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Consolidated Balance Sheets - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009
Current assets:
Cash and cash equivalents	$ 243,197	$ 446,658
Marketable securities, available for sale	788,214	838,255
Accounts receivable	12,529	9,601
Prepaid expenses and other current assets	13,099	12,512
Total current assets	1,057,039	1,307,026
Restricted cash	34,090	30,313
Property and equipment, net	72,333	62,279
Intangible assets	518,700	518,700
Goodwill	26,102	26,102
Other assets	17,182	11,068
Total assets	1,725,446	1,955,488
Current liabilities:
Accounts payable	35,851	36,989
Accrued expenses and other current liabilities	134,414	118,753
Accrued interest	3,462	571
Deferred revenues, current portion	74,619	74,956
Accrued restructuring expense, current portion	5,497	6,316
Convertible senior subordinated notes (due 2013), current portion		32,071
Secured notes (due 2012), current portion	136,991
Liability related to sale of potential future milestone payments, current portion	77,799
Other obligations	6,150	15,227
Total current liabilities	474,783	284,883
Deferred revenues, excluding current portion	160,049	225,575
Accrued restructuring expense, excluding current portion	24,098	27,701
Convertible senior subordinated notes (due 2015)	400,000
Secured notes (due 2012), excluding current portion		121,765
Liability related to sale of potential future milestone payments, excluding current portion		38,207
Deferred tax liability	160,278	160,278
Other liabilities	2,265	733
Total liabilities	$ 1,221,473	$ 859,142
Commitments and contingencies (Note K and Note T)
Stockholders' equity:
Preferred stock, $0.01 par value; 1,000,000 shares authorized; none issued and outstanding at December 31, 2010 and 2009
Common stock, $0.01 par value; 300,000,000 shares authorized at December 31, 2010 and 2009; 203,522,976 and 199,955,023 shares issued and outstanding at December 31, 2010 and 2009, respectively	2,016	1,982
Additional paid-in capital	3,947,433	3,784,787
Accumulated other comprehensive loss	(1,067)	(640)
Accumulated deficit	(3,444,409)	(2,689,783)
Total stockholders' equity	503,973	1,096,346
Total liabilities and stockholders' equity	$ 1,725,446	$ 1,955,488

Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2010

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iBasis of Presentation/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated. The Company operates in one segment, pharmaceuticals, and all revenues are from United States operations. /font/p/td/tr/table

Use of Estimates

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iUse of Estimates /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The preparation of consolidated financial statements in conformity with United States generally accepted accounting principles requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of revenues and expenses during the reported periods. Significant estimates in these consolidated financial statements have been made in connection with the calculation of revenues, research and development expenses, stock-based compensation expense, pre-approval inventories, restructuring expense, the value of intangible assets, derivative instruments and debt securities. The Company bases its estimates on historical experience and various other assumptions, including in certain circumstances future projection s, that management believes to be reasonable under the circumstances. Actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known. /font/p/td/tr/table

Concentration of Credit Risk

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist principally of money market funds and marketable securities. The Company places these investments with highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in these accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no foreign exchange contracts, option contracts or other foreign exchange hedging arrangements.

The Company's revenues have been generated from a limited number of collaborators in the biotechnology and pharmaceuticals industries in the United States, Europe and Japan. In 2010, the Company had significant revenue transactions with Mitsubishi Tanabe Pharma Corporation ("Mitsubishi Tanabe") and Janssen Pharmaceutica, N.V. ("Janssen") that accounted for 57% and 21%, respectively, of the Company's total revenues. In 2009, the Company had significant revenue transactions with Janssen and Mitsubishi Tanabe that accounted for 54% and 18%, respectively, of the Company's total revenues. In 2008, the Company had significant revenue transactions with Janssen that accounted for 68% of the Company's total revenues.

Receivables from Mitsubishi Tanabe, GlaxoSmithKline plc and Janssen represented 55%, 23% and 12%, respectively, of the Company's accounts receivable balance at December 31, 2010. Receivables from Janssen, GlaxoSmithKline plc and Mitsubishi Tanabe represented 36%, 36% and 15%, respectively, of the Company's accounts receivable balance at December 31, 2009. Management believes that credit risks associated with these collaborators are not significant.

Cash and Cash Equivalents

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist principally of money market funds and debt securities. Changes in cash and cash equivalents may be affected by shifts in investment portfolio maturities as well as by actual cash receipts and disbursements.

Marketable Securities

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td table style="FONT-SIZE: 10pt; FONT-FAMILY: 'Times New Roman',times,serif" tr td p style="FONT-FAMILY: times"font size="2"iMarketable Securities/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Marketable securities consist of investments in U.S. Treasuries, government-sponsored enterprise securities and high-grade corporate bonds and commercial paper that are classified as available-for-sale. The Company classifies marketable securities available to fund current operations as current assets on the consolidated balance sheets. Marketable securities are classified as long-term assets on the consolidated balance sheets if (i)nbsp;they have been in an unrealized loss position for longer than one year and (ii)nbsp;the Company has the ability and intent to hold them (a)nbsp;until the carrying value is recovered and (b)nbsp;such holding period may be longer than one year. Marketable securities are stated at fair value with their unrealized gains and losses included as a component of accumulated other comprehensive income (loss), which is a separate c omponent of stockholders' equity, until such gains and losses are realized. The fair value of these securities is based on quoted prices for identical or similar assets. If a decline in the fair value is considered other-than-temporary, based on available evidence, the unrealized loss is transferred from other comprehensive income (loss) to the consolidated statements of operations. There were no charges taken for other than temporary declines in fair value of marketable securities in 2010, 2009 or 2008. Realized gains and losses are determined on the specific identification method and are included in interest income in the consolidated statements of operations. Please refer to Notenbsp;G, "Marketable Securities," for further information./font/p/td/tr/table/td/tr/table

Stock-based Compensation Expense

Stock-based Compensation Expense

The Company expenses the fair value of employee stock options and other forms of stock-based employee compensation over the associated employee service period or for awards with market conditions, the derived service period. For awards with performance conditions, the Company makes estimates regarding the likelihood of satisfaction of the performance conditions that affect the period over which the expense is recognized. Compensation expense is determined based on the fair value of the award at the grant date, including estimated forfeitures, and is adjusted to reflect actual forfeitures and the outcomes of certain market and performance conditions. Please refer to Note D, "Stock-based Compensation Expense," for further information.

Research and Development Expenses

Research and Development Expenses

All research and development expenses, including amounts funded by research and development collaborations, are expensed as incurred. The Company defers and capitalizes nonrefundable advance payments made by the Company for research and development activities until the related goods are delivered or the related services are performed.

Research and development expenses are comprised of costs incurred by the Company in performing research and development activities, including salary and benefits; stock-based compensation expense; laboratory supplies and other direct expenses; contractual services costs, including clinical trial and pharmaceutical development costs; expenses associated with commercial supply investment in its drug candidates; and infrastructure costs, including facilities costs and depreciation expense. The Company evaluates periodically whether a portion of its commercial supply investment may be capitalized as inventory. Generally, inventory may be capitalized if it is probable that future revenues will be generated from the sale of the inventory and that these revenues will exceed the cost of the inventory. In 2010, the Company continued to expense all of its commercial supply investment due to the high risk inherent in drug development.

The Company's collaborators have funded portions of the Company's research and development programs related to specific drug candidates and research targets, including telaprevir in 2010 and 2009; and telaprevir, certain kinases and certain cystic fibrosis research targets in 2008. The Company's collaborative revenues were $113.1 million, $73.6 million and $138.0 million, respectively, for 2010, 2009 and 2008. The Company's research and development expenses allocated to programs in which a collaborator funded at least a portion of the research and development expenses were approximately $156 million, approximately $149 million and approximately $156 million, respectively, for 2010, 2009 and 2008.

Pre-approval Inventories

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iPre-approval Inventories/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company capitalizes inventories produced in preparation for initiating sales of a drug candidate when the related drug candidate is considered to have a high probability of regulatory approval and the related costs are expected to be recoverable through sales of the drug. As of Decembernbsp;31, 2010, the Company had not yet capitalized any inventory costs for telaprevir manufactured in preparation for its expected product launch in 2011. The Company has submitted its NDA for telaprevir to the FDA, and the target date for the FDA to complete its review of the telaprevir NDA is Maynbsp;23, 2011. The Company expects to begin to capitalize inventory costs for telaprevir in 2011. /font/p/td/tr/table

Restructuring Expense

Restructuring Expense

The Company records costs and liabilities associated with exit and disposal activities based on estimates of fair value in the period the liabilities are incurred. In periods subsequent to initial measurement, changes to the liability are measured using the credit-adjusted risk-free discount rate applied in the initial period. Liabilities are evaluated and adjusted as appropriate for changes in circumstances at least on a quarterly basis. Please refer to Note F, "Restructuring Expense," for further information.

Revenue Recognition

Revenue Recognition

Collaborative Revenues

The Company's revenues are generated primarily through collaborative research, development and/or commercialization agreements. The terms of these agreements typically include payment to the Company of one or more of the following: nonrefundable, up-front license fees; milestone payments; funding of research and/or development activities; payments for services the Company provides through its third-party manufacturing network; and royalties on product sales. Each of these types of payments results in collaborative revenues, except for revenues from royalties on product sales, which are classified as royalty revenues.

Agreements containing multiple elements are divided into separate units of accounting if certain criteria are met, including whether the delivered element has stand-alone value to the collaborator and whether there is objective and reliable evidence of the fair value of the undelivered obligation(s). The consideration received is allocated among the separate units either on the basis of each unit's fair value or using the residual method, and the applicable revenue recognition criteria are applied to each of the separate units.

Up-front License Fees

The Company recognizes revenues from nonrefundable, up-front license fees on a straight-line basis over the contracted or estimated period of performance, which is typically the period over which the research and development is expected to occur or manufacturing services are expected to be provided. In order to estimate the period of performance, the Company is required to make estimates regarding the drug development and commercialization timelines for drug candidates being developed pursuant to the applicable agreement. The Company's estimates regarding the period of performance under certain of its collaboration agreements have changed in the past and may change in the future.

Milestone Payments

At the inception of each agreement that includes milestone payments, the Company evaluates whether each milestone is substantive on the basis of the contingent nature of the milestone, specifically reviewing factors such as the scientific and other risks that must be overcome to achieve the milestone, as well as the level of effort and investment required. The Company recognizes revenues related to substantive milestones in full in the period in which the substantive milestone is achieved, if payment is reasonably assured and the Company's performance obligations are fully satisfied or if the Company has fair value for its remaining obligations. If the Company has remaining obligations after the achievement of a substantive milestone and does not have sufficient evidence of the fair value of those obligations, the milestone payment is recognized over the period of performan ce. If a milestone payment is not considered substantive, the Company recognizes the applicable milestone over the remaining period of performance.

Research and Development Activities/Manufacturing Services

Under certain of its collaboration agreements, the Company is entitled to reimbursement from its collaborators for specified research and development expenses and/or payments for specified manufacturing services that the Company provides through its third-party manufacturing network. The Company considers the nature and contractual terms of the arrangement and the nature of the Company's business operations in order to determine whether research and development funding will result in collaborative revenues or an offset to research and development expenses. The Company typically recognizes the revenues related to these reimbursable expenses and manufacturing services in the period in which the reimbursable expenses are incurred or the manufacturing services are provided.

Royalty Revenues

Royalty revenues typically are recognized based upon actual and estimated net sales of licensed products in licensed territories, as provided by the licensee, and generally are recognized in the period the sales occur. The Company reconciles and adjusts for differences between actual royalty revenues and estimated royalty revenues in the quarter they become known. These differences historically have not been significant.

The Company has sold its rights to certain royalties on sales of HIV protease inhibitors and recognizes the revenues related to this sale as royalty revenues. In the circumstance where the Company has sold its rights to future royalties under a license agreement and also maintains continuing involvement in the royalty arrangement (but not significant continuing involvement in the generation of the cash flows due to the purchaser of the future royalty rights), the Company defers recognition of the proceeds it receives for the royalty stream and recognizes these deferred revenues over the life of the license agreement. The Company recognizes these deferred revenues pursuant to the units-of-revenue method. Under this method, the amount of deferred revenues to be recognized as royalty revenues in each period is calculated by multiplying the following: (1) the royalty p ayments due to the purchaser for the period by (2) the ratio of the remaining deferred revenue amount to the total estimated remaining royalty payments due to the purchaser over the term of the agreement. The Company's estimates regarding the estimated remaining royalty payments due to the purchaser have changed in the past and may change in the future.

Property and Equipment.

Property and Equipment

Property and equipment are recorded at cost. Depreciation and amortization is provided using the straight-line method over the estimated useful life of the related asset, generally four to seven years for furniture and equipment and three to five years for computers and software. Leasehold improvements are amortized using the straight-line method over the lesser of the useful life of the improvements or the remaining life of the associated lease. Major additions and betterments are capitalized. Maintenance and repairs to an asset that do not improve or extend its life are charged to operations. When assets are retired or otherwise disposed of, the assets and related allowances for depreciation and amortization are eliminated from the accounts and any resulting gain or loss is reflected in the Company's consolidated statements of operations.

Income Taxes

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iIncome Taxes /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement carrying amounts and the income tax bases of assets and liabilities. A valuation allowance is applied against any net deferred tax asset if, based on the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized./font/p/td/tr/table

Financial Transaction Expenses

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iFinancial Transaction Expenses/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Issuance costs incurred to complete the Company's convertible senior subordinated note offerings and the financial transactions that the Company entered into in September 2009 are deferred and included in other assets on the Company's consolidated balance sheets. The issuance costs are amortized using the effective interest rate method over the term of the related debt or financial instrument. The amortization expense related to the issuance costs is included in interest expense on the consolidated statements of operations. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company defers direct and incremental costs associated with the sale of its rights to future royalties. These costs are included in other assets on the Company's consolidated balance sheets and are amortized in the same manner and over the same period during which the related deferred revenues are recognized as royalty revenues. The amortization expense related to these transaction expenses is included in royalty expenses on the consolidated statements of operations./font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Expenses incurred in connection with common stock issuances are recorded as an offset to additional paid-in capital on the consolidated balance sheets. /font/p/td/tr/table

Business Combinations

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iBusiness Combinations/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company assigns the value of the consideration transferred to acquire a business to the tangible assets and identifiable intangible assets acquired and liabilities assumed on the basis of their fair values at the date of acquisition. The Company assesses the fair value of assets, including intangible assets such as in-process research and development assets, using a variety of methods. Each asset is measured at fair value from the perspective of a market participant. The present-value models used to estimate the fair values of in-process research and development assets incorporate significant assumptions regarding the estimates that market participants would make in order to evaluate an asset: including market participants' assumptions regarding the probability of completing in-process research and development projects, which would require obtaining regulatory approval for marketing of the associated drug candidate; market participants' estimates regarding the timing of and the expected costs to complete in-process research and development projects; market participants' estimates of future cash flows from potential product sales; and the appropriate discount rates for market participants. Transaction costs and restructuring costs associated with the transaction are expensed as incurred. /font/p/td/tr/table

In-process Research and Development Assets

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iIn-process Research and Development Assets /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In-process research and development assets acquired in a business combination are recorded as of the acquisition date at fair value and accounted for as indefinite-lived intangible assets. These assets are maintained on the Company's consolidated balance sheets until either the project underlying them is completed or the assets become impaired. If a project is completed, the carrying value of the related intangible asset is amortized as a part of cost of revenues over the remaining estimated life of the asset beginning in the period in which the project is completed. If a project becomes impaired or is abandoned, the carrying value of the related intangible asset is written down to its fair value and an impairment charge is taken in the period in which the impairment occurs. In-process research and development assets relate to the Company's acquisition of ViroChem in March 2009. In-process research and development assets are tested for impairment on an annual basis as of Octobernbsp;1, and more frequently if indicators are present or changes in circumstances suggest that impairment may exist. /font/p/td/tr/table

Goodwill

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iGoodwill /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The difference between the purchase price and the fair value of assets acquired and liabilities assumed in a business combination is allocated to goodwill. Goodwill relates to the Company's acquisition of ViroChem in March 2009. Goodwill is evaluated for impairment on an annual basis as of Octobernbsp;1, and more frequently if indicators are present or changes in circumstances suggest that impairment may exist. /font/p/td/tr/table

Derivative Instruments and Embedded Derivatives

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iDerivative Instruments and Embedded Derivatives /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company has entered into financial transactions involving a free-standing derivative instrument and embedded derivatives. These financial transactions include arrangements involving secured notes, the sale of potential future milestone payments and senior subordinated convertible notes. The embedded derivatives are required to be bifurcated from the host instruments because the derivatives are not clearly and closely related to the host instruments. The Company determines the fair value of each derivative instrument or embedded derivative on the date of issuance. The estimates of the fair value of these derivatives, particularly with respect to derivatives related to the achievement of milestones in the development of telaprevir, include significant assumptions regarding the estimates market participants would make in order to evaluate these derivatives. Changes in the fair value of these derivatives are evaluated on a quarterly basis. Please refer to Notenbsp;Q, "September 2009 Financial Transactions," for further information. /font/p/td/tr/table

Comprehensive Loss

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iComprehensive Loss /i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Comprehensive loss consists of net loss and other comprehensive income (loss), which includes foreign currency translation adjustments, reclassification adjustment for realized gain (loss) on marketable securities included in net loss, and unrealized gains and losses on certain marketable securities. For purposes of comprehensive loss disclosures, the Company does not record tax provisions or benefits for the net changes in foreign currency translation adjustment, as the Company intends to permanently reinvest undistributed earnings in its foreign subsidiaries. /font/p/td/tr/table

Foreign Currency Translation

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iForeign Currency Translation/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;All consolidated entities have the U.S. dollar as their functional currency except the functional currency of the Company's United Kingdom subsidiary for all periods and the Company's Canadian subsidiaries prior to Januarynbsp;1, 2010 is the local currency. Non-U.S. dollar functional currency subsidiaries have assets and liabilities translated into U.S. dollars at rates of exchange in effect at the end of the year. Revenue and expense amounts are translated using the average exchange rates for the period. Net unrealized gains and losses resulting from foreign currency translation are included in accumulated other comprehensive income (loss), which is a separate component of stockholders' equity. Included in accumulated other comprehensive income (loss) is a net unrealized loss related to foreign currency translation of $1.1nbsp;million at Decembernbsp;31, 201 0, a net unrealized loss related to foreign currency translation of $0.6nbsp;million at Decembernbsp;31, 2009 and a net unrealized gain related to foreign currency translation of $27,000 at Decembernbsp;31, 2008. /font/p/td/tr/table

Basic and Diluted Net Loss per Common Share

Basic and Diluted Net Loss per Common Share

Basic net loss per common share is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock and restricted stock units that have been issued but are not yet vested. Diluted net loss per common share is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average common equivalent shares outstanding during the period when the effect is dilutive. Common equivalent shares result from the assumed exercise of outstanding stock options (the proceeds of which are then assumed to have been used to repurchase outstanding stock using the treasury stock method), the assumed conversion of convertible notes and the vesting of unvested restricted stock and restricted stock units. Common equivalent shares have not been included in the net loss per common share calculations be cause the effect would have been anti-dilutive. Total potential gross common equivalent shares consisted of the following:

		At December 31,

		2010		2009		2008
		(in thousands, except per share amounts)
Stock options			21,293		19,232		16,497
	Weighted-average exercise price (per share)	$	30.50	$	31.38	$	29.16
Convertible senior subordinated notes			8,192		1,386		12,425
	Conversion price (per share)	$	48.83	$	23.14	$	23.14
Unvested restricted stock and restricted stock units			1,950		1,727		1,851

Recent Accounting Pronouncements

table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2"iRecent Accounting Pronouncements/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In December 2010, the Financial Accounting Standards Board ("FASB") provided guidance to clarify how pharmaceutical manufacturers should recognize and classify in their consolidated statements of operations the fees mandated by the recently enacted Patient Protection and Affordable Care Act as amended by the Health Care and Education Reconciliation Act. The fees are not tax deductible and are imposed on manufacturers annually based on their share of the pharmaceutical industry's branded drug sales for the preceding year. The portion allocated to an individual manufacturer becomes payable to the U.S. Treasury once the manufacturer has qualifying gross receipts from branded prescription drug sales. The liability for the fee will be estimated and recorded in full upon the first qualifying sale with a corresponding deferred cost that is amortized to expense using a straight-lin e method of allocation unless another method better allocates the fee over the calendar year in which it is payable. The annual fee will be presented as an operating expense. The guidance became effective for the Company on Januarynbsp;1, 2011. As this guidance relates only to classification, the adoption of this guidance will not have an effect on the Company's consolidated financial statements. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In April 2010, FASB provided updated guidance on defining a milestone and determining when it may be appropriate to apply the milestone method of revenue recognition for research and development transactions. The update became effective and was adopted by the Company on a prospective basis for milestones achieved beginning on Januarynbsp;1, 2011. The updated guidance is consistent with the accounting policies that the Company has used with respect to the recognition of milestone revenues during the three year period ending Decembernbsp;31, 2010. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In September 2009, the FASB provided updated guidance (1)nbsp;on whether multiple deliverables exist, how the deliverables in a revenue arrangement should be separated and how the consideration should be allocated; (2)nbsp;requiring companies to allocate revenues in an arrangement using estimated selling prices of deliverables if a vendor does not have vendor-specific objective evidence or third-party evidence of selling price; and (3)nbsp;eliminating the use of the residual method and requiring companies to allocate revenues using the relative selling price method. The updated guidance became effective for the Company on Januarynbsp;1, 2011. The Company adopted the updated guidance on a prospective basis and it will apply to revenue arrangements entered into or materially modified after Decembernbsp;31, 2010. /font/p/td/ tr/table

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2010	Dec. 31, 2009
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	203,522,976	199,955,023
Common stock, shares outstanding	203,522,976	199,955,023

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended				84 Months Ended
	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2009	Mar. 31, 2009	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2003	Dec. 31, 2010
Revenues:
Royalty revenues	$ 8,402	$ 8,173	$ 7,262	$ 6,407	$ 8,429	$ 7,834	$ 5,917	$ 6,140	$ 30,244	$ 28,320	$ 37,483
Collaborative revenues	57,122	15,622	24,360	16,022	25,460	17,123	13,147	17,839	113,126	73,569	138,021
Total revenues	65,524	23,795	31,622	22,429	33,889	24,957	19,064	23,979	143,370	101,889	175,504
Costs and expenses:
Royalty expenses	3,049	3,228	3,086	3,367	3,647	3,712	3,267	3,576	12,730	14,202	15,686
Research and development expenses	168,888	170,434	155,082	143,012	135,230	132,132	139,331	143,581	637,416	550,274	516,912
Sales, general and administrative expenses	62,478	48,855	40,915	35,552	32,574	36,572	32,526	28,520	187,800	130,192	101,290
Restructuring expense	(2,257)	866	2,112	780	1,957	774	1,107	2,402	1,501	6,240	4,324	$ 91,824	$ 58,561
Intangible asset impairment charges					7,200					7,200
Acquisition-related expenses								7,793		7,793
Total costs and expenses	232,158	223,383	201,195	182,711	180,608	173,190	176,231	185,872	839,447	715,901	638,212
Loss from operations	(166,634)	(199,588)	(169,573)	(160,282)	(146,719)	(148,233)	(157,167)	(161,893)	(696,077)	(614,012)	(462,708)
Interest income	523	493	484	455	327	595	1,489	2,599	1,955	5,010	16,328
Interest expense	(7,686)	(3,951)	(3,683)	(3,955)	(4,562)	(1,927)	(3,325)	(3,378)	(19,275)	(13,192)	(13,471)
Change in fair value of derivative instruments	(6,595)	(5,911)	(27,234)	(1,489)	(1,847)				(41,229)	(1,847)
Loss on exchanges of convertible senior subordinated notes (due 2013)					(5,843)		(12,294)			(18,137)
Net loss	$ (180,392)	$ (208,957)	$ (200,006)	$ (165,271)	$ (158,644)	$ (149,565)	$ (171,297)	$ (162,672)	$ (754,626)	$ (642,178)	$ (459,851)
Basic net loss per common share (in dollars per share)	$ (0.90)	$ (1.04)	$ (1.00)	$ (0.83)	$ (0.86)	$ (0.84)	$ (0.99)	$ (1.04)	$ (3.77)	$ (3.71)	$ (3.27)
Diluted net loss per common share (in dollars per share)	$ (0.90)	$ (1.04)	$ (1.00)	$ (0.83)	$ (0.86)	$ (0.84)	$ (0.99)	$ (1.04)	$ (3.77)	$ (3.71)	$ (3.27)
Basic weighted-average number of common shares outstanding (in shares)	201,355	200,887	200,397	198,935	185,492	178,735	172,563	155,860	200,402	173,259	140,556
Diluted weighted-average number of common shares outstanding (in shares)	201,355	200,887	200,397	198,935	185,492	178,735	172,563	155,860	200,402	173,259	140,556

Consolidated Statements of Stockholders' Equity and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2010	Mar. 31, 2010	Dec. 31, 2009	Mar. 31, 2009	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Increase (Decrease) in Stockholders' Equity
Balance		$ 1,096,346		$ 238,874	$ 1,096,346	$ 238,874	$ 271,295
Balance (in shares)		199,955,023			199,955,023
Unrealized holding gains (losses) on marketable securities					$ 46	(3,178)	3,683
Reclassification adjustment for realized loss on marketable securities included in net loss							(1,242)
Translation adjustments					(473)	(630)	(154)
Net loss	$ (180,392)	$ (165,271)	$ (158,644)	(162,672)	(754,626)	(642,178)	(459,851)
Issuances of common stock:
Convertible senior subordinated notes (due 2013) exchanges						270,892
Acquisition of ViroChem						290,557
Equity offerings						801,385	330,145
Convertible senior subordinated notes (due 2013) conversion					31,565
Benefit plans					39,991	53,902	37,013
Stock-based compensation expense					91,124	86,722	57,985
Balance	$ 503,973		$ 1,096,346		$ 503,973	$ 1,096,346	238,874
Balance (in shares)	203,522,976		199,955,023		203,522,976	199,955,023
Common Stock
Increase (Decrease) in Stockholders' Equity
Balance		$ 1,982		$ 1,494	$ 1,982	$ 1,494	$ 1,312
Balance (in shares)		199,955,000		151,245,000	199,955,000	151,245,000	132,876,000
Issuances of common stock:
Convertible senior subordinated notes (due 2013) exchanges						$ 116
Convertible senior subordinated notes (due 2013) exchanges (in shares)						11,582,000
Acquisition of ViroChem						$ 107
Acquisition of ViroChem (in shares)						10,734,000
Equity offerings						$ 230	$ 155
Equity offerings (in shares)						23,000,000	15,525,000
Convertible senior subordinated notes (due 2013) conversion					$ 14
Convertible senior subordinated notes (due 2013) conversion (in shares)					1,386,000
Benefit plans					$ 20	$ 35	$ 27
Benefit plans (in shares)					2,182,000	3,394,000	2,844,000
Balance	$ 2,016		$ 1,982		$ 2,016	$ 1,982	$ 1,494
Balance (in shares)	203,523,000		199,955,000		203,523,000	199,955,000	151,245,000
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity
Balance		$ 3,784,787		$ 2,281,817	$ 3,784,787	$ 2,281,817	$ 1,856,856
Issuances of common stock:
Convertible senior subordinated notes (due 2013) exchanges						270,776
Acquisition of ViroChem						290,450
Equity offerings						801,155	329,990
Convertible senior subordinated notes (due 2013) conversion					31,551
Benefit plans					39,971	53,867	36,986
Stock-based compensation expense					91,124	86,722	57,985
Balance	$ 3,947,433		$ 3,784,787		3,947,433	3,784,787	2,281,817
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Balance		(640)		3,168	(640)	3,168	881
Unrealized holding gains (losses) on marketable securities					46	(3,178)	3,683
Reclassification adjustment for realized loss on marketable securities included in net loss							(1,242)
Translation adjustments					(473)	(630)	(154)
Issuances of common stock:
Balance	(1,067)		(640)		(1,067)	(640)	3,168
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Balance		$ (2,689,783)		$ (2,047,605)	(2,689,783)	(2,047,605)	(1,587,754)
Net loss					(754,626)	(642,178)	(459,851)
Issuances of common stock:
Balance	$ (3,444,409)		$ (2,689,783)		(3,444,409)	(2,689,783)	(2,047,605)
Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Unrealized holding gains (losses) on marketable securities					46	(3,178)	3,683
Reclassification adjustment for realized loss on marketable securities included in net loss							(1,242)
Translation adjustments					(473)	(630)	(154)
Net loss					(754,626)	(642,178)	(459,851)
Comprehensive loss					$ (755,053)	$ (645,986)	$ (457,564)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Cash flows from operating activities:
Net loss	$ (180,392)	$ (158,644)	$ (754,626)	$ (642,178)	$ (459,851)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense			30,459	30,107	32,196
Stock-based compensation expense			91,124	86,722	57,985
Other non-cash based compensation expense			6,552	6,044	5,027
Intangible asset impairment charges		7,200		7,200
Secured notes (due 2012) discount amortization expense			13,589	3,125
Change in fair value of derivative instruments			41,229	1,847
Change in deferred tax liability				(2,225)
Loss on disposal of property and equipment			39	2,211	11
Realized gain on marketable securities					(633)
Loss on exchanges of convertible senior subordinated notes (due 2013)		5,843		18,137
Other non-cash expenses, net			(31)
Changes in operating assets and liabilities, excluding the effect of an acquisition:
Accounts receivable			(2,923)	13,900	7,831
Prepaid expenses and other current assets			(600)	2,070	(7,331)
Accounts payable			(1,182)	(15,057)	19,010
Accrued expenses and other liabilities			8,182	8,924	58
Accrued restructuring expense			(4,422)	(47)	(1,228)
Accrued interest			3,031	(1,423)	5,349
Deferred revenues			(65,863)	53,057	115,094
Net cash used in operating activities			(635,442)	(427,586)	(226,482)
Cash flows from investing activities:
Purchases of marketable securities			(1,234,719)	(1,186,701)	(755,422)
Sales and maturities of marketable securities			1,284,806	788,263	427,648
Payment for the acquisition of ViroChem, net of cash acquired				(87,422)
Expenditures for property and equipment			(38,054)	(23,496)	(32,180)
Increase in restricted cash			(3,777)	(55)
(Increase) decrease in other assets			(955)	679	(696)
Net cash provided by (used in) investing activities			7,301	(508,732)	(360,650)
Cash flows from financing activities:
Issuances of common stock from employee benefit plans, net			33,434	47,850	31,983
Issuances of common stock from stock offerings, net				801,385	330,145
Issuances of convertible senior subordinated notes, net			391,645		278,607
Issuance of secured notes (due 2012) and sale of potential future milestone payments, net				149,902
Repayment of collaborator development loan (due 2008)					(19,997)
Debt conversion/exchange costs			(22)	(131)
Net cash provided by financing activities			425,057	999,006	620,738
Effect of changes in exchange rates on cash			(377)	(5,145)	(154)
Net (decrease) increase in cash and cash equivalents			(203,461)	57,543	33,452
Cash and cash equivalents-beginning of period			446,658	389,115	355,663
Cash and cash equivalents-end of period	243,197	446,658	243,197	446,658	389,115
Supplemental disclosure of cash flow information:
Cash paid for interest			761	10,248	$ 6,676
Cash paid for taxes
Conversion/exchange of convertible senior subordinated notes (due 2013) for common stock	$ 32,071	$ 255,429	32,071	255,429
Accrued interest offset to additional paid-in capital on conversion/exchange of convertible senior subordinated notes (due 2013)			140	3,355
Unamortized debt issuance costs of converted/exchanged convertible senior subordinated notes (due 2013) offset to additional paid-in capital			$ 624	5,899
Fair value of common stock issued to acquire ViroChem				$ 290,557

The Company	12 Months Ended
The Company	Dec. 31, 2010
The Company
The Company	table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2" /font/p p style="FONT-FAMILY: times"font size="2"bA. The Company /b/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Vertex Pharmaceuticals Incorporated ("Vertex" or the "Company") is in the business of discovering, developing and commercializing small molecule drugs for the treatment of serious diseases. Telaprevir, the Company's lead drug candidate, is an oral hepatitis C protease inhibitor. In November 2010, the Company submitted a new drug application ("NDA") requesting approval to market telaprevir in the United States for the treatment of patients with chronic hepatitis C virus infection. In January 2011, the Company received priority review designation for its telaprevir NDA from the United States Food and Drug Administration (the "FDA"), and the target date for the FDA to complete its review of the telaprevir NDA is Maynbsp;23, 2011. The Company also is developing, among other drug candidates, VX-770, which is being evaluated in a registration program focused on patients with cystic fibrosis who have the G551D mutation in the gene responsible for cystic fibrosis. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company's net loss for 2010 was $754.6nbsp;million, or $3.77 per basic and diluted common share, and the Company expects to incur operating losses at least until it obtains marketing approval and successfully commercializes telaprevir. As of Decembernbsp;31, 2010, the Company had cash, cash equivalents and marketable securities of $1.0nbsp;billion. The Company expects that the Company's current cash, cash equivalents and marketable securities will be sufficient to fund its operations for at least the next twelve months. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Vertex is subject to risks common to companies in its industry including, but not limited to, the dependence on the success of the Company's lead drug candidate, uncertainty about clinical trial outcomes, limited experience in drug development, manufacturing, and sales and marketing, rapid technological change and competition, uncertain protection of proprietary technology, the need to comply with government regulations, share price volatility, uncertainties relating to pharmaceutical pricing and reimbursement, dependence on collaborative relationships and potential product liability. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;On Marchnbsp;12, 2009, Vertex acquired ViroChem Pharmanbsp;Inc. ("ViroChem"). The Company consolidated ViroChem's operating results with those of Vertex beginning on the date of the acquisition. See Notenbsp;P, "Acquisition of ViroChem Pharmanbsp;Inc.," for further information regarding the acquisition. /font/p/td/tr/table

Accrued Expenses and Other Current Liabilities and Other Obligations	12 Months Ended
	Dec. 31, 2010
Accrued Expenses and Other Current Liabilities and Other Obligations
Accrued Expenses and Other Current Liabilities and Other Obligations	table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2" /font/p p style="FONT-FAMILY: times"font size="2"bJ. Accrued Expenses and Other Current Liabilities and Other Obligations /b/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Accrued expenses and other current liabilities consisted of the following at Decembernbsp;31:/font/p div style="PADDING-RIGHT: 0pt; PADDING-LEFT: 0pt; PADDING-BOTTOM: 0pt; MARGIN-LEFT: 20%; WIDTH: 60%; PADDING-TOP: 0pt; POSITION: relative" p style="FONT-FAMILY: times"font size="1"!-- COMMAND=ADD_TABLEWIDTH,"100%" --/font/p !-- User-specified TAGGED TABLE -- div align="center" table cellspacing="0" cellpadding="0" width="100%" border="0" tr style="HEIGHT: 0px"!-- TABLE COLUMN WIDTHS SET -- td style="FONT-FAMILY: times" align="left" width="8"/td td style="FONT-FAMILY: times" align="left"/td td style="FONT-FAMILY: times" width="12"/td td style="FONT-FAMILY: times" align="right" width="6"/td td style="FONT-FAMILY: times" width="42"/td td style="FONT-FAMILY: times" width="12"/td td style="FONT-FAMILY: times" align="right" width="6"/td td style="FONT-FAMILY: times" width="42"/td td style="FONT-FAMILY: times" width="12"/td!-- TABLE COLUMN WIDTHS END --/tr tr style="HEIGHT: 0px" valign="bottom" th style="FONT-FAMILY: times" align="left" colspan="2"font size="1"nbsp;/fontbr //th th style="FONT-FAMILY: times"font size="1"nbsp;/font/th th style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" align="center" colspan="2"font size="1"b2010 /b/font/th th style="FONT-FAMILY: times"font size="1"nbsp;/font/th th style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" align="center" colspan="2"font size="1"b2009 /b/font/th th style="FONT-FAMILY: times"font size="1"nbsp;/font/th/tr tr style="HEIGHT: 0px" valign="bottom" th style="FONT-FAMILY: times" align="left" colspan="2"font size="1"nbsp;/fontbr //th th style="FONT-FAMILY: times"font size="1"nbsp;/font/th th style="FONT-FAMILY: times" align="center" colspan="5"font size="1"b(in thousands)/b/fontbr //th th style="FONT-FAMILY: times"font size="1"nbsp;/font/th/tr tr style="HEIGHT: 0px" valign="top" bgcolor="#CCEEFF" td style="FONT-FAMILY: times" valign="bottom" colspan="2" p style="MARGIN-LEFT: 8pt; TEXT-INDENT: -8pt; FONT-FAMILY: times"font size="1"Research and development contract costs/font/p/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"$/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"58,375/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"$/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"54,912/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td/tr tr style="HEIGHT: 0px" valign="top" bgcolor="white" td style="FONT-FAMILY: times" valign="bottom" colspan="2" p style="MARGIN-LEFT: 8pt; TEXT-INDENT: -8pt; FONT-FAMILY: times"font size="1"Payroll and benefits/font/p/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"52,415/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"45,882/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td/tr tr style="HEIGHT: 0px" valign="top" bgcolor="#CCEEFF" td style="FONT-FAMILY: times" valign="bottom" colspan="2" p style="MARGIN-LEFT: 8pt; TEXT-INDENT: -8pt; FONT-FAMILY: times"font size="1"Professional fees/font/p/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"8,629/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"7,801/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td/tr tr style="HEIGHT: 0px" valign="top" bgcolor="white" td style="FONT-FAMILY: times" valign="bottom" colspan="2" p style="MARGIN-LEFT: 8pt; TEXT-INDENT: -8pt; FONT-FAMILY: times"font size="1"Other/font/p/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"14,995/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"10,158/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td/tr tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top" td style="FONT-FAMILY: times" valign="bottom" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td/tr tr style="HEIGHT: 0px" valign="top" bgcolor="#CCEEFF" td style="FONT-FAMILY: times"font size="0"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" p style="MARGIN-LEFT: 8pt; TEXT-INDENT: -8pt; FONT-FAMILY: times"font size="1"Total/font/p/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"$/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"134,414/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"$/font/td td style="FONT-FAMILY: times" valign="bottom" align="right"font size="1"118,753/font/td td style="FONT-FAMILY: times" valign="bottom"font size="1"nbsp;/font/td/tr tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top" td style="FONT-FAMILY: times" valign="bottom" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td td style="BORDER-BOTTOM: #000000 2.25pt double; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td td style="BORDER-BOTTOM: #000000 2.25pt double; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"nbsp;/td td style="FONT-FAMILY: times" valign="bottom"nbsp;/td/tr/table/div !-- end of user-specified TAGGED TABLE --/div p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;Other obligations of $6.2nbsp;million and $15.2nbsp;million as of Decembernbsp;31, 2010 and 2009, respectively, consisted of the remaining amount of a deposit received from a collaborator for potential future obligations of the Company. /font/p/td/tr/table

Common Stock Offerings	12 Months Ended
Common Stock Offerings	Dec. 31, 2010
Common Stock Offerings
Common Stock Offerings	table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2" /font/p p style="FONT-FAMILY: times"font size="2"bM. Common Stock Offerings/b/font/p p style="FONT-FAMILY: times"font size="2"iFebruary 2008 Offering/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In February 2008, the Company completed an offering 6,900,000 shares of common stock, which were sold at a price of $17.14 per share. This offering resulted in net proceeds of $112.7nbsp;million to the Company. The underwriting discount of $5.3nbsp;million and other expenses of $0.2nbsp;million were recorded as an offset to additional paid-in-capital. /font/p p style="FONT-FAMILY: times"font size="2"iSeptember 2008 Offering/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In September 2008, the Company completed an offering of 8,625,000 shares of common stock, which were sold at a price of $25.50 per share. This offering resulted in $217.4nbsp;million of net proceeds to the Company. The underwriting discount of $2.2nbsp;million and other expenses of $0.3nbsp;million were recorded as an offset to additional paid-in-capital. /font/p p style="FONT-FAMILY: times"font size="2"iFebruary 2009 Offering/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In February 2009, the Company completed an offering of 10,000,000 shares of common stock, which were sold at a price of $32.00 per share. This offering resulted in $313.3nbsp;million of net proceeds to the Company. The underwriting discount of $6.4nbsp;million and other expenses of $0.3nbsp;million were recorded as an offset to additional paid-in capital. /font/p p style="FONT-FAMILY: times"font size="2"iDecember 2009 Offering/i/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;In December 2009, the Company completed an offering of 13,000,000 shares of common stock, which were sold at a price of $38.50 per share. This offering resulted in $488.1nbsp;million of net proceeds to the Company. The underwriting discount of $12.1nbsp;million and other expenses of $0.3nbsp;million were recorded as an offset to additional paid-in capital. /font/p/td/tr/table

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2010
Subsequent Event
Subsequent Event	table style="font-size:10pt; font-family:'Times New Roman',times,serif;" tr td p style="FONT-FAMILY: times"font size="2" /font/p p style="FONT-FAMILY: times"font size="2"bV. Subsequent Event/b/font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;On Januarynbsp;7, 2011, the Company entered into a credit agreement with Bank of America, N.A. as administrative agent and lender. The credit agreement provides for a $100.0nbsp;million revolving credit facility that is initially unsecured./font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The Company may elect that the loans under the credit agreement bear interest at a rate per annum equal to (i)nbsp;LIBOR plus 1.50%, or (ii)nbsp;the rate of interest publicly announced from time to time by Bank of America as its prime rate. The Company may prepay the loans, in whole or in part, in minimum amounts without premium or penalty, other than customary breakage costs with respect to LIBOR borrowings. The Company may borrow, repay and reborrow under the facility until Julynbsp;6, 2012, at which point the facility terminates. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The agreement contains customary representations and warranties, affirmative and negative covenants and events of default, including payment defaults, defaults for breaches of representations and warranties, covenant defaults and cross defaults. The credit agreement also requires that the Company comply with certain financial covenants, including a covenant that requires the Company to maintain at least $400.0nbsp;million in cash, cash equivalents and marketable securities in domestic deposit and securities accounts and a covenant that limits the Company's quarterly net losses. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;The obligations of the lender to make an initial advance under the credit agreement are subject to a number of conditions, including a satisfactory due diligence review of the Company's financial position and business. Also, if, prior to an initial borrowing under the credit agreement, the Company engages in certain investment, acquisition or disposition transactions or prepays indebtedness, such activities could restrict the Company's ability to borrow under the credit agreement./font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;If the Company borrows under the credit agreement, the Company will become subject to certain additional negative covenants, subject to exceptions, restricting or limiting the Company's ability and the ability of the Company's subsidiaries to, among other things, grant liens, make certain investments, incur indebtedness, make certain dispositions and prepay indebtedness. /font/p p style="FONT-FAMILY: times"font size="2"nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;nbsp;If the Company defaults under certain provisions of the credit agreement, including any default of a financial covenant, the loans will become secured by the Company's cash, cash equivalents and marketable securities with a margined value of $100.0nbsp;million. In addition, if an event of default occurs, the interest rate would increase and the administrative agent would be entitled to take various actions, including the acceleration of payment of amounts due under the loan. /font/p/td/tr/table