our strategy for achieving profitability is centered upon our ability to utilize chegg services to increase student engagement with our learning platform . we plan to continue to invest in the expansion of our chegg services to provide a more compelling and personalized solution and deepen engagement with students . in addition , we believe that the investments we have made to achieve our current scale will allow us to drive increased operating margins over time that , together with increased contributions of chegg services , will enable us to accomplish profitability and become cash-flow positive in the long-term . our ability to achieve these long-term objectives is subject to numerous risks and uncertainties , including our ability to attract , retain , and increasingly engage the student population , intense competition in our markets , the ability to achieve sufficient contributions to revenue from chegg services and other factors described in greater detail in part i , item 1a , “ risk factors . ” we have presented revenues for our two product lines , chegg services and required materials , based on how students view us and the utilization of our products by them . more detail on our two product lines is discussed in the next two sections titled `` chegg services `` and `` required materials . `` 38 chegg services our chegg services for students primarily includes chegg study , chegg writing , chegg tutors , and chegg math solver . students typically pay to access chegg services such as chegg study on a monthly basis . we also work with leading brands to provide students with discounts , promotions , and other products that , based on student feedback , delight them . in the aggregate , chegg services revenues were 79 % , 73 % and 51 % of net revenues during the years ended december 31 , 2018 , 2017 and 2016 , respectively . required materials our required materials product line includes a revenue share on the rental and sale of print textbooks , as well as revenues from etextbooks . we have entered into agreements with partners to provide our customers a wide variety of print textbooks . these agreements have allowed us to reduce and eliminate the capital requirements and operating expenses that were historically incurred to acquire and maintain a print textbook library . as a result , our revenues include a share on the total transaction amount that we earn upon fulfillment of a rental or sale transaction using print textbooks for which our partners have title and risk of loss , as opposed to the total transaction amount . we offer our etextbooks on a standalone basis or as a rental-equivalent solution and for free to students awaiting the arrival of their print textbook rental for select print textbooks . etextbooks and supplemental course materials are available from approximately 120 publishers as of december 31 , 2018 . we also use our website to rent , sell and source used print textbooks on behalf of our partners . we attract students to our website by offering to buy back their used print textbooks as opposed to selling them back to their campus bookstore . in the aggregate , required materials revenues were 21 % , 27 % , and 49 % of net revenues during the years ended december 31 , 2018 , 2017 and 2016 , respectively . seasonality of our business the recognition of revenues from our chegg services and etextbooks are primarily recognized ratably over the term a student subscribes to our chegg services or rents an etextbook . this has generally resulted in our highest revenues and profitability in the fourth quarter as it reflects more days of the academic year . our variable expenses related to marketing activities remain highest in the first and third quarter such that our profitability may not provide meaningful insight on a sequential basis . as a result of these factors , the most concentrated periods for our revenues and expenses do not necessarily coincide , and comparisons of our historical quarterly operating results on a sequential basis may not provide meaningful insight into our overall financial performance . components of results of operations net revenues we recognize revenues from our chegg services or required materials product lines , net of allowances for refunds or charge backs from our payment processors who process payments from credit cards , debit cards and paypal . during the years ended december 31 , 2018 and 2017 , we no longer recognize rental or sales revenues from the gross amount charged to students for the rental or sale of print textbooks . instead , our services revenues includes a revenue share of the gross amount that we earn upon our partner 's fulfillment of a rental transaction using books for which they have control , including title and risk of loss . revenues from our chegg services product line primarily includes chegg study , chegg writing , chegg tutors , and chegg math solver . chegg services are offered to students primarily through weekly or monthly subscriptions , and we recognize revenues ratably over the respective subscription period . revenues from our required materials product line includes a revenue share on the rental and sale of print textbooks , as well as revenues from etextbooks . the revenue share on the rental and sale of print textbooks is recognized immediately when a book ships to the student . revenues from the rental of etextbooks is recognized ratably over the contractual period , generally two to five months . revenues from the sale of etextbooks is recognized immediately when the etextbook sale occurs . when deciding the most appropriate basis for presenting revenues or costs of revenues , both the legal form and substance of the agreement between us and our business partners are reviewed to determine each party 's respective role in the transaction . story_separator_special_tag gain on liquidation of textbooks we did not record a gain on liquidation of textbooks during the year ended december 31 , 2018 as we liquidated our remaining inventory of print textbooks during the first quarter of 2017. during the years ended december 31 , 2017 and 2016 , we recorded a gain on liquidation of print textbooks of $ 4.8 million and $ 0.7 million , respectively , resulting from proceeds received from liquidation of previously rented print textbooks on our website and through various other liquidation channels . interest expense , net and other income ( expense ) , net the following table sets forth our interest expense , net , and other income ( expense ) , net , for the periods shown ( in thousands , except percentages ) : replace_table_token_7_th _ n/m - not meaningful interest expense , net increased during the year ended december 31 , 2018 compared to the same period in 2017 as a result of the amortization of debt discount and issuance costs and contractual interest expense related to our april 2018 convertible senior notes offering . interest expense , net , decreased during the year ended december 31 , 2017 compared to the same period in 2016 as a result of replacing our previous expired credit facility with a line of credit that carries a lower interest rate . other income ( expense ) , net , was a net income during the years ended december 31 , 2018 and 2017 , primarily attributable to interest earned on investments purchased with the net proceeds from our april 2018 convertible senior notes and 45 2017 follow-on offerings . other income ( expense ) , net , was a net expense during the year ended december 31 , 2016 , primarily attributable to the accretion of the deferred cash consideration as a result of our acquisition of imagine easy solutions . provision for income taxes the following table sets forth our provision for income taxes for the periods shown ( in thousands , except percentages ) : replace_table_token_8_th we recorded an income tax provision of approximately $ 1.4 million , $ 1.8 million , and $ 1.7 million for the years ended december 31 , 2018 , 2017 , and 2016 , respectively , which was primarily due to state and foreign income tax expense and federal and state tax expense related to the tax amortization of acquired indefinite lived intangible assets . liquidity and capital resources as of december 31 , 2018 , our principal sources of liquidity were cash , cash equivalents , and investments totaling $ 484.1 million , which were held for working capital purposes . the substantial majority of our net revenues are from e-commerce transactions with students , which are settled immediately through payment processors , as opposed to our accounts payable , which are settled based on contractual payment terms with our suppliers . in april 2018 , we closed an offering of our 0.25 % convertible senior notes ( the notes ) generating net proceeds of approximately $ 335.6 million , after deducting the initial purchasers ' discount and estimated offering expenses payable by us . the notes mature on may 15 , 2023 unless converted , redeemed or repurchased in accordance with their terms prior to such date . as of december 31 , 2018 , we have incurred cumulative losses of $ 406.6 million from our operations and we expect to incur additional losses in the future . our operations have been financed primarily by our initial public offering of our common stock ( ipo ) , our 2017 follow-on public offering , our 2018 convertible senior notes offering , and cash generated from operations . we believe that our existing sources of liquidity will be sufficient to fund our operations and debt service obligations for at least the next 12 months . our future capital requirements will depend on many factors including our rate of revenue growth , our investments in research and development activities , our acquisition of new products and services and our sales and marketing activities . to the extent that existing cash and cash from operations are insufficient to fund our future activities , we may need to raise additional funds through public or private equity or debt financing . additional funds may not be available on terms favorable to us or at all . if adequate funds are not available on acceptable terms , or at all , we may be unable to adequately fund our business plans and it could have a negative effect on our business , operating cash flows and financial condition . most of our cash is held in the united states . as of december 31 , 2018 , our foreign subsidiaries held an insignificant amount of cash in foreign jurisdictions . we currently do not intend or foresee a need to repatriate some of these foreign funds however , as a result of the tax cuts and jobs act we anticipate the u.s. federal impact to be minimal if these foreign funds are repatriated . in addition , based on our current and future needs , we believe our current funding and capital resources for our international operations are adequate . the following table sets forth our cash flows ( in thousands ) : replace_table_token_9_th * adjusted to reflect the adoption of asu 2016-18. see item 8 , note 2 for more information . cash flows from operating activities although we incurred net losses during the years ended december 31 , 2018 , 2017 and 2016 , our net losses were fully offset by non-cash expenditures such as other depreciation and amortization expense , share-based compensation expense , and 46 amortization of debt discount and issuance costs expense . story_separator_special_tag under stock plans of $ 23.7 million partially offset by the payment of $ 20.1 million in taxes related to the net share settlement of equity awards and the payment

net cash provided by operating activities during the year ended december 31 , 2018 was $ 75.1 million . our net loss of $ 14.9 million was offset by significant non-cash operating expenses , including other depreciation and amortization expense of $ 22.8 million , share-based compensation expense of $ 52.0 million , and the amortization of debt discount and issuance costs expense of $ 10.5 million . net cash provided by operating activities during the year ended december 31 , 2017 was $ 51.6 million . our net loss of $ 20.3 million was offset by significant non-cash operating expenses , including other depreciation and amortization expense of $ 19.3 million , share-based compensation expense of $ 38.4 million , and the change in our prepaid and other current assets of $ 13.6 million , which was primarily driven by the decline in the reimbursement balance from ingram as they moved to normal payment terms in 2017. net cash provided by operating activities during the year ended december 31 , 2016 was $ 24.3 million . our net loss of $ 42.2 million was offset by significant non-cash operating expenses , including print textbook library depreciation expense of $ 9.3 million , other depreciation and amortization expense of $ 14.6 million , share-based compensation expense of $ 41.8 million and loss from write-offs of print textbooks of $ 1.1 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.
     ```net cash provided by operating activities during the year ended december 31 , 2018 was $ 75.1 million . our net loss of $ 14.9 million was offset by significant non-cash operating expenses , including other depreciation and amortization expense of $ 22.8 million , share-based compensation expense of $ 52.0 million , and the amortization of debt discount and issuance costs expense of $ 10.5 million . net cash provided by operating activities during the year ended december 31 , 2017 was $ 51.6 million . our net loss of $ 20.3 million was offset by significant non-cash operating expenses , including other depreciation and amortization expense of $ 19.3 million , share-based compensation expense of $ 38.4 million , and the change in our prepaid and other current assets of $ 13.6 million , which was primarily driven by the decline in the reimbursement balance from ingram as they moved to normal payment terms in 2017. net cash provided by operating activities during the year ended december 31 , 2016 was $ 24.3 million . our net loss of $ 42.2 million was offset by significant non-cash operating expenses , including print textbook library depreciation expense of $ 9.3 million , other depreciation and amortization expense of $ 14.6 million , share-based compensation expense of $ 41.8 million and loss from write-offs of print textbooks of $ 1.1 million .
```    
 Suspicious Activity Report : our strategy for achieving profitability is centered upon our ability to utilize chegg services to increase student engagement with our learning platform . we plan to continue to invest in the expansion of our chegg services to provide a more compelling and personalized solution and deepen engagement with students . in addition , we believe that the investments we have made to achieve our current scale will allow us to drive increased operating margins over time that , together with increased contributions of chegg services , will enable us to accomplish profitability and become cash-flow positive in the long-term . our ability to achieve these long-term objectives is subject to numerous risks and uncertainties , including our ability to attract , retain , and increasingly engage the student population , intense competition in our markets , the ability to achieve sufficient contributions to revenue from chegg services and other factors described in greater detail in part i , item 1a , “ risk factors . ” we have presented revenues for our two product lines , chegg services and required materials , based on how students view us and the utilization of our products by them . more detail on our two product lines is discussed in the next two sections titled `` chegg services `` and `` required materials . `` 38 chegg services our chegg services for students primarily includes chegg study , chegg writing , chegg tutors , and chegg math solver . students typically pay to access chegg services such as chegg study on a monthly basis . we also work with leading brands to provide students with discounts , promotions , and other products that , based on student feedback , delight them . in the aggregate , chegg services revenues were 79 % , 73 % and 51 % of net revenues during the years ended december 31 , 2018 , 2017 and 2016 , respectively . required materials our required materials product line includes a revenue share on the rental and sale of print textbooks , as well as revenues from etextbooks . we have entered into agreements with partners to provide our customers a wide variety of print textbooks . these agreements have allowed us to reduce and eliminate the capital requirements and operating expenses that were historically incurred to acquire and maintain a print textbook library . as a result , our revenues include a share on the total transaction amount that we earn upon fulfillment of a rental or sale transaction using print textbooks for which our partners have title and risk of loss , as opposed to the total transaction amount . we offer our etextbooks on a standalone basis or as a rental-equivalent solution and for free to students awaiting the arrival of their print textbook rental for select print textbooks . etextbooks and supplemental course materials are available from approximately 120 publishers as of december 31 , 2018 . we also use our website to rent , sell and source used print textbooks on behalf of our partners . we attract students to our website by offering to buy back their used print textbooks as opposed to selling them back to their campus bookstore . in the aggregate , required materials revenues were 21 % , 27 % , and 49 % of net revenues during the years ended december 31 , 2018 , 2017 and 2016 , respectively . seasonality of our business the recognition of revenues from our chegg services and etextbooks are primarily recognized ratably over the term a student subscribes to our chegg services or rents an etextbook . this has generally resulted in our highest revenues and profitability in the fourth quarter as it reflects more days of the academic year . our variable expenses related to marketing activities remain highest in the first and third quarter such that our profitability may not provide meaningful insight on a sequential basis . as a result of these factors , the most concentrated periods for our revenues and expenses do not necessarily coincide , and comparisons of our historical quarterly operating results on a sequential basis may not provide meaningful insight into our overall financial performance . components of results of operations net revenues we recognize revenues from our chegg services or required materials product lines , net of allowances for refunds or charge backs from our payment processors who process payments from credit cards , debit cards and paypal . during the years ended december 31 , 2018 and 2017 , we no longer recognize rental or sales revenues from the gross amount charged to students for the rental or sale of print textbooks . instead , our services revenues includes a revenue share of the gross amount that we earn upon our partner 's fulfillment of a rental transaction using books for which they have control , including title and risk of loss . revenues from our chegg services product line primarily includes chegg study , chegg writing , chegg tutors , and chegg math solver . chegg services are offered to students primarily through weekly or monthly subscriptions , and we recognize revenues ratably over the respective subscription period . revenues from our required materials product line includes a revenue share on the rental and sale of print textbooks , as well as revenues from etextbooks . the revenue share on the rental and sale of print textbooks is recognized immediately when a book ships to the student . revenues from the rental of etextbooks is recognized ratably over the contractual period , generally two to five months . revenues from the sale of etextbooks is recognized immediately when the etextbook sale occurs . when deciding the most appropriate basis for presenting revenues or costs of revenues , both the legal form and substance of the agreement between us and our business partners are reviewed to determine each party 's respective role in the transaction . story_separator_special_tag gain on liquidation of textbooks we did not record a gain on liquidation of textbooks during the year ended december 31 , 2018 as we liquidated our remaining inventory of print textbooks during the first quarter of 2017. during the years ended december 31 , 2017 and 2016 , we recorded a gain on liquidation of print textbooks of $ 4.8 million and $ 0.7 million , respectively , resulting from proceeds received from liquidation of previously rented print textbooks on our website and through various other liquidation channels . interest expense , net and other income ( expense ) , net the following table sets forth our interest expense , net , and other income ( expense ) , net , for the periods shown ( in thousands , except percentages ) : replace_table_token_7_th _ n/m - not meaningful interest expense , net increased during the year ended december 31 , 2018 compared to the same period in 2017 as a result of the amortization of debt discount and issuance costs and contractual interest expense related to our april 2018 convertible senior notes offering . interest expense , net , decreased during the year ended december 31 , 2017 compared to the same period in 2016 as a result of replacing our previous expired credit facility with a line of credit that carries a lower interest rate . other income ( expense ) , net , was a net income during the years ended december 31 , 2018 and 2017 , primarily attributable to interest earned on investments purchased with the net proceeds from our april 2018 convertible senior notes and 45 2017 follow-on offerings . other income ( expense ) , net , was a net expense during the year ended december 31 , 2016 , primarily attributable to the accretion of the deferred cash consideration as a result of our acquisition of imagine easy solutions . provision for income taxes the following table sets forth our provision for income taxes for the periods shown ( in thousands , except percentages ) : replace_table_token_8_th we recorded an income tax provision of approximately $ 1.4 million , $ 1.8 million , and $ 1.7 million for the years ended december 31 , 2018 , 2017 , and 2016 , respectively , which was primarily due to state and foreign income tax expense and federal and state tax expense related to the tax amortization of acquired indefinite lived intangible assets . liquidity and capital resources as of december 31 , 2018 , our principal sources of liquidity were cash , cash equivalents , and investments totaling $ 484.1 million , which were held for working capital purposes . the substantial majority of our net revenues are from e-commerce transactions with students , which are settled immediately through payment processors , as opposed to our accounts payable , which are settled based on contractual payment terms with our suppliers . in april 2018 , we closed an offering of our 0.25 % convertible senior notes ( the notes ) generating net proceeds of approximately $ 335.6 million , after deducting the initial purchasers ' discount and estimated offering expenses payable by us . the notes mature on may 15 , 2023 unless converted , redeemed or repurchased in accordance with their terms prior to such date . as of december 31 , 2018 , we have incurred cumulative losses of $ 406.6 million from our operations and we expect to incur additional losses in the future . our operations have been financed primarily by our initial public offering of our common stock ( ipo ) , our 2017 follow-on public offering , our 2018 convertible senior notes offering , and cash generated from operations . we believe that our existing sources of liquidity will be sufficient to fund our operations and debt service obligations for at least the next 12 months . our future capital requirements will depend on many factors including our rate of revenue growth , our investments in research and development activities , our acquisition of new products and services and our sales and marketing activities . to the extent that existing cash and cash from operations are insufficient to fund our future activities , we may need to raise additional funds through public or private equity or debt financing . additional funds may not be available on terms favorable to us or at all . if adequate funds are not available on acceptable terms , or at all , we may be unable to adequately fund our business plans and it could have a negative effect on our business , operating cash flows and financial condition . most of our cash is held in the united states . as of december 31 , 2018 , our foreign subsidiaries held an insignificant amount of cash in foreign jurisdictions . we currently do not intend or foresee a need to repatriate some of these foreign funds however , as a result of the tax cuts and jobs act we anticipate the u.s. federal impact to be minimal if these foreign funds are repatriated . in addition , based on our current and future needs , we believe our current funding and capital resources for our international operations are adequate . the following table sets forth our cash flows ( in thousands ) : replace_table_token_9_th * adjusted to reflect the adoption of asu 2016-18. see item 8 , note 2 for more information . cash flows from operating activities although we incurred net losses during the years ended december 31 , 2018 , 2017 and 2016 , our net losses were fully offset by non-cash expenditures such as other depreciation and amortization expense , share-based compensation expense , and 46 amortization of debt discount and issuance costs expense . story_separator_special_tag under stock plans of $ 23.7 million partially offset by the payment of $ 20.1 million in taxes related to the net share settlement of equity awards and the payment

