epicel ® ( cultured epidermal autografts ) is a permanent skin replacement hud for the treatment of adult and pediatric patients with deep-dermal or full-thickness burns comprising greater than or equal to 30 percent of tbsa . we also hold an exclusive license from mediwound ltd. for north american rights to nexobrid ® , ( concentrate of proteolytic enzymes enriched in bromelain ) , a registration-stage biological orphan product . on june 30 , 2020 , mediwound submitted to the fda a bla seeking the approval of nexobrid for eschar removal ( debridement ) in adults with deep partial-thickness and or full-thickness thermal burns . the fda subsequently accepted the bla for filing and has assigned a prescription drug user fee act ( pdufa ) target date of june 29 , 2021. covid-19 throughout 2020 , the pandemic caused by the spread of a novel strain of coronavirus ( covid-19 ) has created significant disruptions to the u.s. and global economy and has contributed to significant volatility in financial markets . the global impact of the outbreak is continually evolving and , as the virus spreads and infection rates surge in various locations , many state , local and national governments – including those in massachusetts and michigan , where our operations are located – have responded by issuing , extending and supplementing orders requiring quarantines , restrictions on travel , and the mandatory closure of certain non-essential businesses , among other actions . in the u.s. , the status and application of these orders have varied on a state-by-state basis since the early days of the pandemic . many of the restrictions have been periodically updated as infections rates in the u.s. have risen and fallen and as world health leaders learn more about the virus , its transmission pathway and who is most at risk . because vericel is deemed an essential business , we continue to be exempt from government orders , in their current form , requiring the closure of workplaces and the cessation of business operations . notwithstanding being an essential business , vericel 's business and operations have been adversely impacted by the effects of covid-19 . after the covid-19 pandemic began directly affecting the u.s. , in march 2020 , the american college of surgeons and united states surgeon general recommended that each hospital , health system , and surgeon minimize , postpone , or cancel electively scheduled surgeries . these recommendations were followed by numerous state level executive orders either 58 restricting or partially restricting elective surgeries . because maci is an elective surgical procedure , as a result of these restrictions , beginning in mid-march 2020 , we began to experience a significant increase in cancellations of scheduled maci procedures as well as a slowdown in new maci orders . the widespread suspension of elective procedures impacted our business and operations during the first and second quarters of 2020. these restrictions began to ease in may and by the end of september 2020 there were no state orders in place that directly impacted a surgeon 's or patient 's ability to move forward with a maci surgery . consequently , maci procedure and order volumes recovered throughout the third and fourth quarter of 2020 , and the majority of maci cases that had previously been canceled as a result of covid-19 factors were rescheduled . the covid-19 pandemic remains unpredictable , however , and in late september and october 2020 , the number of covid-19 infections began to increase markedly in various geographies and by late december 2020 the rolling seven-day average of new daily coronavirus cases in the united states reached the highest level at any point during the pandemic . as a result , the scheduling of maci pipeline cases during the last two weeks of december slowed compared to historical trends and there was an increase in case cancellations during that period . 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 , or that patients may choose to postpone or be unable to appear for a maci procedure if the number of covid-19 infections in the united states continues to rise . though epicel is used almost exclusively in an emergent setting by burn centers and surgeons throughout the country , epicel revenue and procedure volumes have been less affected by the pandemic . nevertheless , large burns and burn admissions can be affected by restrictions on human activity resulting from more severe government lockdown orders . epicel procedure volumes did experience a slow-down during the second quarter of 2020 , however , the reduction was less pronounced than that observed with maci . further reductions could be observed in the future , based on the degree of restrictions imposed . at the outset of the pandemic , vericel put in place a comprehensive workplace protection plan , which institutes protective measures in response to covid-19 . these measures include mandatory employee training on social distancing and hygiene protocols , conducting daily health screenings of all employees , vendors and visitors entering our facilities , canceling all international business travel , limiting domestic business travel to essential purpose travel only , requesting that employees limit non-essential personal travel , enhancing our facilities ' janitorial and sanitary procedures , making certain physical modifications and enhancements to our facilities to enable effective social distancing among employees , providing certain personal protective equipment to employees working in our offices , encouraging employees to work from home to the extent their job function enables them to do so , limiting third-party access to our facilities , encouraging the use of virtual employee meetings , modifying the manner and schedule of on-site production activities , and providing guidance to our field-based commercial teams concerning theircommunications and contact with customers and healthcare professionals . story_separator_special_tag revenue recognition and net product sales — revenue from sales to a customer ( distributor , hospital or other party ) is recognized in accordance with asc 606 , revenue recognition , which was adopted january 1 , 2018 . we recognize product revenue from sales to a customer ( distributor or hospital ) following the five step model in asc 606 : ( i ) identify contract ( s ) with a customer ; ( ii ) identify the performance obligations in the contract ; ( iii ) determine the transaction price ; ( iv ) allocate the transaction price to the performance obligations in the contract ; and ( v ) recognize revenues when ( or as ) we satisfy the 65 performance obligation . under this revenue standard , we recognize revenue when our customer obtains control of the promised goods , in an amount that reflects the consideration which we expect to receive in exchange for those goods . maci implants we have engaged a third-party services provider to provide the patient support program to manage patient cases and to ensure complete and accurate billing information is provided to the insurers and hospitals , to facilitate reimbursement . 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 . we recognize product revenues from sales of all maci implants upon delivery at which time the customer obtains control of the implant and the claim is billable . the total consideration which we expect 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 , there are typically no forms of variable consideration . when we sell maci the patient is responsible for payment ; however , we are 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 or a fee schedule . 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 our contractual arrangements . we estimate expected collections for these transactions using the portfolio approach . we record a reduction to revenue at the time of sale for the estimate of the amount of consideration that will not be collected . in addition , potential credit risk exposure has been evaluated for our accounts receivable in accordance with asc 326 , financial instruments - credit losses . we assess risk and determine a loss percentage by pooling account receivables based on similar risk characteristics . the loss percentage is calculated through the use of forecasts that are based on current and historical economic and financial information . changes in estimates of the transaction price are recorded through revenue in the period in which such change occurs . leases — we primarily enter into lease agreements for manufacturing and office space , warehouses space , vehicle and computer equipment . the leases have varying terms , some of which may include options to extend . we determine if an arrangement is a lease at contract inception . certain of our 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 such as an estimated incremental borrowing rate . our 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 to use ( rou ) assets and liabilities , on a discounted basis on the balance sheet . rou assets represent our right to control the use of an explicitly or implicitly identified fixed asset for a period of time and lease liabilities represent our obligation to make lease payments arising from the lease . control of an underlying asset is conveyed to us if we obtain the rights to direct the use of and to obtain substantially all of the economic benefits from using the underlying asset . lease payments included in the measurement of the lease liability are comprised of fixed payments . our leases contain non-lease components and activities that do not transfer a good or service to us which were not considered to be components of the contract and therefore were not included in the net rou assets or lease liabilities . the lease term for all of our leases include the non-cancellable period of the lease plus any additional periods covered by either an option to extend ( or not to terminate ) the lease that is reasonably certain to exercise , or an option to extend ( or not to terminate ) the lease controlled by the lessor . stock-based compensation — the accounting for stock-based compensation requires us to determine the fair value of common stock issued in the form of stock option awards and restricted stock units . the fair value of restricted stock units held by the employees is determined based on the fair value of our common stock on the date of the grant . we use the value of our common stock at the date of the grant in the calculation of the fair value of our share-based awards . the fair value of stock options held by our employees is determined using a black-scholes option valuation method , which is a valuation technique that is acceptable for share-based payment accounting . key assumptions in determining fair value include volatility , risk-free interest rate , dividend yield and expected term . the assumptions used

liquidity and capital resources since our acquisition in 2014 of maci , epicel and carticel , our primary focus has been to invest in our existing commercial business with the goal of growing revenue . we have raised significant funds in order to complete our product development programs and to market and commercialize our products including nexobrid . to date , we have financed our operations primarily through cash received through epicel and maci sales , debt and public and private sales of our equity securities . despite the effects of the covid-19 pandemic , we generated $ 17.6 million in operating cash flows during 2020 and we may continue to finance our commercial business operations through the sales of equity securities . cash flows the following table summarizes our sources and uses of cash for each of the periods presented : replace_table_token_10_th our cash and cash equivalents totaled $ 33.6 million , short-term investments totaled $ 42.2 million and long-term investments totaled $ 24.1 million as of december 31 , 2020. the $ 17.6 million of cash generated by operations was the result of a $ 2.9 million net income , additional noncash charges including $ 13.8 million in stock compensation expense , $ 4.4 million in operating lease amortization and $ 2.4 million in depreciation and amortization expense . working capital requirements increased due to a $ 2.3 million increase in accounts receivable and a $ 2.5 million increase in inventory , as a result of an increase in sales volume , slightly offset by $ 3.3 million in accrued expenses .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```liquidity and capital resources since our acquisition in 2014 of maci , epicel and carticel , our primary focus has been to invest in our existing commercial business with the goal of growing revenue . we have raised significant funds in order to complete our product development programs and to market and commercialize our products including nexobrid . to date , we have financed our operations primarily through cash received through epicel and maci sales , debt and public and private sales of our equity securities . despite the effects of the covid-19 pandemic , we generated $ 17.6 million in operating cash flows during 2020 and we may continue to finance our commercial business operations through the sales of equity securities . cash flows the following table summarizes our sources and uses of cash for each of the periods presented : replace_table_token_10_th our cash and cash equivalents totaled $ 33.6 million , short-term investments totaled $ 42.2 million and long-term investments totaled $ 24.1 million as of december 31 , 2020. the $ 17.6 million of cash generated by operations was the result of a $ 2.9 million net income , additional noncash charges including $ 13.8 million in stock compensation expense , $ 4.4 million in operating lease amortization and $ 2.4 million in depreciation and amortization expense . working capital requirements increased due to a $ 2.3 million increase in accounts receivable and a $ 2.5 million increase in inventory , as a result of an increase in sales volume , slightly offset by $ 3.3 million in accrued expenses .
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 Suspicious Activity Report : epicel ® ( cultured epidermal autografts ) is a permanent skin replacement hud for the treatment of adult and pediatric patients with deep-dermal or full-thickness burns comprising greater than or equal to 30 percent of tbsa . we also hold an exclusive license from mediwound ltd. for north american rights to nexobrid ® , ( concentrate of proteolytic enzymes enriched in bromelain ) , a registration-stage biological orphan product . on june 30 , 2020 , mediwound submitted to the fda a bla seeking the approval of nexobrid for eschar removal ( debridement ) in adults with deep partial-thickness and or full-thickness thermal burns . the fda subsequently accepted the bla for filing and has assigned a prescription drug user fee act ( pdufa ) target date of june 29 , 2021. covid-19 throughout 2020 , the pandemic caused by the spread of a novel strain of coronavirus ( covid-19 ) has created significant disruptions to the u.s. and global economy and has contributed to significant volatility in financial markets . the global impact of the outbreak is continually evolving and , as the virus spreads and infection rates surge in various locations , many state , local and national governments – including those in massachusetts and michigan , where our operations are located – have responded by issuing , extending and supplementing orders requiring quarantines , restrictions on travel , and the mandatory closure of certain non-essential businesses , among other actions . in the u.s. , the status and application of these orders have varied on a state-by-state basis since the early days of the pandemic . many of the restrictions have been periodically updated as infections rates in the u.s. have risen and fallen and as world health leaders learn more about the virus , its transmission pathway and who is most at risk . because vericel is deemed an essential business , we continue to be exempt from government orders , in their current form , requiring the closure of workplaces and the cessation of business operations . notwithstanding being an essential business , vericel 's business and operations have been adversely impacted by the effects of covid-19 . after the covid-19 pandemic began directly affecting the u.s. , in march 2020 , the american college of surgeons and united states surgeon general recommended that each hospital , health system , and surgeon minimize , postpone , or cancel electively scheduled surgeries . these recommendations were followed by numerous state level executive orders either 58 restricting or partially restricting elective surgeries . because maci is an elective surgical procedure , as a result of these restrictions , beginning in mid-march 2020 , we began to experience a significant increase in cancellations of scheduled maci procedures as well as a slowdown in new maci orders . the widespread suspension of elective procedures impacted our business and operations during the first and second quarters of 2020. these restrictions began to ease in may and by the end of september 2020 there were no state orders in place that directly impacted a surgeon 's or patient 's ability to move forward with a maci surgery . consequently , maci procedure and order volumes recovered throughout the third and fourth quarter of 2020 , and the majority of maci cases that had previously been canceled as a result of covid-19 factors were rescheduled . the covid-19 pandemic remains unpredictable , however , and in late september and october 2020 , the number of covid-19 infections began to increase markedly in various geographies and by late december 2020 the rolling seven-day average of new daily coronavirus cases in the united states reached the highest level at any point during the pandemic . as a result , the scheduling of maci pipeline cases during the last two weeks of december slowed compared to historical trends and there was an increase in case cancellations during that period . 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 , or that patients may choose to postpone or be unable to appear for a maci procedure if the number of covid-19 infections in the united states continues to rise . though epicel is used almost exclusively in an emergent setting by burn centers and surgeons throughout the country , epicel revenue and procedure volumes have been less affected by the pandemic . nevertheless , large burns and burn admissions can be affected by restrictions on human activity resulting from more severe government lockdown orders . epicel procedure volumes did experience a slow-down during the second quarter of 2020 , however , the reduction was less pronounced than that observed with maci . further reductions could be observed in the future , based on the degree of restrictions imposed . at the outset of the pandemic , vericel put in place a comprehensive workplace protection plan , which institutes protective measures in response to covid-19 . these measures include mandatory employee training on social distancing and hygiene protocols , conducting daily health screenings of all employees , vendors and visitors entering our facilities , canceling all international business travel , limiting domestic business travel to essential purpose travel only , requesting that employees limit non-essential personal travel , enhancing our facilities ' janitorial and sanitary procedures , making certain physical modifications and enhancements to our facilities to enable effective social distancing among employees , providing certain personal protective equipment to employees working in our offices , encouraging employees to work from home to the extent their job function enables them to do so , limiting third-party access to our facilities , encouraging the use of virtual employee meetings , modifying the manner and schedule of on-site production activities , and providing guidance to our field-based commercial teams concerning theircommunications and contact with customers and healthcare professionals . story_separator_special_tag revenue recognition and net product sales — revenue from sales to a customer ( distributor , hospital or other party ) is recognized in accordance with asc 606 , revenue recognition , which was adopted january 1 , 2018 . we recognize product revenue from sales to a customer ( distributor or hospital ) following the five step model in asc 606 : ( i ) identify contract ( s ) with a customer ; ( ii ) identify the performance obligations in the contract ; ( iii ) determine the transaction price ; ( iv ) allocate the transaction price to the performance obligations in the contract ; and ( v ) recognize revenues when ( or as ) we satisfy the 65 performance obligation . under this revenue standard , we recognize revenue when our customer obtains control of the promised goods , in an amount that reflects the consideration which we expect to receive in exchange for those goods . maci implants we have engaged a third-party services provider to provide the patient support program to manage patient cases and to ensure complete and accurate billing information is provided to the insurers and hospitals , to facilitate reimbursement . 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 . we recognize product revenues from sales of all maci implants upon delivery at which time the customer obtains control of the implant and the claim is billable . the total consideration which we expect 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 , there are typically no forms of variable consideration . when we sell maci the patient is responsible for payment ; however , we are 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 or a fee schedule . 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 our contractual arrangements . we estimate expected collections for these transactions using the portfolio approach . we record a reduction to revenue at the time of sale for the estimate of the amount of consideration that will not be collected . in addition , potential credit risk exposure has been evaluated for our accounts receivable in accordance with asc 326 , financial instruments - credit losses . we assess risk and determine a loss percentage by pooling account receivables based on similar risk characteristics . the loss percentage is calculated through the use of forecasts that are based on current and historical economic and financial information . changes in estimates of the transaction price are recorded through revenue in the period in which such change occurs . leases — we primarily enter into lease agreements for manufacturing and office space , warehouses space , vehicle and computer equipment . the leases have varying terms , some of which may include options to extend . we determine if an arrangement is a lease at contract inception . certain of our 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 such as an estimated incremental borrowing rate . our 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 to use ( rou ) assets and liabilities , on a discounted basis on the balance sheet . rou assets represent our right to control the use of an explicitly or implicitly identified fixed asset for a period of time and lease liabilities represent our obligation to make lease payments arising from the lease . control of an underlying asset is conveyed to us if we obtain the rights to direct the use of and to obtain substantially all of the economic benefits from using the underlying asset . lease payments included in the measurement of the lease liability are comprised of fixed payments . our leases contain non-lease components and activities that do not transfer a good or service to us which were not considered to be components of the contract and therefore were not included in the net rou assets or lease liabilities . the lease term for all of our leases include the non-cancellable period of the lease plus any additional periods covered by either an option to extend ( or not to terminate ) the lease that is reasonably certain to exercise , or an option to extend ( or not to terminate ) the lease controlled by the lessor . stock-based compensation — the accounting for stock-based compensation requires us to determine the fair value of common stock issued in the form of stock option awards and restricted stock units . the fair value of restricted stock units held by the employees is determined based on the fair value of our common stock on the date of the grant . we use the value of our common stock at the date of the grant in the calculation of the fair value of our share-based awards . the fair value of stock options held by our employees is determined using a black-scholes option valuation method , which is a valuation technique that is acceptable for share-based payment accounting . key assumptions in determining fair value include volatility , risk-free interest rate , dividend yield and expected term . the assumptions used

