in may 2016 , we acquired imagine easy solutions , llc , a privately held online learning company based in new york that provides a portfolio of online writing tools . we anticipate this acquisition to enhance our ability to acquire new students , increase the value to our existing students , and have a meaningful and positive impact on their outcomes . further , we believe this expanded and deeper penetration of the student demographic will allow us to drive further growth in our existing chegg services . in addition , we believe that these 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 products , will enable us to accomplish profitability and become cash-flow positive for 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 . ” 40 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 . chegg services includes our products and services we provide to supplement the requirements and help students with their coursework . chegg services also includes our marketing services which help to complete our offering of services to students . required materials includes all products that are essential for students to meet the requirements of their coursework . more detail on our two product lines is discussed in the next two sections titled `` chegg services `` and `` required materials . `` chegg services our chegg services for students primarily includes our chegg study service , our chegg tutors service , and our writing tools service . we offer enrollment marketing services to colleges , through our strategic partnership with nrccua announced in january 2017 , allowing them to reach interested college-bound high school students that use our college admissions and scholarship services . we also work with leading brands , such as proctor & gamble , starbucks , the truth , microsoft , best buy , directtv , bare escentuals , and shutterfly , to provide students with discounts , promotions , and other products that , based on student feedback , delight them . for example , for proctor & gamble , we inserted free laundry care samples and for starbucks , we inserted free drinks in our textbook rental shipments to students . all of our brand advertising services and the discounts , promotions , and other products provided to students are paid for by the brands . we additionally provide internship services and our test prep service currently covering the act and sat exams . students typically pay to access chegg services such as chegg study on a monthly or annual basis , while colleges subscribe to our enrollment marketing services and brands pay us depending on the nature of the campaign . in the aggregate , chegg services revenues were 51 % , 31 % and 22 % of net revenues during the years ended december 31 , 2016 , 2015 and 2014 , respectively . required materials our required materials product line includes the rental and sale of print textbooks and etextbooks as well as the commission we receive from ingram . as of november 2016 , we no longer rent our print textbooks and therefore all revenues from print textbook rentals from this date forward are commission-based . our web-based , multiplatform etextbook reader , etextbooks and supplemental course materials are available from approximately 120 publishers as of december 31 , 2016 . we offer our etextbook reader on a standalone basis or as a rental-equivalent solution and for free to students awaiting the arrival of their print textbook rental . this product line has historically been highly capital intensive due to the resources required to maintain a print textbook rental library . however , as a result of our strategic partnership with ingram , we have exited our warehouse facilities in kentucky and transitioned our print textbook library to ingram 's facilities , which has helped to free up resources historically required by this product line . we have continued to liquidate our print textbook library through the normal course of our operations and maintain a minimal print textbook rental library as of december 31 , 2016 . we will continue to liquidate our remaining print textbook library inventory in the first half of 2017. we have historically capitalized the investment in our print textbook library and recorded depreciation expense in cost of revenues over its useful life using an estimated liquidation value . during the years ended december 31 , 2016 and 2015 , our purchases of print textbooks , net of proceeds from textbook liquidation was an inflow of $ 24.8 million and $ 6.0 million , respectively , and an outflow during the year ended december 31 , 2014 of $ 54.7 million . in the years ended december 31 , 2016 and 2015 , our purchases of print textbooks significantly decreased , and were more than offset by the proceeds received from liquidations of textbooks from our print textbook library . this was a result of our strategic partnership with ingram as we are no longer purchased print textbooks for rental . we use our website to liquidate print textbooks from our remaining print textbook library , which allows us to generate greater recovery on our print textbooks compared to bulk liquidations , while at the same time providing students substantial savings over the retail price of a new book . story_separator_special_tag 45 results of operations the following table summarizes our historical consolidated statements of operations ( in thousands , except percentage of total net revenues ) : replace_table_token_4_th 46 year ended december 31 , 2016 , 2015 and 2014 net revenues net revenues in the year ended december 31 , 2016 decreased $ 47.3 million , or 16 % , compared to the same period in 2015 . rental revenues decreased $ 80.5 million or 67 % , while services revenues increased $ 49.3 million , or 37 % , and sales revenues decreased $ 16.0 million , or 33 % . net revenues in the year ended december 31 , 2015 decreased $ 3.5 million , or 1 % , compared to the same period in 2014. rental revenues decreased $ 61.2 million or 34 % , while services revenues increased $ 44.5 million , or 51 % , and sales revenues increased $ 13.2 million , or 37 % . the decrease in rental revenues during the years ended december 31 , 2016 and 2015 was due to our strategic partnership with ingram . as a result of our strategic partnership , our rental revenues are increasingly classified as services revenues to represent the commission on the total revenues that we earn from ingram upon their fulfillment of a rental transaction using books for which ingram has title and risk of loss rather than recognizing rental revenues from transactions using our print textbooks . the increase in services revenues during the years ended december 31 , 2016 and 2015 was driven primarily from growth across our other offerings for students which included increased revenues from chegg study and our various acquisitions in 2014 and 2016 as well as an increase in the commissions earned from ingram . the decrease in sales revenues during the year ended december 31 , 2016 and the increase in sales revenues during the year ended december 31 , 2015 was driven by sales of print textbooks through our website on a just-in-time basis . the following table sets forth our total net revenues for the periods shown for our chegg services and required materials product lines ( dollars in thousands ) : replace_table_token_5_th chegg services revenues increased $ 35.1 million , or 37 % , in the year ended december 31 , 2016 , compared to the same period in 2015 due to growth in subscribers for our chegg study and chegg tutors services as well as revenues from our acquisition of imagine easy in the second quarter of 2016. chegg services revenues represented 51 % and 31 % of net revenues during the years ended december 31 , 2016 and 2015 , respectively . required materials revenues decreased $ 82.3 million , or 40 % , in the year ended december 31 , 2016 compared to the same period in 2015 primarily due to our strategic partnership with ingram . our required materials revenues are increasingly comprised of a commission earned from ingram rather than the full revenues from a print textbook rental transaction . required materials revenues decreased throughout 2016 and we fully transitioned new investments in the print textbook library and logistics and fulfillment for print textbook rental and sale orders to ingram . required materials revenues represented 49 % and 69 % of net revenues during the years ended december 31 , 2016 and 2015 , respectively . chegg services revenues increased $ 26.2 million , or 38 % , in the year ended december 31 , 2015 , compared to the same period in 2014 due to growth in subscriptions for our chegg study service . chegg services represented 31 % and 22 % of net revenues during the years ended december 31 , 2015 and 2014 , respectively . required materials revenues decreased $ 29.6 million , or 13 % , in the year ended december 31 , 2015 compared to the same period in 2014 primarily due to our partnership with ingram . required materials revenues represented 69 % and 78 % of net revenues during the years ended december 31 , 2015 and 2014 , respectively . 47 cost of revenues the following table sets forth our cost of revenues for the periods shown ( dollars in thousands ) : replace_table_token_6_th cost of revenues in the year ended december 31 , 2016 decreased by $ 70.2 million , or 37 % , compared to the same period in 2015 . the decrease in absolute dollars and as a percentage of revenues for the year ended december 31 , 2016 was primarily due to a decrease in textbook depreciation of $ 34.3 million , lower order fulfillment costs of $ 18.3 million , lower write-offs related to our print textbook library of $ 4.2 million , lower warehouse personnel costs of $ 3.1 million and lower cost of print textbooks sold of $ 16.4 million . these savings were partially offset by higher amortization of digital content of $ 5.3 million . as a result , gross margins increased to 53 % in the year ended december 31 , 2016 , from 37 % in the year ended december 31 , 2015 . cost of revenues in the year ended december 31 , 2015 decreased by $ 21.1 million , or 10 % , compared to the same period in 2014. the decrease in absolute dollars and as a percentage of revenues for the year ended december 31 , 2015 was primarily due to a decrease in textbook depreciation of $ 26.6 million , write-offs related to our print textbook library of $ 5.2 million and lower warehouse personnel costs of $ 5.6 million . these savings were partially offset by higher cost of print textbooks sold of $ 15.5 million and higher amortization of digital content of $ 1.6 million . as a result , gross margins increased to 37 % in the year ended december 31 , 2015 , from 31 % in the year

net cash provided by operating activities during the year ended december 31 , 2016 was $ 24.9 million . our net loss of $ 42.2 million was offset by significant non-cash operating expenses , including print textbook library depreciation expense of 51 $ 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 . net cash used in operating activities during the year ended december 31 , 2015 was $ 0.1 million . our net loss of $ 59.2 million was increased by the change in our prepaid expenses and other current assets of $ 27.9 million and partially offset by significant non-cash operating expenses , including print textbook library depreciation expense of $ 43.6 million , other depreciation and amortization expense of $ 11.7 million , share-based compensation expense of $ 38.8 million and loss from write-offs of print textbooks of $ 5.3 million . during the year ended december 31 , 2015 , we saw a decline in our textbook depreciation expense and an increase in the change of our prepaid expenses and other current assets , which was a result of our strategic partnership with ingram , where we are no longer making investments in our print textbook library yet continue to buy books on ingram 's behalf , while providing them with extended payment terms .


 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 , 2016 was $ 24.9 million . our net loss of $ 42.2 million was offset by significant non-cash operating expenses , including print textbook library depreciation expense of 51 $ 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 . net cash used in operating activities during the year ended december 31 , 2015 was $ 0.1 million . our net loss of $ 59.2 million was increased by the change in our prepaid expenses and other current assets of $ 27.9 million and partially offset by significant non-cash operating expenses , including print textbook library depreciation expense of $ 43.6 million , other depreciation and amortization expense of $ 11.7 million , share-based compensation expense of $ 38.8 million and loss from write-offs of print textbooks of $ 5.3 million . during the year ended december 31 , 2015 , we saw a decline in our textbook depreciation expense and an increase in the change of our prepaid expenses and other current assets , which was a result of our strategic partnership with ingram , where we are no longer making investments in our print textbook library yet continue to buy books on ingram 's behalf , while providing them with extended payment terms .
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 Suspicious Activity Report : in may 2016 , we acquired imagine easy solutions , llc , a privately held online learning company based in new york that provides a portfolio of online writing tools . we anticipate this acquisition to enhance our ability to acquire new students , increase the value to our existing students , and have a meaningful and positive impact on their outcomes . further , we believe this expanded and deeper penetration of the student demographic will allow us to drive further growth in our existing chegg services . in addition , we believe that these 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 products , will enable us to accomplish profitability and become cash-flow positive for 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 . ” 40 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 . chegg services includes our products and services we provide to supplement the requirements and help students with their coursework . chegg services also includes our marketing services which help to complete our offering of services to students . required materials includes all products that are essential for students to meet the requirements of their coursework . more detail on our two product lines is discussed in the next two sections titled `` chegg services `` and `` required materials . `` chegg services our chegg services for students primarily includes our chegg study service , our chegg tutors service , and our writing tools service . we offer enrollment marketing services to colleges , through our strategic partnership with nrccua announced in january 2017 , allowing them to reach interested college-bound high school students that use our college admissions and scholarship services . we also work with leading brands , such as proctor & gamble , starbucks , the truth , microsoft , best buy , directtv , bare escentuals , and shutterfly , to provide students with discounts , promotions , and other products that , based on student feedback , delight them . for example , for proctor & gamble , we inserted free laundry care samples and for starbucks , we inserted free drinks in our textbook rental shipments to students . all of our brand advertising services and the discounts , promotions , and other products provided to students are paid for by the brands . we additionally provide internship services and our test prep service currently covering the act and sat exams . students typically pay to access chegg services such as chegg study on a monthly or annual basis , while colleges subscribe to our enrollment marketing services and brands pay us depending on the nature of the campaign . in the aggregate , chegg services revenues were 51 % , 31 % and 22 % of net revenues during the years ended december 31 , 2016 , 2015 and 2014 , respectively . required materials our required materials product line includes the rental and sale of print textbooks and etextbooks as well as the commission we receive from ingram . as of november 2016 , we no longer rent our print textbooks and therefore all revenues from print textbook rentals from this date forward are commission-based . our web-based , multiplatform etextbook reader , etextbooks and supplemental course materials are available from approximately 120 publishers as of december 31 , 2016 . we offer our etextbook reader on a standalone basis or as a rental-equivalent solution and for free to students awaiting the arrival of their print textbook rental . this product line has historically been highly capital intensive due to the resources required to maintain a print textbook rental library . however , as a result of our strategic partnership with ingram , we have exited our warehouse facilities in kentucky and transitioned our print textbook library to ingram 's facilities , which has helped to free up resources historically required by this product line . we have continued to liquidate our print textbook library through the normal course of our operations and maintain a minimal print textbook rental library as of december 31 , 2016 . we will continue to liquidate our remaining print textbook library inventory in the first half of 2017. we have historically capitalized the investment in our print textbook library and recorded depreciation expense in cost of revenues over its useful life using an estimated liquidation value . during the years ended december 31 , 2016 and 2015 , our purchases of print textbooks , net of proceeds from textbook liquidation was an inflow of $ 24.8 million and $ 6.0 million , respectively , and an outflow during the year ended december 31 , 2014 of $ 54.7 million . in the years ended december 31 , 2016 and 2015 , our purchases of print textbooks significantly decreased , and were more than offset by the proceeds received from liquidations of textbooks from our print textbook library . this was a result of our strategic partnership with ingram as we are no longer purchased print textbooks for rental . we use our website to liquidate print textbooks from our remaining print textbook library , which allows us to generate greater recovery on our print textbooks compared to bulk liquidations , while at the same time providing students substantial savings over the retail price of a new book . story_separator_special_tag 45 results of operations the following table summarizes our historical consolidated statements of operations ( in thousands , except percentage of total net revenues ) : replace_table_token_4_th 46 year ended december 31 , 2016 , 2015 and 2014 net revenues net revenues in the year ended december 31 , 2016 decreased $ 47.3 million , or 16 % , compared to the same period in 2015 . rental revenues decreased $ 80.5 million or 67 % , while services revenues increased $ 49.3 million , or 37 % , and sales revenues decreased $ 16.0 million , or 33 % . net revenues in the year ended december 31 , 2015 decreased $ 3.5 million , or 1 % , compared to the same period in 2014. rental revenues decreased $ 61.2 million or 34 % , while services revenues increased $ 44.5 million , or 51 % , and sales revenues increased $ 13.2 million , or 37 % . the decrease in rental revenues during the years ended december 31 , 2016 and 2015 was due to our strategic partnership with ingram . as a result of our strategic partnership , our rental revenues are increasingly classified as services revenues to represent the commission on the total revenues that we earn from ingram upon their fulfillment of a rental transaction using books for which ingram has title and risk of loss rather than recognizing rental revenues from transactions using our print textbooks . the increase in services revenues during the years ended december 31 , 2016 and 2015 was driven primarily from growth across our other offerings for students which included increased revenues from chegg study and our various acquisitions in 2014 and 2016 as well as an increase in the commissions earned from ingram . the decrease in sales revenues during the year ended december 31 , 2016 and the increase in sales revenues during the year ended december 31 , 2015 was driven by sales of print textbooks through our website on a just-in-time basis . the following table sets forth our total net revenues for the periods shown for our chegg services and required materials product lines ( dollars in thousands ) : replace_table_token_5_th chegg services revenues increased $ 35.1 million , or 37 % , in the year ended december 31 , 2016 , compared to the same period in 2015 due to growth in subscribers for our chegg study and chegg tutors services as well as revenues from our acquisition of imagine easy in the second quarter of 2016. chegg services revenues represented 51 % and 31 % of net revenues during the years ended december 31 , 2016 and 2015 , respectively . required materials revenues decreased $ 82.3 million , or 40 % , in the year ended december 31 , 2016 compared to the same period in 2015 primarily due to our strategic partnership with ingram . our required materials revenues are increasingly comprised of a commission earned from ingram rather than the full revenues from a print textbook rental transaction . required materials revenues decreased throughout 2016 and we fully transitioned new investments in the print textbook library and logistics and fulfillment for print textbook rental and sale orders to ingram . required materials revenues represented 49 % and 69 % of net revenues during the years ended december 31 , 2016 and 2015 , respectively . chegg services revenues increased $ 26.2 million , or 38 % , in the year ended december 31 , 2015 , compared to the same period in 2014 due to growth in subscriptions for our chegg study service . chegg services represented 31 % and 22 % of net revenues during the years ended december 31 , 2015 and 2014 , respectively . required materials revenues decreased $ 29.6 million , or 13 % , in the year ended december 31 , 2015 compared to the same period in 2014 primarily due to our partnership with ingram . required materials revenues represented 69 % and 78 % of net revenues during the years ended december 31 , 2015 and 2014 , respectively . 47 cost of revenues the following table sets forth our cost of revenues for the periods shown ( dollars in thousands ) : replace_table_token_6_th cost of revenues in the year ended december 31 , 2016 decreased by $ 70.2 million , or 37 % , compared to the same period in 2015 . the decrease in absolute dollars and as a percentage of revenues for the year ended december 31 , 2016 was primarily due to a decrease in textbook depreciation of $ 34.3 million , lower order fulfillment costs of $ 18.3 million , lower write-offs related to our print textbook library of $ 4.2 million , lower warehouse personnel costs of $ 3.1 million and lower cost of print textbooks sold of $ 16.4 million . these savings were partially offset by higher amortization of digital content of $ 5.3 million . as a result , gross margins increased to 53 % in the year ended december 31 , 2016 , from 37 % in the year ended december 31 , 2015 . cost of revenues in the year ended december 31 , 2015 decreased by $ 21.1 million , or 10 % , compared to the same period in 2014. the decrease in absolute dollars and as a percentage of revenues for the year ended december 31 , 2015 was primarily due to a decrease in textbook depreciation of $ 26.6 million , write-offs related to our print textbook library of $ 5.2 million and lower warehouse personnel costs of $ 5.6 million . these savings were partially offset by higher cost of print textbooks sold of $ 15.5 million and higher amortization of digital content of $ 1.6 million . as a result , gross margins increased to 37 % in the year ended december 31 , 2015 , from 31 % in the year

