NxStage Medical 10-Q 8 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	1-May-14
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Entity Registrant Name	'NxStage Medical, Inc.	'
Entity Central Index Key	'0001333170	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	61,415,670

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$76,829	$84,134
Accounts receivable, net	25,263	20,158
Inventory	40,804	37,801
Prepaid expenses and other current assets	4,098	4,027
Total current assets	146,994	146,120
Property and equipment, net	56,826	52,478
Field equipment, net	14,822	13,041
Deferred cost of revenues	33,815	34,730
Intangible assets, net	16,491	17,194
Goodwill	41,817	41,817
Other assets	1,941	1,582
Total assets	312,706	306,962
Current liabilities:	'	'
Accounts payable	22,310	14,610
Accrued expenses	20,538	21,025
Current portion of long-term debt	103	102
Other current liabilities	1,801	1,870
Total current liabilities	44,752	37,607
Deferred revenues	52,242	53,277
Long-term debt	1,030	1,044
Other long-term liabilities	21,346	20,273
Total liabilities	119,370	112,201
Commitments and contingencies (Note 9)	'	'
Stockholders' equity:	'	'
Undesignated preferred stock: par value $0.001, 5,000,000 shares authorized; no shares issued and outstanding as of March 31, 2014 and December 31, 2013	'	'
Common stock: par value $0.001, 100,000,000 shares authorized; 61,996,196 and 61,666,048 shares issued as of March 31, 2014 and December 31, 2013, respectively	62	61
Additional paid-in capital	571,217	567,468
Accumulated deficit	-368,817	-363,542
Accumulated other comprehensive income	394	212
Treasury stock, at cost: 579,121 and 575,895 shares as of March 31, 2014 and December 31, 2013, respectively	-10,010	-9,963
Total NxStage Medical Inc. stockholders' equity	192,846	194,236
Noncontrolling interest	490	525
Total stockholders' equity	193,336	194,761
Total liabilities and stockholders' equity	$312,706	$306,962

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]	'	'
Undesignated preferred stock, par value	$0.00	$0.00
Undesignated preferred stock, shares authorized	5,000,000	5,000,000
Undesignated preferred stock, shares issued	0	0
Undesignated preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	61,996,196	61,666,048
Treasury stock, shares	579,121	575,895

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Revenues	$72,221	$61,644
Cost of revenues	43,287	37,644
Gross profit	28,934	24,000
Operating expenses:	'	'
Selling and marketing	13,218	10,696
Research and development	5,134	5,108
Distribution	6,550	4,908
General and administrative	8,821	7,824
Total operating expenses	33,723	28,536
Loss from operations	-4,789	-4,536
Other expense:	'	'
Interest expense	-198	-150
Other income (expense), net	23	-176
Total other expenses	-175	-326
Net loss before income taxes	-4,964	-4,862
Provision for income taxes	346	132
Net loss	-5,310	-4,994
Less: Net loss attributable to noncontrolling interests	-35	'
Net loss attributable to stockholders of NxStage Medical, Inc.	-5,275	-4,994
Net loss per share, basic and diluted	($0.09)	($0.08)
Weighted-average shares outstanding, basic and diluted	61,252	59,381
Other comprehensive income	182	145
Total comprehensive loss	-5,128	-4,849
Less: Comprehensive loss attributable to noncontrolling interests	-35	'
Total comprehensive loss attributable to stockholders of NxStage Medical, Inc.	($5,093)	($4,849)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net loss	($5,310)	($4,994)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	6,591	6,080
Stock-based compensation	2,641	2,646
Other	80	230
Changes in operating assets and liabilities:	'	'
Accounts receivable	-5,118	-3,072
Inventory	-8,224	-6,350
Prepaid expenses and other assets	-393	-1,474
Accounts payable	7,702	4,124
Accrued expenses and other liabilities	-339	-216
Deferred revenues	-1,010	-1,887
Net cash used in operating activities	-3,380	-4,913
Cash flows from investing activities:	'	'
Purchases of property and equipment	-4,915	-2,023
Net cash used in investing activities	-4,915	-2,023
Cash flows from financing activities:	'	'
Proceeds from exercise of stock options and warrants and employee stock purchase plan	1,460	731
Repayments on loans and lines of credit	-12	'
Repayments on capital leases	-387	-295
Net cash provided by financing activities	1,061	436
Foreign exchange effect on cash and cash equivalents	-71	-136
Decrease in cash and cash equivalents	-7,305	-6,636
Cash and cash equivalents, beginning of period	84,134	106,439
Cash and cash equivalents, end of period	$76,829	$99,803

Nature_of_Operations

Nature of Operations	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Nature of Operations	'
	1	Nature of Operations
	We are a medical device company that develops, manufactures and markets innovative products for the treatment of kidney failure, fluid overload and related blood treatments and procedures. Our primary product, the System One, was designed to satisfy an unmet clinical need for a system that can deliver the therapeutic flexibility and clinical benefits associated with 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, 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 including more frequent dialysis, which clinical literature suggests provides patients better clinical outcomes and improved quality of life. The System One is cleared or approved for commercial sale in the U.S., Canada and certain other markets, and is CE marked in the EU, for the treatment of acute and chronic kidney failure and fluid overload. The System One is cleared specifically by the U.S. Food and Drug Administration (FDA) for home hemodialysis as well as therapeutic plasma exchange in a clinical environment. The System One is also CE marked in the EU for nocturnal home hemodialysis. We also sell needles and blood tubing sets primarily to dialysis centers for the treatment of end-stage renal disease (ESRD). These products are cleared or approved for commercial sale in the U.S., Canada and certain other markets and are CE marked in the EU. We believe our largest market opportunity is for our System One used in the home dialysis market for the treatment of ESRD. We are operating a small number of NxStage Kidney Care dialysis centers, and plan to open additional centers, focused on supporting home therapy and providing flexible in-center options with NxStage technology as part of our market development activities to increase home therapy access. We continue to make significant investments in marketing, research and development, and these dialysis centers, all of which are intended to help us to further penetrate and expand the market for our products.
	Basis of Presentation
	The accompanying condensed consolidated financial statements as of March 31, 2014 and for the three months then ended, 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, 2013 (2013 Form 10-K) and updated, as necessary, in this Quarterly Report on Form 10-Q. Operating results for any interim period are not necessarily indicative of results for the entire year or future periods. The December 31, 2013 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 2013 Form 10-K.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2	Summary of Significant Accounting Policies
	Principles of Consolidation and Basis of Presentation
	The accompanying condensed consolidated financial statements include the accounts of NxStage Medical, Inc. and our wholly-owned and majority-owned subsidiaries. All material intercompany transactions and balances have been eliminated in consolidation. Certain reclassifications have been made to prior periods’ financial statements to conform to the 2014 presentation.
	Use of Estimates
	The preparation of our condensed consolidated financial statements in conformity with GAAP requires our management to make estimates and assumptions that affect reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Revenue Recognition
	Services Segment
	Revenues in our Services segment are derived from dialysis care services provided to patients at our recently opened NxStage Kidney Care dialysis centers.
	Revenues are recognized based on a usual customary fee schedule, net of estimated contractual allowances to reflect the estimated amounts to be received from the payor. Revenues are recognized in the period in which services are provided when we have the ability to reasonably estimate amounts ultimately collectible from the payor. In instances where we do not have the ability to reasonably estimate amounts ultimately collectible, as is often the case with non-contracted commercial health plans and amounts due from patients (including co-pay and deductible amounts), revenue is recognized in the period in which cash is received.
	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. One customer represented 20% and 19% of accounts receivable at March 31, 2014 and December 31, 2013, respectively.
	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, 2013		$	297
	Provision			122
	Usage			(101	)
	Balance at March 31, 2014		$	318
	Recent Accounting Pronouncements
	Effective January 1, 2014, we adopted Financial Accounting Standards Board Accounting Standards Update No. 2013-11 which impacts the presentation of unrecognized tax benefits on the statement of financial position. As a result, unrecognized tax benefit are presented as a reduction to a deferred tax asset for a net operating loss carryforward, similar tax loss, or a tax credit carryforward. To the extent the tax benefit is not available at the reporting date under the governing tax law or if we do not intend to use the deferred tax asset for such purpose, the unrecognized tax benefit is presented as a liability and not combined with deferred tax assets. The adoption of this standard did not impact our condensed consolidated financial statements, as our practice was consistent with this standard prior to its effective date.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Inventory	'
	3. 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):
		March 31,		December 31,
		2014		2013
	Purchased components	$	17,790	$	15,946
	Work in process		12,918		10,762
	Finished goods		10,096		11,093
	Total	$	40,804	$	37,801

Property_and_Equipment_and_Fie

Property and Equipment and Field Equipment	3 Months Ended
	Mar. 31, 2014
Property Plant And Equipment [Abstract]	'
Property and Equipment and Field Equipment	'
	4. Property and Equipment and Field Equipment
	Accumulated depreciation on property and equipment was $23.3 million and $21.8 million at March 31, 2014 and December 31, 2013, respectively. Accumulated depreciation on field equipment was $37.2 million and $36.7 million at March 31, 2014 and December 31, 2013, respectively.

Intangible_Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]	'
Intangible Assets	'
	5. Intangible Assets
	Accumulated amortization of intangible assets was $18.2 million and $17.5 million at March 31, 2014 and December 31, 2013, respectively.

Net_Loss_Per_Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Net Loss Per Share	'
	6. 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 March 31,
		2014		2013
	Options to purchase common stock		943		981
	Unvested restricted stock		237		155
	Warrants to purchase common stock		—		658
	Total		1,180		1,794

Accrued_expenses_and_Other_lon

Accrued expenses and Other long-term liabilities	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Accrued expenses and Other long-term liabilities	'
	7	Accrued expenses and Other long-term liabilities
	The components of accrued expenses are as follows (in thousands):
			March 31,		December 31,
			2014		2013
	Payroll, compensation and related benefits		$	9,041	$	9,041
	Distribution expenses			2,841		2,762
	General and administrative expenses			1,848		2,207
	Accrued taxes			969		860
	Audit, Legal, and consulting fees			1,803		2,725
	Other			4,036		3,430
	Total		$	20,538	$	21,025
	The components of other long-term liabilities are as follows (in thousands):
			March 31,		December 31,
			2014		2013
	Capital lease obligations		$	14,869	$	14,133
	Lease incentive obligations			3,659		3,589
	Benefit plan obligations			1,847		1,770
	Other			971		781
			$	21,346	$	20,273

Segment_Disclosures

Segment Disclosures	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Disclosures	'
	8	Segment Disclosures
	With our continued investment in our NxStage Kidney Care dialysis centers, effective with the first quarter of 2014, it was determined that the operations of NxStage Kidney Care should be presented separately. Prior to 2014 its operations were included within the Other category. We now 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 distribute our products in three markets: home, critical care and in-center. Prior period information has been updated to conform with the current presentation.
	Our System One segment includes revenues from the sale and rental of the System One and PureFlow SL dialysate preparation equipment and the sale of disposable products in the home and critical care markets. The home market is devoted to the treatment of ESRD patients in the home, 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 internationally. The results of our international business are included in the System One segment
	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.
	Our Services segment includes revenues from dialysis services provided to patients at our NxStage Kidney Care dialysis centers.
	The remainder of our operations and financial information, 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.
	The accounting policies of our reportable segments are described in Note 2 to the consolidated financial statements included in our 2013 Form 10-K 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			Total
															Revenue
															Elimination
	Three Months Ended March 31, 2014
	Revenues from external customers		$	51,135		$	18,916		$	2,054		$	116		$	—		$	72,221
	Intersegment revenues			52			—			—		$	—			(52	)		—
	Revenues			51,187			18,916			2,054			116			(52	)		72,221
	Segment profit (loss)			9,225			2,954			(14,013	)		(2,955	)		—			(4,789	)
	Depreciation and amortization			4,977			276			1,184			154			—			6,591
	Three Months Ended March 31, 2013
	Revenues from external customers		$	42,169		$	18,700		$	775		$	—		$	—			61,644
	Intersegment revenues			—			—			—			—			—			—
	Revenues			42,169			18,700		$	775			—			—			61,644
	Segment profit (loss)			6,513			3,438			(13,603	)		(884	)		—			(4,536	)
	Depreciation and amortization			4,423			345			1,312			—			—			6,080
	The following table presents assets allocated to our reportable segments along with a reconciliation of the total segment assets to total assets (in thousands):
			March 31,			December 31,
			2014			2013
	System One		$	114,924		$	110,486
	In-Center			32,138			26,449
	Services			7,061			4,273
	Total segment assets			154,123			141,208
	Corporate assets:
	Cash and cash equivalents			76,829			84,134
	Property and equipment, net			17,407			17,000
	Intangible assets, net			16,491			17,194
	Goodwill			41,817			41,817
	Prepaid and other assets			6,039			5,609
	Total assets		$	312,706		$	306,962
	Substantially all of our revenues have been 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 to customers located in the U.S.
	The following table summarizes the customers who individually comprise greater than ten percent of total revenues and their respective portion of total revenues:
			Three Months Ended March 31,
			2014			2013
	DaVita			22	%		22	%
	Fresenius			15	%		13	%
	Gambro			10	%		14	%
	Sales to DaVita and Fresenius are in the System One segment. Sales to Gambro are in the In-Center segment. All of Gambro’s sales of our products are to DaVita.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	9	Commitments and Contingencies
	Contingencies
	A civil complaint was filed against us on February 28, 2012 in the U.S. District Court for the District of Massachusetts by Gambro Renal Products, Inc., or Gambro (Case No. 1:12cv10370-PBS). The complaint alleged that we violated Section 43(a) of the Lanham Act, 15 U.S.C. § 1125(a), and Massachusetts General Laws Chapter 93A by making false and misleading statements about our and Gambro’s allegedly competing products in the critical care market in commercial and promotional activities. The complaint also alleged that we wrongfully interfered with contractual and advantageous relationships of Gambro in its critical care business.
	Effective January 2, 2014, we and Gambro agreed to a settlement of this litigation without any admission of wrongdoing or liability by either party and dismissal of all related claims with prejudice. The settlement required us to pay a one-time cash payment to Gambro which was primarily offset by reimbursement from our insurance company. At the same time, we entered into a patent cross-license agreement with Baxter that provides for the cross-license of three patents and the Third Amendment to Extracorporeal Disposables Distribution Agreement that amends the length and other terms of a distribution agreement between us and Gambro. The settlement as a whole can be viewed as a multi-element arrangement as defined by ASC 605-25 Multiple Element Arrangements, which required us to identify and estimate a fair value for each element to properly account for the settlement. We recorded the settlement, reimbursement and consideration of the multi-element arrangement guidance within general and administrative expense on the consolidated statements of comprehensive loss.
	Other significant commitments and contingencies at March 31, 2014 are consistent with those discussed in Note 10 to the consolidated financial statements in our 2013 Form 10-K.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	10	Income Taxes
	The provision for income taxes of $0.3 million and $0.1 million for the three months ended March 31, 2014 and 2013, respectively, relates to the profitable operations of certain foreign subsidiaries. During the first quarter of 2013 we recognized a discrete benefit resulting from a foreign legislative change.
	As of March 31, 2014, we had a liability for unrecognized tax benefits included in the balance sheet of approximately $0.5 million, including accrued interest and penalties of $0.1 million. There have been no significant changes to these amounts during the three months ended March 31, 2014.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	11	Stock-Based Compensation
	Stock-based Compensation Expense
	Our stock-based compensation expense is allocated among the following components of our condensed consolidated statements of comprehensive loss (in thousands):
			Three Months Ended March 31,
			2014		2013
	Cost of revenues		$	198	$	321
	Selling and marketing			855		699
	Research and development			325		447
	General and administrative			1,263		1,179
	Total		$	2,641	$	2,646
	Stock Options and Restricted Stock Units
	The Company granted options to purchase 769,589 and 832,737 shares of common stock during the three months ended March 31, 2014 and 2013, respectively. The weighted-average fair value of options granted during the three months ended March 31, 2014 and 2013 was $5.98 and $6.07 per option, respectively.
	The Company awarded 168,227 and 196,775 restricted stock units during the three months ended March 31, 2014 and 2013, respectively, which vest based on continued employment over a period of four years. The weighted-average fair value of these restricted stock units awarded during the three months ended March 31, 2014 and 2013 was $14.07 and $11.34 per unit, respectively.
	Performance Based Plans
	In March 2014, the Compensation Committee of our Board of Directors approved the grant of up to 369,136 restricted stock units pursuant to performance based awards subject to the achievement of certain Company financial performance metrics for the year ending December 31, 2014. The restricted stock units, if earned, vest over a requisite service period of three years and have a fair value of $14.66 per unit. The estimated expense will be recognized as stock-based compensation expense over the requisite service period based on the number of shares expected to vest.
	Further, in March 2014, the Compensation Committee made awards subject to individual performance and the achievement of certain Company financial performance metrics for the year ending December 31, 2014. Awards are payable in shares of the Company’s common stock or in cash, at the discretion of the Compensation Committee. The estimated payout of these awards is being recognized as compensation expense during 2014, with a portion of this compensation expense classified as stock-based compensation expense, and has been classified as a liability on the Company’s condensed consolidated balance sheet.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Stockholders' Equity	'
	12	Stockholders’ Equity
	We received 3,226 and 20,224 shares of common stock that were surrendered in payment for the exercise of stock options through the three months ended March 31, 2014 and 2013, respectively.

Noncontrolling_Interest

Noncontrolling Interest	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling Interest	'
	13	Noncontrolling Interest
	In 2013, NxStage Kidney Care entered into a joint venture agreement with an unaffiliated not-for-profit dialysis provider operating independent dialysis centers. The other venturer contributed $0.5 million as an initial investment into the joint venture, which is reflected in the condensed consolidated balance sheet as noncontrolling interest. Noncontrolling interest represents the minority shareholder’s proportionate share of the Company’s majority owned subsidiary. The following table sets forth the changes in non-controlling interest for the three months ended March 31, 2014 and 2013 (in thousands):
			Three Months Ended March 31,
			2014			2013
	Balance at beginning of period		$	525		$	—
	Net loss attributable to non-controlling interest in consolidated subsidiary			(35	)		—
	Balance at end of period		$	490		$	—

Derivative_Instruments_and_Hed

Derivative Instruments and Hedging	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Instruments and Hedging	'
	14	Derivative Instruments and Hedging
	We operate a manufacturing and service facility in Mexico where we purchase materials and pay our employees in Pesos, and as such, we are potentially exposed to adverse as well as beneficial movements in foreign currency exchange rates. To minimize the impact of foreign currency exchange rate fluctuations on these Peso denominated expenses, we have entered into foreign exchange forward contracts. These contracts have a duration 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 March 31, 2014 and December 31, 2013, the notional amount of our outstanding contracts that are designated as cash flow hedges was $10.7 million and $10.4 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. These amounts were not material at March 31, 2014 or December 31, 2013.
	Gains or losses related to hedge ineffectiveness recognized in earnings were not material during the three months ended March 31, 2014 or 2013. 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)		Gain (Loss)			Classification within the
			Recognized in OCI		Reclassified from OCI			Condensed Consolidated
			(Effective Portion)		into Income			Statement of
					(Effective Portion)			Comprehensive Loss
	Three Months Ended March 31, 2014
	Foreign exchange forward contracts		$	33	$	(102	)	Cost of revenues
	Three Months Ended March 31, 2013
	Foreign exchange forward contracts		$	566	$	353		Cost of revenues

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive (Loss) Income	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive (Loss) Income	'
	15	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 (loss)			Other (2)		Total
			on derivative
			instruments
	Balance, net of tax, at beginning of period		$	(123	)	$	335	$	212
	Other comprehensive income before reclassifications			33			47		80
	Loss reclassified to earnings (1)			102			—		102
	Total other comprehensive income			135			47		182
	Balance, net of tax, at end of period		$	12		$	382	$	394
	-1	Reclassifications of gains (losses) on derivative instruments are included in cost of revenues on the condensed consolidated statement of comprehensive loss. See Note 14 for further information.
	-2	Other includes cumulative translation adjustments and pension benefits.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	16	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.
	Our contingent consideration liability relates to deferred payments in connection with our acquisition of substantially all of the System One assets of Kimal PLC, a distributor of our products in the United Kingdom, on April 2, 2013. The liability recorded at March 31, 2014 and December 31, 2013 was measured using probability weighted discounted cash flow method and includes certain significant unobservable inputs, namely, a discount rate of 11.5% and patient growth rates.
	We did not have any transfers between Level 1 and Level 2 during the three months ended March 31, 2014.
	The following table presents assets and liabilities measured at fair value on a recurring basis and their level within the value hierarchy (in thousands):
	March 31, 2014		Quoted Prices in			Significant Other		Significant		Total
			Active Markets for			Observable Inputs		Unobservable		Fair Value
			Identical Assets			(Level 2)		Inputs
			(Level 1)					(Level 3)
	Assets
	Money market funds (1)		$	59,779		$	—	$	—	$	59,779
	Foreign exchange forward contracts (2)			—			68		—		68
	Liabilities
	Foreign exchange forward contracts (2)		$	—		$	88	$	—	$	88
	Contingent consideration liability (3)			—			—		278		278
	December 31, 2013		Quoted Prices in			Significant Other		Significant		Total
			Active Markets for			Observable Inputs		Unobservable		Fair Value
			Identical Assets			(Level 2)		Inputs
			(Level 1)					(Level 3)
	Assets
	Money market funds (1)		$	69,779		$	—	$	—	$	69,779
	Foreign exchange forward contracts (2)			—			34		—		34
	Liabilities
	Foreign exchange forward contracts (2)		$	—		$	192	$	—	$	192
	Contingent consideration liability (3)			—			—		540		540
	-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.
	-3	Net present value of expected payments under contingent consideration liability are reported in accrued expenses.
	The following table presents the rollforward of the contingent consideration liability classified as Level 3 within the value hierarchy (in thousands):
	Balance at beginning of period		$	540
	Less: Payments Made			(262	)
	Balance at end of period		$	278
	The carrying amount of our long-term debt approximates fair value at March 31, 2014 and December 31, 2013. 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, 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.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2014
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
	17	Supplemental Cash Flow Information
	The following additional information is provided with respect to the condensed consolidated statements of cash flows (in thousands):
			Three Months Ended March 31,
			2014		2013
	Noncash Investing and Financing Activities:
	Transfers from inventory to field equipment		$	4,987	$	2,505
	Transfers from field equipment to deferred cost of revenues			2,260		1,391
	Payment of corporate bonus in common stock			—		1,034
	Market value of shares received in payment for exercise of stock options			47		226
	Construction-in-process financed by construction liability			969		561

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Principles of Consolidation and Basis of Presentation	'
	Principles of Consolidation and Basis of Presentation
	The accompanying condensed consolidated financial statements include the accounts of NxStage Medical, Inc. and our wholly-owned and majority-owned subsidiaries. All material intercompany transactions and balances have been eliminated in consolidation. Certain reclassifications have been made to prior periods’ financial statements to conform to the 2014 presentation.
Use of Estimates	'
	Use of Estimates
	The preparation of our condensed consolidated financial statements in conformity with GAAP requires our management to make estimates and assumptions that affect reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Revenue Recognition	'
	Revenue Recognition
	Services Segment
	Revenues in our Services segment are derived from dialysis care services provided to patients at our recently opened NxStage Kidney Care dialysis centers.
	Revenues are recognized based on a usual customary fee schedule, net of estimated contractual allowances to reflect the estimated amounts to be received from the payor. Revenues are recognized in the period in which services are provided when we have the ability to reasonably estimate amounts ultimately collectible from the payor. In instances where we do not have the ability to reasonably estimate amounts ultimately collectible, as is often the case with non-contracted commercial health plans and amounts due from patients (including co-pay and deductible amounts), revenue is recognized in the period in which cash is received.
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. One customer represented 20% and 19% of accounts receivable at March 31, 2014 and December 31, 2013, respectively.
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. The following is a rollforward of our warranty accrual (in thousands):
	Balance at December 31, 2013	$	297
	Provision		122
	Usage		(101	)
	Balance at March 31, 2014	$	318
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	Effective January 1, 2014, we adopted Financial Accounting Standards Board Accounting Standards Update No. 2013-11 which impacts the presentation of unrecognized tax benefits on the statement of financial position. As a result, unrecognized tax benefit are presented as a reduction to a deferred tax asset for a net operating loss carryforward, similar tax loss, or a tax credit carryforward. To the extent the tax benefit is not available at the reporting date under the governing tax law or if we do not intend to use the deferred tax asset for such purpose, the unrecognized tax benefit is presented as a liability and not combined with deferred tax assets. The adoption of this standard did not impact our condensed consolidated financial statements, as our practice was consistent with this standard prior to its effective date.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Schedule of Rollforward of Warranty Accrual	'
	The following is a rollforward of our warranty accrual (in thousands):
	Balance at December 31, 2013	$	297
	Provision		122
	Usage		(101	)
	Balance at March 31, 2014	$	318

Inventory_Tables

Inventory (Tables)	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Components of Inventory	'
	The components of inventory are as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Purchased components	$	17,790	$	15,946
	Work in process		12,918		10,762
	Finished goods		10,096		11,093
	Total	$	40,804	$	37,801

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2014
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 March 31,
		2014		2013
	Options to purchase common stock		943		981
	Unvested restricted stock		237		155
	Warrants to purchase common stock		—		658
	Total		1,180		1,794

Accrued_expenses_and_Other_lon1

Accrued expenses and Other long-term liabilities (Tables)	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Components of Accrued Expenses	'
	The components of accrued expenses are as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Payroll, compensation and related benefits	$	9,041	$	9,041
	Distribution expenses		2,841		2,762
	General and administrative expenses		1,848		2,207
	Accrued taxes		969		860
	Audit, Legal, and consulting fees		1,803		2,725
	Other		4,036		3,430
	Total	$	20,538	$	21,025
Schedule of Other Long-term Liabilities	'
	The components of other long-term liabilities are as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Capital lease obligations	$	14,869	$	14,133
	Lease incentive obligations		3,659		3,589
	Benefit plan obligations		1,847		1,770
	Other		971		781
		$	21,346	$	20,273

Segment_Disclosures_Tables

Segment Disclosures (Tables)	3 Months Ended
	Mar. 31, 2014
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			Total
														Revenue
														Elimination
	Three Months Ended March 31, 2014
	Revenues from external customers	$	51,135		$	18,916		$	2,054		$	116		$	—		$	72,221
	Intersegment revenues		52			—			—		$	—			(52	)		—
	Revenues		51,187			18,916			2,054			116			(52	)		72,221
	Segment profit (loss)		9,225			2,954			(14,013	)		(2,955	)		—			(4,789	)
	Depreciation and amortization		4,977			276			1,184			154			—			6,591
	Three Months Ended March 31, 2013
	Revenues from external customers	$	42,169		$	18,700		$	775		$	—		$	—			61,644
	Intersegment revenues		—			—			—			—			—			—
	Revenues		42,169			18,700		$	775			—			—			61,644
	Segment profit (loss)		6,513			3,438			(13,603	)		(884	)		—			(4,536	)
	Depreciation and amortization		4,423			345			1,312			—			—			6,080
Schedule of Assets Allocated to Reportable Segments	'
	The following table presents assets allocated to our reportable segments along with a reconciliation of the total segment assets to total assets (in thousands):
		March 31,			December 31,
		2014			2013
	System One	$	114,924		$	110,486
	In-Center		32,138			26,449
	Services		7,061			4,273
	Total segment assets		154,123			141,208
	Corporate assets:
	Cash and cash equivalents		76,829			84,134
	Property and equipment, net		17,407			17,000
	Intangible assets, net		16,491			17,194
	Goodwill		41,817			41,817
	Prepaid and other assets		6,039			5,609
	Total assets	$	312,706		$	306,962
Summary of Customers Who Individually Comprise Greater than 10% of Total Revenues and Their Respective Portion of Total Revenues	'
	The following table summarizes the customers who individually comprise greater than ten percent of total revenues and their respective portion of total revenues:
		Three Months Ended March 31,
		2014			2013
	DaVita		22	%		22	%
	Fresenius		15	%		13	%
	Gambro		10	%		14	%

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Summary of Stock-Based Compensation Expense in Consolidated Statements of Comprehensive Loss	'
	Our stock-based compensation expense is allocated among the following components of our condensed consolidated statements of comprehensive loss (in thousands):
		Three Months Ended March 31,
		2014		2013
	Cost of revenues	$	198	$	321
	Selling and marketing		855		699
	Research and development		325		447
	General and administrative		1,263		1,179
	Total	$	2,641	$	2,646

Noncontrolling_Interest_Tables

Noncontrolling Interest (Tables)	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Schedule of Changes in Non-controlling Interest	'
	The following table sets forth the changes in non-controlling interest for the three months ended March 31, 2014 and 2013 (in thousands):
		Three Months Ended March 31,
		2014			2013
	Balance at beginning of period	$	525		$	—
	Net loss attributable to non-controlling interest in consolidated subsidiary		(35	)		—
	Balance at end of period	$	490		$	—

Derivative_Instruments_and_Hed1

Derivative Instruments and Hedging (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Effect of Contracts Designated as Cash Flow Hedges on Condensed 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		Gain (Loss) Reclassified			Classification within the
		in OCI		from OCI into Income			Condensed
		(Effective Portion)		(Effective Portion)			Consolidated Statement
							of Comprehensive Loss
	Three Months Ended March 31, 2014
	Foreign exchange forward contracts	$	33	$	(102	)	Cost of revenues
	Three Months Ended March 31, 2013
	Foreign exchange forward contracts	$	566	$	353		Cost of revenues

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive (Loss) Income (Tables)	3 Months Ended
	Mar. 31, 2014
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 (loss)			Other (2)		Total
			on derivative
			instruments
	Balance, net of tax, at beginning of period		$	(123	)	$	335	$	212
	Other comprehensive income before reclassifications			33			47		80
	Loss reclassified to earnings (1)			102			—		102
	Total other comprehensive income			135			47		182
	Balance, net of tax, at end of period		$	12		$	382	$	394
	-1	Reclassifications of gains (losses) on derivative instruments are included in cost of revenues on the condensed consolidated statement of comprehensive loss. See Note 14 for further information.
	-2	Other includes cumulative translation adjustments and pension benefits.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	'
	The following table presents assets and liabilities measured at fair value on a recurring basis and their level within the value hierarchy (in thousands):
	March 31, 2014		Quoted Prices in			Significant Other		Significant		Total Fair Value
			Active Markets for			Observable Inputs		Unobservable
			Identical Assets			(Level 2)		Inputs
			(Level 1)					(Level 3)
	Assets
	Money market funds (1)		$	59,779		$	—	$	—	$	59,779
	Foreign exchange forward contracts (2)			—			68		—		68
	Liabilities
	Foreign exchange forward contracts (2)		$	—		$	88	$	—	$	88
	Contingent consideration liability (3)			—			—		278		278
	December 31, 2013		Quoted Prices in			Significant Other		Significant		Total Fair Value
			Active Markets for			Observable Inputs		Unobservable
			Identical Assets			(Level 2)		Inputs
			(Level 1)					(Level 3)
	Assets
	Money market funds (1)		$	69,779		$	—	$	—	$	69,779
	Foreign exchange forward contracts (2)			—			34		—		34
	Liabilities
	Foreign exchange forward contracts (2)		$	—		$	192	$	—	$	192
	Contingent consideration liability (3)			—			—		540		540
	-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.
	-3	Net present value of expected payments under contingent consideration liability are reported in accrued expenses.
Roll Forward of Contingent Consideration Liability Classified As Level 3 within Value Hierarchy	'
	The following table presents the rollforward of the contingent consideration liability classified as Level 3 within the value hierarchy (in thousands):
	Balance at beginning of period		$	540
	Less: Payments Made			(262	)
	Balance at end of period		$	278

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2014
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):
		Three Months Ended March 31,
		2014		2013
	Noncash Investing and Financing Activities:
	Transfers from inventory to field equipment	$	4,987	$	2,505
	Transfers from field equipment to deferred cost of revenues		2,260		1,391
	Payment of corporate bonus in common stock		—		1,034
	Market value of shares received in payment for exercise of stock options		47		226
	Construction-in-process financed by construction liability		969		561

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (Accounts Receivable [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Accounts Receivable [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable	20.00%	19.00%

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Schedule of Rollforward of Warranty Accrual (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Accounting Policies [Abstract]	'
Balance at December 31, 2013	$297
Provision	122
Usage	-101
Balance at March 31, 2014	$318

Inventory_Components_of_Invent

Inventory - Components of Inventory (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Purchased components	$17,790	$15,946
Work in process	12,918	10,762
Finished goods	10,096	11,093
Total	$40,804	$37,801

Property_and_Equipment_and_Fie1

Property and Equipment and Field Equipment - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property and Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Accumulated depreciation	$23.30	$21.80
Field Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Accumulated depreciation	$37.20	$36.70

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]	'	'
Accumulated amortization of intangible assets	$18.20	$17.50

Net_Loss_per_Share_Schedule_of

Net Loss per Share - Schedule of Anti-dilutive Net Loss Per Share (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total	1,180	1,794
Options to Purchase Common Stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total	943	981
Unvested Restricted Stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total	237	155
Warrants to Purchase Common Stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total	'	658

Accrued_expenses_and_Other_lon2

Accrued expenses and Other long-term liabilities - Components of Accrued Expenses (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]	'	'
Payroll, compensation and related benefits	$9,041	$9,041
Distribution expenses	2,841	2,762
General and administrative expenses	1,848	2,207
Accrued taxes	969	860
Audit, Legal, and consulting fees	1,803	2,725
Other	4,036	3,430
Total	$20,538	$21,025

Accrued_expenses_and_Other_lon3

Accrued expenses and Other long-term liabilities - Schedule of Other Long-term Liabilities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Liabilities Noncurrent [Abstract]	'	'
Capital lease obligations	$14,869	$14,133
Lease incentive obligations	3,659	3,589
Benefit plan obligations	1,847	1,770
Other	971	781
Total other long-term liabilities	$21,346	$20,273

Segment_Disclosures_Additional

Segment Disclosures - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
	Markets
	Segment
Segment Reporting Information [Line Items]	'
Number of reporting segments	3
Number of markets product distributed	3
Prior to January 1, 2014 [Member]	'
Segment Reporting Information [Line Items]	'
Number of reporting segments	2

Segment_Disclosures_Summary_of

Segment Disclosures - Summary of Operating Performance of Reportable Segments (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Revenues	$72,221	$61,644
Segment profit (loss)	-4,789	-4,536
Depreciation and amortization	6,591	6,080
External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	72,221	61,644
Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	'	'
Operating Segments [Member] | System One [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	51,187	42,169
Segment profit (loss)	9,225	6,513
Depreciation and amortization	4,977	4,423
Operating Segments [Member] | System One [Member] | External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	51,135	42,169
Operating Segments [Member] | System One [Member] | Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	52	'
Operating Segments [Member] | In-Center [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	18,916	18,700
Segment profit (loss)	2,954	3,438
Depreciation and amortization	276	345
Operating Segments [Member] | In-Center [Member] | External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	18,916	18,700
Operating Segments [Member] | In-Center [Member] | Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	'	'
Operating Segments [Member] | Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	2,054	775
Segment profit (loss)	-14,013	-13,603
Depreciation and amortization	1,184	1,312
Operating Segments [Member] | Other [Member] | External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	2,054	775
Operating Segments [Member] | Other [Member] | Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	'	'
Operating Segments [Member] | Services [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	116	'
Segment profit (loss)	-2,955	-884
Depreciation and amortization	154	'
Operating Segments [Member] | Services [Member] | External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	116	'
Operating Segments [Member] | Services [Member] | Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	'	'
Intersegment Revenue Elimination [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	-52	'
Segment profit (loss)	'	'
Depreciation and amortization	'	'
Intersegment Revenue Elimination [Member] | External Customer [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	'	'
Intersegment Revenue Elimination [Member] | Intersegment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	($52)	'

Segment_Disclosures_Schedule_o

Segment Disclosures - Schedule of Assets Allocated to Reportable Segments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total assets	$312,706	$306,962	$306,962
Property and equipment, net	56,826	52,478	'
Intangible assets, net	16,491	17,194	'
Goodwill	41,817	41,817	'
Operating Segments [Member]	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total assets	154,123	'	141,208
Operating Segments [Member] | System One [Member]	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total assets	114,924	'	110,486
Operating Segments [Member] | In-Center [Member]	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total assets	32,138	'	26,449
Operating Segments [Member] | Services [Member]	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total assets	7,061	'	4,273
Corporate, Non-Segment [Member]	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Cash and cash equivalents	76,829	'	84,134
Property and equipment, net	17,407	'	17,000
Intangible assets, net	16,491	'	17,194
Goodwill	41,817	'	41,817
Prepaid and other assets	$6,039	'	$5,609

Segment_Disclosures_Summary_of1

Segment Disclosures - Summary of Customers Who Individually Comprise Greater Than 10% of Total Revenues and Their Respective Portion of Total Revenues (Detail) (Sales [Member])	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
DaVita [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of revenues	22.00%	22.00%
Fresenius [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of revenues	15.00%	13.00%
Gambro [Member]	'	'
Revenue, Major Customer [Line Items]	'	'
Percentage of revenues	10.00%	14.00%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]	'	'
Provision for income taxes	$346,000	$132,000
Liability for unrecognized tax benefits	500,000	'
Accrued interest and penalties	100,000	'
Significant change in unrecognized tax benefit	'	'

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock-Based Compensation Expense in Consolidated Statements of Comprehensive Loss (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Total stock-based compensation expense	$2,641	$2,646
Cost of Revenues [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Total stock-based compensation expense	198	321
Selling and Marketing [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Total stock-based compensation expense	855	699
Research and Development [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Total stock-based compensation expense	325	447
General and Administrative [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Total stock-based compensation expense	$1,263	$1,179

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014
	Options to Purchase Common Stock [Member]	Options to Purchase Common Stock [Member]	Restricted Stock Units (RSUs) [Member]	Restricted Stock Units (RSUs) [Member]	Restricted Stock Units (RSUs) [Member]	Restricted Stock Units (RSUs) [Member]
					2014 Performance Share Plans [Member]	2014 Performance Share Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Options, grants in period	769,589	832,737	168,227	196,775	369,136	'
Weighted-average fair value of options granted	$5.98	$6.07	'	'	'	'
Weighted-average fair value of restricted stock units	'	'	$14.07	$11.34	'	$14.66
Restricted stock vests over a requisite service period	'	'	'	'4 years	'	'3 years

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Equity [Abstract]	'	'
Shares surrendered in payment for the exercise of stock options	3,226	20,224

Noncontrolling_Interest_Additi

Noncontrolling Interest - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2014
	JointVenture
Noncontrolling Interest [Abstract]	'	'
Initial investment in joint venture	'	$0.50
Number of joint venture agreements	1	'

Noncontrolling_Interest_Schedu

Noncontrolling Interest - Schedule of Changes in Non-controlling Interest (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Noncontrolling Interest [Abstract]	'	'
Balance at beginning of period	$525	'
Net loss attributable to non-controlling interest in consolidated subsidiary	-35	'
Balance at end of period	$490	'

Derivative_Instruments_and_Hed2

Derivative Instruments and Hedging - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
		Cash Flow Hedges [Member]	Cash Flow Hedges [Member]
Hedging Transactions And Derivative Financial Instruments [Line Items]	'	'	'
Period of cash flow hedges	'12 months	'	'
Notional amount of outstanding contracts	'	$10.70	$10.40

Derivative_Instruments_and_Hed3

Derivative Instruments and Hedging - Effect of Contracts Designated as Cash Flow Hedges on Condensed Consolidated Financial Statements (Detail) (Cost of Revenues [Member], Foreign Exchange Forward Contracts [Member], Cash Flow Hedges [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cost of Revenues [Member] | Foreign Exchange Forward Contracts [Member] | Cash Flow Hedges [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Gain (Loss) Recognized in OCI (Effective Portion)	$33	$566
Gain (Loss) Reclassified from OCI into Income (Effective Portion)	($102)	$353
Classification within the Condensed Consolidated Statement of Comprehensive Loss	'Cost of revenues	'Cost of revenues

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive (Loss) Income - Summary of Additional Information on Accumulated Other Comprehensive (Loss) Income (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Balance, net of tax, at beginning of period	$212	'
Other comprehensive income before reclassifications	80	'
Loss reclassified to earnings	102	'
Total other comprehensive income	182	145
Balance, net of tax, at end of period	394	'
Other [Member]	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Balance, net of tax, at beginning of period	335	'
Other comprehensive income before reclassifications	47	'
Loss reclassified to earnings	'	'
Total other comprehensive income	47	'
Balance, net of tax, at end of period	382	'
Unrealized Gain (Loss) on Derivative Instruments [Member]	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Balance, net of tax, at beginning of period	-123	'
Other comprehensive income before reclassifications	33	'
Loss reclassified to earnings	102	'
Total other comprehensive income	135	'
Balance, net of tax, at end of period	$12	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'	'
Discount rate	11.50%	11.50%

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Significant Unobservable Inputs (Level 3) [Member]	'	'
Liabilities	'	'
Contingent consideration liability	$278	$540
Fair Value Measurements, Recurring Basis [Member]	'	'
Liabilities	'	'
Contingent consideration liability	278	540
Fair Value Measurements, Recurring Basis [Member] | Foreign Exchange Forward Contracts [Member]	'	'
Assets	'	'
Foreign exchange forward contracts	68	34
Liabilities	'	'
Foreign exchange forward contracts	88	192
Fair Value Measurements, Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Liabilities	'	'
Contingent consideration liability	'	'
Fair Value Measurements, Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Exchange Forward Contracts [Member]	'	'
Assets	'	'
Foreign exchange forward contracts	'	'
Liabilities	'	'
Foreign exchange forward contracts	'	'
Fair Value Measurements, Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Liabilities	'	'
Contingent consideration liability	'	'
Fair Value Measurements, Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Forward Contracts [Member]	'	'
Assets	'	'
Foreign exchange forward contracts	68	34
Liabilities	'	'
Foreign exchange forward contracts	88	192
Fair Value Measurements, Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Liabilities	'	'
Contingent consideration liability	278	540
Fair Value Measurements, Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Exchange Forward Contracts [Member]	'	'
Assets	'	'
Foreign exchange forward contracts	'	'
Liabilities	'	'
Foreign exchange forward contracts	'	'
Fair Value Measurements, Recurring Basis [Member] | Money Market Funds [Member]	'	'
Assets	'	'
Money market funds	59,779	69,779
Fair Value Measurements, Recurring Basis [Member] | Money Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Assets	'	'
Money market funds	59,779	69,779
Fair Value Measurements, Recurring Basis [Member] | Money Market Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Assets	'	'
Money market funds	'	'
Fair Value Measurements, Recurring Basis [Member] | Money Market Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Assets	'	'
Money market funds	'	'

Fair_Value_Measurements_Roll_F

Fair Value Measurements - Roll Forward of Contingent Consideration Liability Classified as Level 3 within Value Hierarchy (Detail) (Significant Unobservable Inputs (Level 3) [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Significant Unobservable Inputs (Level 3) [Member]	'
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Balance at beginning of period	$540
Less: Payments Made	-262
Balance at end of period	$278

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Noncash Investing and Financing Activities:	'	'
Transfers from inventory to field equipment	$4,987	$2,505
Transfers from field equipment to deferred cost of revenues	2,260	1,391
Payment of corporate bonus in common stock	'	1,034
Market value of shares received in payment for exercise of stock options	47	226
Construction-in-process financed by construction liability	$969	$561