the shockwave process is expected to be operational during the first half of 2019. in addition , we are currently evaluating the implementation of one or more of the following systems or technologies to further lower our use of fossil-based energy sources at the luverne facility : combined heat and power systems ; manure biogas , wind power and certain other expansion and energy reduction technologies . we expect that by approximately the end of 2020 we will have completed certain projects at our luverne facility to improve the carbon intensity score of our products that will increase the value of our ethanol and related products and that should translate into increased revenues for us as a result of the credits associated with our renewable fuels under lcfs and or rfs . we expect this 'de-carbonization ' process will benefit future production expansions at the luverne facility if implemented . as previously disclosed , during 2017 , we hired a third-party engineering firm to test the structural integrity of two of our three carbon steel production fermentation vessels . the results of the testing indicate that one of these fermentation vessels had at least one more year of life before needing repair , and the other one had approximately two months of life remaining . in the middle of 2018 , we hired a third-party engineering firm to test the third carbon steel fermenter . the results indicated the vessel had approximately 1 year of useful life remaining . besides these three carbon steel production fermenters , we have two stainless steel production fermenters . recently , we decided to repair two of the carbon steel fermentation vessels . repairs are expected to be completed by the second quarter of 2019 , at an estimated cost of approximately $ 0.6 million . after the repairs , the estimated useful life of the vessels is expected to be twenty-years . 42 financial condition for the year ended december 31 , 2018 , we incurred a consolidated net loss of $ 28.0 million and had an accumulated deficit of $ 429.3 million . our cash and cash equivalents at december 31 , 2018 totaled $ 33.7 million , which is primarily being used for the following : ( i ) operating activities of our luverne facility ; ( ii ) operating activities at our corporate headquarters in colorado , including research and development work ; ( iii ) capital improvements primarily associated with the luverne facility ; ( iv ) exploration of strategic alternatives and new financings ; and ( v ) debt service obligations . the continued operation of our business is dependent upon raising additional capital through future public and private equity offerings , debt financings or through other alternative financing arrangements . in addition , successful completion of our research and development programs and the attainment of profitable operations are dependent upon future events , including our ability to raise sufficient capital to expand our commercial production facility , completion of our development activities resulting in sales of isobutanol or isobutanol-derived products and or technology , achieving market acceptance and demand for our products and services and attracting and retaining qualified personnel . we expect to incur future net losses as we continue to fund the development and commercialization of our products and product candidates . we have primarily relied on raising capital to fund our operations and debt service obligations by issuing common stock and warrants in underwritten public offerings . those issuances have caused significant dilution to our existing stockholders . while we have sought , and will continue to seek , other , less dilutive forms financing to fund our operations and debt service obligations , there is no assurance that we will be successful in doing so . our transition to profitability is dependent upon , among other things , the successful development and commercialization of our products and product candidates , the achievement of a level of revenues adequate to support our cost structure and securing sufficient financing for the expansion of the luverne facility or a facility at another suitable location . we may never achieve profitability or generate positive cash flows , and unless and until we do , we will continue to need to raise additional cash . we intend to fund future operations through additional private and or public offerings of debt or equity securities . in addition , we may seek additional capital through arrangements with strategic partners or from other sources , may seek to restructure our debt and we will continue to address our cost structure . notwithstanding , there can be no assurance that we will be able to raise additional funds , or achieve or sustain profitability or positive cash flows from operations . 43 results of operations comparison of the years ended december 31 , 201 8 and 201 7 replace_table_token_0_th revenue . during the year ended december 31 , 2018 , we recognized revenue of $ 31.6 million associated with the sale of 19.4 million gallons of ethanol , as well as isobutanol and related products , an increase of $ 5.4 million from the year ended december 31 , 2017 , primarily related to increased production and sales of ethanol at the luverne facility . hydrocarbon revenue increased $ 0.2 million during the year ended december 31 , 2018 primarily as a result of greater shipments of finished products from our demonstration plant located at the south hampton facility . hydrocarbon revenues are comprised of atj , isooctane and isooctene sales . grant and other revenue was $ 25,000 during the year ended december 31 , 2018 , down $ 0.2 million compared to the same period in 2017 , primarily as a result of the company 's contract with the nara ending in 2017. cost of goods sold . story_separator_special_tag holder 's warrants as determined in accordance with an appropriate valuation model and the terms of the respective warrant agreement . based on these terms , we determined that all warrants issued since 2013 ( the “ warrants ” ) qualify as derivatives and , as such , are presented as a derivative warrant liability on the consolidated balance sheets and recorded at fair value each reporting period . the fair value of the warrants was estimated to be $ 22,000 and $ 2.0 million as of december 31 , 2018 and december 31 , 2017 , respectively . the decrease in the estimated fair value of the warrants outstanding as of december 31 , 2018 represents an unrealized gain which has been recorded as a gain from the change in fair value of derivative warrant liability in the consolidated statements of operations . during the year ended december 31 , 2018 , common stock was issued as a result of exercise of warrants as described below : twelve months ended december 31 , 201 8 common stock issued proceeds series a warrants 251 $ 1,054 series k warrants 300,660 1,262,712 300,911 $ 1,263,766 impairment of property , plant and equipment our property , plant and equipment consist primarily of assets associated with the acquisition and retrofit of the luverne facility . we assess impairment of property , plant and equipment for recoverability when events or changes in circumstances indicate that their carrying amount may not be recoverable . circumstances applicable to our current stage of operations which could trigger a review include , but are not limited to : ( i ) significant decreases in the market price of the asset ; ( ii ) significant adverse changes in the business climate or legal or regulatory factors ; ( iii ) accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of the asset ; and ( iv ) expectations that the asset will more likely than not be sold or disposed of significantly before the end of its estimated useful life . the carrying amount of a long-lived asset is considered to be impaired if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset . 51 we evaluated our long-lived assets for impairment as of december 31 , 2018. this evaluation included comparing the carrying amount our long-lived assets to the undiscounted future cash flows of our consolidated net assets as this represents the lowest level of identifiable cash flows . significant assumptions included in the estimated undiscounted future cash flows include , among others , estimates of the : ● sales price of isobutanol , hydrocarbons , ethanol and by-products such as dried distiller 's grains ; ● purchase price of corn ; ● production levels of isobutanol ; ● capital and operating costs to produce isobutanol ; and ● estimated useful life of the primary asset . factors which can impact these assumptions include , but are not limited to ; ● effectiveness of our technology to produce isobutanol at targeted margins ; ● demand for isobutanol , hydrocarbon and oil prices ; and ● harvest levels of corn . based upon our evaluation at december 31 , 2018 , we concluded that the estimated undiscounted future cash flows from luverne exceeded the carrying value of the luverne facility and , as such , these assets were not impaired . although our cash flow forecasts are based on assumptions that are consistent with our planned use of the assets , these estimates required significant exercise of judgment and are subject to change in future reporting periods as facts and circumstances change . additionally , we may make changes to our business plan that could result in changes to the expected cash flows . as a result , it is possible that a long- lived asset may be impaired in future reporting periods . stock-based compensation our stock-based compensation expense includes expenses associated with share-based awards granted to employees and board members and expenses associated with our employee stock purchase plan ( “ espp ” ) . the estimated fair value of stock options and espp awards is determined on the date of grant and recorded to expense over the requisite service period , generally the vesting period . we estimate the fair value of stock option awards using the black-scholes option-pricing model which requires judgments to be made , including estimating : ( i ) the expected life of an award ; ( ii ) stock price volatility ; and ( iii ) prior to our initial public offering in february 2011 , the fair value of our common stock . the black-scholes option-pricing model calculates the estimated fair value of stock options using the following inputs : ( i ) expected stock option life ; ( ii ) expected volatility ; ( iii ) risk-free interest rate ; ( iv ) expected dividend yield rate ; ( v ) exercise price ; and ( vi ) closing price of our common stock on the date of grant . due to our limited history of grant activity , we use the “ simplified method ” permitted by the sec to estimate the expected stock option life as the arithmetic average of the total contractual term of the option and its vesting period . we calculate the estimated volatility rate based on selected comparable public companies , due to a lack of historical information regarding the volatility of our stock price . we will continue to analyze the historical stock price volatility assumption as more historical data for our common stock becomes available . the risk-free interest rate assumption is based on the u.s. treasury yield curve in effect on the date of grant for instruments with a term similar to the expected life of the related option . no dividends are expected to be paid . the estimated

debt , to our consolidated financial statements included herein for further discussion of the 2020 notes . 48 2022 notes in july 2012 , we issued and sold $ 45.0 million in aggregate principal amount of 2022 notes , for net proceeds of $ 40.9 million , after accounting for $ 2.7 million and $ 1.4 million of cash discounts and issue costs , respectively . the 2022 notes bore interest at 7.5 % which was to be paid semi-annually in arrears on january 1 and july 1 of each year commencing on january 1 , 2013. in the first quarter of 2018 , we issued an aggregate of 780,303 shares of our common stock in exchange for the redemption of the then remaining $ 515,000 in outstanding 2022 notes . as a result of this exchange , all obligations under the 2022 notes have been fully satisfied . at-the-market offering program . in february 2018 , we commenced an at-the-market offering program , which initially allowed us to sell and issue up to $ 5.0 million of shares of our common stock . the at-the-market offering program was amended multiple times in june 2018 to increase the available capacity under the at-the-market offering program by an aggregate of approximately $ 84.9 million . as of december 31 , 2018 , we have remaining capacity to issue and sell up to approximately $ 44.6 million of additional shares of common stock under the at-the-market offering program . during the year ended december 31 , 2018 , we issued 6,936,930 shares of common stock ( after giving effect to the reverse stock split under the at-the-market offering program for gross proceeds of $ 40.3 million . we paid commissions to our sales agent of approximately $ 0.9 million and incurred other offering related expenses of $ 0.4 million during the year ended december 31 , 2018. during the three months ended december 31 , 2018 , we issued 545,313 shares of common stock under the at-the-market offering program for gross proceeds of $ 2.5 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.
     ```debt , to our consolidated financial statements included herein for further discussion of the 2020 notes . 48 2022 notes in july 2012 , we issued and sold $ 45.0 million in aggregate principal amount of 2022 notes , for net proceeds of $ 40.9 million , after accounting for $ 2.7 million and $ 1.4 million of cash discounts and issue costs , respectively . the 2022 notes bore interest at 7.5 % which was to be paid semi-annually in arrears on january 1 and july 1 of each year commencing on january 1 , 2013. in the first quarter of 2018 , we issued an aggregate of 780,303 shares of our common stock in exchange for the redemption of the then remaining $ 515,000 in outstanding 2022 notes . as a result of this exchange , all obligations under the 2022 notes have been fully satisfied . at-the-market offering program . in february 2018 , we commenced an at-the-market offering program , which initially allowed us to sell and issue up to $ 5.0 million of shares of our common stock . the at-the-market offering program was amended multiple times in june 2018 to increase the available capacity under the at-the-market offering program by an aggregate of approximately $ 84.9 million . as of december 31 , 2018 , we have remaining capacity to issue and sell up to approximately $ 44.6 million of additional shares of common stock under the at-the-market offering program . during the year ended december 31 , 2018 , we issued 6,936,930 shares of common stock ( after giving effect to the reverse stock split under the at-the-market offering program for gross proceeds of $ 40.3 million . we paid commissions to our sales agent of approximately $ 0.9 million and incurred other offering related expenses of $ 0.4 million during the year ended december 31 , 2018. during the three months ended december 31 , 2018 , we issued 545,313 shares of common stock under the at-the-market offering program for gross proceeds of $ 2.5 million .
```    
 Suspicious Activity Report : the shockwave process is expected to be operational during the first half of 2019. in addition , we are currently evaluating the implementation of one or more of the following systems or technologies to further lower our use of fossil-based energy sources at the luverne facility : combined heat and power systems ; manure biogas , wind power and certain other expansion and energy reduction technologies . we expect that by approximately the end of 2020 we will have completed certain projects at our luverne facility to improve the carbon intensity score of our products that will increase the value of our ethanol and related products and that should translate into increased revenues for us as a result of the credits associated with our renewable fuels under lcfs and or rfs . we expect this 'de-carbonization ' process will benefit future production expansions at the luverne facility if implemented . as previously disclosed , during 2017 , we hired a third-party engineering firm to test the structural integrity of two of our three carbon steel production fermentation vessels . the results of the testing indicate that one of these fermentation vessels had at least one more year of life before needing repair , and the other one had approximately two months of life remaining . in the middle of 2018 , we hired a third-party engineering firm to test the third carbon steel fermenter . the results indicated the vessel had approximately 1 year of useful life remaining . besides these three carbon steel production fermenters , we have two stainless steel production fermenters . recently , we decided to repair two of the carbon steel fermentation vessels . repairs are expected to be completed by the second quarter of 2019 , at an estimated cost of approximately $ 0.6 million . after the repairs , the estimated useful life of the vessels is expected to be twenty-years . 42 financial condition for the year ended december 31 , 2018 , we incurred a consolidated net loss of $ 28.0 million and had an accumulated deficit of $ 429.3 million . our cash and cash equivalents at december 31 , 2018 totaled $ 33.7 million , which is primarily being used for the following : ( i ) operating activities of our luverne facility ; ( ii ) operating activities at our corporate headquarters in colorado , including research and development work ; ( iii ) capital improvements primarily associated with the luverne facility ; ( iv ) exploration of strategic alternatives and new financings ; and ( v ) debt service obligations . the continued operation of our business is dependent upon raising additional capital through future public and private equity offerings , debt financings or through other alternative financing arrangements . in addition , successful completion of our research and development programs and the attainment of profitable operations are dependent upon future events , including our ability to raise sufficient capital to expand our commercial production facility , completion of our development activities resulting in sales of isobutanol or isobutanol-derived products and or technology , achieving market acceptance and demand for our products and services and attracting and retaining qualified personnel . we expect to incur future net losses as we continue to fund the development and commercialization of our products and product candidates . we have primarily relied on raising capital to fund our operations and debt service obligations by issuing common stock and warrants in underwritten public offerings . those issuances have caused significant dilution to our existing stockholders . while we have sought , and will continue to seek , other , less dilutive forms financing to fund our operations and debt service obligations , there is no assurance that we will be successful in doing so . our transition to profitability is dependent upon , among other things , the successful development and commercialization of our products and product candidates , the achievement of a level of revenues adequate to support our cost structure and securing sufficient financing for the expansion of the luverne facility or a facility at another suitable location . we may never achieve profitability or generate positive cash flows , and unless and until we do , we will continue to need to raise additional cash . we intend to fund future operations through additional private and or public offerings of debt or equity securities . in addition , we may seek additional capital through arrangements with strategic partners or from other sources , may seek to restructure our debt and we will continue to address our cost structure . notwithstanding , there can be no assurance that we will be able to raise additional funds , or achieve or sustain profitability or positive cash flows from operations . 43 results of operations comparison of the years ended december 31 , 201 8 and 201 7 replace_table_token_0_th revenue . during the year ended december 31 , 2018 , we recognized revenue of $ 31.6 million associated with the sale of 19.4 million gallons of ethanol , as well as isobutanol and related products , an increase of $ 5.4 million from the year ended december 31 , 2017 , primarily related to increased production and sales of ethanol at the luverne facility . hydrocarbon revenue increased $ 0.2 million during the year ended december 31 , 2018 primarily as a result of greater shipments of finished products from our demonstration plant located at the south hampton facility . hydrocarbon revenues are comprised of atj , isooctane and isooctene sales . grant and other revenue was $ 25,000 during the year ended december 31 , 2018 , down $ 0.2 million compared to the same period in 2017 , primarily as a result of the company 's contract with the nara ending in 2017. cost of goods sold . story_separator_special_tag holder 's warrants as determined in accordance with an appropriate valuation model and the terms of the respective warrant agreement . based on these terms , we determined that all warrants issued since 2013 ( the “ warrants ” ) qualify as derivatives and , as such , are presented as a derivative warrant liability on the consolidated balance sheets and recorded at fair value each reporting period . the fair value of the warrants was estimated to be $ 22,000 and $ 2.0 million as of december 31 , 2018 and december 31 , 2017 , respectively . the decrease in the estimated fair value of the warrants outstanding as of december 31 , 2018 represents an unrealized gain which has been recorded as a gain from the change in fair value of derivative warrant liability in the consolidated statements of operations . during the year ended december 31 , 2018 , common stock was issued as a result of exercise of warrants as described below : twelve months ended december 31 , 201 8 common stock issued proceeds series a warrants 251 $ 1,054 series k warrants 300,660 1,262,712 300,911 $ 1,263,766 impairment of property , plant and equipment our property , plant and equipment consist primarily of assets associated with the acquisition and retrofit of the luverne facility . we assess impairment of property , plant and equipment for recoverability when events or changes in circumstances indicate that their carrying amount may not be recoverable . circumstances applicable to our current stage of operations which could trigger a review include , but are not limited to : ( i ) significant decreases in the market price of the asset ; ( ii ) significant adverse changes in the business climate or legal or regulatory factors ; ( iii ) accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of the asset ; and ( iv ) expectations that the asset will more likely than not be sold or disposed of significantly before the end of its estimated useful life . the carrying amount of a long-lived asset is considered to be impaired if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset . 51 we evaluated our long-lived assets for impairment as of december 31 , 2018. this evaluation included comparing the carrying amount our long-lived assets to the undiscounted future cash flows of our consolidated net assets as this represents the lowest level of identifiable cash flows . significant assumptions included in the estimated undiscounted future cash flows include , among others , estimates of the : ● sales price of isobutanol , hydrocarbons , ethanol and by-products such as dried distiller 's grains ; ● purchase price of corn ; ● production levels of isobutanol ; ● capital and operating costs to produce isobutanol ; and ● estimated useful life of the primary asset . factors which can impact these assumptions include , but are not limited to ; ● effectiveness of our technology to produce isobutanol at targeted margins ; ● demand for isobutanol , hydrocarbon and oil prices ; and ● harvest levels of corn . based upon our evaluation at december 31 , 2018 , we concluded that the estimated undiscounted future cash flows from luverne exceeded the carrying value of the luverne facility and , as such , these assets were not impaired . although our cash flow forecasts are based on assumptions that are consistent with our planned use of the assets , these estimates required significant exercise of judgment and are subject to change in future reporting periods as facts and circumstances change . additionally , we may make changes to our business plan that could result in changes to the expected cash flows . as a result , it is possible that a long- lived asset may be impaired in future reporting periods . stock-based compensation our stock-based compensation expense includes expenses associated with share-based awards granted to employees and board members and expenses associated with our employee stock purchase plan ( “ espp ” ) . the estimated fair value of stock options and espp awards is determined on the date of grant and recorded to expense over the requisite service period , generally the vesting period . we estimate the fair value of stock option awards using the black-scholes option-pricing model which requires judgments to be made , including estimating : ( i ) the expected life of an award ; ( ii ) stock price volatility ; and ( iii ) prior to our initial public offering in february 2011 , the fair value of our common stock . the black-scholes option-pricing model calculates the estimated fair value of stock options using the following inputs : ( i ) expected stock option life ; ( ii ) expected volatility ; ( iii ) risk-free interest rate ; ( iv ) expected dividend yield rate ; ( v ) exercise price ; and ( vi ) closing price of our common stock on the date of grant . due to our limited history of grant activity , we use the “ simplified method ” permitted by the sec to estimate the expected stock option life as the arithmetic average of the total contractual term of the option and its vesting period . we calculate the estimated volatility rate based on selected comparable public companies , due to a lack of historical information regarding the volatility of our stock price . we will continue to analyze the historical stock price volatility assumption as more historical data for our common stock becomes available . the risk-free interest rate assumption is based on the u.s. treasury yield curve in effect on the date of grant for instruments with a term similar to the expected life of the related option . no dividends are expected to be paid . the estimated

