Vericel (VCEL) 10-K 24 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 15, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35280
Entity Registrant Name	VERICEL CORPORATION
Entity Incorporation, State or Country Code	MI
Entity Tax Identification Number	94-3096597
Entity Address, Address Line One	64 Sidney Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	588-5555
Title of 12(b) Security	Common Stock (No par value)
Trading Symbol	VCEL
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			$ 617,742,709
Entity Common Stock, Shares Outstanding		45,954,992
Documents Incorporated by Reference	Document Form 10-K Reference Proxy Statement for the Annual Meeting of Shareholders scheduled for April 28, 2021 Items 10, 11, 12, 13 and 14 of Part III
Entity Central Index Key	0000887359
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 33,620	$ 26,889
Short-term investments	42,187	42,829
Accounts receivable (net of allowance for doubtful accounts of $143 and $306, respectively)	34,504	32,168
Inventory	9,356	6,816
Other current assets	3,893	2,953
Total current assets	123,560	111,655
Property and equipment, net	7,633	7,144
Restricted cash	211	89
Right-of-use assets	50,105	25,103
Long-term investments	24,099	9,247
Total assets	205,608	153,238
Current liabilities:
Accounts payable	6,755	6,345
Accrued expenses	11,293	7,948
Current portion of operating lease liabilities	4,394	5,461
Other liabilities	41	41
Total current liabilities	22,483	19,795
Operating lease liabilities	48,789	22,242
Other long-term liabilities	76	110
Total liabilities	71,348	42,147
COMMITMENTS AND CONTINGENCIES
Shareholders’ equity:
Common stock, no par value; shares authorized — 75,000; shares issued and outstanding — 45,804 and 44,864, respectively	510,061	489,749
Accumulated other comprehensive income	14	21
Accumulated deficit	(375,815)	(378,679)
Total shareholders’ equity	134,260	111,091
Total liabilities and shareholders’ equity	$ 205,608	$ 153,238

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 143	$ 306
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	45,804,000	44,864,000
Common stock, shares outstanding (in shares)	45,804,000	44,864,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Product sales, net	$ 121,968	$ 117,850	$ 90,857
Other revenue	2,211	0	0
Total revenue	124,179	117,850	90,857
Cost of product sales	39,951	37,571	32,160
Gross profit	84,228	80,279	58,697
Research and development	13,020	30,391	13,599
Selling, general and administrative	68,836	61,139	49,007
Total operating expenses	81,856	91,530	62,606
Income (loss) from operations	2,372	(11,251)	(3,909)
Other income (expense):
Increase in fair value of warrants	0	0	(2,524)
Loss on extinguishment of debt	0	0	(838)
Interest income	691	1,614	897
Interest expense	(6)	(8)	(1,732)
Other expense	(13)	(20)	(31)
Total other income (expense)	672	1,586	(4,228)
Net income (loss) before tax provision	3,044	(9,665)	(8,137)
Tax provision	180	0	0
Net income (loss)	$ 2,864	$ (9,665)	$ (8,137)
Net income (loss) per share attributable to common shareholders (basic) (in USD per share)	$ 0.06	$ (0.22)	$ (0.20)
Weighted average common shares outstanding (basic) (in shares)	45,221	44,180	40,242
Net income (loss) per share attributable to common shareholders (diluted) (in USD per share)	$ 0.06	$ (0.22)	$ (0.20)
Weighted average common shares outstanding (diluted) (in shares)	47,282	44,180	40,242
Revenue, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,864	$ (9,665)	$ (8,137)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	(7)	60	(39)
Comprehensive income (loss)	$ 2,857	$ (9,605)	$ (8,176)

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Warrants	Accumulated Other Comprehensive Gain (loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2017		35,861,000
Beginning balance at Dec. 31, 2017	$ 22,540	$ 383,020	$ 397	$ 0	$ (360,877)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	(8,137)				(8,137)
Compensation expense related to stock options granted, net of forfeitures	7,223	$ 7,223
Issuance of common stock, net of issuance costs (in shares)		5,750,000
Issuance of common stock, net of issuance costs	70,028	$ 70,028
Stock option exercises (in shares)		1,180,000
Stock option exercises	3,705	$ 3,705
Shares issued under the Employee Stock Purchase Plan (in shares)		106,000
Shares issued under the Employee Stock Purchase Plan	656	$ 656
Exercise of warrants resulting in issuance of common stock (in shares)		681,000
Exercise of warrants resulting in issuance of common stock	6,255	$ 6,548	(293)
Unrealized (gain) loss on investments	(39)			(39)
Ending balance (in shares) at Dec. 31, 2018		43,578,000
Ending balance at Dec. 31, 2018	102,231	$ 471,180	104	(39)	(369,014)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	(9,665)				(9,665)
Compensation expense related to stock options granted, net of forfeitures	13,179	$ 13,179
Stock option exercises (in shares)		1,197,000
Stock option exercises	4,354	$ 4,354
Shares issued under the Employee Stock Purchase Plan (in shares)		69,000
Shares issued under the Employee Stock Purchase Plan	932	$ 932
Exercise of warrants resulting in issuance of common stock (in shares)		20,000
Exercise of warrants resulting in issuance of common stock	0	$ 104	(104)
Unrealized (gain) loss on investments	60			60
Ending balance (in shares) at Dec. 31, 2019		44,864,000
Ending balance at Dec. 31, 2019	111,091	$ 489,749	0	21	(378,679)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	2,864				2,864
Compensation expense related to stock options granted, net of forfeitures	$ 13,843	$ 13,843
Stock option exercises (in shares)	790,532	790,000
Stock option exercises	$ 5,582	$ 5,582
Shares issued under the Employee Stock Purchase Plan (in shares)		117,000
Shares issued under the Employee Stock Purchase Plan	1,050	$ 1,050
Issuance of stock for restricted stock units vesting (shares)		47,000
Restricted stock withheld for employee taxes (in shares)		(14,000)
Restricted stock withheld for employee taxes	(163)	$ (163)
Unrealized (gain) loss on investments	(7)			(7)
Ending balance (in shares) at Dec. 31, 2020		45,804,000
Ending balance at Dec. 31, 2020	$ 134,260	$ 510,061	$ 0	$ 14	$ (375,815)

CONSOLIDATED STATEMENTS OF SH_2

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical)	12 Months Ended
	Dec. 31, 2018USD ($)
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 4,700,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income (loss)	$ 2,864	$ (9,665)	$ (8,137)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation and amortization	2,383	1,744	1,426
Stock compensation expense	13,843	13,179	7,223
Change in fair value of warrants	0	0	2,524
Loss on extinguishment of debt	0	0	838
Foreign currency translation loss	63	42	51
Loss on sale of fixed assets	30	0	22
Amortization of premiums and discounts on marketable securities	318	(610)	(327)
Non-cash lease cost	4,445	2,787	0
Changes in operating assets and liabilities:
Inventory	(2,540)	(3,258)	235
Accounts receivable	(2,336)	(8,714)	(5,184)
Other current assets	(940)	(106)	(1,267)
Accounts payable	33	(1,024)	899
Accrued expenses	3,345	1,018	1,493
Operating lease liabilities	(3,951)	(2,512)
Other non-current assets and liabilities, net	15	(64)	(208)
Net cash provided by (used for) operating activities	17,572	(7,183)	(412)
Investing activities:
Purchases of investments	(63,057)	(72,346)	(66,549)
Sales and maturities of investments	48,523	85,577	2,200
Expenditures for property, plant and equipment	(2,626)	(2,616)	(2,678)
Net cash provided by (used for) investing activities	(17,160)	10,615	(67,027)
Financing activities:
Net proceeds from equity offering	0	0	70,028
Net proceeds from common stock issuance due to stock option exercises	6,632	5,286	4,361
Proceeds from exercise of warrants	0	0	2,716
Payments on long-term debt	0	0	(17,532)
Fee on long-term debt	0	0	(710)
Other	(191)	(26)	0
Net cash provided by financing activities	6,441	5,260	58,863
Net increase (decrease) in cash, cash equivalents, and restricted cash	6,853	8,692	(8,576)
Cash, cash equivalents, and restricted cash at beginning of period	26,978	18,286	26,862
Cash, cash equivalents, and restricted cash at end of period	$ 33,831	$ 26,978	$ 18,286

Organization

Organization	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Vericel Corporation, a Michigan corporation (together with its consolidated subsidiaries referred to herein as the Company, or Vericel), was incorporated in March 1989 and began employee-based operations in 1991. The Company is a fully-integrated, commercial-stage biopharmaceutical company and is a leader in advanced therapies for the sports medicine and severe burn care markets. Vericel currently markets two cell therapy products in the United States, MACI ® and Epicel ® . MACI (autologous cultured chondrocytes on porcine collagen membrane) is an autologous cellularized scaffold product indicated for the repair of symptomatic, single or multiple full-thickness cartilage defects of the knee with or without bone involvement in adults. Epicel (cultured epidermal autografts) is a permanent skin replacement for the treatment of adult and pediatric patients with deep-dermal or full-thickness burns comprising greater than or equal to 30 percent of total body surface area (TBSA). The Company also holds an exclusive license from MediWound Ltd. (MediWound) for North American rights to NexoBrid ® , a registration-stage biological orphan product for debridement of severe thermal burns. The Company operates its business primarily in the U.S. in one reportable segment — the research, product development, manufacture and distribution of cellular therapies for use in the treatment of specific diseases. COVID-19 Throughout 2020, the pandemic caused by the spread of a novel strain of coronavirus (COVID-19) has created significant disruptions to the U.S. and global economy and has contributed to significant volatility in financial markets. The global impact of the outbreak is continually evolving and, as the virus spreads and infection rates surge in various locations, many state, local and national governments – including those in Massachusetts and Michigan, where the Company's operations are located – have responded by issuing, extending and supplementing orders requiring quarantines, restrictions on travel, and the mandatory closure of certain non-essential businesses, among other actions. In the U.S., the status and application of these orders have varied on a state-by-state basis since the early days of the pandemic. Many of the restrictions have been periodically updated as infections rates in the U.S. have risen and fallen and as world health leaders learn more about the virus, its transmission pathway and who is most at risk. Because Vericel is deemed an essential business, the Company has been exempted from government orders requiring the closure of workplaces and the cessation of business operations, as they have existed from time-to-time during the pandemic. Notwithstanding being an essential business, the Company’s business and operations have been adversely impacted by the effects of COVID-19. In mid-March, the American College of Surgeons and United States Surgeon General recommended that each hospital, health system, and surgeon minimize, postpone, or cancel electively scheduled surgeries. These recommendations were followed by numerous state level executive orders either restricting or partially restricting elective surgeries. Because MACI is an elective surgical procedure, as a result of these restrictions, beginning in mid-March 2020, the Company began to experience a significant increase in cancellations of scheduled MACI procedures as well as a slowdown in new MACI orders. The widespread suspension of elective procedures impacted the Company’s business and operations during the first and second quarters of 2020. These restrictions began to ease in May and, by the end of September 2020, there were no state orders in place that directly impacted a surgeon’s or patient’s ability to move forward with a MACI surgery. However, in late September and October 2020, the number of COVID-19 infections began to increase markedly in various geographies and by late December 2020 the rolling seven-day average of new daily coronavirus cases in the United States reached the highest level at any point during the pandemic. Because Epicel is used almost exclusively in the emergent setting by burn centers and surgeons throughout the country, Epicel revenue and procedure volumes have been less affected by the pandemic. Although hospitals are now better prepared for a subsequent surge in COVID-19 patients, the risk remains that regional or local restrictions could again be placed on the performance of elective surgical procedures if the number of COVID-19 infections in the United States continues to rise. At the outset of the pandemic, the Company put in place a comprehensive workplace protection plan, which institutes protective measures in response to COVID-19. These measures include mandatory employee training on social distancing and hygiene protocols, conducting daily health screenings of all employees, vendors and visitors entering our facilities, canceling all international business travel, limiting domestic business travel to essential purposes, requesting that employees limit non-essential personal travel, enhancing our facilities’ janitorial and sanitary procedures, making certain physical modifications and enhancements to our facilities to enable effective social distancing among employees, providing certain personal protective equipment to employees working in our offices, encouraging employees to work from home to the extent their job function enables them to do so, limiting third-party access to the Company’s facilities, encouraging the use of virtual employee meetings, modifying the manner and schedule of on-site production activities, and providing guidance to our field-based commercial teams concerning their communications and contact with customers and healthcare professionals. In addition, we put certain expense reduction measures in place including a reduction of discretionary spending. The Company is reviewing these measures regularly as the pandemic evolves and may take additional actions to the extent required. The accompanying Consolidated Financial Statements have been prepared on a basis which assumes that the Company will continue as a going concern and contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. As of December 31, 2020, the Company had an accumulated deficit of $375.8 million and had net income of $2.9 million for the year ended December 31, 2020. The Company had cash and cash equivalents of $33.6 million and investments of $66.3 million as of December 31, 2020. The Company expects that cash from the sales of our products and existing cash, cash equivalents and investments will be sufficient to support the Company’s current operations through at least 12 months from the issuance of the Consolidated Financial Statements. However, the effects of the COVID-19 pandemic continue to evolve and may result in irrecoverable losses of customers and significantly impact long-term liquidity requiring the Company to engage in layoffs, furloughs and/or reductions in salaries. To the extent the United States experiences a resurgence in COVID-19 infections and elective surgery restrictions are reinstated on a widespread basis and significantly impact the Company’s business, the Company may need to access additional capital; however, the Company may not be able to obtain financing on acceptable terms or at all, particularly in light of the impact of COVID-19 on the global economy and financial markets. The terms of any financing may adversely affect the holdings or the rights of the Company’s shareholders.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The Consolidated Financial Statements include the accounts of Vericel and its wholly-owned subsidiaries, Vericel Denmark ApS, in Kastrup, Demark and Vericel Security Corporation (collectively, the Company). All inter-company transactions and accounts have been eliminated in consolidation. Vericel Denmark ApS ceased operations in 2015. Use of Estimates The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of expenses during the reported period. The Company is monitoring the potential impact of the COVID-19 pandemic on its business and financial statements. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments reflected in these financial statements or a revision of the carrying value of its assets or liabilities as of the issuance of these financial statements. These estimates may change as new events occur and additional information is obtained. Actual results could differ from those estimates. Consolidated Statement of Cash Flows The following table presents certain supplementary cash flows information for the years ended December 31, 2020, 2019 and 2018: Year Ended December 31, (In thousands) 2020 2019 2018 Supplementary Cash Flows information: Non-cash information: Warrants exercised for common stock $ — $ 104 $ 3,538 Right-of-use asset and lease liability recognized 29,573 2,599 — Additions to property and equipment included in accounts payable 531 217 606 Cash information: Interest paid (net of interest capitalized) $ 6 $ 8 $ 2,230 Year Ended December 31, (In thousands) 2020 2019 2018 Reconciliation of cash, cash equivalents, and restricted cash reported in the statement of financial position: Cash and cash equivalents $ 33,620 $ 26,889 $ 18,286 Restricted cash, included in other long-term assets 211 89 — Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 33,831 $ 26,978 $ 18,286 Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase and consist primarily of demand deposits, money market funds, overnight repurchase agreements and short duration agency bonds and commercial paper. Restricted cash Amounts included in restricted cash represent those required to be set aside to meet contractual terms of a lease agreement held by the Company. Investments Investments classified as short-term have maturities of less than one year. Investments classified as long-term are those that: (i) have a maturity of greater than one year, and (ii) we do not intend to liquidate within the next twelve months, although these funds are available for use and, therefore, are classified as available-for-sale. The Company’s investment strategy is to buy short-duration marketable securities with a high credit rating. As of December 31, 2020 and 2019, all marketable securities held by the Company had remaining contractual maturities of three years or less. Unrealized gains are included as a component of accumulated other comprehensive income in the consolidated balance sheets and statements of stockholders’ equity and a component of total comprehensive income (loss) in the consolidated statements of comprehensive income (loss), until realized. Unrealized losses are evaluated for impairment under ASC 326, Financial Instruments - Credit Losses , to determine if the impairment is credit-related or non credit-related. Credit-related impairment is recognized as an allowance on the balance sheet with a corresponding adjustment to earnings, and non credit-related impairment is recognized in other comprehensive income (loss), net of taxes. Inventory Inventories are measured at the lower of cost or net realizable value. Cost is calculated based upon standard-cost which approximates costs determined on the first-in, first-out method. The Company periodically reviews its inventories for excess or obsolescence and writes down obsolete or other unmarketable inventory to its estimated net realizable value. If the actual net realizable value is less than that estimated by the Company, or if it is determined that inventory utilization will further diminish based on estimates of demand, additional inventory write-downs may be required. In all cases, product inventory is carried at the lower of cost or its estimated net realizable value. Amounts written down are charged to cost of sales. Leases The Company adopted the new leasing standards using the modified retrospective transition approach, as of January 1, 2019, with no restatement of prior periods. Upon adoption all operating lease commitments with a lease term greater than 12 months that were previously assessed under the prior lease guidance, were recognized as right-of-use assets and liabilities, on a discounted basis on the balance sheet. Leases with an initial term of 12 months or less are not recorded on the balance sheet. Certain lease agreements include rental payments that are adjusted periodically for inflation or other variables. The leases are initially measured using the projected payments adjusted for the index or rate in effect at the commencement date. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance and other expenses, which are generally referred to as non-lease components. Variable non-lease components are not measured as part of the right-of-use asset and liability. Only when lease components and their associated non-lease components are fixed are they accounted for as a single lease component and are recognized as part of a right-of-use asset and liability. Some leases contain clauses for renewal at the Company’s option with renewal terms that generally extend the lease term from 1 to 5 years. Certain lease agreements contain options to purchase the leased property and options to terminate the lease. Payments to be made in option periods are recognized as part of the right-of-use lease assets and lease liabilities when it is reasonably certain that the option to extend the lease will be exercised or the option to terminate the lease will not be exercised, or is not at the Company’s option. The Company determines whether the reasonably certain threshold is met by considering contract-, asset-, market-, and entity-based factors. A portfolio approach is applied to certain lease contracts with similar characteristics. The Company’s lease agreements do not contain any significant residual value guarantees or material restrictive covenants imposed by the leases. Accounts Receivable Accounts receivable are initially recorded at the contractual amount owed by the customer or based on expected payments from the insurance provider, hospital or patient. Allowances for doubtful accounts are established when the facts and circumstances indicate that a receivable may not be collectible. Potential credit risk exposure has been evaluated for the Company’s accounts receivable in accordance with ASC 326, Financial Instruments - Credit Losses. The Company assesses risk and determines a loss percentage by pooling account receivables based on similar risk characteristics. The loss percentage is calculated through the use of forecasts that are based on current and historical economic and financial information. Property, Plant and Equipment Property, plant and equipment are initially measured and recognized at acquisition cost, including any directly attributable cost of preparing the asset for its intended use or, in the case of assets acquired in a business combination, at fair value as at the date of the combination. After initial measurement, property, plant and equipment are carried at cost less accumulated depreciation and impairment. Repair and maintenance costs of property, plant and equipment are expensed as incurred. The depreciable value of property, plant and equipment, net of any residual value, is depreciated on a straight line basis over the useful life of the asset. The useful life of an asset is usually equivalent to its economic life. The useful lives of property, plant and equipment are as follows: • Machinery and Equipment: 5 years • Furniture, fixtures, and office equipment: 3 to 5 years • Computer equipment and software: 3 years • Building improvements and leasehold improvements: Shorter of the remaining life of the lease or 10 years The costs of assets retired or otherwise disposed of and the accumulated depreciation thereon are removed from the accounts, with any gain or loss realized upon sale or disposal credited or charged to operations. Revenue Recognition and Net Product Sales MACI, MACI Biopsy Kits, Epicel and NexoBrid The Company recognizes product revenue from sales to a customer (whether a distributor, or hospital ) following the five step model in ASC 606: (i) identify contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenues when (or as) the Company satisfies the performance obligation. Under this revenue standard, the Company recognizes revenue when its customer obtains control of the promised goods, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods. There are no contractual rights of returns, refunds or similar obligations related to MACI, kits, Epicel or NexoBrid as of December 31, 2020; however, in certain limited cases the Company will accept a product return if a surgery is canceled. Revenue is not recognized in certain canceled cases. For MACI, MACI kits and Epicel there are no variable pricing arrangements related to warranties or rebates offered to customers. The majority of orders are due within 60 to 90 days of delivery. Shipping and handling fees are included as a component of revenue. The Company recognizes any commission fees as an expense when incurred. These fees are included in selling, general, and administrative expenses. NexoBrid The U.S. Biomedical Advanced Research and Development Authority (BARDA) has committed to procure NexoBrid from MediWound, under which MediWound will manufacture and supply NexoBrid on a unit price basis, which may be increased pursuant to the terms of the agreement. The Company does not hold a direct contract or distribution agreement with BARDA, or take title to the product. The Company recognizes income from sales of NexoBrid to BARDA upon delivery, at which time BARDA is in control of the product. The Company does not control the specified goods or services before they are transferred to the customer. MediWound has promised to provide the goods to BARDA and has completed all significant compliance aspects of being a contractor for BARDA and continue to be responsible for all compliance. The Company records the NexoBrid revenue based on a specified percentage of the gross profit MediWound recognizes on the sale in accordance with the license agreement. Research and Development Expense Research and development activities represent a significant part of the Company’s business. These expenditures relate to the development of new products, improvement of existing products, technical support of products and compliance with governmental regulations for the protection of consumers and patients. Research and development expenses are expensed as incurred. Stock-Based Compensation The Company’s accounting for stock-based compensation requires it to determine the fair value of common stock issued in the form of stock option awards and restricted stock units. The Company uses the value of its common stock at the date of the grant in the calculation of the fair value of its share-based awards. The fair value of restricted stock units held by the employees is determined based on the fair value of the Company’s common stock on the date of the grant. The fair value of stock options held by the employees is determined using a Black-Scholes option valuation method, which is a valuation technique that is acceptable for share-based payment accounting. Key assumptions in determining fair value include volatility, risk-free interest rate, dividend yield and expected term. The assumptions used in calculating the fair value of stock options represent the Company’s best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the stock-based compensation expense could be materially different in the future. In addition, the Company estimates the expected forfeiture rate and only recognize expense for those stock options expected to vest over the service period. The estimated forfeiture rate considers the historical experience of the Company’s stock-based awards. If the actual forfeiture rate is different from the estimate, expense is adjusted accordingly. For certain non-employee consultants, stock option awards continue to vest post-termination. The Company also has an Employee Stock Purchase Plan (ESPP) which is a compensatory plan. Compensation expense is recorded based on the fair value of the purchase options at the grant date, which corresponds to the first day of each purchase period, and is amortized over the purchase period. Comprehensive Loss Comprehensive loss is the change in stockholders’ equity during a period arising from any gain or loss unrealized related to the Company’s investments. Income Taxes Deferred tax assets are recognized for deductible temporary differences and tax credit carryforwards and deferred tax liabilities are recognized for taxable temporary differences. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized based on the weight of available evidence, that a portion or all of the deferred tax assets will not be realized. When evaluating the realizability of the deferred tax assets, all evidence, both positive and negative, is considered. Items considered when evaluating the need for a valuation allowance include the ability to carry back losses, future reversals of existing temporary differences, tax planning strategies, and expectations of future earnings. The Company records uncertain tax positions in the consolidated financial statements only if it is more likely than not that the uncertain tax position will be sustained upon examination by the taxing authorities. The Company records interest and penalties related to uncertain tax positions in income tax expense. Net Income (Loss) Per Share Attributable to Common Shareholders Basic and diluted earnings (loss) per share is calculated using the two-class method. Basic earnings (loss) per share which is based on an earnings allocation formula that determines earnings (loss) per share for the holders of the Company’s common shares. There were no undeclared dividends for the year ended December 31, 2020 or 2019. Diluted earnings (loss) per share includes convertible securities or common equivalent share (stock options and warrants) in addition to the Company’s common shares. Common equivalent shares and treasury stock are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive. Financial Instruments The Company’s financial instruments include receivables for which the current carrying amounts approximate market value, based upon their short-term nature and marketable debt securities which are classified as available-for-sale and carried at fair value on a settlement date basis. Warrants Warrants that could be cash settled or have anti-dilution price protection provisions are recorded as liabilities at their estimated fair value at the date of issuance, with subsequent changes in estimated fair value recorded in other income (expense) in our statement of operations in each subsequent period. Warrants that meet the requirements for equity classification are recorded at fair value with no subsequent remeasurement. In general, warrants are measured using the Black-Scholes valuation model. The methodology is based, in part, upon inputs for which there is little or no observable market data, requiring the Company to develop its own assumptions. The assumptions used in calculating the estimated fair value of the warrants represent our best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the change in estimated fair value of the warrant liability for those warrants that could be cash settled or have anti-dilution price protection provisions, could be materially different. As of December 31, 2019 and 2020, there were no outstanding warrants.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Measuring Credit Losses on Financial Instruments The FASB issued updated guidance on measuring credit losses on financial instruments. The guidance removes the thresholds that companies apply to measure credit losses on financial instruments measured at amortized cost, such as loans, receivables, and held-to-maturity debt securities. Prior to the updated guidance, credit losses were recognized when it was probable that the loss had been incurred. The revised guidance removes all recognition thresholds and requires companies to recognize an allowance for credit losses for the difference between the amortized cost basis of a financial instrument and the amount of amortized cost that a company expected to collect over the instrument’s contractual life. The Accounting Standard Update (ASU) 2016-13 , Financial Instruments-Credit Losses (Topic 326) , became effective for the Company January 1, 2020. See note 4 and note 8 for further discussion. Fair Value Measurement Disclosure The FASB issued updated guidance through ASU 2018-13 , Fair Value Measurement (Topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. The revised guidance created a more consistent disclosure framework that increased clarity and removed, modified and added certain fair value disclosures to improve the effectiveness of the Company’s disclosures in the notes of the Consolidated Financial Statements. This guidance became effective for the Company January 1, 2020 and had no impact on its Consolidated Financial Statements. Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12 , Simplifying the Accounting for Income Taxes (ASC 740). The ASU enhances and simplifies various aspects of the income tax accounting guidance in ASC 740, including requirements related to hybrid tax regimes, the tax basis step-up in goodwill obtained in a transaction that is not a business combination, separate financial statements of entities not subject to tax, the intra-period tax allocation exception to the incremental approach, ownership changes in investments, changes from a subsidiary to an equity method investment, interim-period accounting for enacted changes in tax law, and the year-to-date loss limitation in interim-period tax accounting. This guidance is effective for the Company for annual and interim periods beginning after December 31, 2020; however, early adoption is permitted. The Company is currently in the process of evaluating the impact on its Consolidated Financial Statements.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Revenue	Revenue Revenue Recognition and Net Product Sales As disclosed in note 2, the Company recognizes product revenue from sales of MACI biopsy kits, MACI implants, Epicel grafts and other sources following the five-step model in Accounting Standards Codification 606, Revenue Recognition, (ASC 606). MACI Biopsy Kits MACI biopsy kits are sold directly to hospitals based on contracted rates in an approved contract or sales order. The Company recognizes MACI kit revenue upon delivery of the biopsy kit, at which time the customer (the facility) is in control of the kit. The kit is used by the doctor to provide a sample of cartilage tissue to the Company, which can later be used to manufacture a MACI implant. The ordering of the kit does not obligate the Company to manufacture an implant nor does the receipt of the cartilage tissue. The customer’s order of an implant is separate from the process of ordering the biopsy kit. Therefore, the sale of the biopsy kit and any subsequent sale of an implant are distinct contracts and are accounted for separately. MACI Implants The Company contracts with two specialty pharmacies, Orsini Pharmaceutical Services, Inc. (Orsini) and AllCare Plus Pharmacy, Inc. (AllCare) to distribute MACI in a manner in which the Company retains the credit and collection risk from the end customer. The Company pays both specialty pharmacies a fee for each patient to whom MACI is dispensed. Both Orsini and AllCare perform collection activities to collect payment from customers. The Company has engaged a third-party to provide services in connection with a patient support program to manage patient cases and to ensure complete and correct billing information is provided to the insurers and hospitals. In addition, the Company also sells MACI directly to DMS Pharmaceutical (DMS) for military patients. The sales directly to DMS are made at a contracted rate. Prior authorization and confirmation of coverage level by the patient’s private insurance plan, hospital or government payer is a prerequisite to the shipment of product to a patient. The Company recognizes product revenues from sales of all MACI implants upon delivery at which time the customer obtains control of the implant and the claim is billable. The total consideration which the Company expects to collect in exchange for MACI implants (the transaction price) may be fixed or variable. Direct sales to hospitals or distributors are recorded at a contracted price, and there are typically no forms of variable consideration. When the Company sells MACI the patient is responsible for payment; however, the Company is typically reimbursed by a third-party insurer or government payer, subject to a patient co-pay amount. Reimbursements from third-party insurers and government payers vary by patient and payer and are based on either contracted rates, publicly available rates, fee schedules or past payer precedents. Net product revenue is recognized net of estimated contractual allowances, which considers historical collection experience from both the payer and patient, denial rates and the terms of the Company’s contractual arrangements. The Company estimates expected collections for these transactions using the portfolio approach. The Company records a reduction to revenue at the time of sale for its estimate of the amount of consideration that will not be collected. In addition, potential credit risk exposure has been evaluated for the Company’s accounts receivable in accordance with ASC 326, Financial Instruments - Credit Losses. The Company assesses risk and determines a loss percentage by pooling account receivables based on similar risk characteristics. The loss percentage is calculated through the use of forecasts that are based on current and historical economic and financial information. This loss percentage was applied to the accounts receivables as of December 31, 2020. The total allowance for uncollectible consideration was $5.3 million and $3.9 million as of December 31, 2020, and 2019, respectively. Changes to the estimate of the amount of consideration that will not be collected could have a material impact to the revenue recognized. A 0.5% change to the estimated uncollectible percentage could result in approximately a $0.3 million decrease or increase in the revenue recognized for the year ended December 31, 2020. Changes in estimates of the transaction price are recorded through revenue in the period in which such change occurs. Changes in estimates related to prior period sales resulted in an increase to revenue of $0.7 million, increase of $0.7 million and decrease of $0.2 million for the years ended December 31, 2020, 2019, and 2018, respectively. Epicel The Company sells Epicel directly to hospitals based on contracted rates stated in an approved contract or purchase order. Similar to MACI, there is no obligation to manufacture Epicel grafts upon receipt of a skin biopsy, and Vericel has no contractual right to receive payment until the product is delivered to the hospital. The Company recognizes product revenues from sales of Epicel upon delivery to the hospital, at which time the customer is in control of the Epicel grafts and the claim is billable to the hospital. NexoBrid The Company entered into exclusive license and supply agreements with MediWound, under which MediWound will manufacture and supply NexoBrid on a unit price basis, which may be increased pursuant to the terms of the agreement. BARDA has committed to procure NexoBrid from MediWound and, as of December 31, 2020, the Company did not hold a direct contract or distribution agreement with BARDA, or take title to the product. The Company recognizes revenue based on a percentage of gross profits for sales of NexoBrid to BARDA upon delivery, at which time BARDA is in control of the product. For the year ended December 31, 2020, the first orders of NexoBrid were delivered and the Company recognized $2.2 million of revenue. See note 16 for further discussion of the NexoBrid license and supply agreements. Revenue by Product and Customer The following table and description below shows the products from which the Company generated its revenue: Year Ended December 31, Revenue by product (in thousands) 2020 2019 2018 MACI and Carticel implants and kits Implants based on contracted rate sold through a specialty pharmacy (a) $ 57,593 $ 56,185 $ 42,926 Implants subject to third-party reimbursement sold through a specialty pharmacy (b) 16,320 17,076 8,621 Implants sold direct based on contracted rates (c) 15,144 13,933 12,122 Implants sold direct subject to third-party reimbursement (d) 2,754 1,529 2,257 Biopsy kits - direct bill 1,908 2,243 1,997 Change in estimates related to prior periods (e) 713 654 (182) Epicel Direct bill (hospital) 27,536 26,230 23,116 NexoBrid (f) 2,211 — — Total revenue $ 124,179 $ 117,850 $ 90,857 (a) Represents implants sold through Orsini and AllCare whereby such specialty pharmacies have a direct contract with the underlying insurance provider. The amount of reimbursement is based on contracted rates at the time of sale supported by the pharmacy's direct contracts. (b) Represents implants sold through Orsini or AllCare whereby such specialty pharmacy does not have a direct contract with the underlying payer. The amount of reimbursement is established based on a payer or state fee schedule and/or payer history. (c) Represents implants sold directly from the Company to the facility based on a contract and known price agreed upon prior to the surgery date. Also represents direct sales under a contract to specialty distributor DMS. (d) Represents implants sold directly from the Company to the facility based on a contract and known price agreed upon prior to the surgery date. The payment terms are subject to third-party reimbursement from an underlying insurance provider. (e) Primarily represents changes in estimates related to implants sold through Orsini or AllCare in which such specialty pharmacy does not have a direct contract with the underlying payer. The initial estimate of the amount of reimbursement is established based on a payer or state fee schedule and/or payer history. The change in estimates is a result of additional information, changes in collection expectations or actual cash collections received in the current period. (f) Represents revenue based on a percentage of gross profits for sales of NexoBrid to BARDA, pursuant to the license agreement between the Company and MediWound. Concentration of Credit Risk For the year ended December 31, 2018, MACI revenue concentration from its largest customer was 16%. The Company’s total revenue and accounts receivable balances for the years ended December 31, 2020 and 2019 from its largest customer of MACI and Epicel did not exceed 10%.

Selected Balance Sheet Componen

Selected Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Selected Balance Sheet Components	Selected Balance Sheet Components Inventory Inventory as of December 31, 2020 and 2019: (In thousands) 2020 2019 Raw materials $ 8,775 $ 6,085 Work-in-process 537 541 Finished goods 44 190 Inventory $ 9,356 $ 6,816 Property and Equipment Property and Equipment, net as of December 31, 2020 and 2019: (In thousands) 2020 2019 Machinery and equipment $ 3,672 $ 3,152 Furniture, fixtures and office equipment 809 775 Computer equipment and software 6,846 6,174 Leasehold improvements 5,560 5,256 Construction in process 2,021 859 Financing right-of-use lease 111 148 Total property and equipment, gross 19,019 16,364 Less accumulated depreciation (11,386) (9,220) $ 7,633 $ 7,144 Depreciation expense for the years ended December 31, 2020, 2019 and 2018 was $2.4 million, $1.7 million and $1.4 million, respectively. Accrued Expenses Accrued Expenses as of December 31, 2020 and 2019: (In thousands) 2020 2019 Bonus related compensation $ 5,721 $ 5,116 Employee related accruals 3,482 1,785 Other accrued expenses 2,090 1,047 Accrued expenses $ 11,293 $ 7,948

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt On December 19, 2018, the Company prepaid in full all outstanding indebtedness under, and terminated, the Loan and Security Agreement dated as of September 9, 2016, by and between the Company, Silicon Valley Bank as Agent and Silicon Valley Bank, MidCap Financial Trust, MidCap Funding III Trust and other lenders listed therein as lenders (SVB Loan Agreement), as amended December 30, 2016, May 9, 2017 and December 6, 2017, which termination was effective December 19, 2018. Warrants were issued to SVB and MidCap in conjunction with the modified debt agreement. On the date of termination, the Company paid in full $17.1 million in outstanding borrowings at the time of termination. In connection with the termination of the SVB Loan Agreement, the Company paid an additional prepayment premium of 1.5% in the amount of $0.2 million and a final payment of 3.6% in the amount of $0.5 million.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases The Company leases facilities in Ann Arbor, Michigan and Cambridge, Massachusetts. The Ann Arbor facility includes office space, and the Cambridge facility includes clean rooms, laboratories for MACI and Epicel manufacturing and office space. The Company also leases offsite warehouse space, vehicles and computer equipment. Certain of the Company’s lease agreements include lease payments that are adjusted periodically for an index or rate. The leases are initially measured using the present value of the projected payments adjusted for the index or rate in effect at the commencement date. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. All operating lease commitments with a lease term greater than 12 months are recognized as right-of-use assets and liabilities, on a discounted basis on the balance sheet. Effective October 21, 2020 the Company entered into an agreement with one of its Cambridge, Massachusetts facility leases. The agreement extended the terms of the lease to expire on February 29, 2032, with monthly contractual lease payments ranging from $0.4 million to $0.6 million. The agreement also provides a tenant improvement allowance of approximately $4.3 million, available through December 31, 2023. Leases with an initial term of 12 months or less are not recorded on the balance sheet and for the year ended December 31, 2020 and 2019, lease expense of less than $0.1 million was recorded related to short-term leases. The contribution toward the cost of tenant improvements is recorded as a reduction of the operating lease assets. For the years ended December 31, 2020, 2019, the Company recognized $6.3 million and $5.4 million, respectively, and in 2018 (under the prior leasing guidance) the Company recognized $5.2 million of operating lease expense. For the years ended December 31, 2020, 2019 and 2018, the Company recognized less than $0.1 million of financing lease expense. The Company’s leases contain non-lease components and activities that do not transfer a good or service to the Company. The Company elected not to combine lease and non-lease components and therefore non-lease costs were not included in the net lease assets or lease liabilities. Total leased assets and liabilities classified on the balance sheet as of December 31, 2020 and 2019 are as follows: December 31, (In thousands) Classification 2020 2019 Assets Operating Right-of-use assets $ 50,105 $ 25,103 Finance Property and equipment, net 111 148 $ 50,216 $ 25,251 Liabilities Current Operating Current portion of operating lease liabilities $ 4,394 $ 5,461 Finance Other liabilities 41 41 $ 4,435 $ 5,502 Non-current Operating Operating lease liabilities $ 48,789 $ 22,242 Finance Other long-term liabilities 76 110 $ 48,865 $ 22,352 Cash paid for amounts included in the measurement of the Company’s operating lease liabilities was $5.8 million and $5.0 million for the year ended December 31, 2020 and 2019, respectively. Maturity of lease liabilities as of December 31, 2020 are as follows: (In thousands) Operating Leases Finance Leases Total 2021 $ 4,394 $ 41 $ 4,435 2022 4,177 41 4,218 2023 6,973 41 7,014 2024 6,934 — 6,934 2025 6,340 — 6,340 more than 5 years 43,507 — 43,507 Total lease payments $ 72,325 $ 123 $ 72,448 Less: interest (19,142) (7) (19,149) Present value of lease liabilities $ 53,183 $ 116 $ 53,299 An explicit rate is not provided in some of the Company’s leases, therefore the Company uses a mix of incremental borrowing rate based on the information available at commencement date through market sources including relevant peer borrowing rates, as well as implicit and explicit rates in determining the present value of lease payments. The Company has options to renew lease terms for facilities and other assets. The exercise of lease renewal options is generally at the Company’s sole discretion. The Company evaluates renewal and termination options at the lease commencement date to determine if it is reasonably certain to exercise the option on the basis of economic factors. For certain leases, the Company’s exercise of the renewal option was determined to be probable and the renewal period was accordingly included in the lease term and related calculations. Lease terms and discount rates as of December 31, 2020 are as follows: December 31, 2020 2019 Weighted-average remaining lease term (years) Operating leases 10.6 6.8 Finance leases 2.5 3.5 Weighted-average discount rate Operating leases 5.42% 9.44% Finance leases 5.00% 5.00%
Leases	Leases The Company leases facilities in Ann Arbor, Michigan and Cambridge, Massachusetts. The Ann Arbor facility includes office space, and the Cambridge facility includes clean rooms, laboratories for MACI and Epicel manufacturing and office space. The Company also leases offsite warehouse space, vehicles and computer equipment. Certain of the Company’s lease agreements include lease payments that are adjusted periodically for an index or rate. The leases are initially measured using the present value of the projected payments adjusted for the index or rate in effect at the commencement date. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. All operating lease commitments with a lease term greater than 12 months are recognized as right-of-use assets and liabilities, on a discounted basis on the balance sheet. Effective October 21, 2020 the Company entered into an agreement with one of its Cambridge, Massachusetts facility leases. The agreement extended the terms of the lease to expire on February 29, 2032, with monthly contractual lease payments ranging from $0.4 million to $0.6 million. The agreement also provides a tenant improvement allowance of approximately $4.3 million, available through December 31, 2023. Leases with an initial term of 12 months or less are not recorded on the balance sheet and for the year ended December 31, 2020 and 2019, lease expense of less than $0.1 million was recorded related to short-term leases. The contribution toward the cost of tenant improvements is recorded as a reduction of the operating lease assets. For the years ended December 31, 2020, 2019, the Company recognized $6.3 million and $5.4 million, respectively, and in 2018 (under the prior leasing guidance) the Company recognized $5.2 million of operating lease expense. For the years ended December 31, 2020, 2019 and 2018, the Company recognized less than $0.1 million of financing lease expense. The Company’s leases contain non-lease components and activities that do not transfer a good or service to the Company. The Company elected not to combine lease and non-lease components and therefore non-lease costs were not included in the net lease assets or lease liabilities. Total leased assets and liabilities classified on the balance sheet as of December 31, 2020 and 2019 are as follows: December 31, (In thousands) Classification 2020 2019 Assets Operating Right-of-use assets $ 50,105 $ 25,103 Finance Property and equipment, net 111 148 $ 50,216 $ 25,251 Liabilities Current Operating Current portion of operating lease liabilities $ 4,394 $ 5,461 Finance Other liabilities 41 41 $ 4,435 $ 5,502 Non-current Operating Operating lease liabilities $ 48,789 $ 22,242 Finance Other long-term liabilities 76 110 $ 48,865 $ 22,352 Cash paid for amounts included in the measurement of the Company’s operating lease liabilities was $5.8 million and $5.0 million for the year ended December 31, 2020 and 2019, respectively. Maturity of lease liabilities as of December 31, 2020 are as follows: (In thousands) Operating Leases Finance Leases Total 2021 $ 4,394 $ 41 $ 4,435 2022 4,177 41 4,218 2023 6,973 41 7,014 2024 6,934 — 6,934 2025 6,340 — 6,340 more than 5 years 43,507 — 43,507 Total lease payments $ 72,325 $ 123 $ 72,448 Less: interest (19,142) (7) (19,149) Present value of lease liabilities $ 53,183 $ 116 $ 53,299 An explicit rate is not provided in some of the Company’s leases, therefore the Company uses a mix of incremental borrowing rate based on the information available at commencement date through market sources including relevant peer borrowing rates, as well as implicit and explicit rates in determining the present value of lease payments. The Company has options to renew lease terms for facilities and other assets. The exercise of lease renewal options is generally at the Company’s sole discretion. The Company evaluates renewal and termination options at the lease commencement date to determine if it is reasonably certain to exercise the option on the basis of economic factors. For certain leases, the Company’s exercise of the renewal option was determined to be probable and the renewal period was accordingly included in the lease term and related calculations. Lease terms and discount rates as of December 31, 2020 are as follows: December 31, 2020 2019 Weighted-average remaining lease term (years) Operating leases 10.6 6.8 Finance leases 2.5 3.5 Weighted-average discount rate Operating leases 5.42% 9.44% Finance leases 5.00% 5.00%

Cash Equivalents and Investment

Cash Equivalents and Investments	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Cash Equivalents and Investments	Cash Equivalents and Investments Marketable debt securities held by the Company are classified as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities , and carried at fair value in the balance sheets on a settlement date basis. The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2020 and December 31, 2019: December 31, 2020 Gross Unrealized Amortized Cost Gains Losses Credit Losses Estimated Fair Value Money market funds $ 3,698 $ — $ — $ — $ 3,698 Commercial paper 8,993 1 — — 8,994 Corporate notes 35,917 — — (6) 35,911 U.S. government securities 12,828 14 — — 12,842 U.S. government agency bonds 5,000 1 — — 5,001 U.S. asset-backed securities 3,534 4 — — 3,538 $ 69,970 $ 20 $ — $ (6) $ 69,984 Classified as: Cash equivalents $ 3,698 Short-term investments 42,187 Long-term investments 24,099 $ 69,984 December 31, 2019 Gross Unrealized (In thousands) Amortized Cost Gains Losses Estimated Fair Value Money market funds $ 5,381 $ — $ — $ 5,381 Commercial paper 11,892 — — 11,892 Corporate notes 18,369 11 — 18,380 U.S. government securities 11,291 4 — 11,295 U.S. asset-backed securities 10,503 6 — 10,509 $ 57,436 $ 21 $ — $ 57,457 Classified as: Cash equivalents $ 5,381 Short-term investments 42,829 Long-term investments 9,247 $ 57,457

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Option, Restricted Stock Units and Equity Incentive Plans The Company has historically had various stock incentive plans and agreements that provide for the issuance of nonqualified and incentive stock options and restricted stock units as well as other equity awards. Such awards may be granted by the Company’s Board of Directors to certain of the Company’s employees, directors and consultants. Options and restricted stock units granted to employees and non-employees under these plans expire no later than ten years from the date of grant. Options and restricted stock units generally become exercisable or vest over a four year period, under a graded-vesting methodology for stock options and annually on the anniversary grant date for restricted stock units, following the date of grant. The Company generally issues new shares upon the exercise of stock options or vesting of restricted stock units. The Amended and Restated 2019 Omnibus Incentive Plan (2019 Plan) was approved on April 29, 2020 and provides incentives through the grant of stock options, stock appreciation rights, restricted stock awards and restricted stock units. The exercise price of stock options granted under the 2019 Plan shall not be less than the fair market value of the Company’s common stock on the date of grant. The 2019 Plan replaced the 1992 Stock Option Plan, the 2001 Stock Option Plan, the Amended and Restated 2004 Equity Incentive Plan, the 2009 Second Amended and Restated Omnibus Incentive Plan and the 2017 Omnibus Incentive Plan (Prior Plans), and no new grants have been granted under the Prior Plans after approval. However, the expiration or forfeiture of options previously granted under the Prior Plans will increase the number of shares available for issuance under the 2019 Plan. As of December 31, 2020, there were 4,544,084 shares available for future grant under the 2019 Plan. Employee Stock Purchase Plan Employees are able to purchase stock under the ESPP. The ESPP allows for the issuance of an aggregate of 1,000,000 shares of common stock of which 708,452 have been issued since the inception of the benefit in 2015. Participation in this plan is available to substantially all employees. The ESPP is a compensatory plan accounted for under the expense recognition provisions of the share-based payment accounting standards. Compensation expense is recorded based on the fair market value of the purchase options at the grant date, which corresponds to the first day of each purchase period and is amortized over the purchase period. In January 2021, employees purchased 14,954 shares resulting in proceeds from the sale of common stock of $0.2 million under the ESPP for the fourth quarter of 2020. The total share-based compensation expense for the ESPP for the years ended December 31, 2020, 2019, and 2018 was approximately $0.4 million, $0.3 million, and $0.3 million, respectively. Service-Based Stock Options During the year ended December 31, 2020, the Company granted 1,356,540 service-based options to purchase common stock. The exercise price of the options is the fair market value per share of common stock on the grant date, generally vest over four years (other than 78,750 non-employee director options which vest over one year) and have a term of ten years. The weighted-average grant-date fair value of service-based options granted during the years ended December 31, 2020, 2019, and 2018 was $8.86, $12.62 and $6.96, respectively. The net compensation costs recorded for the service-based stock options related to employees and directors (including the impact of forfeitures) for the years ended December 31, 2020, 2019, and 2018 were $12.1 million, $11.8 million and $6.9 million, respectively. The fair value of each service-based stock option grant for the reported periods is estimated on the date of the grant using the Black-Scholes option-pricing model using the weighted-average assumptions noted in the following table: Year Ended December 31, Service-Based Stock Options 2020 2019 2018 Expected dividend rate —% —% —% Expected stock price volatility 71.1 - 78.7% 77.9 - 85.5% 82.3 – 88.3% Risk-free interest rate 0.33 - 1.7% 1.4 - 2.7% 2.4 – 3.1% Expected life (years) 5.3 - 6.3 5.3 - 6.3 5.3 - 6.3 The following table summarizes the activity for service-based stock options for the indicated periods: Service-Based Stock Options Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (Thousands) Outstanding at December 31, 2019 5,052,950 $ 10.35 7.7 $ 37,974 Granted 1,356,540 13.42 Exercised (790,532) 7.06 Expired (29,115) 21.38 Forfeited (353,799) 13.82 Outstanding at December 31, 2020 5,236,044 $ 11.34 7.3 $ 102,654 Exercisable at December 31, 2020 2,885,729 $ 9.16 6.4 $ 63,037 As of December 31, 2020, 4,949,912 shares are vested and expected to vest. As of December 31, 2020, there was approximately $13.1 million, of total unrecognized compensation cost related to non-vested service-based stock options granted under the 2019 Plan and the Prior Plans. That cost is expected to be recognized over a weighted-average period o f 2.7 y ears. The total intrinsic value of stock options exercised for the years ended December 31, 2020, 2019, and 2018 was $10.5 million, $16.1 million and $11.4 million, respectively. Restricted Stock Units The restricted stock units vest annually over four years in equal installments commencing on the first anniversary of the grant date (other than non-employee director options which vest over one year from the grant date). The Company issues new shares upon the vesting of restricted stock units. Restricted stock awards are recorded at fair value at the date of grant, which is based on the closing share price on the grant date. Compensation expense is recorded for restricted stock units that are expected to vest based on their fair value at the grant date and is amortized over the expected vesting period. As restricted stock units vest, a portion of the shares awarded are withheld and net settled by the Company to cover employee tax obligations. As a result of 46,712 units vesting during the year ended December 31, 2020, 13,872 shares were withheld for payment of taxes on the employees’ behalf and retired from the 2019 Plan. No shares were withheld for payment of taxes on 10,500 of the vested units, as no shares are withheld at vesting for shares awarded to the Company’s Board of Directors. The following table summarizes the activity for restricted stock awards for the indicated periods: Restricted Stock Units Number of Restricted Stock Awards Weighted-Average Grant Date Fair Value Weighted-Average Term Aggregate Intrinsic Value Outstanding at December 31, 2019 157,030 $ 17.80 1.6 $ 2,732 Granted 196,836 11.41 2,246 Vested (46,712) 17.59 Forfeited (36,515) 15.00 Unvested at December 31, 2020 270,639 $ 13.57 1.4 $ 8,357 The total grant-date fair value of restricted stock units granted in the year ended December 31, 2020 and 2019 was $2.2 million and $3.3 million, respectively. The net compensation costs recorded for the service-based restricted stock units related to employees and directors (including the impact of forfeitures) for the year ended December 31, 2020, and 2019 was $1.4 million and $1.0 million, respectively. At December 31, 2020 and 2019, the total unrecognized compensation cost related to the restricted stock awards was $2.1 million and $1.8 million, respectively, and the weighted-average period over which that cost is expected to be recognized was 2.7 and 3.1 years for the same periods, respectively. The total fair value of restricted stock awards vested in the year ended December 31, 2020 was $0.6 million and no awards were vested in the year ended December 31, 2019. Stock Compensation Expense Non-cash stock-based compensation expense (employee stock purchase plan, service-based stock options and restricted stock units) included in cost of goods sold, research and development expenses and selling, general and administrative expenses is summarized in the following table: Years Ended December 31, (in thousands) 2020 2019 2018 Cost of goods sold $ 1,949 $ 2,029 $ 1,015 Research and development 1,884 2,428 1,672 Selling, general and administrative 10,010 8,722 4,536 Total non-cash stock-based compensation expense $ 13,843 $ 13,179 $ 7,223

Net Income (Loss) Per Common Sh

Net Income (Loss) Per Common Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Income (Loss) Per Common Share	Net Income (Loss) Per Common Share The following reflects the net income (loss) attributable to common shareholders and share data used in the basic and diluted earnings per share computations using the two class method: Year Ended December 31, (Amounts in thousands, except per share amounts) 2020 2019 2018 Numerator: Net income (loss) $ 2,864 $ (9,665) $ (8,137) Denominator: Weighted-average common shares outstanding (basic) 45,221 44,180 40,242 Net income (loss) per share attributable to common shareholders (basic) $ 0.06 $ (0.22) $ (0.20) Weighted-average common shares outstanding (diluted) 47,282 44,180 40,242 Net income (loss) per share attributable to common shareholders (diluted) $ 0.06 $ (0.22) $ (0.20) Anti-dilutive shares excluded from the calculation of diluted earnings per share (a) (amounts in millions): Stock options 2.2 5.1 4.8 Restricted stock unit awards — 0.2 — (a) Common equivalent shares are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholder's Equity Public Equity Offering In June 2018, the Company sold 5,750,000 shares of its common stock in an underwritten public offering at a price of $13.00 per share. The Company received proceeds of $70.1 million, net of $4.7 million of underwriters’ discount and issuance costs consisting primarily of legal and accounting fees. The Company recorded these proceeds as a common stock issuance.

Stock Purchase Warrants

Stock Purchase Warrants	12 Months Ended
	Dec. 31, 2020
Warrants and Rights Note Disclosure [Abstract]
Stock Purchase Warrants	Stock Purchase Warrants The Company has historically issued warrants to purchase shares of the Company’s common stock in connection with certain of its common stock offerings. The fair value of warrants previously issued were measured using the Black-Scholes valuation model. Inherent in the Black-Scholes valuation model are assumptions related to expected stock-price volatility, expected life, risk-free interest rate and dividend yield. The Company estimates the volatility of its common stock-based on historical volatility that matches the expected remaining life of the warrants. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield curve on the grant date for a maturity similar to the expected remaining life of the warrants. The expected life of the warrants is assumed to be equivalent to their remaining contractual term. The dividend rate is based on the historical rate, which the Company anticipates will remain at zero.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company’s fair value measurements are classified and disclosed in one of the following three categories: • Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; • Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). There was no movement between Level 1 and Level 2 or between Level 2 and Level 3 from December 31, 2019 to December 31, 2020. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The commercial paper, corporate notes, U.S. government securities, U.S. government agency bonds and U.S. asset-backed securities are classified as Level 2 as they were valued based upon quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. The following table summarizes the valuation of the Company’s financial instruments that are measured at fair value on a recurring basis: December 31, 2020 December 31, 2019 Fair value measurement category Fair value measurement category (In thousands) Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Assets: Money market funds $ 3,698 $ 3,698 $ — $ — $ 5,381 $ 5,381 $ — $ — Commercial paper 8,994 — 8,994 — 11,892 — 11,892 — Corporate notes 35,911 — 35,911 — 18,380 — 18,380 — U.S. government securities 12,842 — 12,842 — 11,295 — 11,295 — U.S. government agency bonds 5,001 — 5,001 — — — — — U.S. asset-backed securities 3,538 — 3,538 — 10,509 — 10,509 — $ 69,984 $ 3,698 $ 66,286 $ — $ 57,457 $ 5,381 $ 52,076 $ — The fair values of the cash equivalents and marketable securities are based on observable market prices. The Company’s accounts receivables, accounts payable and accrued expenses are valued at cost which approximates fair value.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Loss before income taxes for U.S and non-U.S operations was as follows: Year Ended December 31, 2020 2019 2018 U.S. income (loss) $ 2,767 $ (9,632) $ (8,056) Non U.S. income (loss) 97 (33) (81) $ 2,864 $ (9,665) $ (8,137) A reconciliation of income taxes computed using the federal statutory rate to the taxes reported in the consolidated statements of operations is as follows: Year Ended December 31, (In thousands) 2020 2019 2018 Income (loss) before income taxes $ 2,864 $ (9,665) $ (8,137) Federal statutory rate 21 % 21 % 21 % Taxes computed at federal statutory rate 601 (2,030) (1,709) State and local income taxes 200 (484) (385) Nondeductible share-based compensation 437 (1,329) (605) Federal and state rate change 249 (164) 839 Research and orphan drug credits (8,827) — — Other 132 (49) 172 Change in valuation allowance 7,388 4,056 1,688 Reported income taxes $ 180 $ — $ — Deferred tax assets (liabilities) consist of the following: Year Ended December 31, (In thousands) 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 8,411 $ 10,542 Employee benefits and stock compensation 5,692 4,329 Research and development costs 6,411 7,851 Intangible assets 3,279 4,350 Operating lease liability 13,687 7,245 Inventory reserve 3,813 3,303 Tax credit carryforward 10,085 — Other, net 38 119 Total deferred tax assets 51,416 37,739 Less: valuation allowance (37,379) (29,991) Total net deferred tax assets 14,037 7,748 Deferred tax liabilities: Right of use asset (13,463) (7,143) Fixed assets (574) (605) Total net deferred tax liabilities (14,037) (7,748) Net deferred tax assets and liabilities $ — $ — For the year-ended December 31, 2020, we recorded income tax expense as a result of taxable income in certain states where the net operating loss carryforwards and related deferred tax assets have been fully utilized. As of December 31, 2020, the Company’s U.S. federal and state tax net operating loss carryforwards available to offset future profits, after considering the annual Section 382 limit described below, are $32.3 million and $21.3 million, respectively. These net operating loss carryforwards will expire between 2021 and 2039 with the exception of the federal net operating loss generated in 2018. The federal net operating loss of $1.5 million generated in 2018 can be carried forward indefinitely. The projected annual limitation on the use of the net operating losses that existed prior to September 17, 2014 as a result of our change in control in 2014 per Section 382 of the Internal Revenue Code is $0.8 million. As a result, a significant portion of the net operating losses and tax credit carryforwards will expire prior to their utilization, regardless of the level of future profitability. As of December 31, 2020, the Company’s U.S. federal tax credit carryforwards available to offset future profits are $10.1 million. During 2020, the Company determined to pursue certain available tax credits and performed a research and development and orphan drug credit tax studies. As a result of completion of these studies it was determined that the Company now has a sufficient basis to claim the credits and has recognized a tax credit carryforward in the current period. These credit carryforwards will expire between 2034 and 2040. In accordance with the accounting guidance for income taxes, the Company estimated whether recoverability of its deferred tax assets is “more likely than not,” based on forecasts of taxable income in the related tax jurisdictions. In this estimate, the Company uses historical results, projected future operating results based upon approved business plans, eligible carry forward periods, tax planning opportunities and other relevant considerations. Based on these factors, including historical losses incurred by the Company, a full valuation allowance for the deferred tax assets, including the deferred tax assets for the aforementioned net operating losses and credits, has been provided since they are not more likely than not to be realized. If the Company continues to achieve profitability, these deferred tax assets may be available to offset future income taxes and the valuation could be released. The change in the valuation allowance was an increase of $7.4 million and $4.1 million for the years ended December 31, 2020 and 2019, respectively. The Company assesses uncertain tax positions in accordance with the guidance for accounting for uncertain tax positions. This pronouncement prescribes a recognition threshold and measurement methodology for recording within the financial statements uncertain tax positions taken, or expected to be taken, in the Company’s income tax returns. To the extent the uncertain tax positions do not meet the “more likely than not” threshold, the Company has derecognized such positions. To the extent the uncertain tax positions meet the “more likely than not” threshold, the Company has measured and recorded the highest probable benefit, and have established appropriate reserves for benefits that exceed the amount likely to be sustained upon examination. The Company currently has not recorded any uncertain tax positions and does not anticipate that the unrecognized tax benefits will significantly increase or decrease within the next twelve months. The Company files U.S. federal and state income tax returns with varying statute of limitations. During the year-ended December 31, 2020 examinations by U.S. tax authorities have been completed for 2017 and 2018. Due to the Company’s net operating loss carryforwards, federal income tax returns from incorporation are still subject to examination. The Company files in several state tax jurisdictions and are subject to examination in years ranging from incorporation to 2020.

Employee Savings Plan

Employee Savings Plan	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Savings Plan	Employee Savings Plan The Company has a 401(k) savings plan that allows participating employees to contribute a portion of their salary, subject to annual limits and minimum qualifications. The Board may, at its sole discretion, approve Company matching contributions to the plan. The Company made contributions of $0.8 million, $0.7 million and $0.6 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Nexobrid License and Supply Agr

Nexobrid License and Supply Agreements	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
NexoBrid License and Supply Agreements	NexoBrid License and Supply Agreements On May 6, 2019, the Company entered into exclusive license and supply agreements with MediWound to commercialize NexoBrid and any improvements to NexoBrid in North America. NexoBrid is a topically-administered biological product that enzymatically removes nonviable burn tissue, or eschar. On June 30, 2020, the Company announced the submission of a BLA to the FDA seeking the approval of NexoBrid for eschar removal (debridement) in adults with deep partial-thickness and/or full-thickness thermal burns. Subsequently, on September 16, 2020, the Company announced that the FDA accepted the BLA for review and has assigned a Prescription Drug User Fee Act (PDUFA) target date of June 29, 2021. Pursuant to the terms of the license agreement, if the BLA is approved, MediWound will transfer the BLA to Vericel and Vericel will market NexoBrid in the U.S. Both MediWound and Vericel, under the supervision of a Central Steering Committee comprised of members of both companies will continue to guide the development of NexoBrid in North America. NexoBrid is approved in the European Union and other international markets and has been designated as an orphan biologic in the United States, European Union and other international markets. In May 2019, the Company paid MediWound $17.5 million in consideration for the license. The $17.5 million upfront payment was recorded to research and development expense during 2019, as the license was considered in process research and development. The Company is also obligated to pay MediWound $7.5 million, which is contingent upon U.S. regulatory approval of the BLA for NexoBrid and up to $125 million contingent upon meeting certain sales milestones. The first sales milestone of $7.5 million would be triggered when annual net sales of NexoBrid or improvements to it in North America exceed $75 million. As of December 31, 2020, the milestone payments are not yet probable and therefore, not considered a liability. The Company also will pay MediWound tiered royalties on net sales ranging from mid-high single-digit to mid-teen percentages, subject to customary reductions. The Company also entered into a supply agreement with MediWound under which MediWound will manufacture NexoBrid for the Company on a unit price basis which may be increased based on a published index. MediWound is obligated to supply the Company with NexoBrid for sale in North America on an exclusive basis for the first five years of the term of the supply agreement. After the exclusivity period or upon supply failure, the Company will be permitted to establish an alternate source of supply.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Manufacturing and Supply Agreements Matricel — In October 2015, the Company signed a long-term supply agreement with Matricel GmbH for the ACI-Maix collagen membrane used in the manufacture of MACI. The Company and Matricel amended the agreement on March 17, 2018. Under the agreement, the Company has committed to purchase annually approximately $0.6 million per year, the Company has fulfilled this commitment for the years ended December 31, 2020, 2019 and 2018, respectively. The agreement is effective until December 31, 2022 and contains a 5-year renewal option by the Company and an additional 5-year automatic renewal, unless otherwise terminated. Manufacture, Supply and Other Agreements — The Company has entered into various agreements relating to the manufacture of its products and the supply of certain components. If the manufacturing or supply agreements expire or are otherwise terminated, the Company may not be able to identify and obtain ancillary materials that are necessary to develop its products and such expiration and termination could have a material effect on the Company’s business. The Company’s purchase commitments consist of minimum purchase amounts of materials used in the Company's cell manufacturing process to manufacture its marketed cell therapy products. Future minimum purchase commitments related to our contractual obligations are as follows: Payments Due by Period Contractual Obligations (in thousands) Total 2021 2022 2023 2024 2025 More than 5 Years Purchase commitments $ 7,864 $ 7,182 $ 682 $ — $ — $ — $ —

Supplementary Quarterly Financi

Supplementary Quarterly Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Supplementary Quarterly Financial Information (unaudited)	Supplementary Quarterly Financial Information (unaudited) Quarterly earnings per share amounts may not sum to the totals for each of the years, since quarterly computations are based on weighted-average common shares outstanding during each quarter. In thousands, except per share data First Quarter Second Quarter Third Quarter Fourth Quarter Year 2020 Revenues $ 26,678 $ 20,014 $ 32,258 $ 45,229 $ 124,179 Gross profit 16,756 11,354 22,471 33,647 84,228 Income (Loss) from operations (5,076) (8,358) 3,517 12,289 2,372 Net Income (loss) (4,705) (8,269) 3,618 12,220 2,864 Net Income (loss) per share (Basic) (0.10) (0.18) 0.08 0.27 0.06 Net Income (loss) per share (Diluted) (0.10) (0.18) 0.08 0.25 0.06 2019 Revenues $ 21,810 $ 26,151 $ 30,499 $ 39,390 $ 117,850 Gross profit 13,170 17,129 21,175 28,805 80,279 Income (Loss) from operations (3,358) (20,200) 3,097 9,210 (11,251) Net Income (loss) (2,844) (19,792) 3,470 9,501 (9,665) Net Income (loss) per share (Basic) (0.07) (0.45) 0.08 0.21 (0.22) Net Income (loss) per share (Diluted) (0.07) (0.45) 0.07 0.20 (0.22)

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of Vericel and its wholly-owned subsidiaries, Vericel Denmark ApS, in Kastrup, Demark and Vericel Security Corporation (collectively, the Company). All inter-company transactions and accounts have been eliminated in consolidation. Vericel Denmark ApS ceased operations in 2015.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of expenses during the reported period. The Company is monitoring the potential impact of the COVID-19 pandemic on its business and financial statements. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments reflected in these financial statements or a revision of the carrying value of its assets or liabilities as of the issuance of these financial statements. These estimates may change as new events occur and additional information is obtained. Actual results could differ from those estimates.
Cash Equivalents	Cash Equivalents Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less from the date of purchase and consist primarily of demand deposits, money market funds, overnight repurchase agreements and short duration agency bonds and commercial paper.
Restricted cash	Restricted cash Amounts included in restricted cash represent those required to be set aside to meet contractual terms of a lease agreement held by the Company.
Investments	Investments Investments classified as short-term have maturities of less than one year. Investments classified as long-term are those that: (i) have a maturity of greater than one year, and (ii) we do not intend to liquidate within the next twelve months, although these funds are available for use and, therefore, are classified as available-for-sale. The Company’s investment strategy is to buy short-duration marketable securities with a high credit rating. As of December 31, 2020 and 2019, all marketable securities held by the Company had remaining contractual maturities of three years or less. Unrealized gains are included as a component of accumulated other comprehensive income in the consolidated balance sheets and statements of stockholders’ equity and a component of total comprehensive income (loss) in the consolidated statements of comprehensive income (loss), until realized. Unrealized losses are evaluated for impairment under ASC 326, Financial Instruments - Credit Losses
Inventory	Inventory Inventories are measured at the lower of cost or net realizable value. Cost is calculated based upon standard-cost which approximates costs determined on the first-in, first-out method. The Company periodically reviews its inventories for excess or obsolescence and writes down obsolete or other unmarketable inventory to its estimated net realizable value. If the actual net realizable value is less than that estimated by the Company, or if it is determined that inventory utilization will further diminish based on estimates of demand, additional inventory write-downs may be required. In all cases, product inventory is carried at the lower of cost or its estimated net realizable value. Amounts written down are charged to cost of sales.
Leases	Leases The Company adopted the new leasing standards using the modified retrospective transition approach, as of January 1, 2019, with no restatement of prior periods. Upon adoption all operating lease commitments with a lease term greater than 12 months that were previously assessed under the prior lease guidance, were recognized as right-of-use assets and liabilities, on a discounted basis on the balance sheet. Leases with an initial term of 12 months or less are not recorded on the balance sheet. Certain lease agreements include rental payments that are adjusted periodically for inflation or other variables. The leases are initially measured using the projected payments adjusted for the index or rate in effect at the commencement date. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance and other expenses, which are generally referred to as non-lease components. Variable non-lease components are not measured as part of the right-of-use asset and liability. Only when lease components and their associated non-lease components are fixed are they accounted for as a single lease component and are recognized as part of a right-of-use asset and liability. Some leases contain clauses for renewal at the Company’s option with renewal terms that generally extend the lease term from 1 to 5 years. Certain lease agreements contain options to purchase the leased property and options to terminate the lease. Payments to be made in option periods are recognized as part of the right-of-use lease assets and lease liabilities when it is reasonably certain that the option to extend the lease will be exercised or the option to terminate the lease will not be exercised, or is not at the Company’s option. The Company determines whether the reasonably certain threshold is met by considering contract-, asset-, market-, and entity-based factors. A portfolio approach is applied to certain lease contracts with similar characteristics. The Company’s lease agreements do not contain any significant residual value guarantees or material restrictive covenants imposed by the leases.
Accounts Receivable	Accounts Receivable Accounts receivable are initially recorded at the contractual amount owed by the customer or based on expected payments from the insurance provider, hospital or patient. Allowances for doubtful accounts are established when the facts and circumstances indicate that a receivable may not be collectible. Potential credit risk exposure has been evaluated for the Company’s accounts receivable in accordance with ASC 326, Financial Instruments - Credit Losses.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are initially measured and recognized at acquisition cost, including any directly attributable cost of preparing the asset for its intended use or, in the case of assets acquired in a business combination, at fair value as at the date of the combination. After initial measurement, property, plant and equipment are carried at cost less accumulated depreciation and impairment. Repair and maintenance costs of property, plant and equipment are expensed as incurred. The depreciable value of property, plant and equipment, net of any residual value, is depreciated on a straight line basis over the useful life of the asset. The useful life of an asset is usually equivalent to its economic life. The useful lives of property, plant and equipment are as follows: • Machinery and Equipment: 5 years • Furniture, fixtures, and office equipment: 3 to 5 years • Computer equipment and software: 3 years • Building improvements and leasehold improvements: Shorter of the remaining life of the lease or 10 years The costs of assets retired or otherwise disposed of and the accumulated depreciation thereon are removed from the accounts, with any gain or loss realized upon sale or disposal credited or charged to operations.
Revenue Recognition and Net Product Sales	Revenue Recognition and Net Product Sales MACI, MACI Biopsy Kits, Epicel and NexoBrid The Company recognizes product revenue from sales to a customer (whether a distributor, or hospital ) following the five step model in ASC 606: (i) identify contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenues when (or as) the Company satisfies the performance obligation. Under this revenue standard, the Company recognizes revenue when its customer obtains control of the promised goods, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods. There are no contractual rights of returns, refunds or similar obligations related to MACI, kits, Epicel or NexoBrid as of December 31, 2020; however, in certain limited cases the Company will accept a product return if a surgery is canceled. Revenue is not recognized in certain canceled cases. For MACI, MACI kits and Epicel there are no variable pricing arrangements related to warranties or rebates offered to customers. The majority of orders are due within 60 to 90 days of delivery. Shipping and handling fees are included as a component of revenue. The Company recognizes any commission fees as an expense when incurred. These fees are included in selling, general, and administrative expenses. NexoBrid The U.S. Biomedical Advanced Research and Development Authority (BARDA) has committed to procure NexoBrid from MediWound, under which MediWound will manufacture and supply NexoBrid on a unit price basis, which may be increased pursuant to the terms of the agreement. The Company does not hold a direct contract or distribution agreement with BARDA, or take title to the product. The Company recognizes income from sales of NexoBrid to BARDA upon delivery, at which time BARDA is in control of the product. The Company does not control the specified goods or services before they are transferred to the customer. MediWound has promised to provide the goods to BARDA and has completed all significant compliance aspects of being a contractor for BARDA and continue to be responsible for all compliance. The Company records the NexoBrid revenue based on a specified percentage of the gross profit MediWound recognizes on the sale in accordance with the license agreement.
Research and Development Expense	Research and Development Expense Research and development activities represent a significant part of the Company’s business. These expenditures relate to the development of new products, improvement of existing products, technical support of products and compliance with governmental regulations for the protection of consumers and patients. Research and development expenses are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation The Company’s accounting for stock-based compensation requires it to determine the fair value of common stock issued in the form of stock option awards and restricted stock units. The Company uses the value of its common stock at the date of the grant in the calculation of the fair value of its share-based awards. The fair value of restricted stock units held by the employees is determined based on the fair value of the Company’s common stock on the date of the grant. The fair value of stock options held by the employees is determined using a Black-Scholes option valuation method, which is a valuation technique that is acceptable for share-based payment accounting. Key assumptions in determining fair value include volatility, risk-free interest rate, dividend yield and expected term. The assumptions used in calculating the fair value of stock options represent the Company’s best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the stock-based compensation expense could be materially different in the future. In addition, the Company estimates the expected forfeiture rate and only recognize expense for those stock options expected to vest over the service period. The estimated forfeiture rate considers the historical experience of the Company’s stock-based awards. If the actual forfeiture rate is different from the estimate, expense is adjusted accordingly. For certain non-employee consultants, stock option awards continue to vest post-termination. The Company also has an Employee Stock Purchase Plan (ESPP) which is a compensatory plan. Compensation expense is recorded based on the fair value of the purchase options at the grant date, which corresponds to the first day of each purchase period, and is amortized over the purchase period.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is the change in stockholders’ equity during a period arising from any gain or loss unrealized related to the Company’s investments.
Income Taxes	Income Taxes Deferred tax assets are recognized for deductible temporary differences and tax credit carryforwards and deferred tax liabilities are recognized for taxable temporary differences. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized based on the weight of available evidence, that a portion or all of the deferred tax assets will not be realized. When evaluating the realizability of the deferred tax assets, all evidence, both positive and negative, is considered. Items considered when evaluating the need for a valuation allowance include the ability to carry back losses, future reversals of existing temporary differences, tax planning strategies, and expectations of future earnings. The Company records uncertain tax positions in the consolidated financial statements only if it is more likely than not that the uncertain tax position will be sustained upon examination by the taxing authorities. The Company records interest and penalties related to uncertain tax positions in income tax expense.
Net Income (Loss) Per Share Attributable to Common Shareholders	Net Income (Loss) Per Share Attributable to Common Shareholders Basic and diluted earnings (loss) per share is calculated using the two-class method. Basic earnings (loss) per share which is based on an earnings allocation formula that determines earnings (loss) per share for the holders of the Company’s common shares. There were no undeclared dividends for the year ended December 31, 2020 or 2019. Diluted earnings (loss) per share includes convertible securities or common equivalent share (stock options and warrants) in addition to the Company’s common shares. Common equivalent shares and treasury stock are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.
Financial Instruments	Financial Instruments The Company’s financial instruments include receivables for which the current carrying amounts approximate market value, based upon their short-term nature and marketable debt securities which are classified as available-for-sale and carried at fair value on a settlement date basis.
Warrants	Warrants
Recent Accounting Pronouncements	Recent Accounting Pronouncements Measuring Credit Losses on Financial Instruments The FASB issued updated guidance on measuring credit losses on financial instruments. The guidance removes the thresholds that companies apply to measure credit losses on financial instruments measured at amortized cost, such as loans, receivables, and held-to-maturity debt securities. Prior to the updated guidance, credit losses were recognized when it was probable that the loss had been incurred. The revised guidance removes all recognition thresholds and requires companies to recognize an allowance for credit losses for the difference between the amortized cost basis of a financial instrument and the amount of amortized cost that a company expected to collect over the instrument’s contractual life. The Accounting Standard Update (ASU) 2016-13 , Financial Instruments-Credit Losses (Topic 326) , became effective for the Company January 1, 2020. See note 4 and note 8 for further discussion. Fair Value Measurement Disclosure The FASB issued updated guidance through ASU 2018-13 , Fair Value Measurement (Topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. The revised guidance created a more consistent disclosure framework that increased clarity and removed, modified and added certain fair value disclosures to improve the effectiveness of the Company’s disclosures in the notes of the Consolidated Financial Statements. This guidance became effective for the Company January 1, 2020 and had no impact on its Consolidated Financial Statements. Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12 , Simplifying the Accounting for Income Taxes (ASC 740). The ASU enhances and simplifies various aspects of the income tax accounting guidance in ASC 740, including requirements related to hybrid tax regimes, the tax basis step-up in goodwill obtained in a transaction that is not a business combination, separate financial statements of entities not subject to tax, the intra-period tax allocation exception to the incremental approach, ownership changes in investments, changes from a subsidiary to an equity method investment, interim-period accounting for enacted changes in tax law, and the year-to-date loss limitation in interim-period tax accounting. This guidance is effective for the Company for annual and interim periods beginning after December 31, 2020; however, early adoption is permitted. The Company is currently in the process of evaluating the impact on its Consolidated Financial Statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Supplementary cash flows information	The following table presents certain supplementary cash flows information for the years ended December 31, 2020, 2019 and 2018: Year Ended December 31, (In thousands) 2020 2019 2018 Supplementary Cash Flows information: Non-cash information: Warrants exercised for common stock $ — $ 104 $ 3,538 Right-of-use asset and lease liability recognized 29,573 2,599 — Additions to property and equipment included in accounts payable 531 217 606 Cash information: Interest paid (net of interest capitalized) $ 6 $ 8 $ 2,230 Year Ended December 31, (In thousands) 2020 2019 2018 Reconciliation of cash, cash equivalents, and restricted cash reported in the statement of financial position: Cash and cash equivalents $ 33,620 $ 26,889 $ 18,286 Restricted cash, included in other long-term assets 211 89 — Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 33,831 $ 26,978 $ 18,286

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Disaggregation of Revenue	The following table and description below shows the products from which the Company generated its revenue: Year Ended December 31, Revenue by product (in thousands) 2020 2019 2018 MACI and Carticel implants and kits Implants based on contracted rate sold through a specialty pharmacy (a) $ 57,593 $ 56,185 $ 42,926 Implants subject to third-party reimbursement sold through a specialty pharmacy (b) 16,320 17,076 8,621 Implants sold direct based on contracted rates (c) 15,144 13,933 12,122 Implants sold direct subject to third-party reimbursement (d) 2,754 1,529 2,257 Biopsy kits - direct bill 1,908 2,243 1,997 Change in estimates related to prior periods (e) 713 654 (182) Epicel Direct bill (hospital) 27,536 26,230 23,116 NexoBrid (f) 2,211 — — Total revenue $ 124,179 $ 117,850 $ 90,857 (a) Represents implants sold through Orsini and AllCare whereby such specialty pharmacies have a direct contract with the underlying insurance provider. The amount of reimbursement is based on contracted rates at the time of sale supported by the pharmacy's direct contracts. (b) Represents implants sold through Orsini or AllCare whereby such specialty pharmacy does not have a direct contract with the underlying payer. The amount of reimbursement is established based on a payer or state fee schedule and/or payer history. (c) Represents implants sold directly from the Company to the facility based on a contract and known price agreed upon prior to the surgery date. Also represents direct sales under a contract to specialty distributor DMS. (d) Represents implants sold directly from the Company to the facility based on a contract and known price agreed upon prior to the surgery date. The payment terms are subject to third-party reimbursement from an underlying insurance provider. (e) Primarily represents changes in estimates related to implants sold through Orsini or AllCare in which such specialty pharmacy does not have a direct contract with the underlying payer. The initial estimate of the amount of reimbursement is established based on a payer or state fee schedule and/or payer history. The change in estimates is a result of additional information, changes in collection expectations or actual cash collections received in the current period. (f) Represents revenue based on a percentage of gross profits for sales of NexoBrid to BARDA, pursuant to the license agreement between the Company and MediWound.

Selected Balance Sheet Compon_2

Selected Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of inventory	Inventory as of December 31, 2020 and 2019: (In thousands) 2020 2019 Raw materials $ 8,775 $ 6,085 Work-in-process 537 541 Finished goods 44 190 Inventory $ 9,356 $ 6,816
Schedule of property and equipment, net	Property and Equipment, net as of December 31, 2020 and 2019: (In thousands) 2020 2019 Machinery and equipment $ 3,672 $ 3,152 Furniture, fixtures and office equipment 809 775 Computer equipment and software 6,846 6,174 Leasehold improvements 5,560 5,256 Construction in process 2,021 859 Financing right-of-use lease 111 148 Total property and equipment, gross 19,019 16,364 Less accumulated depreciation (11,386) (9,220) $ 7,633 $ 7,144
Schedule of accrued expenses	Accrued Expenses as of December 31, 2020 and 2019: (In thousands) 2020 2019 Bonus related compensation $ 5,721 $ 5,116 Employee related accruals 3,482 1,785 Other accrued expenses 2,090 1,047 Accrued expenses $ 11,293 $ 7,948

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Total leased assets and liabilities	Total leased assets and liabilities classified on the balance sheet as of December 31, 2020 and 2019 are as follows: December 31, (In thousands) Classification 2020 2019 Assets Operating Right-of-use assets $ 50,105 $ 25,103 Finance Property and equipment, net 111 148 $ 50,216 $ 25,251 Liabilities Current Operating Current portion of operating lease liabilities $ 4,394 $ 5,461 Finance Other liabilities 41 41 $ 4,435 $ 5,502 Non-current Operating Operating lease liabilities $ 48,789 $ 22,242 Finance Other long-term liabilities 76 110 $ 48,865 $ 22,352
Maturity of lease liabilities	Maturity of lease liabilities as of December 31, 2020 are as follows: (In thousands) Operating Leases Finance Leases Total 2021 $ 4,394 $ 41 $ 4,435 2022 4,177 41 4,218 2023 6,973 41 7,014 2024 6,934 — 6,934 2025 6,340 — 6,340 more than 5 years 43,507 — 43,507 Total lease payments $ 72,325 $ 123 $ 72,448 Less: interest (19,142) (7) (19,149) Present value of lease liabilities $ 53,183 $ 116 $ 53,299
Maturity of lease liabilities	Maturity of lease liabilities as of December 31, 2020 are as follows: (In thousands) Operating Leases Finance Leases Total 2021 $ 4,394 $ 41 $ 4,435 2022 4,177 41 4,218 2023 6,973 41 7,014 2024 6,934 — 6,934 2025 6,340 — 6,340 more than 5 years 43,507 — 43,507 Total lease payments $ 72,325 $ 123 $ 72,448 Less: interest (19,142) (7) (19,149) Present value of lease liabilities $ 53,183 $ 116 $ 53,299
Lease term and discount rate	Lease terms and discount rates as of December 31, 2020 are as follows: December 31, 2020 2019 Weighted-average remaining lease term (years) Operating leases 10.6 6.8 Finance leases 2.5 3.5 Weighted-average discount rate Operating leases 5.42% 9.44% Finance leases 5.00% 5.00%

Cash Equivalents and Investme_2

Cash Equivalents and Investments (Tables)	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Schedule of fair value of securities, not including cash	The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2020 and December 31, 2019: December 31, 2020 Gross Unrealized Amortized Cost Gains Losses Credit Losses Estimated Fair Value Money market funds $ 3,698 $ — $ — $ — $ 3,698 Commercial paper 8,993 1 — — 8,994 Corporate notes 35,917 — — (6) 35,911 U.S. government securities 12,828 14 — — 12,842 U.S. government agency bonds 5,000 1 — — 5,001 U.S. asset-backed securities 3,534 4 — — 3,538 $ 69,970 $ 20 $ — $ (6) $ 69,984 Classified as: Cash equivalents $ 3,698 Short-term investments 42,187 Long-term investments 24,099 $ 69,984 December 31, 2019 Gross Unrealized (In thousands) Amortized Cost Gains Losses Estimated Fair Value Money market funds $ 5,381 $ — $ — $ 5,381 Commercial paper 11,892 — — 11,892 Corporate notes 18,369 11 — 18,380 U.S. government securities 11,291 4 — 11,295 U.S. asset-backed securities 10,503 6 — 10,509 $ 57,436 $ 21 $ — $ 57,457 Classified as: Cash equivalents $ 5,381 Short-term investments 42,829 Long-term investments 9,247 $ 57,457

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of fair value assumptions	The fair value of each service-based stock option grant for the reported periods is estimated on the date of the grant using the Black-Scholes option-pricing model using the weighted-average assumptions noted in the following table: Year Ended December 31, Service-Based Stock Options 2020 2019 2018 Expected dividend rate —% —% —% Expected stock price volatility 71.1 - 78.7% 77.9 - 85.5% 82.3 – 88.3% Risk-free interest rate 0.33 - 1.7% 1.4 - 2.7% 2.4 – 3.1% Expected life (years) 5.3 - 6.3 5.3 - 6.3 5.3 - 6.3
Summary of activity for service-based stock options	The following table summarizes the activity for service-based stock options for the indicated periods: Service-Based Stock Options Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (Thousands) Outstanding at December 31, 2019 5,052,950 $ 10.35 7.7 $ 37,974 Granted 1,356,540 13.42 Exercised (790,532) 7.06 Expired (29,115) 21.38 Forfeited (353,799) 13.82 Outstanding at December 31, 2020 5,236,044 $ 11.34 7.3 $ 102,654 Exercisable at December 31, 2020 2,885,729 $ 9.16 6.4 $ 63,037
Summary of activity for restricted stock awards	The following table summarizes the activity for restricted stock awards for the indicated periods: Restricted Stock Units Number of Restricted Stock Awards Weighted-Average Grant Date Fair Value Weighted-Average Term Aggregate Intrinsic Value Outstanding at December 31, 2019 157,030 $ 17.80 1.6 $ 2,732 Granted 196,836 11.41 2,246 Vested (46,712) 17.59 Forfeited (36,515) 15.00 Unvested at December 31, 2020 270,639 $ 13.57 1.4 $ 8,357
Schedule of non-cash stock-based compensation expense	Non-cash stock-based compensation expense (employee stock purchase plan, service-based stock options and restricted stock units) included in cost of goods sold, research and development expenses and selling, general and administrative expenses is summarized in the following table: Years Ended December 31, (in thousands) 2020 2019 2018 Cost of goods sold $ 1,949 $ 2,029 $ 1,015 Research and development 1,884 2,428 1,672 Selling, general and administrative 10,010 8,722 4,536 Total non-cash stock-based compensation expense $ 13,843 $ 13,179 $ 7,223

Net Income (Loss) Per Common _2

Net Income (Loss) Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of net loss attributable to common shareholders and share data used in the basic and diluted earnings per share computations using the two class method	The following reflects the net income (loss) attributable to common shareholders and share data used in the basic and diluted earnings per share computations using the two class method: Year Ended December 31, (Amounts in thousands, except per share amounts) 2020 2019 2018 Numerator: Net income (loss) $ 2,864 $ (9,665) $ (8,137) Denominator: Weighted-average common shares outstanding (basic) 45,221 44,180 40,242 Net income (loss) per share attributable to common shareholders (basic) $ 0.06 $ (0.22) $ (0.20) Weighted-average common shares outstanding (diluted) 47,282 44,180 40,242 Net income (loss) per share attributable to common shareholders (diluted) $ 0.06 $ (0.22) $ (0.20) Anti-dilutive shares excluded from the calculation of diluted earnings per share (a) (amounts in millions): Stock options 2.2 5.1 4.8 Restricted stock unit awards — 0.2 — (a) Common equivalent shares are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of valuation of the Company's investments and financial instruments that are measured at fair value on a recurring basis	The following table summarizes the valuation of the Company’s financial instruments that are measured at fair value on a recurring basis: December 31, 2020 December 31, 2019 Fair value measurement category Fair value measurement category (In thousands) Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Assets: Money market funds $ 3,698 $ 3,698 $ — $ — $ 5,381 $ 5,381 $ — $ — Commercial paper 8,994 — 8,994 — 11,892 — 11,892 — Corporate notes 35,911 — 35,911 — 18,380 — 18,380 — U.S. government securities 12,842 — 12,842 — 11,295 — 11,295 — U.S. government agency bonds 5,001 — 5,001 — — — — — U.S. asset-backed securities 3,538 — 3,538 — 10,509 — 10,509 — $ 69,984 $ 3,698 $ 66,286 $ — $ 57,457 $ 5,381 $ 52,076 $ —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of income (loss) before income taxes for U.S. and non-U.S. operations	Loss before income taxes for U.S and non-U.S operations was as follows: Year Ended December 31, 2020 2019 2018 U.S. income (loss) $ 2,767 $ (9,632) $ (8,056) Non U.S. income (loss) 97 (33) (81) $ 2,864 $ (9,665) $ (8,137)
Schedule of reconciliation of income taxes computed using the federal statutory rate to the taxes reported in consolidated statements of operations	A reconciliation of income taxes computed using the federal statutory rate to the taxes reported in the consolidated statements of operations is as follows: Year Ended December 31, (In thousands) 2020 2019 2018 Income (loss) before income taxes $ 2,864 $ (9,665) $ (8,137) Federal statutory rate 21 % 21 % 21 % Taxes computed at federal statutory rate 601 (2,030) (1,709) State and local income taxes 200 (484) (385) Nondeductible share-based compensation 437 (1,329) (605) Federal and state rate change 249 (164) 839 Research and orphan drug credits (8,827) — — Other 132 (49) 172 Change in valuation allowance 7,388 4,056 1,688 Reported income taxes $ 180 $ — $ —
Schedule of deferred tax assets	Deferred tax assets (liabilities) consist of the following: Year Ended December 31, (In thousands) 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 8,411 $ 10,542 Employee benefits and stock compensation 5,692 4,329 Research and development costs 6,411 7,851 Intangible assets 3,279 4,350 Operating lease liability 13,687 7,245 Inventory reserve 3,813 3,303 Tax credit carryforward 10,085 — Other, net 38 119 Total deferred tax assets 51,416 37,739 Less: valuation allowance (37,379) (29,991) Total net deferred tax assets 14,037 7,748 Deferred tax liabilities: Right of use asset (13,463) (7,143) Fixed assets (574) (605) Total net deferred tax liabilities (14,037) (7,748) Net deferred tax assets and liabilities $ — $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum purchase commitments related to contractual obligations	Future minimum purchase commitments related to our contractual obligations are as follows: Payments Due by Period Contractual Obligations (in thousands) Total 2021 2022 2023 2024 2025 More than 5 Years Purchase commitments $ 7,864 $ 7,182 $ 682 $ — $ — $ — $ —

Supplementary Quarterly Finan_2

Supplementary Quarterly Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	In thousands, except per share data First Quarter Second Quarter Third Quarter Fourth Quarter Year 2020 Revenues $ 26,678 $ 20,014 $ 32,258 $ 45,229 $ 124,179 Gross profit 16,756 11,354 22,471 33,647 84,228 Income (Loss) from operations (5,076) (8,358) 3,517 12,289 2,372 Net Income (loss) (4,705) (8,269) 3,618 12,220 2,864 Net Income (loss) per share (Basic) (0.10) (0.18) 0.08 0.27 0.06 Net Income (loss) per share (Diluted) (0.10) (0.18) 0.08 0.25 0.06 2019 Revenues $ 21,810 $ 26,151 $ 30,499 $ 39,390 $ 117,850 Gross profit 13,170 17,129 21,175 28,805 80,279 Income (Loss) from operations (3,358) (20,200) 3,097 9,210 (11,251) Net Income (loss) (2,844) (19,792) 3,470 9,501 (9,665) Net Income (loss) per share (Basic) (0.07) (0.45) 0.08 0.21 (0.22) Net Income (loss) per share (Diluted) (0.07) (0.45) 0.07 0.20 (0.22)

Organization (Details)

Organization (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | segment									1
Accumulated deficit	$ 375,815				$ 378,679				$ 375,815	$ 378,679
Net income	(12,220)	$ (3,618)	$ 8,269	$ 4,705	(9,501)	$ (3,470)	$ 19,792	$ 2,844	(2,864)	9,665	$ 8,137
Cash and cash equivalents	33,620				$ 26,889				33,620	$ 26,889	$ 18,286
Short term investments	$ 66,300								$ 66,300

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Supplementary cash flows information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Non-cash information:
Warrants exercised for common stock	$ 0	$ 104	$ 3,538
Right-of-use asset and lease liability recognized	29,573	2,599	0
Additions to property and equipment included in accounts payable	531	217	606
Cash information:
Interest paid (net of interest capitalized)	6	8	2,230
Cash and cash equivalents	33,620	26,889	18,286
Restricted cash, included in other long-term assets	211	89	0
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 33,831	$ 26,978	$ 18,286	$ 26,862

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment
Warrants outstanding (in shares)	0	0
Minimum
Property, Plant and Equipment
Duration of lease renewal terms	1 year
Maximum
Property, Plant and Equipment
Duration of lease renewal terms	5 years
Machinery and Equipment
Property, Plant and Equipment
Useful lives (in years)	5 years
Furniture, fixtures and office equipment | Minimum
Property, Plant and Equipment
Useful lives (in years)	3 years
Furniture, fixtures and office equipment | Maximum
Property, Plant and Equipment
Useful lives (in years)	5 years
Computer equipment and software
Property, Plant and Equipment
Useful lives (in years)	3 years
Building improvements and leasehold improvements
Property, Plant and Equipment
Useful lives (in years)	10 years

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONCENTRATION
Allowance for doubtful accounts	$ 5,300	$ 3,900
Change in estimate of uncollectible (percent)	0.50%
Change in revenue recognized due to 0.5% change in uncollectible percentage	$ 300
Increase (decrease) to revenues	121,968	117,850	$ 90,857
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
CONCENTRATION
Increase (decrease) to revenues	$ 713	$ 654	$ (182)

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Product sales, net									$ 121,968	$ 117,850	$ 90,857
Revenues	$ 45,229	$ 32,258	$ 20,014	$ 26,678	$ 39,390	$ 30,499	$ 26,151	$ 21,810	124,179	117,850	90,857
Other revenue									2,211	0	0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Product sales, net									713	654	(182)
NexoBrid
Disaggregation of Revenue [Line Items]
Other revenue									2,211	0	0
Through Intermediary | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net									57,593	56,185	42,926
Through Intermediary | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net									16,320	17,076	8,621
Directly to consumer | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net									15,144	13,933	12,122
Directly to consumer | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net									2,754	1,529	2,257
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net									1,908	2,243	1,997
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net									$ 27,536	$ 26,230	$ 23,116

Revenue - Schedules of concentr

Revenue - Schedules of concentration of risk (Details)	12 Months Ended
	Dec. 31, 2018
Revenue Concentration | Customer concentration | MACI
Product Information [Line Items]
Concentration risk (as a percent)	16.00%

Selected Balance Sheet Compon_3

Selected Balance Sheet Components - Schedule of inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory:
Raw materials	$ 8,775	$ 6,085
Work-in-process	537	541
Finished goods	44	190
Inventory	$ 9,356	$ 6,816

Selected Balance Sheet Compon_4

Selected Balance Sheet Components - Schedule of property and equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property and equipment, net:
Financing right-of-use lease	$ 111	$ 148
Total property and equipment, gross	19,019	16,364
Less accumulated depreciation	(11,386)	(9,220)
Total property and equipment, net	7,633	7,144
Depreciation expense	2,400	1,700	$ 1,400
Machinery and equipment
Property and equipment, net:
Total property and equipment, gross	3,672	3,152
Furniture, fixtures and office equipment
Property and equipment, net:
Total property and equipment, gross	809	775
Computer equipment and software
Property and equipment, net:
Total property and equipment, gross	6,846	6,174
Leasehold improvements
Property and equipment, net:
Total property and equipment, gross	5,560	5,256
Construction in process
Property and equipment, net:
Total property and equipment, gross	$ 2,021	$ 859

Selected Balance Sheet Compon_5

Selected Balance Sheet Components - Schedule of accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued expenses
Bonus related compensation	$ 5,721	$ 5,116
Employee related accruals	3,482	1,785
Other accrued expenses	2,090	1,047
Accrued expenses	$ 11,293	$ 7,948

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Dec. 19, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Repayments of debt		$ 0	$ 0	$ 17,532
Loss on extinguishment of debt		$ 0	$ 0	838
SVB and MidCap | Term loan
Debt Instrument [Line Items]
Repayments of debt	$ 17,100
Pre-payment premium (as a percent)	1.50%
Payment for debt extinguishment or debt prepayment cost	$ 200
Stated percentage for final payment (as a percent)	3.60%
Debt instrument final payment	$ 500
Loss on extinguishment of debt				$ 800

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	Oct. 21, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Short-term lease costs (less than)		$ 0.1	$ 0.1
Operating lease expense		6.3	5.4
Rent expense				$ 5.2
Finance lease expense		0.1	0.1	$ 0.1
Measurement of lease liability		5.8	$ 5
Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Tenant improvement allowance		$ 4.3
Minimum | Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Monthly contractual lease payments	$ 0.4
Maximum | Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Monthly contractual lease payments	$ 0.6

Leases - Assets And Liabilities

Leases - Assets And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating	$ 50,105	$ 25,103
Finance	111	148
Right-of-use assets	$ 50,216	$ 25,251
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Current
Operating	$ 4,394	$ 5,461
Finance	41	41
Lease liability current	4,435	5,502
Non-current
Operating	48,789	22,242
Finance	76	110
Lease liability noncurrent	$ 48,865	$ 22,352
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent

Leases - Maturities of lease li

Leases - Maturities of lease liabilities (Details) $ in Thousands	Dec. 31, 2020USD ($)
Operating Leases
2021	$ 4,394
2022	4,177
2023	6,973
2024	6,934
2025	6,340
more than 5 years	43,507
Total lease payments	72,325
Less: interest	(19,142)
Present value of lease liabilities	53,183
Finance Leases
2021	41
2022	41
2023	41
2024	0
2025	0
more than 5 years	0
Total lease payments	123
Less: interest	(7)
Present value of lease liabilities	116
2021	4,435
2022	4,218
2023	7,014
2024	6,934
2025	6,340
more than 5 years	43,507
Total lease payments	72,448
Less: interest	(19,149)
Present value of lease liabilities	$ 53,299

Leases - Lease term and discoun

Leases - Lease term and discount rate (Details)	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Weighted-average remaining lease term - Operating lease term	10 years 7 months 6 days	6 years 9 months 18 days
Weighted-average remaining lease term - Finance lease term	2 years 6 months	3 years 6 months
Weighted-average discount rate - Operating lease discount rate	5.42%	9.44%
Weighted-average discount rate - Finance lease discount rate	5.00%	5.00%

Cash Equivalents and Investme_3

Cash Equivalents and Investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Amortized Cost	$ 69,970,000	$ 57,436,000
Gains	20,000	21,000
Losses	0	0
Credit Losses	(6,000)
Estimated Fair Value	69,984,000	57,457,000
Asset impairment charges	0
Cash equivalents
Marketable Securities [Line Items]
Estimated Fair Value	3,698,000	5,381,000
Short-term investments
Marketable Securities [Line Items]
Estimated Fair Value	42,187,000	42,829,000
Long-term investments
Marketable Securities [Line Items]
Estimated Fair Value	24,099,000	9,247,000
Money market funds
Marketable Securities [Line Items]
Amortized Cost	3,698,000	5,381,000
Gains	0	0
Losses	0	0
Credit Losses	0
Estimated Fair Value	3,698,000	5,381,000
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	8,993,000	11,892,000
Gains	1,000	0
Losses	0	0
Credit Losses	0
Estimated Fair Value	8,994,000	11,892,000
Corporate notes
Marketable Securities [Line Items]
Amortized Cost	35,917,000	18,369,000
Gains	0	11,000
Losses	0	0
Credit Losses	(6,000)
Estimated Fair Value	35,911,000	18,380,000
U.S. government securities
Marketable Securities [Line Items]
Amortized Cost	12,828,000	11,291,000
Gains	14,000	4,000
Losses	0	0
Credit Losses	0
Estimated Fair Value	12,842,000	11,295,000
U.S. government agency bonds
Marketable Securities [Line Items]
Amortized Cost	5,000,000
Gains	1,000
Losses	0
Credit Losses	0
Estimated Fair Value	5,001,000
U.S. asset-backed securities
Marketable Securities [Line Items]
Amortized Cost	3,534,000	10,503,000
Gains	4,000	6,000
Losses	0	0
Credit Losses	0
Estimated Fair Value	$ 3,538,000	$ 10,509,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended			72 Months Ended
	Jan. 31, 2021	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Stock-Based Compensation
Shares issued under the Employee Stock Purchase Plan (in shares)			$ 1,050	$ 932	$ 656
Granted (in shares)			1,356,540
Expected to vest (in shares)		4,949,912	4,949,912			4,949,912
Total unrecognized compensation cost		$ 13,100	$ 13,100			$ 13,100
Intrinsic value of stock options exercised			$ 10,500	16,100	11,400
Stock options
Stock-Based Compensation
Expiration period			10 years
Vesting period			4 years
Stock-based compensation expense			$ 12,100	$ 11,800	$ 6,900
Granted (in shares)			1,356,540
Weighted average grant-date fair value (in dollars per share)			$ 8.86	$ 12.62	$ 6.96
Weighted average period over which unrecognized compensation is expected to be recognized			2 years 8 months 12 days
Employee stock
Stock-Based Compensation
Common stock available for issuance (in shares)		1,000,000	1,000,000			1,000,000
Common stock granted since inception (in shares)						708,452
Shares issued under the Employee Stock Purchase Plan (in shares)		$ 200
Stock-based compensation expense			$ 400	$ 300	$ 300
Restricted stock unit awards
Stock-Based Compensation
Vesting period			4 years
Stock-based compensation expense			$ 1,400	$ 1,000
Weighted average period over which unrecognized compensation is expected to be recognized			2 years 8 months 12 days	3 years 1 month 6 days
Vested (shares)			46,712	0
Shares withheld for payment of tax (in shares)			13,872
Grant-date fair value of restricted stock units granted			$ 2,246	$ 3,300
Unrecognized compensation cost		$ 2,100	2,100	$ 1,800		$ 2,100
Fair value of vested awards			$ 600
Subsequent event | Employee stock
Stock-Based Compensation
Shares purchased during period (in shares)	14,954
Prior Plans
Stock-Based Compensation
Awards available for future grant under the Plan (in shares)		0	0			0
Omnibus Incentive Plan 2019
Stock-Based Compensation
Awards available for future grant under the Plan (in shares)		4,544,084	4,544,084			4,544,084
Nonemployee directors | Stock options
Stock-Based Compensation
Expiration period			10 years
Vesting period			1 year
Granted (in shares)			78,750
Nonemployee directors | Restricted stock unit awards
Stock-Based Compensation
Vested (shares)			10,500
Shares withheld for payment of tax (in shares)			0

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of fair value assumptions (Details) - Stock options	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock-Based Compensation
Expected dividend rate	0.00%	0.00%	0.00%
Minimum
Stock-Based Compensation
Expected stock price volatility	71.10%	77.90%	82.30%
Risk-free interest rate	0.33%	1.40%	2.40%
Expected life (years)	5 years 3 months 18 days	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Stock-Based Compensation
Expected stock price volatility	78.70%	85.50%	88.30%
Risk-free interest rate	1.70%	2.70%	3.10%
Expected life (years)	6 years 3 months 18 days	6 years 3 months 18 days	6 years 3 months 18 days

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of activity for service-based stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Options
Outstanding at the beginning of the period (in shares)	5,052,950
Granted (in shares)	1,356,540
Exercised (in shares)	(790,532)
Expired (in shares)	(29,115)
Forfeited (in shares)	(353,799)
Outstanding at the end of the period (in shares)	5,236,044	5,052,950
Exercisable at the end of the period (in shares)	2,885,729
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 10.35
Granted (in dollars per share)	13.42
Exercised (in dollars per share)	7.06
Expired (in dollars per share)	21.38
Forfeited (in dollars per share)	13.82
Outstanding at the end of the period (in dollars per share)	11.34	$ 10.35
Exercisable at the end of the period (in dollars per share)	$ 9.16
Weighted Average Remaining Contractual Term
Outstanding	7 years 3 months 18 days	7 years 8 months 12 days
Exercisable at end of period	6 years 4 months 24 days
Aggregate Intrinsic Value
Outstanding	$ 102,654	$ 37,974
Exercisable at end of period	$ 63,037

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of restricted stock awards activity (Details) - Restricted stock unit awards - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Restricted Stock Awards
Outstanding at beginning of period (shares)	157,030
Granted (shares)	196,836
Vested (shares)	(46,712)	0
Forfeited (shares)	(36,515)
Unvested at end of period (shares)	270,639	157,030
Weighted-Average Grant Date Fair Value
Unvested at beginning of period (in usd per share)	$ 17.80
Granted (in usd per share)	11.41
Vested (in usd per share)	17.59
Forfeited (in usd per share)	15
Unvested at end of period (in usd per share)	$ 13.57	$ 17.80
Unvested - Weighted Average Term	1 year 4 months 24 days	1 year 7 months 6 days
Aggregate Intrinsic Value
Granted - Aggregate Intrinsic Value	$ 2,246	$ 3,300
Unvested - Aggregate Intrinsic Value	$ 8,357	$ 2,732

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of non-cash stock-based compensation expense (Details) - Employee stock purchase plan and service-based stock options - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	$ 13,843	$ 13,179	$ 7,223
Cost of goods sold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	1,949	2,029	1,015
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	1,884	2,428	1,672
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	$ 10,010	$ 8,722	$ 4,536

Net Income (Loss) Per Common _3

Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income (loss)	$ 12,220	$ 3,618	$ (8,269)	$ (4,705)	$ 9,501	$ 3,470	$ (19,792)	$ (2,844)	$ 2,864	$ (9,665)	$ (8,137)
Denominator for basic and diluted EPS:
Weighted average common shares outstanding (basic) (in shares)									45,221	44,180	40,242
Net income (loss) per share attributable to common shareholders (basic) (in USD per share)	$ 0.27	$ 0.08	$ (0.18)	$ (0.10)	$ 0.21	$ 0.08	$ (0.45)	$ (0.07)	$ 0.06	$ (0.22)	$ (0.20)
Weighted average common shares outstanding (diluted) (in shares)									47,282	44,180	40,242
Net income (loss) per share attributable to common shareholders (diluted) (in USD per share)	$ 0.25	$ 0.08	$ (0.18)	$ (0.10)	$ 0.20	$ 0.07	$ (0.45)	$ (0.07)	$ 0.06	$ (0.22)	$ (0.20)
Stock options
Denominator for basic and diluted EPS:
Anti-dilutive shares excluded from the calculation of diluted earnings per share (in shares)									2,200	5,100	4,800
Restricted stock unit awards
Denominator for basic and diluted EPS:
Anti-dilutive shares excluded from the calculation of diluted earnings per share (in shares)									0	200	0

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - Public Stock Offering $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended
	Jun. 30, 2018USD ($)$ / sharesshares
Shareholders' Equity
Public offering price per share (in dollars per share) | $ / shares	$ 13
Sale of stock, consideration received on transaction	$ 70.1
Commission and issuance cost	$ 4.7
Common Stock
Shareholders' Equity
Sale of stock, number of shares issued in transaction (in shares) | shares	5,750

Stock Purchase Warrants (Detail

Stock Purchase Warrants (Details)	12 Months Ended
	Dec. 31, 2019$ / sharesshares	Dec. 31, 2020shares
Stock Purchase Warrants
Exercise price (in dollars per share) | $ / shares	$ 4.27
Warrants outstanding (in shares)	0	0
Expected Dividend
Stock Purchase Warrants
Expected dividend rate (percent)		0
Common Stock
Stock Purchase Warrants
Conversion of preferred stock for common stock (in shares)	19,808

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	$ 69,984	$ 57,457
U.S. government securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	12,842	11,295
U.S. government agency bonds
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	5,001
Asset-backed Securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	3,538	10,509
Recurring
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	69,984	57,457
Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	3,698	5,381
Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	66,286	52,076
Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	0	0
Recurring | Commercial paper
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	8,994	11,892
Recurring | Commercial paper | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Commercial paper | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	8,994	11,892
Recurring | Commercial paper | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Corporate notes
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	35,911	18,380
Recurring | Corporate notes | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Corporate notes | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	35,911	18,380
Recurring | Corporate notes | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | U.S. government securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	12,842	11,295
Recurring | U.S. government securities | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | U.S. government securities | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	12,842	11,295
Recurring | U.S. government securities | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | U.S. government agency bonds
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	5,001	0
Recurring | U.S. government agency bonds | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | U.S. government agency bonds | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	5,001	0
Recurring | U.S. government agency bonds | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Asset-backed Securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	3,538	10,509
Recurring | Asset-backed Securities | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Asset-backed Securities | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	3,538	10,509
Recurring | Asset-backed Securities | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Recurring | Money market funds
Liabilities that are measured at fair value on a recurring basis
Money market funds	3,698	5,381
Recurring | Money market funds | Level 1
Liabilities that are measured at fair value on a recurring basis
Money market funds	3,698	5,381
Recurring | Money market funds | Level 2
Liabilities that are measured at fair value on a recurring basis
Money market funds	0	0
Recurring | Money market funds | Level 3
Liabilities that are measured at fair value on a recurring basis
Money market funds	$ 0	$ 0

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Loss before income taxes	$ 2,864	$ (9,665)	$ (8,137)
U.S. income (loss)
Operating Loss Carryforwards [Line Items]
Loss before income taxes	2,767	(9,632)	(8,056)
Non U.S. income (loss)
Operating Loss Carryforwards [Line Items]
Loss before income taxes	$ 97	$ (33)	$ (81)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of income taxes computed using the federal statutory rate to the taxes reported in consolidated statements of operations
Income (loss) before income taxes	$ 2,864	$ (9,665)	$ (8,137)
Federal statutory rate	21.00%	21.00%	21.00%
Taxes computed at federal statutory rate	$ 601	$ (2,030)	$ (1,709)
State and local income taxes	200	(484)	(385)
Nondeductible share-based compensation	437	(1,329)	(605)
Federal and state rate change	249	(164)	839
Research and orphan drug credits	(8,827)	0	0
Other	132	(49)	172
Change in valuation allowance	7,388	4,056	1,688
Reported income taxes	180	0	$ 0
Deferred tax assets
Net operating loss carryforwards	8,411	10,542
Employee benefits and stock compensation	5,692	4,329
Research and development costs	6,411	7,851
Intangible assets	3,279	4,350
Operating lease liability	13,687	7,245
Inventory reserve	3,813	3,303
Tax credit carryforward	10,085	0
Other, net	38	119
Total deferred tax assets	51,416	37,739
Less: valuation allowance	(37,379)	(29,991)
Total net deferred tax assets	14,037	7,748
Deferred tax liabilities:
Right of use asset	(13,463)	(7,143)
Fixed assets	(574)	(605)
Total net deferred tax liabilities	(14,037)	(7,748)
Net deferred tax assets and liabilities	$ 0	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Profit (loss) from operations	$ 12,289	$ 3,517	$ (8,358)	$ (5,076)	$ 9,210	$ 3,097	$ (20,200)	$ (3,358)	$ 2,372	$ (11,251)	$ (3,909)
Projected annual limitation on the use of the net operating losses that existed prior to September 17, 2014	800								800
General business tax credit carryforward	10,085				$ 0				10,085	0
Increase (decrease) in valuation allowance									7,400	$ 4,100
Federal | Internal Revenue Service
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	32,300								32,300
Profit (loss) from operations									(1,500)
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 21,300								$ 21,300

Employee Savings Plan (Details)

Employee Savings Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Contributions made under 401(k) savings plan	$ 0.8	$ 0.7	$ 0.6

NexoBrid License and Supply A_2

NexoBrid License and Supply Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Revenue recognized		$ 2,211	$ 0	$ 0
MediWound Ltd
Related Party Transaction [Line Items]
Consideration paid	$ 17,500
Payable	17,500
Contingent consideration	7,500
Max contingent consideration	125,000
Sales Initial milestone	$ 75,000

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2015	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Purchase obligation, annual commitment	$ 600	$ 7,182
Purchase obligation, renewal option, term	5 years
Purchase obligation, automatic renewal, term	5 years

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Oct. 31, 2015
Purchase commitments
Total	$ 7,864
2021	7,182	$ 600
2022	682
2023	0
2024	0
2025	0
More than 5 Years	$ 0

Supplementary Quarterly Finan_3

Supplementary Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 45,229	$ 32,258	$ 20,014	$ 26,678	$ 39,390	$ 30,499	$ 26,151	$ 21,810	$ 124,179	$ 117,850	$ 90,857
Gross profit	33,647	22,471	11,354	16,756	28,805	21,175	17,129	13,170	84,228	80,279	58,697
Income (Loss) from operations	12,289	3,517	(8,358)	(5,076)	9,210	3,097	(20,200)	(3,358)	2,372	(11,251)	(3,909)
Net Income (loss)	$ 12,220	$ 3,618	$ (8,269)	$ (4,705)	$ 9,501	$ 3,470	$ (19,792)	$ (2,844)	$ 2,864	$ (9,665)	$ (8,137)
Net income (loss) per share attributable to common shareholders (basic) (in USD per share)	$ 0.27	$ 0.08	$ (0.18)	$ (0.10)	$ 0.21	$ 0.08	$ (0.45)	$ (0.07)	$ 0.06	$ (0.22)	$ (0.20)
Net income (loss) per share (Diluted) (in USD per share)	$ 0.25	$ 0.08	$ (0.18)	$ (0.10)	$ 0.20	$ 0.07	$ (0.45)	$ (0.07)	$ 0.06	$ (0.22)	$ (0.20)