AtriCure (ATRC) 10-Q 30 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 28, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	ATRC
Entity Registrant Name	AtriCure, Inc.
Entity Central Index Key	1,323,885
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		32,216,424

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 28,714	$ 28,384
Short-term investments	19,712	31,265
Accounts receivable, less allowance for doubtful accounts of $125 and $68, respectively	16,643	17,558
Inventories	16,567	14,257
Other current assets	2,477	2,044
Total current assets	84,113	93,508
Property and equipment, net	27,455	11,552
Long-term investments	10,381	8,894
Intangible assets, net	7,970	8,878
Goodwill	35,386	35,386
Other noncurrent assets	337	186
Total Assets	165,642	158,404
Current liabilities:
Accounts payable	11,174	7,621
Accrued liabilities	14,320	14,041
Other current liabilities and current maturities of capital leases	13,571	3,981
Total current liabilities	39,065	25,643
Capital leases	68	74
Other noncurrent liabilities	1,025	149
Total Liabilities	$ 40,158	$ 25,866
Commitments and contingencies (Note 7)
Stockholders' Equity:
Common stock, $0.001 par value, 90,000 shares authorized and 28,446 and 27,580 issued and outstanding, respectively	$ 28	$ 28
Additional paid-in capital	280,668	271,282
Accumulated other comprehensive loss	(490)	(348)
Accumulated deficit	(154,722)	(138,424)
Total Stockholders' Equity	125,484	132,538
Total Liabilities and Stockholders' Equity	$ 165,642	$ 158,404

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Condensed Consolidated Balance Sheets (Unaudited) [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 125	$ 68
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	28,446,000	27,580,000
Common stock, shares outstanding	28,446,000	27,580,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) [Abstract]
Revenue	$ 31,423	$ 26,678	$ 93,892	$ 78,039
Cost of revenue	8,945	7,786	26,562	22,709
Gross profit	22,478	18,892	67,330	55,330
Operating expenses:
Research and development expenses	6,504	5,033	17,975	13,603
Selling, general and administrative expenses	22,101	14,662	65,445	53,308
Total operating expenses	28,605	19,695	83,420	66,911
Loss from operations	(6,127)	(803)	(16,090)	(11,581)
Other income (expense):
Interest expense	(16)	(24)	(51)	(290)
Interest income	56	27	142	64
Other	(48)	338	(279)	976
Loss before income tax expense	(6,135)	(462)	(16,278)	(10,831)
Income tax expense	6	4	20	36
Net loss	$ (6,141)	$ (466)	$ (16,298)	$ (10,867)
Basic and diluted net loss per share	$ (0.22)	$ (0.02)	$ (0.60)	$ (0.42)
Weighted average shares outstanding-basic and diluted	27,462	26,915	27,190	26,185
Comprehensive loss:
Unrealized gains (losses) on investments	$ 17	$ (20)	$ 56	$ (33)
Foreign currency translation adjustment	36	(390)	(198)	(416)
Other comprehensive income (loss)	53	(410)	(142)	(449)
Net loss	(6,141)	(466)	(16,298)	(10,867)
Comprehensive loss	$ (6,088)	$ (876)	$ (16,440)	$ (11,316)

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net loss	$ (16,298)	$ (10,867)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	6,533	5,704
Depreciation	3,304	2,405
Amortization of intangible assets	908	1,066
Amortization of deferred financing costs	46	99
Loss on disposal of property and equipment	83	11
Realized loss from foreign exchange on intercompany transactions	333
Amortization/accretion on investments	472	322
Change in allowance for doubtful accounts	55	73
Change in value of contingent consideration		(8,032)
Other		95
Changes in operating assets and liabilities:
Accounts receivable	571	(1,785)
Inventories	(2,461)	(4,555)
Other current assets	(449)	833
Accounts payable	2,181	(539)
Accrued liabilities	557	(3,604)
Other noncurrent assets and liabilities	403	(813)
Net cash used in operating activities	(3,762)	(19,587)
Cash flows from investing activities:
Purchases of available-for-sale securities	(19,525)	(31,412)
Sales and maturities of available-for-sale securities	29,174	14,614
Purchases of property and equipment	(8,287)	(4,389)
Increases in property under build-to-suit obligation	(9,128)
Net cash used in investing activities	(7,766)	(21,187)
Cash flows from financing activities:
Proceeds from sale of stock, net of offering costs of $0 and $257, respectively		65,830
Payments on debt and capital leases	(36)	(6,362)
Increases in build-to-suit obligation	9,128
Proceeds from tax incentive loan	340
Payment of debt fees and premium on retirement of debt	(62)	(181)
Proceeds from stock option exercises	2,421	1,657
Shares repurchased for payment of taxes on stock awards	(650)	(198)
Proceeds from issuance of common stock under employee stock purchase plan	906	708
Net cash provided by financing activities	12,047	61,454
Effect of exchange rate changes on cash and cash equivalents	(189)	(46)
Net increase in cash and cash equivalents	330	20,634
Cash and cash equivalents-beginning of period	28,384	14,892
Cash and cash equivalents-end of period	28,714	35,526
Supplemental cash flow information:
Cash paid for interest	4	113
Cash paid for taxes	20	146
Non-cash investing and financing activities:
Accrued purchases of property and equipment	2,442	2,572
Assets acquired through capital lease	$ 50	$ 8

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Condensed Consolidated Statements of Cash Flows (Unaudited) [Abstract]
Offering cost for sale of stock	$ 0	$ 257

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Description of Business and Summary of Significant Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	1. DESC RIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of the Business — AtriCure, Inc. was incorporated in the State of Delaware on October 31, 2000. The “Company” or “AtriCure” consists of AtriCure, Inc. and its wholly-owned subsidiaries. The Company is an innovator in surgical treatments for atrial fibrillation (Afib) and left atrial appendage management (LAAM). The Company sells its products to medical centers globally through a direct sales force and distributors. Basis of Presentation —The accompanying interim financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC). The accompanying interim financial statements are unaudited, but in the opinion of the Company’s management, contain all of the normal, recurring adjustments considered necessary to present fairly the financial position, results of operations and cash flows for the periods presented in conformity with accounting principles generally accepted in the United States of America (GAAP) applicable to interim periods. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been omitted or condensed. The Company believes the disclosures herein are adequate to make the information presented not misleading. Results of operations are not necessarily indicative of the results expected for the full fiscal year or for any future period. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the audited financial statements of the Company included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 filed with the SEC. Principles of Consolidation —The Condensed Consolidated Financial Statements include the accounts of the Company, AtriCure, LLC, the Company’s wholly-owned subsidiary organized in the State of Delaware, Endoscopic Technologies, LLC, the Company’s wholly-owned subsidiary organized in the State of Delaware, and AtriCure Europe B.V. (AtriCure Europe), the Company’s wholly-owned subsidiary incorporated in the Netherlands. All intercompany accounts and transactions have been eliminated in consolidation. Cash and Cash Equivalents —The Company considers highly liquid investments with maturities of three months or less at the date of acquisition as cash equivalents. Investments —The Company places its investments primarily in U.S. Government agencies and securities, corporate bonds and commercial paper. The Company classifies all investments as available-for-sale. Investments with maturities of less than one year are classified as short-term investments. Investments are recorded at fair value, with unrealized gains and losses recorded as accumulated other comprehensive income (loss). The Company recognizes gains and losses when these securities are sold using the specific identification method and includes them in interest income or expense in the Condensed Consolidated Statements of Operations and Comprehensive Loss. Revenue Recognition —The Company accounts for revenue in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 605, “Revenue Recognition” (ASC 605). The Company recognizes revenue when all of the following criteria are met: (i) there is persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured. Pursuant to the Company’s standard terms of sale, revenue is recognized when title to the goods and risk of loss transfers to customers and there are no remaining obligations that will affect the customers’ final acceptance of the sale. Generally, the Company’s standard terms of sale define the transfer of title and risk of loss to occur upon shipment to the respective customer. The Company generally does not maintain any post-shipping obligations to the recipients of the products. No installation, calibration or testing of products is performed by the Company subsequent to shipment to the customer in order to render it operational. Revenue includes shipping and handling revenue of $260 and $236 for the three months ended September 30, 2015 and 2014 , respectively, and $778 and $699 for the nine months ended September 30, 2015 and 2014 , respectively. Cost of freight for shipments made to customers is included in cost of revenue. Sales and other value-added taxes collected from customers and remitted to governmental authorities are excluded from revenue. The Company sells its products primarily through a direct sales force, with certain international markets sold through distributors. Terms of sale are generally consistent for both end-users and distributors except that payment terms are generally net 30 days for end-users and net 60 days for distributors. Sales Returns and Allowances —The Company maintains a provision for sales returns and allowances to account for potential returns of defective or damaged products, products shipped in error and invoice adjustments. The Company estimates such provision quarterly based primarily on a specific identification basis, in addition to estimating a general reserve. Increases to the provision result in a reduction of revenue. The provision is included in accrued liabilities in the Condensed Consolidated Balance Sheets. Allowance for Doubtful Accounts Receivable —The Company evaluates the collectability of accounts receivable in order to determine the appropriate reserve for doubtful accounts. In determining the amount of the reserve, the Company considers aging of account balances, historical credit losses, customer-specific information and other relevant factors. An increase to the allowance for doubtful accounts results in a corresponding increase in expense. The Company reviews accounts receivable and adjusts the allowance based on current circumstances and charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs against the allowance has not been significant. Inventories —Inventories are stated at the lower of cost or market using approximate costs based on the first-in, first-out cost method (FIFO) and consist of raw materials, work in process and finished goods. The Company’s industry is characterized by rapid product development and frequent new product introductions. Uncertain timing of product approvals, variability in product launch strategies and variation in product utilization all impact excess and obsolete inventory. An inventory allowance based on product usage is estimated and recorded quarterly for excess, slow moving and obsolete inventory, as well as inventory with a carrying value in excess of its net realizable value. Write-offs are recorded when a product is destroyed. The Company’s history of write-offs against the allowance has not been significant. Inventories consist of the following: September 30, December 31, 2015 2014 Raw materials $ $ Work in process Finished goods Inventories $ $ Property and Equipment —Property and equipment is stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method of depreciation for financial reporting purposes and applied over the estimated useful lives of the assets. The estimated useful life by major asset category is the following: generators and other capital equipment, machinery, equipment and vehicles is three to seven years, computer and other office equipment is three years, furniture and fixtures is three to seven years and leasehold improvements and equipment leased under a capital lease are the shorter of their useful life or remaining lease term. The Company reassesses the useful lives of property and equipment annually, and assets are retired if they are no longer in service. Maintenance and repair costs are expensed as incurred. Generators and other capital equipment (such as the Company’s switchbox units and cryosurgical consoles) are loaned at no cost to direct customers that use the Company’s disposable products. Depreciation of such assets is included in cost of revenue. The estimated useful lives of this equipment are based on anticipated usage by customers and the timing and impact of expected new technology rollouts by the Company. To the extent the Company experiences changes in the usage of this equipment or introduces new technologies, the estimated useful lives of th e equipment may change in a future period. Depreciation related to these generators was $733 and $593 for the three months ended September 30, 2015 and 2014 , respectively, and $2,026 and $1,552 for the nine months ended September 30, 2015 and 2014 , respectively. As of September 30, 2015 and December 31, 2014 , the net carrying amount of loaned equipment included in net property and equipment in the Condensed Consolidated Balance Sheets was $5,237 and $4,141 , respectively. The Company reviews property and equipment for impairment using its best estimates based on reasonable and supportable assumptions and projections. Intangible Assets —Intangible assets with determinable useful lives are amortized on a straight-line basis over the estimated periods benefited. The Company reviews intangible assets for impairment using its best estimates based on reasonable and supportable assumptions and projections. Goodwill— Goodwill represents the excess of purchase price over the fair value of the net assets acquired in business combinations. The Company tests goodwill for impairment annually on November 30, or more often if impairment indicators are present. The Company’s goodwill is accounted for in a single reporting unit representing the Company as a whole. Other Current Liabilities and Current Maturities of Capital Leases— Other current liabilities consist of a financing obligation related to the construction of the Company’s new headquarters (see Note 7 – Commitments and Contingencies). Current maturities of capital leases consist of capital lease obligations with maturities of less than one year (see Note 6 – Indebtedness). Other Income — Other income consists primarily of foreign currency transaction gains and losses, grant income and non-employee option gains and losses related to the fair market value change for fully vested options outstanding for consultants which are accounted for as free-standing derivatives. The Company recorded net foreign currency transaction gains (losses) of $(48) and ($51) for the three months ended September 30, 2015 and 2014 , respectively, and $(257) and ($30) for the nine months ended September 30, 2015 and 2014 , respectively, in connection with settlements of its intercompany balance with AtriCure Europe and invoices transacted in British Pounds. The Company periodically is awarded grants to support research and development activities or education activities. The Company recognizes grant income when the funds are earned. The Company recorded grant income of $0 and $231 during the three months ended September 30, 2015 and 2014 , respectively. Grant income of $35 and $731 was recorded for the nine months ended September 30, 2015 and 2014 , respectively. The Company historically issued stock options to non-employee consultants as a form of compensation for services provided to the Company. Because the non-employee options require settlement by the Company’s delivery of registered shares and because the tax withholding provisions in the awards allow the options to be partially net-cash settled, these options, when vested, are no longer eligible for equity classification and are, thus, subsequently accounted for as derivative liabilities under FASB ASC 815, “Derivatives and Hedging” (ASC 815) until the awards are ultimately either exercised or forfeited. Accordingly, the vested non-employee options are classified as liabilities and remeasured at fair value through earnings at each reporting period. All vested non-employee options have been exercised as of September 30, 2015 . During the three months ended September 30, 2015 and 2014 , $0 and $158 , respectively, of income was recorded as a result of the remeasurement of the fair value of these fully vested stock options. During the nine months ended September 30, 2015 and 2014 , $(57) and $275 , respectively, of (expense) income was recorded as a result of the remeasurement of the fair value of these fully vested stock options. Taxes — Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period that includes the enactment date. The Company’s estimate of the valuation allowance for deferred tax assets requires it to make significant estimates and judgments about its future operating results. Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more-likely-than-not that some portion of the deferred tax asset will not be realized. Significant weight is given to evidence that can be objectively verified. The Company evaluates deferred tax assets on a quarterly basis to determine if valuation allowances are required by considering all available evidence. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences, future taxable income, exclusive of reversing temporary differences and carryforwards, taxable income in carry-back years and tax planning strategies that are both prudent and feasible. In evaluating whether to record a valuation allowance, the applicable accounting standards deem that the existence of cumulative losses in recent years is a significant piece of objectively verifiable negative evidence that must be overcome by objectively verifiable positive evidence to avoid the need to record a valuation allowance. The Company has recorded a full valuation allowance against its net deferred tax assets as it is more-likely-than-not that the benefit of the deferred tax assets will not be recognized in future periods. A provision of The Patient Protection and Affordable Care Act enacted in 2010, as amended (Affordable Care Act), requires manufacturers of medical devices to pay an excise tax on all U.S. medical device sales. The Company’s expense related to the medical device excise tax, which was recorded in cost of revenue, was $164 and $204 for the three months ended September 30, 2015 and 2014 , respectively, and $468 and $434 for the nine months ended September 30, 2015 and 2014 , respectively. Net Loss Per Share —Basic and diluted net loss per share is computed in accordance with FASB ASC 260, “Earnings Per Share” (ASC 260) by dividing the net loss by the weighted average number of common shares outstanding during the period. Since the Company has experienced net losses for all periods presented, net loss per share excludes the effect of 4,243 and 3,782 options and restricted stock shares as of September 30, 2015 and 2014 , respectively, because they are anti-dilutive. Therefore the number of shares calculated for basic net loss per share is also used for the diluted net loss per share calculation. Comprehensive Loss and Accumulated Other Comprehensive Loss —In addition to net losses, the comprehensive loss includes foreign currency translation adjustments and unrealized gains and losses on investments. Accumulated other comprehensive income (loss) consisted of the following: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total accumulated other comprehensive (loss) income at beginning of period $ $ $ $ Unrealized Gains on Investments Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations — — — — Balance at end of period $ $ $ $ Foreign Currency Translation Adjustment Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations Balance at end of period $ $ $ $ Total accumulated other comprehensive loss at end of period $ $ $ $ Research and Development —Research and development costs are expensed as incurred. These costs include compensation and other internal and external costs associated with the development and research related to new and existing products or concepts, preclinical studies, clinical trials, healthcare compliance and regulatory affairs. Advertising Costs — The Company expenses advertising costs as incurred. Advertising costs were not significant during the three and nine months ended September 30, 2015 and 2014 . Share-Based Compensation —The Company follows FASB ASC 718, “Compensation-Stock Compensation” (ASC 718) to record share-based compensation for all employee share-based payment awards, including stock options, restricted stock, performance shares and stock purchases related to an employee stock purchase plan, based on estimated fair values. The Company’s share-based compensation expense recognized under ASC 718 for the three months ended September 30, 2015 and 2014 was $2,392 and $1,716 , respectively, and $6,533 and $5,704 for the nine months ended September 30, 2015 and 2014 , respectively, on a before and after tax basis. FASB ASC 718 requires companies to estimate the fair value of share-based payment awards on the date of grant using an option-pricing model. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods in the Company’s Condensed Consolidated Statement of Operations and Comprehensive Loss. The expense has been reduced for estimated forfeitures. FASB ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates the fair value of time-based options on the date of grant using the Black-Scholes option-pricing model (Black-Scholes model). The Company’s determination of fair value of share-based payment awards on the date of grant using an option-pricing model is affected by the Company’s stock price, as well as assumptions regarding a number of subjective variables. These variables include, but are not limited to, the Company’s expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors. The fair value of market-based performance option grants is estimated at the date of grant using a Monte-Carlo simulation. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods in the Condensed Consolidated Statements of Operations and Comprehensive Loss. The Company estimates the fair value of restricted stock based upon the grant date closing market price of the Company’s common stock. The Company’s determination of fair value is affected by the Company’s stock price as well as assumptions regarding the number of shares expected to be granted. The Company also has an employee stock purchase plan (ESPP or the Plan) which is available to all eligible employees as defined by the Plan. Under the ESPP, shares of the Company’s common stock may be purchased at a discount. The Company estimates the number of shares to be purchased under the Plan and records compensation expense based upon the fair value of the stock at the beginning of the purchase period using the Black-Scholes model. Use of Estimates —The preparation of the financial statements in conformity with 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 financial statements and the reported amounts of revenue and expense during the reporting period. Actual results could differ from those estimates. Fair Value Disclosures —The Company classifies and records cash and investments in U.S. government agencies and securities as Level 1 within the fair value hierarchy. Accounts receivable, short-term other assets, accounts payable and accrued liabilities are also classified as Level 1. The carrying amounts of these assets and liabilities approximate their fair value due to their relatively short-term nature. Cash equivalents and investments in commercial paper are classified as Level 2 within the fair value hierarchy (see Note 3 – Fair Value for further information). Significant unobservable inputs with respect to the fair value measurement of the Level 3 non-employee stock options are developed using Company data. When an input is changed, the Black-Scholes model is updated and the results are analyzed for reasonableness.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	2. RECENT ACCOUNTING PRONOUNCEMENTS In May 2014 the FASB issued a final standard on revenue from contracts with customers. The standard, issued as FASB ASU 2014-09, “ Revenue from Contracts with Customers” (ASU 2014-09), outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. In July 2015 the FASB decided to defer the effective date of ASU 2014-09 for entities reporting under U.S. GAAP from interim and annual reporting periods beginning after December 15, 2016 to interim and annual reporting periods beginning after December 15, 2017 and allow early adoption as of the original effective date. A full retrospective or modified retrospective approach may be taken to adopt the guidance in the ASU. The Company is evaluating the impact of the provisions of ASU 2014-09 on its consolidated financial position, results of operations and related disclosures. In 2015 the FASB issued ASU 2015-10, “Technical Corrections and Improvements” (ASU 2015-10), which amends a wide range of topics in the FASB Accounting Standards Codification. The amendments make minor corrections or minor improvements to the Codification . The amendments in ASU 2015-10 that require transition guidance are effective for fiscal year s, and interim periods within those fiscal years , beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. All other amendments are effective upon the issuance of ASU 2015-10. The Company has reviewed the amendments in ASU 2015-10 and has determined that the new guidance does not have a material impact on the Company’s financial reporting. In July 2015 the FASB issued ASU 2015-11, “Simplifying the Measurement of Inventory” (ASU 2015-11), which requires entities to measure most inventory at the lower of cost and net realizable value, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market. ASU 2015-11 is effective prospectively for annual periods beginning after December 15, 2016 and interim periods therein. Early application is permitted. The Company is reviewing the provisions of ASU 2015-11 and expects that the new guidance will not have a material impact on the Company’s financial reporting. In August 2015 the FASB issued ASU 2015-15, “Interest – Imputation of Interest” (ASU 2015-15), which clarifies the Security and Exchange Commission staff’s position on presenting and measuring debt issuance costs incurred in connection with line-of-credit arrangements given the lack of guidance on this topic in ASU 2015-03. ASU 2015-15 was effective upon issuance. The Company has determined that the new guidance does not have a material impact on its financial reporting. In September 2015 the FASB issued ASU 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments” (ASU 2015-16), which simplifies the accounting for measurement-period adjustments. Under ASU 2015-16, an acquirer must recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. ASU 2015-16 also requires acquirers to present separately on the face of the income statement, or disclose in the notes, the portion of the amount recorded in current-period earnings by line item that would have been recorded in previous reporting periods if the adjustment to the provisional amounts had been recognized as of the acquisition date. ASU 2015-16 is effective for fiscal years beginning after December 15, 2015, including interim periods within those fiscal years , and must be applied prospectively to adjustments to provisional amounts that occur after the effective date. Early adoption is permitted for financial statements that have not been issued. The Company will consider the new guidance in its accounting and financial reporting for acquisitions.

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2015
Fair Value [Abstract]
Fair Value	3. FAIR VALUE FASB ASC 820, “Fair Value Measurements and Disclosures” (ASC 820) defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value which are the following: · Level 1—Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. An active market for the asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. The valuation under this approach does not entail a significant degree of judgment. · Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The valuation technique for the Company’s Level 2 assets is based on quoted market prices for similar assets from observable pricing sources at the reporting date. · Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Unobservable inputs shall be used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. The fair value of the Company’s Level 3 instruments are estimated on the grant date using the Black-Scholes model and they are revalued at the end of each reporting period using the Black-Scholes model. The fair value of the Company’s Level 3 contingent consideration was estimated on the acquisition date of Endoscopic Technologies, Inc. and was revalued at the end of each subsequent reporting period. In accordance with ASC 820, the following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2015 : Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total Assets: Money market funds $ — $ $ — $ U.S. government agencies and securities — — Corporate bonds — — Total assets $ $ $ — $ There were no changes in the levels or methodology of measurement of financial assets and liabilities during the three or nine month periods ended September 30, 2015 . In accordance with ASC 820, the following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2014 : Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total Assets: Money market funds $ — $ $ — $ Commercial paper — — U.S. government agencies and securities — — Corporate bonds — — Total assets $ $ $ — $ Liabilities: Derivative instruments $ — $ — $ $ Acquisition-related contingent consideration — — — — Total liabilities $ — $ — $ $ There were no changes in the levels or methodology of measurement of financial assets and liabilities during the twelve months ended December 31, 2014 . Derivative Instruments. Vested non-employee options historically issued by the Company were accounted for as derivative liabilities and remeasured at fair value through earnings at each reporting period until exercised or forfeited. All vested non-employee options have been exercised as of September 30, 2015 . In accordance with ASC 820, the following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for derivative instruments as of September 30, 2015 : Beginning Balance – January 1, 2015 $ Total losses included in earnings Exercises Reclassification from equity to liability when fully vested — Ending Balance – September 30, 2015 $ — In accordance with ASC 820, the following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for derivative instruments as of December 31, 2014 : Beginning Balance – January 1, 2014 $ Total gains included in earnings Exercises Reclassification from equity to liability when fully vested — Ending Balance – December 31, 2014 $ Acquisition-Related Contingent Consideration. The Company acquired Endoscopic Technologies, Inc. (Estech) on December 31, 2013. The aggregate consideration paid to Estech shareholders includes up to $26,000 of contingent consideration to be paid based on the achievement of certain performance-based milestones in 2014 and 2015. The fair value of the contingent consideration was estimated using an expected present value approach to estimate an expected value, which, in statistical terms, is the weighted average of a discrete random variable’s possible values with the respective probabilities as the weights. This fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement within the fair value hierarchy. Using this valuation technique, the fair value of the contingent consideration was determined to be $0 as of both September 30, 2015 and December 31, 2014 . The following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for acquisition-related contingent consideration as of December 31, 2014 : Beginning Balance – January 1, 2014 $ Amounts acquired — Transfers in (out) of Level 3 — Changes in fair value included in earnings Ending Balance – December 31, 2014 $ —

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2015
Intangible Assets [Abstract]
Intangible Assets	4. INTANGIBLE ASSETS The following table provides a summary of the Company’s intangible assets with definite lives: September 30, December 31, 2015 2014 Cost Accumulated Amortization Cost Accumulated Amortization Non-compete agreement $ $ $ $ Fusion technology Clamp & probe technology Estech trade name Total $ $ $ $ Amortization expense related to intangible assets with definite lives was $302 and $355 for the three months ended September 30, 2015 and 2014 , respectively, and $908 and $1,066 for the nine months ended September 30, 2015 and 2014 , respectively. Future amortization expense related to intangible assets with definite lives is projected as follows: 2015 $ October 1, 2015 through December 31, 2015 2016 2017 2018 2019 2020 and thereafter Total $

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2015
Accrued Liabilities [Abstract]
Accrued Liabilities	5. ACCRUED LIABILITIES Accrued liabilities consisted of the following: September 30, December 31, 2015 2014 Accrued bonus $ $ Accrued commissions Accrued payroll and employee-related expenses Accrued taxes and value-added taxes payable Accrued royalties Other accrued liabilities Sales returns allowance Accrued non-employee stock options — Total $ $

Indebtedness

Indebtedness	9 Months Ended
	Sep. 30, 2015
Indebtedness [Abstract]
Indebtedness	6. INDEBTEDNESS The Company has a debt agreement with Silicon Valley Bank (SVB). The agreement, as amended, restated and modified, includes a $15,000 revolving credit facility which matures on April 30, 2018 . Borrowing availability under the revolving credit facility is based on the lesser of $15,000 or a borrowing base calculation as defined by the agreement. As of September 30, 2015 the Company had no borrowings under the revolving credit facility and had borrowing availability of $13,292 . Effective March 31, 2015, the Company and SVB entered into an Eighth Loan Modification Agreement (Loan Modification Agreement) which sets forth certain amendments to the Company’s credit facility. The Loan Modification Agreement provides for (i) an increase in the limit of outstanding letters of credit from $1,000 to $2,000 , (ii) an extension of the revolving line maturity date from April 30, 2016 to April 30, 2018 and (iii) modifications to certain covenants and other terms of the agreement. As of December 31, 2014 the Company had an outstanding letter of credit of €75 issued to its European subsidiary’s corporate credit card program provider which was due to expire on June 30, 2015 . The letter of credit was cancelled in June 2015. As of September 30, 2015 the Company had capital leases for computer and office equipment that expire at various terms through 2020 . The cost of the assets under lease was $212 . The assets are depreciated over their estimated useful lives, which equal the terms of the leases. Accumulated amortization on the capital leases was $99 at September 30, 2015. Future maturities on capital lease obligations are projected as follows: 2015 $ October 1, 2015 through December 31, 2015 2016 2017 2018 2019 2020 Total payments $ Imputed interest Net capital lease obligations $

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies [Abstract]
Commitments and Contingencies	7. COMMITMENTS AND CONTINGENCIES Lease Commitments The Company leases various types of office, manufacturing and warehouse facilities and equipment under noncancelable operating leases that expire at various terms through 2030 . In August 2014 the Company and LM-VP AtriCure, LLC (Landlord), a third party unrelated to the Company, entered into a new building lease (Mason Lease) in order to re-locate its corporate headquarters and West Chester, Ohio facilities from their current location to a building to be constructed on Innovation Way in Mason, Ohio and occupied exclusively by the Company. The term of the Mason Lease is fifteen years with three separate five -year renewal options, at the Company’s option, and begins upon substantial completion of the construction of the building (Commencement Date). The Mason Lease commenced in Octo ber 2015. The amount of initial annual base rent of $1,353 is payable monthly beginning on the Commencement Date and is subject to a 2% increase each year during the Lease’s initial term. Upon each renewal, the amount of rent payable will be agreed upon by the Company and Landlord or, if not so agreed upon, by an appraiser. The size of the building subject to the Lease is expected to be approximately 92 square feet. Under the Mason Lease, the Company is responsible for paying real estate taxes, insurance, utilities, operating expenses and most building repairs and maintenance. The Company is also responsible for paying the first $750 of construction-related tenant improvement costs, as well as amounts in excess of the estimated total cost of construction, as defined by the Mason Lease. On the Commencement Date, the Company is required to provide a letter of credit to the Landlord in the amount of $1,250 , which amount may decrease or be removed entirely based on the Company’s financial performance. A letter of credit in the amount of $1,250 was issued subsequent to September 30, 2015. The Company is deemed the owner of the project during the construction period. As a result, approximately $13,507 and $3,941 of project costs incurred to date to construct the building are included in property and equipment and the financing obligation is included in other current liabilities in the Condensed Consolidated Balance Sheets as of September 30, 2015 and December 31, 2014 , respectively. An increase in purchases of building under construction and proceeds from the construction financing obligation are also included in the Condensed Consolidated Statement of Cash Flows as of September 30, 2015 . Royalty Agreements The Company has certain royalty agreements in place with terms that include payment of royalties based on product revenue from sales of specified current products. The royalty agreements have effective dates as early as 2003 and terms ranging from three years to at least twenty years. The royalties range from 0.75% to 5% of specified product sales. One of the agreements includes minimum quarterly payments of $50 through 2015 and a maximum of $2,000 in total royalties over the term of the agreement. Parties to the royalty agreements have the right at any time to terminate the agreement immediately for cause. Royalty expense of $423 and $356 was recorded as part of cost of revenue for the three months ended September 30, 2015 and 2014 , respectively, and $1,321 and $925 was recorded for the nine months ended September 30, 2015 and 2014 . Purchase Agreements The Company enters into standard purchase agreements with certain vendors in the ordinary course of business. Outstanding commitments at September 30, 2015 and 2014 were not significant. Legal The Company may, from time to time, become a party to legal proceedings.

Income Tax Provision

Income Tax Provision	9 Months Ended
	Sep. 30, 2015
Income Tax Provision [Abstract]
Income Tax Provision	8. INCOME TAX PROVISION The Company files federal, state, and foreign income tax returns in jurisdictions with varying statutes of limitations. Income taxes are computed using the asset and liability method in accordance with FASB ASC 740, “Income Taxes”, under which deferred income taxes are provided for the temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities. Deferred taxes are measured using provisions of currently enacted tax laws. A valuation allowance against deferred tax assets is recorded when it is more-likely-than-not that such assets will not be fully realized. The Company has recorded a full valuation allowance against its net deferred tax assets as it is more-likely-than-not that the benefit of the deferred tax assets will not be recognized in future periods. Tax credits are accounted for as a reduction of income taxes in the year in which the credit originates. The Company does not expect any significant unrecognized tax benefits to arise over the next twelve months. The Company’s provision for income taxes for continuing operations in interim periods is computed by applying its estimated annual effective rate against its loss before income tax (expense) benefit for the period. In addition, non-recurring or discrete items are recorded during the period in which they occur. The effective tax rate for the three months ended September 30, 2015 and 2014 was (0.09%) and (0.87%) , respectively. The effective tax rate for the nine months ended September 30, 2015 and 2014 was (0.12%) and (0.33%) , respectively. The Company has not had to accrue any interest and penalties related to unrecognized income tax benefits as a result of offsetting net operating losses. However, if the situation occurs, the Company will recognize interest and penalties within the income tax expense (benefit) line in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Loss and within the related tax liability line in the Condensed Consolidated Balance Sheets.

Equity Compensation Plans

Equity Compensation Plans	9 Months Ended
	Sep. 30, 2015
Equity Compensation Plans [Abstract]
Equity Compensation Plans	9. EQUITY COMPENSATION PLANS The Company has several share-based incentive plans: the 2001 Stock Option Plan (2001 Plan), the 2005 Equity Incentive Plan (2005 Plan), the Amended and Restated 2014 Stock Incentive Plan (2014 Plan) and the 2008 Employee Stock Purchase Plan (ESPP). 2001 Plan, 2005 Plan and 2014 Plan Neither the 2001 Plan nor 2005 Plan is currently used for granting incentives. The Company granted awards under the 2005 Plan until the 2014 Annual Meeting of Stockholders at which stockholders adopted the 2014 Plan. Pursuant to its terms, the 2014 Plan supersedes and replaces the 2005 Plan. Under the 2014 Plan, the Board of Directors may grant incentive stock options to employees and any parent or subsidiary’s employees, and may grant nonstatutory stock options, restricted stock or stock appreciation rights to employees, directors and consultants of the Company and any parent or subsidiary’s employees, directors and consultants. The administrator (currently the Compensation Committee of the Board of Directors) has the power to determine the terms of any awards, including the number of shares subject to each award, the exercisability of the awards and the form of consideration. As of September 30, 2015 , 8,949 shares of common stock had been reserved for issuance under the 2014 Plan. Options granted under the plans generally expire ten years from the date of grant. Options granted from the 2005 Plan and 2014 Plan generally vest at a rate of 25% on the first anniversary date of the grant and ratably each month thereafter over the following three years . Restricted stock awards granted under the 2005 Plan and 2014 Plan generally vest 25% annually over four years from date of grant. Employee Stock Purchase Plan (ESPP) During 2008 the Company established the Employee Stock Purchase Plan which is available to eligible employees as defined in the ESPP. Under the ESPP, shares of the Company’s common stock may be purchased at a discount (currently 15% ) of the lesser of the closing price of the Company’s common stock on the first trading day or the last trading day of the offering period. The offering period (currently six months) and the offering price are subject to change. Participants may not purchase more than $25 of the Company’s common stock in a calendar year and, effective January 1, 2014, may not purchase more than 3 shares during an offering period. Beginning on January 1, 2009 and on the first day of each fiscal year thereafter during the term of the ESPP, the number of shares available for sale under the ESPP shall be increased by the lesser of (i) two percent ( 2% ) of the Company’s outstanding shares of common stock as of the close of business on the last business day of the prior calendar year, not to exceed 600 shares, or (ii) a lesser amount determined by the Board of Directors. At September 30, 2015 there were 524 shares available for future issuance under the ESPP. Expense Information Under FASB ASC 718 The following table summarizes share-based compensation expense related to employee share-based compensation under FASB ASC 718 for the three and nine months ended September 30, 2015 and 2014 . This expense was allocated as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Cost of revenue $ $ $ $ Research and development expenses Selling, general and administrative expenses Total share-based compensation expense related to employees $ $ $ $

Segment and Geographic Informat

Segment and Geographic Information	9 Months Ended
	Sep. 30, 2015
Segment and Geographic Information [Abstract]
Segment and Geographic Information	10. SEGMENT AND GEOGRAPHIC INFORMATION The Company evaluates reporting segments in accordance with FASB ASC 280, “Segment Reporting”. The Company develops, manufactures, and sells devices designed primarily for the surgical ablation of cardiac tissue and systems designed for the exclusion of the left atrial appendage. These devices are developed and marketed to a broad base of medical centers in the United States and internationally. Management considers all such sales to be part of a single reportable segment. Revenue attributed to geographic areas is based on the location of the customers to whom products are sold. Revenue by geographic area was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 United States $ $ $ $ Europe Asia Other international Total international Total revenue $ $ $ $ Domestic revenue by product type was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Open-heart ablation $ $ $ $ Minimally invasive ablation AtriClip Total ablation and AtriClip Valve tools Total domestic $ $ $ $ International revenue by product type was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Open-heart ablation $ $ $ $ Minimally invasive ablation AtriClip Total ablation and AtriClip Valve tools Total international $ $ $ $ The majority of the Company’s long-lived assets are located in the United States.

Public Offerings of Common Stoc

Public Offerings of Common Stock	9 Months Ended
	Sep. 30, 2015
Public Offerings of Common Stock [Abstract]
Public Offerings of Common Stock	11. PUBLIC OFFERINGS OF COMMON STOCK In February 2014 the Company completed a public offering of common stock under its January 2014 shelf registration. The Company sold 3,661 shares of common stock, par value $0.001 per share, at a price of $19.25 per share, generating proceeds of $65,830 after expenses. Offering costs were recorded in additional paid in capital to offset proceeds.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Event [Abstract]
Subsequent Events [Text Block]	12. SUBSEQUENT EVENT On October 13, 2015 the Company acquired nContact Surgical, Inc. (nContact) pursuant to a merger agreement. The Company acquired 100% of the voting equity interests of nContact. The transaction consideration consists of an upfront payment of 3,757 shares of AtriCure common stock and approximately $7,600 in cash, subject to closing adjustments. The transaction also includes up to $50,000 in additional contingent consideration based on completion of enrollment of the CONVERGE IDE trial and PMA approval by December 31, 2020 . Additionally, nContact shareholders are entitled to additional sales-based contingent consideration on revenue in excess of an annual growth rate of more than 25% through 2019 . Subject to the terms and conditions of the merger agreement, all contingent consideration can be paid in either cash or AtriCure common stock, or a combination of both, at the Company’s discretion. The product portfolio acquired includes innovative devices that provide for less invasive ablation options for the treatment of cardiac arrhythmias. The Company expects the combined entity to offer improved market access and additional collaboration opportunities with cardiac surgeons and electrophysiologists. The initial accounting for this acquisition is expected to be completed during the fourth quarter of 2015. Transaction expenses of approximately $526 were recorded as a part of selling, general and administrative expenses during the three and nine months ended September 30, 2015.

Description of Business and S19

Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Description of Business and Summary of Significant Accounting Policies [Abstract]
Nature of the Business	Nature of the Business — AtriCure, Inc. was incorporated in the State of Delaware on October 31, 2000. The “Company” or “AtriCure” consists of AtriCure, Inc. and its wholly-owned subsidiaries. The Company is an innovator in surgical treatments for atrial fibrillation (Afib) and left atrial appendage management (LAAM). The Company sells its products to medical centers globally through a direct sales force and distributors.
Basis of Presentation	Basis of Presentation —The accompanying interim financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (SEC). The accompanying interim financial statements are unaudited, but in the opinion of the Company’s management, contain all of the normal, recurring adjustments considered necessary to present fairly the financial position, results of operations and cash flows for the periods presented in conformity with accounting principles generally accepted in the United States of America (GAAP) applicable to interim periods. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been omitted or condensed. The Company believes the disclosures herein are adequate to make the information presented not misleading. Results of operations are not necessarily indicative of the results expected for the full fiscal year or for any future period. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the audited financial statements of the Company included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 filed with the SEC.
Principles of Consolidation	Principles of Consolidation —The Condensed Consolidated Financial Statements include the accounts of the Company, AtriCure, LLC, the Company’s wholly-owned subsidiary organized in the State of Delaware, Endoscopic Technologies, LLC, the Company’s wholly-owned subsidiary organized in the State of Delaware, and AtriCure Europe B.V. (AtriCure Europe), the Company’s wholly-owned subsidiary incorporated in the Netherlands. All intercompany accounts and transactions have been eliminated in consolidation.
Cash and Cash Equivalents	Cash and Cash Equivalents —The Company considers highly liquid investments with maturities of three months or less at the date of acquisition as cash equivalents.
Investments	Investments —The Company places its investments primarily in U.S. Government agencies and securities, corporate bonds and commercial paper. The Company classifies all investments as available-for-sale. Investments with maturities of less than one year are classified as short-term investments. Investments are recorded at fair value, with unrealized gains and losses recorded as accumulated other comprehensive income (loss). The Company recognizes gains and losses when these securities are sold using the specific identification method and includes them in interest income or expense in the Condensed Consolidated Statements of Operations and Comprehensive Loss.
Revenue Recognition	Revenue Recognition —The Company accounts for revenue in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 605, “Revenue Recognition” (ASC 605). The Company recognizes revenue when all of the following criteria are met: (i) there is persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured. Pursuant to the Company’s standard terms of sale, revenue is recognized when title to the goods and risk of loss transfers to customers and there are no remaining obligations that will affect the customers’ final acceptance of the sale. Generally, the Company’s standard terms of sale define the transfer of title and risk of loss to occur upon shipment to the respective customer. The Company generally does not maintain any post-shipping obligations to the recipients of the products. No installation, calibration or testing of products is performed by the Company subsequent to shipment to the customer in order to render it operational. Revenue includes shipping and handling revenue of $260 and $236 for the three months ended September 30, 2015 and 2014 , respectively, and $778 and $699 for the nine months ended September 30, 2015 and 2014 , respectively. Cost of freight for shipments made to customers is included in cost of revenue. Sales and other value-added taxes collected from customers and remitted to governmental authorities are excluded from revenue. The Company sells its products primarily through a direct sales force, with certain international markets sold through distributors. Terms of sale are generally consistent for both end-users and distributors except that payment terms are generally net 30 days for end-users and net 60 days for distributors.
Sales Returns and Allowances	Sales Returns and Allowances —The Company maintains a provision for sales returns and allowances to account for potential returns of defective or damaged products, products shipped in error and invoice adjustments. The Company estimates such provision quarterly based primarily on a specific identification basis, in addition to estimating a general reserve. Increases to the provision result in a reduction of revenue. The provision is included in accrued liabilities in the Condensed Consolidated Balance Sheets.
Allowance for Doubtful Accounts Receivable	Allowance for Doubtful Accounts Receivable —The Company evaluates the collectability of accounts receivable in order to determine the appropriate reserve for doubtful accounts. In determining the amount of the reserve, the Company considers aging of account balances, historical credit losses, customer-specific information and other relevant factors. An increase to the allowance for doubtful accounts results in a corresponding increase in expense. The Company reviews accounts receivable and adjusts the allowance based on current circumstances and charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs against the allowance has not been significant.
Inventories	Inventories —Inventories are stated at the lower of cost or market using approximate costs based on the first-in, first-out cost method (FIFO) and consist of raw materials, work in process and finished goods. The Company’s industry is characterized by rapid product development and frequent new product introductions. Uncertain timing of product approvals, variability in product launch strategies and variation in product utilization all impact excess and obsolete inventory. An inventory allowance based on product usage is estimated and recorded quarterly for excess, slow moving and obsolete inventory, as well as inventory with a carrying value in excess of its net realizable value. Write-offs are recorded when a product is destroyed. The Company’s history of write-offs against the allowance has not been significant. Inventories consist of the following: September 30, December 31, 2015 2014 Raw materials $ $ Work in process Finished goods Inventories $ $
Property and Equipment	Property and Equipment —Property and equipment is stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method of depreciation for financial reporting purposes and applied over the estimated useful lives of the assets. The estimated useful life by major asset category is the following: generators and other capital equipment, machinery, equipment and vehicles is three to seven years, computer and other office equipment is three years, furniture and fixtures is three to seven years and leasehold improvements and equipment leased under a capital lease are the shorter of their useful life or remaining lease term. The Company reassesses the useful lives of property and equipment annually, and assets are retired if they are no longer in service. Maintenance and repair costs are expensed as incurred. Generators and other capital equipment (such as the Company’s switchbox units and cryosurgical consoles) are loaned at no cost to direct customers that use the Company’s disposable products. Depreciation of such assets is included in cost of revenue. The estimated useful lives of this equipment are based on anticipated usage by customers and the timing and impact of expected new technology rollouts by the Company. To the extent the Company experiences changes in the usage of this equipment or introduces new technologies, the estimated useful lives of th e equipment may change in a future period. Depreciation related to these generators was $733 and $593 for the three months ended September 30, 2015 and 2014 , respectively, and $2,026 and $1,552 for the nine months ended September 30, 2015 and 2014 , respectively. As of September 30, 2015 and December 31, 2014 , the net carrying amount of loaned equipment included in net property and equipment in the Condensed Consolidated Balance Sheets was $5,237 and $4,141 , respectively. The Company reviews property and equipment for impairment using its best estimates based on reasonable and supportable assumptions and projections.
Intangible Assets	Intangible Assets —Intangible assets with determinable useful lives are amortized on a straight-line basis over the estimated periods benefited. The Company reviews intangible assets for impairment using its best estimates based on reasonable and supportable assumptions and projections.
Goodwill	Goodwill— Goodwill represents the excess of purchase price over the fair value of the net assets acquired in business combinations. The Company tests goodwill for impairment annually on November 30, or more often if impairment indicators are present. The Company’s goodwill is accounted for in a single reporting unit representing the Company as a whole.
Other Current Liabilities and Current Maturities of Capital Leases	Other Current Liabilities and Current Maturities of Capital Leases— Other current liabilities consist of a financing obligation related to the construction of the Company’s new headquarters (see Note 7 – Commitments and Contingencies). Current maturities of capital leases consist of capital lease obligations with maturities of less than one year (see Note 6 – Indebtedness).
Other Income	Other Income — Other income consists primarily of foreign currency transaction gains and losses, grant income and non-employee option gains and losses related to the fair market value change for fully vested options outstanding for consultants which are accounted for as free-standing derivatives. The Company recorded net foreign currency transaction gains (losses) of $(48) and ($51) for the three months ended September 30, 2015 and 2014 , respectively, and $(257) and ($30) for the nine months ended September 30, 2015 and 2014 , respectively, in connection with settlements of its intercompany balance with AtriCure Europe and invoices transacted in British Pounds. The Company periodically is awarded grants to support research and development activities or education activities. The Company recognizes grant income when the funds are earned. The Company recorded grant income of $0 and $231 during the three months ended September 30, 2015 and 2014 , respectively. Grant income of $35 and $731 was recorded for the nine months ended September 30, 2015 and 2014 , respectively. The Company historically issued stock options to non-employee consultants as a form of compensation for services provided to the Company. Because the non-employee options require settlement by the Company’s delivery of registered shares and because the tax withholding provisions in the awards allow the options to be partially net-cash settled, these options, when vested, are no longer eligible for equity classification and are, thus, subsequently accounted for as derivative liabilities under FASB ASC 815, “Derivatives and Hedging” (ASC 815) until the awards are ultimately either exercised or forfeited. Accordingly, the vested non-employee options are classified as liabilities and remeasured at fair value through earnings at each reporting period. All vested non-employee options have been exercised as of September 30, 2015 . During the three months ended September 30, 2015 and 2014 , $0 and $158 , respectively, of income was recorded as a result of the remeasurement of the fair value of these fully vested stock options. During the nine months ended September 30, 2015 and 2014 , $(57) and $275 , respectively, of (expense) income was recorded as a result of the remeasurement of the fair value of these fully vested stock options.
Taxes	Taxes — Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period that includes the enactment date. The Company’s estimate of the valuation allowance for deferred tax assets requires it to make significant estimates and judgments about its future operating results. Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more-likely-than-not that some portion of the deferred tax asset will not be realized. Significant weight is given to evidence that can be objectively verified. The Company evaluates deferred tax assets on a quarterly basis to determine if valuation allowances are required by considering all available evidence. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences, future taxable income, exclusive of reversing temporary differences and carryforwards, taxable income in carry-back years and tax planning strategies that are both prudent and feasible. In evaluating whether to record a valuation allowance, the applicable accounting standards deem that the existence of cumulative losses in recent years is a significant piece of objectively verifiable negative evidence that must be overcome by objectively verifiable positive evidence to avoid the need to record a valuation allowance. The Company has recorded a full valuation allowance against its net deferred tax assets as it is more-likely-than-not that the benefit of the deferred tax assets will not be recognized in future periods. A provision of The Patient Protection and Affordable Care Act enacted in 2010, as amended (Affordable Care Act), requires manufacturers of medical devices to pay an excise tax on all U.S. medical device sales. The Company’s expense related to the medical device excise tax, which was recorded in cost of revenue, was $164 and $204 for the three months ended September 30, 2015 and 2014 , respectively, and $468 and $434 for the nine months ended September 30, 2015 and 2014 , respectively.
Net Loss Per Share	Net Loss Per Share —Basic and diluted net loss per share is computed in accordance with FASB ASC 260, “Earnings Per Share” (ASC 260) by dividing the net loss by the weighted average number of common shares outstanding during the period. Since the Company has experienced net losses for all periods presented, net loss per share excludes the effect of 4,243 and 3,782 options and restricted stock shares as of September 30, 2015 and 2014 , respectively, because they are anti-dilutive. Therefore the number of shares calculated for basic net loss per share is also used for the diluted net loss per share calculation.
Comprehensive Loss and Accumulated Other Comprehensive Loss	Comprehensive Loss and Accumulated Other Comprehensive Loss —In addition to net losses, the comprehensive loss includes foreign currency translation adjustments and unrealized gains and losses on investments. Accumulated other comprehensive income (loss) consisted of the following: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total accumulated other comprehensive (loss) income at beginning of period $ $ $ $ Unrealized Gains on Investments Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations — — — — Balance at end of period $ $ $ $ Foreign Currency Translation Adjustment Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations Balance at end of period $ $ $ $ Total accumulated other comprehensive loss at end of period $ $ $ $
Research and Development	Research and Development —Research and development costs are expensed as incurred. These costs include compensation and other internal and external costs associated with the development and research related to new and existing products or concepts, preclinical studies, clinical trials, healthcare compliance and regulatory affairs.
Advertising Costs	Advertising Costs — The Company expenses advertising costs as incurred. Advertising costs were not significant during the three and nine months ended September 30, 2015 and 2014 .
Share-Based Compensation	Share-Based Compensation —The Company follows FASB ASC 718, “Compensation-Stock Compensation” (ASC 718) to record share-based compensation for all employee share-based payment awards, including stock options, restricted stock, performance shares and stock purchases related to an employee stock purchase plan, based on estimated fair values. The Company’s share-based compensation expense recognized under ASC 718 for the three months ended September 30, 2015 and 2014 was $2,392 and $1,716 , respectively, and $6,533 and $5,704 for the nine months ended September 30, 2015 and 2014 , respectively, on a before and after tax basis. FASB ASC 718 requires companies to estimate the fair value of share-based payment awards on the date of grant using an option-pricing model. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods in the Company’s Condensed Consolidated Statement of Operations and Comprehensive Loss. The expense has been reduced for estimated forfeitures. FASB ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates the fair value of time-based options on the date of grant using the Black-Scholes option-pricing model (Black-Scholes model). The Company’s determination of fair value of share-based payment awards on the date of grant using an option-pricing model is affected by the Company’s stock price, as well as assumptions regarding a number of subjective variables. These variables include, but are not limited to, the Company’s expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors. The fair value of market-based performance option grants is estimated at the date of grant using a Monte-Carlo simulation. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods in the Condensed Consolidated Statements of Operations and Comprehensive Loss. The Company estimates the fair value of restricted stock based upon the grant date closing market price of the Company’s common stock. The Company’s determination of fair value is affected by the Company’s stock price as well as assumptions regarding the number of shares expected to be granted. The Company also has an employee stock purchase plan (ESPP or the Plan) which is available to all eligible employees as defined by the Plan. Under the ESPP, shares of the Company’s common stock may be purchased at a discount. The Company estimates the number of shares to be purchased under the Plan and records compensation expense based upon the fair value of the stock at the beginning of the purchase period using the Black-Scholes model.
Use of Estimates	Use of Estimates —The preparation of the financial statements in conformity with 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 financial statements and the reported amounts of revenue and expense during the reporting period. Actual results could differ from those estimates.
Fair Value Disclosures	Fair Value Disclosures —The Company classifies and records cash and investments in U.S. government agencies and securities as Level 1 within the fair value hierarchy. Accounts receivable, short-term other assets, accounts payable and accrued liabilities are also classified as Level 1. The carrying amounts of these assets and liabilities approximate their fair value due to their relatively short-term nature. Cash equivalents and investments in commercial paper are classified as Level 2 within the fair value hierarchy (see Note 3 – Fair Value for further information). Significant unobservable inputs with respect to the fair value measurement of the Level 3 non-employee stock options are developed using Company data. When an input is changed, the Black-Scholes model is updated and the results are analyzed for reasonableness.

Description of Business and S20

Description of Business and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2015
Description of Business and Summary of Significant Accounting Policies [Abstract]
Inventories	September 30, December 31, 2015 2014 Raw materials $ $ Work in process Finished goods Inventories $ $
Accumulated Other Comprehensive Income (Loss)	Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Total accumulated other comprehensive (loss) income at beginning of period $ $ $ $ Unrealized Gains on Investments Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations — — — — Balance at end of period $ $ $ $ Foreign Currency Translation Adjustment Balance at beginning of period $ $ $ $ Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations Balance at end of period $ $ $ $ Total accumulated other comprehensive loss at end of period $ $ $ $

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value [Abstract]
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	In accordance with ASC 820, the following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2015 : Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total Assets: Money market funds $ — $ $ — $ U.S. government agencies and securities — — Corporate bonds — — Total assets $ $ $ — $ There were no changes in the levels or methodology of measurement of financial assets and liabilities during the three or nine month periods ended September 30, 2015 . In accordance with ASC 820, the following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2014 : Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total Assets: Money market funds $ — $ $ — $ Commercial paper — — U.S. government agencies and securities — — Corporate bonds — — Total assets $ $ $ — $ Liabilities: Derivative instruments $ — $ — $ $ Acquisition-related contingent consideration — — — — Total liabilities $ — $ — $ $ There were no changes in the levels or methodology of measurement of financial assets and liabilities during the twelve months ended December 31, 2014 .
Level 3 Fair Value Measurements Using Significant Other Unobservable Inputs for Derivative Instruments	In accordance with ASC 820, the following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for derivative instruments as of September 30, 2015 : Beginning Balance – January 1, 2015 $ Total losses included in earnings Exercises Reclassification from equity to liability when fully vested — Ending Balance – September 30, 2015 $ — In accordance with ASC 820, the following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for derivative instruments as of December 31, 2014 : Beginning Balance – January 1, 2014 $ Total gains included in earnings Exercises Reclassification from equity to liability when fully vested — Ending Balance – December 31, 2014 $
Level 3 Fair Value Measurements Using Significant Other Unobservable Inputs for Acquisition-Related Contingent Consideration	Beginning Balance – January 1, 2014 $ Amounts acquired — Transfers in (out) of Level 3 — Changes in fair value included in earnings Ending Balance – December 31, 2014 $ —

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Intangible Assets [Abstract]
Company's Intangible Assets with Definite Lives	September 30, December 31, 2015 2014 Cost Accumulated Amortization Cost Accumulated Amortization Non-compete agreement $ $ $ $ Fusion technology Clamp & probe technology Estech trade name Total $ $ $ $
Future Amortization Expense Related to Intangible Assets with Definite Lives	2015 $ October 1, 2015 through December 31, 2015 2016 2017 2018 2019 2020 and thereafter Total $

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2015
Accrued Liabilities [Abstract]
Accrued Liabilities	September 30, December 31, 2015 2014 Accrued bonus $ $ Accrued commissions Accrued payroll and employee-related expenses Accrued taxes and value-added taxes payable Accrued royalties Other accrued liabilities Sales returns allowance Accrued non-employee stock options — Total $ $

Indebtedness (Tables)

Indebtedness (Tables)	9 Months Ended
	Sep. 30, 2015
Indebtedness [Abstract]
Future Maturities on Capital Lease Obligations	2015 $ October 1, 2015 through December 31, 2015 2016 2017 2018 2019 2020 Total payments $ Imputed interest Net capital lease obligations $

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2015
Equity Compensation Plans [Abstract]
Share-Based Compensation Expense Related to Employee Share-Based Compensation	Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Cost of revenue $ $ $ $ Research and development expenses Selling, general and administrative expenses Total share-based compensation expense related to employees $ $ $ $

Segment and Geographic Inform26

Segment and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment and Geographic Information [Abstract]
Revenue by Geographic Area	Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 United States $ $ $ $ Europe Asia Other international Total international Total revenue $ $ $ $
Revenue by Product Type	Domestic revenue by product type was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Open-heart ablation $ $ $ $ Minimally invasive ablation AtriClip Total ablation and AtriClip Valve tools Total domestic $ $ $ $ International revenue by product type was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 Open-heart ablation $ $ $ $ Minimally invasive ablation AtriClip Total ablation and AtriClip Valve tools Total international $ $ $ $

Description of Business and S27

Description of Business and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Description Of Business And Significant Accounting Policies [Line Items]
Shipping and handling revenue	$ 260	$ 236	$ 778	$ 699
Payment terms for end-users			30 days
Payment terms for distributors			60 days
Depreciation			$ 3,304	2,405
Net carrying amount of loaned equipment	27,455		27,455		$ 11,552
Grant income	0	231	35	731
(Income) expense related to remeasurement of fair value of fully vested stock options	0	158	(57)	275
Company's expense related to the medical device excise tax	164	204	$ 468	$ 434
Options, restricted stock and performance based shares excluded from calculation of net loss per share			4,243	3,782
Share-based compensation expense recognized	2,392	1,716	$ 6,533	$ 5,704
Subsidiaries [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Net foreign currency transaction (losses) gains	(48)	(51)	$ (257)	(30)
Computer and Other Office Equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category			3 years
Generators [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Depreciation	733	$ 593	$ 2,026	$ 1,552
Carrying Amount of Loaned Equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Net carrying amount of loaned equipment	$ 5,237		$ 5,237		$ 4,141
Short-term Debt [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Maturity period of short term investment			1 year
Minimum [Member] | Generators and Other Capital Equipment, Machinery, Equipment and Vehicles [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category			3 years
Minimum [Member] | Furniture and Fixtures [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category			3 years
Maximum [Member] | Generators and Other Capital Equipment, Machinery, Equipment and Vehicles [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category			7 years
Maximum [Member] | Furniture and Fixtures [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Estimated useful life by major asset category			7 years

Description of Business and S28

Description of Business and Summary of Significant Accounting Policies (Inventories) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Description of Business and Summary of Significant Accounting Policies [Abstract]
Raw materials	$ 5,371	$ 4,429
Work in process	1,013	1,397
Finished goods	10,183	8,431
Inventories	$ 16,567	$ 14,257

Description of Business and S29

Description of Business and Summary of Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (543)	$ (178)	$ (348)	$ (139)
Ending Balance	(490)	(588)	(490)	(588)
Unrealized Gains on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(15)	(19)	(54)	(6)
Other comprehensive income (loss) before reclassifications	$ 17	$ (20)	$ 56	$ (33)
Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations
Ending Balance	$ 2	$ (39)	$ 2	$ (39)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(528)	(159)	(294)	(133)
Other comprehensive income (loss) before reclassifications	67	(339)	135	(386)
Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations	(31)	(51)	(333)	(30)
Ending Balance	$ (492)	$ (549)	$ (492)	$ (549)

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Other Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration	$ 0	$ 0
Maximum [Member] | Estech [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration			$ 26,000

Fair Value (Financial Assets an

Fair Value (Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Significant Other Unobservable Inputs (Level 3) [Member]
Liabilities:
Acquisition-related contingent consideration	$ 0	$ 0
Fair Value, Measurements, Recurring [Member]
Assets:
Total assets	53,011	63,851
Liabilities:
Derivative instruments		$ 120
Acquisition-related contingent consideration
Total liabilities		$ 120
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Assets:
Total assets	22,918	23,692
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Assets:
Total assets		1,800
Fair Value, Measurements, Recurring [Member] | U.S. Government Agencies and Securities [Member]
Assets:
Total assets	1,615	3,022
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Assets:
Total assets	28,478	35,337
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total assets	1,615	$ 3,022
Liabilities:
Acquisition-related contingent consideration
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Government Agencies and Securities [Member]
Assets:
Total assets	1,615	$ 3,022
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total assets	51,396	$ 60,829
Liabilities:
Acquisition-related contingent consideration
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Assets:
Total assets	22,918	$ 23,692
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commercial Paper [Member]
Assets:
Total assets		1,800
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Assets:
Total assets	$ 28,478	35,337
Fair Value, Measurements, Recurring [Member] | Significant Other Unobservable Inputs (Level 3) [Member]
Liabilities:
Derivative instruments		$ 120
Acquisition-related contingent consideration
Total liabilities		$ 120

Fair Value (Level 3 Fair Value

Fair Value (Level 3 Fair Value Measurements Using Significant Other Unobservable Inputs for Derivative Instruments) (Details) - Significant Other Unobservable Inputs (Level 3) [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 120	$ 350
Total (gains) losses included in earnings	57	(183)
Exercises	$ (177)	$ (47)
Reclassification from equity to liability when fully vested
Ending Balance		$ 120

Fair Value (Level 3 Fair Valu33

Fair Value (Level 3 Fair Value Measurements Using Significant Other Unobservable Inputs for Acquisition-Related Contingent Consideration) (Details) - Significant Other Unobservable Inputs (Level 3) [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2014USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 8,032
Amounts acquired
Transfers in (out) of Level 3
Changes in fair value included in earnings	$ (8,032)
Ending Balance

Intangible Assets (Narative) (D

Intangible Assets (Narative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Intangible Assets [Abstract]
Amortization of intangible assets	$ 302	$ 355	$ 908	$ 1,066

Intangible Assets (Company's In

Intangible Assets (Company's Intangible Assets with Definite Lives) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Cost	$ 10,379	$ 10,379
Accumulated Amortization	2,409	1,501
Non-Compete Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	100	100
Accumulated Amortization	100	93
Fusion Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	9,242	9,242
Accumulated Amortization	1,617	924
Clamp and Probe Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	829	829
Accumulated Amortization	484	276
Estech Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	208	208
Accumulated Amortization	$ 208	$ 208

Intangible Assets (Future Amort

Intangible Assets (Future Amortization Expense Related to Intangible Assets with Definite Lives) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Intangible Assets [Abstract]
Expected amortization expense October 1, 2015 through December 31, 2015	$ 300
Expected amortization expense in 2016	1,201
Expected amortization expense in 2017	924
Expected amortization expense in 2018	924
Expected amortization expense in 2019	924
Expected amortization expense in 2020 and thereafter	3,697
Total	$ 7,970	$ 8,878

Accrued Liabilities (Accrued Li

Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accrued Liabilities [Abstract]
Accrued bonus	$ 5,082	$ 4,915
Accrued commissions	4,526	4,477
Accrued payroll and employee-related expenses	3,195	2,281
Accrued taxes and value-added taxes payable	725	1,272
Accrued royalties	361	442
Other accrued liabilities	298	399
Sales returns allowance	133	135
Accrued non-employee stock options		120
Total	$ 14,320	$ 14,041

Indebtedness (Narrative) (Detai

Indebtedness (Narrative) (Details) € in Thousands, $ in Thousands	Mar. 31, 2015USD ($)	Mar. 30, 2015USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2014EUR (€)
Line of Credit Facility [Line Items]
Cost of assets under lease			$ 212
Accumulated amortization on the capital leases			99
Silicon Valley Bank Agreement [Member] | Letter of Credit [Member]
Line of Credit Facility [Line Items]
Credit facility	$ 2,000	$ 1,000
Silicon Valley Bank Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility			$ 15,000
Credit facility maturity date	Apr. 30, 2018	Apr. 30, 2016	Apr. 30, 2018
Borrowings under the revolving credit facility, availability			$ 0
Borrowings under the revolving credit facility, outstanding			$ 13,292
Corporate Credit Card [Member]
Line of Credit Facility [Line Items]
Credit facility maturity date			Jun. 30, 2015
Letter of credit outstanding | €				€ 75
Computer And Office Equipment [Member]
Line of Credit Facility [Line Items]
Capital lease expiration period			Dec. 31, 2020

Indebtedness (Future Maturities

Indebtedness (Future Maturities on Capital Lease Obligations) (Details) $ in Thousands	Sep. 30, 2015USD ($)
Indebtedness [Abstract]
Capital lease obligations due October 1, 2015 through December 31, 2015	$ 14
Capital lease obligations due 2016	55
Capital lease obligations due 2017	35
Capital lease obligations due 2018	21
Capital lease obligations due 2019	11
Capital lease obligations due 2020	4
Capital lease obligations total payments	140
Imputed interest	(10)
Net capital lease obligations	$ 130

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) $ in Thousands	Oct. 01, 2015USD ($)	Sep. 30, 2015USD ($)ft²	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)ft²loan	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Commitments and Contingencies [Line Items]
Royalty expense		$ 423	$ 356	$ 1,321	$ 925
Subsequent Event [Member]
Commitments and Contingencies [Line Items]
Letter of credit to be issued to landlord	$ 1,250
Minimum [Member]
Commitments and Contingencies [Line Items]
Royalty rates				0.75%
Royalty payments, quarterly		50		$ 50
Royalty agreement term				3 years
Maximum [Member]
Commitments and Contingencies [Line Items]
Letter of credit required to landlord				$ 1,250
Royalty rates				5.00%
Royalty payments, quarterly		$ 2,000		$ 2,000
Royalty agreement term				20 years
Office, Manufacturing, Warehouse Facilities, And Equipment [Member]
Commitments and Contingencies [Line Items]
Operating leases expire at various terms				Dec. 31, 2030
Mason Lease [Member]
Commitments and Contingencies [Line Items]
Lease term period				15 years
Number of renewal options | loan				3
Lease renewal option period				5 years
Initial annual base rent				$ 1,353
Lease rate increase, percentage		2.00%		2.00%
Area of lease | ft²		92		92
Project cost included in the construction of building				$ 13,507		$ 3,941
Mason Lease [Member] | Leasehold Improvements [Member]
Commitments and Contingencies [Line Items]
Leases payable, amount		$ 750		$ 750

Income Tax Provision (Narrative

Income Tax Provision (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Provision [Abstract]
Effective tax rate	(0.09%)	(0.87%)	(0.12%)	(0.33%)

Equity Compensation Plans (Narr

Equity Compensation Plans (Narrative) (Details) shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Description of participants purchase limit	Participants may not purchase more than $25 of the Company's common stock in a calendar year and, effective January 1, 2014, may not purchase more than 3 shares during an offering period.
Participants purchase limit shares	3
Offering period	6 months
2001 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiry of options from the date of grant	10 years
2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiry of options from the date of grant	10 years
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance	8,949
Expiry of options from the date of grant	10 years
2008 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's common stock may be purchased at a discount	15.00%
Participants purchase limit value | $	$ 25
Shares available for sale under the ESPP increased	2.00%
Outstanding shares of common stock exceed	600
Shares available for future issuance under the ESPP	524
Employee Stock Option [Member] | 2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period beginning	3 years
Employee Stock Option [Member] | 2005 Plan [Member] | First Anniversary Date Of Grant And Ratably Each Month Thereafter For Three Years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	25.00%
Employee Stock Option [Member] | 2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period beginning	3 years
Employee Stock Option [Member] | 2014 Plan [Member] | First Anniversary Date Of Grant And Ratably Each Month Thereafter For Three Years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	25.00%
Restricted Stock [Member] | 2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted from the 2005 Plan generally vest	4 years
Restricted Stock [Member] | 2005 Plan [Member] | Four Years From Date Of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	25.00%
Restricted Stock [Member] | 2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted from the 2005 Plan generally vest	4 years
Restricted Stock [Member] | 2014 Plan [Member] | Four Years From Date Of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	25.00%

Equity Compensation Plans (Shar

Equity Compensation Plans (Share-Based Compensation Expense Related to Employee Share-Based Compensation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense related to employees	$ 2,392	$ 1,716	$ 6,533	$ 5,704
Cost of Revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense related to employees	112	86	308	250
Research and Development Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense related to employees	374	276	1,010	675
Selling, General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense related to employees	$ 1,906	$ 1,354	$ 5,215	$ 4,779

Segment and Geographic Inform44

Segment and Geographic Information (Revenue by Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 31,423	$ 26,678	$ 93,892	$ 78,039
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	24,665	20,060	73,332	58,106
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	3,972	4,576	12,510	13,183
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,609	1,870	7,447	6,341
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	177	172	603	409
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 6,758	$ 6,618	$ 20,560	$ 19,933

Segment and Geographic Inform45

Segment and Geographic Information (Revenue by Product Type) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue from External Customer [Line Items]
Revenue	$ 31,423	$ 26,678	$ 93,892	$ 78,039
United States [Member]
Revenue from External Customer [Line Items]
Revenue	24,665	20,060	73,332	58,106
United States [Member] | Open-heart Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	13,041	11,265	39,043	32,498
United States [Member] | Minimally Invasive Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	5,011	3,933	14,415	11,774
United States [Member] | AtriClip [Member]
Revenue from External Customer [Line Items]
Revenue	5,927	4,285	17,716	11,856
United States [Member] | Ablation and AtriClip [Member]
Revenue from External Customer [Line Items]
Revenue	23,979	19,483	71,174	56,128
United States [Member] | Valve Tools [Member]
Revenue from External Customer [Line Items]
Revenue	686	577	2,158	1,978
International [Member]
Revenue from External Customer [Line Items]
Revenue	6,758	6,618	20,560	19,933
International [Member] | Open-heart Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	4,092	4,150	12,396	12,175
International [Member] | Minimally Invasive Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	1,945	1,804	5,771	5,773
International [Member] | AtriClip [Member]
Revenue from External Customer [Line Items]
Revenue	598	543	2,058	1,390
International [Member] | Ablation and AtriClip [Member]
Revenue from External Customer [Line Items]
Revenue	6,635	6,497	20,225	19,338
International [Member] | Valve Tools [Member]
Revenue from External Customer [Line Items]
Revenue	$ 123	$ 121	$ 335	$ 595

Public Offerings of Common St46

Public Offerings of Common Stock (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	9 Months Ended
	Feb. 28, 2014	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Public Offerings of Common Stock [Abstract]
Common stock sold	3,661
Common stock, par value	$ 0.001		$ 0.001	$ 0.001
Common stock, price per share	$ 19.25
Proceeds from issuance of common stock	$ 65,830	$ 65,830

Subsequent Event (Details)

Subsequent Event (Details) - nContact Surgical [Member] - USD ($) shares in Thousands, $ in Thousands	Oct. 13, 2015	Sep. 30, 2015
Subsequent Event [Line Items]
Transaction expenses		$ 526
Subsequent Event [Member]
Subsequent Event [Line Items]
Consideration payment, shares	3,757
Consideration payment, value	$ 7,600
Contingent consideration due date		Dec. 31, 2020
Contingent consideration due date on annual growth rate		Dec. 31, 2019
Subsequent Event [Member] | Maximum [Member]
Subsequent Event [Line Items]
Contingent consideration	$ 50,000
Subsequent Event [Member] | Minimum [Member]
Subsequent Event [Line Items]
Sales-based contingent consideration on revenue of annual growth rate	25.00%