Vericel (VCEL) 10-Q 9 Nov 21 2021 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		46,815,257
Entity Central Index Key	0000887359
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 54,553	$ 33,620
Short-term investments	43,738	42,187
Accounts receivable (net of allowance for doubtful accounts of $40 and $143, respectively)	28,910	34,504
Inventory	13,059	9,356
Other current assets	4,686	3,893
Total current assets	144,946	123,560
Property and equipment, net	11,819	7,633
Restricted cash	211	211
Right-of-use assets	46,713	50,105
Long-term investments	20,235	24,099
Other long-term assets	219	0
Total assets	224,143	205,608
Current liabilities:
Accounts payable	5,575	6,755
Accrued expenses	10,932	11,293
Current portion of operating lease liabilities	2,280	4,394
Other liabilities	41	41
Total current liabilities	18,828	22,483
Operating lease liabilities	48,493	48,789
Other long-term liabilities	42	76
Total liabilities	67,363	71,348
COMMITMENTS AND CONTINGENCIES
Shareholders’ equity:
Common stock, no par value; shares authorized — 75,000; shares issued and outstanding 46,767 and 45,804, respectively	544,624	510,061
Accumulated other comprehensive income (loss)	(23)	14
Accumulated deficit	(387,821)	(375,815)
Total shareholders’ equity	156,780	134,260
Total liabilities and shareholders’ equity	$ 224,143	$ 205,608

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 40	$ 143
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	46,767,000	45,804,000
Common stock, shares outstanding (in shares)	46,767,000	45,804,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue, Product and Service [Extensible List]			Product [Member]
Product sales, net	$ 33,718	$ 31,020	$ 106,025	$ 77,712
Other revenue	788	1,238	2,568	1,238
Total revenue	34,506	32,258	$ 108,593	78,950
Cost, Product and Service [Extensible List]			Product [Member]
Cost of product sales	12,408	9,787	$ 36,600	28,369
Gross profit	22,098	22,471	71,993	50,581
Research and development	4,284	2,913	12,363	9,902
Selling, general and administrative	22,775	16,041	71,625	50,596
Total operating expenses	27,059	18,954	83,988	60,498
Income (loss) from operations	(4,961)	3,517	(11,995)	(9,917)
Other income (expense):
Interest income	44	121	163	574
Interest expense	(1)	(2)	(3)	(5)
Other income (expense)	(13)	(18)	45	(8)
Total other income	30	101	205	561
Income (loss) before tax expense	(4,931)	3,618	(11,790)	(9,356)
Tax expense	0	0	(215)	0
Net income (loss)	$ (4,931)	$ 3,618	$ (12,006)	$ (9,356)
Net income (loss) per common share (Basic) (in USD per share)	$ (0.11)	$ 0.08	$ (0.26)	$ (0.21)
Net income (loss) per common share (Diluted) (in USD per share)	$ (0.11)	$ 0.08	$ (0.26)	$ (0.21)
Weighted average common shares outstanding (Basic) (in shares)	46,669	45,272	46,355	45,112
Weighted average common shares outstanding (Diluted) (in shares)	46,669	47,314	46,355	45,112

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (4,931)	$ 3,618	$ (12,006)	$ (9,356)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	0	(68)	(37)	57
Comprehensive income (loss)	$ (4,931)	$ 3,550	$ (12,043)	$ (9,299)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019		44,864
Beginning balance at Dec. 31, 2019	$ 111,091	$ 489,749	$ 21	$ (378,679)
Increase (Decrease) in Shareholders' Equity
Net loss	(4,705)			(4,705)
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	3,768	$ 3,768
Stock option exercises (in shares)		57
Stock option exercises	196	$ 196
Shares issued under the Employee Stock Purchase Plan (in shares)		20
Shares issued under the Employee Stock Purchase Plan	224	$ 224
Issuance of stock upon restricted stock unit vesting (in shares)		36
Issuance of stock upon restricted stock unit vesting	0
Restricted stock withheld for employee tax remittance (in shares)		(14)
Restricted stock withheld for employee tax remittance	(163)	$ (163)
Unrealized gain (loss) on investments	41		41
Ending balance (in shares) at Mar. 31, 2020		44,963
Ending balance at Mar. 31, 2020	110,452	$ 493,774	62	(383,384)
Beginning balance (in shares) at Dec. 31, 2019		44,864
Beginning balance at Dec. 31, 2019	111,091	$ 489,749	21	(378,679)
Increase (Decrease) in Shareholders' Equity
Net loss	(9,356)
Unrealized gain (loss) on investments	57
Ending balance (in shares) at Sep. 30, 2020		45,315
Ending balance at Sep. 30, 2020	114,630	$ 502,587	78	(388,035)
Beginning balance (in shares) at Mar. 31, 2020		44,963
Beginning balance at Mar. 31, 2020	110,452	$ 493,774	62	(383,384)
Increase (Decrease) in Shareholders' Equity
Net loss	(8,269)			(8,269)
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	4,376	$ 4,376
Stock option exercises (in shares)		188
Stock option exercises	696	$ 696
Shares issued under the Employee Stock Purchase Plan (in shares)		32
Shares issued under the Employee Stock Purchase Plan	257	$ 257
Issuance of stock upon restricted stock unit vesting (in shares)		11
Issuance of stock upon restricted stock unit vesting	0
Unrealized gain (loss) on investments	84		84
Ending balance (in shares) at Jun. 30, 2020		45,194
Ending balance at Jun. 30, 2020	107,596	$ 499,103	146	(391,653)
Increase (Decrease) in Shareholders' Equity
Net loss	3,618			3,618
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	2,675	$ 2,675
Stock option exercises (in shares)		77
Stock option exercises	500	$ 500
Shares issued under the Employee Stock Purchase Plan (in shares)		44
Shares issued under the Employee Stock Purchase Plan	309	$ 309
Unrealized gain (loss) on investments	(68)		(68)
Ending balance (in shares) at Sep. 30, 2020		45,315
Ending balance at Sep. 30, 2020	114,630	$ 502,587	78	(388,035)
Beginning balance (in shares) at Dec. 31, 2020		45,804
Beginning balance at Dec. 31, 2020	134,260	$ 510,061	14	(375,815)
Increase (Decrease) in Shareholders' Equity
Net loss	(3,289)			(3,289)
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	7,019	$ 7,019
Stock option exercises (in shares)		359
Stock option exercises	3,532	$ 3,532
Shares issued under the Employee Stock Purchase Plan (in shares)		14
Shares issued under the Employee Stock Purchase Plan	249	$ 249
Issuance of stock upon restricted stock unit vesting (in shares)		76
Issuance of stock upon restricted stock unit vesting	0
Restricted stock withheld for employee tax remittance (in shares)		(28)
Restricted stock withheld for employee tax remittance	(1,501)	$ (1,501)
Unrealized gain (loss) on investments	(61)		(61)
Ending balance (in shares) at Mar. 31, 2021		46,225
Ending balance at Mar. 31, 2021	140,209	$ 519,360	(47)	(379,104)
Beginning balance (in shares) at Dec. 31, 2020		45,804
Beginning balance at Dec. 31, 2020	134,260	$ 510,061	14	(375,815)
Increase (Decrease) in Shareholders' Equity
Net loss	(12,006)
Unrealized gain (loss) on investments	(37)
Ending balance (in shares) at Sep. 30, 2021		46,767
Ending balance at Sep. 30, 2021	156,780	$ 544,624	(23)	(387,821)
Beginning balance (in shares) at Mar. 31, 2021		46,225
Beginning balance at Mar. 31, 2021	140,209	$ 519,360	(47)	(379,104)
Increase (Decrease) in Shareholders' Equity
Net loss	(3,786)			(3,786)
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	10,866	$ 10,866
Stock option exercises (in shares)		330
Stock option exercises	3,531	$ 3,531
Shares issued under the Employee Stock Purchase Plan (in shares)		13
Shares issued under the Employee Stock Purchase Plan	309	$ 309
Issuance of stock upon restricted stock unit vesting (in shares)		12
Issuance of stock upon restricted stock unit vesting	0
Restricted stock withheld for employee tax remittance (in shares)		(1)
Restricted stock withheld for employee tax remittance	(61)	$ (61)
Unrealized gain (loss) on investments	24		24
Ending balance (in shares) at Jun. 30, 2021		46,579
Ending balance at Jun. 30, 2021	151,092	$ 534,005	(23)	(382,890)
Increase (Decrease) in Shareholders' Equity
Net loss	(4,931)			(4,931)
Compensation expense related to stock options and restricted stock units granted, net of forfeitures	8,596	$ 8,596
Stock option exercises (in shares)		176
Stock option exercises	1,676	$ 1,676
Shares issued under the Employee Stock Purchase Plan (in shares)		9
Shares issued under the Employee Stock Purchase Plan	404	$ 404
Issuance of stock upon restricted stock unit vesting (in shares)		4
Issuance of stock upon restricted stock unit vesting	0
Restricted stock withheld for employee tax remittance (in shares)		(1)
Restricted stock withheld for employee tax remittance	(57)	$ (57)
Unrealized gain (loss) on investments	0
Ending balance (in shares) at Sep. 30, 2021		46,767
Ending balance at Sep. 30, 2021	$ 156,780	$ 544,624	$ (23)	$ (387,821)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net income (loss)	$ (12,006)	$ (9,356)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization expense	2,185	1,649
Stock-based compensation expense	26,481	10,819
Amortization of premiums and discounts on marketable securities	737	24
Non-cash lease cost	3,420	3,312
Other	17	89
Changes in operating assets and liabilities:
Inventory	(3,703)	(3,264)
Accounts receivable	5,594	5,994
Other current assets	(793)	(633)
Accounts payable	(672)	(52)
Accrued expenses	(361)	747
Operating lease liabilities	(2,410)	(3,110)
Other non-current assets and liabilities, net	0	16
Net cash provided by operating activities	18,489	6,235
Investing activities:
Purchases of investments	(49,375)	(29,049)
Sales and maturities of investments	50,913	39,123
Expenditures for property and equipment	(6,924)	(1,556)
Net cash provided by (used for) investing activities	(5,386)	8,518
Financing activities:
Net proceeds from common stock issuance	9,701	2,182
Payments on employee's behalf for taxes related to vesting of restricted stock units	(1,619)	(163)
Other	(252)	(32)
Net cash provided by financing activities	7,830	1,987
Net increase in cash, cash equivalents, and restricted cash	20,933	16,740
Cash, cash equivalents, and restricted cash at beginning of period	33,831	26,978
Cash, cash equivalents, and restricted cash at end of period	$ 54,764	$ 43,718

Organization

Organization	9 Months Ended
	Sep. 30, 2021
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 ® (autologous cultured chondrocytes on porcine collagen membrane) and Epicel ® (cultured epidermal autografts). MACI 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 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 ® (concentrate of proteolytic enzymes enriched in bromelain), a registration-stage biological orphan product for the 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 The pandemic caused by the spread of a novel strain of coronavirus (COVID-19) began directly affecting the United States in March of 2020 and has continued since that point. The pandemic has created significant disruptions to the U.S. and global economy and has contributed, at times, to significant volatility in financial markets. The global impact of the outbreak has fluctuated since early 2020. At times, 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 infection rates in the U.S. have risen and fallen, as new virus variants have emerged, as vaccines have been distributed and administered, 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. Notwithstanding being an essential business, the Company’s business and operations at time have been adversely impacted by the effects of COVID-19. For example, as a result of periodic restrictions placed on the performance of elective surgical procedures, the Company experienced a significant increase in cancellations of scheduled MACI procedures as well as a slowdown in new MACI orders during March and April of 2020. The widespread suspension of surgical procedures impacted the Company’s business and operations during the first and second quarters of 2020. The level and degree of restriction on elective surgeries, on the ability of patients to seek treatment and on U.S. business operations generally fluctuated throughout 2020 as COVID-19 infection rates rose and fell during the summer months and into the autumn. By the first quarter of 2021, the pandemic’s effects on the Company’s MACI business had largely dissipated. During the summer of 2021, however, the pandemic’s direct and ancillary effects again began to cause some disruption to the Company’s MACI business. For example, following the cessation of COVID-19-related travel restrictions in many parts of the United States and the availability of vaccinations in May and June 2021 some MACI patients postponed or delayed treatment – opting instead to take vacation and/or travel. Further, a surge of new COVID-19 cases during the summer of 2021 caused by the spread of the “Delta” variant again caused disruptions to health care networks, the scheduling of elective surgeries and overall patient behavior. These effects were compounded by staffing shortages at many healthcare facilities across the United States during the same period. Consequently, and notwithstanding the widespread distribution of vaccines in the United States, these factors contributed to a slowdown of MACI procedures during the third quarter of 2021. Although hospitals are now better prepared for subsequent surges 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 were to continue to rise, or if new or existing COVID-19 variants render current vaccine treatments ineffective. 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. At the outset of the pandemic, the Company put in place a comprehensive workplace protection plan, which instituted protective measures in response to COVID-19. The Company’s workplace protection plan has closely followed guidance issued by the Centers for Disease Control and Prevention (CDC) and has complied with applicable federal and state law. Because vaccines designed to protect against COVID-19 have become readily available and the rates of COVID-19 infections, hospitalizations and deaths in the majority of the U.S. have generally declined since their height at the beginning of 2021, the CDC and the Occupational Safety and Health Administration (OSHA) have altered their guidance for Americans, and emergency orders and mandatory workplace protocols in Michigan and Massachusetts have either been rescinded or greatly reduced – to include the lifting of all capacity limitations on businesses in both states. Accordingly, Vericel has begun a return to more normal workplace operations, but will continue to modify its workplace protection plan, and will reinstitute protective measures for its workforce as necessary. The Company continues to review its policies and procedures regularly, including the Company’s workplace protection plan, as the pandemic evolves and may take additional actions to the extent required. At-the-Market Offering On August 27, 2021, the Company entered into a Sales Agreement with SVB Leerink LLC, as sales agent (SVB Leerink), pursuant to which it may offer and sell up to $200.0 million of shares of the Company’s common stock, no par value per share (ATM Shares). The ATM Shares to be offered and sold under the Sales Agreement will be issued and sold pursuant to an automatically effective shelf registration statement on Form S-3ASR (File No. 333-259119) filed by the Company on August 27, 2021, which expires three years from the filing date. The Company also filed a prospectus supplement relating to the offering and sale of the ATM Shares on August 27, 2021. The Company is not obligated to make any sales of ATM Shares, and SVB Leerink is not required to sell any specific number or dollar amount of the ATM Shares under the Sales Agreement. The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process stock financings as deferred offering costs until such financings are consummated. As of September 30, 2021, the Company has sold no shares pursuant to the Sales Agreement. Going Concern The accompanying Condensed 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 the satisfaction of liabilities and commitments in the normal course of business. As of September 30, 2021, the Company had an accumulated deficit of $387.8 million, and had a net loss of $4.9 million and $12.0 million, respectively, during the three and nine months ended September 30, 2021. The Company had cash and cash equivalents of $54.6 million and investments of $64.0 million as of September 30, 2021. The Company expects that cash from the sales of its 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 these Condensed Consolidated Financial Statements. 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.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying Condensed Consolidated Financial Statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 are unaudited and have been prepared in accordance with the rules and regulations of the U.S. Securities and Exchange Commission (SEC). The preparation of Condensed Consolidated Financial Statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates, judgments, and assumptions that may affect the reported amounts of assets, liabilities, equity, revenue and expenses. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been omitted pursuant to such rules and regulations. The financial statements reflect, in the opinion of management, all adjustments (consisting only of normal, recurring adjustments) necessary to state fairly the financial position and results of operations as of and for the periods indicated. The Company bases its estimates on historical experience and on various other assumptions that it believes are reasonable, the results of which form the basis for making judgments about the carrying values of assets, liabilities and equity and the amount of revenue and expenses. The full extent to which the COVID-19 pandemic will continue to directly or indirectly impact its business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to continue to contain or treat COVID-19, as well as the economic impact on its customers. The Company has made estimates of the impact of COVID-19 within these financial statements and there may be changes to those estimates in future periods. Actual results may differ from these estimates. As of September 30, 2021, the Company has not recorded impairments to investments, inventory, other current assets or long-lived assets as a result of the COVID-19 pandemic. These Condensed Consolidated Financial Statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on February 24, 2021 (Annual Report). Consolidated Statement of Cash Flows The following table presents certain supplementary cash flows information for the nine months ended September 30, 2021 and 2020: Nine Months Ended September 30, (In thousands) 2021 2020 Supplementary Cash Flows information: Non-cash information: Right-of-use asset and lease liability recognized $ 45 $ 3,140 Additions to property and equipment included in accounts payable 85 340 Restricted stock held for employee tax remittance included in accounts payable (57) — Cash information: Interest paid $ 3 $ 5 Nine Months Ended September 30, (In thousands) 2021 2020 Reconciliation of cash, cash equivalents, and restricted cash reported in the statement of financial position: Cash and cash equivalents $ 54,553 $ 43,507 Restricted cash 211 211 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 54,764 $ 43,718

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements 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 became effective for the Company on January 1, 2021 and had no material impact on its Condensed Consolidated Financial Statements .

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Risks and Uncertainties [Abstract]
Revenue	Revenue Revenue Recognition and Net Product Sales 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 . MACI Biopsy Kits MACI biopsy kits are sold directly to hospitals and ambulatory surgical centers 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 engages 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 patients treated at military treatment facilities. 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 revenue 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. The total allowance for uncollectible consideration as of September 30, 2021 and December 31, 2020 was $7.2 million and $5.3 million, 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 increase or decrease in the revenue recognized as of the nine months ended September 30, 2021. 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 for the three and nine months ended September 30, 2021 resulted in an increase to revenue of $0.2 million and a decrease to revenue of $0.1 million, respectively, and an increase to revenue of approximately $0.01 million and $0.7 million, respectively, for the same periods in 2020. The changes in estimates recorded during the three and nine months ended September 30, 2021 and September 30, 2020, were primarily due to completion of the billing claims process for implants that occurred in 2020 or prior. Upon completion of the billing claims process, the Company concluded that it was probable that a significant reversal in the amount of revenue recognized would not occur. Additionally, potential credit risk exposure has been evaluated for the Company’s accounts receivable in accordance with ASC 326, Financial Instruments - Credit Losses. The loss percentage is calculated by pooling account receivables containing similar risk characteristics and applying collectability forecasts which are derived from current and historical economic and financial information. The loss percentage calculated was applied to accounts receivables as of September 30, 2021 and December 31, 2020. The allowance related to the potential impacts of COVID-19 on accounts receivable from third-party insurers, government payers, hospitals and patients as of December 31, 2020 included approximately $0.1 million, and no additional allowance was recorded during the nine months ended September 30, 2021. Epicel The Company sells Epicel directly to hospitals and burn centers 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 revenue 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 in May 2019, 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 U.S. Biomedical Advanced Research and Development Authority (BARDA) committed to procure NexoBrid directly from MediWound, under an emergency use authorization. As a result, during 2020, BARDA accepted the first shipments of NexoBrid, per the agreement between BARDA and MediWound. 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. As of September 30, 2021, the Company did not take title to the product or hold a direct contract or distribution agreement with BARDA. Revenue by Product and Customer The following table and description below shows the products from which the Company generated its revenue: Three Months Ended September 30, Nine Months Ended September 30, Revenue by product (in thousands) 2021 2020 2021 2020 MACI implants and kits Implants based on contracted rates sold through a specialty pharmacy (a) $ 15,149 $ 14,897 $ 46,547 $ 36,084 Implants subject to third party reimbursement sold through a specialty pharmacy (b) 3,463 3,529 11,357 10,299 Implants sold direct based on contracted rates (c) 3,895 4,602 12,876 9,528 Implants sold direct subject to third party reimbursement (d) 644 782 1,901 1,793 Biopsy kits - direct bill 577 539 1,647 1,348 Change in estimates related to prior periods (e) 153 8 (125) 695 Epicel Direct bill (hospital) 9,837 6,663 31,822 17,965 Total product revenue $ 33,718 $ 31,020 $ 106,025 $ 77,712 NexoBrid revenue (f) 788 1,238 2,568 1,238 Total net revenue $ 34,506 $ 32,258 $ 108,593 $ 78,950 (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 and AllCare whereby such specialty pharmacies do 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 the 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 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 The Company's total Epicel revenue concentration from a customer for the three and nine months ended September 30, 2021 was 9% and 11%, respectively, and there were no customers with a concentration greater than 10% for the same periods in 2020. For the Company's total MACI revenue, and MACI and Epicel accounts receivable balances, there were no customers for the three and nine months ended September 30, 2021 or the comparable periods in 2020, with a concentration greater than 10%.

Selected Balance Sheet Componen

Selected Balance Sheet Components	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Selected Balance Sheet Components	Selected Balance Sheet Components Inventory Inventory as of September 30, 2021 and December 31, 2020: (In thousands) September 30, 2021 December 31, 2020 Raw materials $ 12,014 $ 8,775 Work-in-process 976 537 Finished goods 68 44 Inventory $ 13,059 $ 9,356 Property and Equipment Property and Equipment, net as of September 30, 2021 and December 31, 2020: (In thousands) September 30, 2021 December 31, 2020 Machinery and equipment $ 4,365 $ 3,672 Furniture, fixtures and office equipment 1,551 809 Computer equipment and software 7,669 6,846 Leasehold improvements 10,277 5,560 Construction in process 1,416 2,021 Financing right-of-use lease 83 111 Total property and equipment, gross 25,361 19,019 Less accumulated depreciation (13,542) (11,386) Property and equipment, net $ 11,819 $ 7,633 Depreciation expense for the three and nine months ended September 30, 2021 was $0.7 million and $2.2 million, respectively, and $0.6 million and $1.6 million, respectively, for the same periods in 2020. Accrued Expenses Accrued Expenses as of September 30, 2021 and December 31, 2020 are as follows: (In thousands) September 30, 2021 December 31, 2020 Bonus related compensation $ 4,553 $ 5,721 Employee related accruals 2,975 3,482 Other accrued expenses 3,404 2,090 Accrued expenses $ 10,932 $ 11,293

Leases

Leases	9 Months Ended
	Sep. 30, 2021
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 facilities include 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. For both the three and nine months ended September 30, 2021 and 2020, lease expense of less than $0.1 million was recorded for each of short-term leases and financing leases. During the nine months ended September 30, 2021, the Company recorded $0.4 million of leasehold improvements funded by tenant improvement allowances available under the lease agreements. The contribution toward the cost of tenant improvements is recorded as a reduction of the operating lease assets. For the three and nine months ended September 30, 2021 , the Company recognized $1.8 million and $5.5 million, respectively, of operating lease expense and $1.6 million and $4.5 million, respectively for the same periods in 2020. 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 September 30, 2021 and December 31, 2020 are as follows: (In thousands) Classification September 30, 2021 December 31, 2020 Assets Operating Right-of-use assets $ 46,713 $ 50,105 Finance Property and equipment, net 83 111 Total leased assets $ 46,796 $ 50,216 Liabilities Current Operating Current portion of operating lease liabilities $ 2,280 $ 4,394 Finance Other liabilities 41 41 $ 2,321 $ 4,435 Non-current Operating Operating lease liabilities $ 48,493 $ 48,789 Finance Other long-term liabilities 42 76 Total leased liabilities $ 48,535 $ 48,865
Leases	Leases The Company leases facilities in Ann Arbor, Michigan and Cambridge, Massachusetts. The Ann Arbor facility includes office space, and the Cambridge facilities include 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. For both the three and nine months ended September 30, 2021 and 2020, lease expense of less than $0.1 million was recorded for each of short-term leases and financing leases. During the nine months ended September 30, 2021, the Company recorded $0.4 million of leasehold improvements funded by tenant improvement allowances available under the lease agreements. The contribution toward the cost of tenant improvements is recorded as a reduction of the operating lease assets. For the three and nine months ended September 30, 2021 , the Company recognized $1.8 million and $5.5 million, respectively, of operating lease expense and $1.6 million and $4.5 million, respectively for the same periods in 2020. 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 September 30, 2021 and December 31, 2020 are as follows: (In thousands) Classification September 30, 2021 December 31, 2020 Assets Operating Right-of-use assets $ 46,713 $ 50,105 Finance Property and equipment, net 83 111 Total leased assets $ 46,796 $ 50,216 Liabilities Current Operating Current portion of operating lease liabilities $ 2,280 $ 4,394 Finance Other liabilities 41 41 $ 2,321 $ 4,435 Non-current Operating Operating lease liabilities $ 48,493 $ 48,789 Finance Other long-term liabilities 42 76 Total leased liabilities $ 48,535 $ 48,865

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
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 non-qualified 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 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 Company's 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 of the 2019 Plan. 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 September 30, 2021, there were 2,730,746 shares available for future grant under the 2019 Plan. Employee Stock Purchase Plan Employees are able to purchase stock under the Vericel Corporation Employee Stock Purchase Plan (ESPP). The ESPP allows for the issuance of an aggregate of 1,000,000 shares of common stock of which 736,375 shares have been issued since the inception of the plan 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 options at the grant date, which corresponds to the first day of each purchase period and is amortized over the purchase period. In October 2021, employees purchased 7,102 shares resulting in proceeds from the sale of common stock of $0.3 million under the ESPP for the third quarter of 2021. Service-Based Stock Options During the three and nine months ended September 30, 2021, the Company granted service-based options to purchase common stock of 189,882 and 1,663,954, respectively, and 28,000 and 1,324,890, respectively, for the same periods in 2020. The exercise price of the options is the fair market value per share of common stock on the grant date, and the options generally vest over four years (other than non-employee director options which may vest over one Restricted Stock Units During the three and nine months ended September 30, 2021, the Company granted 22,310 and 263,364 service-based restricted stock units, respectively, and 0 and 196,836, respectively, for the same periods in 2020. 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 awards which may vest over one During the three and nine months ended September 30, 2021, 2,826 and 62,259 shares, respectively, of common stock were issued upon the vesting of restricted stock units. These amounts are net of 1,174 and 30,588 shares, respectively, that were withheld for payment of taxes on the behalf of employees. During the nine months ended September 30, 2020, 32,840 shares of common stock were issued upon the vesting of restricted stock units. This amount is net of 13,872 shares withheld for payment of taxes, as no shares are withheld at vesting for shares awarded to the members of the Company's Board of Directors. For the three and nine months ended September 30, 2021, the total fair value of restricted stock awards vested was $0.2 million and $5.1 million, respectively, and $0.0 million and $0.6 million, respectively, for the same periods in 2020. The total fair value of restricted stock units withheld for payment of taxes during the three and nine months ended September 30, 2021, was $0.1 million and $1.6 million, respectively. During the nine months ended September 30, 2020, the total fair value of restricted stock units withheld for payment of taxes was $0.2 million. No restricted stock units vested during the three months ended September 30, 2020. 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 product sales, research and development expenses and selling, general and administrative expenses is summarized in the following table: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2021 2020 2021 2020 Cost of product sales $ 1,114 $ 481 $ 3,313 $ 1,541 Research and development 1,126 458 3,222 1,455 Selling, general and administrative 6,356 1,736 19,946 7,823 Total non-cash stock-based compensation expense $ 8,596 $ 2,675 $ 26,481 $ 10,819

Investments

Investments	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Investments	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 accompanying Condensed Consolidated 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 September 30, 2021 and December 31, 2020: September 30, 2021 Gross Unrealized Estimated Fair Value (In thousands) Amortized Cost Gains Losses Credit Losses Commercial paper $ 13,243 $ — $ (1) $ — $ 13,242 Corporate notes 48,178 — (22) — 48,156 U.S. government securities 1,500 — — — 1,500 U.S. government agency bonds 1,075 — — — 1,075 $ 63,996 $ — $ (23) $ — $ 63,973 Classified as: Short-term investments $ 43,738 Long-term investments 20,235 $ 63,973 December 31, 2020 Gross Unrealized Estimated Fair Value (In thousands) Amortized Cost Gains Losses Credit Losses 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 $ 66,272 $ 20 $ — $ (6) $ 66,286 Classified as: Short-term investments $ 42,187 Long-term investments 24,099 $ 66,286 Investments classified as short-term have maturities of less than one year. Investments classified as long-term are those which: (i) have a maturity of greater than one year, and (ii) the Company does 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 September 30, 2021 and December 31, 2020 , 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 Condensed Consolidated Balance Sheets and Statements of Shareholders’ Equity and a component of total comprehensive income (loss) in the Condensed Consolidated Statements of Comprehensive 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 Condensed Consolidated Balance Sheet with a corresponding adjustment to earnings, and non-credit-related impairment is recognized in other comprehensive income (loss), net of taxes. There were no material realized losses on marketable securities during the three and nine months ended September 30, 2021. There have been no impairments of the Company’s assets measured and carried at fair value during the three and nine months ended September 30, 2021 or September 30, 2020, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
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, 2020 to September 30, 2021. 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: September 30, 2021 December 31, 2020 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 $ 6,146 $ 6,146 $ — $ — $ 3,698 $ 3,698 $ — $ — Commercial paper 13,242 — 13,242 — 8,994 — 8,994 — Corporate notes 48,156 — 48,156 — 35,911 — 35,911 — U.S. government securities 1,500 — 1,500 — 12,842 — 12,842 — U.S. government agency bonds 1,075 — 1,075 — 5,001 — 5,001 — U.S. asset-backed securities — — — — 3,538 — 3,538 — $ 70,119 $ 6,146 $ 63,973 $ — $ 69,984 $ 3,698 $ 66,286 $ —

Net Income (Loss) Per Common Sh

Net Income (Loss) Per Common Share	9 Months Ended
	Sep. 30, 2021
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: Three Months Ended September 30, Nine Months Ended September 30, (Amounts in thousands, except per share amounts) 2021 2020 2021 2020 Numerator: Net income (loss) $ (4,931) $ 3,618 $ (12,006) $ (9,356) Denominator: Weighted-average common shares outstanding (Basic) 46,669 45,272 46,355 45,112 Weighted-average common shares outstanding (Diluted) 46,669 47,314 46,355 45,112 Net income (loss) per common share (Basic and Diluted) $ (0.11) $ 0.08 $ (0.26) $ (0.21) Anti-dilutive shares excluded from the calculation of diluted earnings per share (a) : Stock options 5,852 2,390 5,852 5,692 Restricted stock units 412 — 412 273 (a) Common equivalent shares are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.

NexoBrid License and Supply Agr

NexoBrid License and Supply Agreements	9 Months Ended
	Sep. 30, 2021
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, in patients with deep partial and full-thickness thermal burns. On September 16, 2020, the Company announced acceptance of MediWound's submission of a biologics license application (BLA) for review by the U.S. Food and Drug Administration (FDA) to seek marketing approval for NexoBrid in the United States for the treatment of severe burns, and the FDA's assignment of a Prescription Drug User Fee Act (PDUFA) target date for the product of June 29, 2021. Subsequently, on June 29, 2021, the Company announced that MediWound received a complete response letter (CRL) from the FDA regarding the BLA, through which the FDA communicated to MediWound that it had completed its review of the BLA, as amended, and had determined that it cannot approve the BLA in its present form. The Company continues to work with MediWound, BARDA and the FDA to address the issues identified in the CRL, to prepare and submit a BLA resubmission to the FDA and to seek the potential approval of NexoBrid. Pursuant to the terms of the license agreement, if the BLA is approved, MediWound will transfer the BLA to the Company and the Company will market NexoBrid in the U.S. Both MediWound and the Company, 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, subsequent to approval. 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 September 30, 2021, the milestone payments were 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, following approval. 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	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies 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. In addition, the Company also pays for usage of an offsite warehouse space. In February 2021, the terms of the warehouse operating agreement were extended through March 31, 2027. The Company records rent expense related to this agreement on a straight-line basis over the remaining term. Future minimum payments related to the Company's contractual obligations are as follows: Payments Due by Period Contractual Obligations (in thousands) Total October 1, 2021 - December 31, 2021 2022 2023 2024 2025 More than 5 Years Purchase commitments $ 8,782 $ 3,011 $ 5,771 $ — $ — $ — $ — Warehouse operating agreement 4,930 263 1,046 1,046 792 792 991 Total $ 13,712 $ 3,274 $ 6,817 $ 1,046 $ 792 $ 792 $ 991

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements 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 became effective for the Company on January 1, 2021 and had no material impact on its Condensed Consolidated Financial Statements .

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Supplementary cash flows information	The following table presents certain supplementary cash flows information for the nine months ended September 30, 2021 and 2020: Nine Months Ended September 30, (In thousands) 2021 2020 Supplementary Cash Flows information: Non-cash information: Right-of-use asset and lease liability recognized $ 45 $ 3,140 Additions to property and equipment included in accounts payable 85 340 Restricted stock held for employee tax remittance included in accounts payable (57) — Cash information: Interest paid $ 3 $ 5 Nine Months Ended September 30, (In thousands) 2021 2020 Reconciliation of cash, cash equivalents, and restricted cash reported in the statement of financial position: Cash and cash equivalents $ 54,553 $ 43,507 Restricted cash 211 211 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 54,764 $ 43,718

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
Risks and Uncertainties [Abstract]
Disaggregation of Revenue	The following table and description below shows the products from which the Company generated its revenue: Three Months Ended September 30, Nine Months Ended September 30, Revenue by product (in thousands) 2021 2020 2021 2020 MACI implants and kits Implants based on contracted rates sold through a specialty pharmacy (a) $ 15,149 $ 14,897 $ 46,547 $ 36,084 Implants subject to third party reimbursement sold through a specialty pharmacy (b) 3,463 3,529 11,357 10,299 Implants sold direct based on contracted rates (c) 3,895 4,602 12,876 9,528 Implants sold direct subject to third party reimbursement (d) 644 782 1,901 1,793 Biopsy kits - direct bill 577 539 1,647 1,348 Change in estimates related to prior periods (e) 153 8 (125) 695 Epicel Direct bill (hospital) 9,837 6,663 31,822 17,965 Total product revenue $ 33,718 $ 31,020 $ 106,025 $ 77,712 NexoBrid revenue (f) 788 1,238 2,568 1,238 Total net revenue $ 34,506 $ 32,258 $ 108,593 $ 78,950 (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 and AllCare whereby such specialty pharmacies do 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 the 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 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)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of inventory	Inventory as of September 30, 2021 and December 31, 2020: (In thousands) September 30, 2021 December 31, 2020 Raw materials $ 12,014 $ 8,775 Work-in-process 976 537 Finished goods 68 44 Inventory $ 13,059 $ 9,356
Schedule of property and equipment, net	Property and Equipment, net as of September 30, 2021 and December 31, 2020: (In thousands) September 30, 2021 December 31, 2020 Machinery and equipment $ 4,365 $ 3,672 Furniture, fixtures and office equipment 1,551 809 Computer equipment and software 7,669 6,846 Leasehold improvements 10,277 5,560 Construction in process 1,416 2,021 Financing right-of-use lease 83 111 Total property and equipment, gross 25,361 19,019 Less accumulated depreciation (13,542) (11,386) Property and equipment, net $ 11,819 $ 7,633
Schedule of accrued expenses	Accrued Expenses as of September 30, 2021 and December 31, 2020 are as follows: (In thousands) September 30, 2021 December 31, 2020 Bonus related compensation $ 4,553 $ 5,721 Employee related accruals 2,975 3,482 Other accrued expenses 3,404 2,090 Accrued expenses $ 10,932 $ 11,293

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Assets And Liabilities	Total leased assets and liabilities classified on the balance sheet, as of September 30, 2021 and December 31, 2020 are as follows: (In thousands) Classification September 30, 2021 December 31, 2020 Assets Operating Right-of-use assets $ 46,713 $ 50,105 Finance Property and equipment, net 83 111 Total leased assets $ 46,796 $ 50,216 Liabilities Current Operating Current portion of operating lease liabilities $ 2,280 $ 4,394 Finance Other liabilities 41 41 $ 2,321 $ 4,435 Non-current Operating Operating lease liabilities $ 48,493 $ 48,789 Finance Other long-term liabilities 42 76 Total leased liabilities $ 48,535 $ 48,865

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
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 product sales, research and development expenses and selling, general and administrative expenses is summarized in the following table: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2021 2020 2021 2020 Cost of product sales $ 1,114 $ 481 $ 3,313 $ 1,541 Research and development 1,126 458 3,222 1,455 Selling, general and administrative 6,356 1,736 19,946 7,823 Total non-cash stock-based compensation expense $ 8,596 $ 2,675 $ 26,481 $ 10,819

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [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 September 30, 2021 and December 31, 2020: September 30, 2021 Gross Unrealized Estimated Fair Value (In thousands) Amortized Cost Gains Losses Credit Losses Commercial paper $ 13,243 $ — $ (1) $ — $ 13,242 Corporate notes 48,178 — (22) — 48,156 U.S. government securities 1,500 — — — 1,500 U.S. government agency bonds 1,075 — — — 1,075 $ 63,996 $ — $ (23) $ — $ 63,973 Classified as: Short-term investments $ 43,738 Long-term investments 20,235 $ 63,973 December 31, 2020 Gross Unrealized Estimated Fair Value (In thousands) Amortized Cost Gains Losses Credit Losses 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 $ 66,272 $ 20 $ — $ (6) $ 66,286 Classified as: Short-term investments $ 42,187 Long-term investments 24,099 $ 66,286

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
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: September 30, 2021 December 31, 2020 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 $ 6,146 $ 6,146 $ — $ — $ 3,698 $ 3,698 $ — $ — Commercial paper 13,242 — 13,242 — 8,994 — 8,994 — Corporate notes 48,156 — 48,156 — 35,911 — 35,911 — U.S. government securities 1,500 — 1,500 — 12,842 — 12,842 — U.S. government agency bonds 1,075 — 1,075 — 5,001 — 5,001 — U.S. asset-backed securities — — — — 3,538 — 3,538 — $ 70,119 $ 6,146 $ 63,973 $ — $ 69,984 $ 3,698 $ 66,286 $ —

Net Income (Loss) Per Common _2

Net Income (Loss) Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2021
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: Three Months Ended September 30, Nine Months Ended September 30, (Amounts in thousands, except per share amounts) 2021 2020 2021 2020 Numerator: Net income (loss) $ (4,931) $ 3,618 $ (12,006) $ (9,356) Denominator: Weighted-average common shares outstanding (Basic) 46,669 45,272 46,355 45,112 Weighted-average common shares outstanding (Diluted) 46,669 47,314 46,355 45,112 Net income (loss) per common share (Basic and Diluted) $ (0.11) $ 0.08 $ (0.26) $ (0.21) Anti-dilutive shares excluded from the calculation of diluted earnings per share (a) : Stock options 5,852 2,390 5,852 5,692 Restricted stock units 412 — 412 273 (a) Common equivalent shares are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Payments Related to Contractual Obligations	Future minimum payments related to the Company's contractual obligations are as follows: Payments Due by Period Contractual Obligations (in thousands) Total October 1, 2021 - December 31, 2021 2022 2023 2024 2025 More than 5 Years Purchase commitments $ 8,782 $ 3,011 $ 5,771 $ — $ — $ — $ — Warehouse operating agreement 4,930 263 1,046 1,046 792 792 991 Total $ 13,712 $ 3,274 $ 6,817 $ 1,046 $ 792 $ 792 $ 991

Organization - Narrative (Detai

Organization - Narrative (Details) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021USD ($)product	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2021USD ($)productsegment	Sep. 30, 2020USD ($)	Aug. 27, 2021USD ($)	Dec. 31, 2020USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of therapy products | product	2						2
Number of reportable segments | segment							1
Accumulated deficit	$ 387,821						$ 387,821			$ 375,815
Net loss	4,931	$ 3,786	$ 3,289	$ (3,618)	$ 8,269	$ 4,705	12,006	$ 9,356
Cash and cash equivalents	54,553			$ 43,507			54,553	$ 43,507		$ 33,620
Short term investments	$ 64,000						$ 64,000
At-The-Market
Subsidiary, Sale of Stock [Line Items]
Aggregate sale proceeds of up to									$ 200,000

Basis of Presentation - Supplem

Basis of Presentation - Supplementary cash flows information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Non-cash information:
Right-of-use asset and lease liability recognized	$ 45	$ 3,140
Additions to property and equipment included in accounts payable	85	340
Restricted stock held for employee tax remittance included in accounts payable	(57)	0
Interest paid	$ 3	$ 5

Basis of Presentation - Reconci

Basis of Presentation - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 54,553	$ 33,620	$ 43,507
Restricted cash	211		211
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 54,764	$ 33,831	$ 43,718	$ 26,978

Revenue (Details)

Revenue (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)pharmacy	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)pharmacy	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
CONCENTRATION
Number of specialty pharmacies | pharmacy	2		2
Allowance for doubtful accounts	$ 7,200,000		$ 7,200,000		$ 5,300,000
Change in estimate of uncollectible (percent)			0.50%
Change in revenue recognized due to 0.5% change in uncollectible percentage			$ 300,000
Increase (decrease) to revenues	33,718,000	$ 31,020,000	106,025,000	$ 77,712,000
COVID-19 potential impacts
CONCENTRATION
Allowance related to the potential impacts of COVID-19 (less than)					$ 100,000
Additional allowance recorded			0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
CONCENTRATION
Increase (decrease) to revenues	$ 153,000	$ 8,000	$ (125,000)	$ 695,000

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Product sales, net	$ 33,718	$ 31,020	$ 106,025	$ 77,712
Other revenue	788	1,238	2,568	1,238
Total revenue	34,506	32,258	108,593	78,950
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Product sales, net	153	8	(125)	695
MACI Implants and Kits, and Epicel
Disaggregation of Revenue [Line Items]
Product sales, net	33,718	31,020	106,025	77,712
NexoBid revenue
Disaggregation of Revenue [Line Items]
Other revenue	800	1,200	2,600
Through Intermediary | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	15,149	14,897	46,547	36,084
Through Intermediary | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	3,463	3,529	11,357	10,299
Time-and-materials contract | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	644	782	1,901	1,793
Provider or Facility | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	3,895	4,602	12,876	9,528
Provider or Facility | NexoBid revenue
Disaggregation of Revenue [Line Items]
Other revenue	788	1,238	2,568	1,238
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net	577	539	1,647	1,348
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net	$ 9,837	$ 6,663	$ 31,822	$ 17,965

Revenue - Schedules of concentr

Revenue - Schedules of concentration of risk (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021
Revenue Concentration | Customer concentration | Epicel
Product Information [Line Items]
Concentration risk (as a percent)	9.00%	11.00%

Selected Balance Sheet Compon_3

Selected Balance Sheet Components - Schedule of inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Inventory:
Raw materials	$ 12,014	$ 8,775
Work-in-process	976	537
Finished goods	68	44
Inventory	$ 13,059	$ 9,356

Selected Balance Sheet Compon_4

Selected Balance Sheet Components - Schedule of property and equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property and equipment, net:
Financing right-of-use lease	$ 83		$ 83		$ 111
Total property and equipment, gross	25,361		25,361		19,019
Less accumulated depreciation	(13,542)		(13,542)		(11,386)
Property and equipment, net	11,819		11,819		7,633
Depreciation expense	700	$ 600	2,200	$ 1,600
Machinery and equipment
Property and equipment, net:
Total property and equipment, gross	4,365		4,365		3,672
Furniture, fixtures and office equipment
Property and equipment, net:
Total property and equipment, gross	1,551		1,551		809
Computer equipment and software
Property and equipment, net:
Total property and equipment, gross	7,669		7,669		6,846
Leasehold improvements
Property and equipment, net:
Total property and equipment, gross	10,277		10,277		5,560
Construction in process
Property and equipment, net:
Total property and equipment, gross	$ 1,416		$ 1,416		$ 2,021

Selected Balance Sheet Compon_5

Selected Balance Sheet Components - Schedule of accrued expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accrued expenses
Bonus related compensation	$ 4,553	$ 5,721
Employee related accruals	2,975	3,482
Other accrued expenses	3,404	2,090
Accrued expenses	$ 10,932	$ 11,293

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	Oct. 21, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Short-term lease costs (less than)		$ 0.1	$ 0.1	$ 0.1	$ 0.1
Finance lease expense		0.1	0.1	0.1	0.1
Operating lease expense		$ 1.8	$ 1.6	5.5	$ 4.5
Leasehold improvements
Lessee, Lease, Description [Line Items]
Leasehold improvements recorded				$ 0.4
Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Tenant improvement allowance	$ 4.3
Minimum | Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Contractual lease payments	0.4
Maximum | Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Contractual lease payments	$ 0.6

Leases - Assets And Liabilities

Leases - Assets And Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Operating	$ 46,713	$ 50,105
Finance	83	111
Total leased assets	46,796	50,216
Current
Operating	2,280	4,394
Finance	41	41
Lease liability current	2,321	4,435
Non-current
Operating	48,493	48,789
Finance	42	76
Total leased liabilities	$ 48,535	$ 48,865
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended						9 Months Ended		81 Months Ended
	Oct. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Stock-Based Compensation
Shares issued under the Employee Stock Purchase Plan (in shares)		$ 404	$ 309	$ 249	$ 309	$ 257	$ 224
Fair value of restricted stock units withheld for payment of taxes		$ 57	$ 61	$ 1,501			$ 163
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)		2,730,746						2,730,746		2,730,746
Stock options
Stock-Based Compensation
Expiration period								10 years
Vesting period								4 years
Granted (in shares)		189,882			28,000			1,663,954	1,324,890
Weighted average grant-date fair value (in dollars per share)		$ 35.65			$ 10.81			$ 33.03	$ 8.70
Stock options | Nonemployee directors
Stock-Based Compensation
Expiration period								10 years
Stock options | Nonemployee directors | Minimum
Stock-Based Compensation
Vesting period								1 year
Stock options | Nonemployee directors | Maximum
Stock-Based Compensation
Vesting period								3 years
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)										736,375
Shares issued under the Employee Stock Purchase Plan (in shares)		$ 300
Employee stock | Subsequent event
Stock-Based Compensation
Shares purchased during period (in shares)	7,102
Restricted stock units
Stock-Based Compensation
Vesting period								4 years
Restricted stock units granted (shares)		22,310			0			263,364	196,836
Weighted-average grant date fair value (in usd per share)		$ 54.35						$ 52.19	$ 11.41
Grant-date fair value of restricted stock units granted		$ 1,200			$ 0			$ 13,700	$ 2,200
Shares vested in period (shares)		2,826						62,259	32,840
Restricted stock withheld for employee tax remittance (in shares)		1,174						30,588	13,872
Fair value of vested restricted stock awards		$ 200			$ 0			$ 5,100	$ 600
Fair value of restricted stock units withheld for payment of taxes		$ 100						$ 1,600	$ 200
Restricted stock units | Nonemployee directors | Minimum
Stock-Based Compensation
Vesting period								1 year
Restricted stock units | Nonemployee directors | Maximum
Stock-Based Compensation
Vesting period								3 years

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of non-cash stock-based compensation expense (Details) - Employee stock purchase plan and service-based stock options - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	$ 8,596	$ 2,675	$ 26,481	$ 10,819
Cost of product sales
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	1,114	481	3,313	1,541
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	1,126	458	3,222	1,455
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total non-cash stock-based compensation expense	$ 6,356	$ 1,736	$ 19,946	$ 7,823

Investments (Details)

Investments (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Marketable Securities [Line Items]
Amortized Cost	$ 63,996,000		$ 63,996,000		$ 66,272,000
Gains	0		0		20,000
Losses	(23,000)		(23,000)		0
Credit Losses	0		0		(6,000)
Estimated Fair Value	63,973,000		$ 63,973,000		$ 66,286,000
Remaining contractual maturity period			3 years		3 years
Impairments of assets	0	$ 0	$ 0	$ 0
Short-term investments
Marketable Securities [Line Items]
Estimated Fair Value	43,738,000		43,738,000		$ 42,187,000
Long-term investments
Marketable Securities [Line Items]
Estimated Fair Value	20,235,000		20,235,000		24,099,000
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	13,243,000		13,243,000		8,993,000
Gains	0		0		1,000
Losses	(1,000)		(1,000)		0
Credit Losses	0		0		0
Estimated Fair Value	13,242,000		13,242,000		8,994,000
Corporate notes
Marketable Securities [Line Items]
Amortized Cost	48,178,000		48,178,000		35,917,000
Gains	0		0		0
Losses	(22,000)		(22,000)		0
Credit Losses	0		0		(6,000)
Estimated Fair Value	48,156,000		48,156,000		35,911,000
U.S. government securities
Marketable Securities [Line Items]
Amortized Cost	1,500,000		1,500,000		12,828,000
Gains	0		0		14,000
Losses	0		0		0
Credit Losses	0		0		0
Estimated Fair Value	1,500,000		1,500,000		12,842,000
U.S. government agency bonds
Marketable Securities [Line Items]
Amortized Cost	1,075,000		1,075,000		5,000,000
Gains	0		0		1,000
Losses	0		0		0
Credit Losses	0		0		0
Estimated Fair Value	$ 1,075,000		$ 1,075,000		5,001,000
U.S. asset-backed securities
Marketable Securities [Line Items]
Amortized Cost					3,534,000
Gains					4,000
Losses					0
Credit Losses					0
Estimated Fair Value					$ 3,538,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	$ 63,973	$ 66,286
Recurring
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	70,119	69,984
Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	6,146	3,698
Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	63,973	66,286
Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Assets, fair value	0	0
Commercial paper | Recurring
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	13,242	8,994
Commercial paper | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Commercial paper | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	13,242	8,994
Commercial paper | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Corporate notes | Recurring
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	48,156	35,911
Corporate notes | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Corporate notes | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	48,156	35,911
Corporate notes | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. government securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,500	12,842
U.S. government securities | Recurring
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,500	12,842
U.S. government securities | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. government securities | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,500	12,842
U.S. government securities | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. government agency bonds
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,075	5,001
U.S. government agency bonds | Recurring
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,075	5,001
U.S. government agency bonds | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. government agency bonds | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	1,075	5,001
U.S. government agency bonds | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. asset-backed securities
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value		3,538
U.S. asset-backed securities | Recurring
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	3,538
U.S. asset-backed securities | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
U.S. asset-backed securities | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	3,538
U.S. asset-backed securities | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Debt securities, fair value	0	0
Money market funds | Recurring
Liabilities that are measured at fair value on a recurring basis
Money market funds	6,146	3,698
Money market funds | Recurring | Level 1
Liabilities that are measured at fair value on a recurring basis
Money market funds	6,146	3,698
Money market funds | Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Money market funds	0	0
Money market funds | Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Money market funds	$ 0	$ 0

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						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss)	$ (4,931)	$ (3,786)	$ (3,289)	$ 3,618	$ (8,269)	$ (4,705)	$ (12,006)	$ (9,356)
Weighted average common shares outstanding (Basic) (in shares)	46,669			45,272			46,355	45,112
Weighted average common shares outstanding (Diluted) (in shares)	46,669			47,314			46,355	45,112
Net income (loss) per common share (Basic) (in USD per share)	$ (0.11)			$ 0.08			$ (0.26)	$ (0.21)
Net income (loss) per common share (Diluted) (in USD per share)	$ (0.11)			$ 0.08			$ (0.26)	$ (0.21)
Stock options
Anti-dilutive shares excluded from the calculation of diluted earnings per share(a):
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	5,852			2,390			5,852	5,692
Restricted stock units
Anti-dilutive shares excluded from the calculation of diluted earnings per share(a):
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	412			0			412	273

NexoBrid License and Supply A_2

NexoBrid License and Supply Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related Party Transaction [Line Items]
Other revenue		$ 788	$ 1,238	$ 2,568	$ 1,238
NexoBrid
Related Party Transaction [Line Items]
Other revenue		$ 800	$ 1,200	$ 2,600
MediWound Ltd
Related Party Transaction [Line Items]
Consideration payment for license	$ 17,500
Payable	17,500
Contingent consideration	7,500
Max contingent consideration	125,000
Sales Initial milestone	$ 75,000
Term of supply agreement	5 years

Commitments and Contingencies -

Commitments and Contingencies - Future Minimum Payments (Details) $ in Thousands	Sep. 30, 2021USD ($)
Purchase commitments
Total	$ 8,782
October 1, 2021 - December 31, 2021	3,011
2022	5,771
2023	0
2024	0
2025	0
More than 5 Years	0
Operating Leases
Total	4,930
October 1, 2021 - December 31, 2021	263
2022	1,046
2023	1,046
2024	792
2025	792
More than 5 Years	991
Contractual Obligation, Fiscal Year Maturity [Abstract]
Total	13,712
October 1, 2021 - December 31, 2021	3,274
2022	6,817
2023	1,046
2024	792
2025	792
More than 5 Years	$ 991