in addition , there were measurable gains in neurological function in three of the four patients , with the fourth patient clinically stable . we are conducting a phase i/ii clinical trial for the treatment of chronic spinal cord injury . this trial is being conducted in switzerland under authorization from swissmedic , and represents the first time that neural stem cells have been transplanted as a potential therapeutic agent for spinal cord injury . in february 2013 , we announced that the first patient cohort , all of whom had complete spinal cord injuries , had completed the trial . in addition , data from this first cohort continued to demonstrate a favorable safety profile and showed that the considerable gains in sensory function observed at the six month assessment in two of the three patients compared to pre-transplant 42 baselines had persisted at the 12 month assessment ; the third patient remained stable . also , in september 2012 , the first patient with an incomplete spinal cord injury was enrolled and dosed with our hucns-sc cells . in june 2012 , we initiated a phase i/ii clinical trial in dry amd , and in october 2012 , the first patient in this trial was enrolled and dosed . we previously completed a phase i clinical trial in infantile and late infantile neuronal ceroid lipofuscinosis ( ncl ) , and the data from that trial showed that our hucns-sc cells were well tolerated and non-tumorigenic , and that there was evidence of engraftment and long-term survival of the transplanted hucns-sc cells . in july 2012 , the governing board of the california institute for regenerative medicine ( cirm ) approved our application for a disease team award for up to $ 20 million to fund preclinical development of our hucns-sc cells for cervical spinal cord injury ; the funds would have been provided in the form of a forgivable loan . however , in march 2013 , we elected not to borrow these funds from cirm . in september 2012 , the governing board of cirm approved our application for a second , separate disease team award for up to $ 20 million to fund preclinical development of our hucns-sc cells for alzheimer 's disease ; this award would also be in the form of a forgivable loan . negotiation of the terms and conditions for this loan is ongoing . for a brief description of our significant therapeutic research and development programs see overview therapeutic product development programs in the business section of part i , item 1 of this form 10-k. we are also engaged in developing and commercializing applications of our technologies to enable research , which we believe represent current and nearer-term commercial opportunities . our portfolio of technologies includes cell technologies relating to embryonic stem cells , induced pluripotent stem ( ips ) cells , and tissue-derived ( adult ) stem cells ; expertise and infrastructure for providing cell-based assays for drug discovery ; a cell culture products and antibody reagents business ; and an intellectual property portfolio with claims relevant to cell processing , reprogramming and manipulation , as well as to gene targeting and insertion . many of these enabling technologies were acquired in april 2009 as part of our acquisition of the operations of stem cell sciences plc ( scs ) . we have not derived any revenue or cash flows from the sale or commercialization of any products except for license revenue for certain of our patented technologies and sales of products for use in stem cell research . as a result , we have incurred annual operating losses since inception and expect to incur substantial operating losses in the future . therefore , we are dependent upon external financing , such as from equity and debt offerings , to finance our operations . before we can derive revenue or cash inflows from the commercialization of any of our therapeutic product candidates , we will need to : ( i ) conduct substantial in vitro testing and characterization of our proprietary cell types , ( ii ) undertake preclinical and clinical testing for specific disease indications ; ( iii ) develop , validate and scale-up manufacturing processes to produce these cell-based therapeutics , and ( iv ) obtain required regulatory approvals . these steps are risky , expensive and time consuming . overall , we expect our r & d expenses to be substantial and to increase for the foreseeable future as we continue the development and clinical investigation of our current and future product candidates . however , expenditures on r & d programs are subject to many uncertainties , including whether we develop our product candidates with a partner or independently . we can not forecast with any degree of certainty which of our current product candidates will be subject to future collaboration , when such collaboration agreements will be secured , if at all , and to what degree such arrangements would affect our development plans and capital requirements . in addition , there are numerous factors associated with the successful commercialization of any of our cell-based therapeutics , including future trial design and regulatory requirements , many of which can not be determined with accuracy at this time given the stage of our development and the novel nature of stem cell technologies . the regulatory pathways , both in the united states and internationally , are complex and fluid given the novel and , in general , clinically unproven nature of stem cell technologies . at this time , due to such uncertainties and inherent risks , we can not estimate in a meaningful way the duration of , or the costs to complete , our r & d programs or whether , when or to what extent we will generate revenues or cash inflows from the commercialization and sale of any of our therapeutic product candidates . story_separator_special_tag the estimated fair value of our warrant liability at december 31 , 2012 , was approximately $ 9,265,000. stock-based compensation u.s. gaap requires us to recognize expense related to the fair value of our stock-based compensation awards , including employee stock options and restricted stock units . employee stock-based compensation is estimated at the date of grant based on the award 's fair value using the black-scholes option pricing model and is recognized as expense ratably over the requisite service period . the black-scholes option pricing model requires the use of certain assumptions , the most significant of which are our estimates of the expected volatility of the market price of our stock , the expected term of the award , and the risk-free interest rate . our estimate of the expected volatility is based on historical volatility . the expected term represents the period during which our stock-based awards are expected to be outstanding . in 2012 , we estimated this amount based on historical 47 experience of similar awards , giving consideration to the contractual terms of the awards , vesting requirements , and expectation of future employee behavior , including post-vesting terminations . our estimate of the risk-free interest rate is based on u.s. treasury debt securities with maturities close to the expected term of the option as of the date of grant . we review our valuation assumptions at each grant date and , as a result , our assumptions in future periods may change . at the end of each reporting period we estimate forfeiture rates based on our historical experience within separate groups of employees and adjust stock-based compensation expense accordingly . for the year ended december 31 , 2012 , employee and external services stock-based compensation expense ( stock options , restricted stock units and 401 ( k ) plan employer match in form of shares ) was approximately $ 2,878,000. as of december 31 , 2012 , total compensation cost related to unvested stock options and restricted stock units not yet recognized was approximately $ 2,322,000 , which is expected to be recognized as expense over a weighted-average period of 1.7 years . wind-down expenses rhode island in connection with our wind-down of our research and manufacturing operations in lincoln , rhode island , and the relocation of our corporate headquarters and remaining research laboratories to california in october 1999 , we provided a reserve for our estimate of the exit cost obligation . the reserve reflects estimates of the ongoing costs of our former research and administrative facility in lincoln , which we hold on a lease that terminates on june 30 , 2013. in determining the facility exit cost reserve amount , we are required to consider our lease payments through the end of the lease term and estimate other relevant factors such as facility operating expenses , real estate market conditions in rhode island for similar facilities , occupancy rates , and sublease rental rates projected over the course of the leasehold . we re-evaluate the estimate each quarter , taking into account changes , if any , in each of the underlying factors . the process is inherently subjective because it involves projections into time  from the date of the estimate through the end of the lease  and it is not possible to determine any of the factors except the lease payments with certainty over that period . management forms its best estimate on a quarterly basis , after considering actual sublease activity , reports from our broker/realtor about current and predicted real estate market conditions in rhode island , the likelihood of new subleases in the foreseeable future for the specific facility and significant changes in the actual or projected operating expenses of the property . we discount the projected net outflow over the term of the lease to arrive at the present value , and adjust the reserve to that figure . the estimated vacancy rate for the facility is an important assumption in determining the reserve because changes in this assumption have the greatest effect on estimated sublease income . in addition , the vacancy rate estimate is the variable most subject to change , while at the same time it involves the greatest judgment and uncertainty due to the absence of highly predictive information concerning the future of the local economy and future demand for specialized laboratory and office space in that area . the average vacancy rate of the facility over the last ten years ( 2003 through 2012 ) was approximately 73 % , varying from 62 % to 89 % . as of december 31 , 2012 , based on current information available to management , the vacancy rate is projected to be approximately 89 % for the remainder of the lease beginning on january 1 , 2013 and ending on june 30 , 2013. these estimates are based on actual occupancy as of december 31 , 2012 , predicted lead time for acquiring new subtenants , historical vacancy rates for the area and assessments by our broker/realtor of future real estate market conditions . due to the short time remaining on the lease period , the reserve assumes no additional tenants . a 5 % increase or decrease in the operating expenses for the facility for the remaining lease term in 2013 would have increased or decreased the reserve by approximately $ 23,000. management does not wait for specific events to change its estimate , but instead uses its best efforts to anticipate them on a quarterly basis . for the year ended december 31 , 2012 , we recorded actual expenses against this reserve , net of subtenant income , of approximately $ 1,185,000. based on management 's evaluation of the factors mentioned above , and particularly the projected vacancy rates described above , we adjusted the reserve in 2012 by recording an additional $ 356,000 as wind-down expenses . at december 31 , 2012 , the

net cash used in investing activities net cash used in investing activities increased by approximately $ 7,270,000 , or 212 % , in 2012 compared to 2011. the increase was primarily attributable to an increase in net purchases of marketable debt securities in 2012 as compared to 2011. net cash used in investing activities increased by $ 2,498,000 , or 270 % , in 2011 compared to 2010. the increase was primarily attributable to net purchases of marketable debt securities in 2011. no purchases of marketable debt securities were made in 2010. our investment portfolio comprised primarily of u.s. treasury debt securities , which are classified as cash equivalents and commercial paper and corporate debt securities , which are classified as short-term marketable securities , with no positions held in-long term marketable debt securities . net cash provided by financing activities the increases in cash provided by financing activities from 2010 to 2012 were primarily attributable to higher net proceeds from sales of our common stock . 55 listed below are key financing transactions entered into by us in 2012 , 2011 and 2010 : in 2012 , we sold an aggregate of 9,647,471 shares of our common stock at an average price per share of $ 2.12 for gross proceeds of approximately $ 20,452,000. these sales were made under a sales agreement entered into in june 2009 ( 2009 sales agreement ) and the sales agent was paid compensation equal to 3 % of gross proceeds . the shares were offered under our shelf registration statement previously filed with , and declared effective by , the sec .


 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 used in investing activities net cash used in investing activities increased by approximately $ 7,270,000 , or 212 % , in 2012 compared to 2011. the increase was primarily attributable to an increase in net purchases of marketable debt securities in 2012 as compared to 2011. net cash used in investing activities increased by $ 2,498,000 , or 270 % , in 2011 compared to 2010. the increase was primarily attributable to net purchases of marketable debt securities in 2011. no purchases of marketable debt securities were made in 2010. our investment portfolio comprised primarily of u.s. treasury debt securities , which are classified as cash equivalents and commercial paper and corporate debt securities , which are classified as short-term marketable securities , with no positions held in-long term marketable debt securities . net cash provided by financing activities the increases in cash provided by financing activities from 2010 to 2012 were primarily attributable to higher net proceeds from sales of our common stock . 55 listed below are key financing transactions entered into by us in 2012 , 2011 and 2010 : in 2012 , we sold an aggregate of 9,647,471 shares of our common stock at an average price per share of $ 2.12 for gross proceeds of approximately $ 20,452,000. these sales were made under a sales agreement entered into in june 2009 ( 2009 sales agreement ) and the sales agent was paid compensation equal to 3 % of gross proceeds . the shares were offered under our shelf registration statement previously filed with , and declared effective by , the sec .
```    
 Suspicious Activity Report : in addition , there were measurable gains in neurological function in three of the four patients , with the fourth patient clinically stable . we are conducting a phase i/ii clinical trial for the treatment of chronic spinal cord injury . this trial is being conducted in switzerland under authorization from swissmedic , and represents the first time that neural stem cells have been transplanted as a potential therapeutic agent for spinal cord injury . in february 2013 , we announced that the first patient cohort , all of whom had complete spinal cord injuries , had completed the trial . in addition , data from this first cohort continued to demonstrate a favorable safety profile and showed that the considerable gains in sensory function observed at the six month assessment in two of the three patients compared to pre-transplant 42 baselines had persisted at the 12 month assessment ; the third patient remained stable . also , in september 2012 , the first patient with an incomplete spinal cord injury was enrolled and dosed with our hucns-sc cells . in june 2012 , we initiated a phase i/ii clinical trial in dry amd , and in october 2012 , the first patient in this trial was enrolled and dosed . we previously completed a phase i clinical trial in infantile and late infantile neuronal ceroid lipofuscinosis ( ncl ) , and the data from that trial showed that our hucns-sc cells were well tolerated and non-tumorigenic , and that there was evidence of engraftment and long-term survival of the transplanted hucns-sc cells . in july 2012 , the governing board of the california institute for regenerative medicine ( cirm ) approved our application for a disease team award for up to $ 20 million to fund preclinical development of our hucns-sc cells for cervical spinal cord injury ; the funds would have been provided in the form of a forgivable loan . however , in march 2013 , we elected not to borrow these funds from cirm . in september 2012 , the governing board of cirm approved our application for a second , separate disease team award for up to $ 20 million to fund preclinical development of our hucns-sc cells for alzheimer 's disease ; this award would also be in the form of a forgivable loan . negotiation of the terms and conditions for this loan is ongoing . for a brief description of our significant therapeutic research and development programs see overview therapeutic product development programs in the business section of part i , item 1 of this form 10-k. we are also engaged in developing and commercializing applications of our technologies to enable research , which we believe represent current and nearer-term commercial opportunities . our portfolio of technologies includes cell technologies relating to embryonic stem cells , induced pluripotent stem ( ips ) cells , and tissue-derived ( adult ) stem cells ; expertise and infrastructure for providing cell-based assays for drug discovery ; a cell culture products and antibody reagents business ; and an intellectual property portfolio with claims relevant to cell processing , reprogramming and manipulation , as well as to gene targeting and insertion . many of these enabling technologies were acquired in april 2009 as part of our acquisition of the operations of stem cell sciences plc ( scs ) . we have not derived any revenue or cash flows from the sale or commercialization of any products except for license revenue for certain of our patented technologies and sales of products for use in stem cell research . as a result , we have incurred annual operating losses since inception and expect to incur substantial operating losses in the future . therefore , we are dependent upon external financing , such as from equity and debt offerings , to finance our operations . before we can derive revenue or cash inflows from the commercialization of any of our therapeutic product candidates , we will need to : ( i ) conduct substantial in vitro testing and characterization of our proprietary cell types , ( ii ) undertake preclinical and clinical testing for specific disease indications ; ( iii ) develop , validate and scale-up manufacturing processes to produce these cell-based therapeutics , and ( iv ) obtain required regulatory approvals . these steps are risky , expensive and time consuming . overall , we expect our r & d expenses to be substantial and to increase for the foreseeable future as we continue the development and clinical investigation of our current and future product candidates . however , expenditures on r & d programs are subject to many uncertainties , including whether we develop our product candidates with a partner or independently . we can not forecast with any degree of certainty which of our current product candidates will be subject to future collaboration , when such collaboration agreements will be secured , if at all , and to what degree such arrangements would affect our development plans and capital requirements . in addition , there are numerous factors associated with the successful commercialization of any of our cell-based therapeutics , including future trial design and regulatory requirements , many of which can not be determined with accuracy at this time given the stage of our development and the novel nature of stem cell technologies . the regulatory pathways , both in the united states and internationally , are complex and fluid given the novel and , in general , clinically unproven nature of stem cell technologies . at this time , due to such uncertainties and inherent risks , we can not estimate in a meaningful way the duration of , or the costs to complete , our r & d programs or whether , when or to what extent we will generate revenues or cash inflows from the commercialization and sale of any of our therapeutic product candidates . story_separator_special_tag the estimated fair value of our warrant liability at december 31 , 2012 , was approximately $ 9,265,000. stock-based compensation u.s. gaap requires us to recognize expense related to the fair value of our stock-based compensation awards , including employee stock options and restricted stock units . employee stock-based compensation is estimated at the date of grant based on the award 's fair value using the black-scholes option pricing model and is recognized as expense ratably over the requisite service period . the black-scholes option pricing model requires the use of certain assumptions , the most significant of which are our estimates of the expected volatility of the market price of our stock , the expected term of the award , and the risk-free interest rate . our estimate of the expected volatility is based on historical volatility . the expected term represents the period during which our stock-based awards are expected to be outstanding . in 2012 , we estimated this amount based on historical 47 experience of similar awards , giving consideration to the contractual terms of the awards , vesting requirements , and expectation of future employee behavior , including post-vesting terminations . our estimate of the risk-free interest rate is based on u.s. treasury debt securities with maturities close to the expected term of the option as of the date of grant . we review our valuation assumptions at each grant date and , as a result , our assumptions in future periods may change . at the end of each reporting period we estimate forfeiture rates based on our historical experience within separate groups of employees and adjust stock-based compensation expense accordingly . for the year ended december 31 , 2012 , employee and external services stock-based compensation expense ( stock options , restricted stock units and 401 ( k ) plan employer match in form of shares ) was approximately $ 2,878,000. as of december 31 , 2012 , total compensation cost related to unvested stock options and restricted stock units not yet recognized was approximately $ 2,322,000 , which is expected to be recognized as expense over a weighted-average period of 1.7 years . wind-down expenses rhode island in connection with our wind-down of our research and manufacturing operations in lincoln , rhode island , and the relocation of our corporate headquarters and remaining research laboratories to california in october 1999 , we provided a reserve for our estimate of the exit cost obligation . the reserve reflects estimates of the ongoing costs of our former research and administrative facility in lincoln , which we hold on a lease that terminates on june 30 , 2013. in determining the facility exit cost reserve amount , we are required to consider our lease payments through the end of the lease term and estimate other relevant factors such as facility operating expenses , real estate market conditions in rhode island for similar facilities , occupancy rates , and sublease rental rates projected over the course of the leasehold . we re-evaluate the estimate each quarter , taking into account changes , if any , in each of the underlying factors . the process is inherently subjective because it involves projections into time  from the date of the estimate through the end of the lease  and it is not possible to determine any of the factors except the lease payments with certainty over that period . management forms its best estimate on a quarterly basis , after considering actual sublease activity , reports from our broker/realtor about current and predicted real estate market conditions in rhode island , the likelihood of new subleases in the foreseeable future for the specific facility and significant changes in the actual or projected operating expenses of the property . we discount the projected net outflow over the term of the lease to arrive at the present value , and adjust the reserve to that figure . the estimated vacancy rate for the facility is an important assumption in determining the reserve because changes in this assumption have the greatest effect on estimated sublease income . in addition , the vacancy rate estimate is the variable most subject to change , while at the same time it involves the greatest judgment and uncertainty due to the absence of highly predictive information concerning the future of the local economy and future demand for specialized laboratory and office space in that area . the average vacancy rate of the facility over the last ten years ( 2003 through 2012 ) was approximately 73 % , varying from 62 % to 89 % . as of december 31 , 2012 , based on current information available to management , the vacancy rate is projected to be approximately 89 % for the remainder of the lease beginning on january 1 , 2013 and ending on june 30 , 2013. these estimates are based on actual occupancy as of december 31 , 2012 , predicted lead time for acquiring new subtenants , historical vacancy rates for the area and assessments by our broker/realtor of future real estate market conditions . due to the short time remaining on the lease period , the reserve assumes no additional tenants . a 5 % increase or decrease in the operating expenses for the facility for the remaining lease term in 2013 would have increased or decreased the reserve by approximately $ 23,000. management does not wait for specific events to change its estimate , but instead uses its best efforts to anticipate them on a quarterly basis . for the year ended december 31 , 2012 , we recorded actual expenses against this reserve , net of subtenant income , of approximately $ 1,185,000. based on management 's evaluation of the factors mentioned above , and particularly the projected vacancy rates described above , we adjusted the reserve in 2012 by recording an additional $ 356,000 as wind-down expenses . at december 31 , 2012 , the

