the activity related to the restructuring liability for 2004 is as follows ( in thousands ) : non-operating items interest income increased $ 1.7 million to $ 12.0 million in 2005 from $ 10.3 million in 2004 . the increase was mainly the result of higher returns on invested funds . interest expense decreased $ 1.0 million , or 5% ( 5 % ) , to $ 17.3 million in 2005 from $ 18.3 million in 2004 as a result of the exchange of newly issued stock for a portion of our outstanding convertible debt in the second half of 2005 . in addition , as a result of the issuance during 2005 of common stock in exchange for convertible subordinated notes , we recorded a non- cash charge of $ 48.2 million . this charge related to the incremental shares issued in the transactions over the number of shares that would have been issued upon the conversion of the notes under their original terms . liquidity and capital resources we have incurred operating losses since our inception and historically have financed our operations principally through public and private offerings of our equity and debt securities , strategic collaborative agreements that include research and/or development funding , development milestones and royalties on the sales of products , investment income and proceeds from the issuance of stock under our employee benefit programs . at december 31 , 2006 , we had cash , cash equivalents and marketable securities of $ 761.8 million , which was an increase of $ 354.2 million from $ 407.5 million at december 31 , 2005 . the increase was primarily a result of : 2022 $ 313.7 million in net proceeds from our september 2006 public offering of common stock ; 2022 $ 165.0 million from an up-front payment we received in connection with signing the janssen agreement ; 2022 $ 52.4 million from the issuance of common stock under our employee benefit plans ; and 2022 $ 30.0 million from the sale of shares of altus pharmaceuticals inc . common stock and warrants to purchase altus common stock . these cash inflows were partially offset by the significant cash expenditures we made in 2006 related to research and development expenses and sales , general and administrative expenses . capital expenditures for property and equipment during 2006 were $ 32.4 million . at december 31 , 2006 , we had $ 42.1 million in aggregate principal amount of the 2007 notes and $ 59.6 million in aggregate principal amount of the 2011 notes outstanding . the 2007 notes are due in september 2007 and are convertible into common stock at the option of the holder at a price equal to $ 92.26 per share , subject to adjustment under certain circumstances . in february 2007 , we announced that we will redeem our 2011 notes on march 5 , 2007 . the 2011 notes are convertible into shares of our common stock at the option of the holder at a price equal to $ 14.94 per share . we expect the holders of the 2011 notes will elect to convert their notes into stock , in which case we will issue approximately 4.0 million . we will be required to repay any 2011 notes that are not converted at the rate of $ 1003.19 per $ 1000 principal amount , which includes principal and interest that will accrue to the redemption date . liability as of december 31 , payments in 2004 cash received from sublease , net of operating costs in 2004 additional charge in liability as of december 31 , lease restructuring liability and other operating lease liability $ 69526 $ ( 31550 ) $ 293 $ 17574 $ 55843 .
what is the percent change in cash , cash equivalents and marketable securities between 2005 and 2006?
the activity related to the restructuring liability for 2004 is as follows ( in thousands ) : non-operating items interest income increased $ 1.7 million to $ 12.0 million in 2005 from $ 10.3 million in 2004 . the increase was mainly the result of higher returns on invested funds . interest expense decreased $ 1.0 million , or 5% ( 5 % ) , to $ 17.3 million in 2005 from $ 18.3 million in 2004 as a result of the exchange of newly issued stock for a portion of our outstanding convertible debt in the second half of 2005 . in addition , as a result of the issuance during 2005 of common stock in exchange for convertible subordinated notes , we recorded a non- cash charge of $ 48.2 million . this charge related to the incremental shares issued in the transactions over the number of shares that would have been issued upon the conversion of the notes under their original terms . liquidity and capital resources we have incurred operating losses since our inception and historically have financed our operations principally through public and private offerings of our equity and debt securities , strategic collaborative agreements that include research and/or development funding , development milestones and royalties on the sales of products , investment income and proceeds from the issuance of stock under our employee benefit programs . at december 31 , 2006 , we had cash , cash equivalents and marketable securities of $ 761.8 million , which was an increase of $ 354.2 million from $ 407.5 million at december 31 , 2005 . the increase was primarily a result of : 2022 $ 313.7 million in net proceeds from our september 2006 public offering of common stock ; 2022 $ 165.0 million from an up-front payment we received in connection with signing the janssen agreement ; 2022 $ 52.4 million from the issuance of common stock under our employee benefit plans ; and 2022 $ 30.0 million from the sale of shares of altus pharmaceuticals inc . common stock and warrants to purchase altus common stock . these cash inflows were partially offset by the significant cash expenditures we made in 2006 related to research and development expenses and sales , general and administrative expenses . capital expenditures for property and equipment during 2006 were $ 32.4 million . at december 31 , 2006 , we had $ 42.1 million in aggregate principal amount of the 2007 notes and $ 59.6 million in aggregate principal amount of the 2011 notes outstanding . the 2007 notes are due in september 2007 and are convertible into common stock at the option of the holder at a price equal to $ 92.26 per share , subject to adjustment under certain circumstances . in february 2007 , we announced that we will redeem our 2011 notes on march 5 , 2007 . the 2011 notes are convertible into shares of our common stock at the option of the holder at a price equal to $ 14.94 per share . we expect the holders of the 2011 notes will elect to convert their notes into stock , in which case we will issue approximately 4.0 million . we will be required to repay any 2011 notes that are not converted at the rate of $ 1003.19 per $ 1000 principal amount , which includes principal and interest that will accrue to the redemption date . liability as of december 31 , payments in 2004 cash received from sublease , net of operating costs in 2004 additional charge in liability as of december 31 , lease restructuring liability and other operating lease liability $ 69526 $ ( 31550 ) $ 293 $ 17574 $ 55843 .