stock | Common Stock
Company And Basis Of Presentation [Line Items]
Preferred stock convertible to common stock | shares					14,349,236,000
Private Placement
Company And Basis Of Presentation [Line Items]
Proceeds from private placement			45,200,000
2018 Private Placement
Company And Basis Of Presentation [Line Items]
Proceeds from private placement		$ 45,200,000
Aggregate consideration received from warrant exercise agreement			4,800,000
SafeOp Surgical, Inc.
Company And Basis Of Presentation [Line Items]
Portion of net proceeds from 2018 private placement and warrant exercise used to fund cash portion of purchase price				$ 15,100,000
Preferred stock convertible to common stock | shares						987,578
SafeOp Surgical, Inc. | 2018 Private Placement
Company And Basis Of Presentation [Line Items]
Portion of net proceeds from 2018 private placement and warrant exercise used to fund cash portion of purchase price			$ 15,100,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Accounts receivable payment terms	30 days
Accounts receivable related to products and services	$ 12,204	$ 14,822
Milestones settled through Common Stock Issue	43,153,000	19,857,000
Milestone
Significant Accounting Policies [Line Items]
Milestones settled through Common Stock Issue	443,421

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Liabilities (Details) - Fair value, inputs, level 3 - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 3,300	$ 3,200
Settlement of milestone #1	(1,446)
Change in fair value measurement	546	100
Ending balance	$ 2,400	$ 3,300	$ 3,200
SafeOp Surgical, Inc.
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Contingent consideration liability recorded upon acquisition of SafeOp			$ 3,200

Select Condensed Consolidated_3

Select Condensed Consolidated Balance Sheet Details - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Accounts receivable	$ 12,391	$ 15,328
Allowance for doubtful accounts	(187)	(506)
Accounts receivable, net	$ 12,204	$ 14,822

Select Condensed Consolidated_4

Select Condensed Consolidated Balance Sheet Details - Inventories, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 5,242	$ 4,969
Work-in-process	548	502
Finished goods	40,095	37,933
Inventory, gross, total	45,885	43,404
Less reserve for excess and obsolete finished goods	(16,897)	(16,112)
Inventories, net	$ 28,988	$ 27,292

Select Condensed Consolidated_5

Select Condensed Consolidated Balance Sheet Details - Property and Equipment, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements Captions [Line Items]
Property and equipment, gross	$ 67,987	$ 67,045
Less accumulated depreciation and amortization	(55,692)	(54,375)
Property and equipment, net	$ 12,295	12,670
Surgical instruments
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	4 years
Property and equipment, gross	$ 53,372	53,198
Machinery and equipment
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	7 years
Property and equipment, gross	$ 6,034	5,503
Computer equipment
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	3 years
Property and equipment, gross	$ 3,813	3,500
Office furniture and equipment
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	5 years
Property and equipment, gross	$ 2,911	2,794
Leasehold improvements
Condensed Balance Sheet Statements Captions [Line Items]
Various useful lives of leasehold improvements	various
Property and equipment, gross	$ 1,765	1,714
Construction in progress
Condensed Balance Sheet Statements Captions [Line Items]
Property and equipment, gross	$ 92	$ 336

Select Condensed Consolidated_6

Select Condensed Consolidated Balance Sheet Details - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements Captions [Line Items]
Depreciation	$ 1.5	$ 1.6	$ 4.5	$ 4.8
Amortization of intangible assets	0.2	$ 0.2	0.6	$ 0.7
SafeOp Surgical, Inc.
Condensed Balance Sheet Statements Captions [Line Items]
Business acquisition, intangible assets recorded					$ 21.6
Machinery and equipment
Condensed Balance Sheet Statements Captions [Line Items]
Capital leased assets, gross	$ 2.1		$ 2.1			$ 2.1

Select Condensed Consolidated_7

Select Condensed Consolidated Balance Sheet Details - Intangible Assets, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements Captions [Line Items]
Intangible assets, Gross	$ 54,544	$ 32,835
Less accumulated amortization	(28,199)	(27,587)
Intangible assets, net	$ 26,345	5,248
Developed technology
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	12 years
Intangible assets, Gross	$ 26,975	13,876
Intellectual property
Condensed Balance Sheet Statements Captions [Line Items]
Intangible assets, Gross	1,004	1,004
License agreements
Condensed Balance Sheet Statements Captions [Line Items]
Intangible assets, Gross	5,738	5,738
Trademarks and trade names
Condensed Balance Sheet Statements Captions [Line Items]
Intangible assets, Gross	$ 792	732
Customer-related
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	2 years
Intangible assets, Gross	$ 7,458	7,458
Distribution network
Condensed Balance Sheet Statements Captions [Line Items]
Useful lives	4 years
Intangible assets, Gross	$ 4,027	$ 4,027
In process research and development
Condensed Balance Sheet Statements Captions [Line Items]
Intangible assets, Gross	$ 8,550

Select Condensed Consolidated_8

Select Condensed Consolidated Balance Sheet Details - Schedule of Intangible Assets, Future Amortization Expense (Details) $ in Thousands	Sep. 30, 2018USD ($)
Balance Sheet Related Disclosures [Abstract]
Remainder of 2018	$ 199
2,019	1,437
2,020	1,432
2,021	1,432
2,022	1,432
Thereafter	20,413
Total	$ 26,345

Select Condensed Consolidated_9

Select Condensed Consolidated Balance Sheet Details - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Commissions and sales milestones	$ 3,121			$ 3,360
Payroll and payroll related	3,692			2,968
Litigation settlement obligation	4,400			4,400
Professional fees	1,901			1,484
Royalties	1,142			1,269
Restructuring and severance accruals	336	$ 482	$ 539	520
Taxes	228			246
Guaranteed collaboration compensation, current				4,485
Interest	576			376
Acquisition related - contingent consideration	2,400
Other	3,101			3,138
Total accrued expenses	$ 20,897			$ 22,246

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details)	Sep. 01, 2016USD ($)option	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		$ 23,002,000	$ 23,099,000	$ 66,351,000	$ 75,456,000
Cost of revenues		8,088,000	8,587,000	23,597,000	28,417,000
Globus facility agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Maximum borrowing capacity	$ 30,000,000
Globus facility agreement | Line of credit
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Line of credit, expiration period	5 years
Supply agreement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues			2,300,000		9,200,000
Cost of revenues			$ 2,000,000		$ 7,900,000
Contracts revenue		2,000,000		5,700,000
Cost of contract revenues		$ 1,800,000		$ 5,300,000
Discontinued operations, disposed of by sale | International operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Supply commitment term	3 years
Supply agreement, number of annual options to extend | option	2

Debt - MidCap Facility Agreemen

Debt - MidCap Facility Agreement (Details) - Amended credit facility with MidCap - USD ($)	Nov. 06, 2018	Mar. 08, 2018	Sep. 30, 2018
Line of Credit Facility [Line Items]
Unamortized debt discount			$ 1,100,000
Minimum liquidity covenant amount		$ 5,000,000
Latest date of minimum liquidity covenant		2019-03
Subsequent Event
Line of Credit Facility [Line Items]
Latest date of minimum liquidity covenant	2020-03
Maximum
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility		2019-04
Maximum | Subsequent Event
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility	2020-04
Minimum
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility		2018-04
Minimum | Subsequent Event
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility	2019-04
Line of credit | Maximum
Line of Credit Facility [Line Items]
Debt default, interest rate increase			5.00%
Revolving credit facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 22,500,000
Line of credit			$ 9,500,000
Interest rate			8.10%
Revolving credit facility | LIBOR
Line of Credit Facility [Line Items]
Interest rate description			LIBOR”) plus 6.0%
Basis spread			6.00%
Term Loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 5,000,000

Debt - Globus Facility Agreemen

Debt - Globus Facility Agreement (Details) - Globus facility agreement - USD ($)	Sep. 02, 2018	Sep. 30, 2018	Sep. 01, 2016
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 30,000,000
Unamortized debt discount		$ 600,000
Line of credit
Debt Instrument [Line Items]
Line of credit		29,200,000
Debt instrument, periodic payment		$ 800,000
Line of credit | LIBOR
Debt Instrument [Line Items]
Interest rate description	LIBOR plus 13.0%,	LIBOR plus 8.0%
Basis spread	13.00%	8.00%

Debt - Principal Payments on De

Debt - Principal Payments on Debt (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Debt Disclosure [Abstract]
Remainder of 2018	$ 3,922
2,019	3,605
2,020	3,380
2,021	21,667
2022 and thereafter	9,518
Total	42,092
Add: capital lease principal payments	135
Less: unamortized debt discount and debt issuance costs	(1,756)
Total	40,471
Less: current portion of long-term debt	(6,186)
Long-term debt, net of current portion	$ 34,285

Debt - Credit Agreement with Sq

Debt - Credit Agreement with Squadron (Details) - Squadron Credit Agreement - Subsequent Event $ in Millions	Nov. 06, 2018USD ($)
Term Loan
Line of Credit Facility [Line Items]
Secured debt agreement	$ 35
LIBOR | Line of credit
Line of Credit Facility [Line Items]
Line of credit, expiration period	5 years
Interest rate description	LIBOR plus 8%
Basis spread	8.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Loss Contingencies [Line Items]
Rent expense	$ 300,000	$ 300,000	$ 900,000	$ 900,000
Liability in connection with lawsuit	0		0
Alphatec Spine, Inc.
Loss Contingencies [Line Items]
Guaranteed obligated minimum royalty payments through 2022 and beyond	$ 7,800,000		$ 7,800,000
Minimum
Loss Contingencies [Line Items]
Lease interest rate			6.40%
Maximum
Loss Contingencies [Line Items]
Lease interest rate			7.64%

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Annual Lease Payments (Details) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating leases Remainder of 2018	$ 411
Operating leases 2019	1,665
Operating leases 2020	1,688
Operating leases 2021	1,009
Total Operating leases	4,773
Capital leases Remainder of 2018	9
Capital leases 2019	37
Capital leases 2020	37
Capital leases 2021	37
Capital leases 2022 and thereafter	37
Total Capital leases	157
Less: amount representing interest	(22)
Present value of minimum lease payments	135
Current portion of capital leases	(7)
Capital leases, less current portion	$ 128

Orthotec Settlement - Additiona

Orthotec Settlement - Additional Information (Details)	Jul. 01, 2016USD ($)	Oct. 01, 2014USD ($)	Aug. 13, 2014USD ($)installment	Sep. 30, 2014USD ($)	Apr. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Settlement amount to be contributed							$ 5,000,000	$ 5,000,000
Litigation settlement, remaining outstanding balance including interest							0
Orthotec LLC, litigation settlement
Loss Contingencies [Line Items]
Judgment assessed by court for (against) company			$ 49,000,000
Payments of settlement					$ 15,750,000	$ 1,750,000	35,100,000
Number of quarterly installments | installment			28
Litigation settlement interest, quarterly installments, amount			$ 1,100,000
Litigation settlement, final installment amount			700,000
Litigation settlement, remaining outstanding balance including interest							22,700,000
Orthotec LLC, litigation settlement | HealthpointCapital, LLC
Loss Contingencies [Line Items]
Judgment assessed by court for (against) company				$ 5,000,000
Payments of settlement	$ 1,000,000						1,100,000
Settlement amount to be contributed							$ 5,000,000
Beginning fourth quarter of 2014 | Orthotec LLC, litigation settlement
Loss Contingencies [Line Items]
Settlement amount, remaining balance		$ 31,500,000
Litigation settlement interest, quarterly installments, amount			$ 1,100,000
Litigation settlement interest rate			7.00%
Litigation settlement payments, quarterly payment amount			$ 1,100,000
Final installment | Orthotec LLC, litigation settlement
Loss Contingencies [Line Items]
Number of quarterly installments | installment			1

Acquisition of SafeOp Surgica_3

Acquisition of SafeOp Surgical, Inc. - Additional Information (Details) - USD ($)	Mar. 09, 2018	Mar. 08, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Mar. 31, 2018
Business Acquisition [Line Items]
Accretion to contingent consideration					$ 646,000
Developed SSEP Technology
Business Acquisition [Line Items]
Useful lives					12 years
SafeOp Surgical, Inc.
Business Acquisition [Line Items]
Business acquisition date	Mar. 9, 2018
Increase in net loss due to operating expenses			$ 1,600,000		$ 3,000,000
Cash paid and payable	$ 15,100,000				15,103,000
Cash payment for acquisition					15,100,000
Stock issued for acquisition, value		$ 9,800,000
Closing share price		$ 3.30
Convertible notes issued	$ 3,000,000
Convertible note convertible to common stock	987,578
Number of warrants issued	2,200,000
Exercise price of warrants per share	$ 3.50
Intangible assets						$ 21,600,000
Transaction costs			1,500,000		1,500,000
Additional shares of common stock value issuable subject to performance milestones					4,300,000
Accretion to contingent consideration			500,000		600,000
SafeOp Surgical, Inc. | Ten Days After Submission of an Application for Regulatory Clearance
Business Acquisition [Line Items]
Additional shares of common stock value issuable subject to performance milestones					1,400,000
SafeOp Surgical, Inc. | Ten Days After Receipt of Clearance from Regulatory Authority
Business Acquisition [Line Items]
Additional shares of common stock value issuable subject to performance milestones					2,900,000
SafeOp Surgical, Inc. | EPAD Tradename
Business Acquisition [Line Items]
Intangible assets			60,000		$ 60,000
Useful lives					1 year
SafeOp Surgical, Inc. | Developed SSEP Technology
Business Acquisition [Line Items]
Intangible assets			$ 13,100,000		$ 13,100,000
Useful lives					20 years
SafeOp Surgical, Inc. | Common Stock
Business Acquisition [Line Items]
Stock issued for acquisition	3,265,132	2,975,209	174,302	115,621
SafeOp Surgical, Inc. | Common Stock | Ten Days After Submission of an Application for Regulatory Clearance
Business Acquisition [Line Items]
Stock issued for acquisition			443,421

Acquisition of SafeOp Surgica_4

Acquisition of SafeOp Surgical, Inc. - Schedule of Unaudited Pro Forma Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Abstract]
Revenue	$ 23,002	$ 23,153	$ 66,379	$ 75,613
Loss from continuing operations	(9,485)	(4,082)	(18,952)	(14,311)
Net loss	$ (9,527)	$ (4,143)	$ (19,068)	$ (14,531)
Net loss per share, basic and diluted	$ (0.22)	$ (0.21)	$ (0.46)	$ (0.93)

Acquisition of SafeOp Surgica_5

Acquisition of SafeOp Surgical, Inc. - Schedule of Total Purchase Price (Details) - SafeOp Surgical, Inc. - USD ($) $ in Thousands	Mar. 09, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Cash paid and payable	$ 15,100	$ 15,103
Common stock issued and issuable		10,756
Note		3,000
Warrants		1,650
Contingent Consideration		3,200
Total		$ 33,709

Acquisition of SafeOp Surgica_6

Acquisition of SafeOp Surgical, Inc. - Schedule of Allocation of Purchase Price (Details) - USD ($)	Sep. 30, 2018	Mar. 31, 2018
Liabilities assumed:
Goodwill	$ 14,469,000
SafeOp Surgical, Inc.
Assets acquired:
Accounts receivable	40,000
Inventory	192,000
Prepaid expenses and other current assets	89,000
Total current assets	321,000
Property and equipment, net	20,000
Other long-term assets	5,000
Intangible assets		$ 21,600,000
Total assets	21,906,000
Liabilities assumed:
Accounts payable	54,000
Accrued expenses	148,000
Deferred tax liability	2,341,000
Total liabilities	2,543,000
Goodwill	14,346,000
Total consideration transferred	33,709,000
SafeOp Surgical, Inc. | IPR&D
Assets acquired:
Intangible assets	8,400,000
SafeOp Surgical, Inc. | EPAD Tradename
Assets acquired:
Intangible assets	60,000
SafeOp Surgical, Inc. | Developed technology
Assets acquired:
Intangible assets	$ 13,100,000

Sale of Assets - Additional Inf

Sale of Assets - Additional Information (Details) - USD ($) $ in Thousands	May 05, 2017	Sep. 30, 2017
Sale Of Assets [Line Items]
Net gain on sale of assets		$ 856
Inventory and intellactual property | Third Party
Sale Of Assets [Line Items]
Agreement to sell assets, consideration payable in credit to future minimum royalties owed	$ 1,000
Net gain on sale of assets	$ 900

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share for Continuing and Discontinued Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Loss from continuing operations	$ (9,313)	$ (3,076)	$ (18,231)	$ (11,129)
Loss from discontinued operations	(42)	(61)	(116)	(220)
Net loss	$ (9,355)	$ (3,137)	$ (18,347)	$ (11,349)
Denominator:
Weighted average common shares outstanding	42,497	13,954	32,658	11,400
Weighted average unvested common shares subject to repurchase		(16)		(51)
Weighted average common shares outstanding—basic and diluted	42,497	13,938	32,658	11,349
Net loss per share, basic and diluted:
Continuing operations, net loss per share, basic and diluted	$ (0.22)	$ (0.22)	$ (0.56)	$ (0.98)
Discontinued operations, net loss per share, basic and diluted	0	(0.01)	0	(0.02)
Net loss per share, basic and diluted	$ (0.22)	$ (0.23)	$ (0.56)	$ (1)

Net Loss Per Share - Weighted-A

Net Loss Per Share - Weighted-Average Anti-Dilutive Securities Not Included in Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)	4,344	7,812	5,207	7,060
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)	325	2,948	367	1,861
Unvested restricted share awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)		16		51
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)	1,075		1,956	1,013
Series A Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)	2,022	4,848	2,181	4,135
Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in diluted net loss per share (in shares)	922		703

Stock Benefit Plans and Equit_3

Stock Benefit Plans and Equity Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 08, 2018	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Oct. 25, 2018	May 17, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Warrant outstanding				20,931,515	20,931,515
Stock-based compensation					$ 3,442	$ 1,669
2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Exercise price of warrants (dollars per share)				$ 2	$ 2
Warrant outstanding				3,757,000	3,757,000
Number of warrants exercised				1,500,000	1,900,000
Proceeds from exercise of warrant				$ 3,100	$ 4,000
2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Exercise price of warrants (dollars per share)				$ 2.50	$ 2.50
Warrant outstanding				167,418	167,418
2018 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of warrants issued (in shares)				1,275,000	1,275,000
Exercise price of warrants (dollars per share)				$ 3.50	$ 3.50
Warrant outstanding				13,471,851	13,471,851
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Percentage of outstanding preferred stock shares			75.00%
Number of preferred shares converted					1,274
Number of preferred shares outstanding for being conversion				4,043	4,043
Series A Convertible Preferred Stock | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of preferred shares converted to common stock					636,997
Number of preferred shares outstanding for being conversion to common stock				2,021,673	2,021,673
2017 Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Aggregate gross proceeds for private placement			$ 18,900
2017 Private Placement | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Exercise price of warrants (dollars per share)				$ 2	$ 2
2017 Private Placement | 2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Exercise price of warrants (dollars per share)				$ 2.50	$ 2.50
Warrant outstanding				167,418	167,418
Number of warrants exercised					304,182
Proceeds from exercise of warrant					$ 800
2017 Private Placement | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Issuance of common stock upon securities purchase agreement			1,809,628
Common stock purchase price per share			$ 2
2017 Private Placement | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Preferred stock, shares issued			15,245
Shares issued price per share			$ 1,000
2017 Private Placement | Series A Convertible Preferred Stock | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Preferred stock convertible to common stock			7,622,372
2018 Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Aggregate gross proceeds for private placement	$ 45,200
Exercise price of warrants (dollars per share)	$ 3.50
Proceeds from exercise of warrant		$ 4,800
Warrant expiration period	5 years
2018 Private Placement | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Exercise price of warrants (dollars per share)	$ 2
Warrant outstanding	2,400,000
Number of warrants exercised	1,700,000
Proceeds from exercise of warrant	$ 3,400
Additional proceeds expected to be received from remaining warrant exercises	$ 1,400
Remaining warrant exercisable	700,000
2018 Private Placement | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Preferred stock, shares issued	45,200
Shares issued price per share	$ 1,000
2018 Private Placement | Series A Convertible Preferred Stock | Certificate of Designation
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Preferred stock convertible to common stock	317							14,349,236
Preferred stock, shares authorized	45,200
Preferred stock, stated value per share	$ 1,000
2018 Private Placement | Series A Convertible Preferred Stock | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Preferred stock convertible to common stock	12,617,857
Minimum | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Percentage of outstanding voting stock acquired				50.00%	50.00%
Minimum | 2018 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Percentage of outstanding voting stock acquired				50.00%	50.00%
Maximum | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Beneficial ownership limitation percentage					4.99%
Beneficial ownership, limitation option, percentage					9.99%
Beneficial ownership limitation notification period					61 days
Maximum | 2017 Private Placement | 2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of warrants issued (in shares)				471,600	471,600
Maximum | 2017 Private Placement | Common Stock | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of warrants issued (in shares)				9,432,000	9,432,000
Maximum | 2018 Private Placement | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of warrants issued (in shares)	12,196,851
2016 Equity Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of shares available for grant							500,000
2016 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of shares available for grant							1,250,000
2017 Distributor Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Stock-based compensation				$ 100	$ 200
2017 Distributor Inducement Plan | Board of Directors | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Share authorized grant of warrants									75,000
2017 Distributor Inducement Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Number of warrants issued (in shares)				300,000	300,000
Common stock issued					17,000
2017 Distributor Inducement Plan | Common Stock | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Share authorized grant of warrants									50,000
2018 Development Services Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Share authorized grant of warrants									3,000,000
Share elections, grants or payouts									0

Stock Benefit Plans and Equit_4

Stock Benefit Plans and Equity Transactions - Summary of Total Stock Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Total stock-based compensation	$ 1,675	$ 450	$ 3,442	$ 1,669
Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Total stock-based compensation	18	13	51	27
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Total stock-based compensation	179	(52)	192	239
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Total stock-based compensation	223	134	527	358
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Total stock-based compensation	$ 1,255	$ 355	$ 2,672	$ 1,045

Stock Benefit Plans and Equit_5

Stock Benefit Plans and Equity Transactions - Summary Common Stock Reserved for Future Issuance (Details) shares in Thousands	Sep. 30, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	38,208
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	4,880
Unvested restricted share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	3,542
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	232
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	2,022
Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	988
Warrants Outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	20,932
Distributor and surgeon royalty plans
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	4,000
Merger contingently issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	887
Authorized for future grant under the company equity plans
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	725

Stock Benefit Plans and Equit_6

Stock Benefit Plans and Equity Transactions - Summary of Outstanding Warrants (Details)	Sep. 30, 2018$ / sharesshares
Class Of Warrant Or Right [Line Items]
Number of Warrants	20,931,515
2017 Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	3,757,000
Exercise price of warrants per share | $ / shares	$ 2
2017 Banker Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	167,418
Exercise price of warrants per share | $ / shares	$ 2.50
2018 Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	13,471,851
Exercise price of warrants per share | $ / shares	$ 3.50
Merger Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	2,200,000
Exercise price of warrants per share | $ / shares	$ 3.50
Executive Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	1,327,434
Exercise price of warrants per share | $ / shares	$ 5
Other Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	7,812
Exercise price of warrants per share | $ / shares	$ 19.20

Termination and Settlement of_2

Termination and Settlement of Elite Medical Holdings and Pac 3 Surgical Collaboration Agreement - Additional Information (Details) - Collaborative Arrangement - Elite Medical Holdings and Pac 3 Surgical - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Feb. 28, 2018	Sep. 30, 2018
Termination And Settlement Of Collaboration Agreement [Line Items]
Payments of settlement	$ 0.4
Gain on contract termination and settlement		$ 6.2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Income Tax [Line Items]
Unrecognized tax benefits	$ 4,400,000	$ 4,400,000
Changes in unrecognized tax benefits	0	$ 0
Reasonably possible amount of unrecognized tax benefit that could reverse in the next twelve months	$ 100,000
SafeOp Surgical, Inc.
Income Tax [Line Items]
Effective income tax rate	9.25%
Federal statutory income tax rate	21.00%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	Jul. 01, 2016	Aug. 13, 2014	Sep. 30, 2014	Apr. 30, 2014	Mar. 31, 2014	Sep. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Settlement amount to be contributed						$ 5,000	$ 5,000
Orthotec LLC, litigation settlement
Related Party Transaction [Line Items]
Payments of settlement				$ 15,750	$ 1,750	35,100
Judgment assessed by court for (against) company		$ (49,000)
Orthotec LLC, litigation settlement | HealthpointCapital, LLC
Related Party Transaction [Line Items]
Payments of settlement	$ 1,000					1,100
Judgment assessed by court for (against) company			$ (5,000)
Settlement amount to be contributed						$ 5,000

Restructuring - Rollforward of

Restructuring - Rollforward of accrued restructuring liability (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring And Related Activities [Abstract]
Beginning balance	$ 482	$ 539	$ 520		$ 520
Accrued restructuring charges	167	193	398	$ 139	758	$ 1,898
Payments	(313)	(250)	(379)
Ending balance	$ 336	$ 482	$ 539		$ 336

Restructuring - Additional Info

Restructuring - Additional Information (Details) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 167,000	$ 193,000	$ 398,000	$ 139,000	$ 758,000	$ 1,898,000
2015 California manufacturing operations restructuring plan
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 0			$ 100,000	$ 0	$ 300,000

Subsequent Event - Additional I

Subsequent Event - Additional Information (Details) - USD ($)	Nov. 07, 2018	Nov. 06, 2018	Sep. 02, 2018	Mar. 08, 2018	Sep. 01, 2016	Sep. 30, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Repayments under lines of credit						$ 68,581,000	$ 74,056,000
Amended credit facility with MidCap
Subsequent Event [Line Items]
Latest date of minimum liquidity covenant				2019-03
Amended credit facility with MidCap | Minimum
Subsequent Event [Line Items]
Effective date of financial covenants of amended credit facility				2018-04
Amended credit facility with MidCap | Maximum
Subsequent Event [Line Items]
Effective date of financial covenants of amended credit facility				2019-04
Subsequent Event | Amended credit facility with MidCap
Subsequent Event [Line Items]
Latest date of minimum liquidity covenant		2020-03
Subsequent Event | Amended credit facility with MidCap | Minimum
Subsequent Event [Line Items]
Effective date of financial covenants of amended credit facility		2019-04
Subsequent Event | Amended credit facility with MidCap | Maximum
Subsequent Event [Line Items]
Effective date of financial covenants of amended credit facility		2020-04
Squadron Credit Agreement
Subsequent Event [Line Items]
Current interest rate		10.30%
Squadron Credit Agreement | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, aggregate principal to be paid on installments		$ 10,000,000
Debt instrument, frequency of periodic payment		29 equal monthly installments
Debt instrument payment at maturity		$ 25,000,000
Debt instrument, maturity date		Nov. 30, 2023
Squadron Credit Agreement | Subsequent Event | Common Stock
Subsequent Event [Line Items]
Number of warrants issued (in shares)		845,000
Exercise price of warrants (dollars per share)		$ 3.15
Warrants term		7 years
Term Loan | Squadron Credit Agreement | Subsequent Event
Subsequent Event [Line Items]
Secured debt agreement		$ 35,000,000
Proceeds from secured term loan		$ 33,800,000
Line of credit | Squadron Credit Agreement | Subsequent Event | LIBOR
Subsequent Event [Line Items]
Line of credit, expiration period		5 years
Interest rate description		LIBOR plus 8%
Basis spread		8.00%
Line of credit | Globus facility agreement
Subsequent Event [Line Items]
Line of credit						$ 29,200,000
Line of credit, expiration period					5 years
Line of credit | Globus facility agreement | LIBOR
Subsequent Event [Line Items]
Interest rate description			LIBOR plus 13.0%,			LIBOR plus 8.0%
Basis spread			13.00%			8.00%
Line of credit | Globus facility agreement | Subsequent Event
Subsequent Event [Line Items]
Repayments under lines of credit	$ 29,200,000