AtriCure (ATRC) 10-Q 28 Apr 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 26, 2021
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	000-51470
Entity Registrant Name	AtriCure, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	34-1940305
Entity Address, Address Line One	7555 Innovation Way
Entity Address, City or Town	Mason
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45040
City Area Code	513
Local Phone Number	755-4100
Title of 12(b) Security	Common Stock, $.001 par value
Trading Symbol	ATRC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		45,629,462
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Central Index Key	0001323885

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 85,380	$ 41,944
Short-term investments	141,825	202,274
Accounts receivable, less allowance for credit losses of $1,096 and $1,096	29,741	23,146
Inventories	36,144	35,026
Prepaid and other current assets	5,214	4,347
Total current assets	298,304	306,737
Property and equipment, net	27,633	28,290
Operating lease right-of-use assets	1,622	1,914
Long-term investments	9,127	14,178
Intangible assets, net	127,961	128,199
Goodwill	234,781	234,781
Other noncurrent assets	474	440
Total Assets	699,902	714,539
Current liabilities:
Accounts payable	15,459	12,736
Accrued liabilities	29,696	27,984
Other current liabilities and current maturities of debt and leases	13,308	8,417
Total current liabilities	58,463	49,137
Long-term debt	48,552	53,435
Finance lease liabilities	10,749	10,969
Operating lease liabilities	966	1,180
Contingent consideration and other noncurrent liabilities	189,929	187,424
Total Liabilities	308,659	302,145
Commitments and contingencies (Note 7)
Stockholders' Equity:
Common stock, $0.001 par value, 90,000 shares authorized and 45,623 and 45,346 issued and outstanding	46	45
Additional paid-in capital	738,484	742,389
Accumulated other comprehensive (loss) income	(18)	312
Accumulated deficit	(347,269)	(330,352)
Total Stockholders' Equity	391,243	412,394
Total Liabilities and Stockholders' Equity	$ 699,902	$ 714,539

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for credit losses	$ 1,096	$ 1,096
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	45,623,000	45,346,000
Common stock, shares outstanding	45,623,000	45,346,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Operations and Comprehensive Loss [Abstract]
Revenue	$ 59,275	$ 53,225
Cost of revenue	14,735	14,341
Gross profit	44,540	38,884
Operating expenses:
Research and development expenses	11,217	11,587
Selling, general and administrative expenses	49,208	42,751
Total operating expenses	60,425	54,338
Loss from operations	(15,885)	(15,454)
Other income (expense):
Interest expense	(1,189)	(1,228)
Interest income	134	405
Other	54	(123)
Loss before income tax expense	(16,886)	(16,400)
Income tax expense	31	8
Net loss	$ (16,917)	$ (16,408)
Basic and diluted net loss per share	$ (0.38)	$ (0.42)
Weighted average shares outstanding — basic and diluted	44,632	38,671
Comprehensive loss:
Unrealized loss on investments	$ (31)	$ (63)
Foreign currency translation adjustment	(299)	(150)
Other comprehensive loss	(330)	(213)
Net loss	(16,917)	(16,408)
Comprehensive loss, net of tax	$ (17,247)	$ (16,621)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Beginning Balance at Dec. 31, 2019	$ 40	$ 529,658	$ (282,197)	$ (158)	$ 247,343
Beginning Balance, Shares at Dec. 31, 2019	39,655
Impact of equity compensation plans		(3,356)			(3,356)
Impact of equity compensation plans, Shares	422
Other comprehensive loss				(213)	(213)
Net loss			(16,408)		(16,408)
Ending Balance at Mar. 31, 2020	$ 40	526,302	(298,605)	(371)	227,366
Ending Balance, Shares at Mar. 31, 2020	40,077
Beginning Balance at Dec. 31, 2020	$ 45	742,389	(330,352)	312	412,394
Beginning Balance, Shares at Dec. 31, 2020	45,346
Impact of equity compensation plans	$ 1	(3,905)			(3,904)
Impact of equity compensation plans, Shares	277
Other comprehensive loss				(330)	(330)
Net loss			(16,917)		(16,917)
Ending Balance at Mar. 31, 2021	$ 46	$ 738,484	$ (347,269)	$ (18)	$ 391,243
Ending Balance, Shares at Mar. 31, 2021	45,623

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (16,917)	$ (16,408)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	6,604	4,384
Depreciation	1,884	1,955
Amortization of intangible assets	238	489
Amortization of deferred financing costs	124	141
Loss on disposal of property and equipment	17	32
Amortization (accretion) of investments	555	(3)
Change in value of contingent consideration	2,500	2,458
Other non-cash adjustments to income	254	360
Changes in operating assets and liabilities
Accounts receivable	(6,696)	5,875
Inventories	(1,264)	(2,728)
Other current assets	(891)	(499)
Accounts payable	2,835	2,522
Accrued liabilities	1,799	(14,545)
Other noncurrent assets and liabilities	(358)	(120)
Net cash used in operating activities	(9,316)	(16,087)
Cash flows from investing activities:
Sales and maturities of available-for-sale securities	64,913	19,163
Purchases of property and equipment	(1,326)	(1,832)
Net cash provided by investing activities	63,587	17,331
Cash flows from financing activities:
Payments on debt and leases	(198)	(94)
Proceeds from stock option exercises and employee stock purchase plan	4,588	4,036
Shares repurchased for payment of taxes on stock awards	(15,097)	(11,776)
Net cash used in financing activities	(10,707)	(7,834)
Effect of exchange rate changes on cash and cash equivalents	(128)	(127)
Net increase (decrease) in cash and cash equivalents	43,436	(6,717)
Cash and cash equivalents-beginning of period	41,944	28,483
Cash and cash equivalents-end of period	85,380	21,766
Supplemental cash flow information:
Cash paid for interest	1,066	1,101
Cash paid for income taxes, net of refunds	47	187
Non-cash investing and financing activities:
Accrued purchases of property and equipment	$ 239	$ 903

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
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 —The “Company” or “AtriCure” consists of AtriCure, Inc. and its wholly-owned subsidiaries. The Company is a leading innovator in treatments for atrial fibrillation (Afib) and left atrial appendage (LAA) management and sells its products to medical centers globally through its 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 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 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 year or for any future period. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC. 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 purchase as cash equivalents. Cash equivalents include demand deposits, money market funds and repurchase agreements on deposit with certain financial institutions. Investments —The Company invests primarily in U.S. government and agency obligations, corporate bonds, commercial paper and asset-backed securities and classifies all investments as available-for-sale. Investments maturing in 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). Gains and losses are recognized using the specific identification method when securities are sold and are included in interest income. Revenue Recognition— The Company recognizes revenue when control of promised goods is transferred to customers in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods. This generally occurs upon shipment of goods to customers. See Note 8 for further discussion on revenue. Sales Returns and Allowances —The Company maintains a provision for potential returns of defective or damaged products and invoice adjustments. The Company adjusts the provision using the expected value method based on historical experience. Increases to the provision reduce revenue, and the provision is included in accrued liabilities. Allowance for Credit Losses on Accounts Receivable —The Company evaluates the expected credit losses of accounts receivable, considering historical credit losses, current customer-specific information and other relevant factors when determining the allowance. An increase to the allowance for credit losses results in a corresponding increase in selling, general and administrative expenses. The Company charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs has not been significant. Inventories —Inventories are stated at the lower of cost or net realizable value 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 use all impact inventory reserves for excess, obsolete and expired products. An increase to inventory reserves results in a corresponding increase in cost of revenue. Inventories are written off against the reserve when they are physically disposed. Inventories consist of the following: March 31, December 31, 2021 2020 Raw materials $ 11,274 $ 11,966 Work in process 2,564 2,424 Finished goods 22,306 20,636 Inventories $ 36,144 $ 35,026 Property and Equipment —Property and equipment is stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of assets. The estimated useful life by major asset category is the following: Estimated Useful Life Generators and related equipment 1 - 3 years Building under finance lease 15 years Computers, software and office equipment 3 years Machinery and equipment 3 - 7 years Furniture and fixtures 3 - 7 years Leasehold improvements 5 - 15 years Equipment under finance leases 3 - 5 years The Company assesses the useful lives of property and equipment at least annually and retires assets no longer in use. Maintenance and repair costs are expensed as incurred. The Company reviews property and equipment for impairment at least annually using its best estimates based on reasonable and supportable assumptions and expected future cash flows. Property and equipment impairments have not been significant. The Company’s radiofrequency (RF) and cryo generators are generally placed with customers that use the Company’s disposable products. The estimated useful lives of generators are based on anticipated usage by customers and may change in future periods with changes in usage or introduction of new technology. Depreciation related to generators and related equipment, which is recorded in cost of revenue, was $ 602 and $ 649 for the three months ended March 31, 2021 and 2020. As of March 31, 2021 and December 31, 2020, the net carrying value of generators and related equipment included in net property and equipment was $ 3,464 and $ 3,410 . Leases —The Company determines if an arrangement is a lease at inception of the contract. The Company applies the short-term lease recognition exemption, recognizing lease payments in profit or loss for leases that have a lease term of 12 months or less at commencement and do not include a purchase option whose exercise is reasonably certain. Operating leases are included in operating lease right-of-use (ROU) assets, other current liabilities and current maturities of debt and leases, and operating lease liabilities. Finance leases are included in property and equipment, other current liabilities and current maturities of debt and leases, and finance lease liabilities. ROU assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are measured and recorded at the commencement date based on the present value of lease payments over the lease term. The operating lease ROU asset excludes lease incentives. The Company uses the implicit rate when readily determinable, however, most of the leases do not provide an implicit rate and therefore, the Company uses the incremental borrowing rate based on the information available at measurement. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. For real estate and equipment leases, the Company accounts for the lease and non-lease components as a single lease component. Additionally, the portfolio approach is applied to effectively account for the operating lease ROU assets and liabilities based on the term of the underlying lease. Lease expense is recognized on a straight-line basis over the lease term. See Note 6 for further discussion. Intangible Assets —Intangible assets with determinable useful lives are amortized on a straight-line basis over the estimated periods benefited. Intangible assets include In Process Research and Development (IPR&D), representing the value of technology acquired in business combinations that has not yet reached technological feasibility. The primary basis for determining technological feasibility is obtaining specific regulatory approvals. IPR&D is accounted for as an indefinite-lived intangible asset until completion or abandonment of the IPR&D project. Upon completion of the development project, IPR&D will be amortized over its estimated useful life. The IPR&D assets represent an estimate of the fair value of the pre-market approval (PMA) that could result from the CONVERGE™ IDE and aMAZE™ IDE clinical trials. If the IPR&D projects are abandoned or regulatory approvals are not obtained, the Company may have a full or partial impairment charge related to the IPR&D, calculated as the excess carrying value of the IPR&D assets over the estimated fair value. The Company reviews intangible assets at least annually for impairment using its best estimates based on reasonable and supportable assumptions and projections. The Company performs impairment testing annually on October 1 or more often if impairment indicators are present. Goodwill— Goodwill represents the excess of purchase price over the fair value of the net assets acquired in business combinations. The Company’s goodwill is accounted for in a single reporting unit representing the Company as a whole. The Company performs impairment testing annually on October 1 or more often if impairment indicators are present. Contingent Consideration and Other Noncurrent Liabilities— This balance consists of contingent consideration from business combinations, as well as deferred payroll taxes as a result of the Coronavirus Aid, Relief, and Economic Security Act (CARES Act), asset retirement obligations and other contractual obligations. The contingent consideration balance is included in noncurrent liabilities as settlement is expected to be made primarily in shares of the Company’s common stock pursuant to the SentreHEART, Inc. (SentreHEART) merger agreement. Other Income (Expense) — Other income (expense) consists primarily of foreign currency transaction gains and losses generated by settlements of intercompany balances denominated in Euros and customer invoices transacted in British Pounds. Taxes —Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred income 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 income 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 income tax assets requires significant estimates and judgments about future operating results. Deferred income tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more-likely-than-not that the deferred income tax asset will not be realized. Significant weight is given to evidence that can be objectively verified. The Company evaluates deferred income tax assets on an annual basis to determine if valuation allowances are required. Deferred income 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 income tax assets are future taxable income, future reversals of existing taxable temporary differences, carryforwards and tax planning strategies that are both prudent and feasible. In evaluating the need for a valuation allowance, the existence of cumulative losses in recent years is significant 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 substantially all net deferred income tax assets as it is more-likely-than-not that the benefit of the deferred income tax assets will not be recognized in future periods. The Company has not reclassified income tax effects of the Tax Cuts and Jobs Act within accumulated other comprehensive income (loss) to retained earnings due to its full valuation allowance. Net Loss Per Share —Basic and diluted net loss per share is computed 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 1,955 and 2,889 stock options, restricted stock shares, restricted stock units and performance award shares as of March 31, 2021 and 2020 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 Income (Loss) —In addition to net losses, the comprehensive loss includes foreign currency translation adjustments and unrealized gains (losses) on investments. Accumulated other comprehensive income (loss) consisted of the following, net of tax: Three Months Ended March 31, 2021 2020 Total accumulated other comprehensive income (loss) at beginning of period $ 312 $ ( 158 ) Unrealized Gains (Losses) on Investments Balance at beginning of period $ 54 $ 100 Other comprehensive loss before reclassifications ( 31 ) ( 82 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) — 19 Balance at end of period $ 23 $ 37 Foreign Currency Translation Adjustment Balance at beginning of period $ 258 $ ( 258 ) Other comprehensive loss before reclassifications ( 298 ) ( 222 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) ( 1 ) 72 Balance at end of period $ ( 41 ) $ ( 408 ) Total accumulated other comprehensive loss at end of period $ ( 18 ) $ ( 371 ) Research and Development Costs —Research and development costs are expensed as incurred. These costs include compensation and other internal and external costs associated with the development of and research related to new and existing products or concepts, preclinical studies, clinical trials and related regulatory activities. Advertising Costs — The Company expenses advertising costs as incurred. Advertising costs were not significant during the three months ended March 31, 2021 and 2020. Share-Based Compensation —The Company records share-based compensation for all share-based payment awards, including stock options, restricted stock awards, restricted stock units, performance shares (PSAs) and stock purchases related to an employee stock purchase plan, based on estimated fair values. The value of the portion of an award that is ultimately expected to vest, net of estimated forfeitures, is recognized as expense over the service period. The Company estimates forfeitures at the time of grant and revises them, as necessary, in subsequent periods as actual forfeitures differ from those estimates. The Company recognized share-based compensation expense of $ 6,604 and $ 4,384 for the three months ended March 31, 2021 and 2020. 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 the fair value is affected by the Company’s stock price, as well as assumptions regarding several 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 Company estimates the fair value of restricted stock awards and restricted stock units based upon the grant date closing market price of the Company’s common stock. The Company estimates the fair value of PSAs with a performance condition based on the closing stock price on the date of grant assuming the performance goal will be achieved and may adjust expense over the performance period based on changes to estimates of performance target achievement. If such goals are not met or service is not rendered for the requisite service period, no compensation cost is recognized, and any recognized compensation cost will be reversed. For PSAs with a market condition, a Monte Carlo simulation is performed to estimate the fair value on the date of grant, and compensation cost is recognized over the requisite service period as the employee renders service, even if the market condition is not satisfied. The Company’s determination of the fair value is affected by the Company and peer group’s stock price at the beginning of the service period and grant date, the expected volatility of the Company and peer group’s stock price over the performance period and the correlation coefficient of the daily returns for the Company and peer group over the performance period. The Company also has an employee stock purchase plan (ESPP) which is available to all eligible employees as defined by the plan document. 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 ESPP at the beginning of each purchase period based upon the fair value of the stock at the beginning of the purchase period using the Black-Scholes model and records estimated compensation expense during the purchase period. Expense is adjusted at the time of stock purchase. 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, including intangible assets, 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. Estimates are based on historical experience, where applicable, and other assumptions believed to be reasonable by management. Actual results could differ from those estimates.

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2021
Fair Value [Abstract]
Fair Value	2. FAIR VALUE The Financial Accounting Standards Board’s (FASB) Accounting Standards Codification (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 fair value hierarchy is 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:  Level 1—Quoted prices in active markets for identical assets or liabilities.  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.  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. The Company classifies cash and investments in U.S. government and agency obligations, accounts receivable, short-term other assets, accounts payable and accrued liabilities as Level 1 within the fair value hierarchy. The carrying amounts of these assets and liabilities approximate their fair value due to their relatively short-term nature. Cash equivalents and investments in corporate bonds, commercial paper and asset-backed securities are classified as Level 2 within the fair value hierarchy. The fair value of fixed term debt is estimated by calculating the net present value of future debt payments at current market interest rates and is classified as Level 2. The book value of the Company’s fixed term debt approximates its fair value because the interest rate varies with market rates. 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 March 31, 2021: 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 $ — $ 82,497 $ — $ 82,497 Commercial paper — 48,466 — 48,466 U.S. government and agency obligations 45,205 — — 45,205 Corporate bonds — 48,422 — 48,422 Asset-backed securities — 8,859 — 8,859 Total assets $ 45,205 $ 188,244 $ — $ 233,449 Liabilities: Contingent consideration — — 187,300 187,300 Total liabilities $ — $ — $ 187,300 $ 187,300 There were no changes in the levels or methodology of measurement of financial assets and liabilities during the three months ended March 31, 2021. 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, 2020: 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 $ — $ 38,452 $ — $ 38,452 Commercial paper — 76,914 — 76,914 U.S. government and agency obligations 45,399 — — 45,399 Corporate bonds — 73,730 — 73,730 Asset-backed securities — 20,409 — 20,409 Total assets $ 45,399 $ 209,505 $ — $ 254,904 Liabilities: Contingent consideration $ — $ — $ 184,800 $ 184,800 Total liabilities $ — $ — $ 184,800 $ 184,800 Contingent Consideration. The Company has contingent consideration arrangements arising from the SentreHEART acquisition that obligate the Company to pay certain defined amounts to former shareholders of SentreHEART if specified milestones are met related to the aMAZE IDE clinical trial, including PMA approval and reimbursement for the therapy involving SentreHEART’s devices. As of December 31, 2020, the terms of the contingent consideration arrangements under the nContact merger agreement expired. The Company measures contingent consideration liabilities using unobservable inputs by applying the probability-weighted scenario method, an income approach. Various key assumptions, such as the probability and timing of achievement of the agreed milestones, are used in the determination of fair value of contingent consideration arrangements and are not observable in the market, thus representing a Level 3 measurement within the fair value hierarchy. The recurring Level 3 fair value measurements of the contingent consideration liabilities include the following significant inputs as of March 31, 2021: Weighted average Fair Value Valuation Technique Input Range by relative fair value Probability of payment 70.00 - 85.00 % 80.62 % Regulatory & Reimbursement milestones $ 187,300 Probability-weighted scenario approach Projected year of payment 2022 - 2025 n/a Discount rate 5.56 % 5.56 % Contingent consideration liabilities are periodically measured, with changes in the estimated fair value reflected in selling, general and administrative expenses. Changes in the discount rate, time until payment and probability of payment may result in materially different fair value measurements. A decrease in the discount rate would result in a higher fair value measurement, while a decrease in the probability of payment would result in a lower fair value measurement. Movement in the forecasted timing of achievement to later in the milestone periods would cause a decrease in the fair value measurement. The fair value of the SentreHEART contingent consideration was remeasured as of March 31, 2021 resulting in an increase in fair value due to accretion. The following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for acquisition-related contingent consideration: Three Months Ended Twelve Months Ended March 31, 2021 December 31, 2020 Beginning Balance $ 184,800 $ 185,157 Amounts acquired — — Changes in fair value included in earnings 2,500 ( 357 ) Ending Balance $ 187,300 $ 184,800

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2021
Intangible Assets [Abstract]
Intangible Assets	3. INTANGIBLE ASSETS The following table provides a summary of the Company’s intangible assets: March 31, 2021 December 31, 2020 Estimated Useful Life Cost Accumulated Amortization Cost Accumulated Amortization Technology 5 - 15 years $ 11,691 $ 10,051 $ 11,691 $ 9,813 IPR&D 126,321 — 126,321 — Total $ 138,012 $ 10,051 $ 138,012 $ 9,813 Amortization expense of intangible assets with definite lives, which excludes the IPR&D assets, was $ 238 and $ 489 for the three months ended March 31, 2021 and 2020. Future amortization expense is projected as follows: 2021 (excluding the three months ended March 31, 2021) $ 713 2022 718 2023 18 2024 18 2025 18 2026 and thereafter 155 Total $ 1,640

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2021
Accrued Liabilities [Abstract]
Accrued Liabilities	4. ACCRUED LIABILITIES Accrued liabilities consisted of the following: March 31, December 31, 2021 2020 Accrued payroll and employee-related expenses $ 9,888 $ 8,576 Accrued commissions 7,524 4,765 Accrued legal settlement 4,831 6,000 Accrued bonus 3,034 4,389 Sales returns and allowances 1,993 1,889 Accrued taxes and value-added taxes payable 1,329 1,256 Accrued royalties 713 703 Other accrued liabilities 384 406 Total $ 29,696 $ 27,984

Indebtedness

Indebtedness	3 Months Ended
	Mar. 31, 2021
Indebtedness [Abstract]
Indebtedness	5. INDEBTEDNESS Credit Facility. The Company has a Loan and Security Agreement (Loan Agreement) with Silicon Valley Bank (SVB), which includes a $ 60,000 term loan and a $ 20,000 revolving line of credit. The total combined term loan and revolving line of credit outstanding under the Loan Agreement cannot exceed $ 70,000 at any time prior to SVB’s consent. The term loan and revolving credit facility both mature or expire, as applicable, on August 1, 2024 . On February 8, 2021, the Company and SVB entered into an amendment to the Loan Agreement which modified conditions which allow the Company to defer the term loan principal payments an additional six months , commencing in September 2021. Additionally, the covenant reporting requirements were modified. The amendment was treated as a debt modification. Term loan principal payments commence September 1, 2021. The term loan accrues interest at the greater of the Prime Rate or 5.00 %, plus 0.75 % and is subject to an additional 3.00 % fee on the $ 60,000 term loan principal payable at maturity or upon acceleration or prepayment of the term loan. The Company is accruing the 3.00 % fee over the term of the Loan Agreement, with $ 585 accrued in the outstanding loan balance as of March 31, 2021. Additionally, the unamortized original financing costs related to the term loan of $ 366 are netted against the outstanding loan balance in the Consolidated Balance Sheets and are amortized ratably over the term of the Loan Agreement. The revolving line of credit is subject to an annual facility fee of 0.15 % of the revolving line of credit, and any borrowings thereunder bear interest at the greater of the Prime Rate or 5.00 %. Borrowing availability under the revolving credit facility is based on the lesser of $ 20,000 or a borrowing base calculation as defined by the Loan Agreement. As of March 31, 2021, the Company had no borrowings under the revolving credit facility and had borrowing availability of $ 8,750 . Financing costs related to the revolving line of credit are included in other assets in the Consolidated Balance Sheets and amortized ratably over the twelve-month period of the annual fee. The Loan Agreement also provides for certain prepayment and early termination fees, as well as establishes a minimum liquidity covenant and dividend restrictions, along with other customary terms and conditions. Specified assets have been pledged as collateral. Future maturities of long-term debt are projected as follows: 2021 (excluding the three months ended March 31, 2021) $ 6,667 2022 20,000 2023 20,000 2024 13,333 Total long-term debt, of which $ 11,667 is current and $ 48,333 is noncurrent $ 60,000

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	6. LEASES The Company has operating and finance leases for offices, manufacturing and warehouse facilities and computer equipment. The Company’s leases have remaining lease terms of one year to ten years . Options to renew or extend leases beyond their initial term have been excluded from measurement of the ROU assets and lease liabilities for the majority of leases as exercise is not reasonably certain. The weighted average remaining lease term and the discount rate for the reporting periods is as follows: March 31, 2021 December 31, 2020 Operating Leases Weighted average remaining lease term (years) 3.3 3.2 Weighted average discount rate 5.69 % 5.68 % Finance leases Weighted average remaining lease term (years) 9.4 9.7 Weighted average discount rate 6.91 % 6.91 % In connection with the terms of the Company’s corporate headquarters lease, a letter of credit for $ 1,250 was issued to the building lessor in October 2015. The letter of credit is renewed annually and remains outstanding as of March 31, 2021. The components of lease expense are as follows: Three Months Ended March 31, 2021 2020 Operating lease cost $ 279 $ 349 Finance lease cost: Amortization of right-of-use assets 256 263 Interest on lease liabilities 203 216 Total finance lease cost $ 459 $ 479 Short term lease expense was not significant for the three months ended March 31, 2021 and 2020. Supplemental cash flow information related to leases was as follows: Three Months Ended Three Months Ended March 31, 2021 March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 331 $ 372 Operating cash flows from finance leases 203 216 Financing cash flows from finance leases 198 94 Supplemental balance sheet information related to leases was as follows: March 31, 2021 December 31, 2020 Operating Leases Operating lease right-of-use assets $ 1,622 $ 1,914 Other current liabilities and current maturities of debt and leases 796 927 Operating lease liabilities 966 1,180 Total operating lease liabilities $ 1,762 2,107 Finance Leases Property and equipment, at cost $ 14,650 14,659 Accumulated depreciation ( 5,396 ) ( 5,247 ) Property and equipment, net $ 9,254 9,412 Other current liabilities and current maturities of debt and leases $ 845 823 Finance lease liabilities 10,749 10,969 Total finance lease liabilities $ 11,594 11,792 Maturities of lease liabilities as of March 31, 2021 were as follows: Operating Leases Finance Leases 2021 (excluding the three months ended March 31, 2021) $ 596 $ 1,206 2022 637 1,629 2023 239 1,652 2024 246 1,675 2025 253 1,625 2026 and thereafter — 8,173 Total payments $ 1,971 $ 15,960 Less imputed interest ( 209 ) ( 4,366 ) Total $ 1,762 $ 11,594

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies [Abstract]
Commitments and Contingencies	7. COMMITMENTS AND CONTINGENCIES Royalty Agreements. The Company has royalty agreements in place with terms that include payment of royalties of 3 % to 5 % of specified product sales. One royalty agreement remains in effect through 2025, while the other agreement remains in effect the later of 2023 or until expiration of the underlying patents or patent applications. Parties to the royalty agreements have the right at any time to terminate the agreement immediately for cause. Royalty expense of $ 722 and $ 677 was recorded for the three months ended March 31, 2021 and 2020. Purchase Agreements. The Company enters into standard purchase agreements with certain vendors in the ordinary course of business, generally with terms that allow cancellation. Legal. The Company may, from time to time, become a party to legal proceedings. Such matters are subject to many uncertainties and to outcomes of which the financial impacts are not predictable with assurance and that may not be known for extended periods of time. When management has assessed that a loss is probable and an amount can be reasonably estimated, the Company records a liability. The Company received a Civil Investigative Demand (CID) from the U.S. Department of Justice (USDOJ) in December 2017 stating that it is investigating the Company to determine whether the Company has violated the False Claims Act, relating to the promotion of certain medical devices related to the treatment of atrial fibrillation for off-label use and submitted or caused to be submitted false claims to certain federal and state health care programs for medically unnecessary healthcare services related to the treatment of atrial fibrillation. The CID covers the period from January 2010 to December 2017 and required the production of documents and answers to written interrogatories. The Company had no knowledge of the investigation prior to receipt of the CID. The Company maintains rigorous policies and procedures to promote compliance with the False Claims Act and other applicable regulatory requirements. The Company provided the USDOJ with documents and answers to the written interrogatories. In March 2021, USDOJ informed the Company that its investigation was based on a lawsuit brought under federal and state False Claims Acts, and that the United States and the various states named in the lawsuit were electing not to intervene in the case. USDOJ subsequently filed a Notice of Election to Decline Intervention and to Unseal Complaint, and the case was unsealed. It is not possible to predict when this matter may be resolved or what impact, if any, the outcome of this matter might have on our consolidated financial position, results of operations, or cash flows. The Company acquired nContact Surgical, Inc. pursuant to a merger agreement dated October 4, 2015. The merger agreement provides for contingent consideration or “earnout” to be paid upon attaining specified regulatory approvals and clinical and revenue milestones. The merger agreement’s earnout provisions required the Company to deliver periodic earnout reports to a designated representative of former nContact stockholders. In response to the reports delivered in and after February 2018, the Company received letters from representatives purporting to serve as “earnout objection statements” (as that term is defined in the merger agreement) and claim that for purposes of determining the commercial milestone payment, the Company should be including revenues of certain additional items and products that the Company has not included in its earnout statements. During February 2021, the Company entered into a settlement agreement with the former nContact stockholders requiring payment of $ 6,000 . The Company recorded the $ 6,000 settlement as a component of current liabilities as of December 31, 2020 as the underlying cause occurred prior to December 31, 2020.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2021
Revenue [Abstract]
Revenue	8. REVENUE Revenue is generated primarily from the sale of medical devices. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those devices when control of promised devices is transferred to customers. At contract inception, the Company assesses the products promised in its contracts with customers and identifies a performance obligation for each promise to transfer to the customer a product that is distinct. The Company’s devices are distinct and represent performance obligations. These performance obligations are satisfied, and revenue is recognized at a point in time upon shipment or delivery of products. Sales of devices are categorized as follows: open ablation, minimally invasive ablation, appendage management and valve tools. Shipping and handling activities performed after control over products transfers to customers are considered activities to fulfill the promise to transfer the products rather than as separate promises to customers. Products are sold primarily through a direct sales force and through distributors in certain international markets. 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, with some exceptions. The Company does not maintain any post-shipping obligations to customers. No installation, calibration or testing of products is performed by the Company subsequent to shipment in order to render products operational. Significant judgments and estimates involved in the Company’s recognition of revenue include the estimation of a provision for returns. The Company estimates the provision for sales returns and allowances using the expected value method based on historical experience and other factors that we believe could impact our expected returns, including defective or damaged products and invoice adjustments. In the normal course of business, the Company generally does not accept product returns unless a product is defective as manufactured. The Company does not provide customers with the right to a refund. The Company expects to be entitled to the total consideration for the products ordered by customers as product pricing is fixed according to the terms of customer contracts and payment terms are short. Payment terms fall within the one-year guidance for the practical expedient which allows the Company to forgo adjustment of the promised amount of consideration for the effects of a significant financing component. The Company excludes taxes assessed by governmental authorities on revenue-producing transactions from the measurement of the transaction price. Costs associated with product sales include commissions and royalties. Considering that product sales are performance obligations in contracts that are satisfied at a point in time, commission expense associated with product sales and royalties paid based on sales of certain products is incurred at that point in time rather than over time. Therefore, the Company applies the practical expedient and recognizes commissions and royalties as expense when incurred because the expense is incurred at a point in time and the amortization period is less than one year. Commissions are recorded as selling expense and royalties are recorded as cost of revenue. See Note 11 for disaggregated revenue by geographic area and by product category.

Income Tax Provision

Income Tax Provision	3 Months Ended
	Mar. 31, 2021
Income Tax Provision [Abstract]
Income Tax Provision	9. INCOME TAX PROVISION The Company files federal, state, and foreign income tax returns in jurisdictions with varying statutes of limitations. The Company uses the asset and liability method to determine its provision for income taxes. The Company’s provision for income taxes in interim periods is computed by applying the discrete method and is based on financial results through the end of the interim period. The Company determined that using the discrete method is more appropriate than using the annual effective tax rate method. The Company is unable to estimate the annual effective tax rate with sufficient precision to use the effective tax rate method, which requires a full-year projection of income. The effective tax rate for the three months ended March 31, 2021 and 2020 was ( 0.18 %) and ( 0.05 %). The Company’s worldwide effective tax rate differs from the US statutory rate of 21 % primarily due to the Company’s valuation allowance in the United States and Netherlands. Federal, state and local returns of the Company are routinely subject to review by various taxing authorities. The Company has not accrued any interest and penalties related to unrecognized income tax benefits as a result of offsetting of net operating losses. However, if the situation occurs, the Company will recognize interest and penalties within income tax expense and within the related tax liability.

Equity Compensation Plans

Equity Compensation Plans	3 Months Ended
	Mar. 31, 2021
Equity Compensation Plans [Abstract]
Equity Compensation Plans	10. EQUITY COMPENSATION PLANS The Company has two share-based incentive plans: the 2014 Stock Incentive Plan (2014 Plan) and the 2018 Employee Stock Purchase Plan (ESPP). Stock Incentive Plan Under the 2014 Plan, the Board of Directors may grant incentive stock options to Company employees and may grant restricted stock awards or restricted stock units (collectively RSAs), nonstatutory stock options, performance share awards (PSAs) or stock appreciation rights to Company employees, directors and consultants. The administrator (the Compensation Committee of the Board of Directors) has the authority 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 March 31, 2021, 12,899 shares of common stock had been reserved for issuance under the 2014 Plan, and 1,586 shares were available for future grants. Stock options, restricted stock awards and restricted stock units granted generally vest at a rate of 33.3 % on the first, second and third anniversaries of the grant date. Stock options generally expire ten years from the date of grant. The award agreements for the PSAs provide that each PSA that vests represents the right to receive one share of the Company’s common stock at the end of the performance period. With respect to the PSAs, the number of shares that vest and are issued to the recipient is based upon the Company’s performance with respect to specified targets at the end of the three year performance period. Payout opportunities range from 0 % to 100 % of the target amount for awards granted prior to 2021, while awards granted in 2021 have payout opportunities ranging from 0 % to 200 % of the target amount. These ranges are used to calculate the number of shares that will be issuable when the award vests. All or a portion of the PSAs may vest following a change of control or a termination of service by reason of death or disability. PSAs granted prior to 2021 have performance targets based on the Company’s revenue compound annual growth rate (CAGR). PSAs granted in 2021 have two equally weighted performance targets measured at the end of the three year performance period: (i) the Company’s revenue CAGR; and (ii) relative total shareholder return (TSR). TSR is measured against the Nasdaq Health Care Index constituents and the 20 -trading-day average stock price prior to the end of the performance period over the 20 -trading-day average stock price prior to the beginning of the performance period. The performance and market condition payouts will be determined independently and accumulated to determine the total payout for the three year performance period, subject to the maximum(s) defined in the PSA agreements. Employee Stock Purchase Plan The ESPP is available to eligible employees as defined in the plan document. Under the ESPP, shares of the Company’s common stock may be purchased at a discount ( 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 a value of more than $ 25 of the Company’s common stock in a calendar year and may not purchase a value of more than 3 shares during an offering period. As of March 31, 2021, there were 387 shares available for future issuance under the ESPP. Expense Information Under FASB ASC 718 The following table summarizes the allocation of share-based compensation expense: Three Months Ended March 31, 2021 2020 Cost of revenue $ 419 $ 287 Research and development expenses 937 655 Selling, general and administrative expenses 5,248 3,442 Total $ 6,604 $ 4,384

Segment and Geographic Informat

Segment and Geographic Information	3 Months Ended
	Mar. 31, 2021
Segment and Geographic Information [Abstract]
Segment and Geographic Information	11. SEGMENT AND GEOGRAPHIC INFORMATION 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 globally. Management considers all such sales to be part of a single operating segment. Revenue attributed to geographic areas, based on the location of customers to whom products are sold, is as follows: Three Months Ended March 31, 2021 2020 United States $ 50,309 $ 43,473 Europe 5,766 5,945 Asia 2,873 3,537 Other international 327 270 Total international 8,966 9,752 Total revenue $ 59,275 $ 53,225 United States revenue by product type is as follows: Three Months Ended March 31, 2021 2020 Open ablation $ 21,075 $ 19,218 Minimally invasive ablation 8,385 6,561 Appendage management 20,587 17,419 Total ablation and appendage management 50,047 43,198 Valve tools 262 275 Total United States $ 50,309 $ 43,473 International revenue by product type is as follows: Three Months Ended March 31, 2021 2020 Open ablation $ 4,417 $ 5,115 Minimally invasive ablation 1,274 1,545 Appendage management 3,258 3,062 Total ablation and appendage management 8,949 9,722 Valve tools 17 30 Total international $ 8,966 $ 9,752 The Company’s long-lived assets are located primarily in the United States, except for $ 1,510 as of March 31, 2021 and $ 1,693 as of December 31, 2020, which are located primarily in Europe.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2021
Description of Business and Summary of Significant Accounting Policies [Abstract]
Nature of the Business	Nature of the Business —The “Company” or “AtriCure” consists of AtriCure, Inc. and its wholly-owned subsidiaries. The Company is a leading innovator in treatments for atrial fibrillation (Afib) and left atrial appendage (LAA) management and sells its products to medical centers globally through its 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 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 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 year or for any future period. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC. 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 purchase as cash equivalents. Cash equivalents include demand deposits, money market funds and repurchase agreements on deposit with certain financial institutions.
Investments	Investments —The Company invests primarily in U.S. government and agency obligations, corporate bonds, commercial paper and asset-backed securities and classifies all investments as available-for-sale. Investments maturing in 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). Gains and losses are recognized using the specific identification method when securities are sold and are included in interest income.
Revenue Recognition	Revenue Recognition— The Company recognizes revenue when control of promised goods is transferred to customers in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods. This generally occurs upon shipment of goods to customers. See Note 8 for further discussion on revenue.
Sales Returns and Allowances	Sales Returns and Allowances —The Company maintains a provision for potential returns of defective or damaged products and invoice adjustments. The Company adjusts the provision using the expected value method based on historical experience. Increases to the provision reduce revenue, and the provision is included in accrued liabilities.
Allowance for Credit Losses on Accounts Receivable	Allowance for Credit Losses on Accounts Receivable —The Company evaluates the expected credit losses of accounts receivable, considering historical credit losses, current customer-specific information and other relevant factors when determining the allowance. An increase to the allowance for credit losses results in a corresponding increase in selling, general and administrative expenses. The Company charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs has not been significant.
Inventories	Inventories —Inventories are stated at the lower of cost or net realizable value 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 use all impact inventory reserves for excess, obsolete and expired products. An increase to inventory reserves results in a corresponding increase in cost of revenue. Inventories are written off against the reserve when they are physically disposed. Inventories consist of the following: March 31, December 31, 2021 2020 Raw materials $ 11,274 $ 11,966 Work in process 2,564 2,424 Finished goods 22,306 20,636 Inventories $ 36,144 $ 35,026
Property and Equipment	Property and Equipment —Property and equipment is stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of assets. The estimated useful life by major asset category is the following: Estimated Useful Life Generators and related equipment 1 - 3 years Building under finance lease 15 years Computers, software and office equipment 3 years Machinery and equipment 3 - 7 years Furniture and fixtures 3 - 7 years Leasehold improvements 5 - 15 years Equipment under finance leases 3 - 5 years The Company assesses the useful lives of property and equipment at least annually and retires assets no longer in use. Maintenance and repair costs are expensed as incurred. The Company reviews property and equipment for impairment at least annually using its best estimates based on reasonable and supportable assumptions and expected future cash flows. Property and equipment impairments have not been significant. The Company’s radiofrequency (RF) and cryo generators are generally placed with customers that use the Company’s disposable products. The estimated useful lives of generators are based on anticipated usage by customers and may change in future periods with changes in usage or introduction of new technology. Depreciation related to generators and related equipment, which is recorded in cost of revenue, was $ 602 and $ 649 for the three months ended March 31, 2021 and 2020. As of March 31, 2021 and December 31, 2020, the net carrying value of generators and related equipment included in net property and equipment was $ 3,464 and $ 3,410 .
Leases	Leases —The Company determines if an arrangement is a lease at inception of the contract. The Company applies the short-term lease recognition exemption, recognizing lease payments in profit or loss for leases that have a lease term of 12 months or less at commencement and do not include a purchase option whose exercise is reasonably certain. Operating leases are included in operating lease right-of-use (ROU) assets, other current liabilities and current maturities of debt and leases, and operating lease liabilities. Finance leases are included in property and equipment, other current liabilities and current maturities of debt and leases, and finance lease liabilities. ROU assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are measured and recorded at the commencement date based on the present value of lease payments over the lease term. The operating lease ROU asset excludes lease incentives. The Company uses the implicit rate when readily determinable, however, most of the leases do not provide an implicit rate and therefore, the Company uses the incremental borrowing rate based on the information available at measurement. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. For real estate and equipment leases, the Company accounts for the lease and non-lease components as a single lease component. Additionally, the portfolio approach is applied to effectively account for the operating lease ROU assets and liabilities based on the term of the underlying lease. Lease expense is recognized on a straight-line basis over the lease term. See Note 6 for further discussion.
Intangible Assets	Intangible Assets —Intangible assets with determinable useful lives are amortized on a straight-line basis over the estimated periods benefited. Intangible assets include In Process Research and Development (IPR&D), representing the value of technology acquired in business combinations that has not yet reached technological feasibility. The primary basis for determining technological feasibility is obtaining specific regulatory approvals. IPR&D is accounted for as an indefinite-lived intangible asset until completion or abandonment of the IPR&D project. Upon completion of the development project, IPR&D will be amortized over its estimated useful life. The IPR&D assets represent an estimate of the fair value of the pre-market approval (PMA) that could result from the CONVERGE™ IDE and aMAZE™ IDE clinical trials. If the IPR&D projects are abandoned or regulatory approvals are not obtained, the Company may have a full or partial impairment charge related to the IPR&D, calculated as the excess carrying value of the IPR&D assets over the estimated fair value. The Company reviews intangible assets at least annually for impairment using its best estimates based on reasonable and supportable assumptions and projections. The Company performs impairment testing annually on October 1 or more often if impairment indicators are present.
Goodwill	Goodwill— Goodwill represents the excess of purchase price over the fair value of the net assets acquired in business combinations. The Company’s goodwill is accounted for in a single reporting unit representing the Company as a whole. The Company performs impairment testing annually on October 1 or more often if impairment indicators are present.
Contingent Consideration and Other Noncurrent Liabilities	Contingent Consideration and Other Noncurrent Liabilities— This balance consists of contingent consideration from business combinations, as well as deferred payroll taxes as a result of the Coronavirus Aid, Relief, and Economic Security Act (CARES Act), asset retirement obligations and other contractual obligations. The contingent consideration balance is included in noncurrent liabilities as settlement is expected to be made primarily in shares of the Company’s common stock pursuant to the SentreHEART, Inc. (SentreHEART) merger agreement.
Other Income (Expense)	Other Income (Expense) — Other income (expense) consists primarily of foreign currency transaction gains and losses generated by settlements of intercompany balances denominated in Euros and customer invoices transacted in British Pounds.
Taxes	Taxes —Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred income 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 income 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 income tax assets requires significant estimates and judgments about future operating results. Deferred income tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more-likely-than-not that the deferred income tax asset will not be realized. Significant weight is given to evidence that can be objectively verified. The Company evaluates deferred income tax assets on an annual basis to determine if valuation allowances are required. Deferred income 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 income tax assets are future taxable income, future reversals of existing taxable temporary differences, carryforwards and tax planning strategies that are both prudent and feasible. In evaluating the need for a valuation allowance, the existence of cumulative losses in recent years is significant 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 substantially all net deferred income tax assets as it is more-likely-than-not that the benefit of the deferred income tax assets will not be recognized in future periods. The Company has not reclassified income tax effects of the Tax Cuts and Jobs Act within accumulated other comprehensive income (loss) to retained earnings due to its full valuation allowance.
Net Loss Per Share	Net Loss Per Share —Basic and diluted net loss per share is computed 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 1,955 and 2,889 stock options, restricted stock shares, restricted stock units and performance award shares as of March 31, 2021 and 2020 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 Income (Loss)	Comprehensive Loss and Accumulated Other Comprehensive Income (Loss) —In addition to net losses, the comprehensive loss includes foreign currency translation adjustments and unrealized gains (losses) on investments. Accumulated other comprehensive income (loss) consisted of the following, net of tax: Three Months Ended March 31, 2021 2020 Total accumulated other comprehensive income (loss) at beginning of period $ 312 $ ( 158 ) Unrealized Gains (Losses) on Investments Balance at beginning of period $ 54 $ 100 Other comprehensive loss before reclassifications ( 31 ) ( 82 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) — 19 Balance at end of period $ 23 $ 37 Foreign Currency Translation Adjustment Balance at beginning of period $ 258 $ ( 258 ) Other comprehensive loss before reclassifications ( 298 ) ( 222 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) ( 1 ) 72 Balance at end of period $ ( 41 ) $ ( 408 ) Total accumulated other comprehensive loss at end of period $ ( 18 ) $ ( 371 )
Research and Development Costs	Research and Development Costs —Research and development costs are expensed as incurred. These costs include compensation and other internal and external costs associated with the development of and research related to new and existing products or concepts, preclinical studies, clinical trials and related regulatory activities.
Advertising Costs	Advertising Costs — The Company expenses advertising costs as incurred. Advertising costs were not significant during the three months ended March 31, 2021 and 2020.
Share-Based Compensation	Share-Based Compensation —The Company records share-based compensation for all share-based payment awards, including stock options, restricted stock awards, restricted stock units, performance shares (PSAs) and stock purchases related to an employee stock purchase plan, based on estimated fair values. The value of the portion of an award that is ultimately expected to vest, net of estimated forfeitures, is recognized as expense over the service period. The Company estimates forfeitures at the time of grant and revises them, as necessary, in subsequent periods as actual forfeitures differ from those estimates. The Company recognized share-based compensation expense of $ 6,604 and $ 4,384 for the three months ended March 31, 2021 and 2020. 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 the fair value is affected by the Company’s stock price, as well as assumptions regarding several 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 Company estimates the fair value of restricted stock awards and restricted stock units based upon the grant date closing market price of the Company’s common stock. The Company estimates the fair value of PSAs with a performance condition based on the closing stock price on the date of grant assuming the performance goal will be achieved and may adjust expense over the performance period based on changes to estimates of performance target achievement. If such goals are not met or service is not rendered for the requisite service period, no compensation cost is recognized, and any recognized compensation cost will be reversed. For PSAs with a market condition, a Monte Carlo simulation is performed to estimate the fair value on the date of grant, and compensation cost is recognized over the requisite service period as the employee renders service, even if the market condition is not satisfied. The Company’s determination of the fair value is affected by the Company and peer group’s stock price at the beginning of the service period and grant date, the expected volatility of the Company and peer group’s stock price over the performance period and the correlation coefficient of the daily returns for the Company and peer group over the performance period. The Company also has an employee stock purchase plan (ESPP) which is available to all eligible employees as defined by the plan document. 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 ESPP at the beginning of each purchase period based upon the fair value of the stock at the beginning of the purchase period using the Black-Scholes model and records estimated compensation expense during the purchase period. Expense is adjusted at the time of stock purchase.
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, including intangible assets, 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. Estimates are based on historical experience, where applicable, and other assumptions believed to be reasonable by management. Actual results could differ from those estimates.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Description of Business and Summary of Significant Accounting Policies [Abstract]
Summary Of Inventories	Inventories consist of the following: March 31, December 31, 2021 2020 Raw materials $ 11,274 $ 11,966 Work in process 2,564 2,424 Finished goods 22,306 20,636 Inventories $ 36,144 $ 35,026
Summary Of Property And Equipment	Estimated Useful Life Generators and related equipment 1 - 3 years Building under finance lease 15 years Computers, software and office equipment 3 years Machinery and equipment 3 - 7 years Furniture and fixtures 3 - 7 years Leasehold improvements 5 - 15 years Equipment under finance leases 3 - 5 years
Accumulated Other Comprehensive Income (Loss)	Accumulated other comprehensive income (loss) consisted of the following, net of tax: Three Months Ended March 31, 2021 2020 Total accumulated other comprehensive income (loss) at beginning of period $ 312 $ ( 158 ) Unrealized Gains (Losses) on Investments Balance at beginning of period $ 54 $ 100 Other comprehensive loss before reclassifications ( 31 ) ( 82 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) — 19 Balance at end of period $ 23 $ 37 Foreign Currency Translation Adjustment Balance at beginning of period $ 258 $ ( 258 ) Other comprehensive loss before reclassifications ( 298 ) ( 222 ) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) ( 1 ) 72 Balance at end of period $ ( 41 ) $ ( 408 ) Total accumulated other comprehensive loss at end of period $ ( 18 ) $ ( 371 )

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value [Abstract]
Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis	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 March 31, 2021: 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 $ — $ 82,497 $ — $ 82,497 Commercial paper — 48,466 — 48,466 U.S. government and agency obligations 45,205 — — 45,205 Corporate bonds — 48,422 — 48,422 Asset-backed securities — 8,859 — 8,859 Total assets $ 45,205 $ 188,244 $ — $ 233,449 Liabilities: Contingent consideration — — 187,300 187,300 Total liabilities $ — $ — $ 187,300 $ 187,300 There were no changes in the levels or methodology of measurement of financial assets and liabilities during the three months ended March 31, 2021. 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, 2020: 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 $ — $ 38,452 $ — $ 38,452 Commercial paper — 76,914 — 76,914 U.S. government and agency obligations 45,399 — — 45,399 Corporate bonds — 73,730 — 73,730 Asset-backed securities — 20,409 — 20,409 Total assets $ 45,399 $ 209,505 $ — $ 254,904 Liabilities: Contingent consideration $ — $ — $ 184,800 $ 184,800 Total liabilities $ — $ — $ 184,800 $ 184,800
Level 3 Fair Value Measurements Of Contingent Consideration Liabilities	Weighted average Fair Value Valuation Technique Input Range by relative fair value Probability of payment 70.00 - 85.00 % 80.62 % Regulatory & Reimbursement milestones $ 187,300 Probability-weighted scenario approach Projected year of payment 2022 - 2025 n/a Discount rate 5.56 % 5.56 %
Level 3 Fair Value Measurements For Acquisition-Related Contingent Consideration	The following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for acquisition-related contingent consideration: Three Months Ended Twelve Months Ended March 31, 2021 December 31, 2020 Beginning Balance $ 184,800 $ 185,157 Amounts acquired — — Changes in fair value included in earnings 2,500 ( 357 ) Ending Balance $ 187,300 $ 184,800

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2021
Intangible Assets [Abstract]
Company's Intangible Assets	The following table provides a summary of the Company’s intangible assets: March 31, 2021 December 31, 2020 Estimated Useful Life Cost Accumulated Amortization Cost Accumulated Amortization Technology 5 - 15 years $ 11,691 $ 10,051 $ 11,691 $ 9,813 IPR&D 126,321 — 126,321 — Total $ 138,012 $ 10,051 $ 138,012 $ 9,813
Future Amortization Expense Related To Intangible Assets With Definite Lives	Future amortization expense is projected as follows: 2021 (excluding the three months ended March 31, 2021) $ 713 2022 718 2023 18 2024 18 2025 18 2026 and thereafter 155 Total $ 1,640

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Accrued Liabilities [Abstract]
Accrued Liabilities	Accrued liabilities consisted of the following: March 31, December 31, 2021 2020 Accrued payroll and employee-related expenses $ 9,888 $ 8,576 Accrued commissions 7,524 4,765 Accrued legal settlement 4,831 6,000 Accrued bonus 3,034 4,389 Sales returns and allowances 1,993 1,889 Accrued taxes and value-added taxes payable 1,329 1,256 Accrued royalties 713 703 Other accrued liabilities 384 406 Total $ 29,696 $ 27,984

Indebtedness (Tables)

Indebtedness (Tables)	3 Months Ended
	Mar. 31, 2021
Indebtedness [Abstract]
Future Maturities On Debt	2021 (excluding the three months ended March 31, 2021) $ 6,667 2022 20,000 2023 20,000 2024 13,333 Total long-term debt, of which $ 11,667 is current and $ 48,333 is noncurrent $ 60,000

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Summary Of Weighted Average Remaining Lease Term And Discount Rate	March 31, 2021 December 31, 2020 Operating Leases Weighted average remaining lease term (years) 3.3 3.2 Weighted average discount rate 5.69 % 5.68 % Finance leases Weighted average remaining lease term (years) 9.4 9.7 Weighted average discount rate 6.91 % 6.91 %
Summary Of Components Of Lease Expense	Three Months Ended March 31, 2021 2020 Operating lease cost $ 279 $ 349 Finance lease cost: Amortization of right-of-use assets 256 263 Interest on lease liabilities 203 216 Total finance lease cost $ 459 $ 479
Summary Of Supplemental Cash Flow Information Related To Leases	Three Months Ended Three Months Ended March 31, 2021 March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 331 $ 372 Operating cash flows from finance leases 203 216 Financing cash flows from finance leases 198 94
Summary Of Supplemental Balance Sheet Information Related To Leases	March 31, 2021 December 31, 2020 Operating Leases Operating lease right-of-use assets $ 1,622 $ 1,914 Other current liabilities and current maturities of debt and leases 796 927 Operating lease liabilities 966 1,180 Total operating lease liabilities $ 1,762 2,107 Finance Leases Property and equipment, at cost $ 14,650 14,659 Accumulated depreciation ( 5,396 ) ( 5,247 ) Property and equipment, net $ 9,254 9,412 Other current liabilities and current maturities of debt and leases $ 845 823 Finance lease liabilities 10,749 10,969 Total finance lease liabilities $ 11,594 11,792
Schedule Of Maturities Of Lease Liabilities	Operating Leases Finance Leases 2021 (excluding the three months ended March 31, 2021) $ 596 $ 1,206 2022 637 1,629 2023 239 1,652 2024 246 1,675 2025 253 1,625 2026 and thereafter — 8,173 Total payments $ 1,971 $ 15,960 Less imputed interest ( 209 ) ( 4,366 ) Total $ 1,762 $ 11,594

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2021
Equity Compensation Plans [Abstract]
Share-Based Compensation Expense Related To Employee Share-Based Compensation	The following table summarizes the allocation of share-based compensation expense: Three Months Ended March 31, 2021 2020 Cost of revenue $ 419 $ 287 Research and development expenses 937 655 Selling, general and administrative expenses 5,248 3,442 Total $ 6,604 $ 4,384

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment and Geographic Information [Abstract]
Revenue By Geographic Area	Three Months Ended March 31, 2021 2020 United States $ 50,309 $ 43,473 Europe 5,766 5,945 Asia 2,873 3,537 Other international 327 270 Total international 8,966 9,752 Total revenue $ 59,275 $ 53,225
Revenue By Product Type	United States revenue by product type is as follows: Three Months Ended March 31, 2021 2020 Open ablation $ 21,075 $ 19,218 Minimally invasive ablation 8,385 6,561 Appendage management 20,587 17,419 Total ablation and appendage management 50,047 43,198 Valve tools 262 275 Total United States $ 50,309 $ 43,473 International revenue by product type is as follows: Three Months Ended March 31, 2021 2020 Open ablation $ 4,417 $ 5,115 Minimally invasive ablation 1,274 1,545 Appendage management 3,258 3,062 Total ablation and appendage management 8,949 9,722 Valve tools 17 30 Total international $ 8,966 $ 9,752

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Description Of Business And Significant Accounting Policies [Line Items]
Depreciation	$ 1,884	$ 1,955
Property and equipment, net	$ 27,633		$ 28,290
Options, restricted stock and performance based shares excluded from calculation of net loss per share	1,955	2,889
Share-based compensation expense recognized	$ 6,604	$ 4,384
Generators [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Depreciation	602	$ 649
Generators And Related Equipment [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Property and equipment, net	$ 3,464		$ 3,410
Short-term Debt [Member]
Description Of Business And Significant Accounting Policies [Line Items]
Maturity period of short term investment	1 year

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies (Summary Of Inventories) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Description of Business and Summary of Significant Accounting Policies [Abstract]
Raw materials	$ 11,274	$ 11,966
Work in process	2,564	2,424
Finished goods	22,306	20,636
Inventories	$ 36,144	$ 35,026

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies (Summary Of Property And Equipment) (Details)	3 Months Ended
	Mar. 31, 2021
Building [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Computer and Other Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Generator and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	1 year
Minimum [Member] | Machinery, Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Minimum [Member] | Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum [Member] | Generator and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum [Member] | Machinery, Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Maximum [Member] | Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years

Description of Business and S_7

Description of Business and Summary of Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive (loss) income at beginning of period	$ 312	$ (158)
Total accumulated other comprehensive income (loss) at end of period	(18)	(371)
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive (loss) income at beginning of period	54	100
Other comprehensive income (loss) before reclassifications	(31)	(82)
Amounts reclassified from accumulated other comprehensive (loss) income to other income (expense)		19
Total accumulated other comprehensive income (loss) at end of period	23	37
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive (loss) income at beginning of period	258	(258)
Other comprehensive income (loss) before reclassifications	(298)	(222)
Amounts reclassified from accumulated other comprehensive (loss) income to other income (expense)	(1)	72
Total accumulated other comprehensive income (loss) at end of period	$ (41)	$ (408)

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in value of contingent consideration	$ 2,500	$ 2,458

Fair Value (Financial Assets An

Fair Value (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets:
Total assets	$ 233,449	$ 254,904
Liabilities:
Contingent consideration	187,300	184,800
Total liabilities	187,300	184,800
Money Market Funds [Member]
Assets:
Total assets	82,497	38,452
Commercial Paper [Member]
Assets:
Total assets	48,466	76,914
U.S. Government And Agency Obligations [Member]
Assets:
Total assets	45,205	45,399
Corporate Bonds [Member]
Assets:
Total assets	48,422	73,730
Asset-backed Securities [Member]
Assets:
Total assets	8,859	20,409
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total assets	45,205	45,399
Liabilities:
Contingent consideration
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Government And Agency Obligations [Member]
Assets:
Total assets	45,205	45,399
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total assets	188,244	209,505
Liabilities:
Contingent consideration
Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Assets:
Total assets	82,497	38,452
Significant Other Observable Inputs (Level 2) [Member] | Commercial Paper [Member]
Assets:
Total assets	48,466	76,914
Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Assets:
Total assets	48,422	73,730
Significant Other Observable Inputs (Level 2) [Member] | Asset-backed Securities [Member]
Assets:
Total assets	8,859	20,409
Significant Other Unobservable Inputs (Level 3) [Member]
Liabilities:
Contingent consideration	187,300	184,800
Total liabilities	$ 187,300	$ 184,800

Fair Value (Level 3 Fair Value

Fair Value (Level 3 Fair Value Measurements Of Contingent Consideration Liabilities) (Details) - Significant Other Unobservable Inputs (Level 3) [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Fair Value, Measurements, Recurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Regulatory & Reimbursement milestones	$ 187,300
Fair Value, Measurements, Recurring [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	5.56%
Minimum [Member] | Measurement Input, Year Projection [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Projected fiscal year of payment	2022
Minimum [Member] | Fair Value, Measurements, Recurring [Member] | Measurement Input, Probabilty Of Payment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	70.00%
Maximum [Member] | Fair Value, Measurements, Recurring [Member] | Measurement Input, Probabilty Of Payment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	85.00%
Maximum [Member] | Fair Value, Measurements, Recurring [Member] | Measurement Input, Year Projection [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Projected fiscal year of payment	2025
Weighted Average [Member] | Fair Value, Measurements, Recurring [Member] | Measurement Input, Probabilty Of Payment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	80.62%
Weighted Average [Member] | Fair Value, Measurements, Recurring [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	5.56%

Fair Value (Level 3 Fair Valu_2

Fair Value (Level 3 Fair Value Measurements For Acquisition-Related Contingent Consideration) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair Value [Abstract]
Beginning Balance	$ 184,800	$ 185,157
Amounts acquired
Changes in fair value included in earnings	2,500	(357)
Ending Balance	$ 187,300	$ 184,800

Intangible Assets (Narrative) (

Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 238	$ 489
Minimum [Member] | Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Maximum [Member] | Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	15 years

Intangible Assets (Company's In

Intangible Assets (Company's Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Cost	$ 138,012	$ 138,012
Accumulated Amortization	10,051	9,813
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	11,691	11,691
Accumulated Amortization	10,051	9,813
IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	$ 126,321	$ 126,321
Minimum [Member] | Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Maximum [Member] | Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	15 years

Intangible Assets (Future Amort

Intangible Assets (Future Amortization Expense Related To Intangible Assets With Definite Lives) (Details) $ in Thousands	Mar. 31, 2021USD ($)
Intangible Assets [Abstract]
2021 (excluding the three months ended March 31, 2021)	$ 713
2022	718
2023	18
2024	18
2025	18
2026 and thereafter	155
Total	$ 1,640

Accrued Liabilities (Accrued Li

Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Liabilities [Abstract]
Accrued payroll and employee-related expenses	$ 9,888	$ 8,576
Accrued commissions	7,524	4,765
Accrued legal settlement	4,831	6,000
Accrued bonus	3,034	4,389
Sales returns and allowances	1,993	1,889
Accrued taxes and value-added taxes payable	1,329	1,256
Accrued royalties	713	703
Other accrued liabilities	384	406
Total	$ 29,696	$ 27,984

Indebtedness (Narrative) (Detai

Indebtedness (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Oct. 31, 2015
Line of Credit Facility [Line Items]
Amended loan payment deferral period	6 months
Letter of credit outstanding		$ 1,250,000
Silicon Valley Bank Agreement [Member]
Line of Credit Facility [Line Items]
Totcal combined debt, maximum amount outstanding	$ 70,000,000
Silicon Valley Bank Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	20,000,000
Line of credit, borrowings	$ 0
Maturity date	Aug. 1, 2024
Line of credit, revolving line of credit	$ 8,750,000
Borrowing availability threshold	$ 20,000,000
Annual facility fee	0.15%
Silicon Valley Bank Agreement [Member] | Revolving Credit Facility [Member] | Prime Rate [Member]
Line of Credit Facility [Line Items]
Applicable interest rate	5.00%
Term Loan [Member] | Silicon Valley Bank Agreement [Member]
Line of Credit Facility [Line Items]
Loan amount	$ 60,000,000
Annual commitment fee, percentage	3.00%
Accrued fee amount	$ 585,000
Financing costs	$ 366,000
Term Loan [Member] | Silicon Valley Bank Agreement [Member] | Prime Rate [Member]
Line of Credit Facility [Line Items]
Basis rate	0.75%
Interest rate	5.00%

Indebtedness (Future Maturities

Indebtedness (Future Maturities On Debt) (Details) $ in Thousands	Mar. 31, 2021USD ($)
Indebtedness [Abstract]
2021 (excluding the three months ended March 31, 2021)	$ 6,667
2022	20,000
2023	20,000
2024	13,333
Total long-term debt, of which $11,667 is current and $48,333 is noncurrent	60,000
Current	11,667
Noncurrent	$ 48,333

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Oct. 31, 2015
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 1,622	$ 1,914
Operating lease liabilities	$ 966	$ 1,180
Letter of credit outstanding			$ 1,250
Minimum [Member]
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Remaining lease terms	10 years

Leases (Summary Of Weighted Ave

Leases (Summary Of Weighted Average Remaining Lease Term And Discount Rate) (Details)	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Leases, Weighted average remaining lease term (years)	3 years 3 months 18 days	3 years 2 months 12 days
Operating Leases, Weighted average discount rate	5.69%	5.68%
Finance Leases, Weighted average remaining lease term (years)	9 years 4 months 24 days	9 years 8 months 12 days
Finance Leases, Weighted average discount rate	6.91%	6.91%

Leases (Summary Of Components O

Leases (Summary Of Components Of Lease Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease cost	$ 279	$ 349
Amortization of right-of-use assets	256	263
Interest on lease liabilities	203	216
Total finance lease cost	$ 459	$ 479

Leases (Summary Of Supplemental

Leases (Summary Of Supplemental Cash Flow Information Related To Leases) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating cash flows from operating leases	$ 331	$ 372
Operating cash flows from finance leases	203	216
Financing cash flows from finance leases	$ 198	$ 94

Leases (Summary Of Supplement_2

Leases (Summary Of Supplemental Balance Sheet Information Related To Leases) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 1,622	$ 1,914
Other current liabilities and current maturities of debt and leases	796	927
Operating lease liabilities	966	1,180
Total operating lease liabilities	1,762	2,107
Finance Leases, Property and equipment, at cost	14,650	14,659
Finance Leases, Accumulated depreciation	(5,396)	(5,247)
Finance Leases, Property and equipment, net	9,254	9,412
Other current liabilities and current maturities of debt and leases	845	823
Finance lease liabilities	10,749	10,969
Total finance lease liabilities	$ 11,594	$ 11,792

Leases (Schedule Of Maturities

Leases (Schedule Of Maturities Of Lease Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Operating Leases
2021 (excluding the three months ended March 31, 2021)	$ 596
2022	637
2023	239
2024	246
2025	253
Total payments	1,971
Less imputed interest	(209)
Total	1,762	$ 2,107
Finance Leases
2021 (excluding the three months ended March 31, 2021)	1,206
2022	1,629
2023	1,652
2024	1,675
2025	1,625
2026 and thereafter	8,173
Total payments	15,960
Less imputed interest	(4,366)
Total	$ 11,594	$ 11,792

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2021USD ($)	Mar. 31, 2021USD ($)item	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Commitments and Contingencies [Line Items]
Number of royalty agreements | item		1
Royalty expense		$ 722	$ 677
Settlement agreement payment	$ 6,000
Liability related settlement current				$ 6,000
Minimum [Member]
Commitments and Contingencies [Line Items]
Royalty rates		3.00%
Maximum [Member]
Commitments and Contingencies [Line Items]
Royalty rates		5.00%

Revenue (Narrative) (Details)

Revenue (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 59,275	$ 53,225
Terms of sale for end-users	30 days
Terms of sale for distributors	60 days

Income Tax Provision (Narrative

Income Tax Provision (Narrative) (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Provision [Abstract]
Effective tax rate	(0.18%)	(0.05%)
Federal tax at statutory rate	21.00%

Equity Compensation Plans (Narr

Equity Compensation Plans (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021USD ($)itemshares	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based incentive plans | item	2
Total shareholder return period	20 days
Participants purchase limit shares	3,000
Offering period	6 months
Employee Stock Option [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	12,899,000
Shares available for future grants	1,586,000
2014 Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2014 Plan [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting right of shares of common stock	1
Vesting period	3 years
2014 Plan [Member] | Minimum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance stock award threshold, target and maximum payout opportunity percentage	0.00%	0.00%
2014 Plan [Member] | Maximum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance stock award threshold, target and maximum payout opportunity percentage	200.00%	100.00%
2008 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance	387,000
Company's common stock may be purchased at a discount	15.00%
Participants purchase limit value | $	$ 25
First, Second, And Third Anniversaries [Member] | Stock Options, RSA's, and RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	33.30%

Equity Compensation Plans (Shar

Equity Compensation Plans (Share-Based Compensation Expense Related To Employee Share-Based Compensation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	$ 6,604	$ 4,384
Cost of Revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	419	287
Research and Development Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	937	655
Selling, General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	$ 5,248	$ 3,442

Segment and Geographic Inform_3

Segment and Geographic Information (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Europe [Member]
Long-lived assets	$ 1,510	$ 1,693

Segment and Geographic Inform_4

Segment and Geographic Information (Revenue By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	$ 59,275	$ 53,225
Revenue	59,275	53,225
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	50,309	43,473
Revenue	50,309	43,473
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	5,766	5,945
Revenue	5,766	5,945
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	2,873	3,537
Revenue	2,873	3,537
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	327	270
Revenue	327	270
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue recognized from contracts with customers	8,966	9,752
Revenue	$ 8,966	$ 9,752

Segment and Geographic Inform_5

Segment and Geographic Information (Revenue By Product Type) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue from External Customer [Line Items]
Revenue	$ 59,275	$ 53,225
United States [Member]
Revenue from External Customer [Line Items]
Revenue	50,309	43,473
United States [Member] | Open Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	21,075	19,218
United States [Member] | Minimally Invasive Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	8,385	6,561
United States [Member] | Appendage Management [Member]
Revenue from External Customer [Line Items]
Revenue	20,587	17,419
United States [Member] | Ablation And Appendage Management [Member]
Revenue from External Customer [Line Items]
Revenue	50,047	43,198
United States [Member] | Valve Tools [Member]
Revenue from External Customer [Line Items]
Revenue	262	275
International [Member]
Revenue from External Customer [Line Items]
Revenue	8,966	9,752
International [Member] | Open Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	4,417	5,115
International [Member] | Minimally Invasive Ablation [Member]
Revenue from External Customer [Line Items]
Revenue	1,274	1,545
International [Member] | Appendage Management [Member]
Revenue from External Customer [Line Items]
Revenue	3,258	3,062
International [Member] | Ablation And Appendage Management [Member]
Revenue from External Customer [Line Items]
Revenue	8,949	9,722
International [Member] | Valve Tools [Member]
Revenue from External Customer [Line Items]
Revenue	$ 17	$ 30