physicians have already used mridian to treat a broad spectrum of radiation therapy patients with more than 45 different types of cancer , as well as patients for whom radiation therapy was previously not an option . at december 31 , 2019 , we had five mridian with cobalt-60 systems and 30 mridian linac systems installed at 33 cancer centers worldwide ( 14 in the united states and 19 outside the united states ) . in addition , six mridian linacs have been delivered to customers that are in varying stages of installation . we currently market mridian through a direct sales force in north america . in the rest of the world , we market mridian through a hybrid model of both a direct sales force and distribution network . we market mridian to a broad range of worldwide customers , including university research and teaching hospitals , community hospitals , private practices , government institutions and freestanding cancer centers . as with the traditional linac market , our sales and revenue cycles vary based on the particular customer and can be lengthy , sometimes lasting up to 18 to 24 months ( or more ) from initial customer contact to order contract execution . following execution of an order contract , it generally takes nine to 15 months for a customer to customize an existing facility or construct a new vault . upon the commencement of installation at a customer 's facility , it typically takes approximately 50 to 90 days for us to install mridian and perform on-site testing of the system , including the completion of acceptance test procedures . we generated product , service and distribution rights revenues of $ 87.8 million , $ 81.0 million and $ 34.0 million , and had net losses of $ 120.2 million , $ 76.4 million and $ 72.2 million during the years ended december 31 , 2019 , 2018 and 2017 , respectively . 58 we expect to continue to incur significant expenses and operating losses for the foreseeable future . we expect our expenses will increase substantially in connection with our ongoing activities , as we : add personnel to support our product development and commercialization efforts ; continue our research and development efforts ; seek regulatory approval for mridian in certain foreign countries ; and operate as a public company . accordingly , we may seek to fund our operations through public or private equity , debt financings or other sources . however , we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all . our failure to raise capital or enter into such other arrangements as and when needed would have a negative impact on our financial condition and our ability to develop enhancements to and integrate new technologies into mr image-guided radiation therapy systems . december 2019 public offering of common stock on december 3 , 2019 , we entered into an underwriting agreement with piper jaffray & co. , as representatives of several underwriters , or the december 2019 underwriters , in connection with the issuance and sale of 41,550,000 shares of our common stock at a public offering price of $ 3.13 per share , or the december 2019 public offering of common stock . in addition , we granted the december 2019 underwriters a 30-day option to purchase up to 6,232,500 additional shares of common stock on the same terms , which the december 2019 underwriters exercised in full . we completed the offering on december 6 , 2019 and received aggregate net proceeds of approximately $ 138.4 million , after deducting underwriting discounts and commissions and offering expenses payable by us . august 2018 public offering of common stock on august 14 , 2018 , we entered into an underwriting agreement with morgan stanley & co. llc and jefferies llc , as representatives of several underwriters , or the august 2018 underwriters , in connection with the issuance and sale of 16,216,217 shares of our common stock at a public offering price of $ 9.25 per share , or the august 2018 public offering of common stock . in addition , we granted the august 2018 underwriters a 30-day option to purchase up to 2,432,432 additional shares of common stock on the same terms , which the august 2018 underwriters exercised in full . we completed the offering on august 17 , 2018 and received aggregate net proceeds of approximately $ 161.9 million , after deducting underwriting discounts and commissions and offering expenses payable by us . march 2018 direct registered offering in february 2018 , we entered into a securities purchase agreement pursuant to which we sold ( i ) 4,090,000 shares of our common stock ; ( ii ) 3,000,581 shares of our series a convertible preferred stock and ( iii ) warrants to purchase 1,418,116 shares of our common stock , or the 2018 offering warrants , for total gross proceeds of $ 59.1 million , or the march 2018 direct registered offering . we completed the march 2018 direct registered offering on march 5 , 2018. the 2018 offering warrants have an exercise price of $ 8.31 per share , became exercisable upon issuance and expire in march 2025. all outstanding shares of series a convertible preferred stock were converted into common stock at a conversion ratio of 1:1 on april 19 , 2018. october 2017 direct registered offering in october 2017 , we entered into securities purchase agreements pursuant to which we sold an aggregate of 8,382,643 shares of common stock for total gross proceeds of $ 49.9 million , or the october 2017 direct registered offering . we completed the closing of the october 2017 direct registered offering on october 25 , 2017 . story_separator_special_tag other income ( expense ) , net other income ( expense ) , net consists primarily of changes in the fair value of the 2017 and 2016 placement warrants and foreign currency exchange gains and losses . the outstanding 2017 and 2016 placement warrants are re-measured to fair value at each balance sheet date with the corresponding gain or loss from the adjustment recorded as a component of other income ( expense ) , net . 62 results of operation s the following tables set forth our results of operations for the periods presented ( in thousands ) : replace_table_token_5_th comparison of the years ended december 31 , 2019 and 2018 revenue replace_table_token_6_th total revenue during the year ended december 31 , 2019 increased by $ 6.8 million or 8.4 % compared to the year ended december 31 , 2018. the increase was primarily due to the increased average selling price from the revenue recognized on mridian systems and two system upgrades during the year ended december 31 , 2019 , compared to revenue recognized on mridian systems and two system upgrades during the year ended december 31 , 2018 , revenue recognized from performance obligations satisfied in the prior year , and growth in our installed base driving the increase in service revenues . product revenue . product revenue increased by $ 2.9 million , or 3.8 % , in fiscal year 2019 compared to fiscal year 2018. the increase is primarily due to the increased average selling price on mridian systems and system upgrades in fiscal year 2019 compared to the revenue recognized from the sale of mridian systems and systems upgrades in fiscal year 2018 and $ 0.9 million of revenue recognized from performance obligations satisfied in the prior year . service revenue . service revenue increased by $ 3.9 million , or 102.1 % , in fiscal year 2019 compared to fiscal year 2018 due to increased billings to existing customers , as well as the growth in our installed base . distribution rights revenue . after receipt of japanese regulatory approval in august 2016 , we started recognizing the distribution rights revenue ratably over the remaining term of the distribution agreement with itochu . distribution rights revenue remained flat in fiscal year 2019 compared to fiscal year 2018 due to the ratable recognition of revenue over the term of the agreement . 63 cost of revenue replace_table_token_7_th product cost of revenue . product cost of revenue increased by $ 13.9 million , or 20.9 % , in fiscal year 2019 compared to fiscal year 2018. the total cost of revenue in fiscal year 2019 was impacted by approximately $ 9.3 million of charges , primarily driven by higher than anticipated installation costs related to historical upgrade commitments , and a $ 5.7 million increase in costs of materials , partially offset by a $ 1.2 million inventory valuation adjustment recognized in fiscal year 2018. the $ 9.3 million includes $ 7.9 million of one-time charges and $ 1.4 million of expenses . service cost of revenue . service cost of revenue increased by $ 5.0 million , or 63.5 % , in fiscal year 2019 compared to fiscal year 2018. the increase in service cost of revenue was primarily due to the larger installed base in fiscal year 2019 and service personnel being fully utilized for service purposes during the year . operating expenses replace_table_token_8_th research and development . research and development expenses increased by $ 7.3 million , or 44.0 % , in fiscal year 2019 compared to fiscal year 2018 . this increase was primarily attributable to a $ 5.4 million increase in personnel expense due to higher average headcount , a $ 1.3 million increase in facilities expenses and a $ 0.4 million increase in depreciation expense . selling and marketing . selling and marketing expenses increased by $ 10.7 million , or 71.3 % , in fiscal year 2019 compared to fiscal year 2018. this increase was primarily attributable to a $ 9.3 million increase in personnel expense due to higher average headcount in fiscal 2019 and a $ 1.5 million increase in travel expense . general and administrative . general and administrative expenses increased by $ 15.6 million , or 31.1 % , in fiscal year 2019 compared to fiscal year 2018. this increase was primarily attributable to a $ 9.5 million increase in personnel expense due to higher average headcount , which includes a $ 4.5 million increase in stock-based compensation expense for the increased headcount and executives hired since the second quarter of 2018 , a $ 4.3 million increase in consulting and other professional services and a $ 1.6 million increase in office expenses , which includes property taxes and software licenses . interest income year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) interest income $ 1,721 $ 8 $ 1,713 21412.5 % interest income increased by $ 1.7 million in fiscal year 2019 compared to fiscal year 2018 primarily due to an increase in invested funds during 2019. interest expense year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) interest expense $ ( 4,327 ) $ ( 7,701 ) $ 3,374 -43.8 % interest expense decreased by $ 3.4 million in fiscal year 2019 compared to fiscal year 2018 , mainly due to the lower interest rate of the svb term loan as compared to the crg term loan , which was paid off in december 2018 . 64 other income ( expense ) , net year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) other income ( expense ) , net $ 3,202 $ 6,389 $ ( 3,187 ) -49.9 % other income ( expense ) , net for fiscal year 2019 consisted primarily of a $ 2.5 million decrease in the fair value

liquidity and capital resources since our inception in 2004 , we have incurred significant net losses and negative cash flows from operations . during the years ended december 31 , 2019 , 2018 and 2017 , we had a net loss of $ 120.2 million , $ 76.4 million and $ 72.2 million , respectively . at december 31 , 2019 and 2018 , we had an accumulated deficit of $ 519.2 million and $ 399.0 million , respectively . at december 31 , 2019 and 2018 , we had cash and cash equivalents of $ 226.8 million and $ 167.4 million , respectively . to date , we have financed our operations principally through offerings of our capital stock , issuances of warrants , use of term loans and receipts of customer deposits for new orders and payments from customers for systems installed and delivered . we may , from time to time , seek to raise capital through a variety of sources , including the public equity market , private equity financing , and public or private debt . in january 2017 , we issued common stock and warrants to purchase common stock via the 2017 private placement for gross proceeds of $ 26.1 million . in 2017 , we also raised aggregate gross proceeds of $ 40.1 million through our at-the-market offering program under which we sold approximately 6.6 million shares of our common stock at an average sale price of $ 6.10 per share . in october 2017 , we issued common stock in the october 2017 direct registered offering for gross proceeds of $ 49.9 million . in march 2018 , we issued common stock , series a convertible preferred stock and warrants to purchase common stock in the march 2018 direct registered offering for gross proceeds of $ 59.1 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.
     ```liquidity and capital resources since our inception in 2004 , we have incurred significant net losses and negative cash flows from operations . during the years ended december 31 , 2019 , 2018 and 2017 , we had a net loss of $ 120.2 million , $ 76.4 million and $ 72.2 million , respectively . at december 31 , 2019 and 2018 , we had an accumulated deficit of $ 519.2 million and $ 399.0 million , respectively . at december 31 , 2019 and 2018 , we had cash and cash equivalents of $ 226.8 million and $ 167.4 million , respectively . to date , we have financed our operations principally through offerings of our capital stock , issuances of warrants , use of term loans and receipts of customer deposits for new orders and payments from customers for systems installed and delivered . we may , from time to time , seek to raise capital through a variety of sources , including the public equity market , private equity financing , and public or private debt . in january 2017 , we issued common stock and warrants to purchase common stock via the 2017 private placement for gross proceeds of $ 26.1 million . in 2017 , we also raised aggregate gross proceeds of $ 40.1 million through our at-the-market offering program under which we sold approximately 6.6 million shares of our common stock at an average sale price of $ 6.10 per share . in october 2017 , we issued common stock in the october 2017 direct registered offering for gross proceeds of $ 49.9 million . in march 2018 , we issued common stock , series a convertible preferred stock and warrants to purchase common stock in the march 2018 direct registered offering for gross proceeds of $ 59.1 million .
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 Suspicious Activity Report : physicians have already used mridian to treat a broad spectrum of radiation therapy patients with more than 45 different types of cancer , as well as patients for whom radiation therapy was previously not an option . at december 31 , 2019 , we had five mridian with cobalt-60 systems and 30 mridian linac systems installed at 33 cancer centers worldwide ( 14 in the united states and 19 outside the united states ) . in addition , six mridian linacs have been delivered to customers that are in varying stages of installation . we currently market mridian through a direct sales force in north america . in the rest of the world , we market mridian through a hybrid model of both a direct sales force and distribution network . we market mridian to a broad range of worldwide customers , including university research and teaching hospitals , community hospitals , private practices , government institutions and freestanding cancer centers . as with the traditional linac market , our sales and revenue cycles vary based on the particular customer and can be lengthy , sometimes lasting up to 18 to 24 months ( or more ) from initial customer contact to order contract execution . following execution of an order contract , it generally takes nine to 15 months for a customer to customize an existing facility or construct a new vault . upon the commencement of installation at a customer 's facility , it typically takes approximately 50 to 90 days for us to install mridian and perform on-site testing of the system , including the completion of acceptance test procedures . we generated product , service and distribution rights revenues of $ 87.8 million , $ 81.0 million and $ 34.0 million , and had net losses of $ 120.2 million , $ 76.4 million and $ 72.2 million during the years ended december 31 , 2019 , 2018 and 2017 , respectively . 58 we expect to continue to incur significant expenses and operating losses for the foreseeable future . we expect our expenses will increase substantially in connection with our ongoing activities , as we : add personnel to support our product development and commercialization efforts ; continue our research and development efforts ; seek regulatory approval for mridian in certain foreign countries ; and operate as a public company . accordingly , we may seek to fund our operations through public or private equity , debt financings or other sources . however , we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all . our failure to raise capital or enter into such other arrangements as and when needed would have a negative impact on our financial condition and our ability to develop enhancements to and integrate new technologies into mr image-guided radiation therapy systems . december 2019 public offering of common stock on december 3 , 2019 , we entered into an underwriting agreement with piper jaffray & co. , as representatives of several underwriters , or the december 2019 underwriters , in connection with the issuance and sale of 41,550,000 shares of our common stock at a public offering price of $ 3.13 per share , or the december 2019 public offering of common stock . in addition , we granted the december 2019 underwriters a 30-day option to purchase up to 6,232,500 additional shares of common stock on the same terms , which the december 2019 underwriters exercised in full . we completed the offering on december 6 , 2019 and received aggregate net proceeds of approximately $ 138.4 million , after deducting underwriting discounts and commissions and offering expenses payable by us . august 2018 public offering of common stock on august 14 , 2018 , we entered into an underwriting agreement with morgan stanley & co. llc and jefferies llc , as representatives of several underwriters , or the august 2018 underwriters , in connection with the issuance and sale of 16,216,217 shares of our common stock at a public offering price of $ 9.25 per share , or the august 2018 public offering of common stock . in addition , we granted the august 2018 underwriters a 30-day option to purchase up to 2,432,432 additional shares of common stock on the same terms , which the august 2018 underwriters exercised in full . we completed the offering on august 17 , 2018 and received aggregate net proceeds of approximately $ 161.9 million , after deducting underwriting discounts and commissions and offering expenses payable by us . march 2018 direct registered offering in february 2018 , we entered into a securities purchase agreement pursuant to which we sold ( i ) 4,090,000 shares of our common stock ; ( ii ) 3,000,581 shares of our series a convertible preferred stock and ( iii ) warrants to purchase 1,418,116 shares of our common stock , or the 2018 offering warrants , for total gross proceeds of $ 59.1 million , or the march 2018 direct registered offering . we completed the march 2018 direct registered offering on march 5 , 2018. the 2018 offering warrants have an exercise price of $ 8.31 per share , became exercisable upon issuance and expire in march 2025. all outstanding shares of series a convertible preferred stock were converted into common stock at a conversion ratio of 1:1 on april 19 , 2018. october 2017 direct registered offering in october 2017 , we entered into securities purchase agreements pursuant to which we sold an aggregate of 8,382,643 shares of common stock for total gross proceeds of $ 49.9 million , or the october 2017 direct registered offering . we completed the closing of the october 2017 direct registered offering on october 25 , 2017 . story_separator_special_tag other income ( expense ) , net other income ( expense ) , net consists primarily of changes in the fair value of the 2017 and 2016 placement warrants and foreign currency exchange gains and losses . the outstanding 2017 and 2016 placement warrants are re-measured to fair value at each balance sheet date with the corresponding gain or loss from the adjustment recorded as a component of other income ( expense ) , net . 62 results of operation s the following tables set forth our results of operations for the periods presented ( in thousands ) : replace_table_token_5_th comparison of the years ended december 31 , 2019 and 2018 revenue replace_table_token_6_th total revenue during the year ended december 31 , 2019 increased by $ 6.8 million or 8.4 % compared to the year ended december 31 , 2018. the increase was primarily due to the increased average selling price from the revenue recognized on mridian systems and two system upgrades during the year ended december 31 , 2019 , compared to revenue recognized on mridian systems and two system upgrades during the year ended december 31 , 2018 , revenue recognized from performance obligations satisfied in the prior year , and growth in our installed base driving the increase in service revenues . product revenue . product revenue increased by $ 2.9 million , or 3.8 % , in fiscal year 2019 compared to fiscal year 2018. the increase is primarily due to the increased average selling price on mridian systems and system upgrades in fiscal year 2019 compared to the revenue recognized from the sale of mridian systems and systems upgrades in fiscal year 2018 and $ 0.9 million of revenue recognized from performance obligations satisfied in the prior year . service revenue . service revenue increased by $ 3.9 million , or 102.1 % , in fiscal year 2019 compared to fiscal year 2018 due to increased billings to existing customers , as well as the growth in our installed base . distribution rights revenue . after receipt of japanese regulatory approval in august 2016 , we started recognizing the distribution rights revenue ratably over the remaining term of the distribution agreement with itochu . distribution rights revenue remained flat in fiscal year 2019 compared to fiscal year 2018 due to the ratable recognition of revenue over the term of the agreement . 63 cost of revenue replace_table_token_7_th product cost of revenue . product cost of revenue increased by $ 13.9 million , or 20.9 % , in fiscal year 2019 compared to fiscal year 2018. the total cost of revenue in fiscal year 2019 was impacted by approximately $ 9.3 million of charges , primarily driven by higher than anticipated installation costs related to historical upgrade commitments , and a $ 5.7 million increase in costs of materials , partially offset by a $ 1.2 million inventory valuation adjustment recognized in fiscal year 2018. the $ 9.3 million includes $ 7.9 million of one-time charges and $ 1.4 million of expenses . service cost of revenue . service cost of revenue increased by $ 5.0 million , or 63.5 % , in fiscal year 2019 compared to fiscal year 2018. the increase in service cost of revenue was primarily due to the larger installed base in fiscal year 2019 and service personnel being fully utilized for service purposes during the year . operating expenses replace_table_token_8_th research and development . research and development expenses increased by $ 7.3 million , or 44.0 % , in fiscal year 2019 compared to fiscal year 2018 . this increase was primarily attributable to a $ 5.4 million increase in personnel expense due to higher average headcount , a $ 1.3 million increase in facilities expenses and a $ 0.4 million increase in depreciation expense . selling and marketing . selling and marketing expenses increased by $ 10.7 million , or 71.3 % , in fiscal year 2019 compared to fiscal year 2018. this increase was primarily attributable to a $ 9.3 million increase in personnel expense due to higher average headcount in fiscal 2019 and a $ 1.5 million increase in travel expense . general and administrative . general and administrative expenses increased by $ 15.6 million , or 31.1 % , in fiscal year 2019 compared to fiscal year 2018. this increase was primarily attributable to a $ 9.5 million increase in personnel expense due to higher average headcount , which includes a $ 4.5 million increase in stock-based compensation expense for the increased headcount and executives hired since the second quarter of 2018 , a $ 4.3 million increase in consulting and other professional services and a $ 1.6 million increase in office expenses , which includes property taxes and software licenses . interest income year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) interest income $ 1,721 $ 8 $ 1,713 21412.5 % interest income increased by $ 1.7 million in fiscal year 2019 compared to fiscal year 2018 primarily due to an increase in invested funds during 2019. interest expense year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) interest expense $ ( 4,327 ) $ ( 7,701 ) $ 3,374 -43.8 % interest expense decreased by $ 3.4 million in fiscal year 2019 compared to fiscal year 2018 , mainly due to the lower interest rate of the svb term loan as compared to the crg term loan , which was paid off in december 2018 . 64 other income ( expense ) , net year ended december 31 , 2019 2018 change ( $ ) change ( % ) ( in thousands ) other income ( expense ) , net $ 3,202 $ 6,389 $ ( 3,187 ) -49.9 % other income ( expense ) , net for fiscal year 2019 consisted primarily of a $ 2.5 million decrease in the fair value

