we expect to select a lead product candidate in the first half of 2020 and provide a program update in the second half of 2020. gene therapy programs for the potential treatment of rare monogenic diseases rgx-501 : we are developing rgx-501 for the treatment of homozygous familial hypercholesterolemia ( hofh ) , a severe genetic disease characterized by premature and aggressive plaque buildup , life threatening coronary artery disease and aortic valve disease predominantly due to abnormalities in the function or expression of the receptor for low-density lipoprotein ( ldl-c ) . we have completed dosing of patients in the expanded second cohort of the phase i/ii clinical trial 76 for rgx-501 with corticosteroid prophylaxis , and we plan to assess ldl-c after all patients have completed steroid prophylaxis treatment . we expect to provide interim data in the first half of 2020. rgx-121 : we are developing rgx-121 for the treatment of the neurological symptoms of mucopolysaccharidosis type ii ( mps ii ) , a severe genetic lysosomal storage disease caused by deficiency of iduronate-2-sulfatase ( ids ) , an enzyme that is responsible for breakdown of cellular waste products . initial data from the first cohort demonstrated consistent and sustained reduction in heparan sulfate ( hs ) in the cerebral spinal fluid ( csf ) and available data support early signs of neurocognitive stability . we expect to provide additional data from the first cohort in mid-2020 , and we plan to complete enrollment in the second cohort in the first half of 2020 , with interim data available in the second half of 2020. rgx-111 : we are developing rgx-111 for the treatment of the neurological symptoms of mucopolysaccharidosis type i ( mps i ) , a severe genetic lysosomal storage disease caused by deficiency of α-l-iduronidase ( idua ) , an enzyme required for breakdown of cellular waste products . recruitment , screening and additional site activations are ongoing in the phase i clinical trial for rgx-111 . in october 2019 , rgx-111 was administered to a subject with mps i through an investigator-initiated study . rgx-181 : we are developing rgx-181 for the treatment of late-infantile neuronal ceroid lipofuscinosis type 2 ( cln2 ) disease , one of the most common forms of batten disease , caused by mutations in the tripeptidyl peptidase 1 ( tpp1 ) gene . we are conducting preclinical development of rgx-181 , including asessement of unmet clinical needs such as neurologic and ophthalmologic manifestations of the disease . we expect to provide a program update in mid-2020 and submit an ind for a first-in-human trial in the second half of 2020. gene therapy research program for the treatment of neuromuscular disorders : we expect to announce plans for the clinical development of a potential treatment for a neuromuscular disorder in the second half of 2020. in addition to our lead product candidates described above , we have also funded , and plan to continue to fund , preclinical research on potential product candidate programs that may become part of our internal product development pipeline . we have partnered with a number of leading academic institutions and will continue to seek partnerships with innovative institutions to develop novel nav gene therapy product candidates . overview of our nav technology platform in addition to our internal product development efforts , we also selectively license the nav technology platform to other leading biotechnology and pharmaceutical companies , which we refer to as nav technology licensees . as of december 31 , 2019 , our nav technology platform was being applied in one fda approved product ( zolgensma® ) , and the clinical development of 15 partnered product candidates , with over 20 partnered programs in total . licensing the nav technology platform allows us to maintain our internal product development focus on our core disease indications and therapeutic areas while still expanding the nav gene therapy pipeline , developing a greater breadth of treatments for patients , providing additional technological and potential clinical proof-of-concept for our nav technology platform , and creating potential additional revenue . financial overview revenues our revenues to date primarily consist of license and royalty revenue resulting from the licensing of our nav technology platform . we have not generated any revenues from commercial sales of our own products . if we fail to complete the development of our product candidates in a timely manner or fail to obtain their regulatory approval and adequate labeling , our ability to generate future revenues will be materially compromised . we license our nav technology platform to other biotechnology and pharmaceutical companies . the terms of the licenses vary , and licenses may be exclusive or non-exclusive and may be sublicensable by the licensee . licenses may grant intellectual property rights for purposes of internal and preclinical research and development only , or may include the rights , or options to obtain future rights , to commercialize drug therapies for specific diseases using the nav technology platform . license agreements generally have a term at least equal to the life of the underlying patents , but are terminable at the option of the licensee . consideration from licensees under our license agreements may include : ( i ) up-front and annual fees , ( ii ) option fees to acquire additional licenses , ( iii ) milestone payments based on the achievement of certain development and sales-based milestones by licensees , ( iv ) sublicense fees and ( v ) royalties on sales of licensed products . royalty revenue to date consists of royalties on net sales of zolgensma , which is marketed by avexis , inc. ( avexis ) , a wholly owned subsidiary of novartis ag ( novartis ) , for use in children less than two years old with spinal muscular atrophy ( sma ) . story_separator_special_tag at the inception of each license agreement that contains development milestone payments , we evaluate whether the milestones are considered probable of achievement and estimate the amount to be included in the transaction price using the most likely amount method . if it is probable that a significant revenue reversal will not occur in the future , milestone payments are included in the 81 transaction price and recognized as revenue upon the delivery of the license . milestone payments contingent on the achievement of development milestones that are not within our control or the control of the licensee , such as regulatory approvals , are not considered probable of being achieved and are excluded from the transaction price until the milestone is achieved . at each reporting date , we re-evaluate the probability of achievement of each outstanding development milestone and , if necessary , adjust the transaction price for any milestones for which the probability of achievement has changed due to current facts and circumstances . any such adjustments are recorded on a cumulative catch-up basis and recognized as revenue in the period of the adjustment . royalties on sales of licensed products , sales-based milestone payments and sublicense fees based on the receipt of certain fees by licensees from any sublicensees are excluded from the transaction price of each license and recognized as revenue in the period that the related sales or sublicenses occur , provided that the associated license has been delivered to the licensee . royalty revenue to date consists of royalties on net sales of zolgensma , which is a licensed product under our march 2014 license agreement , as amended , with avexis for the development and commercialization of treatments for sma . we recognize royalty revenue from net sales of zolgensma in the period in which the underlying products are sold by avexis , which in certain cases may require us to estimate royalty revenue for periods of net sales which have not yet been reported to us . sales-based milestone payments related to net sales of zolgensma are recognized as royalty revenue in the period in which the milestone is achieved . we receive payments from licensees based on the billing schedules established in each license agreement . amounts recognized as revenue which have not yet been received from licensees , including unbilled royalties , are recorded as accounts receivable when our rights to the consideration are conditional solely upon the passage of time . amounts recognized as revenue which have not yet been received from licensees are recorded as contract assets when our rights to the consideration are not unconditional . contract assets are recorded as other current assets on the consolidated balance sheets . if a licensee elects to terminate a license prior to the end of the license term , the licensed intellectual property is returned to us and any consideration recorded as accounts receivable or contract assets which is not contractually payable by the licensee is charged off as a reduction of license revenue in the period of the termination . amounts received by us prior to the delivery of underlying performance obligations are deferred and recognized as revenue upon the satisfaction of the performance obligations . deferred revenue which is not expected to be recognized within 12 months from the reporting date is recorded as non-current on the consolidated balance sheets . accrued research and development expenses we estimate our accrued research and development expenses as of each balance sheet date . this process involves reviewing contracts and purchase orders with service providers , identifying services that have been performed on our behalf and estimating the level of service performed , the expected remaining period of performance and the associated expenses incurred for the service when we have not yet been invoiced or otherwise notified of actual cost . depending on the timing of payments to the service providers and the estimated expenses incurred , we may record net prepaid or accrued research and development expenses relating to these costs . examples of estimated accrued research and development expenses include fees paid to : contract research organizations in connection with preclinical development and clinical studies ; contract manufacturing organizations and other vendors related to process development and manufacturing of materials for use in preclinical development and clinical studies ; and service providers for professional service fees such as consulting and other research and development related services . our understanding of the status and timing of services performed relative to the actual status and timing may vary and may result in us reporting changes in estimates in any particular period . to date , there have been no material differences from our estimates to the amount actually incurred . stock-based compensation our stock-based awards include stock options granted to employees and nonemployees , restricted stock units and shares issued under our employee stock purchase plan . our stock-based awards are subject to either service or performance-based vesting conditions . compensation expense related to awards to employees and nonemployees with service-based vesting conditions is recognized on a straight-line basis based on the estimated grant date fair value over the requisite service period of the award , which is generally the vesting term . compensation expense related to awards to employees and nonemployees with performance-based vesting conditions is recognized based on the 82 estimated grant date fair value over the requisite service period using the accelerated attribution method to the extent achievement of the performance condition is probable . we have elected to not estimate forfeitures of stock-based awards and to account for forfeitures as they occur . determination of the fair value of stock-based awards we estimate the fair value of our stock option awards using the black-scholes option-pricing model . the black-scholes option-pricing model requires the use of subjective assumptions , including ( i ) the fair value of the underlying common stock , ( ii ) the expected stock price volatility , ( iii ) the expected

cash flows replace_table_token_6_th cash flows from operating activities our net cash used in operating activities for the year ended december 31 , 2019 increased by $ 212.4 million from the year ended december 31 , 2018. the change was primarily attributable to $ 180.0 million in non-recurring license payments we received in 2018 related to the amendment of our march 2014 license agreement with avexis , as well as an increase in operating expenses in 2019. the increase in operating expenses during the period was primarily attributable to increased employee headcount and external research and development expenses as we continue the development and advancement of our lead product candidates and other research programs . for the year ended december 31 , 2019 , our net cash used in operating activities of $ 107.7 million consisted of a net loss of $ 94.7 million , $ 7.6 million in adjustments for non-cash items and changes in working capital of $ 5.3 million . adjustments for non-cash items primarily consisted of unrealized gains on our marketable equity securities of prevail of $ 31.8 million , net realized gains on marketable equity securities of $ 6.0 million , imputed interest earned from our license agreements of $ 3.0 million and net accretion of discounts on marketable debt securities of $ 1.2 million , and were partially offset by stock-based compensation expenses of $ 26.9 million and depreciation and amortization expense of $ 7.2 million . the changes in working capital were primarily attributable to an increase in accounts receivable of $ 8.6 million , an increase in other assets of $ 2.7 million and an increase in prepaid expenses of $ 1.0 million , and were partially offset by increases in accounts payable and accrued expenses and other current liabilities of $ 8.4 million .


 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.
     ```cash flows replace_table_token_6_th cash flows from operating activities our net cash used in operating activities for the year ended december 31 , 2019 increased by $ 212.4 million from the year ended december 31 , 2018. the change was primarily attributable to $ 180.0 million in non-recurring license payments we received in 2018 related to the amendment of our march 2014 license agreement with avexis , as well as an increase in operating expenses in 2019. the increase in operating expenses during the period was primarily attributable to increased employee headcount and external research and development expenses as we continue the development and advancement of our lead product candidates and other research programs . for the year ended december 31 , 2019 , our net cash used in operating activities of $ 107.7 million consisted of a net loss of $ 94.7 million , $ 7.6 million in adjustments for non-cash items and changes in working capital of $ 5.3 million . adjustments for non-cash items primarily consisted of unrealized gains on our marketable equity securities of prevail of $ 31.8 million , net realized gains on marketable equity securities of $ 6.0 million , imputed interest earned from our license agreements of $ 3.0 million and net accretion of discounts on marketable debt securities of $ 1.2 million , and were partially offset by stock-based compensation expenses of $ 26.9 million and depreciation and amortization expense of $ 7.2 million . the changes in working capital were primarily attributable to an increase in accounts receivable of $ 8.6 million , an increase in other assets of $ 2.7 million and an increase in prepaid expenses of $ 1.0 million , and were partially offset by increases in accounts payable and accrued expenses and other current liabilities of $ 8.4 million .
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 Suspicious Activity Report : we expect to select a lead product candidate in the first half of 2020 and provide a program update in the second half of 2020. gene therapy programs for the potential treatment of rare monogenic diseases rgx-501 : we are developing rgx-501 for the treatment of homozygous familial hypercholesterolemia ( hofh ) , a severe genetic disease characterized by premature and aggressive plaque buildup , life threatening coronary artery disease and aortic valve disease predominantly due to abnormalities in the function or expression of the receptor for low-density lipoprotein ( ldl-c ) . we have completed dosing of patients in the expanded second cohort of the phase i/ii clinical trial 76 for rgx-501 with corticosteroid prophylaxis , and we plan to assess ldl-c after all patients have completed steroid prophylaxis treatment . we expect to provide interim data in the first half of 2020. rgx-121 : we are developing rgx-121 for the treatment of the neurological symptoms of mucopolysaccharidosis type ii ( mps ii ) , a severe genetic lysosomal storage disease caused by deficiency of iduronate-2-sulfatase ( ids ) , an enzyme that is responsible for breakdown of cellular waste products . initial data from the first cohort demonstrated consistent and sustained reduction in heparan sulfate ( hs ) in the cerebral spinal fluid ( csf ) and available data support early signs of neurocognitive stability . we expect to provide additional data from the first cohort in mid-2020 , and we plan to complete enrollment in the second cohort in the first half of 2020 , with interim data available in the second half of 2020. rgx-111 : we are developing rgx-111 for the treatment of the neurological symptoms of mucopolysaccharidosis type i ( mps i ) , a severe genetic lysosomal storage disease caused by deficiency of α-l-iduronidase ( idua ) , an enzyme required for breakdown of cellular waste products . recruitment , screening and additional site activations are ongoing in the phase i clinical trial for rgx-111 . in october 2019 , rgx-111 was administered to a subject with mps i through an investigator-initiated study . rgx-181 : we are developing rgx-181 for the treatment of late-infantile neuronal ceroid lipofuscinosis type 2 ( cln2 ) disease , one of the most common forms of batten disease , caused by mutations in the tripeptidyl peptidase 1 ( tpp1 ) gene . we are conducting preclinical development of rgx-181 , including asessement of unmet clinical needs such as neurologic and ophthalmologic manifestations of the disease . we expect to provide a program update in mid-2020 and submit an ind for a first-in-human trial in the second half of 2020. gene therapy research program for the treatment of neuromuscular disorders : we expect to announce plans for the clinical development of a potential treatment for a neuromuscular disorder in the second half of 2020. in addition to our lead product candidates described above , we have also funded , and plan to continue to fund , preclinical research on potential product candidate programs that may become part of our internal product development pipeline . we have partnered with a number of leading academic institutions and will continue to seek partnerships with innovative institutions to develop novel nav gene therapy product candidates . overview of our nav technology platform in addition to our internal product development efforts , we also selectively license the nav technology platform to other leading biotechnology and pharmaceutical companies , which we refer to as nav technology licensees . as of december 31 , 2019 , our nav technology platform was being applied in one fda approved product ( zolgensma® ) , and the clinical development of 15 partnered product candidates , with over 20 partnered programs in total . licensing the nav technology platform allows us to maintain our internal product development focus on our core disease indications and therapeutic areas while still expanding the nav gene therapy pipeline , developing a greater breadth of treatments for patients , providing additional technological and potential clinical proof-of-concept for our nav technology platform , and creating potential additional revenue . financial overview revenues our revenues to date primarily consist of license and royalty revenue resulting from the licensing of our nav technology platform . we have not generated any revenues from commercial sales of our own products . if we fail to complete the development of our product candidates in a timely manner or fail to obtain their regulatory approval and adequate labeling , our ability to generate future revenues will be materially compromised . we license our nav technology platform to other biotechnology and pharmaceutical companies . the terms of the licenses vary , and licenses may be exclusive or non-exclusive and may be sublicensable by the licensee . licenses may grant intellectual property rights for purposes of internal and preclinical research and development only , or may include the rights , or options to obtain future rights , to commercialize drug therapies for specific diseases using the nav technology platform . license agreements generally have a term at least equal to the life of the underlying patents , but are terminable at the option of the licensee . consideration from licensees under our license agreements may include : ( i ) up-front and annual fees , ( ii ) option fees to acquire additional licenses , ( iii ) milestone payments based on the achievement of certain development and sales-based milestones by licensees , ( iv ) sublicense fees and ( v ) royalties on sales of licensed products . royalty revenue to date consists of royalties on net sales of zolgensma , which is marketed by avexis , inc. ( avexis ) , a wholly owned subsidiary of novartis ag ( novartis ) , for use in children less than two years old with spinal muscular atrophy ( sma ) . story_separator_special_tag at the inception of each license agreement that contains development milestone payments , we evaluate whether the milestones are considered probable of achievement and estimate the amount to be included in the transaction price using the most likely amount method . if it is probable that a significant revenue reversal will not occur in the future , milestone payments are included in the 81 transaction price and recognized as revenue upon the delivery of the license . milestone payments contingent on the achievement of development milestones that are not within our control or the control of the licensee , such as regulatory approvals , are not considered probable of being achieved and are excluded from the transaction price until the milestone is achieved . at each reporting date , we re-evaluate the probability of achievement of each outstanding development milestone and , if necessary , adjust the transaction price for any milestones for which the probability of achievement has changed due to current facts and circumstances . any such adjustments are recorded on a cumulative catch-up basis and recognized as revenue in the period of the adjustment . royalties on sales of licensed products , sales-based milestone payments and sublicense fees based on the receipt of certain fees by licensees from any sublicensees are excluded from the transaction price of each license and recognized as revenue in the period that the related sales or sublicenses occur , provided that the associated license has been delivered to the licensee . royalty revenue to date consists of royalties on net sales of zolgensma , which is a licensed product under our march 2014 license agreement , as amended , with avexis for the development and commercialization of treatments for sma . we recognize royalty revenue from net sales of zolgensma in the period in which the underlying products are sold by avexis , which in certain cases may require us to estimate royalty revenue for periods of net sales which have not yet been reported to us . sales-based milestone payments related to net sales of zolgensma are recognized as royalty revenue in the period in which the milestone is achieved . we receive payments from licensees based on the billing schedules established in each license agreement . amounts recognized as revenue which have not yet been received from licensees , including unbilled royalties , are recorded as accounts receivable when our rights to the consideration are conditional solely upon the passage of time . amounts recognized as revenue which have not yet been received from licensees are recorded as contract assets when our rights to the consideration are not unconditional . contract assets are recorded as other current assets on the consolidated balance sheets . if a licensee elects to terminate a license prior to the end of the license term , the licensed intellectual property is returned to us and any consideration recorded as accounts receivable or contract assets which is not contractually payable by the licensee is charged off as a reduction of license revenue in the period of the termination . amounts received by us prior to the delivery of underlying performance obligations are deferred and recognized as revenue upon the satisfaction of the performance obligations . deferred revenue which is not expected to be recognized within 12 months from the reporting date is recorded as non-current on the consolidated balance sheets . accrued research and development expenses we estimate our accrued research and development expenses as of each balance sheet date . this process involves reviewing contracts and purchase orders with service providers , identifying services that have been performed on our behalf and estimating the level of service performed , the expected remaining period of performance and the associated expenses incurred for the service when we have not yet been invoiced or otherwise notified of actual cost . depending on the timing of payments to the service providers and the estimated expenses incurred , we may record net prepaid or accrued research and development expenses relating to these costs . examples of estimated accrued research and development expenses include fees paid to : contract research organizations in connection with preclinical development and clinical studies ; contract manufacturing organizations and other vendors related to process development and manufacturing of materials for use in preclinical development and clinical studies ; and service providers for professional service fees such as consulting and other research and development related services . our understanding of the status and timing of services performed relative to the actual status and timing may vary and may result in us reporting changes in estimates in any particular period . to date , there have been no material differences from our estimates to the amount actually incurred . stock-based compensation our stock-based awards include stock options granted to employees and nonemployees , restricted stock units and shares issued under our employee stock purchase plan . our stock-based awards are subject to either service or performance-based vesting conditions . compensation expense related to awards to employees and nonemployees with service-based vesting conditions is recognized on a straight-line basis based on the estimated grant date fair value over the requisite service period of the award , which is generally the vesting term . compensation expense related to awards to employees and nonemployees with performance-based vesting conditions is recognized based on the 82 estimated grant date fair value over the requisite service period using the accelerated attribution method to the extent achievement of the performance condition is probable . we have elected to not estimate forfeitures of stock-based awards and to account for forfeitures as they occur . determination of the fair value of stock-based awards we estimate the fair value of our stock option awards using the black-scholes option-pricing model . the black-scholes option-pricing model requires the use of subjective assumptions , including ( i ) the fair value of the underlying common stock , ( ii ) the expected stock price volatility , ( iii ) the expected

