AtriCure (ATRC) 10-K 17 Feb 22 2021 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 14, 2022	Jun. 30, 2021
Document And Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 3,556.1
Entity Common Stock, Shares Outstanding		46,026,734
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Items 10, 11, 12, 13 and 14 of Part III of this Form 10-K incorporate information by reference from the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission within 120 days after the end of the fiscal year covered by this Form 10-K.
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Central Index Key	0001323885

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor Information [Abstract]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Cincinnati, Ohio

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 43,654	$ 41,944
Short-term investments	75,436	202,274
Accounts receivable, less allowance for credit losses of $1,096	33,021	23,146
Inventories	38,964	35,026
Prepaid and other current assets	5,001	4,347
Total current assets	196,076	306,737
Assets, Noncurrent
Property and equipment, net	31,409	28,290
Operating lease right-of-use assets	4,761	1,914
Long-term investments	104,338	14,178
Intangible assets, net	42,992	128,199
Goodwill	234,781	234,781
Other noncurrent assets	955	440
Total Assets	615,312	714,539
Current liabilities:
Accounts payable	18,597	12,736
Accrued liabilities	36,092	27,984
Other current liabilities and current maturities of debt and leases	1,756	8,417
Total current liabilities	56,445	49,137
Long-term debt	59,741	53,435
Finance lease liabilities	10,082	10,969
Operating lease liabilities	4,068	1,180
Contingent consideration and other noncurrent liabilities	1,220	187,424
Total Liabilities	131,556	302,145
Commitments and contingencies
Stockholders’ Equity:
Common stock, $0.001 par value, 90,000 shares authorized; 46,016 and 45,346 issued and outstanding	46	45
Additional paid-in capital	764,811	742,389
Accumulated other comprehensive (loss) income	(948)	312
Accumulated deficit	(280,153)	(330,352)
Total Stockholders’ Equity	483,756	412,394
Total Liabilities and Stockholders’ Equity	$ 615,312	$ 714,539

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable, allowance for credit losses	$ 1,096
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	46,016,000	45,346,000
Common stock, shares outstanding	46,016,000	45,346,000

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 274,329,000	$ 206,531,000	$ 230,807,000
Cost of revenue	68,469,000	57,222,000	60,472,000
Gross profit	205,860,000	149,309,000	170,335,000
Operating expenses (benefit):
Research and development expenses	48,506,000	43,070,000	41,230,000
Selling, general and administrative expenses	204,649,000	150,829,000	167,143,000
Change in fair value of contingent consideration (Note 3)	(184,800,000)	(357,000)	(4,916,000)
Intangible asset impairment (Note 5)	82,300,000	0	0
Total operating expenses	150,655,000	193,542,000	203,457,000
Income (loss) from operations	55,205,000	(44,233,000)	(33,122,000)
Other income (expense):
Interest expense	(4,918,000)	(4,885,000)	(4,111,000)
Interest income	466,000	1,101,000	2,398,000
Other	(366,000)	(24,000)	(160,000)
Income (loss) before income tax expense	50,387,000	(48,041,000)	(34,995,000)
Income tax expense	188,000	114,000	199,000
Net income (loss)	$ 50,199,000	$ (48,155,000)	$ (35,194,000)
Basic net income (loss) per share (in usd per share)	$ 1.11	$ (1.14)	$ (0.94)
Diluted net income (loss) per share (in usd per share)	$ 1.09	$ (1.14)	$ (0.94)
Weighted average shares outstanding, basic (in shares)	45,066,000	42,125,000	37,589,000
Weighted average shares outstanding, diluted (in shares)	46,039,000	42,125,000	37,589,000
Comprehensive (loss) income:
Unrealized (loss) gain on investments	$ (941,000)	$ (46,000)	$ 137,000
Foreign currency translation adjustment	(319,000)	516,000	(96,000)
Other comprehensive (loss) income	(1,260,000)	470,000	41,000
Net income (loss)	50,199,000	(48,155,000)	(35,194,000)
Comprehensive income (loss), net of tax	$ 48,939,000	$ (47,685,000)	$ (35,153,000)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance, shares at Dec. 31, 2018		38,604,000
Beginning balance at Dec. 31, 2018	$ 249,381	$ 39	$ 496,544	$ (247,003)	$ (199)
Issuance of common stock for SentreHEART acquisition (in shares)		699,000
Issuance of common stock for SentreHEART acquisition	20,307	$ 1	20,306
Issuance of common stock under equity incentive plans (in shares)		248,000
Issuance of common stock under equity incentive plans	(7,831)		(7,831)
Issuance of common stock under employee stock purchase plan (in shares)		104,000
Issuance of common stock under employee stock purchase plan	2,662		2,662
Share-based employee compensation expense	17,977		17,977
Other comprehensive income (loss)	41				41
Net income (loss)	(35,194)			(35,194)
Ending balance, shares at Dec. 31, 2019		39,655,000
Ending balance at Dec. 31, 2019	247,343	$ 40	529,658	(282,197)	(158)
Issuance of common stock through public offering (in shares)		4,574,000
Issuance of common stock through public offering	188,958	$ 5	188,953
Issuance of common stock under equity incentive plans (in shares)		1,013,000
Issuance of common stock under equity incentive plans	(2,194)		(2,194)
Issuance of common stock under employee stock purchase plan (in shares)		104,000
Issuance of common stock under employee stock purchase plan	3,330		3,330
Share-based employee compensation expense	22,642		22,642
Other comprehensive income (loss)	470				470
Net income (loss)	(48,155)			(48,155)
Ending balance, shares at Dec. 31, 2020		45,346,000
Ending balance at Dec. 31, 2020	412,394	$ 45	742,389	(330,352)	312
Issuance of common stock under equity incentive plans (in shares)		589,000
Issuance of common stock under equity incentive plans	(9,836)	$ 1	(9,837)
Issuance of common stock under employee stock purchase plan (in shares)		81,000
Issuance of common stock under employee stock purchase plan	4,181		4,181
Share-based employee compensation expense	28,078		28,078
Other comprehensive income (loss)	(1,260)				(1,260)
Net income (loss)	50,199			50,199
Ending balance, shares at Dec. 31, 2021		46,016,000
Ending balance at Dec. 31, 2021	$ 483,756	$ 46	$ 764,811	$ (280,153)	$ (948)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 50,199,000	$ (48,155,000)	$ (35,194,000)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Share-based compensation expense	28,078,000	22,642,000	17,977,000
Depreciation	7,534,000	7,866,000	7,423,000
Amortization of intangible assets	2,907,000	1,682,000	1,943,000
Amortization of deferred financing costs	759,000	509,000	375,000
Amortization (accretion) of investments	2,482,000	1,236,000	(922,000)
Change in fair value of contingent consideration	(184,800,000)	(357,000)	(4,916,000)
Intangible asset impairment	82,300,000	0	0
Other adjustments to income	1,607,000	1,347,000	2,118,000
Changes in operating assets and liabilities, net of amounts acquired:
Accounts receivable	(10,087,000)	5,087,000	(3,201,000)
Inventories	(4,274,000)	(5,265,000)	(5,151,000)
Other current assets	(700,000)	(477,000)	(1,199,000)
Accounts payable	4,710,000	(1,560,000)	2,790,000
Accrued liabilities	8,271,000	(4,908,000)	3,108,000
Other noncurrent assets and liabilities	(2,766,000)	484,000	(962,000)
Net cash used in operating activities	(13,780,000)	(19,869,000)	(15,811,000)
Cash flows from investing activities:
Purchases of available-for-sale securities	(173,105,000)	(227,045,000)	(73,249,000)
Sales and maturities of available-for-sale securities	206,362,000	75,306,000	100,485,000
Purchases of property and equipment	(9,753,000)	(5,259,000)	(12,182,000)
Proceeds from sale of property and equipment	0	0	39,000
Proceeds from capital grant	0	800,000	0
Cash paid for SentreHEART business combination	0	0	(17,240,000)
Net cash provided by (used in) investing activities	23,504,000	(156,198,000)	(2,147,000)
Cash flows from financing activities:
Proceeds from sale of stock, net of offering costs of $218	0	188,958,000	0
Proceeds from debt borrowings	5,000,000	0	20,000,000
Payments on debt and finance leases	(5,816,000)	(667,000)	(629,000)
Payment of debt fees	(1,171,000)	(35,000)	(329,000)
Proceeds from stock option exercises	8,175,000	10,835,000	1,202,000
Shares repurchased for payment of taxes on stock awards	(18,011,000)	(13,029,000)	(9,033,000)
Proceeds from issuance of common stock under employee stock purchase plan	4,181,000	3,330,000	2,662,000
Proceeds from economic incentive loan	0	0	500,000
Net cash (used in) provided by financing activities	(7,642,000)	189,392,000	14,373,000
Effect of exchange rate changes on cash and cash equivalents	(372,000)	136,000	(163,000)
Net increase (decrease) in cash and cash equivalents	1,710,000	13,461,000	(3,748,000)
Cash and cash equivalents—beginning of period	41,944,000	28,483,000	32,231,000
Cash and cash equivalents—end of period	43,654,000	41,944,000	28,483,000
Supplemental cash flow information:
Cash paid for interest	4,223,000	4,366,000	3,719,000
Cash paid for income taxes, net of refunds	190,000	217,000	259,000
Non-cash investing and financing activities:
Contingent consideration in business combinations	0	0	171,300,000
Stock issuance in business combinations	0	0	20,307,000
Accrued purchases of property and equipment	1,552,000	298,000	1,053,000
Assets obtained in exchange for finance lease obligations	$ 0	$ 22,000	$ 270,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Statement of Cash Flows [Abstract]
Offering cost for sale of stock	$ 218

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Summary of Significant Accounting Policies	DESCRIPTION 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 surgical treatments and therapies for atrial fibrillation (Afib), left atrial appendage (LAA) management and post-operative pain management and sells its products to medical centers globally through its direct sales force and distributors. Principles of Consolidation— The Consolidated Financial Statements include the accounts of AtriCure, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Reclassification —During 2021, the Company changed the presentation of its consolidated statement of operations and comprehensive income (loss) to separately disclose the change in contingent consideration, previously reported in selling, general and administrative expenses. Amounts for comparative prior years have been reclassified to conform to the current period presentation. This reclassification had no impact on previously reported net loss or financial position. 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 financial institutions. Investments— The Company invests primarily in 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 12 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 expected credit losses on 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 regulatory 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. Property and Equipment— Property and equipment is stated at cost less accumulated depreciation. Depreciation is determined using the straight-line method over the estimated useful lives of assets (see Note 7). Maintenance and repair costs are expensed as incurred. The Company assesses the useful lives of property and equipment at least annually and retires assets no longer in use. 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 impairment has not been significant. The Company’s radiofrequency 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 other capital equipment is recorded in cost of revenue. Leases —The Company leases office, manufacturing and warehouse facilities and computer equipment under leases that qualify as either financing or operating leases, as determined at the inception of the lease arrangement. Lease assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make payments under the lease. Lease assets and liabilities are measured and recorded at the commencement date based on the present value of payments over the lease term. Lease assets and liabilities include lease incentives and options to extend or terminate when it is reasonably certain the Company will exercise that option. The Company uses the implicit rate when readily determinable; however, as most leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at measurement. The Company also 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 an option to extend the lease whose exercise is reasonably certain. 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 for the operating leases based on the terms of the underlying leases. Operating leases are included in operating lease right-of-use (ROU) assets and operating lease liabilities, while finance leases are included in property and equipment and finance lease liabilities. The short-term portions of both lease liabilities are included in other current liabilities and current maturities of debt and leases. Operating lease expense is recognized on a straight-line basis over the lease term. See Note 10 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 the 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 converted to a technology asset and amortized over its estimated useful life. Due to the nature of IPR&D projects, the Company may experience future delays or failures to obtain approvals or market clearances, or may discontinue or abandon the project, all of which may impact the estimated fair value of the IPR&D project. As a result, the Company may have a full or partial impairment charge related to the IPR&D, determined as the excess carrying value of the IPR&D asset 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. Through April 2021, the IPR&D asset included an estimate of the fair value of the pre-market approval (PMA) that could result from the CONVERGE IDE and aMAZE IDE clinical trials. The Company received PMA approval for CONVERGE on April 28, 2021 and began amortizing the $44,021 technology asset over an estimated fifteen year life. During the year ended December 31, 2021, the Company identified indicators of impairment for the IPR&D asset that represented an estimate of the fair value of the PMA that could result from the aMAZE clinical trial. As a result of the analysis performed, the Company recorded an impairment loss of $82,300. See Note 3 for further discussion. 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 asset retirement obligations and other contractual obligations. The balance in prior periods also includes 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). The contingent consideration balance is included in noncurrent liabilities as any settlement is expected to be made primarily in shares of the Company’s common stock pursuant to the 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. Income 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 a 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 by considering all available evidence. 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, taxable income in prior carryback years 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 for a valuation allowance. The Company's valuation allowance offsets 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. Earnings Per Share— Basic earnings per share is computed by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share reflects net income available to common stockholders divided by the weighted average number of common shares outstanding during the period and any dilutive common share equivalents, including shares issuable upon the vesting of restricted stock awards and restricted stock units, exercise of stock options as well as shares issuable under the Company's employee stock purchase plan (ESPP). Year Ended December 31, 2021 2020 2019 Net income (loss) available to common stockholders $ 50,199 $ (48,155) $ (35,194) Basic weighted average common shares outstanding 45,066 42,125 37,589 Effect of dilutive securities 973 — — Diluted weighted average common shares outstanding 46,039 42,125 37,589 Basic net income (loss) per common share $ 1.11 $ (1.14) $ (0.94) Diluted net income (loss) per common share $ 1.09 $ (1.14) $ (0.94) The computation of diluted earnings per share in the year ended December 31, 2021 excludes 404 shares because the effect would be anti-dilutive. For the years ended December 31, 2020 and 2019, the number of shares calculated for basic net loss per share is also used for the diluted net loss per share calculation, and net loss per share excludes the effect of 2,301 and 3,623 shares because the effect would be anti-dilutive. Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)— In addition to net income (loss), the comprehensive income (loss) includes foreign currency translation adjustments and unrealized gains (losses) on investments. Accumulated other comprehensive (loss) income consisted of the following, net of tax: 2021 2020 2019 Total accumulated other comprehensive income (loss) at beginning of period $ 312 $ (158) $ (199) Unrealized gains (losses) on investments Balance at beginning of period $ 54 $ 100 $ (37) Other comprehensive (loss) income before reclassifications (941) (70) 137 Amounts reclassified from accumulated other comprehensive income (loss) to interest income — 24 — Balance at end of period $ (887) $ 54 $ 100 Foreign currency translation adjustment Balance at beginning of period $ 258 $ (258) $ (162) Other comprehensive (loss) income before reclassifications (768) 555 (277) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) 449 (39) 181 Balance at end of period $ (61) $ 258 $ (258) Total accumulated other comprehensive (loss) income at end of period $ (948) $ 312 $ (158) 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 and research of new and existing products or concepts, preclinical studies, clinical trials and related regulatory activities, as well as amortization of technology assets. Advertising Costs — The Company expenses advertising costs as incurred. Advertising expense was $907, $655 and $635 during the years ended December 31, 2021, 2020 and 2019. Share-Based Compensation— The Company recognizes share-based compensation expense for all share-based payment awards, including stock options, restricted stock awards, restricted stock units, performance share awards (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 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 several subjective assumptions, such as 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 target will be achieved and may adjust expense over the performance period based on changes to estimates of performance target achievement. If such targets are not met or service is not rendered for the requisite service period, no compensation cost is recognized, and any recognized compensation cost in prior periods 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 stock price, as defined by the award agreement, 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 accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, including intangible assets, contingent assets and liabilities 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 Disclosures —The Company classifies cash investments in U.S. government and agency obligations, accounts receivable, short-term other assets, accounts payable and accrued liabilities as Level 1. The carrying amounts of these assets and liabilities approximate their fair value due to their relatively short-term nature. Cash equivalents and investments in corporate bonds, repurchase agreements, 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. Significant unobservable inputs with respect to the fair value measurements of the Level 3 contingent consideration liabilities are developed using Company data. See Note 3 – Fair Value for further information on fair value measurements.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2021
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTSIn November 2021, the FASB issued Accounting Standard Update (ASU) 2021-10, “Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance” (ASU 2021-10). This guidance requires business entities to provide certain disclosures when they have received government assistance and use a grant or contribution accounting model by analogy to other accounting guidance. The guidance becomes effective for annual reporting periods beginning after December 15, 2021. The Company does not expect the adoption of this standard to have a material impact on its consolidated financial statements and related disclosures.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE FASB ASC 820, “Fair Value Measurements and Disclosures” (ASC 820), defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The 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 that the Company has the ability to access at the measurement date. An active market for the asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. The valuation under this approach does not entail a significant degree of judgment. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The valuation technique for the Company’s Level 2 assets is based on quoted market prices for similar assets from observable pricing sources at the reporting date. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Unobservable inputs shall be used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. The 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, 2021: Quoted Prices Significant Significant Total Assets: Money market funds $ — $ 38,360 $ — $ 38,360 Commercial paper — 22,978 — 22,978 Government and agency obligations 32,690 — — 32,690 Corporate bonds — 95,845 — 95,845 Asset-backed securities — 28,261 — 28,261 Total assets $ 32,690 $ 185,444 $ — $ 218,134 Liabilities: Contingent consideration $ — $ — $ — $ — Total liabilities $ — $ — $ — $ — 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 Significant Significant Total Assets: Money market funds $ — $ 38,452 $ — $ 38,452 Commercial paper — 76,914 — 76,914 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 There were no changes in the levels or methodology of measurement of financial assets and liabilities during the years ended December 31, 2021 and 2020. Contingent Consideration. The Company's contingent consideration arrangements arising from the SentreHEART acquisition 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 follows: • PMA Milestone – up to $140,000 upon receiving PMA from FDA for the LARIAT system with an approved indication allowing commercial distribution in the United States for the exclusion of the LAA for treatment of atrial fibrillation. The full contingent consideration amount is only received if PMA approval is received on or before December 31, 2022. The potential contingent consideration is reduced by 4.17% (or one-twenty-fourth) each month following December 2022 and is reduced to zero if the milestone is achieved after December 31, 2023. Payment of $25,000 of the PMA milestone may be accelerated upon achievement of an Interim Success Milestone as defined by the merger agreement. • CPT Reimbursement Milestone – up to $120,000 upon American Medical Association approval of a Medicare Category 1 Current Procedural Terminology (CPT) Code. The full contingent consideration amount is only received if approval of the CPT Code is received on or before December 31, 2025. The potential contingent consideration is reduced by 4.17% (or one-twenty-fourth) each month following December 2025 and is reduced to zero if the milestone is achieved after December 31, 2026. Subject to the terms and conditions of the SentreHEART merger agreement, all contingent consideration would be paid in cash and stock at the discretion of the Company, subject to certain minimums and limitations, with the maximum number of shares that may be issued after closing limited to 6,322, representing total shares that may be issued in connection with the merger of 7,021 less 699 shares paid at closing. The maximum contingent consideration payable by AtriCure will not exceed $260,000. 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 significant to 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. Contingent consideration liabilities are periodically measured, with changes in the estimated fair value reflected in operating expenses. Changes in the discount rate, projected 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. In July 2021, the Company was informed that data from the aMAZE clinical trial did not achieve statistical superiority. Specifically, while the trial met the safety endpoint, the trial did not meet the primary effectiveness endpoint. As the contingent consideration arrangements were success-based milestone payments, the fair value of the SentreHEART contingent consideration was remeasured as of September 30, 2021 resulting in a decrease in fair value due to changes in estimates related to both the forecasted timing and probability of achievement of the regulatory and reimbursement milestones. Accordingly, the Company recorded a credit to operating expenses of $184,800 reflecting the change in fair value of the contingent consideration. The Company has assessed the projected probability of payment during the contractual achievement periods to be remote, resulting in no remaining fair value as of December 31, 2021. The following table represents the Company’s Level 3 fair value measurements using significant other unobservable inputs for acquisition-related contingent consideration for each of the years ended December 31: 2021 2020 2019 Beginning Balance – January 1 $ 184,800 $ 185,157 $ 18,773 Amounts acquired $ — $ — $ 171,300 Changes in fair value of contingent consideration (184,800) (357) (4,916) Ending Balance – December 31 $ — $ 184,800 $ 185,157

Investments

Investments	12 Months Ended
	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Investments	INVESTMENTS Investments as of December 31, 2021 consisted of the following: Cost Basis Unrealized Fair Value Corporate bonds $ 96,408 $ (563) $ 95,845 Government and agency obligations 32,953 (263) 32,690 Commercial paper 22,978 — 22,978 Asset-backed securities 28,322 (61) 28,261 Total $ 180,661 $ (887) $ 179,774 Investments as of December 31, 2020 consisted of the following: Cost Basis Unrealized Fair Value Corporate bonds $ 73,702 $ 28 $ 73,730 Government and agency obligations 45,385 14 45,399 Commercial paper 76,914 — 76,914 Asset-backed securities 20,397 12 20,409 Total $ 216,398 $ 54 $ 216,452 The Company has not experienced any significant realized gains or losses on its investments in the years ended December 31, 2021, 2020 and 2019.

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	INTANGIBLE ASSETS AND GOODWILL The following table provides a summary of the Company’s intangible assets at December 31: 2021 2020 Estimated Useful Life Cost Accumulated Amortization Cost Accumulated Amortization Technology 5-15 years $ 55,712 $ 12,720 $ 11,691 $ 9,813 IPR&D — — 126,321 — Total $ 55,712 $ 12,720 $ 138,012 $ 9,813 Following PMA approval of the EPi-Sense ® System in the second quarter 2021, the related IPR&D asset with a value of $44,021 was determined to have a finite useful life. The intangible asset is now included in technology assets and amortized over an estimated fifteen year life. As a result of data from the aMAZE clinical trial not achieving statistical superiority, the Company identified indicators of impairment for the IPR&D asset that represents an estimate of the fair value of the PMA that could result from the aMAZE clinical trial. During the third quarter 2021, an impairment test was performed using estimates based on reasonable and supportable assumptions and projections of expected future cash flows, and the Company recorded an impairment charge of $82,300, reducing the carrying value of the aMAZE IPR&D asset to $0 as of December 31, 2021. This impairment charge is reflected as a component of operating expenses. Amortization expense of intangible assets with definite lives, which excludes IPR&D assets, was $2,907, $1,682 and $1,943 for the years ended December 31, 2021, 2020 and 2019. Future amortization expense is projected as follows: 2022 $ 3,653 2023 2,953 2024 2,953 2025 2,953 2026 2,953 2027 and thereafter 27,527 Total $ 42,992 The following table provides a summary of the Company’s goodwill, which is not amortized, but rather tested annually for impairment: Net carrying amount as of December 31, 2019 $ 234,781 Additions — Net carrying amount as of December 31, 2020 234,781 Additions — Net carrying amount as of December 31, 2021 $ 234,781

Inventories

Inventories	12 Months Ended
	Dec. 31, 2021
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consisted of the following at December 31: 2021 2020 Raw materials $ 12,653 $ 11,966 Work in process 2,064 2,424 Finished goods 24,247 20,636 Inventories $ 38,964 $ 35,026

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment	PROPERTY AND EQUIPMENT Property and equipment consisted of the following at December 31: Estimated Useful Life 2021 2020 Generators and related equipment 1 - 3 years $ 20,175 $ 18,669 Building under finance lease 15 years 14,250 14,250 Computer, software and office equipment 3 - 5 years 7,762 8,045 Machinery and equipment 3 - 7 years 8,501 6,697 Furniture and fixtures 3 - 7 years 5,877 5,849 Leasehold improvements 5 - 15 years 8,727 8,645 Construction in progress N/A 5,999 2,067 Land N/A 1,006 502 Equipment under finance leases 3 - 5 years 380 409 Total 72,677 65,133 Less accumulated depreciation (41,268) (36,843) Property and equipment, net $ 31,409 $ 28,290 Property and equipment depreciation expense was $7,534, $7,866 and $7,423 for the years ended December 31, 2021, 2020 and 2019. Depreciation related to generators and other capital equipment was $2,327, $2,503 and $2,910 for

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued Liabilities	ACCRUED LIABILITIES Accrued liabilities consisted of the following at December 31: 2021 2020 Accrued compensation and employee-related expenses $ 30,990 $ 17,730 Sales returns and allowances 2,416 1,889 Accrued taxes and value-added taxes payable 1,452 1,256 Accrued royalties 754 703 Other accrued liabilities 470 406 Accrued legal settlement 10 6,000 Total $ 36,092 $ 27,984

Indebtedness

Indebtedness	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Indebtedness	INDEBTEDNESS Credit Facility. The Company has a Loan and Security Agreement, as amended and modified effective February 8, 2021 and as further amended November 1, 2021 (Loan Agreement) with Silicon Valley Bank (SVB). The Loan Agreement includes a $60,000 term loan, with an option to make available an additional $30,000 in term loan borrowings, and a $30,000 revolving line of credit. The Loan Agreement has a five year term, expiring November 2026. Principal payments under the Loan Agreement are to be made ratably commencing 24 months after inception through the loan's maturity date. At the option of the Company, the commencement of term loan principal payments may be extended an additional twelve months. The term loan accrues interest at the Prime Rate plus 1.25% and is subject to an additional 3.00% fee on the term loan principal amount at maturity. The Company is accruing the 3.00% fee over the term of the Loan Agreement, with $60 included in the outstanding loan balance as of December 31, 2021. Additionally, the unamortized original financing costs related to the term loan of $319 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 0.20% of the revolving line of credit, and any borrowings thereunder bear interest at the Prime Rate. Borrowing availability under the revolving credit facility is based on the lesser of $30,000 or a borrowing base calculation as defined by the Loan Agreement. As of December 31, 2021, the Company had no borrowings under the revolving credit facility and had borrowing availability of approximately $28,750. 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, excluding the term loan final fee, are projected as follows: 2022 $ — 2023 3,333 2024 20,000 2025 20,000 2026 16,667 Total long-term debt, of which $60,000 is noncurrent $ 60,000

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lessee, Operating Leases	LEASESThe 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 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 are as follows: As of As of As of December 31, 2021 December 31, 2020 December 31, 2019 Operating Leases Weighted average remaining lease term (years) 3.6 3.2 3.5 Weighted average discount rate 4.69 % 5.68 % 5.94 % Finance leases Weighted average remaining lease term (years) 8.6 9.7 11.0 Weighted average discount rate 6.91 % 6.91 % 7.05 % A letter of credit for $1,250 was issued to the lessor of the Company's corporate headquarters building in October 2015, which is renewed annually and remains outstanding as of December 31, 2021. The components of lease expense are as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Operating lease cost $ 1,052 $ 1,237 $ 952 Finance lease cost: Amortization of right-of-use assets 1,019 1,050 998 Interest on lease liabilities 792 844 872 Total finance lease cost $ 1,811 $ 1,894 $ 1,870 Short term lease expense was not significant for the twelve months ended December 31, 2021, 2020 and 2019. Supplemental cash flow information related to leases was as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 998 $ 1,236 $ 1,026 Operating cash flows for finance leases 620 844 872 Financing cash flows for finance leases 792 664 629 Right-of-use assets obtained in exchange for lease obligations: Operating Leases 3,752 1,421 1,884 Finance Leases — 22 270 Operating lease right-of-use asset obtained in business combination — — 2,929 Early termination of operating lease — 2,743 — Supplemental balance sheet information related to leases was as follows: As of December 31, 2021 As of December 31, 2020 Operating Leases Operating lease right-of-use assets $ 4,761 $ 1,914 Other current liabilities and current maturities of debt and leases 861 927 Operating lease liabilities 4,068 1,180 Total operating lease liabilities $ 4,929 $ 2,107 Finance Leases Property and equipment, at cost $ 14,607 $ 14,659 Accumulated depreciation (6,116) (5,247) Property and equipment, net $ 8,491 $ 9,412 Other current liabilities and current maturities of debt and leases $ 895 $ 823 Finance lease liabilities 10,082 10,969 Total finance lease liabilities $ 10,977 $ 11,792 Maturities of lease liabilities as of December 31, 2021 were as follows: Operating Leases Finance Leases 2022 $ 861 $ 1,629 2023 1,160 1,652 2024 1,164 1,674 2025 920 1,625 2026 592 1,657 2027 and thereafter 868 6,515 Total payments $ 5,565 $ 14,752 Less imputed interest (636) (3,775) Total $ 4,929 $ 10,977
Lessee, Finance Leases	LEASESThe 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 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 are as follows: As of As of As of December 31, 2021 December 31, 2020 December 31, 2019 Operating Leases Weighted average remaining lease term (years) 3.6 3.2 3.5 Weighted average discount rate 4.69 % 5.68 % 5.94 % Finance leases Weighted average remaining lease term (years) 8.6 9.7 11.0 Weighted average discount rate 6.91 % 6.91 % 7.05 % A letter of credit for $1,250 was issued to the lessor of the Company's corporate headquarters building in October 2015, which is renewed annually and remains outstanding as of December 31, 2021. The components of lease expense are as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Operating lease cost $ 1,052 $ 1,237 $ 952 Finance lease cost: Amortization of right-of-use assets 1,019 1,050 998 Interest on lease liabilities 792 844 872 Total finance lease cost $ 1,811 $ 1,894 $ 1,870 Short term lease expense was not significant for the twelve months ended December 31, 2021, 2020 and 2019. Supplemental cash flow information related to leases was as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 998 $ 1,236 $ 1,026 Operating cash flows for finance leases 620 844 872 Financing cash flows for finance leases 792 664 629 Right-of-use assets obtained in exchange for lease obligations: Operating Leases 3,752 1,421 1,884 Finance Leases — 22 270 Operating lease right-of-use asset obtained in business combination — — 2,929 Early termination of operating lease — 2,743 — Supplemental balance sheet information related to leases was as follows: As of December 31, 2021 As of December 31, 2020 Operating Leases Operating lease right-of-use assets $ 4,761 $ 1,914 Other current liabilities and current maturities of debt and leases 861 927 Operating lease liabilities 4,068 1,180 Total operating lease liabilities $ 4,929 $ 2,107 Finance Leases Property and equipment, at cost $ 14,607 $ 14,659 Accumulated depreciation (6,116) (5,247) Property and equipment, net $ 8,491 $ 9,412 Other current liabilities and current maturities of debt and leases $ 895 $ 823 Finance lease liabilities 10,082 10,969 Total finance lease liabilities $ 10,977 $ 11,792 Maturities of lease liabilities as of December 31, 2021 were as follows: Operating Leases Finance Leases 2022 $ 861 $ 1,629 2023 1,160 1,652 2024 1,164 1,674 2025 920 1,625 2026 592 1,657 2027 and thereafter 868 6,515 Total payments $ 5,565 $ 14,752 Less imputed interest (636) (3,775) Total $ 4,929 $ 10,977

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Royalty Agreements. The Company has royalty agreements in place with terms that include payments of 3% to 5% of specified product sales. One royalty agreement remains in effect through 2025, while the other agreement remains in effect until the later of 2023 or 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 $3,124, $2,596 and $2,892 was recorded for the years ended December 31, 2021, 2020 and 2019. Purchase Agreements. The Company enters into standard purchase agreements with suppliers in the ordinary course of business, generally with terms that allow cancellation. The Company is committed to funding renovation of a recently purchased building for additional manufacturing capacity. Approximately $3,800 of construction costs remain committed and outstanding. 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. A liability is established once management determines a loss is probable and an amount can be reasonably estimated. 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 on behalf of the United States and the various state and local government under the qui tam provisions of federal and certain state and local False Claims Acts. Although the USDOJ and all of the state and local governments declined to intervene, the relator continues to pursue the case. The Company is vigorously contesting the case, however, 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 provided 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, and has made substantially all of the settlement payment as of December 31, 2021.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	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. Revenue includes shipping and handling revenue of $1,354, $1,192 and $1,485 in the years ended December 31, 2021, 2020 and 2019. 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 the Company believes could impact its 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 included in selling expense while royalties are included in cost of revenue. See Note 17 for disaggregated revenue by geographic area and by product category.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES 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 in accordance with FASB ASC 740, “Income Taxes”, under which deferred income taxes are provided for the temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities. Deferred taxes are measured using provisions of currently enacted tax laws. A valuation allowance against deferred tax assets is recorded when it is more likely than not that such assets will not be fully realized. The Company's valuation allowance offsets substantially all its net deferred tax assets as it is more likely than not that the benefit of the deferred tax assets will not be recognized in future periods. The Company’s provision for income taxes for each of the years ended December 31 is as follows: 2021 2020 2019 Current Tax Expense Federal $ — $ (26) $ (26) State 42 78 34 Foreign 125 74 165 Total current tax expense 167 126 173 Deferred Tax Expense Federal $ (30,925) $ (10,304) $ (7,655) State (4,803) (1,686) (1,368) Foreign (826) (3,071) (1,690) Change in valuation allowance 36,575 15,049 10,739 Total deferred tax expense 21 (12) 26 Total tax expense $ 188 $ 114 $ 199 The detail of deferred tax assets and liabilities at December 31 is as follows: 2021 2020 Deferred tax assets (liabilities): Net operating loss carryforwards $ 137,920 $ 123,556 Research and development credit carryforwards 11,269 9,365 Intangible assets (9,993) (30,773) Equity compensation 7,974 8,623 Finance and operating lease liabilities 3,700 3,164 Right-of-use assets (3,037) (2,547) Deferred interest 2,469 1,598 Inventories 2,434 1,360 Accruals and reserves 1,755 3,739 Property and equipment (1,264) (1,315) Other 587 293 Subtotal 153,814 117,063 Less valuation allowance (153,798) (117,025) Total $ 16 $ 38 The Company has federal net operating loss carryforwards of $336,792 which expire between 2022 and 2037 and $175,883 which has no expiration. The Company has state and local net operating loss carryforwards of $344,968 which expire between 2022 to 2041. A portion of the Company’s federal and state net operating loss carryforwards are subject to certain limitations under Internal Revenue Code Sections 382 and 383. The Company has federal research and development credit carryforwards of $11,269 which expire between 2022 and 2041. Additionally, the Company has foreign net operating loss carryforwards of approximately $50,817 which expire between 2022 and 2027. The Company’s 2021, 2020 and 2019 effective income tax rates differ from the federal statutory rate as follows: 2021 2020 2019 Federal tax at statutory rate 21.0% $ 10,580 21.0% $ (10,088) 21.0% $ (6,950) Permanent differences (80.3)% (40,439) (2.5)% 1,214 1.2 % (386) Valuation allowance 72.6 % 36,575 (31.3) % 15,048 (32.4) % 10,739 State income taxes (9.4)% (4,760) 3.3% (1,607) 4.0 % (1,334) Federal R&D credit (3.7)% (1,878) 2.0% (985) 2.5% (837) Foreign income taxes 0.7% 344 4.5 % (2,140) (0.2) % 52 Federal deferred adjustments (0.5)% (234) 2.8 % (1,328) 3.3 % (1,085) Effective tax rate 0.4 % $ 188 (0.2) % $ 114 (0.6) % $ 199 The Company’s pre-tax book loss for domestic and international operations was $55,666 and $(5,279) for 2021, $(43,218) and $(4,823) for 2020 and $(28,002) and $(6,993) for 2019. The Company had undistributed earnings of foreign subsidiaries of approximately $290 at December 31, 2021. The Company does not consider these earnings as permanently reinvested and has determined that no current and deferred taxes are required on such amounts. Federal, state and local tax returns of the Company are routinely subject to examination by various taxing authorities. Federal income tax returns for periods beginning in 2018 are open for examination. Generally, state and foreign income tax returns for periods beginning in 2017 are open for examination. However, taxing authorities have the ability to audit net operating loss and tax credit carryforwards from years prior to these periods. The Company has not recognized certain tax benefits because of the uncertainty of realizing the entire value of the tax position taken on income tax returns upon review by the taxing authorities. A reconciliation of the change in federal and state unrecognized tax benefits for 2021, 2020 and 2019 is presented below: 2021 2020 2019 Balance at the beginning of the year $ 1,798 $ 1,777 $ 1,157 Increases (decreases) for prior year tax positions — 21 620 Increases (decreases) for current year tax positions — — — Increases (decreases) related to settlements — — — Decreases related to statute lapse — — — Balance at the end of the year $ 1,798 $ 1,798 $ 1,777 The increase in unrecognized tax benefits in 2019 relates to uncertain income tax benefits assumed pursuant to the SentreHEART acquisition. Historically, the Company has not incurred any significant interest and penalties for unrecognized income tax benefits as a result of offsetting net operating losses. Interest and penalties associated with uncertain income tax benefits assumed pursuant to the SentreHEART acquisition were recognized as part of purchase accounting. The amount is not significant. The balance of unrecognized tax benefits at December 31, 2021, 2020 and 2019 includes $1,798, $1,798 and $1,777 of tax benefits that, if recognized, would result in adjustments to other tax accounts, primarily deferred taxes and valuation allowance. The Company does not expect that its unrecognized tax benefits for research credits will significantly change within twelve months of December 31, 2021.

Concentrations

Concentrations	12 Months Ended
	Dec. 31, 2021
Risks and Uncertainties [Abstract]
Concentrations	CONCENTRATIONS During 2021, 2020 and 2019, approximately 10.5%, 10.8% and 12.0% of the Company’s total net revenue was derived from its top ten customers. During 2021, 2020 and 2019 no individual customer accounted for more than 10% of the Company’s revenue. As of December 31, 2021 and 2020, 16.0% and 13.0% of the Company’s total accounts receivable balance was derived from its top ten customers. No individual customer accounted for more than 10% of the Company’s accounts receivable as of December 31, 2021 and 2020. The Company maintains cash and cash equivalents balances at financial institutions which at times exceed FDIC limits. As of December 31, 2021, $43,404 of the cash and cash equivalents balance was in excess of the FDIC limits.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANSThe Company sponsors the AtriCure, Inc. 401(k) Plan (401(k) Plan), a defined contribution plan covering substantially all U.S. employees of the Company. Eligible employees may contribute pre-tax annual compensation up to specified maximums under the Internal Revenue Code. During the year ended December 31, 2021, 2020 and 2019, the Company made matching contributions of 50% on the first 6% of employee contributions to the 401(k) Plan. The Company’s matching contributions in 2021, 2020 and 2019 were $2,651, $2,237 and $1,915. Additional amounts may be contributed to the 401(k) Plan at the discretion of the Company’s Board of Directors, however, no such discretionary contributions were made in 2021, 2020 or 2019. The Company also provides retirement benefits for employees of AtriCure Europe B.V. and other foreign subsidiaries. Total contributions to retirement plans for these employees were $349, $244 and $248 in 2021, 2020 and 2019.

Equity Compensation Plans

Equity Compensation Plans	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Equity Compensation Plans	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 Compensation Committee of the Board of Directors, as the administrator of the 2014 Plan, 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 December 31, 2021, 12,899 shares of common stock had been reserved for issuance under the 2014 Plan and 1,505 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. Performance options expire ten years from the date of grant and vest in increments of 25 shares when the volume adjusted weighted average closing price of the common stock of the Company as reported by NASDAQ (or any other exchange on which the common stock of the Company is listed) for 30 consecutive days equals or exceeds specified amounts. A Monte Carlo simulation was performed to estimate the fair values, vesting terms and vesting probabilities for each tranche of options. Expense calculated using these estimates was recognized over the estimated vesting terms. As of December 31, 2017, compensation costs related to non-vested performance options were fully recognized. 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 determine 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) over the three year performance period. 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 payout defined in the PSA agreements. Activity under the plans during 2021 was as follows: Weighted Weighted Average Number of Average Remaining Aggregate Shares Exercise Contractual Intrinsic Time-Based Stock Options Outstanding Price Term Value Outstanding at January 1, 2021 904 $ 16.57 Granted 100 70.00 Exercised (333) 13.48 Cancelled (18) 46.76 Outstanding at December 31, 2021 653 $ 25.53 4.4 $ 29,071 Vested and expected to vest 647 $ 25.18 4.4 $ 29,023 Exercisable at December 31, 2021 520 $ 16.67 3.3 $ 27,513 Weighted Weighted RSA Average PSA Average Shares Grant Date Shares Grant Date Restricted Stock Awards and Performance Share Awards Outstanding Fair Value Outstanding Fair Value Outstanding at January 1, 2021 935 $ 30.92 287 $ 39.70 Awarded 306 67.51 99 89.36 Released (595) 28.73 (117) 38.51 Forfeited (18) 45.73 (42) 57.08 Outstanding at December 31, 2021 628 $ 50.96 227 $ 64.27 Weighted Weighted Average Number of Average Remaining Aggregate Shares Exercise Contractual Intrinsic Performance Stock Options Outstanding Price Term Value Outstanding at January 1, 2021 175 21.04 Granted — — Exercised (175) 21.04 Cancelled — — Outstanding at December 31, 2021 — $ — 0 $ — Exercisable at December 31, 2021 — $ — 0 $ — The total intrinsic value of options exercised during the years ended December 31, 2021, 2020 and 2019 was $27,318, $29,594 and $1,985. As a result of the Company’s full valuation allowance on its net deferred tax assets, no tax benefit was recognized related to the stock option exercises. The exercise price per share of each option is equal to the fair market value of the underlying share on the date of grant. For 2021, 2020 and 2019, $8,175, $10,835 and $1,202 in cash proceeds from the exercise of stock options were included in the Consolidated Statements of Cash Flows. The total fair value of restricted stock vested during 2021, 2020 and 2019 was $40,510, $34,200 and $23,479. The total fair value of performance share awards vested during 2021 and 2020 was $8,165 and $4,003. The Company issues registered shares of common stock to satisfy stock option exercises and restricted stock and performance award grants. Employee Stock Purchase Plan Under the ESPP, shares of the Company’s common stock may be purchased at a discount (15%) to the lesser of the closing price of the Company’s common stock on the first or 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 December 31, 2021, there were 305 shares available for future issuance under the ESPP. Valuation and Expense Information Under FASB ASC 718 The following table summarizes share-based compensation expense related to employees, directors and consultants for 2021, 2020 and 2019. The expense was allocated as follows: 2021 2020 2019 Cost of revenue $ 2,243 $ 1,425 $ 917 Research and development expenses 4,206 3,530 2,374 Selling, general and administrative expenses 21,629 17,687 14,686 Total $ 28,078 $ 22,642 $ 17,977 The expense by award type was allocated as follows: 2021 2020 2019 Restricted Stock Awards & Time-Based Stock Options $ 18,727 $ 18,612 $ 13,922 Performance Share Awards 8,095 2,921 3,254 ESPP 1,256 1,109 801 Total $ 28,078 $ 22,642 $ 17,977 In 2020, the Compensation Committee modified the methodology for measuring performance of the 2018, 2019 and 2020 performance awards. The modification to vesting conditions and performance measures resulted in incremental compensation cost of $2,856 and $569 during 2021 and 2020. As of December 31, 2021 there was $21,687 of unrecognized compensation costs related to non-vested stock options and restricted stock arrangements ($2,341 relating to stock options and $19,346 relating to restricted stock). This cost is expected to be recognized over a weighted-average period of 2.2 years for stock options and 1.8 years for restricted stock. As of December 31, 2021 there was $10,301 of unrecognized compensation costs related to non-vested performance share awards, and this cost is expected to be recognized over a weighted-average period of 1.8 years. In determining compensation expense, the fair value of restricted stock awards, restricted stock units and performance share awards with a performance condition is based on the market value of the Company’s stock on the grant date of the awards or subsequent modification (as applicable). The fair value of options is estimated on the grant date using the Black-Scholes model and includes the following assumptions: 2021 2020 2019 Range of risk-free interest rate 0.43-1.22% 0.30-1.73% 1.43 - 2.64% Range of expected life of stock options (years) 5.3 to 5.7 5.2 to 5.7 5.1 to 5.7 Range of expected volatility of stock 40.00 - 43.00% 40.00 - 43.00% 40.00 - 42.00% Weighted-average volatility 41.84% 41.54% 40.87% Dividend yield 0.00% 0.00% 0.00% The Company’s estimate of volatility is based solely on the Company’s trading history over the expected option life. The risk-free interest rate assumption is based upon the U.S. treasury yield curve at the time of grant for the expected option life. The Company estimates the expected terms of options using historical employee exercise behavior. The fair value of performance share awards with a market condition is estimated on the grant date using a Monte Carlo simulation and includes the following assumptions: 2021 Stock price $ 66.31 Expected term (years) 2.8 Company volatility 42.10% Peer group average volatility 91.00% Peer group average correlation 31.50% Risk-free interest rate 0.20% Dividend yield 0.00% The expected term is estimated as the remaining performance period at the grant date. Expected volatility is estimated based on the Company and peer group's daily trading prices, adjusted for dividends and stock splits over the remaining performance period. The risk-free interest rate is based upon the US Constant Maturity yield curve at the time of grant for the expected term of the performance share awards. Based on the assumptions noted above, the weighted average estimated grant date fair value per share of the stock options, restricted stock awards and performance share awards granted for 2021, 2020 and 2019 was as follows: 2021 2020 2019 Stock options $ 27.31 $ 15.25 $ 11.56 Restricted stock awards 67.51 40.77 30.12 Performance share awards 89.36 38.42 30.77

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment and Geographic Information	SEGMENT AND GEOGRAPHIC INFORMATION The Company evaluates reporting segments in accordance with FASB ASC 280, “Segment Reporting”. The Company develops, manufactures and sells devices designed primarily for the surgical ablation of cardiac tissue, systems designed for the exclusion of the left atrial appendage and devices designed to block pain by temporarily ablating peripheral nerves. 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 customer geographic locations is as follows: 2021 2020 2019 United States $ 229,131 $ 169,244 $ 185,829 Europe 27,931 23,217 27,929 Asia 16,077 13,118 15,976 Other international 1,190 952 1,073 Total international 45,198 37,287 44,978 Total revenue $ 274,329 $ 206,531 $ 230,807 United States revenue by product type is as follows: 2021 2020 2019 Open ablation $ 93,895 $ 75,399 $ 80,205 Minimally invasive ablation 39,380 25,647 34,842 Appendage management 94,568 66,981 68,166 Total ablation and appendage management 227,843 168,027 183,213 Valve tools 1,288 1,217 2,616 Total United States $ 229,131 $ 169,244 $ 185,829 International revenue by product type is as follows: 2021 2020 2019 Open ablation $ 23,206 $ 18,655 $ 24,945 Minimally invasive ablation 6,409 6,171 8,349 Appendage management 15,534 12,353 11,476 Total ablation and appendage management 45,149 37,179 44,770 Valve tools 49 108 208 Total international $ 45,198 $ 37,287 $ 44,978 The Company’s long-lived assets are located in the United States, except for $1,399 as of December 31, 2021 and $1,693 as of December 31, 2020 located primarily in Europe.

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure	SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS Additions Beginning Costs and Expenses Other (1) Deductions Ending Reserve for sales returns and allowances Year ended December 31, 2021 $ 1,889 $ 1,226 $ — $ 699 $ 2,416 Year ended December 31, 2020 3,979 66 — 2,156 1,889 Year ended December 31, 2019 1,410 369 2,240 40 3,979 Allowance for inventory valuation Year ended December 31, 2021 $ 1,779 $ 3,251 $ — $ 390 $ 4,640 Year ended December 31, 2020 1,517 801 — 539 1,779 Year ended December 31, 2019 1,029 848 — 360 1,517 Valuation allowance for deferred tax assets Year ended December 31, 2021 $ 117,025 $ 36,773 $ — $ — $ 153,798 Year ended December 31, 2020 101,178 15,847 — — 117,025 Year ended December 31, 2019 69,849 10,739 20,590 — 101,178 (1) In connection with the acquisition of SentreHEART, the Company recognized an allowance for sales returns and refunds for transition to ASC 606 to reflect SentreHEART’s historical refund practices and recorded a valuation allowance to offset the acquired net deferred tax assets.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [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 surgical treatments and therapies for atrial fibrillation (Afib), left atrial appendage (LAA) management and post-operative pain management and sells its products to medical centers globally through its direct sales force and distributors.
Principles of Consolidation	Principles of Consolidation— The Consolidated Financial Statements include the accounts of AtriCure, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Reclassification	Reclassification—During 2021, the Company changed the presentation of its consolidated statement of operations and comprehensive income (loss) to separately disclose the change in contingent consideration, previously reported in selling, general and administrative expenses. Amounts for comparative prior years have been reclassified to conform to the current period presentation. This reclassification had no impact on previously reported net loss or financial position.
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 financial institutions.
Investments	Investments— The Company invests primarily in 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 12 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 expected credit losses on 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 regulatory 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.
Property and Equipment	Property and Equipment— Property and equipment is stated at cost less accumulated depreciation. Depreciation is determined using the straight-line method over the estimated useful lives of assets (see Note 7). Maintenance and repair costs are expensed as incurred. The Company assesses the useful lives of property and equipment at least annually and retires assets no longer in use. 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 impairment has not been significant. The Company’s radiofrequency 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
Leases	Leases —The Company leases office, manufacturing and warehouse facilities and computer equipment under leases that qualify as either financing or operating leases, as determined at the inception of the lease arrangement. Lease assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make payments under the lease. Lease assets and liabilities are measured and recorded at the commencement date based on the present value of payments over the lease term. Lease assets and liabilities include lease incentives and options to extend or terminate when it is reasonably certain the Company will exercise that option. The Company uses the implicit rate when readily determinable; however, as most leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at measurement. The Company also 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 an option to extend the lease whose exercise is reasonably certain. 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 for the operating leases based on the terms of the underlying leases. Operating leases are included in operating lease right-of-use (ROU) assets and operating lease liabilities, while finance leases are included in property and equipment and finance lease liabilities. The short-term portions of both lease liabilities are included in other current liabilities and current maturities of debt and leases. Operating lease expense is recognized on a straight-line basis over the lease term. See Note 10 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 the 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 converted to a technology asset and amortized over its estimated useful life. Due to the nature of IPR&D projects, the Company may experience future delays or failures to obtain approvals or market clearances, or may discontinue or abandon the project, all of which may impact the estimated fair value of the IPR&D project. As a result, the Company may have a full or partial impairment charge related to the IPR&D, determined as the excess carrying value of the IPR&D asset 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 asset retirement obligations and other contractual obligations. The balance in prior periods also includes 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). The contingent consideration balance is included in noncurrent liabilities as any settlement is expected to be made primarily in shares of the Company’s common stock pursuant to the 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
Income Taxes	Income 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 a 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 by considering all available evidence. 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, taxable income in prior carryback years 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 for a valuation allowance. The Company's valuation allowance offsets 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.
Earnings Per Share	Earnings Per Share— Basic earnings per share is computed by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share reflects net income available to common stockholders divided by the weighted average number of common shares outstanding during the period and any dilutive common share equivalents, including shares issuable upon the vesting of restricted stock awards and restricted stock units, exercise of stock options as well as shares issuable under the Company's employee stock purchase plan (ESPP). Year Ended December 31, 2021 2020 2019 Net income (loss) available to common stockholders $ 50,199 $ (48,155) $ (35,194) Basic weighted average common shares outstanding 45,066 42,125 37,589 Effect of dilutive securities 973 — — Diluted weighted average common shares outstanding 46,039 42,125 37,589 Basic net income (loss) per common share $ 1.11 $ (1.14) $ (0.94) Diluted net income (loss) per common share $ 1.09 $ (1.14) $ (0.94)
Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)	Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)— In addition to net income (loss), the comprehensive income (loss) includes foreign currency translation adjustments and unrealized gains (losses) on investments.
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 and research of new and existing products or concepts, preclinical studies, clinical trials and related regulatory activities, as well as amortization of technology assets.
Advertising Costs	Advertising Costs — The Company expenses advertising costs as incurred. Advertising expense was $907, $655 and $635 during the years ended December 31, 2021, 2020 and 2019.
Share-Based Compensation	Share-Based Compensation— The Company recognizes share-based compensation expense for all share-based payment awards, including stock options, restricted stock awards, restricted stock units, performance share awards (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 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 several subjective assumptions, such as 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 target will be achieved and may adjust expense over the performance period based on changes to estimates of performance target achievement. If such targets are not met or service is not rendered for the requisite service period, no compensation cost is recognized, and any recognized compensation cost in prior periods 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 stock price, as defined by the award agreement, 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.
Use of Estimates	Use of Estimates— The preparation of the financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, including intangible assets, contingent assets and liabilities 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 Disclosures	Fair Value Disclosures —The Company classifies cash investments in U.S. government and agency obligations, accounts receivable, short-term other assets, accounts payable and accrued liabilities as Level 1. The carrying amounts of these assets and liabilities approximate their fair value due to their relatively short-term nature. Cash equivalents and investments in corporate bonds, repurchase agreements, 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. Significant unobservable inputs with respect to the fair value measurements of the Level 3 contingent consideration liabilities are developed using Company data. See Note 3 – Fair Value for further information on fair value measurements.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated other comprehensive (loss) income consisted of the following, net of tax: 2021 2020 2019 Total accumulated other comprehensive income (loss) at beginning of period $ 312 $ (158) $ (199) Unrealized gains (losses) on investments Balance at beginning of period $ 54 $ 100 $ (37) Other comprehensive (loss) income before reclassifications (941) (70) 137 Amounts reclassified from accumulated other comprehensive income (loss) to interest income — 24 — Balance at end of period $ (887) $ 54 $ 100 Foreign currency translation adjustment Balance at beginning of period $ 258 $ (258) $ (162) Other comprehensive (loss) income before reclassifications (768) 555 (277) Amounts reclassified from accumulated other comprehensive income (loss) to other income (expense) 449 (39) 181 Balance at end of period $ (61) $ 258 $ (258) Total accumulated other comprehensive (loss) income at end of period $ (948) $ 312 $ (158)
Schedule of Weighted Average Number of Shares	Year Ended December 31, 2021 2020 2019 Net income (loss) available to common stockholders $ 50,199 $ (48,155) $ (35,194) Basic weighted average common shares outstanding 45,066 42,125 37,589 Effect of dilutive securities 973 — — Diluted weighted average common shares outstanding 46,039 42,125 37,589 Basic net income (loss) per common share $ 1.11 $ (1.14) $ (0.94) Diluted net income (loss) per common share $ 1.09 $ (1.14) $ (0.94)

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [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 December 31, 2021: Quoted Prices Significant Significant Total Assets: Money market funds $ — $ 38,360 $ — $ 38,360 Commercial paper — 22,978 — 22,978 Government and agency obligations 32,690 — — 32,690 Corporate bonds — 95,845 — 95,845 Asset-backed securities — 28,261 — 28,261 Total assets $ 32,690 $ 185,444 $ — $ 218,134 Liabilities: Contingent consideration $ — $ — $ — $ — Total liabilities $ — $ — $ — $ — 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 Significant Significant Total Assets: Money market funds $ — $ 38,452 $ — $ 38,452 Commercial paper — 76,914 — 76,914 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 Using Significant Other Unobservable Inputs 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 for each of the years ended December 31: 2021 2020 2019 Beginning Balance – January 1 $ 184,800 $ 185,157 $ 18,773 Amounts acquired $ — $ — $ 171,300 Changes in fair value of contingent consideration (184,800) (357) (4,916) Ending Balance – December 31 $ — $ 184,800 $ 185,157

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Summary of Short-term Investments	Investments as of December 31, 2021 consisted of the following: Cost Basis Unrealized Fair Value Corporate bonds $ 96,408 $ (563) $ 95,845 Government and agency obligations 32,953 (263) 32,690 Commercial paper 22,978 — 22,978 Asset-backed securities 28,322 (61) 28,261 Total $ 180,661 $ (887) $ 179,774 Investments as of December 31, 2020 consisted of the following: Cost Basis Unrealized Fair Value Corporate bonds $ 73,702 $ 28 $ 73,730 Government and agency obligations 45,385 14 45,399 Commercial paper 76,914 — 76,914 Asset-backed securities 20,397 12 20,409 Total $ 216,398 $ 54 $ 216,452

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Company's Intangible Assets	The following table provides a summary of the Company’s intangible assets at December 31: 2021 2020 Estimated Useful Life Cost Accumulated Amortization Cost Accumulated Amortization Technology 5-15 years $ 55,712 $ 12,720 $ 11,691 $ 9,813 IPR&D — — 126,321 — Total $ 55,712 $ 12,720 $ 138,012 $ 9,813
Future Amortization Expense Related To Intangible Assets With Definite Lives	Future amortization expense is projected as follows: 2022 $ 3,653 2023 2,953 2024 2,953 2025 2,953 2026 2,953 2027 and thereafter 27,527 Total $ 42,992
Summary of Company's Goodwill	The following table provides a summary of the Company’s goodwill, which is not amortized, but rather tested annually for impairment: Net carrying amount as of December 31, 2019 $ 234,781 Additions — Net carrying amount as of December 31, 2020 234,781 Additions — Net carrying amount as of December 31, 2021 $ 234,781

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2021
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consisted of the following at December 31: 2021 2020 Raw materials $ 12,653 $ 11,966 Work in process 2,064 2,424 Finished goods 24,247 20,636 Inventories $ 38,964 $ 35,026

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following at December 31: Estimated Useful Life 2021 2020 Generators and related equipment 1 - 3 years $ 20,175 $ 18,669 Building under finance lease 15 years 14,250 14,250 Computer, software and office equipment 3 - 5 years 7,762 8,045 Machinery and equipment 3 - 7 years 8,501 6,697 Furniture and fixtures 3 - 7 years 5,877 5,849 Leasehold improvements 5 - 15 years 8,727 8,645 Construction in progress N/A 5,999 2,067 Land N/A 1,006 502 Equipment under finance leases 3 - 5 years 380 409 Total 72,677 65,133 Less accumulated depreciation (41,268) (36,843) Property and equipment, net $ 31,409 $ 28,290

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued liabilities consisted of the following at December 31: 2021 2020 Accrued compensation and employee-related expenses $ 30,990 $ 17,730 Sales returns and allowances 2,416 1,889 Accrued taxes and value-added taxes payable 1,452 1,256 Accrued royalties 754 703 Other accrued liabilities 470 406 Accrued legal settlement 10 6,000 Total $ 36,092 $ 27,984

Indebtedness (Tables)

Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Future Maturities on Debt	Future maturities of long-term debt, excluding the term loan final fee, are projected as follows: 2022 $ — 2023 3,333 2024 20,000 2025 20,000 2026 16,667 Total long-term debt, of which $60,000 is noncurrent $ 60,000

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Summary of Weighted Average Remaining Lease Term and Discount Rate	The weighted average remaining lease term and the discount rate for the reporting periods are as follows: As of As of As of December 31, 2021 December 31, 2020 December 31, 2019 Operating Leases Weighted average remaining lease term (years) 3.6 3.2 3.5 Weighted average discount rate 4.69 % 5.68 % 5.94 % Finance leases Weighted average remaining lease term (years) 8.6 9.7 11.0 Weighted average discount rate 6.91 % 6.91 % 7.05 %
Summary of Components of Lease Expense	The components of lease expense are as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Operating lease cost $ 1,052 $ 1,237 $ 952 Finance lease cost: Amortization of right-of-use assets 1,019 1,050 998 Interest on lease liabilities 792 844 872 Total finance lease cost $ 1,811 $ 1,894 $ 1,870
Summary of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was as follows: Year Ended Year Ended Year Ended December 31, 2021 December 31, 2020 December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 998 $ 1,236 $ 1,026 Operating cash flows for finance leases 620 844 872 Financing cash flows for finance leases 792 664 629 Right-of-use assets obtained in exchange for lease obligations: Operating Leases 3,752 1,421 1,884 Finance Leases — 22 270 Operating lease right-of-use asset obtained in business combination — — 2,929 Early termination of operating lease — 2,743 —
Summary of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases was as follows: As of December 31, 2021 As of December 31, 2020 Operating Leases Operating lease right-of-use assets $ 4,761 $ 1,914 Other current liabilities and current maturities of debt and leases 861 927 Operating lease liabilities 4,068 1,180 Total operating lease liabilities $ 4,929 $ 2,107 Finance Leases Property and equipment, at cost $ 14,607 $ 14,659 Accumulated depreciation (6,116) (5,247) Property and equipment, net $ 8,491 $ 9,412 Other current liabilities and current maturities of debt and leases $ 895 $ 823 Finance lease liabilities 10,082 10,969 Total finance lease liabilities $ 10,977 $ 11,792
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of December 31, 2021 were as follows: Operating Leases Finance Leases 2022 $ 861 $ 1,629 2023 1,160 1,652 2024 1,164 1,674 2025 920 1,625 2026 592 1,657 2027 and thereafter 868 6,515 Total payments $ 5,565 $ 14,752 Less imputed interest (636) (3,775) Total $ 4,929 $ 10,977

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Summary of Company's Provision for Income Taxes	The Company’s provision for income taxes for each of the years ended December 31 is as follows: 2021 2020 2019 Current Tax Expense Federal $ — $ (26) $ (26) State 42 78 34 Foreign 125 74 165 Total current tax expense 167 126 173 Deferred Tax Expense Federal $ (30,925) $ (10,304) $ (7,655) State (4,803) (1,686) (1,368) Foreign (826) (3,071) (1,690) Change in valuation allowance 36,575 15,049 10,739 Total deferred tax expense 21 (12) 26 Total tax expense $ 188 $ 114 $ 199
Summary of Detail of Deferred Tax Assets and Liabilities	The detail of deferred tax assets and liabilities at December 31 is as follows: 2021 2020 Deferred tax assets (liabilities): Net operating loss carryforwards $ 137,920 $ 123,556 Research and development credit carryforwards 11,269 9,365 Intangible assets (9,993) (30,773) Equity compensation 7,974 8,623 Finance and operating lease liabilities 3,700 3,164 Right-of-use assets (3,037) (2,547) Deferred interest 2,469 1,598 Inventories 2,434 1,360 Accruals and reserves 1,755 3,739 Property and equipment (1,264) (1,315) Other 587 293 Subtotal 153,814 117,063 Less valuation allowance (153,798) (117,025) Total $ 16 $ 38
Summary of Difference Between Effective Income Tax Rates and Federal Statutory Rate	The Company’s 2021, 2020 and 2019 effective income tax rates differ from the federal statutory rate as follows: 2021 2020 2019 Federal tax at statutory rate 21.0% $ 10,580 21.0% $ (10,088) 21.0% $ (6,950) Permanent differences (80.3)% (40,439) (2.5)% 1,214 1.2 % (386) Valuation allowance 72.6 % 36,575 (31.3) % 15,048 (32.4) % 10,739 State income taxes (9.4)% (4,760) 3.3% (1,607) 4.0 % (1,334) Federal R&D credit (3.7)% (1,878) 2.0% (985) 2.5% (837) Foreign income taxes 0.7% 344 4.5 % (2,140) (0.2) % 52 Federal deferred adjustments (0.5)% (234) 2.8 % (1,328) 3.3 % (1,085) Effective tax rate 0.4 % $ 188 (0.2) % $ 114 (0.6) % $ 199
Summary of Reconciliation of Change in Federal and State Unrecognized Tax Benefits	A reconciliation of the change in federal and state unrecognized tax benefits for 2021, 2020 and 2019 is presented below: 2021 2020 2019 Balance at the beginning of the year $ 1,798 $ 1,777 $ 1,157 Increases (decreases) for prior year tax positions — 21 620 Increases (decreases) for current year tax positions — — — Increases (decreases) related to settlements — — — Decreases related to statute lapse — — — Balance at the end of the year $ 1,798 $ 1,798 $ 1,777

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Activity Under Stock Based Compensation Plans	Activity under the plans during 2021 was as follows: Weighted Weighted Average Number of Average Remaining Aggregate Shares Exercise Contractual Intrinsic Time-Based Stock Options Outstanding Price Term Value Outstanding at January 1, 2021 904 $ 16.57 Granted 100 70.00 Exercised (333) 13.48 Cancelled (18) 46.76 Outstanding at December 31, 2021 653 $ 25.53 4.4 $ 29,071 Vested and expected to vest 647 $ 25.18 4.4 $ 29,023 Exercisable at December 31, 2021 520 $ 16.67 3.3 $ 27,513 Weighted Weighted RSA Average PSA Average Shares Grant Date Shares Grant Date Restricted Stock Awards and Performance Share Awards Outstanding Fair Value Outstanding Fair Value Outstanding at January 1, 2021 935 $ 30.92 287 $ 39.70 Awarded 306 67.51 99 89.36 Released (595) 28.73 (117) 38.51 Forfeited (18) 45.73 (42) 57.08 Outstanding at December 31, 2021 628 $ 50.96 227 $ 64.27 Weighted Weighted Average Number of Average Remaining Aggregate Shares Exercise Contractual Intrinsic Performance Stock Options Outstanding Price Term Value Outstanding at January 1, 2021 175 21.04 Granted — — Exercised (175) 21.04 Cancelled — — Outstanding at December 31, 2021 — $ — 0 $ — Exercisable at December 31, 2021 — $ — 0 $ —
Share-Based Compensation Expense Related to Employee Share-Based Compensation	The following table summarizes share-based compensation expense related to employees, directors and consultants for 2021, 2020 and 2019. The expense was allocated as follows: 2021 2020 2019 Cost of revenue $ 2,243 $ 1,425 $ 917 Research and development expenses 4,206 3,530 2,374 Selling, general and administrative expenses 21,629 17,687 14,686 Total $ 28,078 $ 22,642 $ 17,977 The expense by award type was allocated as follows: 2021 2020 2019 Restricted Stock Awards & Time-Based Stock Options $ 18,727 $ 18,612 $ 13,922 Performance Share Awards 8,095 2,921 3,254 ESPP 1,256 1,109 801 Total $ 28,078 $ 22,642 $ 17,977
Assumptions Used for Determining Fair Value of Options	The fair value of options is estimated on the grant date using the Black-Scholes model and includes the following assumptions: 2021 2020 2019 Range of risk-free interest rate 0.43-1.22% 0.30-1.73% 1.43 - 2.64% Range of expected life of stock options (years) 5.3 to 5.7 5.2 to 5.7 5.1 to 5.7 Range of expected volatility of stock 40.00 - 43.00% 40.00 - 43.00% 40.00 - 42.00% Weighted-average volatility 41.84% 41.54% 40.87% Dividend yield 0.00% 0.00% 0.00%
Schedule of Share-Based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions	The fair value of performance share awards with a market condition is estimated on the grant date using a Monte Carlo simulation and includes the following assumptions: 2021 Stock price $ 66.31 Expected term (years) 2.8 Company volatility 42.10% Peer group average volatility 91.00% Peer group average correlation 31.50% Risk-free interest rate 0.20% Dividend yield 0.00%
Weighted Average Estimated Grant Date Fair Value Per Share of Stock Options, Restricted Stock Granted, And Performance Awards	Based on the assumptions noted above, the weighted average estimated grant date fair value per share of the stock options, restricted stock awards and performance share awards granted for 2021, 2020 and 2019 was as follows: 2021 2020 2019 Stock options $ 27.31 $ 15.25 $ 11.56 Restricted stock awards 67.51 40.77 30.12 Performance share awards 89.36 38.42 30.77

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Summary of Revenue by Geographic Area	Revenue attributed to customer geographic locations is as follows: 2021 2020 2019 United States $ 229,131 $ 169,244 $ 185,829 Europe 27,931 23,217 27,929 Asia 16,077 13,118 15,976 Other international 1,190 952 1,073 Total international 45,198 37,287 44,978 Total revenue $ 274,329 $ 206,531 $ 230,807
Summary of Revenue by Product Type	United States revenue by product type is as follows: 2021 2020 2019 Open ablation $ 93,895 $ 75,399 $ 80,205 Minimally invasive ablation 39,380 25,647 34,842 Appendage management 94,568 66,981 68,166 Total ablation and appendage management 227,843 168,027 183,213 Valve tools 1,288 1,217 2,616 Total United States $ 229,131 $ 169,244 $ 185,829 International revenue by product type is as follows: 2021 2020 2019 Open ablation $ 23,206 $ 18,655 $ 24,945 Minimally invasive ablation 6,409 6,171 8,349 Appendage management 15,534 12,353 11,476 Total ablation and appendage management 45,149 37,179 44,770 Valve tools 49 108 208 Total international $ 45,198 $ 37,287 $ 44,978

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended	8 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 28, 2021
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment			$ 82,300,000	$ 0	$ 0
Options, restricted stock and performance based shares excluded from calculation of net loss per share			404,000	2,301,000	3,623,000
Advertising costs			$ 907,000	$ 655,000	$ 635,000
IPR&D | EPi-Sense
Finite-Lived Intangible Assets [Line Items]
Technology asset, gross						$ 44,021,000
Estimate useful life		15 years
IPR&D | aMAZE
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment	$ 82,300,000

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies (Weighted Average Common Shares Outstanding) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net income (loss) available to common stockholders	$ 50,199	$ (48,155)	$ (35,194)
Basic weighted average common shares outstanding (in shares)	45,066,000	42,125,000	37,589,000
Effect of dilutive securities	$ 973	$ 0	$ 0
Diluted weighted average common shares outstanding (in shares)	46,039,000	42,125,000	37,589,000
Basic net income (loss) per common share (in usd per share)	$ 1.11	$ (1.14)	$ (0.94)
Diluted net income (loss) per common share (in usd per share)	$ 1.09	$ (1.14)	$ (0.94)

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss) at beginning of period	$ 312	$ (158)	$ (199)
Total accumulated other comprehensive (loss) income at end of period	(948)	312	(158)
Unrealized gains (losses) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss) at beginning of period	54	100	(37)
Other comprehensive (loss) income before reclassifications	(941)	(70)	137
Amounts reclassified from accumulated other comprehensive (loss) income to other income (expense)	0	24	0
Total accumulated other comprehensive (loss) income at end of period	(887)	54	100
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss) at beginning of period	258	(258)	(162)
Other comprehensive (loss) income before reclassifications	(768)	555	(277)
Amounts reclassified from accumulated other comprehensive (loss) income to other income (expense)	449	(39)	181
Total accumulated other comprehensive (loss) income at end of period	$ (61)	$ 258	$ (258)

Fair Value (Financial Assets An

Fair Value (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Total assets	$ 218,134	$ 254,904
Liabilities:
Contingent consideration	0	184,800
Total liabilities	0	184,800
Money market funds
Assets:
Total assets	38,360	38,452
Commercial paper
Assets:
Total assets	22,978	76,914
Government and agency obligations
Assets:
Total assets	32,690	45,399
Corporate bonds
Assets:
Total assets	95,845	73,730
Asset-backed securities
Assets:
Total assets	28,261	20,409
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets	32,690	45,399
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets:
Total assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial paper
Assets:
Total assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government and agency obligations
Assets:
Total assets	32,690	45,399
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Assets:
Total assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Assets:
Total assets	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Total assets	185,444	209,505
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Significant Other Observable Inputs (Level 2) | Money market funds
Assets:
Total assets	38,360	38,452
Significant Other Observable Inputs (Level 2) | Commercial paper
Assets:
Total assets	22,978	76,914
Significant Other Observable Inputs (Level 2) | Government and agency obligations
Assets:
Total assets	0	0
Significant Other Observable Inputs (Level 2) | Corporate bonds
Assets:
Total assets	95,845	73,730
Significant Other Observable Inputs (Level 2) | Asset-backed securities
Assets:
Total assets	28,261	20,409
Significant Other Unobservable Inputs (Level 3)
Assets:
Total assets	0	0
Liabilities:
Contingent consideration	0	184,800
Total liabilities	0	184,800
Significant Other Unobservable Inputs (Level 3) | Money market funds
Assets:
Total assets	0	0
Significant Other Unobservable Inputs (Level 3) | Commercial paper
Assets:
Total assets	0	0
Significant Other Unobservable Inputs (Level 3) | Government and agency obligations
Assets:
Total assets	0	0
Significant Other Unobservable Inputs (Level 3) | Corporate bonds
Assets:
Total assets	0	0
Significant Other Unobservable Inputs (Level 3) | Asset-backed securities
Assets:
Total assets	$ 0	$ 0

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) shares in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2026	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Changes in levels or methodology		$ 0	$ 0
Change in fair value of contingent consideration (Note 3)		$ (184,800,000)	$ (357,000)	$ (4,916,000)
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of contingent consideration (Note 3)	$ 184,800,000
SentreHEART
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Shares issued or issuable		6,322
Total shares that may be issued		7,021
Shares issued at closing		699
Maximum contingent consideration payable		$ 260,000,000
Receiving PMA from FDA for LARIAT System
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Potential contingent consideration reduction, percentage		4.17%
Receiving PMA from FDA for LARIAT System | SentreHEART | Forecast
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Potential contingent consideration reduction if regulatory milestone not met						$ 0
Achievement of Interim Success Milestone
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments of contingent consideration		$ 25,000,000
American Medical Association Approval
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments of contingent consideration		$ 120,000,000
Potential contingent consideration reduction, percentage		4.17%
American Medical Association Approval | SentreHEART | Forecast
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Potential contingent consideration reduction if regulatory milestone not met					$ 0
Maximum | Receiving PMA from FDA for LARIAT System
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments of contingent consideration		$ 140,000,000

Fair Value (Level 3 Fair Value

Fair Value (Level 3 Fair Value Measurements Using Significant Other Unobservable Inputs For Acquisition-Related Contingent Consideration) (Details) - Significant Other Unobservable Inputs (Level 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance – January 1	$ 184,800	$ 185,157	$ 18,773
Amounts acquired	0	0	171,300
Changes in fair value of contingent consideration	(184,800)	(357)	(4,916)
Ending Balance – December 31	$ 0	$ 184,800	$ 185,157

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Gain (loss) on investments	$ 0	$ 0	$ 0

Investments (Summary Of Short-t

Investments (Summary Of Short-term Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary of Investment Holdings [Line Items]
Cost Basis	$ 180,661	$ 216,398
Unrealized Gains (Losses)	(887)	54
Fair Value	179,774	216,452
Corporate bonds
Summary of Investment Holdings [Line Items]
Cost Basis	96,408	73,702
Unrealized Gains (Losses)	(563)	28
Fair Value	95,845	73,730
Government and agency obligations
Summary of Investment Holdings [Line Items]
Cost Basis	32,953	45,385
Unrealized Gains (Losses)	(263)	14
Fair Value	32,690	45,399
Commercial paper
Summary of Investment Holdings [Line Items]
Cost Basis	22,978	76,914
Unrealized Gains (Losses)	0	0
Fair Value	22,978	76,914
Asset-backed securities
Summary of Investment Holdings [Line Items]
Cost Basis	28,322	20,397
Unrealized Gains (Losses)	(61)	12
Fair Value	$ 28,261	$ 20,409

Intangible Assets and Goodwil_2

Intangible Assets and Goodwill (Company's Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Cost	$ 55,712	$ 138,012
Accumulated Amortization	12,720	9,813
Technology
Finite-Lived Intangible Assets [Line Items]
Cost	55,712	11,691
Accumulated Amortization	12,720	9,813
IPR&D
Finite-Lived Intangible Assets [Line Items]
Cost	0	126,321
Accumulated Amortization	$ 0	$ 0
Minimum | Technology
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Maximum | Technology
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	15 years

Intangible Assets and Goodwil_3

Intangible Assets and Goodwill (Narrative) (Details) - USD ($)	3 Months Ended	8 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 28, 2021
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment			$ 82,300,000	$ 0	$ 0
Intangible assets, net		$ 42,992,000	42,992,000	128,199,000
Amortization of intangible assets			2,907,000	$ 1,682,000	$ 1,943,000
IPR&D | aMAZE
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment	$ 82,300,000
Intangible assets, net		$ 0	$ 0
IPR&D | EPi-Sense
Finite-Lived Intangible Assets [Line Items]
Technology asset, gross						$ 44,021,000
Estimate useful life		15 years

Intangible Assets and Goodwil_4

Intangible Assets and Goodwill (Future Amortization Expense Related To Intangible Assets With Definite Lives) (Details) $ in Thousands	Dec. 31, 2021USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 3,653
2023	2,953
2024	2,953
2025	2,953
2026	2,953
2027 and thereafter	27,527
Total	$ 42,992

Intangible Assets and Goodwil_5

Intangible Assets and Goodwill (Summary Of Company's Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance	$ 234,781	$ 234,781
Additions	0	0
Ending balance	$ 234,781	$ 234,781

Inventories (Summary Of Invento

Inventories (Summary Of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 12,653	$ 11,966
Work in process	2,064	2,424
Finished goods	24,247	20,636
Inventories	$ 38,964	$ 35,026

Property and Equipment (Summary

Property and Equipment (Summary Of Property And Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total	$ 72,677	$ 65,133
Less accumulated depreciation	(41,268)	(36,843)
Property and equipment, net	31,409	28,290
Generators and related equipment
Property, Plant and Equipment [Line Items]
Total	$ 20,175	18,669
Building under finance lease
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Total	$ 14,250	14,250
Computer, software and office equipment
Property, Plant and Equipment [Line Items]
Total	7,762	8,045
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total	8,501	6,697
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total	5,877	5,849
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total	8,727	8,645
Construction in progress
Property, Plant and Equipment [Line Items]
Total	5,999	2,067
Land
Property, Plant and Equipment [Line Items]
Total	1,006	502
Equipment under finance leases
Property, Plant and Equipment [Line Items]
Total	$ 380	$ 409
Minimum | Generators and related equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	1 year
Minimum | Computer, software and office equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Minimum | Equipment under finance leases
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum | Generators and related equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum | Computer, software and office equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Maximum | Equipment under finance leases
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years

Property and Equipment (Narrati

Property and Equipment (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Depreciation	$ 7,534	$ 7,866	$ 7,423
Generators and related equipment
Property, Plant and Equipment [Line Items]
Depreciation	2,327	2,503	$ 2,910
Net carrying value	$ 3,637	$ 3,410

Accrued Liabilities (Accrued Li

Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued compensation and employee-related expenses	$ 30,990	$ 17,730
Sales returns and allowances	2,416	1,889
Accrued taxes and value-added taxes payable	1,452	1,256
Accrued royalties	754	703
Other accrued liabilities	470	406
Accrued legal settlement	10	6,000
Total	$ 36,092	$ 27,984

Indebtedness (Narrative) (Detai

Indebtedness (Narrative) (Details) - USD ($)	Nov. 01, 2021	Sep. 01, 2021	Dec. 31, 2021
Line of Credit Facility [Line Items]
First required payment due		24 months
Amended loan payment deferral period	12 months
Silicon Valley Bank Agreement Effective 11/1/2021 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit, borrowings	$ 30,000,000
Commitment fee percentage			0.20%
Borrowing availability threshold			$ 30,000,000
Line of credit, amount outstanding			0
Line of credit, revolving line of credit			$ 28,750,000
Term Loan | Silicon Valley Bank Agreement Effective 11/1/2021
Line of Credit Facility [Line Items]
Loan amount	60,000,000
Expansion of borrowing capacity	$ 30,000,000
Debt instrument, term	5 years
Annual commitment fee, percentage			3.00%
Annual commitment fee			$ 60,000
Financing costs			$ 319,000
Term Loan | Silicon Valley Bank Agreement Effective 11/1/2021 | Prime Rate
Line of Credit Facility [Line Items]
Basis rate	1.25%

Indebtedness (Future Maturities

Indebtedness (Future Maturities On Debt) (Details)	Dec. 31, 2021USD ($)
Debt Disclosure [Abstract]
2022	$ 0
2023	3,333,000
2024	20,000,000
2025	20,000,000
2026	16,667,000
Total long-term debt, of which $60,000 is noncurrent	60,000,000
Long-term debt	$ 60,000,000

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Oct. 31, 2015
Minimum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	9 years
Letter of Credit | Mason Lease
Lessee, Lease, Description [Line Items]
Letter of credit outstanding		$ 1,250

Leases (Summary Of Weighted Ave

Leases (Summary Of Weighted Average Remaining Lease Term And Discount Rate) (Details)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
Weighted average remaining lease term (years)	3 years 7 months 6 days	3 years 2 months 12 days	3 years 6 months
Weighted average discount rate	4.69%	5.68%	5.94%
Finance leases
Weighted average remaining lease term (years)	8 years 7 months 6 days	9 years 8 months 12 days	11 years
Weighted average discount rate	6.91%	6.91%	7.05%

Leases (Summary Of Components O

Leases (Summary Of Components Of Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 1,052	$ 1,237	$ 952
Finance lease cost:
Amortization of right-of-use assets	1,019	1,050	998
Interest on lease liabilities	792	844	872
Total finance lease cost	$ 1,811	$ 1,894	$ 1,870

Leases (Summary Of Supplemental

Leases (Summary Of Supplemental Cash Flow Information Related To Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 998	$ 1,236	$ 1,026
Operating cash flows for finance leases	620	844	872
Financing cash flows for finance leases	792	664	629
Right-of-use assets obtained in exchange for lease obligations:
Operating Leases	3,752	1,421	1,884
Finance Leases	0	22	270
Operating lease right-of-use asset obtained in business combination	0	0	2,929
Early termination of operating lease	$ 0	$ 2,743	$ 0

Leases (Summary Of Supplement_2

Leases (Summary Of Supplemental Balance Sheet Information Related To Leases) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
Operating lease right-of-use assets	$ 4,761	$ 1,914
Other current liabilities and current maturities of debt and leases	861	927
Operating lease liabilities	4,068	1,180
Total operating lease liabilities	$ 4,929	$ 2,107
Operating lease, liability, current, statement of financial position [Extensible Enumeration]	Other current liabilities and current maturities of debt and leases	Other current liabilities and current maturities of debt and leases
Finance Leases
Property and equipment, at cost	$ 14,607	$ 14,659
Accumulated depreciation	(6,116)	(5,247)
Property and equipment, net	8,491	9,412
Other current liabilities and current maturities of debt and leases	895	823
Finance lease liabilities	10,082	10,969
Total finance lease liabilities	$ 10,977	$ 11,792
Finance lease, right-of-use asset, statement of financial position [Extensible Enumeration]	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Finance lease, liability, current, statement of financial position [Extensible Enumeration]	Other current liabilities and current maturities of debt and leases	Other current liabilities and current maturities of debt and leases

Leases (Schedule Of Maturities

Leases (Schedule Of Maturities Of Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2022	$ 861
2023	1,160
2024	1,164
2025	920
2026	592
2027 and thereafter	868
Total payments	5,565
Less imputed interest	(636)
Total	4,929	$ 2,107
Finance Leases
2022	1,629
2023	1,652
2024	1,674
2025	1,625
2026	1,657
2027 and thereafter	6,515
Total payments	14,752
Less imputed interest	(3,775)
Total	$ 10,977	$ 11,792

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies [Line Items]
Royalty expense		$ 3,124	$ 2,596	$ 2,892
Construction costs committed and outstanding		$ 3,800
Former nContact Stockholders
Commitments and Contingencies [Line Items]
Loss contingency payment	$ 6,000
Liability related settlement current			$ 6,000
Minimum
Commitments and Contingencies [Line Items]
Royalty rates		3.00%
Royalty agreement term		2025
Maximum
Commitments and Contingencies [Line Items]
Royalty rates		5.00%
Royalty agreement term		2023

Revenue (Narrative) (Details)

Revenue (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 274,329	$ 206,531	$ 230,807
Terms of sale for end-users	30 days
Terms of sale for distributors	60 days
Shipping and Handling
Disaggregation of Revenue [Line Items]
Revenue	$ 1,354	$ 1,192	$ 1,485

Income Taxes (Summary Of Compan

Income Taxes (Summary Of Company's Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current Tax Expense
Federal	$ 0	$ (26)	$ (26)
State	42	78	34
Foreign	125	74	165
Total current tax expense	167	126	173
Deferred Tax Expense
Federal	(30,925)	(10,304)	(7,655)
State	(4,803)	(1,686)	(1,368)
Foreign	(826)	(3,071)	(1,690)
Change in valuation allowance	36,575	15,049	10,739
Total deferred tax expense	21	(12)	26
Total tax expense	$ 188	$ 114	$ 199

Income Taxes (Summary Of Detail

Income Taxes (Summary Of Detail Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards
Net operating loss carryforwards	$ 137,920	$ 123,556
Research and development credit carryforwards	11,269	9,365
Intangible assets	(9,993)	(30,773)
Equity compensation	7,974	8,623
Finance and operating lease liabilities	3,700	3,164
Right-of-use assets	(3,037)	(2,547)
Deferred interest	2,469	1,598
Inventories	2,434	1,360
Accruals and reserves	1,755	3,739
Property and equipment	(1,264)	(1,315)
Other	587	293
Subtotal	153,814	117,063
Less valuation allowance	(153,798)	(117,025)
Total	$ 16	$ 38

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Research and development credit carryforwards	$ 11,269	$ 9,365
Pre-tax book loss for domestic operations	55,666	(43,218)	$ (28,002)
Pre-tax book loss for international operations	(5,279)	(4,823)	(6,993)
Undistributed earnings of foreign subsidiaries	290
Unrecognized tax benefits that would result in adjustments to other tax accounts	$ 1,798	$ 1,798	$ 1,777
Tax Year 2015
Income Tax Contingency [Line Items]
Open tax year	2018
Tax Year 2016
Income Tax Contingency [Line Items]
Open tax year	2017
Federal
Income Tax Contingency [Line Items]
Operating loss carryforward	$ 175,883
Research and development credit carryforwards	11,269
Federal | Tax Year 2021 And 2038
Income Tax Contingency [Line Items]
Operating loss carryforward	336,792
State
Income Tax Contingency [Line Items]
Operating loss carryforward	344,968
Foreign
Income Tax Contingency [Line Items]
Operating loss carryforward	$ 50,817
Minimum | Federal
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2022
Research and development credit carryforwards, expiration, year	2022
Minimum | State
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2022
Minimum | Foreign
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2022
Maximum | Federal
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2037
Research and development credit carryforwards, expiration, year	2041
Maximum | State
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2041
Maximum | Foreign
Income Tax Contingency [Line Items]
Operating loss carryforward, expiration year	2027

Income Taxes (Summary Of Differ

Income Taxes (Summary Of Difference Between Effective Income Tax Rates And Federal Statutory Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal tax at statutory rate, percent	21.00%	21.00%	21.00%
Federal tax at statutory rate	$ 10,580	$ (10,088)	$ (6,950)
Permanent differences and other, percent	(80.30%)	(2.50%)	1.20%
Permanent differences	$ (40,439)	$ 1,214	$ (386)
Valuation allowance, percent	72.60%	(31.30%)	(32.40%)
Valuation allowance	$ 36,575	$ 15,048	$ 10,739
State income taxes, percent	(9.40%)	3.30%	4.00%
State income taxes	$ (4,760)	$ (1,607)	$ (1,334)
Federal R&D credit, percent	(3.70%)	2.00%	2.50%
Federal R&D credit	$ (1,878)	$ (985)	$ (837)
Foreign tax rate differential, percent	0.70%	4.50%	(0.20%)
Foreign income taxes	$ 344	$ (2,140)	$ 52
Federal deferred adjustment, percent	(0.50%)	2.80%	3.30%
Federal deferred adjustments	$ (234)	$ (1,328)	$ (1,085)
Effective tax rate, percent	0.40%	(0.20%)	(0.60%)
Total tax expense	$ 188	$ 114	$ 199

Income Taxes (Summary Of Reconc

Income Taxes (Summary Of Reconciliation of Change In Federal And State Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at the beginning of the year	$ 1,798	$ 1,777	$ 1,157
Increases (decreases) for prior year tax positions	0	21	620
Increases (decreases) for current year tax positions	0	0	0
Increases (decreases) related to settlements	0	0	0
Decreases related to statute lapse	0	0	0
Balance at the end of the year	$ 1,798	$ 1,798	$ 1,777

Concentrations (Details)

Concentrations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)cUSTOMER	Dec. 31, 2020	Dec. 31, 2019
Concentration Risk [Line Items]
Number of customers | cUSTOMER	10
Cash and cash equivalents balance in excess of FDIC limits | $	$ 43,404
Customer Concentration Risk | Net Revenue | Medical Devices
Concentration Risk [Line Items]
Percentage representation of significant customer	10.50%	10.80%	12.00%
Customer Concentration Risk | Accounts Receivable | Medical Devices
Concentration Risk [Line Items]
Percentage representation of significant customer	16.00%	13.00%

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Postemployment Benefits [Abstract]
Employee contribution percent	50.00%	50.00%	50.00%
Maximum percentage of employee contribution to the plan	6.00%	6.00%	6.00%
Company's matching contribution	$ 2,651,000	$ 2,237,000	$ 1,915,000
Discretionary contributions made	0	0	0
Total contributions to retirement plan	$ 349,000	$ 244,000	$ 248,000

Equity Compensation Plans (Narr

Equity Compensation Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shareholder return period	20 days
Total intrinsic value of options exercised	$ 27,318,000	$ 29,594,000	$ 1,985,000
Tax benefit recognized	0	0	0
Proceeds from stock option exercises	8,175,000	10,835,000	1,202,000
Incremental compensation expenses	$ 2,856,000	569,000
Time-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiry of options from the date of grant	10 years
Stock options compensation costs	$ 2,341,000
Weighted average period of recognizing cost	2 years 2 months 12 days
Restricted Stock Awards and Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted stock vested	$ 40,510,000	34,200,000	$ 23,479,000
Unrecognized compensation costs related to non-vested performance options	$ 19,346,000
Weighted average period of recognizing cost	1 year 9 months 18 days
Performance Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares options vest in	25,000
Period of considering closing price of common stock	30 days
Total fair value of restricted stock vested	$ 8,165,000	$ 4,003,000
Unrecognized compensation costs related to non-vested performance options	$ 10,301,000
Weighted average period of recognizing cost	1 year 9 months 18 days
Stock Options and Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested share-based compensation arrangements with performance shares	$ 21,687,000
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance	12,899,000
Shares available for future grants	1,505,000
2014 Plan | Time-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2014 Plan | Performance Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting right of shares of common stock	1
2008 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's common stock may be purchased at a discount	15.00%
Offering period	6 months
Participants purchase limit value	$ 25,000
Description of participants purchase limit	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.
Shares available for future issuance under the ESPP	305,000
2018 PSAs | Minimum | Performance Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance stock award threshold, target and maximum payout opportunity percentage		0.00%
2018 PSAs | Maximum | Performance Stock Options
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%
First, Second, And Third Anniversaries | Stock Options, RSA's, and RSU's
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage	33.30%

Equity Compensation Plans (Acti

Equity Compensation Plans (Activity Under Stock Based Compensation Plans) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Time-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of shares outstanding, shares	904,000
Beginning balance, weighted average exercise price, usd per share	$ 16.57
Granted, number of shares outstanding, shares	100,000
Granted, weighted average exercise price, usd per share	$ 70
Exercised, number of shares outstanding, shares	(333,000)
Exercised, weighted average exercise price, usd per share	$ 13.48
Cancelled, number of shares outstanding, shares	(18,000)
Cancelled, weighted average exercise price, usd per share	$ 46.76
Ending balance, number of shares outstanding, shares	653,000	904,000
Ending balance, weighted average exercise price, usd per share	$ 25.53	$ 16.57
Vested and expected to vest, number of shares outstanding, shares	647,000
Vested and expected to vest, weighted average exercise price, usd per share	$ 25.18
Exercisable, ending balance, number of shares outstanding, shares	520,000
Exercisable, ending balance, weighted average exercise price, usd per share	$ 16.67
Outstanding, ending balance, weighted average remaining contractual term	4 years 4 months 24 days
Vested and expected to vest, ending balance, weighted average remaining contractual term	4 years 4 months 24 days
Exercisable, ending balance, ending balance, weighted average remaining contractual term	3 years 3 months 18 days
Outstanding, ending balance, aggregate intrinsic value, stock options	$ 29,071
Vested and expected to vest, aggregate intrinsic value, stock options	29,023
Exercisable, ending balance, aggregate intrinsic value, stock options	$ 27,513
Restricted Stock Awards and Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of shares outstanding	935,000
Awarded, number of shares outstanding	306,000
Released, number of shares outstanding	(595,000)
Forfeited, number of shares outstanding	(18,000)
Ending balance, number of shares outstanding	628,000	935,000
Beginning balance, weighted average grant date fair value	$ 30.92
Awarded, weighted average grant date fair value	67.51	$ 40.77	$ 30.12
Released, weighted average grant date fair value	28.73
Forfeited, weighted average grant date fair value	45.73
Ending balance, weighted average grant date fair value	$ 50.96	$ 30.92
Restricted Stock Awards and Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of shares outstanding	287,000
Awarded, number of shares outstanding	99,000
Released, number of shares outstanding	(117,000)
Forfeited, number of shares outstanding	(42,000)
Ending balance, number of shares outstanding	227,000	287,000
Beginning balance, weighted average grant date fair value	$ 39.70
Awarded, weighted average grant date fair value	89.36	$ 38.42	$ 30.77
Released, weighted average grant date fair value	38.51
Forfeited, weighted average grant date fair value	57.08
Ending balance, weighted average grant date fair value	$ 64.27	$ 39.70
Performance Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of shares outstanding, shares	175,000
Beginning balance, weighted average exercise price, usd per share	$ 21.04
Granted, number of shares outstanding, shares	0
Granted, weighted average exercise price, usd per share	$ 0
Exercised, number of shares outstanding, shares	(175,000)
Exercised, weighted average exercise price, usd per share	$ 21.04
Cancelled, number of shares outstanding, shares	0
Cancelled, weighted average exercise price, usd per share	$ 0
Ending balance, number of shares outstanding, shares	0	175,000
Ending balance, weighted average exercise price, usd per share	$ 0	$ 21.04
Exercisable, ending balance, number of shares outstanding, shares	0
Exercisable, ending balance, weighted average exercise price, usd per share	$ 0
Outstanding, ending balance, weighted average remaining contractual term	0 years
Exercisable, ending balance, ending balance, weighted average remaining contractual term	0 years
Outstanding, ending balance, aggregate intrinsic value, stock options	$ 0
Exercisable, ending balance, aggregate intrinsic value, stock options	$ 0

Equity Compensation Plans (Shar

Equity Compensation Plans (Share-Based Compensation Expense Related To Employee Share-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	$ 28,078	$ 22,642	$ 17,977
Restricted Stock Awards & Time-Based Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	18,727	18,612	13,922
Performance Share Awards
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	8,095	2,921	3,254
ESPP
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	1,256	1,109	801
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	2,243	1,425	917
Research and development expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	4,206	3,530	2,374
Selling, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	$ 21,629	$ 17,687	$ 14,686

Equity Compensation Plans (Assu

Equity Compensation Plans (Assumptions Used For Determining Fair Value Of Options) (Details) - Time-Based Stock Options	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average volatility	41.84%	41.54%	40.87%
Dividend yield	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of risk-free interest rate	0.43%	0.30%	1.43%
Range of expected life of stock options (years)	5 years 3 months 18 days	5 years 2 months 12 days	5 years 1 month 6 days
Range of expected volatility of stock	40.00%	40.00%	40.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of risk-free interest rate	1.22%	1.73%	2.64%
Range of expected life of stock options (years)	5 years 8 months 12 days	5 years 8 months 12 days	5 years 8 months 12 days
Range of expected volatility of stock	43.00%	43.00%	42.00%

Equity Compensation Plans (As_2

Equity Compensation Plans (Assumptions Used For Determining Fair Value Of Stock) (Details) - Performance Stock Options	12 Months Ended
	Dec. 31, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	$ 66.31
Expected term (years)	2 years 9 months 18 days
Company volatility	42.10%
Peer group average volatility	91.00%
Peer group average correlation	0.3150
Risk-free interest rate	0.20%
Dividend yield	0.00%

Equity Compensation Plans (Weig

Equity Compensation Plans (Weighted Average Estimated Grant Date Fair Value Per Share Of Stock Options, Restricted Stock Granted, And Performance Awards) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average estimated grant date fair value per share of the stock options granted	$ 27.31	$ 15.25	$ 11.56
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average estimated grant date fair value per share of the restricted stock granted	67.51	40.77	30.12
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average estimated grant date fair value per share of the restricted stock granted	$ 89.36	$ 38.42	$ 30.77

Segment and Geographic Inform_3

Segment and Geographic Information (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Europe
Long-lived assets	$ 1,399	$ 1,693

Segment and Geographic Inform_4

Segment and Geographic Information (Revenue By Geographic Area) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 274,329	$ 206,531	$ 230,807
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	229,131	169,244	185,829
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	27,931	23,217	27,929
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	16,077	13,118	15,976
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,190	952	1,073
Total international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 45,198	$ 37,287	$ 44,978

Segment and Geographic Inform_5

Segment and Geographic Information (Revenue By Product Type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Revenue	$ 274,329	$ 206,531	$ 230,807
United States
Revenue from External Customer [Line Items]
Revenue	229,131	169,244	185,829
United States | Open ablation
Revenue from External Customer [Line Items]
Revenue	93,895	75,399	80,205
United States | Minimally invasive ablation
Revenue from External Customer [Line Items]
Revenue	39,380	25,647	34,842
United States | Appendage management
Revenue from External Customer [Line Items]
Revenue	94,568	66,981	68,166
United States | Total ablation and appendage management
Revenue from External Customer [Line Items]
Revenue	227,843	168,027	183,213
United States | Valve tools
Revenue from External Customer [Line Items]
Revenue	1,288	1,217	2,616
Total international
Revenue from External Customer [Line Items]
Revenue	45,198	37,287	44,978
Total international | Open ablation
Revenue from External Customer [Line Items]
Revenue	23,206	18,655	24,945
Total international | Minimally invasive ablation
Revenue from External Customer [Line Items]
Revenue	6,409	6,171	8,349
Total international | Appendage management
Revenue from External Customer [Line Items]
Revenue	15,534	12,353	11,476
Total international | Total ablation and appendage management
Revenue from External Customer [Line Items]
Revenue	45,149	37,179	44,770
Total international | Valve tools
Revenue from External Customer [Line Items]
Revenue	$ 49	$ 108	$ 208

Schedule II (Schedule Of Valuat

Schedule II (Schedule Of Valuation And Qualifying Accounts) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Reserve For Sales Returns And Allowances [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 1,889,000	$ 3,979,000		$ 1,410,000
Additions	1,226,000	66,000		369,000
Other	0	0	[1]	2,240,000
Deductions	699,000	2,156,000		40,000
Ending Balance	2,416,000	1,889,000		3,979,000
Allowance For Inventory Valuation [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	1,779,000	1,517,000		1,029,000
Additions	3,251,000	801,000		848,000
Other	0	0		0
Deductions	390,000	539,000		360,000
Ending Balance	4,640,000	1,779,000		1,517,000
Valuation Allowance For Deferred Tax Assets [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	117,025,000	101,178,000		69,849,000
Additions	36,773,000	15,847,000		10,739,000
Other	0	0	[1]	20,590,000
Deductions	0	0		0
Ending Balance	$ 153,798,000	$ 117,025,000		$ 101,178,000
[1]	In connection with the acquisition of SentreHEART, the Company recognized an allowance for sales returns and refunds for transition to ASC 606 to reflect SentreHEART’s historical refund practices and recorded a valuation allowance to offset the acquired net deferred tax assets.