icos corporation on january 29 , 2007 , we acquired all of the outstanding common stock of icos corporation ( icos ) , our partner in the lilly icos llc joint venture for the manufacture and sale of cialis for the treatment of erectile dysfunction . the acquisition brought the full value of cialis to us and enabled us to realize operational effi ciencies in the further development , marketing , and selling of this product . the aggregate cash purchase price of approximately $ 2.3 bil- lion was fi nanced through borrowings . the acquisition has been accounted for as a business combination under the purchase method of accounting , resulting in goodwill of $ 646.7 million . no portion of this goodwill was deductible for tax purposes . we determined the following estimated fair values for the assets acquired and liabilities assumed as of the date of acquisition . estimated fair value at january 29 , 2007 .
what percentage of the total purchase price was comprised of goodwill?
1this intangible asset will be amortized over the remaining expected patent lives of cialis in each country ; patent expiry dates range from 2015 to 2017 . new indications for and formulations of the cialis compound in clinical testing at the time of the acquisition represented approximately 48 percent of the estimated fair value of the acquired ipr&d . the remaining value of acquired ipr&d represented several other products in development , with no one asset comprising a signifi cant por- tion of this value . the discount rate we used in valuing the acquired ipr&d projects was 20 percent , and the charge for acquired ipr&d of $ 303.5 million recorded in the fi rst quarter of 2007 was not deductible for tax purposes . other acquisitions during the second quarter of 2007 , we acquired all of the outstanding stock of both hypnion , inc . ( hypnion ) , a privately held neuroscience drug discovery company focused on sleep disorders , and ivy animal health , inc . ( ivy ) , a privately held applied research and pharmaceutical product development company focused on the animal health industry , for $ 445.0 million in cash . the acquisition of hypnion provided us with a broader and more substantive presence in the area of sleep disorder research and ownership of hy10275 , a novel phase ii compound with a dual mechanism of action aimed at promoting better sleep onset and sleep maintenance . this was hypnion 2019s only signifi cant asset . for this acquisi- tion , we recorded an acquired ipr&d charge of $ 291.1 million , which was not deductible for tax purposes . because hypnion was a development-stage company , the transaction was accounted for as an acquisition of assets rather than as a business combination and , therefore , goodwill was not recorded . the acquisition of ivy provides us with products that complement those of our animal health business . this acquisition has been accounted for as a business combination under the purchase method of accounting . we allocated $ 88.7 million of the purchase price to other identifi able intangible assets , primarily related to marketed products , $ 37.0 million to acquired ipr&d , and $ 25.0 million to goodwill . the other identifi able intangible assets are being amortized over their estimated remaining useful lives of 10 to 20 years . the $ 37.0 million allocated to acquired ipr&d was charged to expense in the second quarter of 2007 . goodwill resulting from this acquisition was fully allocated to the animal health business segment . the amount allocated to each of the intangible assets acquired , including goodwill of $ 25.0 million and the acquired ipr&d of $ 37.0 million , was deductible for tax purposes . product acquisitions in june 2008 , we entered into a licensing and development agreement with transpharma medical ltd . ( trans- pharma ) to acquire rights to its product and related drug delivery system for the treatment of osteoporosis . the product , which is administered transdermally using transpharma 2019s proprietary technology , was in phase ii clinical testing , and had no alternative future use . under the arrangement , we also gained non-exclusive access to trans- pharma 2019s viaderm drug delivery system for the product . as with many development-phase products , launch of the .