given these uncertainties , we caution investors not to unduly rely on our forward-looking statements . we do not undertake any obligation to review or confirm analysts ' expectations or estimates or to release publicly any revisions to any forward-looking statements to reflect events or circumstances after the date of this report or to reflect the occurrence of unanticipated events , except as required by applicable law or regulation . business overview & recent developments we are principally engaged in the development , manufacture and marketing of pharmaceutical products for human use in connection with a variety of high-incidence and high-mortality diseases and medical conditions prevalent in the people 's republic of china ( the “ prc ” ) . all of our operations are conducted in the prc , where our manufacturing facilities are located . we manufacture pharmaceutical products in the form of dry powder injectables , liquid injectables , tablets , capsules , and cephalosporin oral solutions . the majority of our pharmaceutical products are sold on a prescription basis and all have been approved for at least one or more therapeutic indications by the national medical products administration ( the “ nmpa ” , formerly china food and drug administration , or cfda ) based upon demonstrated safety and efficacy . the 2019 statistical communique on the development of china 's health and health industry shows that by the end of 2019 , the total number of medical and health institutions in china reached 1,007,545 , which represented an increase of 1,345 hospitals and 10,751 primary health care institutions compared with the condition in the previous year . there are 8.807 million beds in the national health care institutions by the end of 2019. public and private hospitals accounted for 72.5 % and 27.5 % , respectively , for the beds in all hospitals . the number of beds in health facilities per 1,000 population increased from 6.03 in 2018 to 6.30 in 2019. drug consistency evaluation is a drug quality requirement in china 's 12th five-year plan for drug safety , that is , the state requires generic drugs to be consistent with the quality and efficacy of their corresponding original drugs . china 's consistency evaluation of generic drugs had continued to proceed in 2020. the supporting policies from central and provincial governments have been constantly issued , including polices regarding consistency evaluation for injectable products . we have always taken the task of facilitating the consistency evaluation as our top priority , and worked on them actively . however , due to the continuous dynamic changes of the detailed policies , future market , expected investment , and return of investment ( “ roi ” ) for each drug 's consistency evaluation , the whole industry , including us , has been making slow progress in terms of the consistency evaluation . 36 we have taken a more cautious and flexible attitude towards the initiating and progressing of an existing product 's consistency evaluation and to cope with the changing macro environment of drug sales in china . on the one hand , since `` 4 + 7 `` ( refers to 11 selected pilot cities , including 4 municipalities and 7 other cities ) trial centralized procurement ( “ cp ” ) activities initiated in 2018 , four rounds of cpcp activities had been carried out by march 2021 , which significantly reduced the price of the drugs that won the bids . on the other hand , the consistency evaluation has been adopted as one of the qualification standards for participating in the cp activities . as a result , we need to balance at least the two factors above before making decisions for any products . we have a product that passed biological equivalents experiments of consistency evaluation in march 2021. we plan to submit relevant documentation and data to nmpa in the near future . in addition , we continue to explore in the field of comprehensive healthcare . comprehensive healthcare is a general concept proposed according to the development of the times , social needs and changes in disease spectrum . according to the outline of `` healthy china 2030 `` issued by chinese government in october 2016 , the total size of china 's health service industry will reach more than rmb 8 trillion by 2020 and rmb 16 trillion by 2030. this industry focuses on people 's daily life , aging and disease , pays attention to all kinds of risk factors and misunderstandings affecting health , and calls for self-health management , and advocates the comprehensive care of the entire process of life . it covers all kinds of health-related information , products and services , as well as actions taken by various organizations to meet the health needs . we launched noni enzyme , a natural , healthy and nutrition-rich food supplement at the end of 2018 , and wash-free sanitizer and masks in 2020 to address the market needs caused by covid-19 in china . in addition , we also actively responded to the market demand for covid-19 related products , and completed a one-time covid-19 tester export transaction in 2020. we will continue to optimize our product structure and actively respond to the current health needs of human beings . market trends as a generic drug company we are presented with a huge domestic market . we believe that through further upgrades and consistency evaluations , we will be able to meet the european and american production standards , which enables us to export our products to overseas markets . in the future , cost management and control ability will gradually become an important factor in determining the competitiveness of generic pharmaceutical enterprises . story_separator_special_tag 38 cost of revenue for the year ended december 31 , 2020 , our cost of revenue was $ 9.0 million , or 82.0 % of total revenue , which represented a decrease of $ 0.4 million from $ 9.4 million , or 86.4 % of total revenue , in 2019. this was mainly due to the impact of the one-time covid-19 tester transaction and the government relief for employees ' social insurance in 2020. gross profit and gross margin gross profit for the year ended december 31 , 2020 was $ 2.0 million , compared to $ 1.5 million in 2019. our gross profit margin in 2020 was 18.0 % compared to 13.6 % in 2019. this increase in our gross profit margin was mainly due to the impact of the one-time covid-19 tester transaction and the government relief for employees ' social insurance in 2020. selling expenses our selling expenses for the year ended december 31 , 2020 were $ 2.2 million , a decrease of $ 0.2 million compared to $ 2.4 million for the year ended december 31 , 2019. selling expenses accounted for 20.4 % of the total revenue in 2020 compared to 21.5 % in 2019. this decrease was mainly due to emergency quarantine measures which reduced business travel and marketing activities due to the covid-19 pandemic . general and administrative expenses our general and administrative expenses for the year ended december 31 , 2020 were $ 1.8 million , as compared to $ 2.3 million in 2019. general and administrative expenses accounted for 16.8 % and 21.0 % of our total revenues in 2020 and 2019 , respectively . this decrease was mainly due to lower travel and office costs due to the impact of covid-19 , as well as offsets for administrative costs from government subsidies . research and development expenses our research and development expenses for the year ended december 31 , 2020 was $ 0.38 million , compared to $ 0.23 million in 2019. research and development expenses accounted for 3.5 % and 2.1 % of our total revenues in 2020 and 2019 , respectively . these expenditures were mainly spent on the consistency evaluation of our existing products . impairment loss there was no impairment loss for the year ended december 31 , 2020. however , we recognized $ 17.02 million impairment loss for the year ended december 31 , 2019 , among which , there was an impairment loss for the advances made to laboratories for the year december 31 , 2019 in the amount of $ 17,015,117. as a pharmaceutical company , we have been focusing on the development and maintenance of our intangible assets , mainly in the form of medical formulas . the consistency evaluations discussed under the “ business overview & recent developments ” section hereof is expected to have a significant impact on all generic products not only in our pipeline , but also throughout the existing chinese market . after evaluating the detailed rules under this policy , in addition to the potential roi and our recent cash flow position , our management made certain assessments regarding the impairment of our intangible assets , and identified four formulas that would likely to be unable to generate positive cash flow in the foreseeable future and therefore recognized impairment loss on them accordingly as of december 31 , 2019. the management determined to impair all advances at december 31 , 2019 , but may resume the development of these formulas in the future if sufficient funding and other favorable conditions arise . bad debt expenses our bad debt expenses for the year ended december 31 , 2020 was $ 115,186 , as compared to $ 3,153 in 2019. this increase was mainly due to the write-off of accounts receivable from some customers who ceased operations due to the covid-19 outbreak in 2020. in general , our normal customer credit or payment terms are 90 days . this has not changed in recent years . due to the peculiar environment affecting the chinese pharmaceutical market , deferred payments to pharmaceutical companies by state-owned hospitals and local medicine distributors are common . the amount of net accounts receivable that were past due ( or the amount of accounts receivable that were more than 180 days old ) was $ 0.06 million and $ 0.15 million as of december 31 , 2020 and 2019 , respectively . 39 the following table illustrates our accounts receivable aging distribution in terms of the percentage of the total accounts receivable as of december 31 , 2020 and 2019 : replace_table_token_3_th our bad debt allowance estimate practice is that we consider accounts receivable balances aged within 180 days current , except for any individual uncollectible account assessed by management . we account for the following respective percentage as bad debt allowance based on age of the accounts receivables : 10 % of accounts receivable that are between 180 days and 365 days old , 70 % of accounts receivable that are between 365 days and 720 days old , and 100 % of accounts receivable that are greater than 720 days old . we recognize bad debt expenses per actual write-offs as well as changes of allowance for doubtful accounts . to the extent that our current allowance for doubtful accounts is higher than that of the previous period , we recognize a bad debt expense for the difference during the current period , and when the current allowance is lower than that of the previous period , we recognize a bad debt credit for the difference . the allowance for doubtful account balances were $ 18.2 million and $ 17.6 million as of december 31 , 2020 and december 31 , 2019 , respectively . the changes in the allowances for doubtful accounts during the years ended december 31 , 2020 and 2019 were as follows : replace_table_token_4_th loss from operations our operating loss for the year ended december 31

liquidity and capital resources our principal source of liquidity is cash generated from operations and bank lines of credit . in addition to the aggregated advance of $ 724,963 from our ceo in 2019 , we received some temporary advances from and made several repayments to her in 2020. as of december 31 , 2020 , the aggregated advance from our ceo was $ 740,316 for use in operations . our cash and cash equivalents were $ 1.0 million , representing 4.5 % of our total assets , as of december 31 , 2020 , as compared to $ 1.1 million , representing 4.8 % of our total assets as of december 31 , 2019. all of the $ 1.0 million of cash and cash equivalents as of december 31 , 2020 are considered to be reinvested indefinitely in the company 's chinese subsidiary , helpson and is not expected to be available for payment of dividends or for other payments to its parent company or to its shareholders . in april 2020 , the company obtained a line of credit from postal savings bank of china for an aggregate amount of rmb 10,000,000 ( approximately $ 1.4 million ) , of which rmb 8,000,000 ( approximately $ 1.2 million ) have been advanced at december 31 , 2020. the loan bears interest at a rate of 4.25 % per annum . advances on the line of credit shall be repaid in installments semi-annually for two years from the date of the advance ; the first repayment of rmb 500,000 ( approximately $ 0.07 million ) was made on october 20 , 2020 , and the second repayment of rmb 300,000 ( approximately $ 0.06 million ) was made in january 2021. the company has an additional rmb 2,000,000 ( approximately $ 0.3 million ) available under the line , subject to a risk review and approval by the third party guarantee company . on june 30 , 2020 the company obtained a line of credit with bank of communications for an aggregate amount of rmb 8,500,000 ( approximately $ 1.3 million ) , all of which have been advanced . the loan bears interest at a rate of 4.05 % per annum .


 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 our principal source of liquidity is cash generated from operations and bank lines of credit . in addition to the aggregated advance of $ 724,963 from our ceo in 2019 , we received some temporary advances from and made several repayments to her in 2020. as of december 31 , 2020 , the aggregated advance from our ceo was $ 740,316 for use in operations . our cash and cash equivalents were $ 1.0 million , representing 4.5 % of our total assets , as of december 31 , 2020 , as compared to $ 1.1 million , representing 4.8 % of our total assets as of december 31 , 2019. all of the $ 1.0 million of cash and cash equivalents as of december 31 , 2020 are considered to be reinvested indefinitely in the company 's chinese subsidiary , helpson and is not expected to be available for payment of dividends or for other payments to its parent company or to its shareholders . in april 2020 , the company obtained a line of credit from postal savings bank of china for an aggregate amount of rmb 10,000,000 ( approximately $ 1.4 million ) , of which rmb 8,000,000 ( approximately $ 1.2 million ) have been advanced at december 31 , 2020. the loan bears interest at a rate of 4.25 % per annum . advances on the line of credit shall be repaid in installments semi-annually for two years from the date of the advance ; the first repayment of rmb 500,000 ( approximately $ 0.07 million ) was made on october 20 , 2020 , and the second repayment of rmb 300,000 ( approximately $ 0.06 million ) was made in january 2021. the company has an additional rmb 2,000,000 ( approximately $ 0.3 million ) available under the line , subject to a risk review and approval by the third party guarantee company . on june 30 , 2020 the company obtained a line of credit with bank of communications for an aggregate amount of rmb 8,500,000 ( approximately $ 1.3 million ) , all of which have been advanced . the loan bears interest at a rate of 4.05 % per annum .
```    
 Suspicious Activity Report : given these uncertainties , we caution investors not to unduly rely on our forward-looking statements . we do not undertake any obligation to review or confirm analysts ' expectations or estimates or to release publicly any revisions to any forward-looking statements to reflect events or circumstances after the date of this report or to reflect the occurrence of unanticipated events , except as required by applicable law or regulation . business overview & recent developments we are principally engaged in the development , manufacture and marketing of pharmaceutical products for human use in connection with a variety of high-incidence and high-mortality diseases and medical conditions prevalent in the people 's republic of china ( the “ prc ” ) . all of our operations are conducted in the prc , where our manufacturing facilities are located . we manufacture pharmaceutical products in the form of dry powder injectables , liquid injectables , tablets , capsules , and cephalosporin oral solutions . the majority of our pharmaceutical products are sold on a prescription basis and all have been approved for at least one or more therapeutic indications by the national medical products administration ( the “ nmpa ” , formerly china food and drug administration , or cfda ) based upon demonstrated safety and efficacy . the 2019 statistical communique on the development of china 's health and health industry shows that by the end of 2019 , the total number of medical and health institutions in china reached 1,007,545 , which represented an increase of 1,345 hospitals and 10,751 primary health care institutions compared with the condition in the previous year . there are 8.807 million beds in the national health care institutions by the end of 2019. public and private hospitals accounted for 72.5 % and 27.5 % , respectively , for the beds in all hospitals . the number of beds in health facilities per 1,000 population increased from 6.03 in 2018 to 6.30 in 2019. drug consistency evaluation is a drug quality requirement in china 's 12th five-year plan for drug safety , that is , the state requires generic drugs to be consistent with the quality and efficacy of their corresponding original drugs . china 's consistency evaluation of generic drugs had continued to proceed in 2020. the supporting policies from central and provincial governments have been constantly issued , including polices regarding consistency evaluation for injectable products . we have always taken the task of facilitating the consistency evaluation as our top priority , and worked on them actively . however , due to the continuous dynamic changes of the detailed policies , future market , expected investment , and return of investment ( “ roi ” ) for each drug 's consistency evaluation , the whole industry , including us , has been making slow progress in terms of the consistency evaluation . 36 we have taken a more cautious and flexible attitude towards the initiating and progressing of an existing product 's consistency evaluation and to cope with the changing macro environment of drug sales in china . on the one hand , since `` 4 + 7 `` ( refers to 11 selected pilot cities , including 4 municipalities and 7 other cities ) trial centralized procurement ( “ cp ” ) activities initiated in 2018 , four rounds of cpcp activities had been carried out by march 2021 , which significantly reduced the price of the drugs that won the bids . on the other hand , the consistency evaluation has been adopted as one of the qualification standards for participating in the cp activities . as a result , we need to balance at least the two factors above before making decisions for any products . we have a product that passed biological equivalents experiments of consistency evaluation in march 2021. we plan to submit relevant documentation and data to nmpa in the near future . in addition , we continue to explore in the field of comprehensive healthcare . comprehensive healthcare is a general concept proposed according to the development of the times , social needs and changes in disease spectrum . according to the outline of `` healthy china 2030 `` issued by chinese government in october 2016 , the total size of china 's health service industry will reach more than rmb 8 trillion by 2020 and rmb 16 trillion by 2030. this industry focuses on people 's daily life , aging and disease , pays attention to all kinds of risk factors and misunderstandings affecting health , and calls for self-health management , and advocates the comprehensive care of the entire process of life . it covers all kinds of health-related information , products and services , as well as actions taken by various organizations to meet the health needs . we launched noni enzyme , a natural , healthy and nutrition-rich food supplement at the end of 2018 , and wash-free sanitizer and masks in 2020 to address the market needs caused by covid-19 in china . in addition , we also actively responded to the market demand for covid-19 related products , and completed a one-time covid-19 tester export transaction in 2020. we will continue to optimize our product structure and actively respond to the current health needs of human beings . market trends as a generic drug company we are presented with a huge domestic market . we believe that through further upgrades and consistency evaluations , we will be able to meet the european and american production standards , which enables us to export our products to overseas markets . in the future , cost management and control ability will gradually become an important factor in determining the competitiveness of generic pharmaceutical enterprises . story_separator_special_tag 38 cost of revenue for the year ended december 31 , 2020 , our cost of revenue was $ 9.0 million , or 82.0 % of total revenue , which represented a decrease of $ 0.4 million from $ 9.4 million , or 86.4 % of total revenue , in 2019. this was mainly due to the impact of the one-time covid-19 tester transaction and the government relief for employees ' social insurance in 2020. gross profit and gross margin gross profit for the year ended december 31 , 2020 was $ 2.0 million , compared to $ 1.5 million in 2019. our gross profit margin in 2020 was 18.0 % compared to 13.6 % in 2019. this increase in our gross profit margin was mainly due to the impact of the one-time covid-19 tester transaction and the government relief for employees ' social insurance in 2020. selling expenses our selling expenses for the year ended december 31 , 2020 were $ 2.2 million , a decrease of $ 0.2 million compared to $ 2.4 million for the year ended december 31 , 2019. selling expenses accounted for 20.4 % of the total revenue in 2020 compared to 21.5 % in 2019. this decrease was mainly due to emergency quarantine measures which reduced business travel and marketing activities due to the covid-19 pandemic . general and administrative expenses our general and administrative expenses for the year ended december 31 , 2020 were $ 1.8 million , as compared to $ 2.3 million in 2019. general and administrative expenses accounted for 16.8 % and 21.0 % of our total revenues in 2020 and 2019 , respectively . this decrease was mainly due to lower travel and office costs due to the impact of covid-19 , as well as offsets for administrative costs from government subsidies . research and development expenses our research and development expenses for the year ended december 31 , 2020 was $ 0.38 million , compared to $ 0.23 million in 2019. research and development expenses accounted for 3.5 % and 2.1 % of our total revenues in 2020 and 2019 , respectively . these expenditures were mainly spent on the consistency evaluation of our existing products . impairment loss there was no impairment loss for the year ended december 31 , 2020. however , we recognized $ 17.02 million impairment loss for the year ended december 31 , 2019 , among which , there was an impairment loss for the advances made to laboratories for the year december 31 , 2019 in the amount of $ 17,015,117. as a pharmaceutical company , we have been focusing on the development and maintenance of our intangible assets , mainly in the form of medical formulas . the consistency evaluations discussed under the “ business overview & recent developments ” section hereof is expected to have a significant impact on all generic products not only in our pipeline , but also throughout the existing chinese market . after evaluating the detailed rules under this policy , in addition to the potential roi and our recent cash flow position , our management made certain assessments regarding the impairment of our intangible assets , and identified four formulas that would likely to be unable to generate positive cash flow in the foreseeable future and therefore recognized impairment loss on them accordingly as of december 31 , 2019. the management determined to impair all advances at december 31 , 2019 , but may resume the development of these formulas in the future if sufficient funding and other favorable conditions arise . bad debt expenses our bad debt expenses for the year ended december 31 , 2020 was $ 115,186 , as compared to $ 3,153 in 2019. this increase was mainly due to the write-off of accounts receivable from some customers who ceased operations due to the covid-19 outbreak in 2020. in general , our normal customer credit or payment terms are 90 days . this has not changed in recent years . due to the peculiar environment affecting the chinese pharmaceutical market , deferred payments to pharmaceutical companies by state-owned hospitals and local medicine distributors are common . the amount of net accounts receivable that were past due ( or the amount of accounts receivable that were more than 180 days old ) was $ 0.06 million and $ 0.15 million as of december 31 , 2020 and 2019 , respectively . 39 the following table illustrates our accounts receivable aging distribution in terms of the percentage of the total accounts receivable as of december 31 , 2020 and 2019 : replace_table_token_3_th our bad debt allowance estimate practice is that we consider accounts receivable balances aged within 180 days current , except for any individual uncollectible account assessed by management . we account for the following respective percentage as bad debt allowance based on age of the accounts receivables : 10 % of accounts receivable that are between 180 days and 365 days old , 70 % of accounts receivable that are between 365 days and 720 days old , and 100 % of accounts receivable that are greater than 720 days old . we recognize bad debt expenses per actual write-offs as well as changes of allowance for doubtful accounts . to the extent that our current allowance for doubtful accounts is higher than that of the previous period , we recognize a bad debt expense for the difference during the current period , and when the current allowance is lower than that of the previous period , we recognize a bad debt credit for the difference . the allowance for doubtful account balances were $ 18.2 million and $ 17.6 million as of december 31 , 2020 and december 31 , 2019 , respectively . the changes in the allowances for doubtful accounts during the years ended december 31 , 2020 and 2019 were as follows : replace_table_token_4_th loss from operations our operating loss for the year ended december 31

