for the years ended december 31 , 2018 , 2017 and 2016 , the vast majority of our total revenues were generated in the u.s. and canada , although we expect the percentage of our total revenues derived outside of the u.s. and canada to grow as we continue to expand internationally . the growth of our business and our future success depend on many factors , including our ability to expand our customer base to medium-sized and larger customers , continue to innovate , grow revenues from our existing customer base , expand our distribution channels , and scale internationally . while these areas represent significant opportunities for us , they also pose risks and challenges that we must address in order to sustain the growth of our business and improve our operating results . we have experienced significant growth in recent periods , with total revenues of $ 673.6 million , $ 503.6 million and $ 380.4 million , in the years ended december 31 , 2018 , 2017 and 2016 , respectively , representing year-over-year increases of 34 % and 32 % , respectively . we have continued to make significant expenditures and investments , including those in sales and marketing , research and development , infrastructure and operations and incurred net losses of $ 26.2 million , $ 4.2 million , and $ 16.2 million in the years ended december 31 , 2018 , 2017 and 2016 , respectively . 47 key business metrics in addition to united states generally accepted accounting principles ( “ u.s . gaap ” ) and financial measures such as total revenues , gross margin , and cash flows from operations , we regularly review a number of key business metrics to evaluate growth trends , measure our performance , and make strategic decisions . we discuss revenues and gross margin under “ results of operations ” and cash flow from operations under “ liquidity and capital resources . ” other key business metrics are discussed below . annualized exit monthly recurring subscriptions we believe that our annualized exit monthly recurring subscriptions ( “ arr ” ) is a leading indicator of our anticipated subscriptions revenues . we believe that trends in revenue are important to understanding the overall health of our business , and we use these trends in order to formulate financial projections and make strategic business decisions . our arr equals our monthly recurring subscriptions multiplied by 12. our monthly recurring subscriptions equals the monthly value of all customer recurring charges contracted at the end of a given month . for example , our monthly recurring subscriptions at december 31 , 2018 were $ 60.5 million . as such , our arr at december 31 , 2018 was $ 725.8 million compared to $ 546.4 million at december 31 , 2017. ringcentral office annualized exit monthly recurring subscriptions we calculate our ringcentral office annualized exit monthly recurring subscriptions ( “ office arr ” ) in the same manner as we calculate our arr , except that only customer subscriptions from ringcentral office , ringcentral contact center , and ringcentral engage customers are included when determining monthly recurring subscriptions for the purposes of calculating this key business metric . we believe that trends in revenue with respect to these products are important to the understanding of the overall health of our business , and we use these trends in order to formulate financial projections and make strategic business decisions . our office arr at december 31 , 2018 was $ 644.1 million compared to $ 466.2 million at december 31 , 2017. net monthly subscription dollar retention rate we believe that our net monthly subscription dollar retention rate provides insight into our ability to retain and grow software subscriptions revenue , as well as our customers ' potential long-term value to us . we believe that our ability to retain our customers and expand their use of our solutions over time is a leading indicator of the stability of our revenue base and we use these trends in order to formulate financial projections and make strategic business decisions . we define our net monthly subscription dollar retention rate as ( i ) one plus ( ii ) the quotient of dollar net change divided by average dollar monthly recurring subscriptions . we define dollar net change as the quotient of ( i ) the difference of our monthly recurring subscriptions at the end of a period minus our monthly recurring subscriptions at the beginning of a period minus our monthly recurring subscriptions at the end of the period from new customers , we added during the period , ( ii ) all divided by the number of months in the period . we define our average monthly recurring subscriptions as the average of the monthly recurring subscriptions at the beginning and end of the measurement period . for example , if our monthly recurring subscriptions were $ 118 at the end of a quarterly period and $ 100 at the beginning of period , and $ 20 at the end of the period from new customers we added during the period , then the dollar net change would be equal to ( $ 0.67 ) , or the amount equal to the difference of $ 118 minus $ 100 minus $ 20 , all divided by three months . our average monthly recurring subscriptions would equal $ 109 , or the sum of $ 100 plus $ 118 , divided by two . our net monthly subscription dollar retention rate would then equal 99.4 % , or approximately 99 % , or one plus the quotient of the dollar net change divided by the average monthly recurring subscriptions . story_separator_special_tag the increase in personnel costs was primarily due headcount of growth and higher share-based compensation expense of $ 5.1 million . the increases in sales and marketing headcount and other expense categories were necessary to support our growth strategy to acquire new customers with a focus on larger customers and establish brand recognition to achieve greater penetration in the north american and international markets . additionally , we expect sales and marketing expenses to continue to increase in absolute dollars as we continue to expand our presence in north america , europe , and other markets . general and administrative replace_table_token_8_th general and administrative expenses increased by $ 30.5 million , or 42 % , from fiscal year 2017 to 2018 primarily due to increases in personnel costs of $ 21.6 million , legal and professional fees of $ 4.8 million and acquisition related costs of $ 2.5 million . the increase in personnel costs was primarily driven by headcount growth and higher share-based compensation expense of $ 8.0 million . general and administrative expenses increased by $ 16.9 million , or 30 % , from fiscal year 2016 to 2017 primarily due to increases in personnel costs of $ 13.1 million , travel and overhead costs of $ 1.5 million , and professional fees of $ 1.4 million . the increase in personnel costs was primarily driven by headcount growth and higher share-based compensation expense of $ 3.3 million . we expect general and administrative expenses to continue to increase in absolute dollars as we continue to make additional investments in processes , systems , and personnel to support our anticipated revenue growth . 54 other income ( e xpense ) , net replace_table_token_9_th other expense , net increased by $ 11.0 million from fiscal year 2017 to 2018 , primarily due to a $ 16.0 million increase in interest expense resulting from the amortization of debt discount and issuance costs of our 0 % convertible senior notes due 2023 ( “ notes ” ) , and foreign currency losses of $ 1.9 million . this was partially offset by a $ 6.8 million increase in interest income on our cash and cash equivalents . other income , net increased by $ 4.5 million from fiscal year 2016 to 2017 primarily due to foreign currency gains driven by the significant increase in the canadian dollar relative to the u.s. dollar and lower interest expense of $ 0.6 million due to the repayment of our debt in february 2017. liquidity and capital resources as of december 31 , 2018 and 2017 , we had cash and cash equivalents of $ 566.3 million and $ 181.2 million , respectively . we finance our operations primarily through sales to our customers , proceeds from issuance of stock under our stock plans , and proceeds from issuance of debt . we believe that our operations and existing liquidity sources will satisfy our cash requirements for at least the next 12 months . a majority of our customers are billed monthly , and about 63 % of our total billings are collected through credit card payments received at the beginning of each month . as we continue to move up market , the number and size of customers with annual or multi-year contracts and those who opt for annual invoicing is increasing . for these customers , we generally invoice only one annual period in advance and all invoicing occurs at the start of the respective subscription period . revenue is deferred for such advanced billings . as of december 31 , 2018 and 2017 , we had deferred revenue of $ 88.5 million and $ 62.9 million , respectively . as of december 31 , 2018 , the carrying value of our notes was $ 366.6 million . we had no outstanding debt as of december 31 , 2017. our future capital requirements will depend on many factors , including revenue growth and costs incurred to support customer growth , acquisitions and expansions , research and development , litigation , increased general and administrative expenses to support the anticipated growth in our operations , and capital equipment required to support our growing headcount and in support of our co-location data center facilities . our capital expenditures in future periods are expected to grow in line with our business . to the extent that existing cash and cash equivalents are not sufficient to fund our future operations , we may need to raise additional funds through public or private equity offerings or through additional debt financing . we may in the future make investments in or acquisitions of businesses or technologies , which could also require us to seek additional equity or debt financing . additional financing sources may not be available on terms favorable to us or at all . the table below , for the periods indicated , provides selected cash flow information ( in thousands ) : replace_table_token_10_th 55 story_separator_special_tag style= `` font-size:10pt ; font-family : times new roman ; font-weight : normal ; font-style : normal ; text-transform : none ; font-variant : normal ; `` > repurchase s of class a common stock of $ 15.0 million . backlog we have generally signed new customers to contracts that vary in length , from month-to-month to multi-year terms for our subscriptions . the timing of invoicing to our customers is a negotiated term and thus varies among our subscription contracts . payment terms are generally billed either monthly or on an annual basis . at any point in the contract term , there can be amounts that we have not yet been contractually able to invoice , which constitute backlog . until such time as these amounts are invoiced , we do not recognize them as revenues , unearned revenues or elsewhere in our consolidated financial statements . given the variability in our contract length , we believe that backlog is not a reliable indicator of future revenues and we

net cash provided by operating activities cash provided by operating activities is influenced by the amount of cash we invest in personnel , marketing , and infrastructure costs to support the anticipated growth of our business , the increase in the number of customers , the amount and timing of customer collections , as well as the amount and timing of disbursements to our vendors . net cash provided by operating activities was $ 72.1 million for the year ended december 31 , 2018. this was driven by net loss of $ 26.2 million adjusted for impacts of non-cash adjustments of $ 131.4 million . the non-cash adjustments resulted primarily due to $ 68.1 million of stock-based compensation , $ 23.3 million of depreciation and amortization , $ 19.8 million amortization of deferred sales commissions costs , and $ 15.9 million amortization of debt discount and issuance costs related to convertible notes . this was offset by a reduction of net working capital of $ 33.1 million driven primarily by timing of cash payments to vendors and cash receipts and prepayments from customers and carriers . net cash provided by operating activities was $ 41.2 million for the year ended december 31 , 2017. this was driven by net loss of $ 4.2 million adjusted for the impacts of non-cash adjustments of $ 72.0 million . the non-cash adjustments resulted primarily due to $ 42.1 million of stock-based compensation , $ 16.2 million of depreciation and amortization , and $ 12.6 million amortization of deferred sales commissions costs . this was partially offset by net working capital changes of $ 26.7 million , which was primarily driven by timing of cash receipts and prepayments from our customers and carriers and payments to vendors .


 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 cash provided by operating activities is influenced by the amount of cash we invest in personnel , marketing , and infrastructure costs to support the anticipated growth of our business , the increase in the number of customers , the amount and timing of customer collections , as well as the amount and timing of disbursements to our vendors . net cash provided by operating activities was $ 72.1 million for the year ended december 31 , 2018. this was driven by net loss of $ 26.2 million adjusted for impacts of non-cash adjustments of $ 131.4 million . the non-cash adjustments resulted primarily due to $ 68.1 million of stock-based compensation , $ 23.3 million of depreciation and amortization , $ 19.8 million amortization of deferred sales commissions costs , and $ 15.9 million amortization of debt discount and issuance costs related to convertible notes . this was offset by a reduction of net working capital of $ 33.1 million driven primarily by timing of cash payments to vendors and cash receipts and prepayments from customers and carriers . net cash provided by operating activities was $ 41.2 million for the year ended december 31 , 2017. this was driven by net loss of $ 4.2 million adjusted for the impacts of non-cash adjustments of $ 72.0 million . the non-cash adjustments resulted primarily due to $ 42.1 million of stock-based compensation , $ 16.2 million of depreciation and amortization , and $ 12.6 million amortization of deferred sales commissions costs . this was partially offset by net working capital changes of $ 26.7 million , which was primarily driven by timing of cash receipts and prepayments from our customers and carriers and payments to vendors .
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 Suspicious Activity Report : for the years ended december 31 , 2018 , 2017 and 2016 , the vast majority of our total revenues were generated in the u.s. and canada , although we expect the percentage of our total revenues derived outside of the u.s. and canada to grow as we continue to expand internationally . the growth of our business and our future success depend on many factors , including our ability to expand our customer base to medium-sized and larger customers , continue to innovate , grow revenues from our existing customer base , expand our distribution channels , and scale internationally . while these areas represent significant opportunities for us , they also pose risks and challenges that we must address in order to sustain the growth of our business and improve our operating results . we have experienced significant growth in recent periods , with total revenues of $ 673.6 million , $ 503.6 million and $ 380.4 million , in the years ended december 31 , 2018 , 2017 and 2016 , respectively , representing year-over-year increases of 34 % and 32 % , respectively . we have continued to make significant expenditures and investments , including those in sales and marketing , research and development , infrastructure and operations and incurred net losses of $ 26.2 million , $ 4.2 million , and $ 16.2 million in the years ended december 31 , 2018 , 2017 and 2016 , respectively . 47 key business metrics in addition to united states generally accepted accounting principles ( “ u.s . gaap ” ) and financial measures such as total revenues , gross margin , and cash flows from operations , we regularly review a number of key business metrics to evaluate growth trends , measure our performance , and make strategic decisions . we discuss revenues and gross margin under “ results of operations ” and cash flow from operations under “ liquidity and capital resources . ” other key business metrics are discussed below . annualized exit monthly recurring subscriptions we believe that our annualized exit monthly recurring subscriptions ( “ arr ” ) is a leading indicator of our anticipated subscriptions revenues . we believe that trends in revenue are important to understanding the overall health of our business , and we use these trends in order to formulate financial projections and make strategic business decisions . our arr equals our monthly recurring subscriptions multiplied by 12. our monthly recurring subscriptions equals the monthly value of all customer recurring charges contracted at the end of a given month . for example , our monthly recurring subscriptions at december 31 , 2018 were $ 60.5 million . as such , our arr at december 31 , 2018 was $ 725.8 million compared to $ 546.4 million at december 31 , 2017. ringcentral office annualized exit monthly recurring subscriptions we calculate our ringcentral office annualized exit monthly recurring subscriptions ( “ office arr ” ) in the same manner as we calculate our arr , except that only customer subscriptions from ringcentral office , ringcentral contact center , and ringcentral engage customers are included when determining monthly recurring subscriptions for the purposes of calculating this key business metric . we believe that trends in revenue with respect to these products are important to the understanding of the overall health of our business , and we use these trends in order to formulate financial projections and make strategic business decisions . our office arr at december 31 , 2018 was $ 644.1 million compared to $ 466.2 million at december 31 , 2017. net monthly subscription dollar retention rate we believe that our net monthly subscription dollar retention rate provides insight into our ability to retain and grow software subscriptions revenue , as well as our customers ' potential long-term value to us . we believe that our ability to retain our customers and expand their use of our solutions over time is a leading indicator of the stability of our revenue base and we use these trends in order to formulate financial projections and make strategic business decisions . we define our net monthly subscription dollar retention rate as ( i ) one plus ( ii ) the quotient of dollar net change divided by average dollar monthly recurring subscriptions . we define dollar net change as the quotient of ( i ) the difference of our monthly recurring subscriptions at the end of a period minus our monthly recurring subscriptions at the beginning of a period minus our monthly recurring subscriptions at the end of the period from new customers , we added during the period , ( ii ) all divided by the number of months in the period . we define our average monthly recurring subscriptions as the average of the monthly recurring subscriptions at the beginning and end of the measurement period . for example , if our monthly recurring subscriptions were $ 118 at the end of a quarterly period and $ 100 at the beginning of period , and $ 20 at the end of the period from new customers we added during the period , then the dollar net change would be equal to ( $ 0.67 ) , or the amount equal to the difference of $ 118 minus $ 100 minus $ 20 , all divided by three months . our average monthly recurring subscriptions would equal $ 109 , or the sum of $ 100 plus $ 118 , divided by two . our net monthly subscription dollar retention rate would then equal 99.4 % , or approximately 99 % , or one plus the quotient of the dollar net change divided by the average monthly recurring subscriptions . story_separator_special_tag the increase in personnel costs was primarily due headcount of growth and higher share-based compensation expense of $ 5.1 million . the increases in sales and marketing headcount and other expense categories were necessary to support our growth strategy to acquire new customers with a focus on larger customers and establish brand recognition to achieve greater penetration in the north american and international markets . additionally , we expect sales and marketing expenses to continue to increase in absolute dollars as we continue to expand our presence in north america , europe , and other markets . general and administrative replace_table_token_8_th general and administrative expenses increased by $ 30.5 million , or 42 % , from fiscal year 2017 to 2018 primarily due to increases in personnel costs of $ 21.6 million , legal and professional fees of $ 4.8 million and acquisition related costs of $ 2.5 million . the increase in personnel costs was primarily driven by headcount growth and higher share-based compensation expense of $ 8.0 million . general and administrative expenses increased by $ 16.9 million , or 30 % , from fiscal year 2016 to 2017 primarily due to increases in personnel costs of $ 13.1 million , travel and overhead costs of $ 1.5 million , and professional fees of $ 1.4 million . the increase in personnel costs was primarily driven by headcount growth and higher share-based compensation expense of $ 3.3 million . we expect general and administrative expenses to continue to increase in absolute dollars as we continue to make additional investments in processes , systems , and personnel to support our anticipated revenue growth . 54 other income ( e xpense ) , net replace_table_token_9_th other expense , net increased by $ 11.0 million from fiscal year 2017 to 2018 , primarily due to a $ 16.0 million increase in interest expense resulting from the amortization of debt discount and issuance costs of our 0 % convertible senior notes due 2023 ( “ notes ” ) , and foreign currency losses of $ 1.9 million . this was partially offset by a $ 6.8 million increase in interest income on our cash and cash equivalents . other income , net increased by $ 4.5 million from fiscal year 2016 to 2017 primarily due to foreign currency gains driven by the significant increase in the canadian dollar relative to the u.s. dollar and lower interest expense of $ 0.6 million due to the repayment of our debt in february 2017. liquidity and capital resources as of december 31 , 2018 and 2017 , we had cash and cash equivalents of $ 566.3 million and $ 181.2 million , respectively . we finance our operations primarily through sales to our customers , proceeds from issuance of stock under our stock plans , and proceeds from issuance of debt . we believe that our operations and existing liquidity sources will satisfy our cash requirements for at least the next 12 months . a majority of our customers are billed monthly , and about 63 % of our total billings are collected through credit card payments received at the beginning of each month . as we continue to move up market , the number and size of customers with annual or multi-year contracts and those who opt for annual invoicing is increasing . for these customers , we generally invoice only one annual period in advance and all invoicing occurs at the start of the respective subscription period . revenue is deferred for such advanced billings . as of december 31 , 2018 and 2017 , we had deferred revenue of $ 88.5 million and $ 62.9 million , respectively . as of december 31 , 2018 , the carrying value of our notes was $ 366.6 million . we had no outstanding debt as of december 31 , 2017. our future capital requirements will depend on many factors , including revenue growth and costs incurred to support customer growth , acquisitions and expansions , research and development , litigation , increased general and administrative expenses to support the anticipated growth in our operations , and capital equipment required to support our growing headcount and in support of our co-location data center facilities . our capital expenditures in future periods are expected to grow in line with our business . to the extent that existing cash and cash equivalents are not sufficient to fund our future operations , we may need to raise additional funds through public or private equity offerings or through additional debt financing . we may in the future make investments in or acquisitions of businesses or technologies , which could also require us to seek additional equity or debt financing . additional financing sources may not be available on terms favorable to us or at all . the table below , for the periods indicated , provides selected cash flow information ( in thousands ) : replace_table_token_10_th 55 story_separator_special_tag style= `` font-size:10pt ; font-family : times new roman ; font-weight : normal ; font-style : normal ; text-transform : none ; font-variant : normal ; `` > repurchase s of class a common stock of $ 15.0 million . backlog we have generally signed new customers to contracts that vary in length , from month-to-month to multi-year terms for our subscriptions . the timing of invoicing to our customers is a negotiated term and thus varies among our subscription contracts . payment terms are generally billed either monthly or on an annual basis . at any point in the contract term , there can be amounts that we have not yet been contractually able to invoice , which constitute backlog . until such time as these amounts are invoiced , we do not recognize them as revenues , unearned revenues or elsewhere in our consolidated financial statements . given the variability in our contract length , we believe that backlog is not a reliable indicator of future revenues and we

