NxStage Medical 10-Q 8 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 02, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	NXTM
Entity Registrant Name	NxStage Medical, Inc.
Entity Central Index Key	1,333,170
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,232,226

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 62,979	$ 59,632
Accounts receivable, net	30,245	32,286
Inventory	50,668	46,845
Prepaid expenses and other current assets	8,039	6,136
Total current assets	151,931	144,899
Property and equipment, net	62,212	61,561
Field equipment, net	23,793	22,309
Deferred cost of revenues	31,125	33,165
Intangible assets, net	8,169	9,688
Goodwill	42,748	42,648
Other assets	5,376	2,937
Total assets	325,354	317,207
Current liabilities:
Accounts payable	12,871	14,177
Accrued expenses	28,625	30,985
Current portion of long-term debt	99	328
Other current liabilities	4,602	3,770
Total current liabilities	46,197	49,260
Deferred revenues	47,422	49,001
Long-term debt	551	1,305
Other long-term liabilities	17,994	15,568
Total liabilities	112,164	115,134
Commitments and contingencies (Notes 1 and 10)
Noncontrolling interests subject to put provisions	650	50
Stockholders’ equity:
Undesignated preferred stock: par value $0.001, 5,000,000 shares authorized; no shares issued and outstanding as of September 30, 2017 and December 31, 2016	0	0
Common stock: par value $0.001, 100,000,000 shares authorized; 67,231,121 and 65,883,026 shares issued as of September 30, 2017 and December 31, 2016, respectively	67	65
Additional paid-in capital	653,431	631,219
Accumulated deficit	(419,324)	(407,601)
Accumulated other comprehensive loss	(1,895)	(6,101)
Treasury stock, at cost: 1,034,188 and 936,360 shares as of September 30, 2017 and December 31, 2016, respectively	(18,955)	(16,184)
Total NxStage Medical, Inc. stockholders' equity	213,324	201,398
Noncontrolling interests not subject to put provisions	(784)	625
Total stockholders' equity	212,540	202,023
Total liabilities and stockholders’ equity	$ 325,354	$ 317,207

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Undesignated preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Undesignated preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Undesignated preferred stock, shares issued (in shares)	0	0
Undesignated preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	67,231,121	65,883,026
Treasury stock, shares (in shares)	1,034,188	936,360

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Revenues	$ 97,295	$ 91,951	$ 290,340	$ 273,365
Cost of revenues	56,688	52,770	167,377	159,244
Gross profit	40,607	39,181	122,963	114,121
Operating expenses:
Selling and marketing	16,984	16,024	50,595	47,394
Research and development	11,222	8,278	29,757	23,393
Distribution	8,065	7,063	23,394	21,131
General and administrative	12,619	7,792	31,237	24,334
Total operating expenses	48,890	39,157	134,983	116,252
(Loss) income from operations	(8,283)	24	(12,020)	(2,131)
Other expense:
Interest expense, net	(168)	(244)	(595)	(773)
Other income (expense), net	26	(346)	(565)	(987)
Total other expense	(142)	(590)	(1,160)	(1,760)
Net loss before income taxes	(8,425)	(566)	(13,180)	(3,891)
Provision for (benefit from) income taxes	469	324	(166)	1,007
Net loss	(8,894)	(890)	(13,014)	(4,898)
Less: Net loss attributable to noncontrolling interests	(449)	(724)	(1,291)	(1,724)
Net loss attributable to NxStage Medical, Inc.	(8,445)	(166)	(11,723)	(3,174)
Less: Accretion to redemption value of noncontrolling interests	(481)	0	(481)	0
Net loss attributable to common stockholders	$ (8,926)	$ (166)	$ (12,204)	$ (3,174)
Net loss per share, basic and diluted (in dollars per share)	$ (0.14)	$ 0	$ (0.19)	$ (0.05)
Weighted-average shares outstanding, basic and diluted (in shares)	66,082	64,638	65,723	64,414
Other comprehensive (loss) income:
Unrealized (loss) income on derivative instruments, net of income taxes	$ (661)	$ (5)	$ 2,376	$ 92
Other income (loss)	268	(73)	1,830	(389)
Total other comprehensive (loss) income	(393)	(78)	4,206	(297)
Total comprehensive loss	(9,287)	(968)	(8,808)	(5,195)
Less: Comprehensive loss attributable to noncontrolling interests	(449)	(724)	(1,291)	(1,724)
Total comprehensive loss attributable to NxStage Medical, Inc.	$ (8,838)	$ (244)	$ (7,517)	$ (3,471)

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net loss	$ (13,014)	$ (4,898)
Adjustments to reconcile net loss to net cash flow from operating activities:
Depreciation and amortization	25,321	23,974
Stock-based compensation	8,684	7,688
Other	1,183	(886)
Changes in operating assets and liabilities:
Accounts receivable	2,443	(5,501)
Inventory	(18,154)	(22,026)
Prepaid expenses and other assets	604	621
Accounts payable	(1,886)	3,930
Accrued expenses and other liabilities	(1,286)	3,015
Deferred revenues	(1,906)	(924)
Net cash provided by operating activities	1,989	4,993
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(100)	(513)
Purchase of cost method investment	(2,500)	0
Purchases of property and equipment	(7,550)	(6,796)
Net cash used in investing activities	(10,150)	(7,309)
Cash flows from financing activities:
Issuance of shares under stock incentive plans, net of payroll taxes paid	11,019	3,677
Investment by noncontrolling interest holder	0	1,210
Proceeds from loans, lines of credit and capital lease obligations	452	0
Repayments on loans and lines of credit	(126)	(225)
Repayments on capital leases	(981)	(1,153)
Net cash provided by financing activities	10,364	3,509
Foreign exchange effect on cash and cash equivalents	1,144	559
Increase in cash and cash equivalents	3,347	1,752
Cash and cash equivalents, beginning of period	59,632	59,065
Cash and cash equivalents, end of period	$ 62,979	$ 60,817

Nature of Operations, Proposed

Nature of Operations, Proposed Merger, Basis of Presentation and Principles of Consolidation	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Nature of Operations, Proposed Merger Agreement, Basis of Presentation and Principles of Consolidation	Nature of Operations, Proposed Merger, Basis of Presentation and Principles of Consolidation Nature of Operations We are a medical technology company that develops, manufactures and markets innovative products and services for patients suffering from chronic or acute kidney failure. Our primary product, the System One, was designed to satisfy an unmet clinical need for a system capable of delivering the therapeutic flexibility and clinical benefits of traditional dialysis machines in a smaller, portable, easy-to-use form that can be used by healthcare professionals and trained lay users alike in a variety of settings, including patient homes and home-like settings, including skilled nursing facilities, as well as more traditional care settings such as hospitals and dialysis centers. Given its design, the System One is particularly well-suited for home hemodialysis and a range of dialysis therapies that are more practical to deliver in the home setting, including more frequent hemodialysis and nocturnal hemodialysis. Clinical literature suggests such therapies provide patients better clinical outcomes and improved quality of life. In addition to the System One, we provide patients with our PureFlow SL accessory which prepares on-site premixed dialysate fluid in the patient's home using ordinary tap water and dialysate concentrate. We also operate a small number of NxStage Kidney Care dialysis centers, independently and in some instances as joint ventures, that treat end-stage renal disease (ESRD) patients directly. These centers provide us with valuable experience to better meet and anticipate the needs of both our customers and patients, while optimizing our product technology. In addition, these centers provide us with the opportunity to innovate and foster new care delivery models to advance the standard of renal care across other markets. More specifically, at NxStage Kidney Care we offer a range of treatment options, including home hemodialysis, peritoneal dialysis and flexible in-center hemodialysis. These centers also help us to devise best practices for successful home dialysis programs and provide sites for future clinical trials of our products. We are headquartered in Lawrence, Massachusetts, with manufacturing facilities in Mexico, Germany and Italy. Through our international network of affiliates and distribution partners, patients in over 21 countries have been treated with our products. Proposed Merger On August 7, 2017, we entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Fresenius Medical Care Holdings, Inc. (“Fresenius”), pursuant to which we will merge with a wholly-owned subsidiary of Fresenius, subject to certain conditions. At the closing of the merger, all outstanding shares of our common stock (except those held by us, Fresenius or its wholly-owned subsidiaries or any stockholders properly exercising their appraisal rights under the General Corporation Law of the State of Delaware) would be converted into the right to receive $30.00 per share in cash, subject to any applicable tax withholdings. The closing of the merger is conditioned, among other things, on receipt of regulatory approval under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the "HSR Act") or the expiration or termination of the applicable waiting periods (and any extension thereof) under the HSR Act and other customary closing conditions. Immediately prior to, and contingent upon, closing, each outstanding Company stock option, restricted stock unit, restricted share and performance share (collectively, the “Company Equity Awards”) will vest in full (with applicable performance conditions deemed satisfied at maximum levels). Such fully vested Company Equity Awards will be canceled and converted into cash at $30.00 per share for each share of our common stock underlying such Company Equity Awards (net of any applicable exercise price and subject to any applicable withholding tax). The Merger Agreement may be terminated by us or Fresenius if it is not closed by August 7, 2018 (the “End Date”), although Fresenius may extend the End Date for up to 180 days under certain circumstances in order to obtain required antitrust clearances. The Merger Agreement generally requires each party to use its reasonable best efforts to obtain all consents and clearances required under any antitrust law, except that Fresenius is not required (i) to litigate against a governmental entity or (ii) to divest or to take any other actions with respect to any assets or business of Fresenius, its subsidiaries or the Company, other than, if necessary to obtain antitrust clearances, with respect to certain Company assets. Fresenius is required to pay us a termination fee of $100 million (the “Reverse Termination Fee”) if the Merger Agreement is terminated by us or Fresenius (i) if the End Date and any applicable extension has passed or (ii) if a court or other governmental entity issues a final, nonappealable order or takes any other actions that permanently prohibits the merger or makes closing the merger illegal (in each case because approval under applicable antitrust laws remains the only unsatisfied closing condition). We would be required to pay Fresenius a termination fee of $60 million (the “Termination Fee”) if all of the following conditions were applicable: (i) the Merger Agreement is terminated because the End Date has passed or we have breached a representation or warranty, (ii) an alternative acquisition proposal has been publicly made and not publicly withdrawn at least ten days prior to the termination, and (iii) within 12 months following such termination, we enter into an alternative acquisition agreement or an alternative acquisition is consummated. Nonetheless, we will not be required to pay the Termination Fee if the Merger Agreement is terminated due to failure to obtain required antitrust approvals by the End Date and Fresenius is required to pay the Reverse Termination Fee. The Merger Agreement includes customary representations, warranties and covenants of the Company and Fresenius. Pursuant to the Merger Agreement, we agreed to use commercially reasonable efforts to operate our business in all material respects in the ordinary course until closing. On October 27, 2017, the stockholders of NxStage Medical, Inc. voted to approve the merger agreement. In addition, the merger has cleared antitrust review in Germany. See “Risk Factors” in Part II Item 1A of this Quarterly Report for additional information. Basis of Presentation The accompanying condensed consolidated financial statements as of September 30, 2017 and December 31, 2016 and for the three and nine months ended September 30, 2017 and 2016 , and related notes, are unaudited but, in the opinion of our management, include all adjustments, consisting of normal recurring adjustments, that are necessary for fair statement of the interim periods presented. Our unaudited condensed consolidated financial statements have been prepared following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under these rules, we have condensed or omitted certain footnotes and other financial information that are normally required by U.S. generally accepted accounting principles (GAAP). Our accounting policies are described in the notes to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2016 ( 2016 Annual Report) and updated, as necessary, in this Quarterly Report on Form 10-Q (Quarterly Report). Operating results for any interim period are not necessarily indicative of results for the entire year or future periods. The December 31, 2016 condensed consolidated balance sheet contained herein was derived from audited financial statements, but does not include all disclosures that would be required for audited financial statements under GAAP. For further information, refer to the consolidated financial statements and footnotes thereto included in our 2016 Annual Report. The preparation of our condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Such financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments are of a normal recurring nature. Principles of Consolidation Our condensed consolidated financial statements include the accounts of NxStage Medical, Inc. and our wholly-owned subsidiaries and other entities in which we maintain a majority voting interests or for which we maintain effective control, including variable interest entities ("VIEs") for which we are deemed the primary beneficiary. All significant intercompany balances and transactions have been eliminated. Noncontrolling interests represent the proportionate equity interests in the consolidated entities that are not wholly owned by us. Noncontrolling interests of acquired entities are recognized at their initial fair value.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Concentration of Credit Risk Concentration of credit risk with respect to accounts receivable is primarily limited to certain customers to whom we make substantial sales. No customer represented more than 10% of accounts receivable at September 30, 2017 . Two customers represented 12% and 10% of accounts receivable at December 31, 2016 . Warranty Costs We accrue estimated costs that we may incur under our product warranty programs at the time the product revenue is recognized, based on contractual rights and historical experience. Warranty expense is included in cost of revenues in the condensed consolidated statements of comprehensive loss. The following is a rollforward of our warranty accrual (in thousands): Balance at December 31, 2016 $ 280 Provision 317 Usage (328 ) Balance at September 30, 2017 $ 269 Intangibles and Other Long-Lived Assets Intangible assets are carried at cost less accumulated amortization. For assets with determinable useful lives, amortization is recognized using the straight-line method over the estimated economic lives of the respective intangible assets. Long-lived assets, including intangible assets, are evaluated for recoverability whenever events or circumstances indicate that their carrying value may not be recoverable. Recoverability of long-lived assets is assessed at the lowest level for which discrete cash flows are available and is measured by comparing the asset group’s carrying value to its expected non-discounted future cash flows. If the sum of the expected non-discounted future cash flows is less than the carrying amount of the long-lived assets, an impairment loss is recognized for excess of the carrying amount of the asset group over its fair value. In 2017, events and circumstances have indicated that certain long-lived tangible assets in the Services segment may not be recoverable. Therefore, a recoverability test was performed at the center level by comparing the carrying value of each center to its estimated future undiscounted cash flows, within the initial lease term (which is the equivalent to the depreciable life of the centers' most significant asset, its leasehold improvements). As of September 30, 2017, our expected non-discounted future cash flows for the majority of our centers indicated such carrying amounts were expected to be recovered. No impairment charge was recognized during the third quarter of 2017. We recorded an impairment charge during the second quarter of 2017 of $0.3 million in cost of revenue to write-down certain center level assets within our Services segment. Our expected non-discounted future cash flows used in our impairment testing are based upon cash flow projections and, if appropriate, include assumed proceeds upon sale of the asset group at the end of the cash flow period. We believe our procedures for developing cash flow projections, including the estimated sales proceeds, are reasonable and consistent with current market conditions for each of the dates when impairment testing has been performed. Developing cash flow projections requires significant estimates and judgment. Among other things, slower than expected patient ramp or lower than expected reimbursement rates would negatively impact our cash flow projections in the near term. We had $15.0 million of long-lived assets at our Services segment at September 30, 2017. It is reasonably possible that our cash flow projections may change in the near term resulting in the need to record an impairment charge for at least some portion of these assets. Goodwill We test goodwill for impairment during the fourth quarter, or more frequently when events or changes in circumstances indicate that the goodwill might be impaired. This test includes first a qualitative assessment and then, if necessary, a quantitative assessment to determine if the fair value of a reporting unit is less than its carrying amount. Our System One, In-center and Services reporting units contain goodwill of $41.1 million , $0.5 million and $1.1 million , respectively. Factors considered in the qualitative assessment include, but are not limited to, both macroeconomic conditions and entity-specific conditions. For the quantitative assessment the reporting unit's fair value is estimated using a discounted cash flow or other fair value measurement. During 2016 and 2015 we utilized the qualitative assessment to assess the fair value of our System One and In-center reporting units and concluded that it was more likely than not that the fair value of our reporting units was greater than their carrying value. During 2016, for our Services reporting unit, we utilized the quantitative assessment noting that the fair value of the reporting unit exceeds its carrying value, indicating that goodwill was not impaired. We estimated the fair value of our Services reporting unit using a discounted cash flow approach. There have been no events or changes in circumstances since the date of our last goodwill impairment tests that would indicate it is more likely than not that the fair value of our reporting units is less than their carry value. Our Services reporting unit, with a goodwill of $1.1 million at September 30, 2017 , has been identified as having a higher risk for impairment. Future events that could have a negative impact on the levels of excess fair value over carrying value of our Services reporting unit include, but are not limited to, changes in discount rates, slower than expected patient ramp, lower than expected reimbursement rates or operating income, increases in capital expenditures or unfavorable changes in working capital. Negative changes in one or more of these factors, among others, could results in a goodwill impairment charge of up to $1.1 million in the future. Recent Accounting Pronouncements Recently Implemented Accounting Pronouncements In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): "Simplifying the Measurement of Inventory." The update requires that an entity should measure in scope inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments were effective for us beginning January 1, 2017. The adoption of this update did not have a material impact on our financial statements. In March 2016, the FASB issued ASU No. 2016-09: “Improvements to Employee Share-Based Payment Accounting,” which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The new guidance was effective for us beginning January 1, 2017. We have elected to continue to estimate forfeiture rates. This new standard impacts our income tax footnote disclosures. We have tax effected federal net operating losses of $18.0 million and state net operating losses of $1.6 million that are attributable to excess tax deductions related to stock-based compensation from prior years. Upon adoption the cumulative excess tax deductions related to stock-based compensation that were previously unrecognized are being recognized as a deferred tax asset and are fully offset by a valuation allowance. Other than this change in our income tax footnote disclosures, the adoption does not have a material impact on our financial statements. In January 2017, the FASB issued ASU No. 2017-04: "Intangibles - Goodwill and Other Topics (Topic 350): Simplifying the Test for Goodwill Impairment". The purpose of this update is to reduce the cost and complexity of evaluating goodwill for impairment. It eliminates the need for entities to calculate the impaired fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. Under this update, an entity will perform its goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge is recognized for the amount by which the carrying value exceeds the reporting unit's fair value. We elected to early adopt this update on a prospective basis for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this update did not have a material impact on our financial statements. In May 2017, the FASB issued ASU No. 2017-09: "Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting". The purpose of this update is to reduce the diversity in practice and result in fewer changes to the terms of an award being accounted for as modifications. It will allow companies to make non-substantive changes to their share-based payment awards, without accounting for them as modifications. It does not change the accounting for modifications. Under this update, an entity will apply the modification accounting guidance only if the value (or calculated value or intrinsic value, if those measurement methods are used), vesting conditions or classification of the award as an equity or liability instrument changes. This update also clarifies that a modification to an award could be significant and therefore require disclosure, even if modification accounting is not required. The new guidance will be applied prospectively to awards modified on or after the adoption date. We elected to early adopt this update in the second quarter of 2017. The adoption of this update did not have a material impact on our financial statements. Recent Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-9: “Revenue from Contracts with Customers.” The standard provides that revenue should be recognized when an entity transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenues and cash flow arising from contracts with customers. The FASB has issued several amendments and updates to the new revenue standard, including how an entity should identify performance obligations. As amended, the new guidance is effective for us beginning January 1, 2018. The new guidance allows for full retrospective adoption applied to all periods presented or a modified retrospective adoption with the cumulative effect of initially applying the new guidance recognized at the date of initial application. In 2016, we commenced our evaluation of the impact of the standard, by establishing a cross functional team and evaluating the anticipated impact on significant contracts from each of our business segments. We intend to use the modified retrospective adoption methodology. We are evaluating the potential impact of the standard on the related disclosures and are comparing our current policies and practices to the requirements of the standard. We have developed a project plan to develop processes and tools and to assess the internal control structure in order to adopt the standard on January 1, 2018. We believe that the standard will impact the timing of revenue recognition for our Services segment as the standard eliminates cash basis revenue recognition and instead requires revenues to be estimated and recognized upon transfer of the promised goods and services. The adoption of the standard is not expected to have a material impact on our other segments. We have periodically briefed our Audit Committee on our progress made towards adoption. Based on our evaluation to date, we anticipate being able to estimate the quantitative impacts of adopting the ASU in connection with the filing of our 2017 Form 10-K. In February 2016, the FASB issued ASU No. 2016-02: "Accounting for Leases" which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than twelve months. For lessees, leases will continue to be classified as either operating or financing in the income statement. This ASU is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The new guidance is effective for us beginning January 1, 2019 and early adoption is permitted. We intend to adopt this standard as of January 1, 2019. We are currently evaluating the potential impact this standard will have on our financial statements. In January 2017, the FASB issued ASU No. 2017-01: "Business Combinations (Topic 805): Clarifying the Definition of a Business" which changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. The update is effective for us beginning January 1, 2018. Early adoption is permitted, including for interim or annual periods in which the financial statements have not been issued or made available for issuance. The adoption of this update is not expected to have a material impact on our financial statements.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2017
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory includes material, labor and overhead, and is stated at lower of cost (first-in, first-out) or market. The components of inventory are as follows (in thousands): September 30, December 31, Purchased components $ 14,861 $ 14,967 Work in process 14,891 13,939 Finished goods 20,916 17,939 Total $ 50,668 $ 46,845

Property and Equipment and Fiel

Property and Equipment and Field Equipment	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment, and Field Equipment	Property and Equipment, and Field Equipment Accumulated depreciation on property and equipment was $57.3 million and $47.2 million at September 30, 2017 and December 31, 2016 , respectively. Accumulated depreciation on field equipment was $52.5 million and $48.4 million at September 30, 2017 and December 31, 2016 , respectively.

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets Accumulated amortization of intangible assets was $26.5 million and $25.0 million at September 30, 2017 and December 31, 2016 , respectively.

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic net loss per share is computed by dividing loss attributable to NxStage Medical, Inc. common stockholders (the numerator) by the weighted-average number of common shares outstanding (the denominator) for the period. The computation of diluted loss per share is similar to basic loss per share, except that the denominator is increased to include the number of additional common shares that would have been outstanding if the potentially dilutive common shares had been issued. The following potential common stock equivalents, as calculated using the treasury stock method, were not included in the computation of diluted net loss per share as their effect would have been anti-dilutive due to the net loss incurred (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Options to purchase common stock 1,069 1,096 1,126 682 Unvested restricted stock 327 382 238 359 Total 1,396 1,478 1,364 1,041

Accrued Expenses, Other Current

Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities	9 Months Ended
	Sep. 30, 2017
Payables and Accruals [Abstract]
Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities	Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities The components of accrued expenses are as follows (in thousands): September 30, December 31, Payroll, compensation and related benefits $ 12,637 $ 14,086 Distribution expenses 5,132 4,804 General and administrative expenses 1,830 4,415 Audit, legal and consulting fees 3,469 1,373 Other manufacturing costs 1,481 1,891 Other 4,076 4,416 Total $ 28,625 $ 30,985 The components of other current liabilities are as follows (in thousands): September 30, December 31, Capital lease obligations $ 2,154 $ 1,840 Deferred revenue, current portion 1,526 1,035 Other 922 895 Total $ 4,602 $ 3,770 The components of other long-term liabilities are as follows (in thousands): September 30, December 31, Capital lease obligations $ 11,595 $ 9,991 Lease incentive obligations 2,842 3,059 Benefit plan obligations 2,020 1,678 Other 1,537 840 Total $ 17,994 $ 15,568

Debt and Capital Lease Obligati

Debt and Capital Lease Obligations	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt and Capital Lease Obligations	Debt and Capital Lease Obligations Other Loan In May 2017, we extinguished a loan with a balance of $0.9 million and simultaneously entered into a capital lease of certain property and equipment for the same amount. The capital lease obligation is payable over five years . This debt extinguishment and capital lease financing represent a noncash investing and financing activity.

Segment Disclosures

Segment Disclosures	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Disclosures	Segment Disclosures We have three reportable business segments: System One, In-Center, and Services. The operating results of NxStage Kidney Care are included in our Services segment. We refer to our System One segment, In-Center segment, and Other category as our products business. Our System One segment includes revenues from sales of the System One and PureFlow SL dialysate preparation equipment and sales of disposable products to customers in the home market, including through our NxStage Kidney Care dialysis centers, and critical care market. The home market is devoted to the treatment of ESRD patients in the home or a home-like setting, including skilled nursing facilities, while the critical care market is devoted to the treatment of hospital-based patients with acute kidney failure or fluid overload. Some of our largest customers in the home market provide outsourced renal dialysis services to some of our customers in the critical care market. Sales of product to both markets are made primarily through dedicated sales forces and distributed directly to the customer, or the patient, with certain products sold through distributors. Our In-Center segment includes revenues from the sale of blood tubing sets and needles for hemodialysis primarily for the treatment of ESRD patients at dialysis centers and needles for apheresis. Nearly all In-Center products are sold through national distributors. The remainder of our products business, which is included within the Other category, relates to the manufacturing of dialyzers for sale to Asahi Kasei Kuraray Medical Co., Ltd. (Asahi) and research and development and general and administrative expenses that are excluded from the segment operating performance measures. Our Services segment includes revenues from dialysis services provided to patients at our NxStage Kidney Care dialysis centers. Sales of the System One and related products to our NxStage Kidney Care dialysis centers are included in System One segment revenues, which are then eliminated upon consolidation. The accounting policies of our reportable segments are described in Note 2 to the consolidated financial statements included in our 2016 Annual Report and updated, as necessary, in Note 2 to the condensed consolidated financial statements included in this Quarterly Report. Our chief operating decision maker allocates resources to our business segments and assesses segment performance based on segment profit (loss), which consists of revenues less cost of revenues, selling and marketing and distribution expenses. The following summarizes the operating performance of our reportable segments (in thousands): System One In-Center Other Services Intersegment Elimination Total Three Months Ended September 30, 2017 Revenues from external customers $ 73,479 $ 15,465 $ 3,392 $ 4,959 $ — $ 97,295 Intersegment revenues 1,197 — — — (1,197 ) — Revenues 74,676 15,465 3,392 4,959 (1,197 ) 97,295 Segment profit (loss) 18,799 2,131 (23,602 ) (5,626 ) 15 (8,283 ) Depreciation and amortization 5,539 564 1,088 1,318 (26 ) 8,483 Three Months Ended September 30, 2016 Revenues from external customers $ 70,011 $ 14,493 $ 3,601 $ 3,846 $ — $ 91,951 Intersegment revenues 1,930 — — — (1,930 ) — Revenues 71,941 14,493 $ 3,601 3,846 (1,930 ) 91,951 Segment profit (loss) 19,828 2,463 (15,676 ) (6,384 ) (207 ) 24 Depreciation and amortization 6,015 500 1,134 1,232 (556 ) 8,325 Nine Months Ended September 30, 2017 Revenues from external customers $ 220,950 $ 45,397 $ 9,127 $ 14,866 $ — $ 290,340 Intersegment revenues 3,845 — — — (3,845 ) — Revenues 224,795 45,397 9,127 14,866 (3,845 ) 290,340 Segment profit (loss) 60,021 6,152 (60,445 ) (17,724 ) (24 ) (12,020 ) Depreciation and amortization 16,601 1,633 3,252 3,888 (53 ) 25,321 Nine Months Ended September 30, 2016 Revenues from external customers $ 205,538 $ 47,990 $ 9,190 $ 10,647 $ — $ 273,365 Intersegment revenues 5,553 — — — (5,553 ) — Revenues 211,091 47,990 $ 9,190 10,647 (5,553 ) 273,365 Segment profit (loss) 55,997 8,155 (46,332 ) (19,354 ) (597 ) (2,131 ) Depreciation and amortization 17,362 1,489 3,361 3,441 (1,679 ) 23,974 Substantially all of our revenues are derived from the sale of the System One and related products, which cannot be used with any other dialysis system, and from needles and blood tubing sets in the U.S. The following table summarizes the number of customers who individually make up greater than ten percent of total revenues: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 DaVita 20 % 21 % 20 % 20 % Fresenius 20 % 18 % 19 % 18 % Sales to DaVita HealthCare Partners Inc. (DaVita) and Fresenius Medical Care (Fresenius) are in the System One segment.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Significant commitments and contingencies at September 30, 2017 are consistent with those discussed in Note 10 to the consolidated financial statements in our 2016 Annual Report.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We recognized a provision for income taxes during both the three and nine months ended September 30, 2017 and 2016 related to the profitable operations of certain foreign subsidiaries. However, the provision recognized during 2017 includes the impact of an allocation of U.S. tax expense between continuing operations and total other comprehensive (loss) income. Such allocation resulted in an increase to the provision for income taxes of $0.1 million during the three months ended September 30, 2017 and a decrease to the provision for income taxes of $1.1 million during the nine months ended September 30, 2017. This allocation has no impact on total comprehensive loss or total stockholders' equity for 2017. However, it did result in a net tax benefit from income taxes in continuing operations of $0.2 million during the nine months ended September 30, 2017. As of September 30, 2017 , we had a liability for unrecognized tax benefits included in the balance sheet of approximately $0.8 million , including a nominal accrual for interest and penalties of less than $0.1 million . There have been no significant changes to these amounts during the three and nine months ended September 30, 2017 .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock-based Compensation Expense The following table presents stock-based compensation expense included in our condensed consolidated statements of comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Cost of revenues $ 335 $ 314 $ 902 $ 1,056 Selling and marketing 1,054 781 3,047 2,562 Research and development 437 344 1,154 1,148 General and administrative 1,534 855 3,581 2,922 Total $ 3,360 $ 2,294 $ 8,684 $ 7,688 Stock Options and Restricted Stock Units The Company granted options to purchase 7,480 and 20,351 shares of common stock during the three months ended September 30, 2017 and 2016 , respectively, and options to purchase 675,358 and 1,334,351 shares of common stock during the nine months ended September 30, 2017 and 2016 , respectively, which vest based on continued employment over a period of one to four years. The weighted-average fair value of options granted during the nine months ended September 30, 2017 and 2016 was $9.92 and $5.89 per option, respectively. The Company awarded 20,970 and 23,380 restricted stock units during the three months ended September 30, 2017 and 2016 , respectively, and 175,895 and 219,846 restricted stock units during the nine months ended September 30, 2017 and 2016 , respectively, which vest based on continued employment over a period of three to four years. The weighted-average fair value of these restricted stock units awarded during the nine months ended September 30, 2017 and 2016 was $27.23 and $17.34 per unit, respectively. In March 2017 , the Compensation Committee of our Board of Directors approved the grant of up to 231,384 restricted stock units subject to the achievement of certain Company financial performance metrics for the year ending December 31, 2017 . In August 2017, in connection with the Board of Director's approval of the Merger Agreement, the Compensation Committee determined that all Company financial performance metric criteria shall be deemed fully satisfied. The restricted stock units vest over a requisite service period of three years and have a modified grant date fair value of $23.14 per unit.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity We received 97,828 and 100,571 shares of common stock that were surrendered in payment for the exercise of stock options during the nine months ended September 30, 2017 and 2016 , respectively.

Noncontrolling Interest

Noncontrolling Interest	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest As of September 30, 2017 , we have 5 VIEs included in our consolidated financial statements all of which are NxStage Kidney Care dialysis centers. We are the managing member or we have a majority seat on the entity’s board of managers, manage these entities through a management services agreement, and provide operating and capital funding as necessary for the entities to accomplish their operational and strategic objectives which transfer substantial power over and economic responsibility for the entities to us. The analysis upon which these consolidation determinations rest are complex, involve uncertainties, and require significant judgment on various matters. At September 30, 2017 and December 31, 2016 , total assets of our VIEs were $5.8 million and $8.0 million , and total liabilities and noncontrolling interests of our VIEs were $5.9 million and $7.2 million , respectively. We have potential obligations to purchase the noncontrolling interests held by third parties in certain of our consolidated subsidiaries. These obligations are in the form of put provisions and are contingently exercisable at the third-party owners' discretion given specific facts and circumstances as outlined in each specific put provision. If these put provisions were exercised, we would be required to purchase all the third-party owners' noncontrolling interests at a fair value at the time of exercise pursuant to the terms of the agreement. At September 30, 2017 the Company's noncontrolling interests subject to put provisions were $0.7 million and none of the rights were exercisable. The following table sets forth the changes in noncontrolling interest not subject to put provisions for the three and nine months ended September 30, 2017 and 2016 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Balance at beginning of period $ (145 ) $ 1,722 $ 625 $ 1,694 Capital contributions by noncontrolling interest — 231 — 531 Sales of noncontrolling interests — — — 679 Accretion to redemption value of noncontrolling interests 481 — 481 — Reclassification of noncontrolling interest subject to put provision (744 ) — (744 ) — Net loss attributable to noncontrolling interest in consolidated subsidiary (376 ) (672 ) (1,146 ) (1,623 ) Balance at end of period $ (784 ) $ 1,281 $ (784 ) $ 1,281

Derivative Instruments and Hedg

Derivative Instruments and Hedging	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging	Derivative Instruments and Hedging We operate manufacturing and service facilities in Mexico, Germany, and Italy, and we purchase materials and pay our employees at those facilities in pesos and euros, and as such, we are potentially exposed to adverse as well as beneficial movements in currency exchange rates. We enter into foreign exchange forward contracts to minimize the impact of currency exchange rate fluctuations on these peso and euro denominated expenses. These contracts have durations of up to twelve months and are designated as cash flow hedges. The counterparties to these foreign exchange forward contracts are creditworthy financial institutions; therefore, we do not consider the risk of counterparty nonperformance to be material. As of September 30, 2017 and December 31, 2016 , the notional amount of our outstanding contracts that are designated as cash flow hedges was $22.4 million and $18.6 million , respectively. The fair value of these contracts is recorded on the balance sheet within prepaid expenses and other current assets or accrued expenses depending on the gain (loss) position. The fair value of these contracts was a net asset of $1.9 million at September 30, 2017 and a net liability of $1.8 million at December 31, 2016 , respectively. The cash flows related to our currency exchange contracts are classified as operating cash flows, which is consistent with the cash flow treatment of the underlying items being hedged. Gains or losses related to hedge ineffectiveness recognized in earnings were not material during the nine months ended September 30, 2017 and 2016 . Given the short-term nature of our contracts, any gains or losses recorded within accumulated other comprehensive income (loss) will be recognized in earnings within the next twelve months. The following table presents the effect of these contracts designated as cash flow hedges on our condensed consolidated financial statements (in thousands): Gain (Loss) Recognized in OCI (Effective Portion) Gain (Loss) Reclassified from OCI into Income (Effective Portion) Classification within the Condensed Consolidated Statement of Comprehensive Loss Three Months Ended September 30, 2017 Foreign exchange forward contracts $ 116 $ 733 Cost of revenues Nine Months Ended September 30, 2017 Foreign exchange forward contracts $ 4,211 $ 254 Cost of revenues Three Months Ended September 30, 2016 Foreign exchange forward contracts $ (386 ) $ (381 ) Cost of revenues Nine Months Ended September 30, 2016 Foreign exchange forward contracts $ (1,338 ) $ (1,430 ) Cost of revenues

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income The following additional information is provided with respect to the accumulated other comprehensive (loss) income as presented on the condensed consolidated balance sheets (in thousands): Unrealized gain on derivative instruments Other (2) Total Balance, net of tax, as of December 31, 2016 $ (2,285 ) $ (3,816 ) $ (6,101 ) Other comprehensive income before reclassifications, net of $1,581 tax during 2017 2,630 1,830 4,460 Gain reclassified to earnings (1) (254 ) — (254 ) Total other comprehensive income, net of tax 2,376 1,830 4,206 Balance, net of tax, as of September 30, 2017 $ 91 $ (1,986 ) $ (1,895 ) (1) Reclassifications of gains/ losses on derivative instruments are included in cost of revenues on the condensed consolidated statement of comprehensive loss. See Note 15 , Derivative Instruments and Hedging for further information. (2) Other includes cumulative translation adjustments and, to a lesser extent, pension benefits.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We have certain financial assets and liabilities measured at fair value on a recurring and non-recurring basis recorded in our condensed consolidated balance sheets. The fair value measurements used are based on quoted prices, when available, or through the use of alternative approaches. The inputs used to determine fair value have been classified as Level 1, 2 or 3. Fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Fair values determined by Level 2 inputs utilize data points that are observable such as quoted prices, interest rates and yield curves for similar instruments and model-derived valuations whose inputs are observable. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability. We measure the fair value of our foreign exchange forward contracts classified as derivative instruments using an income approach, based on prevailing market forward rates less the contract rate multiplied by the notional amount. The product of this calculation is then adjusted for counterparty risk. We did not have any transfers between Level 1 and Level 2 and Level 3 during the nine months ended September 30, 2017 . The following tables present assets and liabilities measured at fair value on a recurring basis and their level within the value hierarchy (in thousands): September 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets Money market funds (1) $ 34,945 $ — $ — $ 34,945 Foreign exchange forward contracts (2) — 2,096 — 2,096 Liabilities Foreign exchange forward contracts (2) $ — $ 203 $ — $ 203 December 31, 2016 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Fair Value Assets Money market funds (1) $ 34,804 $ — $ — $ 34,804 Liabilities Foreign exchange forward contracts (2) $ — $ 1,771 $ — $ 1,771 (1) Money market funds are included within cash and cash equivalents. (2) Foreign exchange forward contracts are included within prepaid expenses and other current assets or accrued expenses depending on the gain (loss) position. The carrying amount of our long-term debt approximates fair value at September 30, 2017 and December 31, 2016 . The fair value of our long-term debt was estimated using inputs derived principally from market observable data, including current rates offered to us for debt of the same or similar remaining maturities. Within the hierarchy of fair value measurements, these are Level 2 inputs. The carrying amounts reflected in the condensed consolidated balance sheets for cash and cash equivalents (including money market funds), accounts receivable, prepaid expenses and other current and non-current assets, accounts payable and accrued expenses approximate fair value due to their short-term nature. In September 2017, we acquired a 2.5% equity ownership of a privately held dialysis services company in exchange for $2.5 million in cash. This investment is accounted for using the cost method as we are unable to exercise any significant influence over the company. The investment has been recorded at historical cost, classified within other assets on our condensed consolidated balance sheet, and is reviewed for events or changes in circumstances that may have a significant adverse effect on the fair value of the investment. There have been no changes in circumstances or identified events that may have a significant adverse effect on the fair value.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information The following additional information is provided with respect to the condensed consolidated statements of cash flows (in thousands): Nine Months Ended September 30, 2017 2016 Noncash Investing and Financing Activities: Transfers from inventory to field equipment $ 13,709 $ 14,629 Transfers from field equipment to deferred cost of revenues 7,570 10,396 Market value of shares received in payment for exercise of stock options 2,771 1,963 Redemption of noncontrolling interest 481 — PP&E financed by construction liability 109 187 Property and equipment acquired under capital lease — 127

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements as of September 30, 2017 and December 31, 2016 and for the three and nine months ended September 30, 2017 and 2016 , and related notes, are unaudited but, in the opinion of our management, include all adjustments, consisting of normal recurring adjustments, that are necessary for fair statement of the interim periods presented. Our unaudited condensed consolidated financial statements have been prepared following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under these rules, we have condensed or omitted certain footnotes and other financial information that are normally required by U.S. generally accepted accounting principles (GAAP). Our accounting policies are described in the notes to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2016 ( 2016 Annual Report) and updated, as necessary, in this Quarterly Report on Form 10-Q (Quarterly Report). Operating results for any interim period are not necessarily indicative of results for the entire year or future periods. The December 31, 2016 condensed consolidated balance sheet contained herein was derived from audited financial statements, but does not include all disclosures that would be required for audited financial statements under GAAP. For further information, refer to the consolidated financial statements and footnotes thereto included in our 2016 Annual Report.
Use of Estimates	The preparation of our condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Such financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments are of a normal recurring nature.
Principles of Consolidation	Principles of Consolidation Our condensed consolidated financial statements include the accounts of NxStage Medical, Inc. and our wholly-owned subsidiaries and other entities in which we maintain a majority voting interests or for which we maintain effective control, including variable interest entities ("VIEs") for which we are deemed the primary beneficiary. All significant intercompany balances and transactions have been eliminated. Noncontrolling interests represent the proportionate equity interests in the consolidated entities that are not wholly owned by us. Noncontrolling interests of acquired entities are recognized at their initial fair value.
Concentration of Credit Risk	Concentration of Credit Risk Concentration of credit risk with respect to accounts receivable is primarily limited to certain customers to whom we make substantial sales.
Warranty Costs	Warranty Costs We accrue estimated costs that we may incur under our product warranty programs at the time the product revenue is recognized, based on contractual rights and historical experience. Warranty expense is included in cost of revenues in the condensed consolidated statements of comprehensive loss.
Intangibles and Other Long-Lived Assets	Intangibles and Other Long-Lived Assets Intangible assets are carried at cost less accumulated amortization. For assets with determinable useful lives, amortization is recognized using the straight-line method over the estimated economic lives of the respective intangible assets. Long-lived assets, including intangible assets, are evaluated for recoverability whenever events or circumstances indicate that their carrying value may not be recoverable. Recoverability of long-lived assets is assessed at the lowest level for which discrete cash flows are available and is measured by comparing the asset group’s carrying value to its expected non-discounted future cash flows. If the sum of the expected non-discounted future cash flows is less than the carrying amount of the long-lived assets, an impairment loss is recognized for excess of the carrying amount of the asset group over its fair value. In 2017, events and circumstances have indicated that certain long-lived tangible assets in the Services segment may not be recoverable. Therefore, a recoverability test was performed at the center level by comparing the carrying value of each center to its estimated future undiscounted cash flows, within the initial lease term (which is the equivalent to the depreciable life of the centers' most significant asset, its leasehold improvements). As of September 30, 2017, our expected non-discounted future cash flows for the majority of our centers indicated such carrying amounts were expected to be recovered. No impairment charge was recognized during the third quarter of 2017. We recorded an impairment charge during the second quarter of 2017 of $0.3 million in cost of revenue to write-down certain center level assets within our Services segment. Our expected non-discounted future cash flows used in our impairment testing are based upon cash flow projections and, if appropriate, include assumed proceeds upon sale of the asset group at the end of the cash flow period. We believe our procedures for developing cash flow projections, including the estimated sales proceeds, are reasonable and consistent with current market conditions for each of the dates when impairment testing has been performed. Developing cash flow projections requires significant estimates and judgment. Among other things, slower than expected patient ramp or lower than expected reimbursement rates would negatively impact our cash flow projections in the near term. We had $15.0 million of long-lived assets at our Services segment at September 30, 2017. It is reasonably possible that our cash flow projections may change in the near term resulting in the need to record an impairment charge for at least some portion of these assets.
Goodwill	Goodwill We test goodwill for impairment during the fourth quarter, or more frequently when events or changes in circumstances indicate that the goodwill might be impaired. This test includes first a qualitative assessment and then, if necessary, a quantitative assessment to determine if the fair value of a reporting unit is less than its carrying amount. Our System One, In-center and Services reporting units contain goodwill of $41.1 million , $0.5 million and $1.1 million , respectively. Factors considered in the qualitative assessment include, but are not limited to, both macroeconomic conditions and entity-specific conditions. For the quantitative assessment the reporting unit's fair value is estimated using a discounted cash flow or other fair value measurement. During 2016 and 2015 we utilized the qualitative assessment to assess the fair value of our System One and In-center reporting units and concluded that it was more likely than not that the fair value of our reporting units was greater than their carrying value. During 2016, for our Services reporting unit, we utilized the quantitative assessment noting that the fair value of the reporting unit exceeds its carrying value, indicating that goodwill was not impaired. We estimated the fair value of our Services reporting unit using a discounted cash flow approach. There have been no events or changes in circumstances since the date of our last goodwill impairment tests that would indicate it is more likely than not that the fair value of our reporting units is less than their carry value. Our Services reporting unit, with a goodwill of $1.1 million at September 30, 2017 , has been identified as having a higher risk for impairment. Future events that could have a negative impact on the levels of excess fair value over carrying value of our Services reporting unit include, but are not limited to, changes in discount rates, slower than expected patient ramp, lower than expected reimbursement rates or operating income, increases in capital expenditures or unfavorable changes in working capital. Negative changes in one or more of these factors, among others, could results in a goodwill impairment charge of up to $1.1 million in the future.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Implemented Accounting Pronouncements In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): "Simplifying the Measurement of Inventory." The update requires that an entity should measure in scope inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments were effective for us beginning January 1, 2017. The adoption of this update did not have a material impact on our financial statements. In March 2016, the FASB issued ASU No. 2016-09: “Improvements to Employee Share-Based Payment Accounting,” which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The new guidance was effective for us beginning January 1, 2017. We have elected to continue to estimate forfeiture rates. This new standard impacts our income tax footnote disclosures. We have tax effected federal net operating losses of $18.0 million and state net operating losses of $1.6 million that are attributable to excess tax deductions related to stock-based compensation from prior years. Upon adoption the cumulative excess tax deductions related to stock-based compensation that were previously unrecognized are being recognized as a deferred tax asset and are fully offset by a valuation allowance. Other than this change in our income tax footnote disclosures, the adoption does not have a material impact on our financial statements. In January 2017, the FASB issued ASU No. 2017-04: "Intangibles - Goodwill and Other Topics (Topic 350): Simplifying the Test for Goodwill Impairment". The purpose of this update is to reduce the cost and complexity of evaluating goodwill for impairment. It eliminates the need for entities to calculate the impaired fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. Under this update, an entity will perform its goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge is recognized for the amount by which the carrying value exceeds the reporting unit's fair value. We elected to early adopt this update on a prospective basis for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this update did not have a material impact on our financial statements. In May 2017, the FASB issued ASU No. 2017-09: "Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting". The purpose of this update is to reduce the diversity in practice and result in fewer changes to the terms of an award being accounted for as modifications. It will allow companies to make non-substantive changes to their share-based payment awards, without accounting for them as modifications. It does not change the accounting for modifications. Under this update, an entity will apply the modification accounting guidance only if the value (or calculated value or intrinsic value, if those measurement methods are used), vesting conditions or classification of the award as an equity or liability instrument changes. This update also clarifies that a modification to an award could be significant and therefore require disclosure, even if modification accounting is not required. The new guidance will be applied prospectively to awards modified on or after the adoption date. We elected to early adopt this update in the second quarter of 2017. The adoption of this update did not have a material impact on our financial statements. Recent Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-9: “Revenue from Contracts with Customers.” The standard provides that revenue should be recognized when an entity transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenues and cash flow arising from contracts with customers. The FASB has issued several amendments and updates to the new revenue standard, including how an entity should identify performance obligations. As amended, the new guidance is effective for us beginning January 1, 2018. The new guidance allows for full retrospective adoption applied to all periods presented or a modified retrospective adoption with the cumulative effect of initially applying the new guidance recognized at the date of initial application. In 2016, we commenced our evaluation of the impact of the standard, by establishing a cross functional team and evaluating the anticipated impact on significant contracts from each of our business segments. We intend to use the modified retrospective adoption methodology. We are evaluating the potential impact of the standard on the related disclosures and are comparing our current policies and practices to the requirements of the standard. We have developed a project plan to develop processes and tools and to assess the internal control structure in order to adopt the standard on January 1, 2018. We believe that the standard will impact the timing of revenue recognition for our Services segment as the standard eliminates cash basis revenue recognition and instead requires revenues to be estimated and recognized upon transfer of the promised goods and services. The adoption of the standard is not expected to have a material impact on our other segments. We have periodically briefed our Audit Committee on our progress made towards adoption. Based on our evaluation to date, we anticipate being able to estimate the quantitative impacts of adopting the ASU in connection with the filing of our 2017 Form 10-K. In February 2016, the FASB issued ASU No. 2016-02: "Accounting for Leases" which amends the existing accounting standards for leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than twelve months. For lessees, leases will continue to be classified as either operating or financing in the income statement. This ASU is required to be applied with a modified retrospective approach and requires application of the new standard at the beginning of the earliest comparative period presented. The new guidance is effective for us beginning January 1, 2019 and early adoption is permitted. We intend to adopt this standard as of January 1, 2019. We are currently evaluating the potential impact this standard will have on our financial statements. In January 2017, the FASB issued ASU No. 2017-01: "Business Combinations (Topic 805): Clarifying the Definition of a Business" which changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. The update is effective for us beginning January 1, 2018. Early adoption is permitted, including for interim or annual periods in which the financial statements have not been issued or made available for issuance. The adoption of this update is not expected to have a material impact on our financial statements.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed by dividing loss attributable to NxStage Medical, Inc. common stockholders (the numerator) by the weighted-average number of common shares outstanding (the denominator) for the period. The computation of diluted loss per share is similar to basic loss per share, except that the denominator is increased to include the number of additional common shares that would have been outstanding if the potentially dilutive common shares had been issued.
Segment Disclosure	We have three reportable business segments: System One, In-Center, and Services. The operating results of NxStage Kidney Care are included in our Services segment. We refer to our System One segment, In-Center segment, and Other category as our products business. Our System One segment includes revenues from sales of the System One and PureFlow SL dialysate preparation equipment and sales of disposable products to customers in the home market, including through our NxStage Kidney Care dialysis centers, and critical care market. The home market is devoted to the treatment of ESRD patients in the home or a home-like setting, including skilled nursing facilities, while the critical care market is devoted to the treatment of hospital-based patients with acute kidney failure or fluid overload. Some of our largest customers in the home market provide outsourced renal dialysis services to some of our customers in the critical care market. Sales of product to both markets are made primarily through dedicated sales forces and distributed directly to the customer, or the patient, with certain products sold through distributors. Our In-Center segment includes revenues from the sale of blood tubing sets and needles for hemodialysis primarily for the treatment of ESRD patients at dialysis centers and needles for apheresis. Nearly all In-Center products are sold through national distributors. The remainder of our products business, which is included within the Other category, relates to the manufacturing of dialyzers for sale to Asahi Kasei Kuraray Medical Co., Ltd. (Asahi) and research and development and general and administrative expenses that are excluded from the segment operating performance measures. Our Services segment includes revenues from dialysis services provided to patients at our NxStage Kidney Care dialysis centers. Sales of the System One and related products to our NxStage Kidney Care dialysis centers are included in System One segment revenues, which are then eliminated upon consolidation. The accounting policies of our reportable segments are described in Note 2 to the consolidated financial statements included in our 2016 Annual Report and updated, as necessary, in Note 2 to the condensed consolidated financial statements included in this Quarterly Report. Our chief operating decision maker allocates resources to our business segments and assesses segment performance based on segment profit (loss), which consists of revenues less cost of revenues, selling and marketing and distribution expenses.
Fair Value Measurements	Fair Value Measurements We have certain financial assets and liabilities measured at fair value on a recurring and non-recurring basis recorded in our condensed consolidated balance sheets. The fair value measurements used are based on quoted prices, when available, or through the use of alternative approaches. The inputs used to determine fair value have been classified as Level 1, 2 or 3. Fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Fair values determined by Level 2 inputs utilize data points that are observable such as quoted prices, interest rates and yield curves for similar instruments and model-derived valuations whose inputs are observable. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability. We measure the fair value of our foreign exchange forward contracts classified as derivative instruments using an income approach, based on prevailing market forward rates less the contract rate multiplied by the notional amount. The product of this calculation is then adjusted for counterparty risk.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Schedule of Rollforward of Warranty Accrual	The following is a rollforward of our warranty accrual (in thousands): Balance at December 31, 2016 $ 280 Provision 317 Usage (328 ) Balance at September 30, 2017 $ 269

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2017
Inventory Disclosure [Abstract]
Components of Inventory	The components of inventory are as follows (in thousands): September 30, December 31, Purchased components $ 14,861 $ 14,967 Work in process 14,891 13,939 Finished goods 20,916 17,939 Total $ 50,668 $ 46,845

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of Anti-dilutive Net Loss Per Share	The following potential common stock equivalents, as calculated using the treasury stock method, were not included in the computation of diluted net loss per share as their effect would have been anti-dilutive due to the net loss incurred (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Options to purchase common stock 1,069 1,096 1,126 682 Unvested restricted stock 327 382 238 359 Total 1,396 1,478 1,364 1,041

Accrued Expenses, Other Curre28

Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities (Tables)	9 Months Ended
	Sep. 30, 2017
Payables and Accruals [Abstract]
Components of Accrued Expenses	The components of accrued expenses are as follows (in thousands): September 30, December 31, Payroll, compensation and related benefits $ 12,637 $ 14,086 Distribution expenses 5,132 4,804 General and administrative expenses 1,830 4,415 Audit, legal and consulting fees 3,469 1,373 Other manufacturing costs 1,481 1,891 Other 4,076 4,416 Total $ 28,625 $ 30,985
Components of Other Current liabilities	The components of other current liabilities are as follows (in thousands): September 30, December 31, Capital lease obligations $ 2,154 $ 1,840 Deferred revenue, current portion 1,526 1,035 Other 922 895 Total $ 4,602 $ 3,770
Components of Other Long-term Liabilities	The components of other long-term liabilities are as follows (in thousands): September 30, December 31, Capital lease obligations $ 11,595 $ 9,991 Lease incentive obligations 2,842 3,059 Benefit plan obligations 2,020 1,678 Other 1,537 840 Total $ 17,994 $ 15,568

Segment Disclosures (Tables)

Segment Disclosures (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Summary of Operating Performance of Reportable Segments	The following summarizes the operating performance of our reportable segments (in thousands): System One In-Center Other Services Intersegment Elimination Total Three Months Ended September 30, 2017 Revenues from external customers $ 73,479 $ 15,465 $ 3,392 $ 4,959 $ — $ 97,295 Intersegment revenues 1,197 — — — (1,197 ) — Revenues 74,676 15,465 3,392 4,959 (1,197 ) 97,295 Segment profit (loss) 18,799 2,131 (23,602 ) (5,626 ) 15 (8,283 ) Depreciation and amortization 5,539 564 1,088 1,318 (26 ) 8,483 Three Months Ended September 30, 2016 Revenues from external customers $ 70,011 $ 14,493 $ 3,601 $ 3,846 $ — $ 91,951 Intersegment revenues 1,930 — — — (1,930 ) — Revenues 71,941 14,493 $ 3,601 3,846 (1,930 ) 91,951 Segment profit (loss) 19,828 2,463 (15,676 ) (6,384 ) (207 ) 24 Depreciation and amortization 6,015 500 1,134 1,232 (556 ) 8,325 Nine Months Ended September 30, 2017 Revenues from external customers $ 220,950 $ 45,397 $ 9,127 $ 14,866 $ — $ 290,340 Intersegment revenues 3,845 — — — (3,845 ) — Revenues 224,795 45,397 9,127 14,866 (3,845 ) 290,340 Segment profit (loss) 60,021 6,152 (60,445 ) (17,724 ) (24 ) (12,020 ) Depreciation and amortization 16,601 1,633 3,252 3,888 (53 ) 25,321 Nine Months Ended September 30, 2016 Revenues from external customers $ 205,538 $ 47,990 $ 9,190 $ 10,647 $ — $ 273,365 Intersegment revenues 5,553 — — — (5,553 ) — Revenues 211,091 47,990 $ 9,190 10,647 (5,553 ) 273,365 Segment profit (loss) 55,997 8,155 (46,332 ) (19,354 ) (597 ) (2,131 ) Depreciation and amortization 17,362 1,489 3,361 3,441 (1,679 ) 23,974
Summary of Customers Who Individually Make Up Greater than 10% of Total Revenues	The following table summarizes the number of customers who individually make up greater than ten percent of total revenues: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 DaVita 20 % 21 % 20 % 20 % Fresenius 20 % 18 % 19 % 18 %

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-Based Compensation Expense in Consolidated Statements of Comprehensive Loss	The following table presents stock-based compensation expense included in our condensed consolidated statements of comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Cost of revenues $ 335 $ 314 $ 902 $ 1,056 Selling and marketing 1,054 781 3,047 2,562 Research and development 437 344 1,154 1,148 General and administrative 1,534 855 3,581 2,922 Total $ 3,360 $ 2,294 $ 8,684 $ 7,688

Noncontrolling Interest (Tables

Noncontrolling Interest (Tables)	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Schedule of Changes in Noncontrolling Interest	The following table sets forth the changes in noncontrolling interest not subject to put provisions for the three and nine months ended September 30, 2017 and 2016 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Balance at beginning of period $ (145 ) $ 1,722 $ 625 $ 1,694 Capital contributions by noncontrolling interest — 231 — 531 Sales of noncontrolling interests — — — 679 Accretion to redemption value of noncontrolling interests 481 — 481 — Reclassification of noncontrolling interest subject to put provision (744 ) — (744 ) — Net loss attributable to noncontrolling interest in consolidated subsidiary (376 ) (672 ) (1,146 ) (1,623 ) Balance at end of period $ (784 ) $ 1,281 $ (784 ) $ 1,281

Derivative Instruments and He32

Derivative Instruments and Hedging (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effect of Contracts Designated as Cash Flow Hedges on Consolidated Financial Statements	The following table presents the effect of these contracts designated as cash flow hedges on our condensed consolidated financial statements (in thousands): Gain (Loss) Recognized in OCI (Effective Portion) Gain (Loss) Reclassified from OCI into Income (Effective Portion) Classification within the Condensed Consolidated Statement of Comprehensive Loss Three Months Ended September 30, 2017 Foreign exchange forward contracts $ 116 $ 733 Cost of revenues Nine Months Ended September 30, 2017 Foreign exchange forward contracts $ 4,211 $ 254 Cost of revenues Three Months Ended September 30, 2016 Foreign exchange forward contracts $ (386 ) $ (381 ) Cost of revenues Nine Months Ended September 30, 2016 Foreign exchange forward contracts $ (1,338 ) $ (1,430 ) Cost of revenues

Accumulated Other Comprehensi33

Accumulated Other Comprehensive (Loss) Income (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Summary of Additional Information on Accumulated Other Comprehensive (Loss) Income	The following additional information is provided with respect to the accumulated other comprehensive (loss) income as presented on the condensed consolidated balance sheets (in thousands): Unrealized gain on derivative instruments Other (2) Total Balance, net of tax, as of December 31, 2016 $ (2,285 ) $ (3,816 ) $ (6,101 ) Other comprehensive income before reclassifications, net of $1,581 tax during 2017 2,630 1,830 4,460 Gain reclassified to earnings (1) (254 ) — (254 ) Total other comprehensive income, net of tax 2,376 1,830 4,206 Balance, net of tax, as of September 30, 2017 $ 91 $ (1,986 ) $ (1,895 ) (1) Reclassifications of gains/ losses on derivative instruments are included in cost of revenues on the condensed consolidated statement of comprehensive loss. See Note 15 , Derivative Instruments and Hedging for further information. (2) Other includes cumulative translation adjustments and, to a lesser extent, pension benefits.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present assets and liabilities measured at fair value on a recurring basis and their level within the value hierarchy (in thousands): September 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets Money market funds (1) $ 34,945 $ — $ — $ 34,945 Foreign exchange forward contracts (2) — 2,096 — 2,096 Liabilities Foreign exchange forward contracts (2) $ — $ 203 $ — $ 203 December 31, 2016 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total Fair Value Assets Money market funds (1) $ 34,804 $ — $ — $ 34,804 Liabilities Foreign exchange forward contracts (2) $ — $ 1,771 $ — $ 1,771 (1) Money market funds are included within cash and cash equivalents. (2) Foreign exchange forward contracts are included within prepaid expenses and other current assets or accrued expenses depending on the gain (loss) position.

Supplemental Cash Flow Inform35

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Summary of Supplemental Cash Flow Information	The following additional information is provided with respect to the condensed consolidated statements of cash flows (in thousands): Nine Months Ended September 30, 2017 2016 Noncash Investing and Financing Activities: Transfers from inventory to field equipment $ 13,709 $ 14,629 Transfers from field equipment to deferred cost of revenues 7,570 10,396 Market value of shares received in payment for exercise of stock options 2,771 1,963 Redemption of noncontrolling interest 481 — PP&E financed by construction liability 109 187 Property and equipment acquired under capital lease — 127

Nature of Operations, Propose36

Nature of Operations, Proposed Merger, Basis of Presentation and Principles of Consolidation (Details) $ / shares in Units, $ in Millions	Oct. 27, 2017USD ($)$ / shares	Sep. 30, 2017country
Accounting Policies [Abstract]
Number of countries in which entity operates | country		21
Subsequent Event | Fresenius Medical Care Holdings, Inc.
Business Acquisition [Line Items]
Share price (in dollars per share) | $ / shares	$ 30
Termination of merger agreement, extension term	180 days
Termination of merger agreement, fee paid to acquiree	$ 100
Termination of merger agreement, fee paid to acquirer	$ 60
Termination of merger agreement, period to publicly withdraw from the agreement before termination	10 days
Termination of merger agreement, period to not enter into alternative acquisition after termination	12 months

Summary of Significant Accoun37

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)customer
Accounting Policies [Line Items]
Asset impairment recognized	$ 0
Goodwill	42,748,000		$ 42,648,000
Federal
Accounting Policies [Line Items]
Operating loss carryforwards			18,000,000
State
Accounting Policies [Line Items]
Operating loss carryforwards			$ 1,600,000
System One
Accounting Policies [Line Items]
Goodwill	41,100,000
In-Center
Accounting Policies [Line Items]
Goodwill	500,000
Services
Accounting Policies [Line Items]
Asset impairment recognized		$ 300,000
Long-lived assets	15,000,000
Goodwill	$ 1,100,000
Customer Concentration Risk | Accounts Receivable
Accounting Policies [Line Items]
Number of customers with accounts receivable balances | customer			2
Customer Concentration Risk | Accounts Receivable | Customer Two
Accounting Policies [Line Items]
Percentage of accounts receivable			12.00%
Customer Concentration Risk | Accounts Receivable | Customer Three
Accounting Policies [Line Items]
Percentage of accounts receivable			10.00%

Summary of Significant Accoun38

Summary of Significant Accounting Policies - Schedule of Rollforward of Warranty Accrual (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of period	$ 280
Provision	317
Usage	(328)
Balance at end of period	$ 269

Inventory - Components of Inven

Inventory - Components of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Purchased components	$ 14,861	$ 14,967
Work in process	14,891	13,939
Finished goods	20,916	17,939
Total	$ 50,668	$ 46,845

Property and Equipment, and Fie

Property and Equipment, and Field Equipment - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Property And Equipment Excluding Field Equipment
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 57.3	$ 47.2
Field Equipment
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 52.5	$ 48.4

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Accumulated amortization of intangible assets	$ 26.5	$ 25

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Anti-dilutive Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from computation of earnings per share (in shares)	1,396	1,478	1,364	1,041
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from computation of earnings per share (in shares)	1,069	1,096	1,126	682
Unvested restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from computation of earnings per share (in shares)	327	382	238	359

Accrued Expenses, Other Curre43

Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Payroll, compensation and related benefits	$ 12,637	$ 14,086
Distribution expenses	5,132	4,804
General and administrative expenses	1,830	4,415
Audit, legal and consulting fees	3,469	1,373
Other manufacturing costs	1,481	1,891
Other	4,076	4,416
Total	$ 28,625	$ 30,985

Accrued Expenses, Other Curre44

Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities - Components of Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Capital lease obligations	$ 2,154	$ 1,840
Deferred revenue, current portion	1,526	1,035
Other	922	895
Total	$ 4,602	$ 3,770

Accrued Expenses, Other Curre45

Accrued Expenses, Other Current Liabilities and Other Long-Term Liabilities - Components of Other Long-term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Capital lease obligations	$ 11,595	$ 9,991
Lease incentive obligations	2,842	3,059
Benefit plan obligations	2,020	1,678
Other	1,537	840
Total	$ 17,994	$ 15,568

Debt and Capital Lease Obliga46

Debt and Capital Lease Obligations (Details) $ in Millions	1 Months Ended
	May 31, 2017USD ($)
Debt Instrument [Line Items]
Extinguishment of small loan	$ 0.9
Capital Lease Obligations
Debt Instrument [Line Items]
Capital lease obligation term	5 years

Segment Disclosures - Additiona

Segment Disclosures - Additional Information (Details)	9 Months Ended
	Sep. 30, 2017segment
Segment Reporting [Abstract]
Number of reporting segments	3

Segment Disclosures - Summary o

Segment Disclosures - Summary of Operating Performance of Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 97,295	$ 91,951	$ 290,340	$ 273,365
Segment profit (loss)	(8,283)	24	(12,020)	(2,131)
Depreciation and amortization	8,483	8,325	25,321	23,974
System One
Segment Reporting Information [Line Items]
Revenues	73,479	70,011	220,950	205,538
In-Center
Segment Reporting Information [Line Items]
Revenues	15,465	14,493	45,397	47,990
Services
Segment Reporting Information [Line Items]
Revenues	4,959	3,846	14,866	10,647
Operating Segments | System One
Segment Reporting Information [Line Items]
Revenues	74,676	71,941	224,795	211,091
Segment profit (loss)	18,799	19,828	60,021	55,997
Depreciation and amortization	5,539	6,015	16,601	17,362
Operating Segments | In-Center
Segment Reporting Information [Line Items]
Revenues	15,465	14,493	45,397	47,990
Segment profit (loss)	2,131	2,463	6,152	8,155
Depreciation and amortization	564	500	1,633	1,489
Operating Segments | Services
Segment Reporting Information [Line Items]
Revenues	4,959	3,846	14,866	10,647
Segment profit (loss)	(5,626)	(6,384)	(17,724)	(19,354)
Depreciation and amortization	1,318	1,232	3,888	3,441
Other
Segment Reporting Information [Line Items]
Revenues	3,392	3,601	9,127	9,190
Segment profit (loss)	(23,602)	(15,676)	(60,445)	(46,332)
Depreciation and amortization	1,088	1,134	3,252	3,361
Intersegment Elimination
Segment Reporting Information [Line Items]
Revenues	(1,197)	(1,930)	(3,845)	(5,553)
Segment profit (loss)	15	(207)	(24)	(597)
Depreciation and amortization	(26)	(556)	(53)	(1,679)
Intersegment Elimination | System One
Segment Reporting Information [Line Items]
Revenues	$ 1,197	$ 1,930	$ 3,845	$ 5,553

Segment Disclosures - Summary49

Segment Disclosures - Summary of Customers Who Individually Make Up Greater than 10% of Total Revenues (Details) - Sales Revenue, Net - Customer Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
DaVita
Revenue, Major Customer [Line Items]
Percentage of revenues	20.00%	21.00%	20.00%	20.00%
Fresenius
Revenue, Major Customer [Line Items]
Percentage of revenues	20.00%	18.00%	19.00%	18.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Allocation adjustments, amount	$ 100		$ (1,100)
Benefit from income taxes	(469)	$ (324)	166	$ (1,007)
Liability for unrecognized tax benefits	800		800
Interest and penalties accrued	100		100
Interest and penalties accrued during period	$ 0		$ 0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense in Consolidated Statements of Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,360	$ 2,294	$ 8,684	$ 7,688
Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	335	314	902	1,056
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,054	781	3,047	2,562
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	437	344	1,154	1,148
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,534	$ 855	$ 3,581	$ 2,922

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - $ / shares	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period (in shares)			7,480	20,351	675,358	1,334,351
Weighted-average fair value of options granted (in dollars per share)					$ 9.92	$ 5.89
Options to purchase common stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Options to purchase common stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					4 years
Unvested restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period (in shares)		231,384	20,970	23,380	175,895	219,846
Weighted-average fair value of restricted stock granted (in dollars per share)	$ 23.14				$ 27.23	$ 17.34
Restricted stock vests over a requisite service period	3 years
Unvested restricted stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					3 years
Unvested restricted stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					4 years

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Shares delivered or surrendered in payment for the exercise of stock options (in shares)	97,828	100,571

Noncontrolling Interest - Addit

Noncontrolling Interest - Additional Information (Details) $ in Thousands	Sep. 30, 2017USD ($)entity	Dec. 31, 2016USD ($)
Noncontrolling Interest [Abstract]
Number of VIEs | entity	5
Total assets of variable interest entities	$ 5,800	$ 8,000
Total liabilities and noncontrolling interest of variable interest entities	5,900	7,200
Noncontrolling interests subject to put provisions	$ 650	$ 50

Noncontrolling Interest - Sched

Noncontrolling Interest - Schedule of Changes in Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ (145)	$ 1,722	$ 625	$ 1,694
Capital contributions by noncontrolling interest	0	231	0	531
Sales of noncontrolling interests	0	0	0	679
Accretion to redemption value of noncontrolling interests	481	0	481	0
Reclassification of noncontrolling interest subject to put provision	(744)	0	(744)	0
Net loss attributable to noncontrolling interest in consolidated subsidiary	(376)	(672)	(1,146)	(1,623)
Balance at end of period	$ (784)	$ 1,281	$ (784)	$ 1,281

Derivative Instruments and He56

Derivative Instruments and Hedging - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Hedging Transactions And Derivative Financial Instruments [Line Items]
Period of cash flow hedges (up to)	12 months
Gain (loss) on ineffectiveness in earnings	$ 0	$ 0
Foreign exchange forward contracts | Cash Flow Hedges
Hedging Transactions And Derivative Financial Instruments [Line Items]
Notional amount of outstanding contracts	22.4		$ 18.6
Fair value of outstanding contracts assets	$ 1.9
Fair value of outstanding contracts liability			$ 1.8

Derivative Instruments and He57

Derivative Instruments and Hedging - Effect of Contracts Designated as Cash Flow Hedges on Consolidated Financial Statements (Details) - Foreign exchange forward contracts - Cost of revenues - Cash Flow Hedges - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI (Effective Portion)	$ 116	$ (386)	$ 4,211	$ (1,338)
Gain (Loss) Reclassified from OCI into Income (Effective Portion)	$ 733	$ (381)	$ 254	$ (1,430)

Accumulated Other Comprehensi58

Accumulated Other Comprehensive (Loss) Income - Summary of Additional Information on Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (1,895)		$ (1,895)		$ (6,101)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance, net of tax			202,023
Total other comprehensive (loss) income	(393)	$ (78)	4,206	$ (297)
Ending balance, net of tax	212,540		212,540
U.S. tax expense allocated to OCI			1,581
Unrealized gain on derivative instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance, net of tax			(2,285)
Other comprehensive income before reclassifications, net of $1,581 tax during 2017			2,630
Gain reclassified to earnings			(254)
Total other comprehensive (loss) income			2,376
Ending balance, net of tax	91		91
Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance, net of tax			(3,816)
Other comprehensive income before reclassifications, net of $1,581 tax during 2017			1,830
Gain reclassified to earnings			0
Total other comprehensive (loss) income			1,830
Ending balance, net of tax	(1,986)		(1,986)
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance, net of tax			(6,101)
Other comprehensive income before reclassifications, net of $1,581 tax during 2017			4,460
Gain reclassified to earnings			(254)
Total other comprehensive (loss) income			4,206
Ending balance, net of tax	$ (1,895)		$ (1,895)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements, Recurring Basis - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	$ 2,096
Liabilities
Foreign exchange forward contracts	203	$ 1,771
Money market funds
Assets
Money market funds	34,945	34,804
Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	0
Liabilities
Foreign exchange forward contracts	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets
Money market funds	34,945	34,804
Significant Other Observable Inputs (Level 2) | Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	2,096
Liabilities
Foreign exchange forward contracts	203	1,771
Significant Other Observable Inputs (Level 2) | Money market funds
Assets
Money market funds	0	0
Significant Unobservable Inputs (Level 3) | Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	0
Liabilities
Foreign exchange forward contracts	0	0
Significant Unobservable Inputs (Level 3) | Money market funds
Assets
Money market funds	$ 0	$ 0

Fair Value Measurements Additio

Fair Value Measurements Additional Details (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Ownership percentage	2.50%	2.50%
Payments to Acquire Investments	$ 2,500	$ 2,500	$ 0

Supplemental Cash Flow Inform61

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Noncash Investing and Financing Activities:
Transfers from inventory to field equipment			$ 13,709	$ 14,629
Transfers from field equipment to deferred cost of revenues			7,570	10,396
Market value of shares received in payment for exercise of stock options			2,771	1,963
Redemption of noncontrolling interest	$ 481	$ 0	481	0
PP&E financed by construction liability			109	187
Property and equipment acquired under capital lease			$ 0	$ 127