Exelixis (EXEL) 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 26, 2015	Jun. 27, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	2-Jan-15
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	exel
Entity Registrant Name	EXELIXIS, INC.
Entity Central Index Key	939767
Entity Filer Category	Large Accelerated Filer
Current Fiscal Year End Date	-1
Entity Common Stock, Shares Outstanding		195,895,769
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$665,606,336
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$80,395	$103,978
Short-term investments	63,890	138,475
Short-term restricted cash and investments	12,212	12,213
Trade and other receivables	4,882	3,941
Inventory	2,381	2,890
Prepaid expenses and other current assets	3,481	5,112
Total current assets	167,241	266,609
Long-term investments	81,579	144,299
Long-term restricted cash and investments	4,684	16,897
Property and equipment, net	2,432	4,910
Goodwill	63,684	63,684
Other assets	8,340	6,888
Total assets	327,960	503,287
Current liabilities:
Accounts payable	6,413	9,345
Accrued clinical trial liabilities	41,545	34,958
Accrued compensation and benefits	3,350	12,797
Other accrued liabilities	12,282	13,116
Current portion of convertible notes	98,880	10,000
Current portion of loans payable	381	1,762
Current portion of restructuring	6,426	4,425
Deferred revenue	2,583	1,450
Total current liabilities	171,860	87,853
Long-term portion of convertible notes	182,395	255,147
Long-term portion of loans payable	80,000	80,328
Long-term portion of restructuring	4,365	9,047
Other long-term liabilities	4,169	4,674
Total liabilities	442,789	437,049
Commitments
Stockholders’ (deficit) equity:
Preferred stock, $0.001 par value, 10,000,000 shares authorized and no shares issued	0	0
Common stock, $0.001 par value; 400,000,000 shares authorized; issued and outstanding: 195,895,769 and 184,533,651 shares at December 31, 2014 and 2013, respectively	196	184
Additional paid-in capital	1,652,400	1,564,670
Accumulated other comprehensive (loss) income	-121	146
Accumulated deficit	-1,767,304	-1,498,762
Total stockholders’ equity	-114,829	66,238
Total liabilities and stockholders’ equity	$327,960	$503,287

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	195,895,769	184,533,651
Common stock, shares outstanding	195,895,769	184,533,651

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Net product revenues	$25,111	$15,017	$0
License and contract revenues	0	16,321	47,450
Total revenues	25,111	31,338	47,450
Operating expenses:
Cost of goods sold	2,043	1,118	0
Research and development	189,101	178,763	128,878
Selling, general and administrative	50,829	50,958	31,837
Restructuring charges	7,596	1,231	9,171
Total operating expenses	249,569	232,070	169,886
Loss from operations	-224,458	-200,732	-122,436
Other income (expense), net:
Interest income and other, net	4,341	1,223	1,986
Interest expense	-48,607	-45,347	-27,088
Total other income (expense), net	-44,266	-44,124	-25,102
Loss before income taxes	-268,724	-244,856	-147,538
Income tax (benefit) provision	-182	-96	107
Net (loss) income	($268,542)	($244,760)	($147,645)
Net loss per share, basic and diluted (in dollars per share)	($1.38)	($1.33)	($0.92)
Shares used in computing basic and diluted net loss per share amounts	194,299	184,062	160,138

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net loss	($268,542)		($244,760)		($147,645)
Other comprehensive (loss) income, net of tax of $0, $106 and $0	-267	[1]	238	[1]	46	[1]
Comprehensive loss	($268,809)		($244,522)		($147,599)
[1]	Other comprehensive (loss) income consisted solely of unrealized gains or losses on available for sale securities arising during the periods presented. There were no reclassification adjustments to net loss resulting from realized gains or losses on the sale of securities.

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Loss (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Other comprehensive income (loss), tax	$0	($106)	$0

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (Deficit) (USD $)	Total		Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Accumulated Deficit [Member]
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2011	$90,632		$135	$1,196,992	($138)	($1,106,357)
Balance, shares at Dec. 31, 2011			135,563,735
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-147,645					-147,645
Other comprehensive (loss) income	46	[1]			46
Issuance of common stock under stock plans, shares			983,478
Issuance of common stock under stock plans	2,822		1	2,821
Sale of shares of common stock, shares			47,150,000
Sale of shares of common stock	203,961		47	203,914
Equity component of convertible debt issued, net	137,785			137,785
Stock-based compensation expense	8,833			8,833
Balance at Dec. 31, 2012	296,434		183	1,550,345	-92	-1,254,002
Balance, shares at Dec. 31, 2012			183,697,213
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-244,760					-244,760
Other comprehensive (loss) income	238	[1]			238
Issuance of common stock under stock plans, shares			836,438
Issuance of common stock under stock plans	2,295		1	2,294
Stock-based compensation expense	12,031			12,031
Balance at Dec. 31, 2013	66,238		184	1,564,670	146	-1,498,762
Balance, shares at Dec. 31, 2013	184,533,651		184,533,651
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-268,542					-268,542
Other comprehensive (loss) income	-267	[1]			-267
Issuance of common stock under stock plans, shares			1,362,118
Issuance of common stock under stock plans	2,093		2	2,091
Sale of shares of common stock, shares			10,000,000
Sale of shares of common stock	75,643		10	75,633
Stock-based compensation expense	10,006			10,006
Balance at Dec. 31, 2014	($114,829)		$196	$1,652,400	($121)	($1,767,304)
Balance, shares at Dec. 31, 2014	195,895,769		195,895,769
[1]	Other comprehensive (loss) income consisted solely of unrealized gains or losses on available for sale securities arising during the periods presented. There were no reclassification adjustments to net loss resulting from realized gains or losses on the sale of securities.

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net (loss) income	($268,542)	($244,760)	($147,645)
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	2,391	3,147	5,513
Stock-based compensation expense	10,006	12,031	8,833
Accretion of debt discount	29,534	26,290	14,752
Gain on sale of businesses	-838	0	0
Changes in the fair value of warrants	-1,840	0	0
Other	4,161	6,787	4,039
Changes in assets and liabilities:
Trade and other receivables	-941	-1,190	27,038
Inventory	509	-2,890	0
Prepaid expenses and other current assets	1,526	1,034	-1,764
Other assets	-2,149	0	-1,966
Accounts payable and other accrued liabilities	-13,213	8,691	5,149
Clinical trial liability	6,587	14,398	1,169
Restructuring liability	-2,302	-5,750	5,244
Deferred revenue	1,133	-14,871	-41,920
Other long-term liabilities	-1,427	-1,690	-1,588
Net cash used in operating activities	-235,405	-198,773	-123,146
Cash flows from investing activities:
Purchases of property and equipment	-474	-2,171	-2,717
Proceeds from sale of property and equipment	392	143	1,943
Proceeds from sale of business	838	0	0
Proceeds from maturities of restricted cash and investments	20,354	17,268	5,499
Purchase of restricted cash and investments	-8,143	-6,085	-41,485
Proceeds from maturities of investments	252,891	325,171	310,765
Purchases of investments	-119,528	-189,975	-533,475
Net cash provided by (used in) investing activities	146,330	144,351	-259,470
Cash flows from financing activities:
Proceeds from issuance of common stock, net	75,643	0	203,479
Proceeds from exercise of stock options and warrants	120	72	929
Proceeds from employee stock purchase plan	1,438	1,429	1,217
Proceeds from debt issuance, net	0	0	277,673
Principal payments on debt	-11,709	-13,170	-4,870
Net cash provided by (used in) financing activities	65,492	-11,669	478,428
Net (decrease) increase in cash and cash equivalents	-23,583	-66,091	95,812
Cash and cash equivalents at beginning of year	103,978	170,069	74,257
Cash and cash equivalents at end of year	80,395	103,978	170,069
Supplemental cash flow disclosure:
Cash paid for interest	19,109	19,160	6,982
Cash paid for taxes	60	0	1,118
Non-cash financing activity:
Issuance of warrants in connection with amendment to convertible notes	$2,762	$0	$0

Organization_And_Summary_Of_Si

Organization And Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization And Summary Of Significant Accounting Policies	ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Organization
	Exelixis, Inc. (“Exelixis,” “we,” “our” or “us”) is a biopharmaceutical company committed to developing small molecule therapies for the treatment of cancer. We were incorporated in Delaware in November 1994 as Exelixis Pharmaceuticals, Inc. and we changed our name to Exelixis, Inc. in February 2000. Our two most advanced assets are cabozantinib, our wholly-owned inhibitor of multiple receptor tyrosine kinases, and cobimetinib, a potent, highly selective inhibitor of MEK, a serine/threonine kinase, which we out-licensed to Genentech (a member of the Roche Group) (“Genentech”).
	Our development and commercialization efforts are focused primarily on cabozantinib. We are evaluating cabozantinib in a broad development program comprising over forty-five clinical trials, across multiple indications, including two ongoing phase 3 pivotal trials focusing on metastatic renal cell carcinoma (“mRCC”), and advanced hepatocellular carcinoma (“HCC”).
	Cabozantinib was approved by the United States Food and Drug Administration, (“FDA”), on November 29, 2012, for the treatment of progressive, metastatic medullary thyroid cancer (“MTC”) in the United States under the brand name COMETRIQ(R). COMETRIQ became commercially available in the United States in January 2013. In March 2014, the European Commission granted cabozantinib conditional marketing authorization for the treatment of adult patients with progressive, unresectable locally advanced or metastatic MTC, also under the brand name COMETRIQ.
	Our second most advanced oncology asset, cobimetinib, is being evaluated by Genentech in a broad development program, including coBRIM, a phase 3 pivotal trial evaluating cobimetinib in combination with vemurafenib in previously untreated patients with unresectable locally advanced or metastatic melanoma harboring a BRAF V600 mutation. Roche has completed the Marketing Authorization Application (“MAA”), for cobimetinib in combination with vemurafenib in the European Union. In the United States, Genentech filed its New Drug Application (“NDA”) in December 2014.
	Basis of Consolidation
	The consolidated financial statements include the accounts of Exelixis and those of our wholly-owned subsidiaries, including Exelixis International (Bermuda) Ltd. (“Exelixis Bermuda”). Effective July 2013, Exelixis engaged in intercompany transactions whereby Exelixis Bermuda acquired the existing and future intellectual property rights to exploit cabozantinib in jurisdictions outside of the United States. Exelixis Bermuda’s functional currency is the U.S. Dollar. All intercompany balances and transactions have been eliminated.
	Basis of Presentation
	Exelixis has adopted a 52- or 53-week fiscal year that generally ends on the Friday closest to December 31st. Fiscal year 2012, a 52-week year, ended on December 28, 2012, fiscal year 2013, a 52-week year, ended on December 27, 2013, fiscal year 2014, a 53-week year, ended on January 2, 2015 and fiscal year 2015, a 52-week year, will end on January 1, 2016. For convenience, references in this report as of and for the fiscal years ended December 28, 2012, December 27, 2013 and January 2, 2015, are indicated on a calendar year basis, ended December 31, 2012, 2013 and 2014, respectively. The quarter ended January 2, 2015 is a 14-week fiscal quarter; all other interim periods presented are 13-week fiscal quarters.
	Segment Information
	We operate as a single reportable segment.
	Use of Estimates
	The preparation of our consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make judgments. The preparation of our consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, including for deductions from revenues (such as rebates, chargebacks, sales returns and sales allowances), recoverability of inventory, certain accrued liabilities including clinical trial accruals and restructuring liabilities, the valuation of the debt and equity components of our convertible debt at issuance, valuation of warrants, and share-based compensation. We base our estimates on historical experience and on various other market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates.
	Need to Access Additional Capital
	We have incurred annual net losses since inception through the year ended December 31, 2014, with the exception of the 2011 fiscal year. We anticipate net losses and negative operating cash flow for the foreseeable future. For the year ended December 31, 2014, we had a net loss of $268.5 million and as of December 31, 2014, we had an accumulated deficit of $1.8 billion. These losses have had, and will continue to have, an adverse effect on our stockholders’ (deficit) equity and working capital. Because of the numerous risks and uncertainties associated with developing drugs, we are unable to predict the extent of any future losses or whether or when we will become profitable, if at all. Our research and development expenditures and general and administrative expenses have exceeded our revenues for each year other than 2011, and we expect to spend significant additional amounts to fund the continued development and commercialization of cabozantinib. As a result, we expect to continue to incur substantial operating expenses, and, consequently, we will need to generate significant additional revenues to achieve future profitability.
	We commercially launched COMETRIQ for the treatment of progressive, metastatic MTC in the United States in late January 2013 and from the commercial launch through December 31, 2014, we have generated $40.1 million in net revenues from the sale of COMETRIQ. Other than revenues from COMETRIQ, we have derived substantially all of our revenues since inception from collaborative research and development agreements which depend on research funding, the achievement of milestones, and royalties we earn from any future products developed from the collaborative research.
	The amount of our net losses will depend, in part, on the rate of growth, if any, in our sales of COMETRIQ, our share of the net profits and losses for the commercialization for cobimetinib in the U.S., if any, and receipt of royalties from cobimetinib sales outside the U.S., if any, partnering activities for cabozantinib, other license and contract revenues and the level of expenses, primarily with respect to development and commercialization activities for cabozantinib.
	As of December 31, 2014, we had $242.8 million in cash and investments, which included $144.3 million available for operations, $12.2 million of short-term restricted investments available for public debt service obligations, $81.6 million of compensating balance investments that we are required to maintain on deposit with Silicon Valley Bank, and $4.7 million of long-term restricted investments. Taking into account our cost saving measures, including the planned effects of the 2014 Restructuring that we initiated on September 2, 2014, and the expected extension of the maturity date to July 1, 2018 of $100.0 million principal amount of the Deerfield Notes, classified within current liabilities on our Consolidated Balance Sheet as of December 31, 2014, we anticipate that our current cash and cash equivalents, and short-term investments available for operations, and product revenues will enable us to maintain our operations through at least December 31, 2015. While a forecast of future events is inherently uncertain, our ability to sustain our business operations beyond the next twelve months is highly dependent on the commercial success of COMETRIQ and the revenues we generate as well as the commercial success of cobimetinib and our share of related net profits and losses, and royalties under our collaboration with Genentech. Consistent with the actions we have taken in the past, we will prioritize necessary and appropriate steps to ensure the continued operation of our business and preservation of the value of our assets beyond the next twelve months, including but not limited to actions such as further reductions in headcount, additional consolidation of administrative functions, asset sales and additional curtailment of our development activities. However, our future capital requirements will be substantial, and we may need to access additional capital in the future. We may seek to access additional capital to support future operations through licensing, partnering or other strategic collaborative arrangements; and, we may pursue the issuance of equity or debt securities or external borrowings. It is unclear when any such transactions will occur, on satisfactory terms or at all. Our ability to raise additional capital in the equity and debt markets, should we choose to do so, is dependent on a number of factors, including, but not limited to, the market demand for our common stock, which itself is subject to a number of pharmaceutical development and business risks and uncertainties, as well as the uncertainty that we would be able to raise such additional capital at a price or on terms that are favorable to us.
	Cash and Investments
	We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents include investments in high-grade, short-term money market funds, commercial paper and municipal securities, which are subject to minimal credit and market risk.
	We have designated all investments as available-for-sale and therefore, such investments are reported at fair value, with unrealized gains and losses recorded in accumulated other comprehensive (loss) income. For securities sold prior to maturity, the cost of securities sold is based on the specific identification method. Realized gains and losses on the sale of investments are recorded in interest and other income, net.
	We classify those investments we do not require for use in current operations that mature in more than 12 months as Long-term investments on our Consolidated Balance Sheets. Additionally, those investments that collateralize loan balances with terms that extend 12 months or longer were classified as long-term investments even if the investment’s remaining term to maturity was one year or less; they are not restricted to withdrawal.
	All of our investments are subject to a quarterly impairment review. We recognize an impairment charge when a decline in the fair value of its investments below the cost basis is judged to be other-than-temporary. Factors considered in determining whether a loss is temporary included the length of time and extent to which the investments fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, extent of the loss related to credit of the issuer, the expected cash flows from the security, our intent to sell the security and whether or not we will be required to sell the security before the recovery of its amortized cost. During the years ended December 31, 2014, 2013, and 2012, we did not record any significant other-than-temporary impairment charges on our available-for-sale securities.
	Fair Value Measurements
	Fair value reflects the amounts that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We disclose the fair value of financial instruments for assets and liabilities for which the value is practicable to estimate. For those financial instruments measured and recorded at fair value on a recurring basis, we also provide fair value hierarchy information in these Notes to Consolidated Financial Statements. The fair value hierarchy has the following three levels:
	Level 1 – quoted prices (unadjusted) in active markets for identical assets and liabilities that the reporting entity can access at the measurement date.
	Level 2 – observable inputs, other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly. These inputs include using prices from independent pricing services based on quoted prices in active markets for similar instruments or on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets.
	Level 3—unobservable inputs.
	A review of the fair value hierarchy classification is conducted on a quarterly basis. Changes in the observability of valuation inputs may result in a reclassification of levels for certain investments within the fair value hierarchy.
	Inventory
	Inventory is valued at the lower of cost or net realizable value. We determine the cost of inventory using the standard-cost method, which approximates actual cost based on a first-in, first-out method. We analyze our inventory levels quarterly and write down inventory subject to expiry in excess of expected requirements, or has a cost basis in excess of its expected net realizable value. The related costs are recognized as cost of goods sold in the Consolidated Statements of Operations.
	We analyze our estimated production levels for the following twelve month period quarterly and reclassify inventory we do not expect to use within the next twelve months in Other assets in the Consolidated Balance Sheets.
	We consider regulatory approval of product candidates to be uncertain and product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained. As such, the manufacturing costs for product candidates incurred prior to regulatory approval were not capitalized as inventory but were expensed as research and development costs. When regulatory approval is obtained, we begin capitalization of inventory related costs.
	Property and Equipment
	Property and equipment are recorded at cost and depreciated using the straight-line method over the following estimated useful lives:
	Equipment and furniture	5 years
	Computer equipment and software	3 years
	Leasehold improvements	Shorter of lease life or 7 years
	Capitalized software includes certain internal use computer software costs.
	Repairs and maintenance costs are charged to expense as incurred.
	Goodwill
	Goodwill amounts have been recorded as the excess purchase price over tangible assets, liabilities and intangible assets acquired based on their estimated fair value, by applying the purchase method. Goodwill is not subject to amortization. We evaluate goodwill for impairment on an annual basis and on an interim basis if events or changes in circumstances between annual impairment tests indicate that the asset might be impaired. When evaluating goodwill for impairment we must determine the reporting units that exist within Exelixis. We have determined that we have one reporting unit as of December 31, 2014 and 2013.
	Long-Lived Assets
	Long-lived assets include property and equipment. The carrying value of our long-lived assets is reviewed for impairment whenever events or changes in circumstances indicate that the asset may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount.
	Revenue Recognition
	We recognize revenue from the sale of COMETRIQ and from license fees, milestones and contingent payments earned on research and collaboration arrangements.
	License and Contract Revenues
	License, research commitment and other non-refundable payments received in connection with research collaboration agreements are deferred and recognized on a straight-line basis over the period of continuing involvement, generally the research term specified in the agreement. Contract research revenues are recognized as services are performed pursuant to the terms of the agreements. Any amounts received in advance of performance are recorded as deferred revenue. Payments are not refundable if research is not successful. License fees are classified as license revenues in our Consolidated Statements of Operations.
	We enter into corporate collaborations under which we may obtain upfront license fees, research funding, contingent, milestone and royalty payments. Our deliverables under these arrangements typically consist of intellectual property rights and research and development services. We evaluate whether the delivered elements under these arrangements have value to our collaboration partner on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered item exists. If we determine that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. A delivered item or items that do not qualify as a separate unit of accounting within the arrangement shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. A delivered item or items that do not have stand-alone value to our collaboration partner shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. For a combined unit of accounting, non-refundable upfront fees and milestones are recognized in a manner consistent with the final deliverable, which has generally been ratably over the period of the research and development obligation.
	Contingency payments (received upon the achievement of certain events by our collaborators) and milestone payments (received upon the achievement of certain events by us) are non-refundable and recognized as revenues over the period of the research arrangement. This typically results in a portion of the payments being recognized at the date the contingency or milestone is achieved, which portion is equal to the applicable percentage of the research term that has elapsed at the date of achievement, and the balance being recognized over the remaining research term of the agreement. In certain situations, we may receive contingent payments after the end of our period of continued involvement. In such circumstances, we would recognize 100% of the contingent revenues when the contingency is achieved. Contingency and milestones payments, when recognized as revenue, are classified as contract revenues in our Consolidated Statements of Operations.
	Revenues and expenses from collaborations that are not co-development agreements are recorded as contract revenues or research and development expenses in the period incurred.
	Net Product Revenues
	We recognize revenue when it is both realized or realizable and earned, meaning persuasive evidence of an arrangement exists, delivery has occurred, title has transferred, the price is fixed or determinable, there are no remaining customer acceptance requirements, and collectability of the resulting receivable is reasonably assured. For product sales in the United States, this generally occurs upon shipment of the product to the patient by our distributor. For product sales in Europe, this occurs when our European distribution partner has accepted the product.
	We sell our product, COMETRIQ, in the United States to a specialty pharmacy that benefits from customer incentives and has a right of return. We have a limited sales history and cannot reliably estimate expected returns of the product nor the discounts and rebates due to payers at the time of shipment to the specialty pharmacy. Accordingly, upon shipment to the specialty pharmacy, we record deferred revenue on our Consolidated Balance Sheets. We recognize revenue when the specialty pharmacy provides the product to a patient based on the fulfillment of a prescription. We record revenue using an analysis of prescription data from our specialty pharmacy to ascertain the date of shipment and the payer mix. This approach is frequently referred to as the “sell-through” revenue recognition model. Once the prescription has been provided to the patient, it is not subject to return unless the product is damaged.
	Product sales to our European distribution partner are not subject to rights of return or discounts and allowances. We record revenue at the time our European distribution partner has accepted the product, a method also known as the “sell-in” revenue recognition model.
	Product Sales Discounts and Allowances
	We calculate gross product revenues based on the price that we charge our United States specialty pharmacy and our European distribution partner. We estimate our domestic net product revenues by deducting from our gross product revenues (a) trade allowances, such as discounts for prompt payment, (b) estimated government rebates and chargebacks, and (c) estimated costs of patient assistance programs. We initially record estimates for these deductions at the time we recognize the gross revenue. We update our estimates on a recurring basis as new information becomes available.
	Customer Credits: The United States specialty pharmacy receives a discount of 2% for prompt payment. We expect this specialty pharmacy will earn 100% of its prompt payment discounts and, therefore, we deduct the full amount of these discounts from total product sales when revenues are recognized.
	Mandated Rebates: Allowances for rebates include mandated discounts under the Medicaid Drug Rebate Program and other government programs. Rebate amounts owed after the final dispensing of the product to a benefit plan participant are based upon contractual agreements or legal requirements with public sector benefit providers, such as Medicaid. The allowance for rebates is based on statutory discount rates and expected utilization. Our estimates for the expected utilization of rebates are based on customer and payer data received from the United States specialty pharmacy. Rebates are generally invoiced by the payer and paid in arrears, such that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s shipments to patients, plus an accrual balance for known prior quarter’s unpaid rebates. If actual future rebates vary from estimates, we may need to adjust our accruals, which would affect net revenue in the period of adjustment.
	Chargebacks: Chargebacks are discounts that occur when contracted customers purchase directly from a specialty pharmacy. Contracted customers, which currently consist primarily of Public Health Service institutions, non-profit clinics, and Federal government entities purchasing via the Federal Supply Schedule, generally purchase the product at a discounted price. The United States specialty pharmacy, in turn, charges back to us the difference between the price initially paid by the specialty pharmacy and the discounted price paid to the specialty pharmacy by the customer. The allowance for chargebacks is based on sales to contracted customers.
	Medicare Part D Coverage Gap: In the United States, the Medicare Part D prescription drug benefit mandates manufacturers to fund 50% of the Medicare Part D insurance coverage gap for prescription drugs sold to eligible patients. Our estimates for expected Medicare Part D coverage gap are based in part on third party market research data and on customer and payer data received from the United States specialty pharmacy. Funding of the coverage gap is invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter's shipments to patients, plus an accrual balance for prior sales. If actual future funding varies from estimates, we may need to adjust our accruals, which would affect net revenue in the period of adjustment.
	Co-payment Assistance: Patients who have commercial insurance and meet certain eligibility requirements may receive co-payment assistance. We accrue a liability for co-payment assistance based on actual program participation and estimates of program redemption using customer data provided by our United States specialty pharmacy.
	Our European distribution partner is entitled to receive a project management fee based upon the achievement of a pre-specified revenue goal which, when deemed probable, is ratably accrued as a reduction to gross revenue.
Patient Assistance Program
We provide COMETRIQ at no cost to eligible patients who have no insurance and meet certain financial and clinical criteria through our Patient Assistance Program (“PAP”). We record the cost of the product as a selling, general and administrative expense at the time the product is designated as PAP inventory.
Cost of Goods Sold
Cost of goods sold is related to our product revenues and consists primarily of a 3% royalty and indirect labor costs, and to a lesser extent, the cost of manufacturing and other third party logistics costs of our product. A significant portion of the manufacturing costs for product sales were incurred prior to regulatory approval of COMETRIQ for the treatment of progressive, metastatic MTC and, therefore, were expensed as research and development costs when those costs were incurred, rather than capitalized as inventory.
In accordance with our product development and commercialization agreement with GlaxoSmithKline, we are required to pay GlaxoSmithKline a 3% royalty on the Net Sales of any product incorporating cabozantinib, including COMETRIQ. Net Sales is defined in the product development and commercialization agreement generally as the gross invoiced sales price less customer credits, rebates, chargebacks, shipping costs, customs duties, and sales tax and other similar tax payments we are required to make.
Research and Development Expenses
Research and development costs are expensed as incurred and include costs associated with research performed pursuant to collaborative agreements. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research activities on our behalf.
Substantial portions of our preclinical studies and all of our clinical trials have been executed with support from third-party contract research organizations (“CROs”) and other vendors. We accrue expenses for preclinical studies performed by our vendors based on certain estimates over the term of the service period and adjust our estimates as required. We accrue expenses for clinical trial activities performed by CROs based upon the estimated amount of work completed on each trial. For clinical trial expenses, the significant factors used in estimating accruals include the number of patients enrolled, the number of active clinical sites, and the duration for which the patients will be enrolled in the trial. We monitor patient enrollment levels and related activities to the extent possible through internal reviews, correspondence with CROs and review of contractual terms. We base our estimates on the best information available at the time. However, additional information may become available to us which may allow us to make a more accurate estimate in future periods. In this event, we may be required to record adjustments to research and development expenses in future periods when the actual level of activity becomes more certain. Such increases or decreases in cost are generally considered to be changes in estimates and will be reflected in research and development expenses in the period first known. For example, during the years ended December 31, 2013 and 2012, we recorded a reduction related to prior periods of approximately $0.8 million, and $2.7 million, respectively, to our accrued clinical trial liabilities and research and development expenses primarily related to our phase 2 and phase 3 clinical trials for cabozantinib. There were no such significant adjustments during the year ended December 31, 2014.
Net (Loss) Income Per Share
Basic net (loss) income per share is computed by dividing the net (loss) income for the period by the weighted average number of shares of common stock outstanding during the period. Diluted net (loss) income per share gives effect to potential incremental common shares issuable upon the exercise of stock options and warrants, and shares issuable pursuant to restricted stock units (“RSUs”) (calculated based on the treasury stock method), and upon conversion of our convertible debt (calculated using an as-if-converted method) as long as such shares are not anti-dilutive. The calculation of diluted loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of such securities are dilutive to loss per share for the period, adjustments to net loss used in the calculation are required to remove the change in fair value of the warrants for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares.
Foreign Currency Translation and Remeasurement
Monetary assets and liabilities denominated in currencies other than the functional currency are remeasured using exchange rates in effect at the end of the period and related gains or losses are recorded in interest income and other, net. Gains and losses on the remeasurement of monetary assets and liabilities were not material for any of the years presented. We do not have any nonmonetary assets or liabilities denominated in currencies other than the U.S. dollar.
Stock-Based Compensation
Stock-based compensation expense for all stock-based compensation awards is based on the grant date fair value estimated using the Black-Scholes Merton option pricing model. Because there is a market for options on our common stock, we have considered implied volatilities as well as our historical realized volatilities when developing an estimate of expected volatility. We estimate the term using historical data and peer data. We recognize compensation expense on a straight-line basis over the requisite service period. Compensation expense relating to awards subject to performance conditions is recognized if it is probable that the performance goals will be achieved. The probability of achievement is assessed on a quarterly basis. The total number of awards expected to vest is adjusted for estimated forfeitures. We have elected to use the simplified method to calculate the beginning pool of excess tax benefits.
Recently Adopted Accounting Pronouncements
In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 supersedes the revenue recognition requirements of FASB Accounting Standards Codification (“ASC”) Topic 605, Revenue Recognition and most industry-specific guidance throughout the Accounting Standards Codification, resulting in the creation of FASB ASC Topic 606, Revenue from Contracts with Customers. ASU 2014-09 requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. Adoption will be permitted using either a retrospective or modified retrospective approach, and is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is not permitted. We are currently evaluating the impact of adopting this ASU, inclusive of available transitional methods on our consolidated financial statements and related disclosures.
In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (“ASU 2014-15”). ASU 2014-15 provides guidance on management’s responsibility in evaluating whether there are conditions or events that raise substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued, and about related footnote disclosures. ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. We are currently evaluating the impact of adopting ASU 2014-15 and its related disclosures.

Research_And_Collaboration_Agr

Research And Collaboration Agreements	12 Months Ended
	Dec. 31, 2014
Research And Collaboration Agreements [Abstract]
Research And Collaboration Agreements	RESEARCH AND COLLABORATION AGREEMENTS
	Cobimetinib Collaboration
	In December 2006, we entered into a worldwide co-development agreement with Genentech for the development and commercialization of cobimetinib. Exelixis discovered cobimetinib internally and advanced the compound to investigational new drug (“IND”), status.
	Genentech paid upfront and milestone payments of $25.0 million in December 2006 and $15.0 million in January 2007 upon signing of the co-development agreement and with the submission of the IND for cobimetinib. Under the terms of the agreement, we were responsible for developing cobimetinib through the determination of the maximum-tolerated dose (“MTD”) in a phase 1 clinical trial, and Genentech had the option to co-develop cobimetinib, which Genentech could exercise after receipt of certain phase 1 data from us. In March 2008, Genentech exercised its option, triggering a payment to us of $3.0 million, which we received in April 2008. After MTD was determined, we granted to Genentech an exclusive worldwide revenue-bearing license to cobimetinib in March 2009, at which point Genentech became responsible for completing the phase 1 clinical trial and subsequent clinical development. We received an additional $7.0 million payment in March 2010.
	On December 15, 2014, Genentech completed the filing of its NDA with the FDA for cobimetinib. FDA has granted priority review to the NDA, with a PDUFA date of August 11, 2015. Priority Review is granted to a pharmaceutical product that, if approved, would meet an unmet medical need for a serious and life-threatening condition. Cobimetinib previously received Fast Track designation from the FDA.
	Under the terms of our agreement with Genentech, we are entitled to an initial equal share of U.S. profits and losses for cobimetinib, with our share decreasing as sales increase, and we will share equally in the U.S. marketing and commercialization costs. The profit share has multiple tiers--we are entitled to 50% of profits from the first $200 million of U.S. actual sales, decreasing to 30% of profits from U.S. actual sales in excess of $400 million. We are entitled to low double-digit royalties on ex-U.S. net sales. In November 2013, we exercised our option to co-promote in the U.S. We will provide up to 25% of the total sales force for cobimetinib in the U.S. if commercialized, and will call on customers and otherwise engage in promotional activities using that sales force, consistent with the terms of the co-development agreement and a co-promotion agreement to be entered into by the parties. If Genentech terminates the co-development agreement without cause, all licenses that were granted to Genentech under the agreement terminate and revert to us. Additionally, we would receive, subject to certain conditions, licenses from Genentech to research, develop and commercialize reverted product candidates.
	We did not any recognize any revenue under our current agreement with Genentech during the three years ended December 31, 2014.
	Other Collaborations
	We have established collaborations with other leading pharmaceutical and biotechnology companies, including GlaxoSmithKline, Bristol-Myers Squibb Company (“Bristol-Myers Squibb”), Sanofi, Merck (known as MSD outside of the United States and Canada) and Daiichi Sankyo Company Limited (“Daiichi Sankyo”), for various compounds and programs in our portfolio. Pursuant to these collaborations, we have fully out-licensed compounds or programs to a partner for further development and commercialization. We have no further development cost obligations under our collaborations and may be entitled to receive milestones and royalties, or in the case of cobimetinib, a share of profits (or losses) from commercialization.
	With respect to these partnered compounds, we are eligible to receive potential contingent payments under our collaborations totaling approximately $2.3 billion in the aggregate on a non-risk adjusted basis, of which approximately 10% are related to clinical development milestones, approximately 42% are related to regulatory milestones and approximately 48% are related to commercial milestones, all to be achieved by the various licensees which may not be paid, if at all, until certain conditions are met.
	Bristol-Myers Squibb
	ROR Collaboration Agreement
	In October 2010, we entered into a worldwide collaboration with Bristol-Myers Squibb pursuant to which each party granted to the other certain intellectual property licenses to enable the parties to discover, optimize and characterize ROR antagonists that may subsequently be developed and commercialized by Bristol-Myers Squibb. In November 2010 we received a nonrefundable upfront cash payment of $5.0 million from Bristol-Myers Squibb. Additionally, for each product developed by Bristol-Myers Squibb under the collaboration, we will be eligible to receive payments upon the achievement by Bristol-Myers Squibb of development and regulatory milestones of up to $252.5 million in the aggregate and commercialization milestones of up to $150.0 million in the aggregate, as well as royalties on commercial sales of any such products. The collaboration agreement was amended and restated in April 2011 in connection with an assignment of patents to a wholly-owned subsidiary.
	Under the terms of the collaboration agreement, we were responsible for activities related to the discovery, optimization and characterization of the ROR antagonists during the collaborative research period. In July 2011, we earned a $2.5 million milestone payment for achieving certain lead optimization criteria. The collaborative research period began on October 8, 2010 and ended on July 8, 2013. Since the end of the collaborative research period, Bristol-Myers Squibb has and will continue to have sole responsibility for any further research, development, manufacture and commercialization of products developed under the collaboration and will bear all costs and expenses associated with those activities.
	Bristol-Myers Squibb may, at any time, terminate the collaboration agreement upon certain prior notice to us on a product-by-product and country-by-country basis. In addition, either party may terminate the agreement for the other party’s uncured material breach. In the event of termination by Bristol-Myers Squibb at will or by us for Bristol-Myers Squibb’s uncured material breach, the license granted to Bristol-Myers Squibb would terminate, the right to such product would revert to us and we would receive a royalty-bearing license for late-stage reverted compounds and a royalty-free license for early-stage reverted compounds from Bristol-Myers Squibb to develop and commercialize such product in the related country. In the event of termination by Bristol-Myers Squibb for our uncured material breach, Bristol-Myers Squibb would retain the right to such product, subject to continued payment of milestones and royalties.
	We recognized license and contract revenues of $1.5 million and $2.9 million during the years ended December 31, 2013 and 2012, respectively, under our ROR collaboration agreement with Bristol-Myers Squibb. We recognized no such revenue during the year ended December 31, 2014.
	LXR Collaboration Agreement
	In December 2005, we entered into a collaboration agreement with Bristol-Myers Squibb for the discovery, development and commercialization of novel therapies targeted against LXR, a nuclear hormone receptor implicated in a variety of cardiovascular and metabolic disorders. This agreement became effective in January 2006, at which time we granted Bristol-Myers Squibb an exclusive worldwide license with respect to certain intellectual property primarily relating to compounds that modulate LXR, including BMS-852927 (XL041). During the research term, we jointly identified drug candidates with Bristol-Myers Squibb that were ready for IND-enabling studies. After the selection of a drug candidate for further clinical development by Bristol-Myers Squibb, Bristol-Myers Squibb agreed to be solely responsible for further preclinical development as well as clinical development, regulatory, manufacturing and sales/marketing activities for the selected drug candidate. We do not have rights to reacquire the drug candidates selected by Bristol-Myers Squibb. The research term expired in January 2010 and we transferred the technology to Bristol-Myers Squibb in 2011 to enable it to continue the LXR program. BMS has terminated development of XL041 and we have been advised that BMS is continuing additional preclinical research on the program. The collaboration agreement was amended and restated in April 2011 in connection with an assignment of patents to a wholly-owned subsidiary.
	Under the collaboration agreement, Bristol-Myers Squibb paid us a nonrefundable upfront cash payment in the amount of $17.5 million and was obligated to provide research and development funding of $10.0 million per year for an initial research period of two years. In September 2007, the collaboration was extended at Bristol-Myers Squibb’s request through January 12, 2009, and in November 2008, the collaboration was further extended at Bristol-Myers Squibb’s request through January 12, 2010. Under the collaboration agreement, Bristol-Myers Squibb is required to pay us contingent amounts associated with development and regulatory milestones of up to $138.0 million per product for up to two products from the collaboration. In addition, we are also entitled to receive payments associated with sales milestones of up to $225.0 million and royalties on sales of any products commercialized under the collaboration. In connection with the extension of the collaboration through January 2009 and subsequently through January 2010, Bristol-Myers Squibb paid us additional research funding of approximately $7.7 million and approximately $5.8 million, respectively. In December 2007, we received $5.0 million in connection with the achievement by Bristol-Myers Squibb, of a development milestone with respect to BMS-852927 (XL041).
	We did not any recognize any revenue under our LXR collaboration agreement with Bristol-Myers Squibb during the three years ended December 31, 2014.
	Terminated Agreements
	During 2013, a number of additional license and collaboration agreements with Bristol-Myers Squibb were terminated or concluded, including a October 2010 license agreement for our small-molecule TGR5 agonist program and a January 2007 agreement to discover, develop and commercialize novel targeted therapies for the treatment of cancer. As a result of the termination, Bristol-Myers Squibb’s license relating to cabozantinib terminated and its rights to cabozantinib reverted to us, and we received, subject to certain terms and conditions, licenses from Bristol-Myers Squibb to research, develop and commercialize cabozantinib. We have no continuing obligations under these terminated agreements.
	We recognized license and contract revenues of $14.8 million and $28.4 million during the years ended December 31, 2013 and 2012, respectively, under these terminated agreements with Bristol-Myers Squibb. We recognized no such revenue during the year ended December 31, 2014.
	Sanofi
	In May 2009, we entered into a global license agreement with Sanofi for SAR245408 (XL147) and SAR245409 (XL765), leading inhibitors of phosphoinositide-3 kinase (“PI3K”), and a broad collaboration for the discovery of inhibitors of PI3K for the treatment of cancer. The license agreement and collaboration agreement became effective on July 7, 2009. In connection with the effectiveness of the license and collaboration, on July 20, 2009, we received upfront payments of $140.0 million ($120.0 million for the license and $20.0 million for the collaboration), less applicable withholding taxes of $7.0 million, for a net receipt of $133.0 million. We received a refund payment in December 2011 with respect to the withholding taxes previously withheld.
	Under the license agreement, Sanofi received a worldwide exclusive license to SAR245408 (XL147) and SAR245409 (XL765), which are in phase 1, phase 1b/2 and phase 2 clinical trials, and has sole responsibility, including funding, for all subsequent clinical, regulatory, commercial and manufacturing activities. As disclosed on ClinicalTrials.gov, SAR245408 (XL147) is currently being studied in a clinical trial evaluating pharmacokinetics of a tablet formulation in patients with solid tumors or lymphoma (NCT01943838). As disclosed on ClinicalTrials.gov, SAR245409 (XL765) is currently being studied in clinical trials in patients with lymphoma either as a single agent (NCT01403636) or in combination with bendamustine and/or rituximab (NCT01410513). In addition SAR245409 (XL765) is being studied in combination with a MEK inhibitor in patients with locally advanced or metastatic solid tumors (NCT01390818).
	We will be eligible to receive contingent payments associated with development, regulatory and commercial milestones under the license agreement of $745.0 million in the aggregate, as well as royalties on sales of any products commercialized under the license.
	Sanofi may, upon certain prior notice to us, terminate the license as to products containing SAR245408 (XL147) and SAR245409 (XL765). In the event of such termination election, Sanofi’s license relating to such product would terminate and revert to us, and we would receive, subject to certain terms, conditions and potential payment obligations, licenses from Sanofi to research, develop and commercialize such products.
	In December 2011, we entered into an agreement with Sanofi pursuant to which the parties terminated the discovery collaboration agreement and released each other from any potential liabilities arising under the collaboration agreement prior to effectiveness of the termination in December 2011. Each party retains ownership of the intellectual property that it generated under the collaboration agreement, and we granted Sanofi covenants not-to-enforce with respect to certain of our intellectual property rights. The termination agreement also provided that Sanofi would make a payment to us of $15.3 million, which we received in January 2012. If either party or its affiliate or licensee develops and commercializes a therapeutic product containing an isoform-selective PI3K inhibitor that arose from such party’s work (or was derived from such work) under the collaboration agreement, then such party will be obligated to pay royalties to the other party based upon the net sales of such products. The termination agreement provides that Sanofi will make a one-time payment to us upon the first receipt by Sanofi or its affiliate or licensee of marketing approval for the first therapeutic product containing an isoform-selective PI3K inhibitor that arose from Sanofi’s work (or was derived from such work) under the collaboration agreement.
	We did not recognize any revenue under our collaboration agreement with Sanofi during the three years ended December 31, 2014.
	Merck
	In December 2011, we entered into an agreement with Merck pursuant to which we granted Merck an exclusive worldwide license to our PI3K-delta (“PI3K-d”) program, including XL499 and other related compounds. Pursuant to the terms of the agreement, Merck has sole responsibility to research, develop, and commercialize compounds from our PI3K-d program. The agreement became effective in December 2011.
	Merck paid us an upfront cash payment of $12.0 million in January 2012 in connection with the agreement. We will be eligible to receive payments associated with the successful achievement of potential development and regulatory milestones for multiple indications of up to $239.0 million. We will also be eligible to receive payments for combined sales performance milestones of up to $375.0 million and royalties on net-sales of products emerging from the agreement. Contingent payments associated with milestones achieved by Merck and royalties are payable on compounds emerging from our PI3K-d program or from certain compounds that arise from Merck’s internal discovery efforts targeting PI3K-d during a certain period.
	Merck may at any time, upon specified prior notice to us, terminate the license. In addition, either party may terminate the agreement for the other party’s uncured material breach. In the event of termination by Merck at will or by us for Merck’s uncured material breach, the license granted to Merck would terminate. In the event of a termination by us for Merck’s uncured material breach, we would receive a royalty-free license from Merck to develop and commercialize certain joint products. In the event of termination by Merck for our uncured material breach, Merck would retain the licenses from us, and we would receive reduced royalties from Merck on commercial sales of products.
	We recognized license revenues of $10.7 million during the year ended December 31, 2012 under our collaboration agreement with Merck. We did not any recognize any such revenue during the years ended December 31, 2014 and 2013.
	Daiichi Sankyo
	In March 2006, we entered into a collaboration agreement with Daiichi Sankyo for the discovery, development and commercialization of novel therapies targeted against the mineralocorticoid receptor (“MR”), a nuclear hormone receptor implicated in a variety of cardiovascular and metabolic diseases. Under the terms of the agreement, we granted to Daiichi Sankyo an exclusive, worldwide license to certain intellectual property primarily relating to compounds that modulate MR, including CS-3150 (XL550). Daiichi Sankyo is responsible for all further preclinical and clinical development, regulatory, manufacturing and commercialization activities for the compounds and we do not have rights to reacquire such compounds, except as described below.
	Daiichi Sankyo paid us a nonrefundable upfront payment in the amount of $20.0 million and was obligated to provide research and development funding of $3.8 million over a 15-month research term. In June 2007, our collaboration agreement with Daiichi Sankyo was amended to extend the research term by six months over which Daiichi Sankyo was required to provide $1.5 million in research and development funding. In November 2007, the parties decided not to further extend the research term. For each product from the collaboration, we are also entitled to receive payments upon attainment of pre-specified development, regulatory and commercialization milestones. In December 2010, we received a milestone payment of $5.0 million in connection with an IND filing made by Daiichi Sankyo for CS-3150 (XL550) and, in August 2012, we received a milestone payment of $5.5 million in connection with the initiation of a phase 2 clinical trial for CS-3150 (XL550). Daiichi-Sankyo has recently initiated two large phase 2b trials of CS-3150 (XL550) in Japanese patients with hypertension and diabetic nephropathy, respectively. We are eligible to receive additional development, regulatory and commercialization milestone payments of up to $145.0 million. In addition, we are also entitled to receive royalties on any sales of certain products commercialized under the collaboration. Daiichi Sankyo may terminate the agreement upon 90 days’ written notice in which case Daiichi Sankyo’s payment obligations would cease, its license relating to compounds that modulate MR would terminate and revert to us and we would receive, subject to certain terms and conditions, licenses from Daiichi Sankyo to research, develop and commercialize compounds that were discovered under the collaboration.
	We recognized contract revenues of $5.5 million during the year ended December 31, 2012 under our collaboration agreement with Daiichi Sankyo. We did not any recognize any such revenue during the years ended December 31, 2014 and 2013.
	GlaxoSmithKline
	In October 2002, we established a collaboration with GlaxoSmithKline to discover and develop novel therapeutics in the areas of vascular biology, inflammatory disease and oncology. The collaboration involved three agreements: (1) a product development and commercialization agreement, (2) a stock purchase and stock issuance agreement and (3) a loan and security agreement. During the term of the collaboration, we received $65.0 million in upfront and milestone payments, $85.0 million in research and development funding and loans in the principal amount of $85.0 million which have been repaid in full. In connection with the collaboration, GlaxoSmithKline purchased a total of three million shares of our common stock.
	In October 2008, the development term under the collaboration concluded as scheduled. Under the terms of the collaboration, GlaxoSmithKline had the right to select up to two of the compounds in the collaboration for further development and commercialization. GlaxoSmithKline selected foretinib (XL880), an inhibitor of MET and VEGFR2, and had the right to choose one additional compound from a pool of compounds, which consisted of cabozantinib, XL281, XL228, XL820 and XL844 as of the end of the development term.
	In July 2008, we achieved proof-of-concept for cabozantinib and submitted the corresponding data report to GlaxoSmithKline. In October 2008, GlaxoSmithKline notified us in writing that it decided not to select cabozantinib for further development and commercialization and that it waived its right to select XL281, XL228, XL820 and XL844 for further development and commercialization. As a result, we retained the rights to develop, commercialize, and/or license all of the compounds, subject to payment to GlaxoSmithKline of a 3% royalty on net sales of any product incorporating cabozantinib. We have discontinued development of XL820, XL228 and XL844.
	GlaxoSmithKline continues to develop foretinib (XL880), and as disclosed on ClinicalTrials.gov, is currently recruiting patients into phase 1/2 trials studying the activity of foretinib in metastatic breast cancer both as a single agent (NCT01147484) and in combination with lapatinib (NCT01138384), and in non-small cell lung cancer as a single agent and in combination with erlotinib (NCT02034097).
	In connection with the sales of COMETRIQ, during the years ended December 31, 2014 and 2013 we recorded $0.7 million and $0.4 million in royalty expense, respectively, which is included in Cost of Goods Sold on our Consolidated Statements of Operations. We did not recognize any revenue under our agreement with GlaxoSmithKline during the three years ended December 31, 2014.

Disposition_of_Artemis_Pharmac

Disposition of Artemis Pharmaceuticals	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Disposition of Artemis Pharmaceuticals	DISPOSITION OF ARTEMIS PHARMACEUTICALS
	In November 2007, we entered into a share sale and transfer agreement with Taconic Farms, Inc., (“Taconic”), pursuant to which Taconic acquired from us, 80.1% of the outstanding share capital in our wholly-owned subsidiary, Artemis Pharmaceuticals GmbH (“Artemis”). In September 2011, we exercised our right to sell our remaining 19.9% interest in Artemis to Taconic.
	In September 2014, we received a $0.8 million purchase price adjustment resulting from the resolution of contingencies from the September 2011 sale of our remaining interest in Artemis to Taconic. This $0.8 million gain on sale of a business is included in interest income and other, net on our Consolidated Statements of Operations.

Restructurings

Restructurings	12 Months Ended
	Dec. 31, 2014
Restructuring Charges [Abstract]
Restructurings	RESTRUCTURINGS
	The restructuring charges that we expect to incur in connection with our restructurings are subject to a number of assumptions, and actual results may materially differ. We may also incur other material charges not currently contemplated due to events that may occur as a result of, or associated with, the restructurings.
	2014 Restructuring
	On September 2, 2014, as a consequence of the failure of COMET-1, one of our two phase 3 pivotal trials of cabozantinib in metastatic castration-resistant prostate cancer (“mCRPC”), to meet its primary endpoint of demonstrating a statistically significant increase in overall survival for patients treated with cabozantinib as compared to prednisone, we initiated a restructuring plan (the “2014 Restructuring”) to reduce our workforce. Personnel reductions were initiated across our entire organization that when completed will result in a remaining workforce of approximately 80 full-time employees. The principal objective of the 2014 Restructuring was to enable us to focus our financial resources on the phase 3 pivotal trials of cabozantinib in mRCC and advanced HCC.
	We expect to record an aggregate restructuring charge related to one-time termination benefits of approximately $6 million, of which approximately 95% was recorded in 2014 and the remainder is expected to be recorded in 2015. Although we do not yet have contractual commitments in place, we have made progress towards subleasing our facilities and therefore we expect to incur between $2 million and $6 million in facility-related charges as we exit certain facilities. We expect to incur additional charges as a result of the 2014 Restructuring, including property and equipment write-downs and other charges, and expect to record these expenses during fiscal year 2015 as they become determinable and as we exit certain facilities. Except for employee severance and other benefits and certain facility-related charges, we are currently unable to estimate the total amount or range of amounts expected to be incurred in connection with the 2014 Restructuring for each major type of cost or in the aggregate.
	We have recorded a $6.1 million restructuring charge for the 2014 Restructuring during the year ended December 31, 2014. The restructuring charge includes $5.8 million of employee severance and other benefits that were recognized ratably during the period from the implementation date of the 2014 Restructuring through the employees’ termination dates. In addition, we recorded charges of $0.3 million for property and equipment write-downs and other charges, which were partially offset by recoveries recorded in connection with the sale of excess equipment and other assets that were previously fully impaired. The total restructuring liability related to the 2014 Restructuring is included in the current portion of restructuring on the accompanying Consolidated Balance Sheets. The components and changes of these liabilities since initiation of the 2014 Restructuring are summarized in the following table (in thousands):
		Employee Severance and Other Benefits			Asset Impairment and Other			Total
	Restructuring charge	$	5,775		$	312		$	6,087
	Cash payments	(4,507		)	(77		)	(4,584		)
	Adjustments or non-cash credits	22			(288		)	(266		)
	Proceeds from sale of assets	—			100			100
	Restructuring liability for 2014 Restructuring as of December 31, 2014	$	1,290		$	47		$	1,337
	2010 Restructurings
	Between March 2010 and May 2013, we implemented five restructurings (referred to collectively as the “2010 Restructurings”) to manage costs and as a consequence of our decision in 2010 to focus our proprietary resources and development efforts on the development and commercialization of cabozantinib. The aggregate reduction in headcount from the 2010 Restructurings was 429 employees. Charges and credits related to the 2010 Restructurings were recorded in periods other than those in which the 2010 Restructurings were implemented as a result of sublease activities for certain of our buildings in South San Francisco, California, changes in assumptions regarding anticipated sublease activities, the effect of the passage of time on our discounted cash flow computations, previously planned employee terminations, and sales of excess equipment and other assets.
	For the years ended December 31, 2014, 2013 and 2012, we recorded restructuring charges of $1.5 million, $1.2 million and $9.2 million, respectively, for the 2010 Restructurings. The charges for the periods presented were related to the effect of the passage of time on our discounted cash flow computations for the exit, in prior periods, of certain of our South San Francisco buildings and changes in estimates regarding future subleases. During the year ended December 31, 2014, those charges were partially offset by $0.1 million in recoveries recorded in connection with the sale of excess equipment and other assets. The total outstanding restructuring liability related to the 2010 Restructurings is included in the current and long-term portion of restructuring on the accompanying Consolidated Balance Sheets. The components and changes of these liabilities during the year ended December 31, 2014, are summarized in the following table (in thousands):
		Facility			Other			Total
		Charges
	Restructuring liability as of December 31, 2013	$	13,460		$	12		$	13,472
	Restructuring charge (credit)	1,626			(117		)	1,509
	Cash payments	(5,644		)	(8		)	(5,652		)
	Adjustments or non-cash credits	12			(86		)	(74		)
	Proceeds from sale of assets	—			199			199
	Restructuring liability for 2010 Restructurings as of December 31, 2014	$	9,454		$	—		$	9,454
	We expect to pay accrued facility charges of $9.5 million, net of $9.1 million in cash to be received from our subtenants, through the end of our lease terms of the buildings, the last of which ends in 2017. We expect to incur additional restructuring charges of approximately $0.8 million relating to the effect of the passage of time on our discounted cash flow computations used to determine the accrued facilities charges through the end of the building lease terms.

Cash_and_Investments

Cash and Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Cash and Investments	CASH AND INVESTMENTS
	The following table summarizes cash and cash equivalents, investments, and restricted cash and investments by balance sheet line item as of December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents	$	80,395	$	—	$	—		$	80,395
	Short-term investments	63,988		37		(135		)	63,890
	Short-term restricted cash and investments	12,105		107		—			12,212
	Long-term investments	81,600		1		(22		)	81,579
	Long-term restricted cash and investments	4,684		—		—			4,684
	Total cash and investments	$	242,772	$	145	$	(157	)	$	242,760
		December 31, 2013
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents	$	103,978	$	—	$	—		$	103,978
	Short-term investments	138,403		94		(22		)	138,475
	Short-term restricted cash and investments	12,173		40		—			12,213
	Long-term investments	144,226		106		(33		)	144,299
	Long-term restricted cash and investments	16,837		60		—			16,897
	Total cash and investments	$	415,617	$	300	$	(55	)	$	415,862
	Under our loan and security agreement with Silicon Valley Bank, we are required to maintain compensating balances on deposit in one or more investment accounts with Silicon Valley Bank or one of its affiliates. The total collateral balances as of December 31, 2014 and 2013 were $82.0 million and $83.7 million, respectively and are reflected in our Consolidated Balance Sheets in Short- and Long-term investments. See “Note 8 - Debt” for more information regarding the collateral balance requirements under our Silicon Valley Bank loan and security agreement.
	All of our cash equivalents and investments are classified as available-for-sale. The following table summarizes our cash equivalents and investments by security type as of December 31, 2014 and 2013. The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):
		December 31, 2014
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Money market funds	$	23,376	$	—	$	—		$	23,376
	Commercial paper	56,714		—		—			56,714
	Corporate bonds	143,444		35		(157		)	143,322
	U.S. Treasury and government sponsored enterprises	12,105		107		—			12,212
	Municipal bonds	2,659		3		—			2,662
	Total investments	$	238,298	$	145	$	(157	)	$	238,286
		December 31, 2013
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Money market funds	$	24,813	$	—	$	—		$	24,813
	Commercial paper	94,682		—		—			94,682
	Corporate bonds	239,937		190		(55		)	240,072
	U.S. Treasury and government sponsored enterprises	44,284		102		—			44,386
	Municipal bonds	6,005		8					6,013
	Total investments	$	409,721	$	300	$	(55	)	$	409,966
	There were no gains or losses on the sales of investments during the years ended December 31, 2014, 2013 and 2012.
	All of our investments are subject to a quarterly impairment review. During the years ended December 31, 2014 and 2013, we did not record any other-than-temporary impairment charges on our available-for-sale securities. As of December 31, 2014, there were 40 investments in an unrealized loss position with an aggregate fair value $82.8 million. All of our investments in an unrealized loss position are corporate bonds. All investments in an unrealized loss position have been so for less than one year and the unrealized losses were not attributed to credit risk, but rather associated with the changes in interest rates. Based on the scheduled maturities of our investments, we concluded that the unrealized losses in our investment securities are not other-than-temporary, as it is more likely than not that we will hold these investments for a period of time sufficient for a recovery of our cost basis.
	The following summarizes the fair value of securities classified as available-for-sale by contractual maturity as of December 31, 2014 (in thousands):
		Mature within One Year		After One Year through Two Years		Fair Value
	Money market funds	$	23,376	$	—	$	23,376
	Commercial paper	56,714		—		56,714
	Corporate bonds	134,685		8,637		143,322
	U.S. Treasury and government sponsored enterprises	12,212		—		12,212
	Municipal bonds	2,662		—		2,662
	Total	$	229,649	$	8,637	$	238,286
	Cash is excluded from the table above. The classification of certain compensating balances and restricted investments are dependent upon the term of the underlying restriction on the asset and not the maturity date of the investment. Therefore, certain long-term investments and long-term restricted cash and investments have contractual maturities within one year.

Inventory

Inventory	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventory	INVENTORY
	Inventory consists of the following (in thousands):
		December 31,
		2014			2013
	Raw materials	$	1,118		$	529
	Work in process	2,845			2,280
	Finished goods	559			81
	Total	4,522			2,890
	Less: non-current portion included in other assets	(2,141		)	—
	Inventory	$	2,381		$	2,890
	We generally relieve inventory on a first-expiry, first-out basis. Amounts written down related to expiring inventory are charged to cost of sales and totaled $0.2 million and $39 thousand for the years ended December 31, 2014 and 2013, respectively. Inventory recorded as other assets are comprised of raw materials and work in process inventories. There were no other write-downs for obsolete or excess inventory.

Property_And_Equipment

Property And Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property And Equipment	PROPERTY AND EQUIPMENT
	Property and equipment consisted of the following (in thousands):
		December 31,
		2014			2013
	Laboratory equipment	$	13,677		$	15,453
	Computer equipment and software	14,840			14,462
	Furniture and fixtures	3,701			3,691
	Leasehold improvements	16,364			17,031
	Construction-in-progress	120			68
		48,702			50,705
	Less: accumulated depreciation and amortization	(46,270		)	(45,795		)
	Property and equipment, net	$	2,432		$	4,910
	For the years ended December 31, 2014, 2013 and 2012, we recorded depreciation expense of $2.3 million, $3.1 million and $4.8 million, respectively.
	In 2014, 2013 and 2012, we recorded gross asset impairment charges in the amounts of $0.7 million, $0.1 million and $0.3 million, respectively, in connection with the Restructurings. The amount recorded as a restructuring charge for asset impairment, as presented in “Note 4 - Restructurings,” was net of the gain on the sale of such assets. In 2014 and 2012, the gain on the sale of excess equipment was $0.6 million and $0.3 million, respectively. There were no such gains in 2013. Cash proceeds on those sales were $0.4 million, $0.1 million and $0.9 million during 2014, 2013 and 2012, respectively.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	DEBT
	The amortized carrying amount of our debt consists of the following (in thousands):
		December 31,
		2014			2013
	Convertible Senior Subordinated Notes due 2019	$	182,395		$	165,296
	Secured Convertible Notes due 2015	98,880			99,851
	Silicon Valley Bank term loan	80,000			80,000
	Silicon Valley Bank line of credit	381			2,090
	Total debt	361,656			347,237
	Less: current portion	(99,261		)	(11,762		)
	Long-term debt	$	262,395		$	335,475
	Convertible Senior Subordinated Notes due 2019 and Related Concurrent Offering of Our Common Stock
	On August 14, 2012, we issued and sold $287.5 million aggregate principal amount of 4.25% convertible senior subordinated notes due 2019 (the “2019 Notes”). On that date we completed concurrent registered underwritten public offerings in which we sold the 2019 Notes and 34.5 million shares of common stock at a price of $4.25 per share, generating aggregate net proceeds of $416.1 million. The convertible debt offering resulted in net proceeds of $277.7 million after deducting the underwriting discount and offering expenses of $9.3 million and $0.5 million, respectively. The equity offering resulted in net proceeds of $138.4 million after deducting the underwriting discount of $7.7 million and other expenses of $0.5 million.
	The 2019 Notes were issued pursuant to an indenture, as supplemented by a supplemental indenture with Wells Fargo Bank, National Association, as trustee (the “Trustee”), and mature on August 15, 2019, unless earlier converted, redeemed or repurchased. The 2019 Notes bear interest at the rate of 4.25% per annum, payable semi-annually in arrears on February 15 and August 15 of each year, beginning February 15, 2013. Subject to certain terms and conditions, at any time on or after August 15, 2016, we may redeem for cash all or a portion of the 2019 Notes. The redemption price will equal 100% of the principal amount of the 2019 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date.
	Upon the occurrence of certain circumstances, holders may convert their 2019 Notes prior to the close of business on the business day immediately preceding May 15, 2019. On or after May 15, 2019, until the close of business on the second trading day immediately preceding August 15, 2019, holders may surrender their 2019 Notes for conversion at any time. Upon conversion, we will pay or deliver, as the case may be, cash, shares of our common stock or a combination of cash and shares of our common stock, at our election. The initial conversion rate of 188.2353 shares of common stock per $1,000 principal amount of 2019 Notes is equivalent to a conversion price of approximately $5.31 per share of common stock. The conversion rate is subject to adjustment upon the occurrence of certain events.
	If a Fundamental Change, as defined in the indenture governing the 2019 Notes, occurs, holders of the 2019 Notes may require us to purchase for cash all or any portion of their 2019 Notes at a purchase price equal to 100% of the principal amount of the Notes to be purchased plus accrued and unpaid interest, if any, to, but excluding, the Fundamental Change purchase date.
	In connection with the offering of the 2019 Notes, $36.5 million of the proceeds were deposited into an escrow account which contains an amount of permitted securities sufficient to fund, when due, the total aggregate amount of the first six scheduled semi-annual interest payments on the 2019 Notes. As of December 31, 2014, we have used $24.5 million of the amount held in the escrow account to pay the required semi-annual interest payments. The amount held in the escrow account as of December 31, 2014, was $12.2 million and is included in short--term restricted cash and investments. We have pledged our interest in the escrow account to the Trustee as security for our obligations under the 2019 Notes.
	The 2019 Notes are accounted for in accordance with ASC Subtopic 470-20, Debt with Conversion and Other Options. Under ASC Subtopic 470-20, issuers of certain convertible debt instruments that have a net settlement feature and may be settled in cash upon conversion, including partial cash settlement, are required to separately account for the liability (debt) and equity (conversion option) components of the instrument. The carrying amount of the liability component of any outstanding debt instrument is computed by estimating the fair value of a similar liability without the conversion option. The amount of the equity component is then calculated by deducting the fair value of the liability component from the principal amount of the convertible debt instrument. The effective interest rate used in determining the liability component of the 2019 Notes was 10.09%. This resulted in the recognition of $144.3 million as the liability component and the residual $143.2 million as the debt discount with a corresponding increase to paid-in capital, the equity component, for the 2019 Notes. The underwriting discounts of $9.3 million and offering expenses of $0.5 million were allocated between debt issuance costs and equity issuance costs in proportion to the allocation of the proceeds. Debt issuance costs of $4.9 million were included in Other long term assets on our Consolidated Balance Sheets as of the issuance date. Equity issuance costs of $4.9 million related to the convertible debt offering were recorded as an offset to additional paid-in capital.
	The following is a summary of the liability component of the 2019 Notes (in thousands):
		December 31,
		2014			2013
	Net carrying amount of the liability component	$	182,395		$	165,296
	Unamortized discount of the liability component	105,105			122,204
	Principal amount of the 2019 Notes	$	287,500		$	287,500
	The debt discount and debt issuance costs will be amortized as interest expense through August 2019. The following is a summary of interest expense for the 2019 Notes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Stated coupon interest	$	12,253		$	12,219		$	4,582
	Amortization of debt discount and debt issuance costs	17,804			16,201			5,726
	Total interest expense	$	30,057		$	28,420		$	10,308
	The balance of unamortized fees and costs was $3.3 million and $4.0 million as of December 31, 2014 and December 31, 2013, respectively, which is included in Other assets on the accompanying Consolidated Balance Sheets.
	Secured Convertible Notes due June 2015
	In June 2010, we entered into a note purchase agreement with Deerfield Private Design Fund, L.P. and Deerfield Private Design International, L.P., (the “Original Deerfield Purchasers”), pursuant to which, on July 1, 2010, we sold to the Original Deerfield Purchasers an aggregate of $124.0 million initial principal amount of our Secured Convertible Notes due July 1, 2015 (the “Deerfield Notes”) for an aggregate purchase price of $80.0 million, less closing fees and expenses of approximately $2.0 million. As of December 31, 2014 and 2013, the remaining outstanding principal balance on the Deerfield Notes was $104.0 million and $114.0 million, respectively. We refer to the Original Deerfield Purchasers and the New Deerfield Purchasers (identified below) collectively as Deerfield.
	The outstanding principal amount of the Deerfield Notes bears interest in the annual amount of $6.0 million, payable quarterly in arrears. The following is a summary of interest expense for the Deerfield Notes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Stated coupon interest	$	6,000		$	6,000		$	6,000
	Amortization of debt discount and debt issuance costs	11,731			10,089			9,913
	Total interest expense	$	17,731		$	16,089		$	15,913
	The balance of unamortized fees and costs was $1.4 million and $1.4 million as of December 31, 2014 and December 31, 2013, respectively, which is included in Other assets on the accompanying Consolidated Balance Sheets.
	On August 6, 2012, the parties amended the note purchase agreement to permit the issuance of the 2019 Notes and modify certain optional prepayment rights. The amendment became effective upon the issuance of the 2019 Notes and the payment to the Original Deerfield Purchasers of a $1.5 million consent fee. On August 1, 2013, the parties further amended the note purchase agreement to clarify certain of our other rights under the note purchase agreement.
	On January 22, 2014, the note purchase agreement was further amended to provide us with an option to extend the maturity date of our indebtedness under the note purchase agreement to July 1, 2018. Under the terms of the extension option, we have the right to require Deerfield Partners, L.P. and Deerfield International Master Fund, L.P., (the “New Deerfield Purchasers”), to acquire $100.0 million principal amount of the Deerfield Notes and extend the maturity date thereof to July 1, 2018. We are under no obligation to exercise the extension option. To exercise the extension option, we must provide a notice of exercise to Deerfield prior to March 31, 2015. If we exercise the extension option, the Deerfield Notes would mature on July 1, 2018 and bear interest on and after July 2, 2015 at the rate of 7.5% per annum to be paid in cash, quarterly in arrears, and 7.5% per annum to be paid in kind, quarterly in arrears, for a total interest rate of 15% per annum.
	In each of January 2014 and 2013, we made mandatory prepayments of $10.0 million on the Deerfield Notes. We were required to make an additional mandatory prepayment on the Deerfield Notes in January 2015 equal to 15% of certain revenues from collaborative arrangements (“Development/Commercialization Revenue”) received during the prior fiscal year, subject to a maximum prepayment amount of $27.5 million. We have received no such revenue during the year ended December 31, 2014 and therefore there is no minimum prepayment due in 2015. Our obligation to make annual mandatory prepayments equal to 15% of Development/Commercialization Revenue received by us during the prior fiscal year will apply in each of 2016, 2017 and 2018 if we exercise the extension option. However, we will only be obligated to make any such annual mandatory prepayment after exercise of the extension option if the New Deerfield Purchasers provide notice to us of their election to receive the prepayment. Mandatory prepayments relating to Development/Commercialization Revenue will continue to be subject to a maximum annual prepayment amount of $27.5 million. The definition of “Development/Commercialization Revenue” expressly excludes any sale or distribution of drug or pharmaceutical products in the ordinary course of our business, and any proceeds from any Intellectual Property Sales (as further described below).
	As a result of the January 2014 amendment, we are required to notify the applicable Deerfield entities of certain sales, assignments, grants of exclusive licenses or other transfers of our intellectual property pursuant to which we transfer all or substantially all of our legal or economic interests, defined as an Intellectual Property Sale, and the Deerfield entities may elect to require us to prepay the principal amount of the Deerfield Notes in an amount equal to (i) 100% of the cash proceeds of any Intellectual Property Sale relating to cabozantinib and (ii) 50% of the cash proceeds of any other Intellectual Property Sale. Under the note purchase agreement as amended, we may voluntarily prepay the principal amount of the Deerfield Notes as follows (the amount at which we repay in each case below is referred to as the Prepayment Price):
	•	Prior to July 1, 2015: we may prepay all of the principal amount of the Deerfield Notes at any time at a prepayment price equal to the outstanding principal amount, plus accrued and unpaid interest through the date of such prepayment, plus all interest that would have accrued on the principal amount of the Deerfield Notes between the date of such prepayment and the applicable maturity date of the Deerfield Notes if the outstanding principal amount of the Deerfield Notes as of such prepayment date had remained outstanding through the applicable maturity date, plus all other accrued and unpaid obligations; and
	•	If we exercise the extension option: we may at our sole discretion, prepay all of the principal amount of the Deerfield Notes at a prepayment price equal to 105% of the outstanding principal amount of the Deerfield Notes, plus all accrued and unpaid interest through the date of such prepayment, plus, if prior to July 1, 2017, all interest that would have accrued on the principal amount of the Deerfield Notes between the date of such prepayment and July 1, 2017, if the outstanding principal amount of the Deerfield Notes as of such prepayment date had remained outstanding through July 1, 2017, plus all other accrued and unpaid obligations, collectively referred to as the Prepayment Price.
	In lieu of making any portion of the Prepayment Price or mandatory prepayment in cash, subject to certain limitations (including a cap on the number of shares issuable under the note purchase agreement), we have the right to convert all or a portion of the principal amount of the Deerfield Notes into, or satisfy all or any portion of the Prepayment Price amounts or mandatory prepayment amounts with shares of our common stock. Additionally, in lieu of making any payment of accrued and unpaid interest in respect of the Deerfield Notes in cash, subject to certain limitations, we may elect to satisfy any such payment with shares of our common stock. The number of shares of our common stock issuable upon conversion or in settlement of principal and interest obligations will be based upon the discounted trading price of our common stock over a specified trading period. Upon certain changes of control of Exelixis, a sale or transfer of assets in one transaction or a series of related transactions for a purchase price of more than (i) $400 million or (ii) 50% of our market capitalization, Deerfield may require us to prepay the Deerfield Notes at the Prepayment Price. Upon an event of default, as defined in the Deerfield Notes, Deerfield may declare all or a portion of the Prepayment Price to be immediately due and payable.
	In connection with the January 2014 amendment to the note purchase agreement, on January 22, 2014 we issued to the New Deerfield Purchasers two-year warrants (the “2014 Deerfield Warrants”) to purchase an aggregate of 1,000,000 shares of our common stock at an exercise price of $9.70 per share. If we exercise the extension option, the exercise price will be reset to the lower of (x) the existing exercise price and (y) 120% of the volume weighted average price of our common stock for the ten trading days immediately following the date of such extension election. The 2014 Deerfield Warrants are exercisable for a term of two years, subject to a two years extension if we exercise the extension option, and contain certain limitations that prevent the holder of the 2014 Deerfield Warrants from acquiring shares upon exercise of a Warrant that would result in the number of shares beneficially owned by the holder to exceed 9.98% of the total number of shares of our common stock then issued and outstanding. The number of shares for which the 2014 Deerfield Warrants are exercisable and the associated exercise prices are subject to certain adjustments as set forth in the 2014 Deerfield Warrants. In addition, upon certain changes in control of Exelixis, to the extent the 2014 Deerfield Warrants are not assumed by the acquiring entity, or upon certain defaults under the 2014 Deerfield Warrants, the holder has the right to net exercise the 2014 Deerfield Warrants for shares of common stock, or be paid an amount in cash in certain circumstances where the current holders of our common stock would also receive cash, equal to the Black-Scholes Merton value of the 2014 Deerfield Warrants.
	In connection with the issuance of the 2014 Deerfield Warrants, we entered into a registration rights agreement with Deerfield, pursuant to which we agreed to file, no later than February 21, 2014, a registration statement with the Securities and Exchange Commission (“SEC”) covering the resale of the shares of common stock issuable upon exercise of the 2014 Deerfield Warrants.
	In connection with the note purchase agreement, we also entered into a security agreement in favor of Deerfield which provides that our obligations under the Deerfield Notes will be secured by substantially all of our assets except intellectual property. On August 1, 2013, the security agreement was amended to limit the extent to which voting equity interests in any of our foreign subsidiaries shall be secured assets.
	The note purchase agreement as amended and the security agreement include customary representations and warranties and covenants made by us, including restrictions on the incurrence of additional indebtedness.
	Silicon Valley Bank Loan and Security Agreement
	The outstanding principal obligation under the Silicon Valley Bank Loan and Security Agreement, as amended, was $80.4 million and $82.1 million as of December 31, 2014 and 2013, respectively.
	Silicon Valley Bank Line of Credit
	In December 2007, we entered into a loan modification agreement to a loan and security agreement originally entered into in May 2002 with Silicon Valley Bank. The principal amount outstanding under the term loan accrues interest at 0.75% per annum. In accordance with the amended loan terms, the Line of Credit has expired and we have no further draw down obligations under the line of credit. The outstanding principal obligation under the Silicon Valley Bank Line of Credit was $0.4 million and $2.1 million as of December 31, 2014 and 2013, respectively.
	Silicon Valley Bank Term Loan
	In June 2010, we amended our loan and security agreement with Silicon Valley Bank to provide for a new seven-year term loan in the amount of $80.0 million. The principal amount outstanding under the term loan accrues interest at 1.0% per annum, which interest is due and payable monthly. We are required to repay the term loan in one balloon principal payment, representing 100% of the principal balance and accrued and unpaid interest, on May 31, 2017. We have the option to prepay all, but not less than all, of the amounts advanced under the term loan, provided that we pay all unpaid accrued interest thereon that is due through the date of such prepayment and the interest on the entire principal balance of the term loan that would otherwise have been paid after such prepayment date until the maturity date of the term loan. We are required to maintain at all times on deposit in one or more non-interest bearing demand deposit accounts with Silicon Valley Bank or one of its affiliates a compensating balance, constituting support for the obligations under the term loan, with a principal balance in value equal to at least 100% of the outstanding principal balance of the term loan.
	In August 2011, we amended our term loan agreement to allow for the compensating balance to be maintained on deposit in one or more investment accounts with Silicon Valley Bank or one of its affiliates. This compensating balance is to have a value equal to at least 100%, but not to exceed 107%, of the outstanding principal balance of the term loan and all lines of credit associated with Silicon Valley Bank. We are entitled to retain income earned on the amounts maintained in such investment account(s). Any amounts outstanding under the term loan during the continuance of an event of default under the loan and security agreement will, at the election of Silicon Valley Bank, bear interest at a per annum rate equal to 6.0%. If one or more events of default under the loan and security agreement occurs and continues beyond any applicable cure period, Silicon Valley Bank may declare all or part of the obligations under the loan and security agreement to be immediately due and payable and stop advancing money or extending credit to us under the loan and security agreement. The total collateral balance as of December 31, 2014 and 2013 was $82.0 million and $83.7 million, respectively, and is reflected in our Consolidated Balance Sheet in Short- and Long-term Investments as the amounts are not restricted as to withdrawal. However, withdrawal of some or all of this amount such that the collateral balance falls below the required level could result in Silicon Valley Bank declaring the obligation immediately due and payable.
	Future Principal Payments
	Aggregate expected future principal payments of our debt were as follows as of December 31, 2014 (in thousands):
	Year Ending December 31, (1)
	2015	104,381
	2016	—
	2017	80,000
2018	—
2019	287,500
Thereafter	—
____________________
-1	Amounts include principal payments associated with the accretion of discounts and debt issuance costs. For the Deerfield Notes, this table is presented assuming we do not make the election to extend the maturity of those notes and the remaining principal balance will be paid at the current July 2015 maturity date. The actual timing of payments made may differ materially.

Common_Stock_And_Warrants

Common Stock And Warrants	12 Months Ended
	Dec. 31, 2014
Warrants and Rights Note Disclosure [Abstract]
Common Stock And Warrants	COMMON STOCK AND WARRANTS
	Sale of Shares of Common Stock
	In February 2012, we completed a registered public offering of 12.7 million shares of our common stock at a price of $5.17 per share pursuant to a shelf registration statement previously filed with the SEC, which the SEC declared effective on May 8, 2009. We received $65.0 million in net proceeds from the offering after deducting the underwriting discount and related offering expenses.
	In August 2012, we completed a registered underwritten public offering of 34.5 million shares of our common stock at a price of $4.25 per share pursuant to a shelf registration statement previously filed with the SEC, which the SEC declared effective on June 8, 2012. We received $138.4 million in net proceeds after deducting the underwriting discount and related offering expenses. Concurrent with the issuance of the common stock, we sold $287.5 million aggregate principal amount of the Convertible Senior Subordinated Notes due 2019 pursuant to the same registered public offering. See “Note 8 - Debt” for more information regarding the 2019 Notes.
	In January 2014, we completed a registered underwritten public offering of 10.0 million shares of our common stock at a price of $8.00 per share pursuant to a shelf registration statement previously filed with the SEC, which the SEC declared effective on June 8, 2012. We received $75.6 million in net proceeds from the offering after deducting the underwriting discount and related offering expenses.
	Conversion of Debt into Common Stock
	The 2019 Notes and the Deerfield Notes are, under certain circumstances, convertible into shares of our common stock. See “Note 8 - Debt” for more information regarding the conversion features of these instruments.
	Warrants
	On January 22, 2014, in connection with the January 2014 amendment to the note purchase agreement with Deerfield to provide us with the Extension Option, we issued to the New Deerfield Purchasers the 2014 Deerfield Warrants to purchase an aggregate of 1,000,000 shares of our common stock at an exercise price of $9.70 per share in connection with an amendment to the note purchase agreement for the Deerfield Notes. If we exercise the Extension Option, the two year term of the 2014 Deerfield Warrants will be extended by two years and the exercise price will be reset to the lower of (i) the existing exercise price and (ii) 120% of the volume weighted average price of our common stock for the ten trading days immediately following the date of such extension election. Due to the potential increase in term and decrease of the exercise price, the 2014 Deerfield Warrants were recorded as a liability which is included in Other long-term liabilities. The 2014 Deerfield Warrants are recorded at fair value, on a recurring basis, which was $0.9 million and $2.8 million as of December 31, 2014 and January 22, 2014, respectively. We recorded an unrealized gain on the warrants of $1.8 million during the year ended December 31, 2014, which is included in Interest income and other, net. See “Note 10 - Fair Value Measurements” for more information on the valuation of these warrants.
	At December 31, 2014, the following warrants to purchase common stock were outstanding and exercisable:
	Date Issued	Exercise		Expiration Date	Number
		Price per Share			of Shares
	January 22, 2014	$	9.7	January 22, 2016	1,000,000
	The warrants are participating securities. The warrant holders do not have a contractual obligation to share in our losses.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	The following table sets forth the fair value of our financial assets and liabilities that were measured and recorded on a recurring basis as of December 31, 2014 and 2013. We did not have any financial liabilities that were measured and recorded on a recurring basis or Level 3 investments as of December 31, 2013. The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):
		December 31, 2014
		Level 1			Level 2			Level 3		Total
	Financial assets:
	Money market funds	$	23,376		$	—		$	—	$	23,376
	Commercial paper	—			56,714			—		56,714
	Corporate bonds	—			143,322			—		143,322
	U.S. Treasury and government sponsored enterprises	—			12,212			—		12,212
	Municipal bonds	—			2,662			—		2,662
	Total financial assets	$	23,376		$	214,910		$	—	$	238,286
	Financial liabilities:
	Warrants	$	—		$	—		$	921	$	921
	Total financial liabilities	$	—		$	—		$	921	$	921
		December 31, 2013
		Level 1			Level 2			Total
	Money market funds	$	24,813		$	—		$	24,813
	Commercial paper	—			94,682			94,682
	Corporate bonds	—			240,072			240,072
	U.S. Treasury and government sponsored enterprises	—			44,386			44,386
	Municipal bonds	—			6,013			6,013
	Total	$	24,813		$	385,153		$	409,966
	The following is a reconciliation of changes in the net fair value of warrants which are classified as Level 3 in the fair value hierarchy. There were no transfers into or out of Level 3 during the period presented (in thousands):
		Year Ended December 31,
	Balance at beginning of year	$	—
	Issuance of warrants	2,762
	Unrealized gain included in Interest income and other, net	(1,841		)
	Balance at end of year	$	921
	The estimated fair value of our financial instruments that are carried at amortized cost for which it is practicable to determine a fair value was as follows (in thousands):
		December 31, 2014						December 31, 2013
		Carrying			Fair Value			Carrying		Fair Value
		Amount						Amount
	2019 Notes	$	182,395		$	156,889		$	165,296	$	339,883
	Silicon Valley Bank Term Loan	$	80,000		$	79,943		$	80,000	$	79,946
	Silicon Valley Bank Line of Credit	$	381		$	381		$	2,090	$	2,090
	We believe it is not practicable to determine the fair value of the Deerfield Notes due to the unique structure of the instrument that was financed by entities affiliated with Deerfield.
	The carrying amounts of cash, trade and other receivables, accounts payable, accrued clinical trial liabilities, accrued compensation and benefits, and other accrued liabilities approximate their fair values and are excluded from the tables above.
	The following methods and assumptions were used to estimate the fair value of each class of financial instrument for which it is practicable to estimate a value:
	•	When available, we value investments based on quoted prices for those financial instruments, which is a Level 1 input. Our remaining investments are valued using third-party pricing sources, which use observable market prices, interest rates and yield curves observable at commonly quoted intervals of similar assets as observable inputs for pricing, which is a Level 2 input.
	•	The 2019 Notes are valued using a third-party pricing model that is based in part on average trading prices, which is a Level 2 input. The 2019 Notes are not marked-to-market and are shown at their initial fair value less the unamortized discount; the portion of the value allocated to the conversion option is included in Stockholders’ (deficit) equity on the accompanying Consolidated Balance Sheets.
	•	We estimate the fair value of our other debt instruments, where possible, using the net present value of the payments discounted at an interest rate that is consistent with money-market rates that would have been earned on our non-interest-bearing compensating balances, which is a Level 2 input.
	•	The 2014 Deerfield Warrants are valued using a Monte Carlo simulation model. The expected life is based on the contractual terms of the 2014 Deerfield Warrants, and in certain simulations, assumes the two year extension that would result from our exercise of the Extension Option; as of December 31, 2014, we have estimated that it is probable that we will exercise this two-year extension. We consider implied volatility as well as our historical volatility in developing our estimate of expected volatility. The fair value of the 2014 Deerfield Warrants were estimated using the following assumptions, which, except for risk-free interest rate, are Level 3 inputs (dollars in thousands):
		December 31, 2014			22-Jan-14
					(issuance date)
	Fair value of warrants	$	921		$	2,762
	Risk-free interest rate	1.07		%	0.95		%
	Dividend yield	—		%	—		%
	Volatility	96		%	57		%
	Average expected life	3.1 years			3.2 years

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS
	Equity Incentive Plans
	We have several equity incentive plans under which we have granted incentive stock options, non-qualified stock options and RSUs to employees, directors and consultants. The Board of Directors or a designated Committee of the Board is responsible for administration of our employee equity incentive plans and determines the term, exercise price and vesting terms of each option. Prior to May 2011, options issued to our employees had a four-year vesting term, an exercise price equal to the fair market value on the date of grant, and a ten year life from the date of grant (6.2 years for options issued in exchange for options cancelled under our 2009 option exchange program). Stock options issued after May 2011 have a four-year vesting term, an exercise price equal to the fair market value on the date of grant, and a seven year life from the date of grant. RSUs granted to our employees vest over a four year term; RSUs issued after September 29, 2011 vest annually; the remaining unvested portion of RSUs issued prior to September 29, 2011 vest quarterly.
	In December 2005, our Board of Directors adopted a Change in Control and Severance Benefit Plan for executives and certain non-executives. Eligible Change in Control and Severance Benefit Plan participants include our employees with the title of vice president and above. If a participant’s employment is terminated without cause during a period commencing one month before and ending thirteen months following a change in control, as defined in the plan document, then the Change in Control and Severance Benefit Plan participant is entitled to have the vesting of all of such participant’s stock options accelerated with the exercise period being extended to no more than one year.
	Employee Stock Purchase Plan
	In January 2000, we adopted the 2000 Employee Stock Purchase Plan (the “ESPP”). The ESPP allows for qualified employees (as defined in the ESPP) to purchase shares of our common stock at a price equal to the lower of 85% of the closing price at the beginning of the offering period or 85% of the closing price at the end of each six month purchase period. Compensation expense related to our ESPP was $0.8 million, $0.6 million, and $0.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. As of December 31, 2014, we had 1,371,274 shares available for issuance under our ESPP. We issued 669,565 shares, 345,828 shares, and 298,533 shares of common stock during the years ended December 31, 2014, 2013 and 2012, respectively, pursuant to the ESPP at an average price per share of $2.14, $4.13 and $4.08, respectively.
	Stock-Based Compensation
	We recorded and allocated employee stock-based compensation expense for our equity incentive plans and our ESPP as follows (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Research and development expense	$	3,245			$	6,021			$	4,536
	General and administrative expense	6,783				5,948				4,245
	Restructuring-related stock compensation expense (recovery)	(22		)		49				—
	Total employee stock-based compensation expense	$	10,006			$	12,018			$	8,781
	In addition, we recognized stock-based compensation expense of $0.1 million relating to non-employees for the year ended December 31, 2012. Such expense was nominal or zero for the years ended December 31, 2014 and 2013.
	We use the Black-Scholes Merton option pricing model to value our stock options. The expected life computation is based on historical exercise patterns and post-vesting termination behavior. We considered implied volatility as well as our historical volatility in developing our estimate of expected volatility. The fair value of employee stock option awards and ESPP purchases was estimated using the following assumptions and weighted average fair values:
		Stock Options
		2014				2013				2012
	Weighted average grant-date fair value	$	1.46			$	2.97			$	3.24
	Risk-free interest rate	1.8		%		1.51		%		0.81		%
	Dividend yield	—		%		—		%		—		%
	Volatility	85		%		61		%		69		%
	Expected life	5.5 years				5.6 years				5.6 years
		ESPP
		2014				2013				2012
	Weighted average grant-date fair value	$	1.28			$	1.64			$	2.07
	Risk-free interest rate	0.06		%		0.11		%		0.1		%
	Dividend yield	—		%		—		%		—		%
	Volatility	69		%		66		%		68		%
	Expected life	6 months				6 months				6 months
	A summary of all option activity was as follows for the periods presented (dollars in thousands, except per share amounts):
		Shares			Weighted				Weighted		Aggregate
					Average				Average		Intrinsic
					Exercise Price				Remaining		Value
									Contractual
									Term
	Options outstanding at December 31, 2011	17,436,378			$	7.16
	Granted	3,442,696			$	5.45
	Exercised	(181,979	)		$	5.09
	Forfeited	(358,360	)		$	5.88
	Expired	(1,890,185	)		$	7.54
	Options outstanding at December 31, 2012	18,448,550			$	6.85
	Granted	6,694,174			$	5.44
	Exercised	(13,311	)		$	5.06
	Forfeited	(79,942	)		$	5.27
	Expired	(1,066,196	)		$	6.45
	Options outstanding at December 31, 2013	23,983,275			$	6.48
	Granted	10,038,565			$	2.11
	Exercised	(19,090	)		$	6.28
	Forfeited	(4,650,543	)		$	5.34
	Expired	(1,540,215	)		$	8.06
	Options outstanding at December 31, 2014	27,811,992			$	5			4.21 years		$	20
	Exercisable at December 31, 2014	15,403,813			$	6.75			2.57 years		$	—
	At December 31, 2014, a total of 11,470,066 shares were available for grant under our stock option plans.
	The aggregate intrinsic value in the table above represents the total intrinsic value (the difference between our closing stock price on the last trading day of fiscal 2014 and the exercise prices, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on December 31, 2014. The total intrinsic value of options exercised was $27 thousand, $4 thousand, and $0.1 million during 2014, 2013 and 2012, respectively. The total estimated fair value of employee options vested and recorded as expense in 2014, 2013 and 2012 was $8.6 million, $7.4 million and $5.6 million, respectively.
	Of the stock options outstanding as of December 31, 2014, 9,240,165 were granted subject to performance objectives tied to the achievement of clinical goals set by the Compensation Committee of our Board of Directors and will vest in full or part based on achievement of such goals. As of December 31, 2014, we do not consider achievement of those performance objectives to be probable and therefore we have not included any stock-based compensation expense for those stock options. As of December 31, 2014, the grant date fair value of awards outstanding for which we have determined that it is not probable that we will achieve the goals was $12.2 million. As a consequence of the failures of COMET-1 and COMET-2, we determined that achievement of certain performance objectives previously considered to be probable were no longer probable; as a result, during the year ended December 31, 2014, we reversed $1.6 million of previously recorded stock-based compensation expense in connection with such awards and cancelled 2,107,732 stock options with performance objectives which could no longer be achieved.
	The following table summarizes information about stock options outstanding and exercisable at December 31, 2014:
		Options Outstanding									Options Outstanding and
											Exercisable
	Exercise Price Range	Number			Weighted		Weighted				Number of		Weighted
					Average		Average				Exercisable		Average
					Remaining		Exercise						Exercise
					Contractual Life		Price						Price
	$1.46 - $1.70	8,430,075			6.64 years		$	1.7			—
$1.76 - $5.50	4,880,183			3.63 years		$	4.78			3,935,186		$	4.98
$5.51 - $5.60	4,344,546			4.76 years		$	5.52			1,628,954		$	5.53
$5.61 - $5.92	3,397,550			1.99 years		$	5.69			3,335,913		$	5.69
$5.94 - $8.90	4,209,035			2.48 years		$	7.92			3,953,157		$	7.96
$8.99 - $12.10	2,550,603			2.16 years		$	9.73			2,550,603		$	9.73
	27,811,992			4.21 years		$	5			15,403,813		$	6.75
As of December 31, 2014, $19.5 million of total unrecognized compensation expense related to stock options is expected to be recognized over a weighted-average period of 2.73 years.
Cash received from option exercises and purchases under the ESPP in 2014 and 2013 was $1.6 million and $1.5 million, respectively.
A summary of all RSU activity was as follows for all periods presented (dollars in thousands, except per share amounts):
	Shares			Weighted				Weighted		Aggregate
				Average				Average		Intrinsic
				Grant Date				Remaining		Value
				Fair Value				Contractual
								Term
Awards outstanding at December 31, 2011	1,391,691			$	6.92
Awarded	733,958			$	5.5
Released	(596,397	)		$	7.15
Forfeited	(234,631	)		$	6.62
Awards outstanding at December 31, 2012	1,294,621			$	6.07
Awarded	1,119,733			$	5.45
Released	(517,874	)		$	6.6
Forfeited	(85,959	)		$	5.49
Awards outstanding at December 31, 2013	1,810,521			$	5.56
Awarded	559,659			$	1.94
Released	(459,939	)		$	4.96
Forfeited	(948,772	)		$	5.48
Awards outstanding at December 31, 2014	961,469			$	3.82			1.88 years		$	1,586
As of December 31, 2014, $2.6 million of total unrecognized compensation expense related to employee RSUs was expected to be recognized over a weighted-average period of 1.88 years.
401(k) Retirement Plan
We sponsor a 401(k) Retirement Plan (the “401(k) Plan”) whereby eligible employees may elect to contribute up to the lesser of 50% of their annual compensation or the statutorily prescribed annual limit allowable under Internal Revenue Service regulations. The 401(k) Plan permits us to make matching contributions on behalf of all participants. Beginning in 2002 through 2010, we matched 50% of the first 4% of participant contributions into the 401(k) Plan in the form of our common stock. Beginning in January 2011, we matched 100% of the first 3% of participant contributions into the 401(k) Plan in the form of our common stock. We recorded expense of $1.1 million, $0.8 million, and $0.6 million related to the stock match for the years ended December 31, 2014, 2013 and 2012, respectively.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	The income tax (benefit) provision is based on the following loss before income taxes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Domestic	$	(237,780	)	$	(236,076	)	$	(147,538	)
	Foreign	(30,944		)	(8,780		)	—
	Total	$	(268,724	)	$	(244,856	)	$	(147,538	)
	Income tax expense (benefit) consists of the following for the periods shown below (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Current:
	Federal	$	—		$	—		$	32
	State	(182		)	12			75
	Total current tax expense	(182		)	12			107
	Deferred:
	Federal	—			(106		)	—
	State	—			(2		)	—
	Total deferred tax expense	—			(108		)	—
	Income tax (benefit) provision	$	(182	)	$	(96	)	$	107
	The 2014 income tax benefit of $0.2 million resulted from a state tax benefit related to the lapse of the applicable statute of limitations in California for the 2009 tax year, offset by current year state income tax expense. The 2013 income tax benefit of $0.1 million resulted from the exception to the general intra-period allocation rules required by ASC 740-20-45-7, and is related to the income tax effect of unrealized gains on available-for-sale investments included in other comprehensive loss. The $0.1 million income tax provision in 2012 related to an adjustment resulting from a further evaluation of qualified expenses for refunds received in 2009 and 2010 as a result of the enactment of the Housing and Economy Recovery Act of 2008 and the American Recovery and Reinvestment Tax Act of 2009.
	During 2013, Exelixis Bermuda acquired the existing and future intellectual property rights to exploit cabozantinib in jurisdictions outside of the United States. The transfer of the existing rights created a taxable gain in the U.S. and state jurisdictions. For tax purposes, that gain is primarily offset by current fiscal year losses and the remainder through the utilization of an insignificant amount of net operating loss carry-forwards for which there is a corresponding reduction to our valuation allowance. Because this was an intercompany transaction, ASC 740-10-25-3(e) applies, however, there was no impact to tax expense due to the full valuation allowance and therefore no deferred prepaid charge was recorded to the balance sheet.
	A reconciliation of income taxes at the statutory federal income tax rate to our income tax (benefit) provision included in the Consolidated Statements of Operations is as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	U.S. federal income tax (benefit) provision at statutory rate	$	(91,366	)	$	(83,251	)	$	(50,163	)
	Unutilized net operating losses	87,448			(3,438		)	46,324
	Non-deductible interest	3,598			3,380			3,297
	Stock-based compensation	255			393			504
	State tax expense	(182		)	10			74
	Refundable tax credit	—			—			32
	Available-for-sale investments	—			(106		)	—
	Impact of intellectual property rights transfer	—			82,858			—
	Other	65			58			39
	Income tax (benefit) provision	$	(182	)	$	(96	)	$	107
	Deferred tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carry-forwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting and the amounts used for income tax purposes.
	Our deferred tax assets and liabilities consist of the following (in thousands):
		December 31,
		2014			2013
	Deferred tax assets:
	Net operating loss carry-forwards	$	446,343		$	358,372
	Tax credit and charitable contribution carry-forwards	64,368			64,635
	Amortization of deferred stock compensation – non-qualified	27,500			24,279
	Accruals and reserves not currently deductible	6,521			10,107
	Deferred revenue	988			502
	Book over tax depreciation and amortization	5,118			4,499
	Total deferred tax assets	550,838			462,394
	Valuation allowance	(511,171		)	(421,426		)
	Net deferred tax assets	39,667			40,968
	Deferred tax liabilities:
	Unrealized gain on derivatives	(704		)	—
	Convertible debt	(38,963		)	(40,968		)
	Total deferred tax liabilities	(39,667		)	(40,968		)
	Net deferred taxes	$	—		$	—
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $89.7 million, decreased by $16.8 million, and increased by $6.8 million during 2014, 2013 and 2012, respectively.
	At December 31, 2014, we had federal net operating loss carry-forwards of approximately $1,213 million which expire in the years 2020 through 2034, and federal business tax credits of approximately $75 million which expire in the years 2020 through 2029. We also had state net operating loss carry-forwards of approximately $1,052 million, which expire in the years 2015 through 2034, California research and development tax credits of approximately $25 million which have no expiration. Included in the federal and state carry-forwards is $16 million related to deductions from the exercise of stock options and the related tax benefit that will result in an increase in additional paid-in capital if and when realized through a reduction of taxes paid in cash.
	Under the Internal Revenue Code and similar state provisions, certain substantial changes in our ownership could result in an annual limitation on the amount of net operating loss and credit carry-forwards that can be utilized in future years to offset future taxable income. The annual limitation may result in the expiration of net operating losses and credit carry-forwards before utilization. We completed a Section 382 study through December 31, 2014, and concluded that an ownership change, as defined under Section 382, had not occurred.
	ASC Topic 740-10 clarifies the accounting for uncertainty in income taxes by prescribing the recognition threshold a tax position is required to meet before being recognized in the financial statements. It also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The following table summarizes the activity related to our unrecognized tax benefits for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Beginning balance	$	55,077		$	47,298		$	39,310
	Increase (decrease) relating to prior year provision	719			(112		)	5,894
	Increase relating to current year provision	2,706			7,891			2,094
	Reductions based on the lapse of the applicable statutes of limitations	(287		)	—			—
	Ending balance	$	58,215		$	55,077		$	47,298
Included in the balance of unrecognized tax benefits as of December 31, 2013 and 2012 $0.1 million, and $0.1 million, respectively, of tax benefits that if recognized would affect the effective tax rate. There were no such unrecognized benefits as of December 31, 2014. All of our deferred tax assets are subject to a valuation allowance. As of December 31, 2013 and 2012, we had an accrued interest balance of $20 thousand and $15 thousand, respectively, related to tax contingencies. Interest expense related to those tax contingencies was $4 thousand and $6 thousand during the years ended December 31, 2013 and 2012, respectively. There were no such interest accruals or expenses during the year ended December 31, 2014. There were no penalties recognized or accrued during any of the periods presented. Any tax-related interest and penalties are included in income tax (benefit) provision in the Consolidated Statements of Operations. We do not anticipate that the amount of unrecognized tax benefits existing as of December 31, 2014, will significantly decrease over the next 12 months.
We file U.S. and state income tax returns in jurisdictions with varying statues of limitations during which such tax returns may be audited and adjusted by the relevant tax authorities. The 1998 through 2013 years generally remain subject to examination by federal and most state tax authorities to the extent of net operating losses and credits generated during these periods and are being utilized in the open tax periods.
It is our intention to reinvest the earnings of our non-U.S. subsidiaries in those operations. As of December 31, 2014, there were no undistributed foreign earnings of our only non-U.S. subsidiary, Exelixis Bermuda.

Net_Loss_Per_Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Loss Per Share	NET LOSS PER SHARE
	The following table sets forth a reconciliation of basic and diluted net loss per share (in thousands, except per share amounts):
		Year Ended December 31,
		2014				2013			2012
	Numerator:
	Net loss	$	(268,542	)		$	(244,760	)	$	(147,645	)
	Denominator:
	Shares used in computing basic and diluted net loss per share	194,299				184,062			160,138
	Net loss per share, basic and diluted	$	(1.38	)		$	(1.33	)	$	(0.92	)
	The following table sets forth outstanding potential shares of common stock outstanding as of dates presented that are not included in the computation of diluted net loss per share because to do so would be anti-dilutive (in thousands):
		December 31,
		2014			2013			2012
	Convertible debt	75,734			54,123			54,123
	Outstanding stock options, unvested RSUs and ESPP contributions	28,930			21,401			16,568
	Warrants	1,000			1,441			1,441
	Total potentially dilutive shares	105,664			76,965			72,132

Commitments

Commitments	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments	COMMITMENTS
	Leases
	We lease office and research space and certain equipment under operating leases that expire at various dates through the year 2018. Certain operating leases contain renewal provisions and require us to pay other expenses. As a result of the Restructurings, we exited certain facilities in South San Francisco. Aggregate future minimum lease payments under our operating leases are as follows (in thousands):
	Year Ending December 31,	Operating
		Leases (1)
	2015	$	20,152
	2016	16,431
	2017	9,104
	2018	2,806
	Thereafter	—
		$	48,493
	____________________
	-1	Minimum payments have not been reduced by minimum sublease rentals of $9.2 million due in the future under noncancelable subleases.
	The following is a summary of aggregate future minimum lease payments under operating leases at December 31, 2014, by operating lease agreements (in thousands):
		Original	Renewal Options	Future
		Term		Minimum
		(Expiration)		Lease
				Payments
	Building Lease #1 and 2	May-17	2 additional periods of 5 years	$	27,556
	Building Lease #3	Jul-18	1 additional period of 5 years	16,660
	Building Lease #4	Dec-15	1 additional period of 3 years	4,211
	Other			66
	Total			$	48,493
	Rent expense under operating leases was $10.3 million, $9.1 million, and $17.8 million for the years ended December 31, 2014, 2013 and 2012, respectively. Rent expense was recorded net of sublease rental incomes of $4.9 million, $4.1 million and $3.8 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Letters of Credit and Restricted Cash
	We entered into a standby letter of credit with a bank in July 2004, which is related to a building lease, with a credit limit of $0.5 million at both December 31, 2014 and 2013. We entered into two standby letters of credit with a bank in May 2007, which is related to our workers compensation insurance policy, for a combined credit limit of $0.7 million at both December 31, 2014 and 2013, respectively. All three letters of credit are fully collateralized by long-term restricted cash and investments. As of December 31, 2014, the full amount of our three letters of credit was still available.
	As part of a purchasing card program with a bank we initiated during 2007, we were required to provide collateral in the form of a non-interest bearing certificate of deposit. The collateral at both December 31, 2014 and 2013 was $3.5 million. We recorded these amounts in the Consolidated Balance Sheet as Long-term restricted cash and investments as the certificates of deposit were restricted as to withdrawal.
	Indemnification Agreements
	In connection with the sale of our plant trait business, we agreed to indemnify the purchaser and its affiliates up to a specified amount if they incur damages due to any infringement or alleged infringement of certain patents. We have certain collaboration licensing agreements that contain standard indemnification clauses. Such clauses typically indemnify the customer or vendor for an adverse judgment in a lawsuit in the event of our misuse or negligence. We consider the likelihood of an adverse judgment related to any of our indemnification agreements to be remote. Furthermore, in the event of an adverse judgment, any losses under such an adverse judgment may be substantially offset by corporate insurance.

Concentrations_of_Credit_Risk

Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2014
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	CONCENTRATIONS OF CREDIT RISK
	Financial instruments that potentially subject us to concentrations of credit risk are primarily trade and other receivables and investments. Investments consist of money market funds, taxable commercial paper, corporate bonds with high credit quality, U.S. Treasury and government sponsored enterprises, and municipal bonds. All investments are maintained with financial institutions that management believes are creditworthy.
	Trade and other receivables are unsecured and are concentrated in the pharmaceutical and biotechnology industries. Accordingly, we may be exposed to credit risk generally associated with pharmaceutical and biotechnology companies. We have incurred no bad debt expense since inception. As of December 31, 2014, 92% of our trade and other receivables are with the specialty pharmacy that sells COMETRIQ in the United States. This customer has historically paid promptly and within its payment terms. All of our long-lived assets are located in the United States.
	We have operations primarily in the United States, while some of our collaboration partners have headquarters outside of the United States and some of our clinical trials for cabozantinib are conducted outside of the United States. During the second quarter of 2013, we initiated a Named Patient Use (“NPU”) program through our distribution partner, Swedish Orphan Biovitrum (“Sobi”), to support the distribution and commercialization of COMETRIQ for metastatic MTC primarily in the European Union and potentially other countries. In March 2014, the European Commission approved cabozantinib for the treatment of adult patients with progressive, unresectable locally advanced or metastatic MTC, also under the brand name COMETRIQ. In June 2014, we began selling COMETRIQ to Sobi in preparation for commercial sales in certain countries in the European Union. The following table shows the percentage of revenues earned in the United States and the European Union.
		Year Ended December 31,
		2014		2013		2012
	Percentage of revenues earned in the United States	99	%	97	%	100	%
	Percentage of revenues earned in the European Union	1	%	3	%	—	%
	We recorded a $0.5 million gain relating to foreign exchange fluctuations for the fiscal year ended December 31, 2014. Such gains and losses were nominal in 2013 and 2012.
	Net product revenues in the European Union for the year ended December 31, 2014 included a $2.3 million reduction to revenue for a project management fee payable to our European distributor upon their achievement of a cumulative revenue goal.
	The following table sets forth the percentage of revenues recognized under our collaboration agreements and product sales to the specialty pharmacy that represent 10% or more of total revenues:
		Year Ended December 31,
		2014		2013		2012
	Product sales:
	Diplomat Specialty Pharmacy	99	%	45	%	—	%
	Collaboration agreement:
	Bristol-Myers Squibb	—	%	52	%	66	%
	Merck	—	%	—	%	22	%
	Daiichi Sankyo	—	%	—	%	12	%

Quarterly_Financial_Data_Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	QUARTERLY FINANCIAL DATA (UNAUDITED)
	The following tables summarize the unaudited quarterly financial data for the last two fiscal years (in thousands, except per share data):
		Quarter Ended
		December 31,			September 30,			June 30,			March 31,
	2014:00:00
	Revenues	$	7,353		$	6,291		$	6,562		$	4,905
	Gross profit	$	6,669		$	5,718		$	6,085		$	4,596
	Loss from operations	$	(46,208	)	$	(51,574	)	$	(61,688	)	$	(64,988	)
	Net loss	$	(57,953	)	$	(62,560	)	$	(73,410	)	$	(74,619	)
	Net loss per share, basic and diluted	$	(0.30	)	$	(0.32	)	$	(0.38	)	$	(0.39	)
	2013:00:00
	Revenues	$	4,347		$	5,466		$	11,856		$	9,669
	Gross profit	$	4,084		$	5,176		$	11,571		$	9,389
	Loss from operations	$	(59,514	)	$	(55,913	)	$	(51,295	)	$	(34,010	)
	Net loss	$	(70,746	)	$	(67,124	)	$	(62,161	)	$	(44,729	)
	Net loss per share, basic and diluted	$	(0.38	)	$	(0.36	)	$	(0.34	)	$	(0.24	)

Organization_And_Summary_Of_Si1

Organization And Summary Of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization
	Exelixis, Inc. (“Exelixis,” “we,” “our” or “us”) is a biopharmaceutical company committed to developing small molecule therapies for the treatment of cancer. We were incorporated in Delaware in November 1994 as Exelixis Pharmaceuticals, Inc. and we changed our name to Exelixis, Inc. in February 2000. Our two most advanced assets are cabozantinib, our wholly-owned inhibitor of multiple receptor tyrosine kinases, and cobimetinib, a potent, highly selective inhibitor of MEK, a serine/threonine kinase, which we out-licensed to Genentech (a member of the Roche Group) (“Genentech”).
	Our development and commercialization efforts are focused primarily on cabozantinib. We are evaluating cabozantinib in a broad development program comprising over forty-five clinical trials, across multiple indications, including two ongoing phase 3 pivotal trials focusing on metastatic renal cell carcinoma (“mRCC”), and advanced hepatocellular carcinoma (“HCC”).
	Cabozantinib was approved by the United States Food and Drug Administration, (“FDA”), on November 29, 2012, for the treatment of progressive, metastatic medullary thyroid cancer (“MTC”) in the United States under the brand name COMETRIQ(R). COMETRIQ became commercially available in the United States in January 2013. In March 2014, the European Commission granted cabozantinib conditional marketing authorization for the treatment of adult patients with progressive, unresectable locally advanced or metastatic MTC, also under the brand name COMETRIQ.
	Our second most advanced oncology asset, cobimetinib, is being evaluated by Genentech in a broad development program, including coBRIM, a phase 3 pivotal trial evaluating cobimetinib in combination with vemurafenib in previously untreated patients with unresectable locally advanced or metastatic melanoma harboring a BRAF V600 mutation. Roche has completed the Marketing Authorization Application (“MAA”), for cobimetinib in combination with vemurafenib in the European Union. In the United States, Genentech filed its New Drug Application (“NDA”) in December 2014.
Basis of Consolidation	Basis of Consolidation
	The consolidated financial statements include the accounts of Exelixis and those of our wholly-owned subsidiaries, including Exelixis International (Bermuda) Ltd. (“Exelixis Bermuda”). Effective July 2013, Exelixis engaged in intercompany transactions whereby Exelixis Bermuda acquired the existing and future intellectual property rights to exploit cabozantinib in jurisdictions outside of the United States. Exelixis Bermuda’s functional currency is the U.S. Dollar. All intercompany balances and transactions have been eliminated.
Basis of Presentation	Basis of Presentation
	Exelixis has adopted a 52- or 53-week fiscal year that generally ends on the Friday closest to December 31st. Fiscal year 2012, a 52-week year, ended on December 28, 2012, fiscal year 2013, a 52-week year, ended on December 27, 2013, fiscal year 2014, a 53-week year, ended on January 2, 2015 and fiscal year 2015, a 52-week year, will end on January 1, 2016. For convenience, references in this report as of and for the fiscal years ended December 28, 2012, December 27, 2013 and January 2, 2015, are indicated on a calendar year basis, ended December 31, 2012, 2013 and 2014, respectively. The quarter ended January 2, 2015 is a 14-week fiscal quarter; all other interim periods presented are 13-week fiscal quarters.
Segment Information	Segment Information
	We operate as a single reportable segment.
Use Of Estimates	Use of Estimates
	The preparation of our consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make judgments. The preparation of our consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, including for deductions from revenues (such as rebates, chargebacks, sales returns and sales allowances), recoverability of inventory, certain accrued liabilities including clinical trial accruals and restructuring liabilities, the valuation of the debt and equity components of our convertible debt at issuance, valuation of warrants, and share-based compensation. We base our estimates on historical experience and on various other market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ materially from those estimates.
Cash	Cash and Investments
	We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cash equivalents include investments in high-grade, short-term money market funds, commercial paper and municipal securities, which are subject to minimal credit and market risk.
Investments	We have designated all investments as available-for-sale and therefore, such investments are reported at fair value, with unrealized gains and losses recorded in accumulated other comprehensive (loss) income. For securities sold prior to maturity, the cost of securities sold is based on the specific identification method. Realized gains and losses on the sale of investments are recorded in interest and other income, net.
	We classify those investments we do not require for use in current operations that mature in more than 12 months as Long-term investments on our Consolidated Balance Sheets. Additionally, those investments that collateralize loan balances with terms that extend 12 months or longer were classified as long-term investments even if the investment’s remaining term to maturity was one year or less; they are not restricted to withdrawal.
	All of our investments are subject to a quarterly impairment review. We recognize an impairment charge when a decline in the fair value of its investments below the cost basis is judged to be other-than-temporary. Factors considered in determining whether a loss is temporary included the length of time and extent to which the investments fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, extent of the loss related to credit of the issuer, the expected cash flows from the security, our intent to sell the security and whether or not we will be required to sell the security before the recovery of its amortized cost. During the years ended December 31, 2014, 2013, and 2012, we did not record any significant other-than-temporary impairment charges on our available-for-sale securities.
Fair Value Measurements	Fair Value Measurements
	Fair value reflects the amounts that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We disclose the fair value of financial instruments for assets and liabilities for which the value is practicable to estimate. For those financial instruments measured and recorded at fair value on a recurring basis, we also provide fair value hierarchy information in these Notes to Consolidated Financial Statements. The fair value hierarchy has the following three levels:
	Level 1 – quoted prices (unadjusted) in active markets for identical assets and liabilities that the reporting entity can access at the measurement date.
	Level 2 – observable inputs, other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly. These inputs include using prices from independent pricing services based on quoted prices in active markets for similar instruments or on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets.
	Level 3—unobservable inputs.
	A review of the fair value hierarchy classification is conducted on a quarterly basis. Changes in the observability of valuation inputs may result in a reclassification of levels for certain investments within the fair value hierarchy.
Inventory	Inventory
	Inventory is valued at the lower of cost or net realizable value. We determine the cost of inventory using the standard-cost method, which approximates actual cost based on a first-in, first-out method. We analyze our inventory levels quarterly and write down inventory subject to expiry in excess of expected requirements, or has a cost basis in excess of its expected net realizable value. The related costs are recognized as cost of goods sold in the Consolidated Statements of Operations.
	We analyze our estimated production levels for the following twelve month period quarterly and reclassify inventory we do not expect to use within the next twelve months in Other assets in the Consolidated Balance Sheets.
	We consider regulatory approval of product candidates to be uncertain and product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained. As such, the manufacturing costs for product candidates incurred prior to regulatory approval were not capitalized as inventory but were expensed as research and development costs. When regulatory approval is obtained, we begin capitalization of inventory related costs.
Property And Equipment	Property and Equipment
	Property and equipment are recorded at cost and depreciated using the straight-line method over the following estimated useful lives:
	Equipment and furniture	5 years
	Computer equipment and software	3 years
	Leasehold improvements	Shorter of lease life or 7 years
	Capitalized software includes certain internal use computer software costs.
	Repairs and maintenance costs are charged to expense as incurred.
Goodwill	Goodwill
	Goodwill amounts have been recorded as the excess purchase price over tangible assets, liabilities and intangible assets acquired based on their estimated fair value, by applying the purchase method. Goodwill is not subject to amortization. We evaluate goodwill for impairment on an annual basis and on an interim basis if events or changes in circumstances between annual impairment tests indicate that the asset might be impaired. When evaluating goodwill for impairment we must determine the reporting units that exist within Exelixis. We have determined that we have one reporting unit as of December 31, 2014 and 2013.
Long-Lived Assets	Long-Lived Assets
	Long-lived assets include property and equipment. The carrying value of our long-lived assets is reviewed for impairment whenever events or changes in circumstances indicate that the asset may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of the asset and its eventual disposition is less than its carrying amount.
Revenue Recognition	Revenue Recognition
	We recognize revenue from the sale of COMETRIQ and from license fees, milestones and contingent payments earned on research and collaboration arrangements.
	License and Contract Revenues
	License, research commitment and other non-refundable payments received in connection with research collaboration agreements are deferred and recognized on a straight-line basis over the period of continuing involvement, generally the research term specified in the agreement. Contract research revenues are recognized as services are performed pursuant to the terms of the agreements. Any amounts received in advance of performance are recorded as deferred revenue. Payments are not refundable if research is not successful. License fees are classified as license revenues in our Consolidated Statements of Operations.
	We enter into corporate collaborations under which we may obtain upfront license fees, research funding, contingent, milestone and royalty payments. Our deliverables under these arrangements typically consist of intellectual property rights and research and development services. We evaluate whether the delivered elements under these arrangements have value to our collaboration partner on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered item exists. If we determine that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. A delivered item or items that do not qualify as a separate unit of accounting within the arrangement shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. A delivered item or items that do not have stand-alone value to our collaboration partner shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. For a combined unit of accounting, non-refundable upfront fees and milestones are recognized in a manner consistent with the final deliverable, which has generally been ratably over the period of the research and development obligation.
	Contingency payments (received upon the achievement of certain events by our collaborators) and milestone payments (received upon the achievement of certain events by us) are non-refundable and recognized as revenues over the period of the research arrangement. This typically results in a portion of the payments being recognized at the date the contingency or milestone is achieved, which portion is equal to the applicable percentage of the research term that has elapsed at the date of achievement, and the balance being recognized over the remaining research term of the agreement. In certain situations, we may receive contingent payments after the end of our period of continued involvement. In such circumstances, we would recognize 100% of the contingent revenues when the contingency is achieved. Contingency and milestones payments, when recognized as revenue, are classified as contract revenues in our Consolidated Statements of Operations.
	Revenues and expenses from collaborations that are not co-development agreements are recorded as contract revenues or research and development expenses in the period incurred.
	Net Product Revenues
	We recognize revenue when it is both realized or realizable and earned, meaning persuasive evidence of an arrangement exists, delivery has occurred, title has transferred, the price is fixed or determinable, there are no remaining customer acceptance requirements, and collectability of the resulting receivable is reasonably assured. For product sales in the United States, this generally occurs upon shipment of the product to the patient by our distributor. For product sales in Europe, this occurs when our European distribution partner has accepted the product.
	We sell our product, COMETRIQ, in the United States to a specialty pharmacy that benefits from customer incentives and has a right of return. We have a limited sales history and cannot reliably estimate expected returns of the product nor the discounts and rebates due to payers at the time of shipment to the specialty pharmacy. Accordingly, upon shipment to the specialty pharmacy, we record deferred revenue on our Consolidated Balance Sheets. We recognize revenue when the specialty pharmacy provides the product to a patient based on the fulfillment of a prescription. We record revenue using an analysis of prescription data from our specialty pharmacy to ascertain the date of shipment and the payer mix. This approach is frequently referred to as the “sell-through” revenue recognition model. Once the prescription has been provided to the patient, it is not subject to return unless the product is damaged.
	Product sales to our European distribution partner are not subject to rights of return or discounts and allowances. We record revenue at the time our European distribution partner has accepted the product, a method also known as the “sell-in” revenue recognition model.
	Product Sales Discounts and Allowances
	We calculate gross product revenues based on the price that we charge our United States specialty pharmacy and our European distribution partner. We estimate our domestic net product revenues by deducting from our gross product revenues (a) trade allowances, such as discounts for prompt payment, (b) estimated government rebates and chargebacks, and (c) estimated costs of patient assistance programs. We initially record estimates for these deductions at the time we recognize the gross revenue. We update our estimates on a recurring basis as new information becomes available.
	Customer Credits: The United States specialty pharmacy receives a discount of 2% for prompt payment. We expect this specialty pharmacy will earn 100% of its prompt payment discounts and, therefore, we deduct the full amount of these discounts from total product sales when revenues are recognized.
	Mandated Rebates: Allowances for rebates include mandated discounts under the Medicaid Drug Rebate Program and other government programs. Rebate amounts owed after the final dispensing of the product to a benefit plan participant are based upon contractual agreements or legal requirements with public sector benefit providers, such as Medicaid. The allowance for rebates is based on statutory discount rates and expected utilization. Our estimates for the expected utilization of rebates are based on customer and payer data received from the United States specialty pharmacy. Rebates are generally invoiced by the payer and paid in arrears, such that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s shipments to patients, plus an accrual balance for known prior quarter’s unpaid rebates. If actual future rebates vary from estimates, we may need to adjust our accruals, which would affect net revenue in the period of adjustment.
	Chargebacks: Chargebacks are discounts that occur when contracted customers purchase directly from a specialty pharmacy. Contracted customers, which currently consist primarily of Public Health Service institutions, non-profit clinics, and Federal government entities purchasing via the Federal Supply Schedule, generally purchase the product at a discounted price. The United States specialty pharmacy, in turn, charges back to us the difference between the price initially paid by the specialty pharmacy and the discounted price paid to the specialty pharmacy by the customer. The allowance for chargebacks is based on sales to contracted customers.
	Medicare Part D Coverage Gap: In the United States, the Medicare Part D prescription drug benefit mandates manufacturers to fund 50% of the Medicare Part D insurance coverage gap for prescription drugs sold to eligible patients. Our estimates for expected Medicare Part D coverage gap are based in part on third party market research data and on customer and payer data received from the United States specialty pharmacy. Funding of the coverage gap is invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter's shipments to patients, plus an accrual balance for prior sales. If actual future funding varies from estimates, we may need to adjust our accruals, which would affect net revenue in the period of adjustment.
	Co-payment Assistance: Patients who have commercial insurance and meet certain eligibility requirements may receive co-payment assistance. We accrue a liability for co-payment assistance based on actual program participation and estimates of program redemption using customer data provided by our United States specialty pharmacy.
	Our European distribution partner is entitled to receive a project management fee based upon the achievement of a pre-specified revenue goal which, when deemed probable, is ratably accrued as a reduction to gross revenue.
	Patient Assistance Program
	We provide COMETRIQ at no cost to eligible patients who have no insurance and meet certain financial and clinical criteria through our Patient Assistance Program (“PAP”). We record the cost of the product as a selling, general and administrative expense at the time the product is designated as PAP inventory.
Cost of Goods Sold	Cost of Goods Sold
	Cost of goods sold is related to our product revenues and consists primarily of a 3% royalty and indirect labor costs, and to a lesser extent, the cost of manufacturing and other third party logistics costs of our product. A significant portion of the manufacturing costs for product sales were incurred prior to regulatory approval of COMETRIQ for the treatment of progressive, metastatic MTC and, therefore, were expensed as research and development costs when those costs were incurred, rather than capitalized as inventory.
	In accordance with our product development and commercialization agreement with GlaxoSmithKline, we are required to pay GlaxoSmithKline a 3% royalty on the Net Sales of any product incorporating cabozantinib, including COMETRIQ. Net Sales is defined in the product development and commercialization agreement generally as the gross invoiced sales price less customer credits, rebates, chargebacks, shipping costs, customs duties, and sales tax and other similar tax payments we are required to make.
Research And Development Expenses	Research and Development Expenses
	Research and development costs are expensed as incurred and include costs associated with research performed pursuant to collaborative agreements. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research activities on our behalf.
	Substantial portions of our preclinical studies and all of our clinical trials have been executed with support from third-party contract research organizations (“CROs”) and other vendors. We accrue expenses for preclinical studies performed by our vendors based on certain estimates over the term of the service period and adjust our estimates as required. We accrue expenses for clinical trial activities performed by CROs based upon the estimated amount of work completed on each trial. For clinical trial expenses, the significant factors used in estimating accruals include the number of patients enrolled, the number of active clinical sites, and the duration for which the patients will be enrolled in the trial. We monitor patient enrollment levels and related activities to the extent possible through internal reviews, correspondence with CROs and review of contractual terms. We base our estimates on the best information available at the time. However, additional information may become available to us which may allow us to make a more accurate estimate in future periods. In this event, we may be required to record adjustments to research and development expenses in future periods when the actual level of activity becomes more certain. Such increases or decreases in cost are generally considered to be changes in estimates and will be reflected in research and development expenses in the period first known.
Net (Loss) Income Per Share	Net (Loss) Income Per Share
	Basic net (loss) income per share is computed by dividing the net (loss) income for the period by the weighted average number of shares of common stock outstanding during the period. Diluted net (loss) income per share gives effect to potential incremental common shares issuable upon the exercise of stock options and warrants, and shares issuable pursuant to restricted stock units (“RSUs”) (calculated based on the treasury stock method), and upon conversion of our convertible debt (calculated using an as-if-converted method) as long as such shares are not anti-dilutive. The calculation of diluted loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of such securities are dilutive to loss per share for the period, adjustments to net loss used in the calculation are required to remove the change in fair value of the warrants for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares.
Foreign Currency Translation And Remeasurement	Foreign Currency Translation and Remeasurement
	Monetary assets and liabilities denominated in currencies other than the functional currency are remeasured using exchange rates in effect at the end of the period and related gains or losses are recorded in interest income and other, net. Gains and losses on the remeasurement of monetary assets and liabilities were not material for any of the years presented. We do not have any nonmonetary assets or liabilities denominated in currencies other than the U.S. dollar.
Stock-Based Compensation	Stock-Based Compensation
	Stock-based compensation expense for all stock-based compensation awards is based on the grant date fair value estimated using the Black-Scholes Merton option pricing model. Because there is a market for options on our common stock, we have considered implied volatilities as well as our historical realized volatilities when developing an estimate of expected volatility. We estimate the term using historical data and peer data. We recognize compensation expense on a straight-line basis over the requisite service period. Compensation expense relating to awards subject to performance conditions is recognized if it is probable that the performance goals will be achieved. The probability of achievement is assessed on a quarterly basis. The total number of awards expected to vest is adjusted for estimated forfeitures. We have elected to use the simplified method to calculate the beginning pool of excess tax benefits.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 supersedes the revenue recognition requirements of FASB Accounting Standards Codification (“ASC”) Topic 605, Revenue Recognition and most industry-specific guidance throughout the Accounting Standards Codification, resulting in the creation of FASB ASC Topic 606, Revenue from Contracts with Customers. ASU 2014-09 requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. Adoption will be permitted using either a retrospective or modified retrospective approach, and is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is not permitted. We are currently evaluating the impact of adopting this ASU, inclusive of available transitional methods on our consolidated financial statements and related disclosures.
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (“ASU 2014-15”). ASU 2014-15 provides guidance on management’s responsibility in evaluating whether there are conditions or events that raise substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued, and about related footnote disclosures. ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. We are currently evaluating the impact of adopting ASU 2014-15 and its related disclosures.

Organization_And_Summary_Of_Si2

Organization And Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated useful lives of Property and Equipment	Property and equipment are recorded at cost and depreciated using the straight-line method over the following estimated useful lives:
	Equipment and furniture	5 years
	Computer equipment and software	3 years
	Leasehold improvements	Shorter of lease life or 7 years

Restructurings_Tables

Restructurings (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring Charges [Abstract]
Schedule of outstanding restructuring liability	The components and changes of these liabilities since initiation of the 2014 Restructuring are summarized in the following table (in thousands):
		Employee Severance and Other Benefits			Asset Impairment and Other			Total
	Restructuring charge	$	5,775		$	312		$	6,087
	Cash payments	(4,507		)	(77		)	(4,584		)
	Adjustments or non-cash credits	22			(288		)	(266		)
	Proceeds from sale of assets	—			100			100
	Restructuring liability for 2014 Restructuring as of December 31, 2014	$	1,290		$	47		$	1,337
	The components and changes of these liabilities during the year ended December 31, 2014, are summarized in the following table (in thousands):
		Facility			Other			Total
		Charges
	Restructuring liability as of December 31, 2013	$	13,460		$	12		$	13,472
	Restructuring charge (credit)	1,626			(117		)	1,509
	Cash payments	(5,644		)	(8		)	(5,652		)
	Adjustments or non-cash credits	12			(86		)	(74		)
	Proceeds from sale of assets	—			199			199
	Restructuring liability for 2010 Restructurings as of December 31, 2014	$	9,454		$	—		$	9,454

Cash_and_Investments_Tables

Cash and Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-Sale Securities	The following table summarizes cash and cash equivalents, investments, and restricted cash and investments by balance sheet line item as of December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents	$	80,395	$	—	$	—		$	80,395
	Short-term investments	63,988		37		(135		)	63,890
	Short-term restricted cash and investments	12,105		107		—			12,212
	Long-term investments	81,600		1		(22		)	81,579
	Long-term restricted cash and investments	4,684		—		—			4,684
	Total cash and investments	$	242,772	$	145	$	(157	)	$	242,760
		December 31, 2013
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Cash and cash equivalents	$	103,978	$	—	$	—		$	103,978
	Short-term investments	138,403		94		(22		)	138,475
	Short-term restricted cash and investments	12,173		40		—			12,213
	Long-term investments	144,226		106		(33		)	144,299
	Long-term restricted cash and investments	16,837		60		—			16,897
	Total cash and investments	$	415,617	$	300	$	(55	)	$	415,862
Summary of Cash Equivalents and Investments by Security Type	The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):
		December 31, 2014
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Money market funds	$	23,376	$	—	$	—		$	23,376
	Commercial paper	56,714		—		—			56,714
	Corporate bonds	143,444		35		(157		)	143,322
	U.S. Treasury and government sponsored enterprises	12,105		107		—			12,212
	Municipal bonds	2,659		3		—			2,662
	Total investments	$	238,298	$	145	$	(157	)	$	238,286
		December 31, 2013
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	Money market funds	$	24,813	$	—	$	—		$	24,813
	Commercial paper	94,682		—		—			94,682
	Corporate bonds	239,937		190		(55		)	240,072
	U.S. Treasury and government sponsored enterprises	44,284		102		—			44,386
	Municipal bonds	6,005		8					6,013
	Total investments	$	409,721	$	300	$	(55	)	$	409,966
Summary of Available-for-Sale Securities by Contractual Maturity	The following summarizes the fair value of securities classified as available-for-sale by contractual maturity as of December 31, 2014 (in thousands):
		Mature within One Year		After One Year through Two Years		Fair Value
	Money market funds	$	23,376	$	—	$	23,376
	Commercial paper	56,714		—		56,714
	Corporate bonds	134,685		8,637		143,322
	U.S. Treasury and government sponsored enterprises	12,212		—		12,212
	Municipal bonds	2,662		—		2,662
	Total	$	229,649	$	8,637	$	238,286

Inventory_Tables

Inventory (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands):
		December 31,
		2014			2013
	Raw materials	$	1,118		$	529
	Work in process	2,845			2,280
	Finished goods	559			81
	Total	4,522			2,890
	Less: non-current portion included in other assets	(2,141		)	—
	Inventory	$	2,381		$	2,890

Property_And_Equipment_Tables

Property And Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule Of Property And Equipment	Property and equipment consisted of the following (in thousands):
		December 31,
		2014			2013
	Laboratory equipment	$	13,677		$	15,453
	Computer equipment and software	14,840			14,462
	Furniture and fixtures	3,701			3,691
	Leasehold improvements	16,364			17,031
	Construction-in-progress	120			68
		48,702			50,705
	Less: accumulated depreciation and amortization	(46,270		)	(45,795		)
	Property and equipment, net	$	2,432		$	4,910

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule Of Debt	The amortized carrying amount of our debt consists of the following (in thousands):
		December 31,
		2014			2013
	Convertible Senior Subordinated Notes due 2019	$	182,395		$	165,296
	Secured Convertible Notes due 2015	98,880			99,851
	Silicon Valley Bank term loan	80,000			80,000
	Silicon Valley Bank line of credit	381			2,090
	Total debt	361,656			347,237
	Less: current portion	(99,261		)	(11,762		)
	Long-term debt	$	262,395		$	335,475
Summary Of The Liability Component Of The 2019 Notes	The following is a summary of the liability component of the 2019 Notes (in thousands):
		December 31,
		2014			2013
	Net carrying amount of the liability component	$	182,395		$	165,296
	Unamortized discount of the liability component	105,105			122,204
	Principal amount of the 2019 Notes	$	287,500		$	287,500
	The debt discount and debt issuance costs will be amortized as interest expense through August 2019. The following is a summary of interest expense for the 2019 Notes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Stated coupon interest	$	12,253		$	12,219		$	4,582
	Amortization of debt discount and debt issuance costs	17,804			16,201			5,726
	Total interest expense	$	30,057		$	28,420		$	10,308
	The outstanding principal amount of the Deerfield Notes bears interest in the annual amount of $6.0 million, payable quarterly in arrears. The following is a summary of interest expense for the Deerfield Notes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Stated coupon interest	$	6,000		$	6,000		$	6,000
	Amortization of debt discount and debt issuance costs	11,731			10,089			9,913
	Total interest expense	$	17,731		$	16,089		$	15,913
Schedule Of Future Principal Payments Of Total Long-Term Debt	Aggregate expected future principal payments of our debt were as follows as of December 31, 2014 (in thousands):
	Year Ending December 31, (1)
	2015	104,381
	2016	—
	2017	80,000
	2018	—
	2019	287,500
	Thereafter	—
	____________________
	-1	Amounts include principal payments associated with the accretion of discounts and debt issuance costs. For the Deerfield Notes, this table is presented assuming we do not make the election to extend the maturity of those notes and the remaining principal balance will be paid at the current July 2015 maturity date. The actual timing of payments made may differ materially.

Common_Stock_And_Warrants_Tabl

Common Stock And Warrants (Tables)	12 Months Ended
	Dec. 31, 2014
Warrants and Rights Note Disclosure [Abstract]
Schedule Of Warrants To Purchase Common Stock Outstanding And Exercisable	At December 31, 2014, the following warrants to purchase common stock were outstanding and exercisable:
	Date Issued	Exercise		Expiration Date	Number
		Price per Share			of Shares
	January 22, 2014	$	9.7	January 22, 2016	1,000,000

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule Of Fair Value Of Financial Assets Measured On A Recurring Basis	The following table sets forth the fair value of our financial assets and liabilities that were measured and recorded on a recurring basis as of December 31, 2014 and 2013. We did not have any financial liabilities that were measured and recorded on a recurring basis or Level 3 investments as of December 31, 2013. The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):
		December 31, 2014
		Level 1			Level 2			Level 3		Total
	Financial assets:
	Money market funds	$	23,376		$	—		$	—	$	23,376
	Commercial paper	—			56,714			—		56,714
	Corporate bonds	—			143,322			—		143,322
	U.S. Treasury and government sponsored enterprises	—			12,212			—		12,212
	Municipal bonds	—			2,662			—		2,662
	Total financial assets	$	23,376		$	214,910		$	—	$	238,286
	Financial liabilities:
	Warrants	$	—		$	—		$	921	$	921
	Total financial liabilities	$	—		$	—		$	921	$	921
		December 31, 2013
		Level 1			Level 2			Total
	Money market funds	$	24,813		$	—		$	24,813
	Commercial paper	—			94,682			94,682
	Corporate bonds	—			240,072			240,072
	U.S. Treasury and government sponsored enterprises	—			44,386			44,386
	Municipal bonds	—			6,013			6,013
	Total	$	24,813		$	385,153		$	409,966
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following is a reconciliation of changes in the net fair value of warrants which are classified as Level 3 in the fair value hierarchy. There were no transfers into or out of Level 3 during the period presented (in thousands):
		Year Ended December 31,
	Balance at beginning of year	$	—
	Issuance of warrants	2,762
	Unrealized gain included in Interest income and other, net	(1,841		)
	Balance at end of year	$	921
Schedule Of Estimated Fair Value Of Outstanding Debt	The estimated fair value of our financial instruments that are carried at amortized cost for which it is practicable to determine a fair value was as follows (in thousands):
		December 31, 2014						December 31, 2013
		Carrying			Fair Value			Carrying		Fair Value
		Amount						Amount
	2019 Notes	$	182,395		$	156,889		$	165,296	$	339,883
	Silicon Valley Bank Term Loan	$	80,000		$	79,943		$	80,000	$	79,946
	Silicon Valley Bank Line of Credit	$	381		$	381		$	2,090	$	2,090
Schedule Of Assumptions Used	The fair value of the 2014 Deerfield Warrants were estimated using the following assumptions, which, except for risk-free interest rate, are Level 3 inputs (dollars in thousands):
		December 31, 2014			22-Jan-14
					(issuance date)
	Fair value of warrants	$	921		$	2,762
	Risk-free interest rate	1.07		%	0.95		%
	Dividend yield	—		%	—		%
	Volatility	96		%	57		%
	Average expected life	3.1 years			3.2 years

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule Of Allocated Employee Stock-Based Compensation Expense	We recorded and allocated employee stock-based compensation expense for our equity incentive plans and our ESPP as follows (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Research and development expense	$	3,245			$	6,021			$	4,536
	General and administrative expense	6,783				5,948				4,245
	Restructuring-related stock compensation expense (recovery)	(22		)		49				—
	Total employee stock-based compensation expense	$	10,006			$	12,018			$	8,781
Schedule Of Fair Value Of Employee Share-Based Payments Awards Stock Option Assumptions And Weighted Average Fair Values	The fair value of employee stock option awards and ESPP purchases was estimated using the following assumptions and weighted average fair values:
		Stock Options
		2014				2013				2012
	Weighted average grant-date fair value	$	1.46			$	2.97			$	3.24
	Risk-free interest rate	1.8		%		1.51		%		0.81		%
	Dividend yield	—		%		—		%		—		%
	Volatility	85		%		61		%		69		%
	Expected life	5.5 years				5.6 years				5.6 years
Schedule Of Fair Value Of Employee Share-Based Payments Awards ESPP Assumptions And Weighted Average Fair Values
		ESPP
		2014				2013				2012
	Weighted average grant-date fair value	$	1.28			$	1.64			$	2.07
	Risk-free interest rate	0.06		%		0.11		%		0.1		%
	Dividend yield	—		%		—		%		—		%
	Volatility	69		%		66		%		68		%
	Expected life	6 months				6 months				6 months
Summary Of All Stock Option Activity	A summary of all option activity was as follows for the periods presented (dollars in thousands, except per share amounts):
		Shares			Weighted				Weighted		Aggregate
					Average				Average		Intrinsic
					Exercise Price				Remaining		Value
									Contractual
									Term
	Options outstanding at December 31, 2011	17,436,378			$	7.16
	Granted	3,442,696			$	5.45
	Exercised	(181,979	)		$	5.09
	Forfeited	(358,360	)		$	5.88
	Expired	(1,890,185	)		$	7.54
	Options outstanding at December 31, 2012	18,448,550			$	6.85
	Granted	6,694,174			$	5.44
	Exercised	(13,311	)		$	5.06
	Forfeited	(79,942	)		$	5.27
	Expired	(1,066,196	)		$	6.45
	Options outstanding at December 31, 2013	23,983,275			$	6.48
	Granted	10,038,565			$	2.11
	Exercised	(19,090	)		$	6.28
	Forfeited	(4,650,543	)		$	5.34
	Expired	(1,540,215	)		$	8.06
	Options outstanding at December 31, 2014	27,811,992			$	5			4.21 years		$	20
	Exercisable at December 31, 2014	15,403,813			$	6.75			2.57 years		$	—
Summary Of Information About Stock Options Outstanding	The following table summarizes information about stock options outstanding and exercisable at December 31, 2014:
		Options Outstanding									Options Outstanding and
											Exercisable
	Exercise Price Range	Number			Weighted		Weighted				Number of		Weighted
					Average		Average				Exercisable		Average
					Remaining		Exercise						Exercise
					Contractual Life		Price						Price
	$1.46 - $1.70	8,430,075			6.64 years		$	1.7			—
	$1.76 - $5.50	4,880,183			3.63 years		$	4.78			3,935,186		$	4.98
	$5.51 - $5.60	4,344,546			4.76 years		$	5.52			1,628,954		$	5.53
	$5.61 - $5.92	3,397,550			1.99 years		$	5.69			3,335,913		$	5.69
	$5.94 - $8.90	4,209,035			2.48 years		$	7.92			3,953,157		$	7.96
	$8.99 - $12.10	2,550,603			2.16 years		$	9.73			2,550,603		$	9.73
		27,811,992			4.21 years		$	5			15,403,813		$	6.75
Summary Of All RSU Activity	A summary of all RSU activity was as follows for all periods presented (dollars in thousands, except per share amounts):
		Shares			Weighted				Weighted		Aggregate
					Average				Average		Intrinsic
					Grant Date				Remaining		Value
					Fair Value				Contractual
									Term
	Awards outstanding at December 31, 2011	1,391,691			$	6.92
	Awarded	733,958			$	5.5
	Released	(596,397	)		$	7.15
	Forfeited	(234,631	)		$	6.62
	Awards outstanding at December 31, 2012	1,294,621			$	6.07
	Awarded	1,119,733			$	5.45
	Released	(517,874	)		$	6.6
	Forfeited	(85,959	)		$	5.49
	Awards outstanding at December 31, 2013	1,810,521			$	5.56
	Awarded	559,659			$	1.94
	Released	(459,939	)		$	4.96
	Forfeited	(948,772	)		$	5.48
	Awards outstanding at December 31, 2014	961,469			$	3.82			1.88 years		$	1,586

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule Of Consolidated Net Income (Loss)	The income tax (benefit) provision is based on the following loss before income taxes (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Domestic	$	(237,780	)	$	(236,076	)	$	(147,538	)
	Foreign	(30,944		)	(8,780		)	—
	Total	$	(268,724	)	$	(244,856	)	$	(147,538	)
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense (benefit) consists of the following for the periods shown below (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Current:
	Federal	$	—		$	—		$	32
	State	(182		)	12			75
	Total current tax expense	(182		)	12			107
	Deferred:
	Federal	—			(106		)	—
	State	—			(2		)	—
	Total deferred tax expense	—			(108		)	—
	Income tax (benefit) provision	$	(182	)	$	(96	)	$	107
Schedule Of Reconciliation Of Income Taxes At The Statutory Federal Income Tax Rate To Net Income Taxes	A reconciliation of income taxes at the statutory federal income tax rate to our income tax (benefit) provision included in the Consolidated Statements of Operations is as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	U.S. federal income tax (benefit) provision at statutory rate	$	(91,366	)	$	(83,251	)	$	(50,163	)
	Unutilized net operating losses	87,448			(3,438		)	46,324
	Non-deductible interest	3,598			3,380			3,297
	Stock-based compensation	255			393			504
	State tax expense	(182		)	10			74
	Refundable tax credit	—			—			32
	Available-for-sale investments	—			(106		)	—
	Impact of intellectual property rights transfer	—			82,858			—
	Other	65			58			39
	Income tax (benefit) provision	$	(182	)	$	(96	)	$	107
Schedule Of Deferred Assets And Liabilities	Our deferred tax assets and liabilities consist of the following (in thousands):
		December 31,
		2014			2013
	Deferred tax assets:
	Net operating loss carry-forwards	$	446,343		$	358,372
	Tax credit and charitable contribution carry-forwards	64,368			64,635
	Amortization of deferred stock compensation – non-qualified	27,500			24,279
	Accruals and reserves not currently deductible	6,521			10,107
	Deferred revenue	988			502
	Book over tax depreciation and amortization	5,118			4,499
	Total deferred tax assets	550,838			462,394
	Valuation allowance	(511,171		)	(421,426		)
	Net deferred tax assets	39,667			40,968
	Deferred tax liabilities:
	Unrealized gain on derivatives	(704		)	—
	Convertible debt	(38,963		)	(40,968		)
	Total deferred tax liabilities	(39,667		)	(40,968		)
	Net deferred taxes	$	—		$	—
Schedule Of Unrecognized Tax Benefits	The following table summarizes the activity related to our unrecognized tax benefits for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Beginning balance	$	55,077		$	47,298		$	39,310
	Increase (decrease) relating to prior year provision	719			(112		)	5,894
	Increase relating to current year provision	2,706			7,891			2,094
	Reductions based on the lapse of the applicable statutes of limitations	(287		)	—			—
	Ending balance	$	58,215		$	55,077		$	47,298

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule Of Reconciliation Of Basic And Diluted Net Income (Loss) Per Share	The following table sets forth a reconciliation of basic and diluted net loss per share (in thousands, except per share amounts):
		Year Ended December 31,
		2014				2013			2012
	Numerator:
	Net loss	$	(268,542	)		$	(244,760	)	$	(147,645	)
	Denominator:
	Shares used in computing basic and diluted net loss per share	194,299				184,062			160,138
	Net loss per share, basic and diluted	$	(1.38	)		$	(1.33	)	$	(0.92	)
Schedule Of Potential Shares Of Common Stock Not Included In Computation Of Diluted Net Loss Per Share	The following table sets forth outstanding potential shares of common stock outstanding as of dates presented that are not included in the computation of diluted net loss per share because to do so would be anti-dilutive (in thousands):
		December 31,
		2014			2013			2012
	Convertible debt	75,734			54,123			54,123
	Outstanding stock options, unvested RSUs and ESPP contributions	28,930			21,401			16,568
	Warrants	1,000			1,441			1,441
	Total potentially dilutive shares	105,664			76,965			72,132

Commitments_Tables

Commitments (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule Of Aggregate Future Minimum Lease Payments Under Operating Leases	Aggregate future minimum lease payments under our operating leases are as follows (in thousands):
	Year Ending December 31,	Operating
		Leases (1)
	2015	$	20,152
	2016	16,431
	2017	9,104
	2018	2,806
	Thereafter	—
		$	48,493
	____________________
	-1	Minimum payments have not been reduced by minimum sublease rentals of $9.2 million due in the future under noncancelable subleases.
Schedule Of Aggregate Future Minimum Lease Payments Under Operating Leases By Material Lease Agreements	The following is a summary of aggregate future minimum lease payments under operating leases at December 31, 2014, by operating lease agreements (in thousands):
		Original	Renewal Options	Future
		Term		Minimum
		(Expiration)		Lease
				Payments
	Building Lease #1 and 2	May-17	2 additional periods of 5 years	$	27,556
	Building Lease #3	Jul-18	1 additional period of 5 years	16,660
	Building Lease #4	Dec-15	1 additional period of 3 years	4,211
	Other			66
	Total			$	48,493

Concentrations_of_Credit_Risk_

Concentrations of Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2014
Risks and Uncertainties [Abstract]
Schedules of collaborators that represent 10% or more of total revenues	The following table shows the percentage of revenues earned in the United States and the European Union.
		Year Ended December 31,
		2014		2013		2012
	Percentage of revenues earned in the United States	99	%	97	%	100	%
	Percentage of revenues earned in the European Union	1	%	3	%	—	%
	The following table sets forth the percentage of revenues recognized under our collaboration agreements and product sales to the specialty pharmacy that represent 10% or more of total revenues:
		Year Ended December 31,
		2014		2013		2012
	Product sales:
	Diplomat Specialty Pharmacy	99	%	45	%	—	%
	Collaboration agreement:
	Bristol-Myers Squibb	—	%	52	%	66	%
	Merck	—	%	—	%	22	%
	Daiichi Sankyo	—	%	—	%	12	%

Quarterly_Financial_Data_Unaud1

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule Of Quarterly Financial Data	The following tables summarize the unaudited quarterly financial data for the last two fiscal years (in thousands, except per share data):
		Quarter Ended
		December 31,			September 30,			June 30,			March 31,
	2014:00:00
	Revenues	$	7,353		$	6,291		$	6,562		$	4,905
	Gross profit	$	6,669		$	5,718		$	6,085		$	4,596
	Loss from operations	$	(46,208	)	$	(51,574	)	$	(61,688	)	$	(64,988	)
	Net loss	$	(57,953	)	$	(62,560	)	$	(73,410	)	$	(74,619	)
	Net loss per share, basic and diluted	$	(0.30	)	$	(0.32	)	$	(0.38	)	$	(0.39	)
	2013:00:00
	Revenues	$	4,347		$	5,466		$	11,856		$	9,669
	Gross profit	$	4,084		$	5,176		$	11,571		$	9,389
	Loss from operations	$	(59,514	)	$	(55,913	)	$	(51,295	)	$	(34,010	)
	Net loss	$	(70,746	)	$	(67,124	)	$	(62,161	)	$	(44,729	)
	Net loss per share, basic and diluted	$	(0.38	)	$	(0.36	)	$	(0.34	)	$	(0.24	)

Organization_And_Summary_Of_Si3

Organization And Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended			24 Months Ended	12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2015
	phase								segment			phase
	trial								phase			trial
									trial
Organization And Summary Of Significant Policies [Line Items]
Number of trials in process	45								45			45
Number of phase 3 trials in process	2								2			2
Annual operating cycle									371 days	364 days	364 days
Number of Operating Segments									1
Net (loss) income	($57,953,000)	($62,560,000)	($73,410,000)	($74,619,000)	($70,746,000)	($67,124,000)	($62,161,000)	($44,729,000)	($268,542,000)	($244,760,000)	($147,645,000)
Accumulated deficit	-1,767,304,000				-1,498,762,000				-1,767,304,000	-1,498,762,000		-1,767,304,000
Net product revenues									25,111,000	15,017,000	0	40,100,000
Cash, Cash Equivalents, and Available-for-sale Securities	242,760,000				415,862,000				242,760,000	415,862,000		242,760,000
Cash, Cash Equivalents, and Short-term Investments	144,300,000								144,300,000			144,300,000
Short-term restricted cash and investments	12,212,000				12,213,000				12,212,000	12,213,000		12,212,000
Long-term investments	81,579,000				144,299,000				81,579,000	144,299,000		81,579,000
Long-term restricted cash and investments	4,684,000				16,897,000				4,684,000	16,897,000		4,684,000
Percent of revenue recognized on achievement of contingency	100.00%								100.00%			100.00%
Percent discount for prompt payment									2.00%
Amount of reduction relating to prior periods										800,000	2,700,000
GlaxoSmithKline [Member]
Organization And Summary Of Significant Policies [Line Items]
Percent of royalty on net sale									3.00%
Secured Convertible Notes Due June 2015 [Member] | Deerfield Financing [Member]
Organization And Summary Of Significant Policies [Line Items]
Principal Eligible for Extension Option	$100,000,000								$100,000,000			$100,000,000
Subsequent Event [Member]
Organization And Summary Of Significant Policies [Line Items]
Annual operating cycle													364 days
Minimum [Member]
Organization And Summary Of Significant Policies [Line Items]
Annual operating cycle									364 days
Maximum [Member]
Organization And Summary Of Significant Policies [Line Items]
Annual operating cycle									371 days

Organization_And_Summary_Of_Si4

Organization And Summary Of Significant Accounting Policies (Estimated Useful Lives Of Property Plant And Equipment) (Details)	12 Months Ended
	Dec. 31, 2014
Equipment And Furniture [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives, years	P5Y
Computer Equipment And Software [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives, years	P3Y
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives, years	P7Y

Research_And_Collaboration_Agr1

Research And Collaboration Agreements (Cobimetinib Collaboration To Bristol-Meyers Squibb) (Details) (USD $)

12 Months Ended

1 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2010

Mar. 31, 2008

Jan. 31, 2007

Dec. 31, 2006

Jul. 31, 2011

Nov. 30, 2010

Jan. 31, 2010

Jan. 31, 2009

Dec. 31, 2007

Dec. 31, 2005

product

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum Potential Milestone Payments

$2,300,000,000

Percentage of Maximum Potential Milestone Payments - Clinical Development

10.00%

Percentage of Maximum Potential Milestone Payments - Regulatory

42.00%

Percentage of Maximum Potential Milestone Payments - Commercial

48.00%

License and contract revenues

0

16,321,000

47,450,000

Genentech [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront and milestone payments

15,000,000

25,000,000

Payment to use exercise of option related to co-development agreement

3,000,000

Milestone payment

7,000,000

Optional percent of total sales

25.00%

Genentech [Member] | Profit Sharing Tier One [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Percent of profits

50.00%

Profit threshold

200,000,000

Genentech [Member] | Profit Sharing Tier Two [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Percent of profits

30.00%

Profit threshold

400,000,000

Bristol-Myers Squibb [Member] | ROR Collaboration Agreement [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront cash payment

5,000,000

Maximum amount eligible for development and regulatory milestones

252,500,000

Income from development milestone

2,500,000

License and contract revenues

0

1,500,000

2,900,000

Bristol-Myers Squibb [Member] | TGR5 License Agreement [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum amount eligible for commercial milestones under collaborations agreement

150,000,000

Bristol-Myers Squibb [Member] | LXR Collaboration [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront cash payment

17,500,000

Maximum amount eligible for development and regulatory milestones

138,000,000

Income from development milestone

5,000,000

License and contract revenues

0

0

0

Research and development fund

5,800,000

10,000,000

Number of years for initial research

2 years

Number of products

2

Maximum amount eligible for royalties on sales under collaborations agreement

225,000,000

Additional research fund

7,700,000

Bristol-Myers Squibb [Member] | Terminated Collaborations [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

License and contract revenues

$0

$14,800,000

$28,400,000

Research_And_Collaboration_Agr2

Research And Collaboration Agreements (Sanofi To GlaxoSmithKline) (Details) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 20, 2009	Jan. 31, 2012	Aug. 31, 2012	Dec. 31, 2010	Jun. 30, 2007	Mar. 31, 2006	Oct. 31, 2002
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and contract revenues	$0	$16,321,000	$47,450,000
Purchase an aggregate shares of common stock	195,895,769	184,533,651
Sanofi [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront and milestone payments				140,000,000
Upfront payment received for license				120,000,000
Upfront payment received for collaboration				20,000,000
Withholding taxes on upfront payments				7,000,000
Upfront payments, net of tax				133,000,000
Maximum amount eligible for development and regulatory milestones	745,000,000
Proceeds from termination of agreement					15,300,000
License and contract revenues	0	0	0
Merck [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum amount eligible for development and regulatory milestones	239,000,000
License and contract revenues	0	0	10,700,000
Upfront cash payment					12,000,000
Maximum amount eligible for royalties on sales under collaborations agreement	375,000,000
Daiichi Sankyo [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum amount eligible for development and regulatory milestones	145,000,000
License and contract revenues	0	0	5,500,000
Upfront cash payment									20,000,000
Research and development fund								1,500,000	3,800,000
Original research term, years									15 months
Extended research term, years								6 months
Milestone payment						5,500,000	5,000,000
GlaxoSmithKline [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront and milestone payments										65,000,000
License and contract revenues	0	0	0
Research and development funding and loans										85,000,000
Purchase an aggregate shares of common stock										3,000,000
Royalty expense	$700,000	$400,000
GlaxoSmithKline [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percent of royalty on net sales	3.00%

Disposition_of_Artemis_Pharmac1

Disposition of Artemis Pharmaceuticals (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2011	Nov. 30, 2007
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business	$838,000	$0	$0
Artemis Pharmaceuticals GmbH [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Outstanding share capital of wholly-owned subsidiary sold					19.90%	80.10%
Proceeds from sale of business				800,000
Gain on sale of business				$800,000

Restructurings_Narrative_Detai

Restructurings (Narrative) (Details) (USD $)	12 Months Ended			39 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	31-May-13
	employee			restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$7,596,000	$1,231,000	$9,171,000
2014 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Expected number of remaining positions	80
Restructuring charges	6,087,000
Restructuring reserve	1,337,000
2014 Restructuring [Member] | One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Expected additional payment for restructuring	6,000,000
Expected restructuring cost, percentage in current fiscal year	95.00%
2014 Restructuring [Member] | Employee Severance And Other Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5,775,000
Restructuring reserve	1,290,000
2014 Restructuring [Member] | Asset Impairment And Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	312,000
Restructuring reserve	47,000
2010 Restructurings [Member]
Restructuring Cost and Reserve [Line Items]
Expected additional payment for restructuring	800,000
Restructuring charges	1,509,000	1,200,000	9,200,000
Number of restructurings implemented				5
Aggregate reduction in headcount	429
Restructuring reserve	9,454,000	13,472,000
2010 Restructurings [Member] | Facility Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,626,000
Restructuring reserve	9,454,000	13,460,000
Capital Leases, Future Minimum Sublease Rentals	9,100,000
2010 Restructurings [Member] | Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	-100,000
Minimum [Member] | 2014 Restructuring [Member] | Facility Charges [Member]
Restructuring Cost and Reserve [Line Items]
Expected additional payment for restructuring	2,000,000
Maximum [Member] | 2014 Restructuring [Member] | Facility Charges [Member]
Restructuring Cost and Reserve [Line Items]
Expected additional payment for restructuring	$6,000,000

Restructurings_Schedule_Of_Out

Restructurings (Schedule Of Outstanding Restructuring Liability) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Restructuring charges	$7,596	$1,231	$9,171
2014 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	6,087
Cash payments	-4,584
Adjustments or non-cash credits including stock compensation expense	-266
Proceeds from sale of assets	100
Ending accrual balance at end of period	1,337
2014 Restructuring [Member] | Employee Severance And Other Benefits [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	5,775
Cash payments	-4,507
Adjustments or non-cash credits including stock compensation expense	22
Proceeds from sale of assets	0
Ending accrual balance at end of period	1,290
2014 Restructuring [Member] | Asset Impairment And Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	312
Cash payments	-77
Adjustments or non-cash credits including stock compensation expense	-288
Proceeds from sale of assets	100
Ending accrual balance at end of period	47
2010 Restructurings [Member]
Restructuring Reserve [Roll Forward]
Ending accrual balance at beginning of period	13,472
Restructuring charges	1,509	1,200	9,200
Cash payments	-5,652
Adjustments or non-cash credits including stock compensation expense	-74
Proceeds from sale of assets	199
Ending accrual balance at end of period	9,454	13,472
2010 Restructurings [Member] | Facility Charges [Member]
Restructuring Reserve [Roll Forward]
Ending accrual balance at beginning of period	13,460
Restructuring charges	1,626
Cash payments	-5,644
Adjustments or non-cash credits including stock compensation expense	12
Proceeds from sale of assets	0
Ending accrual balance at end of period	9,454
2010 Restructurings [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Ending accrual balance at beginning of period	12
Restructuring charges	-117
Cash payments	-8
Adjustments or non-cash credits including stock compensation expense	-86
Proceeds from sale of assets	199
Ending accrual balance at end of period	$0

Cash_and_Investments_Details

Cash and Investments (Details) (USD $)	1 Months Ended	12 Months Ended
	Jun. 30, 2010	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
	affiliate	affiliate
		account
		investment
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$242,772,000		$415,617,000
Gross Unrealized Gains		145,000		300,000
Gross Unrealized Losses		-157,000		-55,000
Fair Value		242,760,000		415,862,000
Number of required investment accounts		1
Number of affiliate banks	1	1
Amortized Cost		238,298,000		409,721,000
Gross Unrealized Gains		145,000		300,000
Gross Unrealized Losses		-157,000		-55,000
Fair Value		238,286,000		409,966,000
Gain (Loss) on Sale of Investments		0	0
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year		40
Unrealized loss position		82,800,000
Silicon Valley Bank Loan And Security Agreement [Member]
Schedule of Available-for-sale Securities [Line Items]
Compensating Balance, Amount		82,000,000		83,700,000
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		23,376,000		24,813,000
Gross Unrealized Gains		0		0
Gross Unrealized Losses		0		0
Fair Value		23,376,000		24,813,000
Mature within One Year		23,376,000
After One Year through Two Years		0
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		56,714,000		94,682,000
Gross Unrealized Gains		0		0
Gross Unrealized Losses		0		0
Fair Value		56,714,000		94,682,000
Mature within One Year		56,714,000
After One Year through Two Years		0
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		143,444,000		239,937,000
Gross Unrealized Gains		35,000		190,000
Gross Unrealized Losses		-157,000		-55,000
Fair Value		143,322,000		240,072,000
Mature within One Year		134,685,000
After One Year through Two Years		8,637,000
U.S. Treasury and government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		12,105,000		44,284,000
Gross Unrealized Gains		107,000		102,000
Gross Unrealized Losses		0		0
Fair Value		12,212,000		44,386,000
Mature within One Year		12,212,000
After One Year through Two Years		0
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,659,000		6,005,000
Gross Unrealized Gains		3,000		8,000
Gross Unrealized Losses		0
Fair Value		2,662,000		6,013,000
Mature within One Year		2,662,000
After One Year through Two Years		0
Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		80,395,000		103,978,000
Gross Unrealized Gains		0		0
Gross Unrealized Losses		0		0
Fair Value		80,395,000		103,978,000
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		63,988,000		138,403,000
Gross Unrealized Gains		37,000		94,000
Gross Unrealized Losses		-135,000		-22,000
Fair Value		63,890,000		138,475,000
Short-term restricted cash and investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		12,105,000		12,173,000
Gross Unrealized Gains		107,000		40,000
Gross Unrealized Losses		0		0
Fair Value		12,212,000		12,213,000
Long-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		81,600,000		144,226,000
Gross Unrealized Gains		1,000		106,000
Gross Unrealized Losses		-22,000		-33,000
Fair Value		81,579,000		144,299,000
Long-term restricted cash and investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		4,684,000		16,837,000
Gross Unrealized Gains		0		60,000
Gross Unrealized Losses		0		0
Fair Value		4,684,000		16,897,000
Investments, excluding cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value		238,286,000
Mature within One Year		229,649,000
After One Year through Two Years		$8,637,000

Inventory_Details

Inventory (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$1,118	$529
Work in process	2,845	2,280
Finished goods	559	81
Total	4,522	2,890
Less: non-current portion included in other assets	-2,141	0
Inventory	2,381	2,890
Inventory write-down	$200	$39

Property_And_Equipment_Schedul

Property And Equipment (Schedule Of Property And Equipment) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Laboratory equipment	$13,677	$15,453
Computer equipment and software	14,840	14,462
Furniture and fixtures	3,701	3,691
Leasehold improvements	16,364	17,031
Construction-in-progress	120	68
Property and equipment, gross	48,702	50,705
Less: accumulated depreciation and amortization	-46,270	-45,795
Property and equipment, net	$2,432	$4,910

Property_And_Equipment_Narrati

Property And Equipment (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciation	$2,300,000	$3,100,000	$4,800,000
Impairment charges	700,000	100,000	300,000
Gain on sale of assets	600,000	0	300,000
Asset Impairment [Member]
Property, Plant and Equipment [Line Items]
Restructuring Reserve, Proceeds from Sale of Property, Plant, and Equipment	$400,000	$100,000	$900,000

Debt_Schedule_Of_Debt_Details

Debt (Schedule Of Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Total debt	$361,656	$347,237
Less: current portion	-99,261	-11,762
Long-term debt	262,395	335,475
Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Debt Instrument [Line Items]
Convertible Debt	182,395	165,296
Secured Debt [Member] | Secured Convertible Notes due June 2015 [Member]
Debt Instrument [Line Items]
Convertible Debt	98,880	99,851
Term Loan [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Silicon Valley Bank term loan	80,000	80,000
Line of Credit [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Silicon Valley Bank Line of Credit	$381	$2,090

Debt_Narrative_Details

Debt (Narrative) (Details) (USD $)	0 Months Ended	1 Months Ended				12 Months Ended			0 Months Ended	1 Months Ended
	Aug. 14, 2012	Jan. 31, 2014	Aug. 31, 2012	Feb. 29, 2012	Jun. 30, 2010	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 22, 2014	Jan. 31, 2013	Dec. 31, 2007	Aug. 06, 2012
					affiliate	account
						affiliate
Debt Instrument [Line Items]
Sale of shares of common stock, shares		10,000,000	34,500,000	12,700,000
Share price (dollars per share)		$8	$4.25	$5.17
Proceeds from Issuance of Common Stock and Convertible Debt, Net	$416,100,000
Proceeds from Convertible Debt, Net	277,700,000
Proceeds from Issuance of Common Stock		75,600,000	138,400,000	65,000,000		75,643,000	0	203,479,000
Short-term restricted cash and investments						12,212,000	12,213,000
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	4,900,000							137,785,000
Book value of debt outstanding						361,656,000	347,237,000
Number of required investment accounts						1
Number of affiliate banks					1	1
Minimum [Member]
Debt Instrument [Line Items]
Number of required investment accounts					1
Warrants Issued On January 22, 2014 [Member]
Debt Instrument [Line Items]
Warrants outstanding						1,000,000			1,000,000
Exercise Price per Share (in dollars per share)						$9.70			9.7
Warrant repricing terms on exercise of extension option									120.00%
Warrants Issued On January Twenty Two Two Thousand and Fourteen[Member] [Member]
Debt Instrument [Line Items]
Warrant repricing terms on exercise of extension option									120.00%
Debt Instrument, Term									2 years
Warrants, Percentage Of Shares Exceeded									9.98%
Debt Payment [Member]
Debt Instrument [Line Items]
Restricted Cash and Investments	36,500,000
Restricted Cash and Investments Used for Debt Payments						24,500,000
Silicon Valley Bank Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Debt, interest rate						6.00%
Compensating Balance, Amount						82,000,000	83,700,000
Silicon Valley Bank Loan And Security Agreement [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Book value of debt outstanding						80,400,000	82,100,000
Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Debt Instrument [Line Items]
Debt, principal amount			287,500,000			287,500,000	287,500,000
Debt, interest rate	4.25%
Debt Instrument, Redemption Price Component, Percentage of Principal	100.00%
Debt Instrument, Convertible, Conversion Ratio	0.1882353					188.2353
Debt Instrument, Convertible, Conversion Ratio, Principal Amount	1,000
Debt Instrument, Convertible, Conversion Price (dollars per share)	$5.31
Debt Instrument, Periodic Payment, Number of Payments Secured in Escrow	6
Debt Instrument, Interest Rate, Effective Percentage	10.09%
Debt Instrument, Fair Value Disclosure	144,300,000
Debt Instrument, Unamortized Discount	143,200,000
Unamortized debt issuance expense						105,105,000	122,204,000
Balance of unamortized closing fees and expenses						3,300,000	4,000,000
Convertible Debt						182,395,000	165,296,000
Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member] | Other Noncurrent Assets [Member]
Debt Instrument [Line Items]
Unamortized debt issuance expense	4,900,000
Secured Convertible Notes Due June 2015 [Member] | Deerfield Financing [Member]
Debt Instrument [Line Items]
Debt, principal amount					124,000,000
Balance of unamortized closing fees and expenses						1,400,000	1,400,000
Debt instruments, purchase price					80,000,000
Debt instruments, closing fees and expenses					2,000,000
Convertible Debt						104,000,000	114,000,000
Annual interest					6,000,000
Debt Instrument, Amendment, Consent Fee, Amount												1,500,000
Principal Eligible for Extension Option						100,000,000
Debt Instrument, Interest Rate, Stated Percentage after Extension Option Election									15.00%
Repayments of Notes Payable		10,000,000								10,000,000,000
Percentage of revenues payable under collaborative arrangements in 2013, 2014 and 2015						15.00%
Maximum prepayment amount under collaborative arrangements in 2013 and 2014						27,500,000
Prepayment Price									105.00%
Debt instrument, minimum purchase amount for prepayment condition						400,000,000
Percentage of assets minimum for prepayment condition						50.00%
Line of Credit [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Annual rate of interest											0.75%
Silicon Valley Bank Line of Credit						381,000	2,090,000
Seven-Year Term Loan [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Debt Instrument [Line Items]
Debt, principal amount					80,000,000
Debt, interest rate					1.00%
Debt Instrument, Number of Balloon Payments					1
Principal balance payable in balloon payment					100.00%
Percentage of security deposit on outstanding obligations					100.00%
Minimum percentage required for collateral balance						1
Maximum percentage required for collateral balance						1.07
Underwriting Discount [Member]
Debt Instrument [Line Items]
Payments of Debt Issuance Costs	9,300,000
Payments of stock issuance costs	7,700,000
Other Costs [Member]
Debt Instrument [Line Items]
Payments of Debt Issuance Costs	500,000
Payments of stock issuance costs	$500,000
Coupon Interest [Member] | Secured Convertible Notes Due June 2015 [Member] | Deerfield Financing [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage after Extension Option Election									7.50%
Payment-in-Kind Interest [Member] | Secured Convertible Notes Due June 2015 [Member] | Deerfield Financing [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage after Extension Option Election									7.50%

Debt_Schedule_of_2019_and_2010

Debt (Schedule of 2019 and 2010 Notes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 31, 2012	Jun. 30, 2010
Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Debt Instrument [Line Items]
Net carrying amount of the liability component	$182,395,000	$165,296,000
Unamortized discount of the liability component	105,105,000	122,204,000
Principal amount of the 2019 Notes	287,500,000	287,500,000		287,500,000
Stated coupon interest	12,253,000	12,219,000	4,582,000
Amortization of debt discount and debt issuance costs	17,804,000	16,201,000	5,726,000
Total interest expense	30,057,000	28,420,000	10,308,000
Secured Convertible Notes Due June 2015 [Member] | Deerfield Financing [Member]
Debt Instrument [Line Items]
Net carrying amount of the liability component	104,000,000	114,000,000
Principal amount of the 2019 Notes					124,000,000
Stated coupon interest	6,000,000	6,000,000	6,000,000
Amortization of debt discount and debt issuance costs	11,731,000	10,089,000	9,913,000
Total interest expense	$17,731,000	$16,089,000	$15,913,000

Debt_Schedule_Of_Future_Princi

Debt (Schedule Of Future Principal Payments Of Total Long-Term Debt) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$104,381	[1]
2016	0	[1]
2017	80,000	[1]
2018	0	[1]
2019	287,500	[1]
Thereafter	$0	[1]
[1]	Amounts include principal payments associated with the accretion of discounts and debt issuance costs. For the Deerfield Notes, this table is presented assuming we do not make the election to extend the maturity of those notes and the remaining principal balance will be paid at the current July 2015 maturity date. The actual timing of payments made may differ materially.

Common_Stock_And_Warrants_Narr

Common Stock And Warrants (Narrative) (Details) (USD $)	1 Months Ended			12 Months Ended			0 Months Ended
	Jan. 31, 2014	Aug. 31, 2012	Feb. 29, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 22, 2014	Jan. 22, 2014
Class of Warrant or Right [Line Items]
Public offering of common stock	10,000,000	34,500,000	12,700,000
Share price (dollars per share)	$8	$4.25	$5.17
Net proceeds from public offering	$75,600,000	$138,400,000	$65,000,000	$75,643,000	$0	$203,479,000
Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Class of Warrant or Right [Line Items]
Debt, principal amount		287,500,000		287,500,000	287,500,000
Warrants Issued On January 22, 2014 [Member]
Class of Warrant or Right [Line Items]
Exercise Price per Share (in dollars per share)				$9.70			$9.70	$9.70
Warrant period							2 years	2 years
Warrant repricing terms on exercise of extension option							120.00%	120.00%
Fair Value of warrants				900,000			2,800,000	2,800,000
Unrealized Gain (Loss) on Derivatives				$1,800,000

Common_Stock_And_Warrants_Sche

Common Stock And Warrants (Schedule Of Warrants To Purchase Common Stock Outstanding And Exercisable) (Details) (Warrants Issued On January 22, 2014 [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Jan. 22, 2014
Warrants Issued On January 22, 2014 [Member]
Class of Warrant or Right [Line Items]
Exercise Price per Share (in dollars per share)	$9.70	$9.70
Expiration Date	22-Jan-16
Number of Shares	1,000,000	1,000,000

Fair_Value_Measurements_Schedu

Fair Value Measurements (Schedule Of Fair Value Of Financial Assets Measured On A Recurring Basis) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	$238,286	$409,966
Warrants	921
Total financial liabilities	921
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	23,376	24,813
Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	56,714	94,682
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	143,322	240,072
U.S. Treasury and government sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	12,212	44,386
Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	2,662	6,013
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	23,376	24,813
Warrants	0
Total financial liabilities	0
Level 1 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	23,376	24,813
Level 1 [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 1 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 1 [Member] | U.S. Treasury and government sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 1 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	214,910	385,153
Warrants	0
Total financial liabilities	0
Level 2 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 2 [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	56,714	94,682
Level 2 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	143,322	240,072
Level 2 [Member] | U.S. Treasury and government sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	12,212	44,386
Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	2,662	6,013
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0
Warrants	921	0
Total financial liabilities	921
Fair Value, Inputs, Level 3 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0
Fair Value, Inputs, Level 3 [Member] | Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0
Fair Value, Inputs, Level 3 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0
Fair Value, Inputs, Level 3 [Member] | U.S. Treasury and government sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0
Fair Value, Inputs, Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	$0

Fair_Value_Measurements_Fair_V

Fair Value Measurements (Fair Value Schedule of Level 3 Changes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Warrants	921,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Warrants	0
Issuance of warrants	2,762,000
Unrealized gain included in Interest income and other, net	-1,841,000
Warrants	$921,000

Fair_Value_Measurements_Schedu1

Fair Value Measurements (Schedule of Estimated Fair Value of Outstanding Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Carrying Amount [Member] | Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	$182,395	$165,296
Carrying Amount [Member] | Term Loan [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	80,000	80,000
Carrying Amount [Member] | Line of Credit [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	381	2,090
Fair Value [Member] | Senior Subordinated Notes [Member] | Convertible Senior Subordinated Notes due August 15, 2019, 4.25% [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	156,889	339,883
Fair Value [Member] | Term Loan [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	79,943	79,946
Fair Value [Member] | Line of Credit [Member] | Silicon Valley Bank Loan And Security Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument	$381	$2,090

Fair_Value_Measurements_Schedu2

Fair Value Measurements (Schedule of Assumptions) (Details) (Warrants Issued On January 22, 2014 [Member], USD $)	0 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Jan. 22, 2014	Jan. 22, 2014	Dec. 31, 2014
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Warrant period	2 years	2 years
Warrant Liability [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value of warrants	2,762	2,762	$921
Risk-free interest rate		0.95%	1.07%
Dividend yield		0.00%	0.00%
Volatility		57.00%	96.00%
Average expected life		3 years 2 months 12 days	3 years 1 month 6 days

Employee_Benefit_Plans_Narrati

Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$10,006,000	$12,018,000	$8,781,000
Fair value of employee options vested and expensed	8,600,000	7,400,000	5,600,000
Options outstanding (in shares)	27,811,992	23,983,275	18,448,550	17,436,378
Options cancelled (in shares)	4,650,543	79,942	358,360
Cash received from option exercises and purchases under the ESPP	1,600,000	1,500,000
Retirement Plan, employee contribution (percentage)	50.00%
Employer matching contributions for first 4% of participant contributions	50.00%
Percentage of company contribution to participant's compensation	4.00%
Employer matching contributions for first 3% of participant contributions	100.00%
Percentage of participant contributions into the 401(k) Retirement Plan	3.00%
Expenses relating to stock match	1,100,000	800,000	600,000
Non Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	100,000		0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	4 years
Life of stock options granted (years)	P7Y		P10Y
Number of shares available for grant	11,470,066
Intrinsic value of options exercised	27,000	4,000	100,000
Total unrecognized compensation expense	19,500,000
Unrecognized compensation expense weighted-average period for recognition (In years)	2 years 8 months 23 days
2009 Option Exchange Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Life of stock options granted (years)	P6Y2M12D
Performance Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	9,240,165
Performance grants not probable, grant date fair value	12,200,000
Value of stock granted, share-based compensation reversed	1,600,000
Options cancelled (in shares)	2,107,732
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	4 years
Total unrecognized compensation expense	2,600,000
Unrecognized compensation expense weighted-average period for recognition (In years)	1 year 10 months 17 days
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount rate from market value on purchase date	85.00%
Discount rate from market value on offering date	85.00%
Stock-based compensation expense	$800,000	$600,000	$400,000
Number of shares available for grant	1,371,274
Common stock issued (shares)	669,565	345,828	298,533
Average price per share (in dollars per share)	$2.14	$4.13	$4.08

Employee_Benefit_Plans_Schedul

Employee Benefit Plans (Schedule Of Allocated Employee Stock-Based Compensation Expense) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	$10,006,000	$12,018,000	$8,781,000
Research and development expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	3,245,000	6,021,000	4,536,000
General and administrative expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	6,783,000	5,948,000	4,245,000
Restructuring-related stock compensation expense (recovery) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	($22,000)	$49,000	$0

Employee_Benefit_Plans_Schedul1

Employee Benefit Plans (Schedule Of Fair Value Of Employee Share-Based Payments Awards ESPP Assumptions And Weighted Average Fair Values) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value	$1.46	$2.97	$3.24
Risk-free interest rate	1.80%	1.51%	0.81%
Dividend yield	0.00%	0.00%	0.00%
Volatility	85.00%	61.00%	69.00%
Expected life	5 years 6 months	5 years 7 months 6 days	5 years 7 months 6 days
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value	$1.28	$1.64	$2.07
Risk-free interest rate	0.06%	0.11%	0.10%
Dividend yield	0.00%	0.00%	0.00%
Volatility	69.00%	66.00%	68.00%
Expected life	6 months	6 months	6 months

Employee_Benefit_Plans_Summary

Employee Benefit Plans (Summary Of All Stock Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of the year, Shares	23,983,275	18,448,550	17,436,378
Granted, Shares	10,038,565	6,694,174	3,442,696
Exercised, Shares	-19,090	-13,311	-181,979
Forfeited, Shares	-4,650,543	-79,942	-358,360
Expired, Shares	-1,540,215	-1,066,196	-1,890,185
Options outstanding at ending of the year, Shares	27,811,992	23,983,275	18,448,550
Exercisable at December 31, 2013	15,403,813
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options outstanding at beginning of the year, Weighted Average Exercise Price (dollars per share)	$6.48	$6.85	$7.16
Granted, Weighted Average Exercise Price (dollars per share)	$2.11	$5.44	$5.45
Exercised, Weighted Average Exercise Price (dollars per share)	$6.28	$5.06	$5.09
Forfeited, Weighted Average Exercise Price (dollars per share)	$5.34	$5.27	$5.88
Expired, Weighted Average Exercise Price (dollars per share)	$8.06	$6.45	$7.54
Options outstanding at ending of the year, Weighted Average Exercise Price (dollars per share)	$5	$6.48	$6.85
Exercisable at December 31, 2013, Weighted Average Exercise Price (dollars per share)	$6.75
Options outstanding, Weighted Average Remaining Contractual Term	4 years 2 months 15 days
Exercisable at December 31, 2013, Weighted Average Remaining Contractual Term	2 years 6 months 25 days
Options outstanding, Aggregate Intrinsic Value	$20
Exercisable at December 31, 2013, Aggregate Intrinsic Value	$0

Employee_Benefit_Plans_Summary1

Employee Benefit Plans (Summary Of Information About Stock Options Outstanding) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number (shares)	27,811,992
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 2 months 15 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$5
Options Outstanding and Exercisable, Number of Exercisable (shares)	15,403,813
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$6.75
$1.46 - $1.70 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$1.46
Exercise Price Range, upper (dollars per share)	$1.70
Options Outstanding, Number (shares)	8,430,075
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	6 years 7 months 20 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$1.70
Options Outstanding and Exercisable, Number of Exercisable (shares)	0
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)
$1.76 - $5.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$1.76
Exercise Price Range, upper (dollars per share)	$5.50
Options Outstanding, Number (shares)	4,880,183
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 7 months 17 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$4.78
Options Outstanding and Exercisable, Number of Exercisable (shares)	3,935,186
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$4.98
$5.51 - $5.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$5.51
Exercise Price Range, upper (dollars per share)	$5.60
Options Outstanding, Number (shares)	4,344,546
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 9 months 3 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$5.52
Options Outstanding and Exercisable, Number of Exercisable (shares)	1,628,954
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$5.53
$5.61 - $5.92 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$5.61
Exercise Price Range, upper (dollars per share)	$5.92
Options Outstanding, Number (shares)	3,397,550
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	1 year 11 months 26 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$5.69
Options Outstanding and Exercisable, Number of Exercisable (shares)	3,335,913
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$5.69
$5.94 - $8.90 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$5.94
Exercise Price Range, upper (dollars per share)	$8.90
Options Outstanding, Number (shares)	4,209,035
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 5 months 23 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$7.92
Options Outstanding and Exercisable, Number of Exercisable (shares)	3,953,157
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$7.96
$8.99 - $12.10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower (dollars per share)	$8.99
Exercise Price Range, upper (dollars per share)	$12.10
Options Outstanding, Number (shares)	2,550,603
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 1 month 27 days
Options Outstanding, Weighted Average Exercise Price (dollars per share)	$9.73
Options Outstanding and Exercisable, Number of Exercisable (shares)	2,550,603
Options Outstanding and Exercisable, Weighted Average Exercise Price (dollars per share)	$9.73

Employee_Benefit_Plans_Summary2

Employee Benefit Plans (Summary Of All RSU Activity) (Details) (Restricted Stock Units (RSUs) [Member], USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Awards outstanding at beginning of period, Shares	1,810,521	1,294,621	1,391,691
Awarded, Shares	559,659	1,119,733	733,958
Released, Shares	-459,939	-517,874	-596,397
Forfeited, Shares	-948,772	-85,959	-234,631
Awards outstanding at end of period, Shares	961,469	1,810,521	1,294,621
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Awards outstanding at beginning of period, Weighted Average Grant Date Fair Value (dollars per share)	$5.56	$6.07	$6.92
Awarded, Weighted Average Grant Date Fair Value (dollars per share)	$1.94	$5.45	$5.50
Released, Weighted Average Grant Date Fair Value (dollars per share)	$4.96	$6.60	$7.15
Forfeited, Weighted Average Grant Date Fair Value (dollars per share)	$5.48	$5.49	$6.62
Awards outstanding at end of period, Weighted Average Grant Date Fair Value (dollars per share)	$3.82	$5.56	$6.07
Awards outstanding, Weighted Average Remaining Contractual Term	1 year 10 months 17 days
Awards outstanding, Aggregate Intrinsic Value	$1,586

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Examination [Line Items]
Income tax (benefit) provision	($182,000)	($96,000)	$107,000
Prior year income taxes			100,000
Valuation allowance increased (decreased)	-89,700,000	-16,800,000	6,800,000
Tax benefit of stock option	16,000,000
Unrecognized tax benefit would affect the effective tax rate	100,000	100,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	20,000	15,000
Unrecognized Tax Benefits, Interest on Income Taxes Expense	4,000	6,000
Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards	1,213,000,000
Research and development tax credits	75,000,000
State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards	1,052,000,000
Maximum [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards, expiration dates	31-Dec-34
Maximum [Member] | Research And Development Expense [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards federal business credit expiration date	31-Dec-29
Maximum [Member] | State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards, expiration dates	31-Dec-34
Minimum [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards, expiration dates	31-Dec-20
Minimum [Member] | Research And Development Expense [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards federal business credit expiration date	31-Dec-20
Minimum [Member] | State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Operating loss carryforwards, expiration dates	31-Dec-15
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Research and development tax credits	$25,000,000

Income_Taxes_Schedule_Of_Conso

Income Taxes (Schedule Of Consolidated Net Income (Loss)) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic	($237,780)	($236,076)	($147,538)
Foreign	-30,944	-8,780	0
Loss before income taxes	($268,724)	($244,856)	($147,538)

Income_Taxes_Components_of_Inc

Income Taxes (Components of Income Tax Expense (Benefit)) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$0	$0	$32
State	-182	12	75
Total current tax expense	-182	12	107
Deferred:
Federal	0	-106	0
State	0	-2	0
Total deferred tax expense	0	-108	0
Income tax (benefit) provision	($182)	($96)	$107

Income_Taxes_Schedule_Of_Recon

Income Taxes (Schedule Of Reconciliation Of Income Taxes At The Statutory Federal Income Tax Rate To Net Income Taxes) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. federal income tax (benefit) provision at statutory rate	($91,366)	($83,251)	($50,163)
Unutilized net operating losses	87,448	-3,438	46,324
Non-deductible interest	3,598	3,380	3,297
Stock-based compensation	255	393	504
State tax expense	-182	10	74
Refundable tax credit	0	0	32
Available-for-sale investments	0	-106	0
Impact of intellectual property rights transfer	0	82,858	0
Other	65	58	39
Income tax (benefit) provision	($182)	($96)	$107

Income_Taxes_Schedule_Of_Defer

Income Taxes (Schedule Of Deferred Assets And Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Net operating loss carry-forwards	$446,343	$358,372
Tax credit and charitable contribution carry-forwards	64,368	64,635
Amortization of deferred stock compensation – non-qualified	27,500	24,279
Accruals and reserves not currently deductible	6,521	10,107
Deferred revenue	988	502
Book over tax depreciation and amortization	5,118	4,499
Total deferred tax assets	550,838	462,394
Valuation allowance	-511,171	-421,426
Net deferred tax assets	39,667	40,968
Deferred tax liabilities:
Unrealized gain on derivatives	-704	0
Convertible debt	-38,963	-40,968
Total deferred tax liabilities	-39,667	-40,968
Net deferred taxes	$0	$0

Income_Taxes_Schedule_Of_Unrec

Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$55,077	$47,298	$39,310
Increase (decrease) relating to prior year provision	719	-112	5,894
Increase relating to current year provision	2,706	7,891	2,094
Reductions based on the lapse of the applicable statutes of limitations	-287	0	0
Ending balance	$58,215	$55,077	$47,298

Net_Loss_Per_Share_Details

Net Loss Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net loss	($57,953)	($62,560)	($73,410)	($74,619)	($70,746)	($67,124)	($62,161)	($44,729)	($268,542)	($244,760)	($147,645)
Shares used in computing basic and diluted net loss per share									194,299	184,062	160,138
Net loss per share, basic and diluted (in dollars per share)	($0.30)	($0.32)	($0.38)	($0.39)	($0.38)	($0.36)	($0.34)	($0.24)	($1.38)	($1.33)	($0.92)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares									105,664	76,965	72,132
Convertible debt [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares									75,734	54,123	54,123
Outstanding stock options, unvested RSUs and ESPP contributions [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares									28,930	21,401	16,568
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares									1,000	1,441	1,441

Commitments_Schedule_Of_Aggreg

Commitments (Schedule Of Aggregate Future Minimum Lease Payments Under Operating Leases) (Details) (USD $)	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
2015	$20,152,000	[1]
2016	16,431,000	[1]
2017	9,104,000	[1]
2018	2,806,000	[1]
Thereafter	0	[1]
Total	48,493,000	[1]
Future minimum rental under noncancelable subleases	$9,200,000
[1]	Minimum payments have not been reduced by minimum sublease rentals of $9.2 million due in the future under noncancelable subleases.

Commitments_Schedule_Of_Aggreg1

Commitments (Schedule Of Aggregate Future Minimum Lease Payments Under Operating Leases By Material Lease Agreements) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
	renewal
Operating Leased Assets [Line Items]
Future Minimum Lease Payment	$48,493
Building Lease #1&2 [Member]
Operating Leased Assets [Line Items]
Original Term (Expiration)	1-May-17
Number of Renewal Options	2
Period of Renewal Option, in years	5 years
Future Minimum Lease Payment	27,556
Building Lease #3 [Member]
Operating Leased Assets [Line Items]
Original Term (Expiration)	1-Jul-18
Number of Renewal Options	1
Period of Renewal Option, in years	5 years
Future Minimum Lease Payment	16,660
Building Lease #4 [Member]
Operating Leased Assets [Line Items]
Original Term (Expiration)	1-Dec-15
Number of Renewal Options	1
Period of Renewal Option, in years	3 years
Future Minimum Lease Payment	4,211
Other [Member]
Operating Leased Assets [Line Items]
Future Minimum Lease Payment	$66

Commitments_Narrative_Details

Commitments (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]
Rent expenses under operating leases	$10,300,000	$9,100,000	$17,800,000
Net of sublease rentals under operating leases	4,900,000	4,100,000	3,800,000
Collateral provided for purchasing card program	3,500,000	3,500,000
Building Lease [Member]
Operating Leased Assets [Line Items]
Standby letter of credit, amount	500,000	500,000
Workers Compensation Insurance Policy [Member]
Operating Leased Assets [Line Items]
Standby letter of credit, amount	$700,000	$700,000

Concentrations_of_Credit_Risk_1

Concentrations of Credit Risk (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Concentration Risk [Line Items]
Foreign exchange fluctuations gain (loss)	0.5
Diplomat Specialty Pharmacy [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	92.00%
Diplomat Specialty Pharmacy [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	99.00%	45.00%	0.00%
Bristol-Myers Squibb [Member] | Revenue, Rights Granted [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	52.00%	66.00%
Merck [Member] | Revenue, Rights Granted [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	0.00%	22.00%
Daiichi Sankyo [Member] | Revenue, Rights Granted [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	0.00%	12.00%
Sobi [Member]
Concentration Risk [Line Items]
Reduction to net product revenues	2.3
United States [Member] | Sales [Member] | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	99.00%	97.00%	100.00%
European Union [Member] | Sales [Member] | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	1.00%	3.00%	0.00%

Quarterly_Financial_Data_Unaud2

Quarterly Financial Data (Unaudited) (Schedule Of Quarterly Financial Data) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenues	$7,353	$6,291	$6,562	$4,905	$4,347	$5,466	$11,856	$9,669
Gross profit	6,669	5,718	6,085	4,596	4,084	5,176	11,571	9,389
Loss from operations	-46,208	-51,574	-61,688	-64,988	-59,514	-55,913	-51,295	-34,010
Net loss	($57,953)	($62,560)	($73,410)	($74,619)	($70,746)	($67,124)	($62,161)	($44,729)	($268,542)	($244,760)	($147,645)
Net loss per share, basic and diluted (in dollars per share)	($0.30)	($0.32)	($0.38)	($0.39)	($0.38)	($0.36)	($0.34)	($0.24)	($1.38)	($1.33)	($0.92)