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Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2013	Oct. 25, 2013
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 27, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Trading Symbol	exel
Entity Registrant Name	EXELIXIS, INC.
Entity Central Index Key	0000939767
Entity Filer Category	Large Accelerated Filer
Current Fiscal Year End Date	--12-27
Entity Common Stock, Shares Outstanding		184,204,393

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 92,016	$ 170,069
Short-term Investments	187,203	241,371
Short-term restricted cash and investments	12,211	12,246
Trade and other receivables	5,171	2,751
Inventory	1,764	0
Prepaid expenses and other current assets	7,799	6,104
Total current assets	306,164	432,541
Long-term investments	157,402	182,311
Long-term restricted cash and investments	15,889	27,964
Property and equipment, net	5,520	6,059
Goodwill	63,684	63,684
Other assets	7,300	8,538
Total assets	555,959	721,097
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	3,559	4,398
Accrued clinical trial liabilities	35,042	20,560
Accrued compensation and benefits	9,342	10,375
Other accrued liabilities	13,017	11,795
Current portion of convertible notes	10,000	10,000
Current portion of loans payable	2,127	3,170
Current portion of restructuring	3,776	5,085
Deferred revenue	1,017	16,321
Total current liabilities	77,880	81,704
Long-term portion of convertible notes	248,707	240,476
Long-term portion of loans payable	80,757	82,090
Long-term portion of restructuring	10,126	14,137
Other long-term liabilities	5,726	6,256
Total liabilities	423,196	424,663
Contingencies (Note 10)
Stockholders' Equity:
Preferred stock	0	0
Common stock, $0.001 par value; 400,000,000 shares authorized; issued and outstanding: 184,194,124 and 183,697,213 shares at September 30, 2013 and December 31, 2012, respectively	184	183
Additional paid-in capital	1,560,415	1,550,345
Accumulated other comprehensive income (loss)	180	(92)
Accumulated deficit	(1,428,016)	(1,254,002)
Total stockholders’ equity	132,763	296,434
Total liabilities and stockholders' equity	$ 555,959	$ 721,097

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Common stock, par value, in dollars per share	$ 0.001	$ 0.001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	184,194,124	183,697,213
Common stock, shares outstanding	184,194,124	183,697,213

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:
License and contract revenues	$ 695	$ 13,313	$ 16,321	$ 39,636
Net product revenues	4,771	0	10,670	0
Total revenues	5,466	13,313	26,991	39,636
Operating expenses:
Cost of goods sold	290	0	855	0
Research and development	47,354	30,680	129,166	96,386
Selling, general and administrative	13,598	7,343	37,323	22,008
Restructuring charge	137	733	865	1,704
Total operating expenses	61,379	38,756	168,209	120,098
Loss from operations	(55,913)	(25,443)	(141,218)	(80,462)
Other income (expense), net:
Interest income and other, net	219	318	930	818
Interest expense	(11,430)	(7,679)	(33,726)	(15,775)
Total other income (expense), net	(11,211)	(7,361)	(32,796)	(14,957)
Loss before income taxes	(67,124)	(32,804)	(174,014)	(95,419)
Income tax provision	0	10	0	33
Net loss	$ (67,124)	$ (32,814)	$ (174,014)	$ (95,452)
Net loss per share, basic and diluted, in dollars per share	$ (0.36)	$ (0.20)	$ (0.95)	$ (0.63)
Shares used in computing basic and diluted net loss per share, in shares	184,149	166,354	183,957	152,316

Consolidated Statements of Comprehensive Loss - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Statement of Comprehensive Income [Abstract]

Net loss

$ (67,124)

$ (32,814)

$ (174,014)

$ (95,452)

Other comprehensive income (loss)

^[1]

443

(23)

272

120

Comprehensive loss

$ (66,681)

$ (32,837)

$ (173,742)

$ (95,332)

[1]

Other comprehensive income (loss) consisted solely of unrealized gains or losses on available for sale securities arising during the periods presented. There were no reclassification adjustments to net income resulting from realized gains or losses on the sale of securities and there was no income tax expense related to other comprehensive income during those periods.

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

+ Details

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (174,014)	$ (95,452)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,382	4,071
Stock-based compensation expense	8,503	6,222
Restructuring credit for property and equipment	0	(141)
Accretion of debt discount	19,445	8,624
Other	5,243	3,450
Changes in assets and liabilities:
Other receivables	(2,420)	27,082
Inventory	(1,764)	0
Prepaid expenses and other current assets	(1,495)	(1,892)
Other assets	0	(1,983)
Accounts payable and other accrued liabilities	(652)	1,308
Clinical trial liability	14,482	1,972
Restructuring liability	(5,320)	(3,489)
Other long-term liabilities	(530)	(76)
Deferred revenue	(15,304)	(34,106)
Net cash used in operating activities	(151,444)	(84,410)
Cash flows from investing activities:
Purchases of property and equipment	(2,079)	(1,528)
Proceeds from sale of property and equipment	40	877
Proceeds from maturities of restricted cash and investments	15,968	4,199
Purchase of restricted cash and investments	(3,785)	(40,188)
Proceeds from maturities of investments	251,470	236,323
Purchases of investments	(176,768)	(359,524)
Net cash provided by (used in) investing activities	84,846	(159,841)
Cash flows from financing activities:
Proceeds from issuance of common stock, net	0	203,479
Proceeds from exercise of stock options and warrants	25	901
Proceeds from employee stock purchase plan	894	828
Proceeds from debt issuance, net	0	277,673
Principal payments on debt	(12,374)	(4,082)
Net cash (used in) provided by financing activities	(11,455)	478,799
Net (decrease) increase in cash and cash equivalents	(78,053)	234,548
Cash and cash equivalents at beginning of period	170,069	74,257
Cash and cash equivalents at end of period	$ 92,016	$ 308,805

Organization and Summary of Significant Accounting Policies	45 Months Ended
	Sep. 30, 2013
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 biotechnology company committed to developing small molecule therapies for the treatment of cancer. We are focusing our proprietary resources and development and commercialization efforts exclusively on COMETRIQ^® (cabozantinib), our wholly-owned inhibitor of multiple receptor tyrosine kinases. On November 29, 2012, the U.S. Food and Drug Administration approved COMETRIQ for the treatment of progressive, metastatic medullary thyroid cancer (“MTC”), in the United States, where it became commercially available in late January 2013. Cabozantinib is being evaluated in a variety of other cancer indications through a broad development program, including two ongoing phase 3 pivotal trials in metastatic castration-resistant prostate cancer, an ongoing phase 3 pivotal trial in metastatic renal cell cancer and an ongoing phase 3 pivotal trial in advanced hepatocellular cancer. We believe COMETRIQ has the potential to be a high-quality, broadly-active and differentiated anti-cancer agent that can make a meaningful difference in the lives of patients. Our objective is to develop COMETRIQ into a major oncology franchise, and we believe that the approval of COMETRIQ for the treatment of progressive, metastatic MTC provides us with the opportunity to establish a commercial presence in furtherance of this objective. We have also established a portfolio of other novel compounds that we believe have the potential to address serious unmet medical needs. Many of these compounds are being developed by partners as part of collaborations, at no cost to us but with significant retained economics to us in the event these compounds are commercialized. As disclosed on ClinicalTrials.gov (NCT01689519), a phase 3 clinical trial for one of these compounds, cobimetinib (GDC-0973/XL518), which we out-licensed to Genentech, Inc. (a wholly-owned member of the Roche Group), was initiated on November 1, 2012. 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”). In September 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. All intercompany balances and transactions have been eliminated. Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. In our opinion, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation of the results of operations and cash flows for the period presented have been included. Exelixis adopted a 52- or 53-week fiscal year that generally ends on the Friday closest to December 31^st. Fiscal year 2012, a 52-week year, ended on December 28, 2012, and fiscal year 2013, a 52-week year, will end on December 27, 2013. For convenience, references in this report as of and for the fiscal quarters ended September 28, 2012 and September 27, 2013, and as of the fiscal year ended December 28, 2012, are indicated as ended September 30, 2012, September 30, 2013, and December 31, 2012, respectively. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2013 or for any future period. These financial statements and notes should be read in conjunction with the consolidated financial statements and notes thereto for the fiscal year ended December 31, 2012, included in our Annual Report on Form 10-K filed with the SEC on February 21, 2013. Segment Information We operate in one business segment. Use of Estimates The preparation of the consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make 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 inventory, revenue recognition, cost of goods sold, valuation of long-lived assets, certain accrued liabilities including clinical trial accruals and restructuring liability, share-based compensation and the valuation of the debt and equity components of our convertible debt at issuance. We base our estimates on historical experience and on various other market-specific and other relevant assumptions that are believed 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. Inventory 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 are not capitalized as inventory but rather are expensed as research and development costs. When regulatory approval is obtained, we begin capitalization of inventory related costs. We received regulatory approval for our first product, COMETRIQ, on November 29, 2012. 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 that has become obsolete, or has a cost basis in excess of its expected net realizable value and inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Consolidated Statements of Operations. 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, which is consistent with our sole operating segment as of September 30, 2013 and December 31, 2012. Revenue Recognition We recognize revenue from the sale of COMETRIQ and from license fees and milestones earned on research and collaboration arrangements. See “Note 1 - Organization and Summary of Significant Accounting Policies” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012 for a description of our policies for revenue recognition on research and collaboration agreements. We did not enter into any new collaboration agreements during the nine months ended September 30, 2013. See “Note 2 - Research and Collaboration Agreements” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012 for a description of our existing collaboration agreements. 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. 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 payors 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 payor 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 customer incentives, 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 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. These discounts and allowances apply only to gross product revenues earned in the United States. 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 payor data received from the United States specialty pharmacy. Rebates are generally invoiced by the payor 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 payor 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. 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 a 3% royalty we are required to pay GlaxoSmithKline and indirect labor costs. A significant portion of the manufacturing costs for current 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 incurred, rather than capitalized as inventory. In accordance with our 2002 collaboration 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 collaboration 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. Recently Adopted Accounting Pronouncements In February 2013, Accounting Standards Codification Topic 220, Comprehensive Income was amended to require additional information about amounts reclassified out of accumulated other comprehensive income. We adopted this guidance beginning January 1, 2013, and will provide the additional information when such reclassifications occur. The amendment did not have a material effect on our consolidated financial statements.

Restructurings

9 Months Ended

Sep. 30, 2013

Restructuring Charges [Abstract]

Restructurings

RESTRUCTURINGS

Between March 2010 and May 2013, we implemented five restructurings (referred to collectively as the “Restructurings”) as a consequence of our decision to focus our proprietary resources and development efforts on the development and commercialization of cabozantinib and strategy to manage costs. The aggregate reduction in headcount from the Restructurings was 429 employees. Charges and credits related to the Restructurings were recorded in periods other than those in which the 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.

We have recorded aggregate restructuring charges of $52.9 million in connection with the Restructurings, of which $28.9 million related to facility charges, $21.7 million related to termination benefits, $2.2 million related to the impairment of excess equipment and other assets, and an additional minor amount related to legal and other fees. Asset impairment charges, net were partially offset by cash proceeds of $2.6 million from the sale of such assets.

For the nine months ended September 30, 2013 and 2012, we recorded restructuring charges of $0.9 million and $1.7 million, respectively, which related primarily to termination benefits and facility charges in connection with the exit of portions of certain of our buildings in South San Francisco. Those charges were partially offset by a $0.7 million credit resulting from a new sublease entered into during the three months ended September 30, 2013.

The total outstanding restructuring liability related to the Restructurings is included in current and long-term portion of restructuring on our Consolidated Balance Sheets. The components and changes of these liabilities during the annual periods from inception of the restructuring activities through the year ended December 31, 2012 and during the nine months ended September 30, 2013 are summarized in the following table (in thousands):



	Employee Severance and Other Benefits			Facility Charges			Asset Impairment			Legal and Other Fees			Total
Restructuring liability as of December 31, 2011	$	6		$	13,921		$	—		$	51		$	13,978
Restructuring charge (credit)	970			8,276			(47		)	(28		)	9,171
Cash payments	(965		)	(5,299		)	—			(3		)	(6,267		)
Adjustments or non-cash credits including stock compensation expense	(11		)	2,304			(891		)	—			1,402
Proceeds from sale of assets	—			—			938			—			938
Restructuring liability as of December 31, 2012	—			19,202			—			20			19,222
Restructuring charge (credit)	496			359			25			(15		)	865
Cash payments	(424		)	(5,608		)	—			—			(6,032		)
Adjustments or non-cash credits including stock compensation expense	(55		)	(73		)	(25		)	—			(153		)
Restructuring liability as of September 30, 2013	$	17		$	13,880		$	—		$	5		$	13,902

We expect to pay accrued facility charges of $13.9 million, net of cash received from our subtenants, through 2017, or the end of our lease terms of the buildings. With respect to our Restructurings, we expect to incur additional restructuring charges of approximately $1.8 million which relate to the exit, in prior periods, of certain of our South San Francisco buildings. These charges will be recorded through the end of the building lease terms, the last of which ends in 2017.

The Restructurings have resulted in aggregate cash expenditures of $34.8 million, net of $9.1 million in cash received from subtenants and $2.6 million in cash received in connection with the sale of excess equipment and other assets. Net cash expenditures for the Restructurings were $2.1 million and $2.2 million during the three months ended September 30, 2013, and 2012, respectively and $6.0 million and $4.5 million during the nine months ended September 30, 2013 and 2012, respectively.

The restructuring charges that we expect to incur in connection with the 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.

Cash and Investments

9 Months Ended

Sep. 30, 2013

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 September 30, 2013 and December 31, 2012 (in thousands):



	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
As reported:
Cash and cash equivalents	$	92,016	$	—	$	—		$	92,016
Short-term investments	187,086		141		(24		)	187,203
Short-term restricted cash and investments	12,172		39		—			12,211
Long-term investments	157,437		63		(98		)	157,402
Long-term restricted cash and investments	15,830		59		—			15,889
Total cash and investments	$	464,541	$	302	$	(122	)	$	464,721



	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
As reported:
Cash and cash equivalents	$	170,070	$	—	$	(1	)	$	170,069
Short-term investments	241,391		46		(66		)	241,371
Short-term restricted cash and investments	12,242		4		—			12,246
Long-term investments	182,407		28		(124		)	182,311
Long-term restricted cash and investments	27,943		21		—			27,964
Total cash and investments	$	634,053	$	99	$	(191	)	$	633,961

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 and certain other designated financial institutions. The total collateral balances as of September 30, 2013 and December 31, 2012 were $84.5 million and $87.0 million, respectively, and are reflected in our Consolidated Balance Sheets in short- and long-term investments. See “Note 7 - Debt” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012, 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 and cash equivalents and investments by security type as of September 30, 2013 and December 31, 2012 (in thousands):



	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and money market funds	$	62,645	$	—	$	—		$	62,645
Commercial paper	43,591		1		—			43,592
Corporate bonds	266,700		173		(122		)	266,751
U.S. Treasury and government sponsored enterprises	83,323		119		—			83,442
Municipal bonds	8,282		9		—			8,291
Total cash and investments	$	464,541	$	302	$	(122	)	$	464,721



	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and money market funds	$	81,744	$	2	$	—		$	81,746
Commercial paper	167,223		8		—			167,231
Corporate bonds	222,106		30		(187		)	221,949
U.S. Treasury and government sponsored enterprises	132,933		59		(1		)	132,991
Municipal bonds	30,047		—		(3		)	30,044
Total cash and investments	$	634,053	$	99	$	(191	)	$	633,961

All of our investments are subject to a quarterly impairment review. During the three and nine months ended September 30, 2013 and 2012, we did not record any other-than-temporary impairment charges on our available-for-sale securities. As of September 30, 2013, the fair value of investments that were in an unrealized loss position was $106.8 million, including $105.8 million in corporate bonds. There were 53 investments in an unrealized loss position as of September 30, 2013. 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 September 30, 2013 (in thousands):



	Mature within One Year		After One Year through Two Years		Fair Value
Money market funds	$	58,102	$	—	$	58,102
Commercial paper	43,592		—		43,592
Corporate bonds	168,715		98,036		266,751
U.S. Treasury and government sponsored enterprises	71,279		12,163		83,442
Municipal bonds	2,212		6,079		8,291
Total	$	343,900	$	116,278	$	460,178

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.

During the three and nine months ended September 30, 2013 and 2012, there were no sales of investments, and therefore there were no reclassification adjustments of accumulated other comprehensive income to net income resulting from realized gains or losses on the sale of securities.

Inventory

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Inventory

INVENTORY

Inventory consists of the following (in thousands):



	September 30, 2013		December 31, 2012
Raw materials	$	301	$	—
Work in process	1,374		—
Finished goods	89		—
Total	$	1,764	$	—

We received regulatory approval for our first product, COMETRIQ, on November 29, 2012. As of December 31, 2012, our recorded inventory balance was $0 as we did not incur any costs that would be recorded as inventory subsequent to the receipt of regulatory approval and prior to year end.

Debt

9 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Debt

DEBT

The amortized carrying amount of our debt consists of the following (in thousands):



	September 30, 2013			December 31, 2012
Convertible Senior Subordinated Notes due 2019	$	161,279		$	149,800
Secured Convertible Notes due 2015	97,428			100,676
Silicon Valley Bank term loan	80,000			80,000
Silicon Valley Bank line of credit	2,884			5,260
Total debt	341,591			335,736
Less: current portion	(12,127		)	(13,170		)
Long-term debt	$	329,464		$	322,566

See “Note 7 - Debt” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012, for additional information on the terms of our debt, including a description of the conversion features of the of 4.25% Convertible Senior Subordinated Notes due 2019 (the “2019 Notes”) and our Secured Convertible Notes due June 2015 (the “Deerfield Notes”).

Convertible Senior Subordinated Notes due 2019

In August 2012, we issued and sold $287.5 million aggregate principal amount the 2019 Notes. As of September 30, 2013, the entire principal balance remains outstanding. The following is a summary of the liability component of the 2019 Notes as of September 30, 2013 (in thousands):



	September 30, 2013
Net carrying amount of the liability component	$	161,279
Unamortized discount of the liability component	126,221
Face amount of the 2019 Notes	$	287,500

The debt discount and debt issuance costs will be amortized as interest expense through August 2019. During the three and nine months ended September 30, 2013, total interest expense for the 2019 Notes was $7.2 million, and $21.2 million, respectively, including stated coupon interest of $3.1 million and $9.2 million, respectively, and the amortization of the debt discount and debt issuance costs of $4.1 million and $12.0 million, respectively. During both the three and nine months ended September 30, 2012, total interest expense for the 2019 Notes was $3.4 million including stated coupon interest of $1.5 million and the amortization of the debt discount and debt issuance costs of $1.9 million. The balance of unamortized fees and costs was $4.1 million and $4.7 million as of September 30, 2013 and December 31, 2012, respectively, which is recorded in the accompanying Consolidated Balance Sheet as Other assets.

Secured Convertible Notes due June 2015

In June 2010, we entered into a note purchase agreement with entities affiliated with Deerfield Management Company, L.P. (“Deerfield”), pursuant to which, on July 1, 2010, we sold to Deerfield an aggregate of $124.0 million initial principal amount of the Deerfield Notes. As of September 30, 2013 and December 31, 2012, the remaining outstanding principal balance on the Deerfield Notes was $114.0 million and $124.0 million, respectively. During the three and nine months ended September 30, 2013, total interest expense for the Deerfield Notes was $4.1 million and $11.9 million, respectively, and during the same periods in 2012, $4.1 million and $11.7 million, respectively, including the stated coupon rate and the amortization of the debt discount and debt issuance costs. The non-cash expense relating to the amortization of the debt discount and debt issuance costs were $2.6 million and $7.4 million during the three and nine months ended September 30, 2013, respectively, and $2.5 million and $7.2 million, during the three and nine months ended September 30, 2012, respectively. The balance of unamortized fees and costs was $1.6 million and $2.3 million as of September 30, 2013 and December 31, 2012, respectively, which is recorded in the accompanying Consolidated Balance Sheet as Other assets.

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 parties amended the security agreement to limit the extent to which voting equity interests in any of our foreign subsidiaries shall be secured assets.

Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

The fair value of our financial instruments 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). The fair value hierarchy has the following three levels:

Level 1 – quoted prices in active markets for identical assets and liabilities.

Level 2 – observable inputs other than quoted prices in active markets for identical assets and liabilities. 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. There were no transfers between any of the fair value hierarchies, as determined at the end of each reporting period.

The following table sets forth the fair value of our financial assets that were measured and recorded on a recurring basis as of September 30, 2013 and December 31, 2012. We did not have any Level 3 investments during the periods presented. The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):



	September 30, 2013
	Level 1		Level 2		Total
Money market funds	$	58,102	$	—	$	58,102
Commercial paper	—		43,592		43,592
Corporate bonds	—		266,751		266,751
U.S. Treasury and government sponsored enterprises	—		83,442		83,442
Municipal bonds	—		8,291		8,291
Total	$	58,102	$	402,076	$	460,178



	December 31, 2012
	Level 1		Level 2		Total
Money market funds	$	76,050	$	—	$	76,050
Commercial paper	—		167,231		167,231
Corporate bonds	—		221,949		221,949
U.S. Treasury and government sponsored enterprises	—		132,991		132,991
Municipal bonds	—		30,044		30,044
Total	$	76,050	$	552,215	$	628,265

The estimated fair values of our financial instruments that are carried at amortized cost for which it is practicable to determine a fair value were as follows (in thousands):



	September 30, 2013				December 31, 2012
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
2019 Notes	$	161,279	$	337,928	$	149,800	$	280,111
Silicon Valley Bank term loan	$	80,000	$	79,884	$	80,000	$	79,542
Silicon Valley Bank Line of Credit	$	2,884	$	2,884	$	5,260	$	5,253

There is no practicable method 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 and the current non-liquid market in structured notes. The carrying amounts of cash, trade and other receivables, accounts payable and accrued clinical trial 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’ equity in the accompanying Consolidated Balance Sheets.


•	We have estimated 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.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stock-Based Compensation

9 Months Ended

Sep. 30, 2013

Share-based Compensation [Abstract]

Stock-Based Compensation

STOCK-BASED COMPENSATION

We recorded and allocated employee stock-based compensation expenses for our equity incentive plans and our 2000 Employee Stock Purchase Plan (“ESPP”) as follows (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Research and development expense	$	1,415	$	970	$	4,326	$	3,202
Selling, general and administrative expense	1,478		923		4,115		2,970
Restructuring-related stock-based compensation expense	—		—		49		—
Total employee stock-based compensation expense	$	2,893	$	1,893	$	8,490	$	6,172

We use the Black-Scholes 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
	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Weighted average grant-date fair value	$	2.99		$	3.31		$	2.92		$	3.27
Risk-free interest rate	1.57		%	0.81		%	1.47		%	0.82		%
Dividend yield	—		%	—		%	—		%	—		%
Volatility	60		%	69		%	60		%	69		%
Expected life	5.6 years			5.6 years			5.6 years			5.7 years



	Employee Stock Purchase Plan
	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Weighted average grant-date fair value	$	1.74		$	1.63		$	1.66		$	2.13
Risk-free interest rate	0.08		%	0.15		%	0.12		%	0.10		%
Dividend yield	—		%	—		%	—		%	—		%
Volatility	67		%	68		%	67		%	68		%
Expected life	0.5 years			0.5 years			0.5 years			0.5 years

Of the stock options outstanding as of September 30, 2013, 3,720,752 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 September 30, 2013, we expect that achievement of some of those performance objectives is probable and have, therefore, included stock-based compensation for such awards. We have not included any stock-based compensation expense for stock options with performance objectives where the performance goals cannot be reasonably assured of achievement.

A summary of all stock option activity for the nine months ended September 30, 2013 is presented below (dollars in thousands, except per share amounts):



	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Options outstanding at December 31, 2012	18,448,550		$	6.85
Granted	5,778,323		$	5.38
Exercised	(4,473	)	$	4.42
Forfeited	(712,885	)	$	6.42
Options outstanding at September 30, 2013	23,509,515		$	6.50	4.71	$	5,709
Exercisable at September 30, 2013	13,803,103		$	7.23	3.51	$	2,376

As of September 30, 2013, $24.4 million of total unrecognized compensation expense related to employee stock options was expected to be recognized over a weighted-average period of 2.92 years.

A summary of all restricted stock unit (“RSU”) activity for the nine months ended September 30, 2013 is presented below (dollars in thousands, except per share amounts):



	Shares		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Awards outstanding at December 31, 2012	1,294,621		$	6.07
Awarded	1,058,668		$	5.44
Released	(230,059	)	$	7.34
Forfeited	(72,132	)	$	5.48
Awards outstanding at September 30, 2013	2,051,098		$	5.62	1.98	$	11,855

As of September 30, 2013, $8.0 million of total unrecognized compensation expense related to employee RSUs was expected to be recognized over a weighted-average period of 3.33 years.

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES At December 31, 2012, we had federal net operating loss carry-forwards of approximately $1,007 million which expire in the years 2018 through 2032. We also had net operating loss carry-forwards for California of approximately $880 million, which expire in the years 2013 through 2032, and California tax credits of approximately $26 million. During the three months ended September 30, 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.

Net Loss Per Share

9 Months Ended

Sep. 30, 2013

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):



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Numerator:
Net loss	$	(67,124	)	$	(32,814	)	$	(174,014	)	$	(95,452	)
Denominator:
Shares used in computing basic and diluted net loss per share	184,149			166,354			183,957			152,316
Net loss per share, basic and diluted	$	(0.36	)	$	(0.20	)	$	(0.95	)	$	(0.63	)

The following table sets forth outstanding potential shares of common stock that are not included in the computation of diluted net loss per share because, to do so would be anti-dilutive (in thousands):



	September 30
	2013	2012
Convertible debt	54,123	54,123
Outstanding stock options, unvested RSUs and ESPP contributions	25,694	15,839
Warrants	1,441	1,441
Total potentially dilutive shares	81,258	71,403

Contingencies	9 Months Ended
Contingencies	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIES Pending Litigation From time to time, we are party to legal proceedings, claims and investigations in the ordinary course of business, including the matter described below. In December 2012, a former officer filed a lawsuit against us and our chief executive officer in California state court seeking unspecified monetary damages based on contract and tort claims in connection with the former officer’s execution and revocation of a Rule 10b5-1 stock trading plan in December 2010. This matter was settled for an immaterial amount during the three months ended September 30, 2013.

Concentrations of Credit Risk

9 Months Ended

Sep. 30, 2013

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. government agency obligations and U.S. government sponsored enterprises. 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 September 30, 2013, 55% of our trade receivables are with the specialty pharmacy that sells COMETRIQ in the United States and 14% are with our European distribution partner. Both of these customers pay promptly and within their respective payment terms.

We have operations primarily in the United States, while some of our collaboration partners have headquarters outside of the United States and certain of our clinical trials for cabozantinib are conducted outside of the United States. During the three and nine months ended September 30, 2012, 100% of our revenues were earned in the United States. During the 2013, we initiated a Named Patient Use (“NPU”) program through our distribution partner, Swedish Orphan Biovitrum, to support the distribution and commercialization of COMETRIQ for metastatic MTC primarily in the European Union and potentially other countries. During the three and nine months ended September 30, 2013, 87% and 96%, respectively, of our revenues were earned in the United States; the remainder of our revenues were earned in the European Union under this NPU program. All of our long-lived assets are located in the United States.

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 during the nine months ended September 30, 2013 and 2012:



	Nine Months Ended September 30,
	2013		2012
Collaborator:
Bristol-Myers Squibb	60	%	59	%
Merck	—	%	27	%
Daiichi Sankyo	—	%	14	%
Pharmacy:
Diplomat Specialty Pharmacy	36	%	—	%

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Exelixis, Inc. (“Exelixis,” “we,” “our” or “us”) is a biotechnology company committed to developing small molecule therapies for the treatment of cancer. We are focusing our proprietary resources and development and commercialization efforts exclusively on COMETRIQ^® (cabozantinib), our wholly-owned inhibitor of multiple receptor tyrosine kinases. On November 29, 2012, the U.S. Food and Drug Administration approved COMETRIQ for the treatment of progressive, metastatic medullary thyroid cancer (“MTC”), in the United States, where it became commercially available in late January 2013. Cabozantinib is being evaluated in a variety of other cancer indications through a broad development program, including two ongoing phase 3 pivotal trials in metastatic castration-resistant prostate cancer, an ongoing phase 3 pivotal trial in metastatic renal cell cancer and an ongoing phase 3 pivotal trial in advanced hepatocellular cancer. We believe COMETRIQ has the potential to be a high-quality, broadly-active and differentiated anti-cancer agent that can make a meaningful difference in the lives of patients. Our objective is to develop COMETRIQ into a major oncology franchise, and we believe that the approval of COMETRIQ for the treatment of progressive, metastatic MTC provides us with the opportunity to establish a commercial presence in furtherance of this objective. We have also established a portfolio of other novel compounds that we believe have the potential to address serious unmet medical needs. Many of these compounds are being developed by partners as part of collaborations, at no cost to us but with significant retained economics to us in the event these compounds are commercialized. As disclosed on ClinicalTrials.gov (NCT01689519), a phase 3 clinical trial for one of these compounds, cobimetinib (GDC-0973/XL518), which we out-licensed to Genentech, Inc. (a wholly-owned member of the Roche Group), was initiated on November 1, 2012.
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”). In September 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. All intercompany balances and transactions have been eliminated.
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. In our opinion, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation of the results of operations and cash flows for the period presented have been included. Exelixis adopted a 52- or 53-week fiscal year that generally ends on the Friday closest to December 31^st. Fiscal year 2012, a 52-week year, ended on December 28, 2012, and fiscal year 2013, a 52-week year, will end on December 27, 2013. For convenience, references in this report as of and for the fiscal quarters ended September 28, 2012 and September 27, 2013, and as of the fiscal year ended December 28, 2012, are indicated as ended September 30, 2012, September 30, 2013, and December 31, 2012, respectively. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2013 or for any future period. These financial statements and notes should be read in conjunction with the consolidated financial statements and notes thereto for the fiscal year ended December 31, 2012, included in our Annual Report on Form 10-K filed with the SEC on February 21, 2013.
Fiscal Period, Policy	Exelixis adopted a 52- or 53-week fiscal year that generally ends on the Friday closest to December 31^st.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements is in conformity with accounting principles generally accepted in the United States which requires management to make 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 inventory, revenue recognition, cost of goods sold, valuation of long-lived assets, certain accrued liabilities including clinical trial accruals and restructuring liability, share-based compensation and the valuation of the debt and equity components of our convertible debt at issuance. We base our estimates on historical experience and on various other market-specific and other relevant assumptions that are believed 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.
Inventory	Inventory 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 are not capitalized as inventory but rather are expensed as research and development costs. When regulatory approval is obtained, we begin capitalization of inventory related costs. We received regulatory approval for our first product, COMETRIQ, on November 29, 2012. 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 that has become obsolete, or has a cost basis in excess of its expected net realizable value and inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Consolidated Statements of Operations.
Goodwill and Intangible Assets, Policy [Policy Text Block]	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, which is consistent with our sole operating segment as of September 30, 2013 and December 31, 2012.
Revenue Recognition	Revenue Recognition We recognize revenue from the sale of COMETRIQ and from license fees and milestones earned on research and collaboration arrangements. See “Note 1 - Organization and Summary of Significant Accounting Policies” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012 for a description of our policies for revenue recognition on research and collaboration agreements. We did not enter into any new collaboration agreements during the nine months ended September 30, 2013. See “Note 2 - Research and Collaboration Agreements” to our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2012 for a description of our existing collaboration agreements. 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. 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 payors 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 payor 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 customer incentives, 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 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. These discounts and allowances apply only to gross product revenues earned in the United States. 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 payor data received from the United States specialty pharmacy. Rebates are generally invoiced by the payor 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 payor 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. 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 a 3% royalty we are required to pay GlaxoSmithKline and indirect labor costs. A significant portion of the manufacturing costs for current 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 incurred, rather than capitalized as inventory. In accordance with our 2002 collaboration 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 collaboration 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.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In February 2013, Accounting Standards Codification Topic 220, Comprehensive Income was amended to require additional information about amounts reclassified out of accumulated other comprehensive income. We adopted this guidance beginning January 1, 2013, and will provide the additional information when such reclassifications occur. The amendment did not have a material effect on our consolidated financial statements.
Segment Reporting, Policy [Policy Text Block]	Segment Information We operate in one business segment.

Restructurings (Tables)

9 Months Ended

Sep. 30, 2013

Restructuring Charges [Abstract]

Summary Of Components Of Restructuring Liability

The components and changes of these liabilities during the annual periods from inception of the restructuring activities through the year ended December 31, 2012 and during the nine months ended September 30, 2013 are summarized in the following table (in thousands):



	Employee Severance and Other Benefits			Facility Charges			Asset Impairment			Legal and Other Fees			Total
Restructuring liability as of December 31, 2011	$	6		$	13,921		$	—		$	51		$	13,978
Restructuring charge (credit)	970			8,276			(47		)	(28		)	9,171
Cash payments	(965		)	(5,299		)	—			(3		)	(6,267		)
Adjustments or non-cash credits including stock compensation expense	(11		)	2,304			(891		)	—			1,402
Proceeds from sale of assets	—			—			938			—			938
Restructuring liability as of December 31, 2012	—			19,202			—			20			19,222
Restructuring charge (credit)	496			359			25			(15		)	865
Cash payments	(424		)	(5,608		)	—			—			(6,032		)
Adjustments or non-cash credits including stock compensation expense	(55		)	(73		)	(25		)	—			(153		)
Restructuring liability as of September 30, 2013	$	17		$	13,880		$	—		$	5		$	13,902

Cash and Investments Cash and Investments (Tables)

9 Months Ended

Sep. 30, 2013

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 September 30, 2013 and December 31, 2012 (in thousands):



	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
As reported:
Cash and cash equivalents	$	92,016	$	—	$	—		$	92,016
Short-term investments	187,086		141		(24		)	187,203
Short-term restricted cash and investments	12,172		39		—			12,211
Long-term investments	157,437		63		(98		)	157,402
Long-term restricted cash and investments	15,830		59		—			15,889
Total cash and investments	$	464,541	$	302	$	(122	)	$	464,721



	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
As reported:
Cash and cash equivalents	$	170,070	$	—	$	(1	)	$	170,069
Short-term investments	241,391		46		(66		)	241,371
Short-term restricted cash and investments	12,242		4		—			12,246
Long-term investments	182,407		28		(124		)	182,311
Long-term restricted cash and investments	27,943		21		—			27,964
Total cash and investments	$	634,053	$	99	$	(191	)	$	633,961

Summary of Cash and Investments by Security Type

The following table summarizes our cash and cash equivalents and investments by security type as of September 30, 2013 and December 31, 2012 (in thousands):



	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and money market funds	$	62,645	$	—	$	—		$	62,645
Commercial paper	43,591		1		—			43,592
Corporate bonds	266,700		173		(122		)	266,751
U.S. Treasury and government sponsored enterprises	83,323		119		—			83,442
Municipal bonds	8,282		9		—			8,291
Total cash and investments	$	464,541	$	302	$	(122	)	$	464,721



	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and money market funds	$	81,744	$	2	$	—		$	81,746
Commercial paper	167,223		8		—			167,231
Corporate bonds	222,106		30		(187		)	221,949
U.S. Treasury and government sponsored enterprises	132,933		59		(1		)	132,991
Municipal bonds	30,047		—		(3		)	30,044
Total cash and investments	$	634,053	$	99	$	(191	)	$	633,961

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 September 30, 2013 (in thousands):



	Mature within One Year		After One Year through Two Years		Fair Value
Money market funds	$	58,102	$	—	$	58,102
Commercial paper	43,592		—		43,592
Corporate bonds	168,715		98,036		266,751
U.S. Treasury and government sponsored enterprises	71,279		12,163		83,442
Municipal bonds	2,212		6,079		8,291
Total	$	343,900	$	116,278	$	460,178

Inventory (Tables)

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Schedule of Inventory

Inventory consists of the following (in thousands):



	September 30, 2013		December 31, 2012
Raw materials	$	301	$	—
Work in process	1,374		—
Finished goods	89		—
Total	$	1,764	$	—

Debt (Tables)

9 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Schedule Of Debt

The amortized carrying amount of our debt consists of the following (in thousands):



	September 30, 2013			December 31, 2012
Convertible Senior Subordinated Notes due 2019	$	161,279		$	149,800
Secured Convertible Notes due 2015	97,428			100,676
Silicon Valley Bank term loan	80,000			80,000
Silicon Valley Bank line of credit	2,884			5,260
Total debt	341,591			335,736
Less: current portion	(12,127		)	(13,170		)
Long-term debt	$	329,464		$	322,566

Summary Of The Liability Component Of The 2019 Notes

The following is a summary of the liability component of the 2019 Notes as of September 30, 2013 (in thousands):



	September 30, 2013
Net carrying amount of the liability component	$	161,279
Unamortized discount of the liability component	126,221
Face amount of the 2019 Notes	$	287,500

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Fair Value Measurements Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Schedule Of Fair Value Of Financial Assets Measured On A Recurring Basis

The amounts presented exclude cash, but include investments classified as cash equivalents (in thousands):



	September 30, 2013
	Level 1		Level 2		Total
Money market funds	$	58,102	$	—	$	58,102
Commercial paper	—		43,592		43,592
Corporate bonds	—		266,751		266,751
U.S. Treasury and government sponsored enterprises	—		83,442		83,442
Municipal bonds	—		8,291		8,291
Total	$	58,102	$	402,076	$	460,178



	December 31, 2012
	Level 1		Level 2		Total
Money market funds	$	76,050	$	—	$	76,050
Commercial paper	—		167,231		167,231
Corporate bonds	—		221,949		221,949
U.S. Treasury and government sponsored enterprises	—		132,991		132,991
Municipal bonds	—		30,044		30,044
Total	$	76,050	$	552,215	$	628,265

Schedule Of Estimated Fair Value Of Outstanding Debt

The estimated fair values of our financial instruments that are carried at amortized cost for which it is practicable to determine a fair value were as follows (in thousands):



	September 30, 2013				December 31, 2012
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
2019 Notes	$	161,279	$	337,928	$	149,800	$	280,111
Silicon Valley Bank term loan	$	80,000	$	79,884	$	80,000	$	79,542
Silicon Valley Bank Line of Credit	$	2,884	$	2,884	$	5,260	$	5,253

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2013

Share-based Compensation [Abstract]

Schedule Of Allocated Employee Stock-Based Compensation Expenses

We recorded and allocated employee stock-based compensation expenses for our equity incentive plans and our 2000 Employee Stock Purchase Plan (“ESPP”) as follows (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Research and development expense	$	1,415	$	970	$	4,326	$	3,202
Selling, general and administrative expense	1,478		923		4,115		2,970
Restructuring-related stock-based compensation expense	—		—		49		—
Total employee stock-based compensation expense	$	2,893	$	1,893	$	8,490	$	6,172

Schedule Of Fair Value Of Employee Share-Based Payments Awards Estimated Using The 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
	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Weighted average grant-date fair value	$	2.99		$	3.31		$	2.92		$	3.27
Risk-free interest rate	1.57		%	0.81		%	1.47		%	0.82		%
Dividend yield	—		%	—		%	—		%	—		%
Volatility	60		%	69		%	60		%	69		%
Expected life	5.6 years			5.6 years			5.6 years			5.7 years



	Employee Stock Purchase Plan
	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Weighted average grant-date fair value	$	1.74		$	1.63		$	1.66		$	2.13
Risk-free interest rate	0.08		%	0.15		%	0.12		%	0.10		%
Dividend yield	—		%	—		%	—		%	—		%
Volatility	67		%	68		%	67		%	68		%
Expected life	0.5 years			0.5 years			0.5 years			0.5 years

Summary Of All Stock Option Activity

A summary of all stock option activity for the nine months ended September 30, 2013 is presented below (dollars in thousands, except per share amounts):



	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Options outstanding at December 31, 2012	18,448,550		$	6.85
Granted	5,778,323		$	5.38
Exercised	(4,473	)	$	4.42
Forfeited	(712,885	)	$	6.42
Options outstanding at September 30, 2013	23,509,515		$	6.50	4.71	$	5,709
Exercisable at September 30, 2013	13,803,103		$	7.23	3.51	$	2,376

Summary Of All RSU Activity

A summary of all restricted stock unit (“RSU”) activity for the nine months ended September 30, 2013 is presented below (dollars in thousands, except per share amounts):



	Shares		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Awards outstanding at December 31, 2012	1,294,621		$	6.07
Awarded	1,058,668		$	5.44
Released	(230,059	)	$	7.34
Forfeited	(72,132	)	$	5.48
Awards outstanding at September 30, 2013	2,051,098		$	5.62	1.98	$	11,855

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2013

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):



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Numerator:
Net loss	$	(67,124	)	$	(32,814	)	$	(174,014	)	$	(95,452	)
Denominator:
Shares used in computing basic and diluted net loss per share	184,149			166,354			183,957			152,316
Net loss per share, basic and diluted	$	(0.36	)	$	(0.20	)	$	(0.95	)	$	(0.63	)

Schedule Of Potential Shares Of Common Stock Not Included In Computation Of Diluted Net Loss Per Share



	September 30
	2013	2012
Convertible debt	54,123	54,123
Outstanding stock options, unvested RSUs and ESPP contributions	25,694	15,839
Warrants	1,441	1,441
Total potentially dilutive shares	81,258	71,403

Concentrations of Credit Risk (Tables)

9 Months Ended

Sep. 30, 2013

Risks and Uncertainties [Abstract]

Schedules of collaborators that represent 10% or more of total revenues



	Nine Months Ended September 30,
	2013		2012
Collaborator:
Bristol-Myers Squibb	60	%	59	%
Merck	—	%	27	%
Daiichi Sankyo	—	%	14	%
Pharmacy:
Diplomat Specialty Pharmacy	36	%	—	%

Organization and Summary of Significant Accounting Policies (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2013 phase segment	Dec. 31, 2012
Operations [Line Items]
Number of Phases in Process \| phase	2
Annual Operating Cycle	P52W	P52W
Number of Operating Segments \| segment	1
Sales Revenue, Percent Discount for Prompt Payment	2.00%
Glaxo Smith Kline [Member]
Operations [Line Items]
Percent of royalty on net sale	3.00%
Minimum [Member]
Operations [Line Items]
Annual Operating Cycle	P52W
Maximum [Member]
Operations [Line Items]
Annual Operating Cycle	P53W

Restructurings (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended	45 Months Ended
Restructurings (Narrative) (Details) $ in Thousands	Sep. 30, 2013 USD ($) employee	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($) employee	Sep. 30, 2012 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2013 USD ($) employee	Dec. 31, 2011 USD ($)
Restructuring Cost and Reserve [Line Items]
Aggregate reduction in headcount \| employee	429		429			429
Restructuring charge (credit)	$ 137	$ 733	$ 865	$ 1,704	$ 9,171	$ 52,900
Proceeds from sale of property and equipment			40	877	938
Restructuring Reserve	13,902		13,902		19,222	13,902	$ 13,978
Expected additional payment for restructuring			1,800
Restructuring Reserve, Settled with Cash			6,032		6,267	34,800
Proceeds from Subtenants						9,100
Total Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Cash Settlement Net of Proceeds	2,100	$ 2,200	6,000	$ 4,500
Credit for New Sublease [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)	700
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)			359		8,276	28,900
Proceeds from sale of property and equipment					0
Restructuring Reserve	13,880		13,880		19,202	13,880	13,921
Restructuring Reserve, Settled with Cash			5,608		5,299
Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)			496		970	21,700
Proceeds from sale of property and equipment					0
Restructuring Reserve	17		17		0	17	6
Restructuring Reserve, Settled with Cash			424		965
Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)			25		(47)	2,200
Proceeds from sale of property and equipment					938	2,600
Restructuring Reserve	$ 0		0		0	$ 0	$ 0
Restructuring Reserve, Settled with Cash			$ 0		$ 0

Restructurings (Summary of Components of Restructuring Liability) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended	45 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013
Restructuring Reserve [Roll Forward]
Restructuring liability			$ 19,222	$ 13,978	$ 13,978
Restructuring charge (credit)	$ 137	$ 733	865	1,704	9,171	$ 52,900
Cash payments			(6,032)		(6,267)	(34,800)
Adjustments or non-cash credits including stock compensation expense			(153)		1,402
Proceeds from sale of assets			40	877	938
Restructuring liability	13,902		13,902		19,222	13,902
Employee Severance And Other Benefits [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability			0	6	6
Restructuring charge (credit)			496		970	21,700
Cash payments			(424)		(965)
Adjustments or non-cash credits including stock compensation expense			(55)		(11)
Proceeds from sale of assets					0
Restructuring liability	17		17		0	17
Facility Charges [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability			19,202	13,921	13,921
Restructuring charge (credit)			359		8,276	28,900
Cash payments			(5,608)		(5,299)
Adjustments or non-cash credits including stock compensation expense			(73)		2,304
Proceeds from sale of assets					0
Restructuring liability	13,880		13,880		19,202	13,880
Asset Impairment [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability			0	0	0
Restructuring charge (credit)			25		(47)	2,200
Cash payments			0		0
Adjustments or non-cash credits including stock compensation expense			(25)		(891)
Proceeds from sale of assets					938	2,600
Restructuring liability	0		0		0	0
Credit for New Sublease [Member]
Restructuring Reserve [Roll Forward]
Restructuring charge (credit)	700
Legal And Other Fees [Member]
Restructuring Reserve [Roll Forward]
Restructuring liability			20	$ 51	51
Restructuring charge (credit)			(15)		(28)
Cash payments			0		(3)
Adjustments or non-cash credits including stock compensation expense			0		0
Proceeds from sale of assets					0
Restructuring liability	$ 5		$ 5		$ 20	$ 5

Cash and Investments Cash and Investments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2013 USD ($) investment	Dec. 31, 2012 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 464,541	$ 634,053
Gross Unrealized Gains	302	99
Gross Unrealized Losses	(122)	(191)
Fair Value	464,721	633,961
Unrealized loss position	$ 106,800
Number of investments in an unrealized loss position \| investment	53
Unrealized loss position of all securities in years	1 year
Silicon Valley Bank Loan And Security Agreement [Member]
Schedule of Available-for-sale Securities [Line Items]
Collateral balance	$ 84,500	87,000
Cash and cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	92,016	170,070
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	92,016	170,069
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	187,086	241,391
Gross Unrealized Gains	141	46
Gross Unrealized Losses	(24)	(66)
Fair Value	187,203	241,371
Short-term restricted cash and investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,172	12,242
Gross Unrealized Gains	39	4
Gross Unrealized Losses	0	0
Fair Value	12,211	12,246
Long-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	157,437	182,407
Gross Unrealized Gains	63	28
Gross Unrealized Losses	(98)	(124)
Fair Value	157,402	182,311
Long-term restricted cash and investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,830	27,943
Gross Unrealized Gains	59	21
Gross Unrealized Losses	0	0
Fair Value	15,889	27,964
Cash and money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	62,645	81,744
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	0
Fair Value	62,645	81,746
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	58,102
Mature within One Year	58,102
After One Year through Two Years	0
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	43,591	167,223
Gross Unrealized Gains	1	8
Gross Unrealized Losses	0	0
Fair Value	43,592	167,231
Mature within One Year	43,592
After One Year through Two Years	0
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	266,700	222,106
Gross Unrealized Gains	173	30
Gross Unrealized Losses	(122)	(187)
Fair Value	266,751	221,949
Unrealized loss position	105,800
Mature within One Year	168,715
After One Year through Two Years	98,036
U.S. Treasury and government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	83,323	132,933
Gross Unrealized Gains	119	59
Gross Unrealized Losses	0	(1)
Fair Value	83,442	132,991
Mature within One Year	71,279
After One Year through Two Years	12,163
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,282	30,047
Gross Unrealized Gains	9	0
Gross Unrealized Losses	0	(3)
Fair Value	8,291	$ 30,044
Mature within One Year	2,212
After One Year through Two Years	6,079
Investments, excluding cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	460,178
Mature within One Year	343,900
After One Year through Two Years	$ 116,278

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 301	$ 0
Work in process	1,374	0
Finished goods	89	0
Total	$ 1,764	$ 0

Debt (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
Debt (Narrative) (Details) - USD ($)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Aug. 31, 2012	Aug. 14, 2012	Jun. 30, 2010
Senior Subordinated Notes [Member] \| 4.25% Convertible Senior Subordinated Notes due August 15, 2019 [Member]
Debt Instrument [Line Items]
Debt, interest rate							4.25%
Debt, principal amount	$ 287,500,000		$ 287,500,000			$ 287,500,000
Interest Expense, Debt	7,200,000	$ 3,400,000	21,200,000	$ 3,400,000
Interest Expense, Coupon Interest	3,100,000	1,500,000	9,200,000	1,500,000
Amortization of Financing Costs and Discounts	4,100,000	1,900,000	12,000,000	1,900,000
Balance of unamortized closing fees and expenses	4,100,000		4,100,000		$ 4,700,000
Convertible Debt	161,279,000		161,279,000		149,800,000
Secured Convertible Notes Due June 2015 [Member] \| Deerfield Financing [Member]
Debt Instrument [Line Items]
Debt, principal amount								$ 124,000,000.0
Interest Expense, Debt	4,100,000	4,100,000	11,900,000	11,700,000
Amortization of Financing Costs and Discounts	2,600,000	$ 2,500,000	7,400,000	$ 7,200,000
Balance of unamortized closing fees and expenses	1,600,000		1,600,000		2,300,000
Convertible Debt	$ 114,000,000		$ 114,000,000		$ 124,000,000

Debt (Schedule Of Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Total debt	$ 341,591	$ 335,736
Less: current portion	(12,127)	(13,170)
Long-term debt	329,464	322,566
Senior Subordinated Notes [Member] \| Convertible Senior Subordinated Notes due 2019 [Member]
Debt Instrument [Line Items]
Convertible Debt	161,279	149,800
Secured Debt [Member] \| Deerfield Notes [Member]
Debt Instrument [Line Items]
Convertible Debt	97,428	100,676
Term Loan [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Debt Instrument [Line Items]
Silicon Valley Bank term loan	80,000	80,000
Line of Credit [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Debt Instrument [Line Items]
Silicon Valley Bank Line of Credit	$ 2,884	$ 5,260

Debt (2019 Notes) (Details) - Senior Subordinated Notes [Member] - 4.25% Convertible Senior Subordinated Notes due August 15, 2019 [Member] - USD ($)	Sep. 30, 2013	Dec. 31, 2012	Aug. 31, 2012
Debt Instrument [Line Items]
Net carrying amount of the liability component	$ 161,279,000	$ 149,800,000
Unamortized discount of the liability component	126,221,000
Face amount	$ 287,500,000		$ 287,500,000

Fair Value Measurements (Schedule of Estimated Fair Value of Outstanding Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Carrying Amount [Member] \| Senior Subordinated Notes [Member] \| 2019 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 161,279	$ 149,800
Carrying Amount [Member] \| Term Loan [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	80,000	80,000
Carrying Amount [Member] \| Line of Credit [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	2,884	5,260
Fair Value [Member] \| Senior Subordinated Notes [Member] \| 2019 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	337,928	280,111
Fair Value [Member] \| Term Loan [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	79,884	79,542
Fair Value [Member] \| Line of Credit [Member] \| Silicon Valley Bank term loan and Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 2,884	$ 5,253

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, in shares	23,509,515	18,448,550
Performance Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, in shares	3,720,752
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 24.4
Unrecognized compensation expense, weighted-average period for recognition (in years)	2 years 11 months 1 day
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 8.0
Unrecognized compensation expense, weighted-average period for recognition (in years)	3 years 3 months 29 days

Stock-Based Compensation (Schedule of Allocated Employee Stock-Based Compensation Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	$ 2,893	$ 1,893	$ 8,490	$ 6,172
Research and development expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	1,415	970	4,326	3,202
Selling, general and administrative expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	1,478	923	4,115	2,970
Restructuring Charges [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation expense	$ 0	$ 0	$ 49	$ 0

Stock-Based Compensation (Schedule of Fair Value of Employee Share-Based Payments Awards Estimated Using the Assumptions and Weighted Average Fair Values) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value	$ 2.99	$ 3.31	$ 2.92	$ 3.27
Risk-free interest rate	1.57%	0.81%	1.47%	0.82%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	60.00%	69.00%	60.00%	69.00%
Expected life	5 years 7 months 6 days	5 years 7 months 6 days	5 years 7 months 6 days	5 years 8 months 12 days
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value	$ 1.74	$ 1.63	$ 1.66	$ 2.13
Risk-free interest rate	0.08%	0.15%	0.12%	0.10%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	67.00%	68.00%	67.00%	68.00%
Expected life	6 months	6 months	6 months	6 months

Stock-Based Compensation (Summary of All Stock Option Activity) (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2013 USD ($) $ / shares shares
Shares [Roll Forward]
Options outstanding at beginning of period, Shares \| shares	18,448,550
Granted, Shares \| shares	5,778,323
Exercised, Shares \| shares	(4,473)
Forfeited, Shares \| shares	(712,885)
Options outstanding at end of period, Shares \| shares	23,509,515
Exercisable at end of period, Shares \| shares	13,803,103
Weighted Average Exercise Price [Roll Forward]
Options outstanding at beginning of period, Weighted Average Exercise Price \| $ / shares	$ 6.85
Granted, Weighted Average Exercise Price \| $ / shares	5.38
Exercised, Weighted Average Exercise Price \| $ / shares	4.42
Forfeited, Weighted Average Exercise Price \| $ / shares	6.42
Options outstanding at end of period, Weighted Average Exercise Price \| $ / shares	6.50
Exercisable at end of period, Weighted Average Exercise Price \| $ / shares	$ 7.23
Options outstanding at end of period, Weighted Average Remaining Contractual Term	4 years 8 months 16 days
Exercisable at end of period, Weighted Average Remaining Contractual Term	3 years 6 months 4 days
Options outstanding at end of period, Aggregate Intrinsic Value, in dollars \| $	$ 5,709
Exercisable at end of period, Aggregate Intrinsic Value, in dollars \| $	$ 2,376

Stock-Based Compensation (Summary of All RSU Activity) (Details) - Restricted Stock Units (RSUs) [Member] $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2013 USD ($) $ / shares shares
Shares [Roll Forward]
RSUs outstanding at beginning of period, Shares \| shares	1,294,621
Awarded, Shares \| shares	1,058,668
Released, Shares \| shares	(230,059)
Forfeited, Shares \| shares	(72,132)
RSUs outstanding at end of period, Shares \| shares	2,051,098
Weighted Average Grant DateFair Value [Roll Forward]
RSUs outstanding at beginning of period, Weighted Average Grant Date Fair Value \| $ / shares	$ 6.07
Awarded, Weighted Average Grant Date Fair Value \| $ / shares	5.44
Released, Weighted Average Grant Date Fair Value \| $ / shares	7.34
Forfeited, Weighted Average Grant Date Fair Value \| $ / shares	5.48
RSUs outstanding at end of period, Weighted Average Grant Date Fair Value \| $ / shares	$ 5.62
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms	1 year 11 months 23 days
RSUs outstanding at end of period, Aggregate Intrinsic Value, in dollars \| $	$ 11,855

Income Taxes (Details) $ in Millions	12 Months Ended
Income Taxes (Details) $ in Millions	Dec. 31, 2012 USD ($)
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 1,007
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	880
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	$ 26
Minimum [Member] \| Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2018
Minimum [Member] \| State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2013
Maximum [Member] \| Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2032
Maximum [Member] \| State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2032

Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net loss, in dollars	$ (67,124)	$ (32,814)	$ (174,014)	$ (95,452)
Shares used in computing basic and diluted net loss per share	184,149	166,354	183,957	152,316
Net loss per share, basic and diluted, in dollars per share	$ (0.36)	$ (0.20)	$ (0.95)	$ (0.63)
Potentially dilutive shares			81,258	71,403
Convertible debt [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares			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			25,694	15,839
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares			1,441	1,441

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Concentrations of Credit Risk (Details)	3 Months Ended		9 Months Ended
Concentrations of Credit Risk (Details)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Sobi [Member] \| Accounts Receivable [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			14.00%
Bristol-Myers Squibb [Member] \| Revenue, Rights Granted [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			60.00%	59.00%
Merck [Member] \| Revenue, Rights Granted [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			0.00%	27.00%
Daiichi Sankyo [Member] \| Revenue, Rights Granted [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			0.00%	14.00%
Diplomat Specialty Pharmacy [Member] \| Accounts Receivable [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			55.00%
Diplomat Specialty Pharmacy [Member] \| Sales Revenue, Goods, Net [Member] \| Revenue from Rights Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage			36.00%	0.00%
UNITED STATES \| Sales [Member] \| Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	87.00%	100.00%	96.00%	100.00%

Fair Value Measurements (Schedule Of Fair Value Of Financial Assets Measured On A Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	$ 58,102	$ 76,050
Level 1 [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	58,102	76,050
Level 1 [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Level 1 [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of 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 fair value of financial assets	0	0
Level 1 [Member] \| Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	402,076	552,215
Level 2 [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	0
Level 2 [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	43,592	167,231
Level 2 [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	266,751	221,949
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 fair value of financial assets	83,442	132,991
Level 2 [Member] \| Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	8,291	30,044
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	460,178	628,265
Estimate of Fair Value, Fair Value Disclosure [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	58,102	76,050
Estimate of Fair Value, Fair Value Disclosure [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	43,592	167,231
Estimate of Fair Value, Fair Value Disclosure [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	266,751	221,949
Estimate of Fair Value, Fair Value Disclosure [Member] \| U.S. Treasury and government sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	83,442	132,991
Estimate of Fair Value, Fair Value Disclosure [Member] \| Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of financial assets	$ 8,291	$ 30,044