Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2013	Feb. 20, 2014	Jun. 28, 2013
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Trading Symbol	NKTR
Entity Registrant Name	NEKTAR THERAPEUTICS
Entity Central Index Key	0000906709
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		126,645,285
Entity Public Float			$ 1,330,867,461

Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 39,067	$ 25,437
Short-term investments	197,959	251,757
Accounts receivable, net of allowance of nil at December 31, 2013 and 2012	2,229	5,805
Inventory	13,452	18,269
Other current assets	5,175	13,363
Total current assets	257,882	314,631
Restricted Cash	25,000	25,000
Property and equipment, net	66,974	72,215
Goodwill	76,501	76,501
Other assets	8,170	9,443
Total assets	434,527	497,790
Current liabilities:
Accounts payable	9,115	2,863
Accrued compensation	14,254	8,773
Accrued expenses	6,243	8,008
Accrued clinical trial expenses	16,905	17,500
Deferred revenue, current portion	23,664	21,896
Interest payable	6,917	7,083
Liability related to the sale of future royalties, current portion	7,000	3,000
Other current liabilities	14,123	9,414
Total current liabilities	98,221	78,537
Senior secured notes	125,000	125,000
Capital lease obligations, less current portion	8,049	11,607
Liability related to receipt of refundable milestone payment	70,000
Liability related to the sale of future royalties, less current portion	121,520	128,266
Deferred revenue, less current portion	82,384	96,551
Other long-term liabilities	19,256	10,811
Total liabilities	524,430	450,772
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock, 10,000 shares authorized, $0.0001 par value; no shares designated, issued or outstanding at December 31, 2013 and 2012
Common stock, $0.0001 par value; 300,000 authorized; 116,494 shares and 115,259 shares issued and outstanding at December 31, 2013 and 2012, respectively	11	11
Capital in excess of par value	1,643,660	1,617,744
Accumulated other comprehensive loss	(1,181)	(357)
Accumulated deficit	(1,732,393)	(1,570,380)
Total stockholders' equity (deficit)	(89,903)	47,018
Total liabilities and stockholders' equity (deficit)	$ 434,527	$ 497,790

Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Allowance for accounts receivable
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares designated	0	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	116,494	115,259
Common stock, shares outstanding	116,494	115,259

Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:
Product sales	$ 44,846	$ 35,399	$ 24,864
Royalty revenue	1,148	4,874	10,327
Non-cash royalty revenue related to sale of future royalties	22,055	10,791
License, collaboration and other revenue	80,872	30,127	36,289
Total revenue	148,921	81,191	71,480
Operating costs and expenses:
Cost of goods sold	38,509	30,428	21,891
Research and development	190,010	148,675	126,766
General and administrative	40,532	41,614	46,760
Impairment of long-lived assets		1,675
Total operating costs and expenses	269,051	222,392	195,417
Loss from operations	(120,130)	(141,201)	(123,937)
Non-operating income (expense):
Interest income	732	2,315	2,244
Interest expense	(18,453)	(15,489)	(10,223)
Non-cash interest expense on liability related to sale of future royalties	(22,309)	(18,057)
Other income (expense), net	392	983	(1,044)
Total non-operating expense, net	(39,638)	(30,248)	(9,023)
Loss before provision for income taxes	(159,768)	(171,449)	(132,960)
Provision for income taxes	2,245	406	1,018
Net loss	$ (162,013)	$ (171,855)	$ (133,978)
Basic and diluted net loss per share	$ (1.40)	$ (1.50)	$ (1.19)
Weighted average shares outstanding used in computing basic and diluted net loss per share	115,732	114,820	112,942

Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (162,013)	$ (171,855)	$ (133,978)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale investments	(268)	1,206	(783)
Income tax provision (benefit) on unrealized gain on available-for-sale investments	470	(470)
Net foreign currency translation gain (loss)	(1,026)	10	(1,288)
Other comprehensive income (loss), net of tax	(824)	746	(2,071)
Comprehensive loss	$ (162,837)	$ (171,109)	$ (136,049)

- 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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 20

-Article 9

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

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 4: 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 5: 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 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.19)

-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

-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 8: 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 9: 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 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 5

+ Details

Consolidated Statements of Stockholders' Equity (Deficit) (USD $) In Thousands	Total	Common Shares [Member]	Capital in Excess of Par Value [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2010	$ 90,662	$ 9	$ 1,354,232	$ 968	$ (1,264,547)
Beginning Balance, Shares at Dec. 31, 2010		94,517
Sale of common stock, net of issuance costs of $617	219,783	2	219,781
Sale of common stock, Shares		19,000
Shares issued under equity compensation plans	4,530		4,530
Shares issued under equity compensation plans, Shares		968
Stock-based compensation	18,885		18,885
Other comprehensive income/(loss)	(2,071)			(2,071)
Net loss	(133,978)				(133,978)
Ending Balance at Dec. 31, 2011	197,811	11	1,597,428	(1,103)	(1,398,525)
Ending Balance, Shares at Dec. 31, 2011		114,485
Shares issued under equity compensation plans	4,117		4,117
Shares issued under equity compensation plans, Shares		774
Stock-based compensation	16,199		16,199
Other comprehensive income/(loss)	746			746
Net loss	(171,855)				(171,855)
Ending Balance at Dec. 31, 2012	47,018	11	1,617,744	(357)	(1,570,380)
Ending Balance, Shares at Dec. 31, 2012		115,259
Shares issued under equity compensation plans	8,208		8,208
Shares issued under equity compensation plans, Shares		1,235
Stock-based compensation	17,708		17,708
Other comprehensive income/(loss)	(824)			(824)
Net loss	(162,013)				(162,013)
Ending Balance at Dec. 31, 2013	$ (89,903)	$ 11	$ 1,643,660	$ (1,181)	$ (1,732,393)
Ending Balance, Shares at Dec. 31, 2013		116,494

- Definition

This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

+ References+ Details

- Definition

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

+ References

+ Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References+ Details

- Definition

Value of stock (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of stock value of such awards forfeited. Stock issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

+ References+ Details

Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net loss	$ (162,013)	$ (171,855)	$ (133,978)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(22,055)	(10,791)
Non-cash interest expense on liability related to sale of future royalties	22,309	18,057
Stock-based compensation	17,708	16,199	18,885
Depreciation and amortization	14,275	14,508	14,951
Impairment of long-lived assets		1,675
Other non-cash transactions	664	845	1,359
Changes in assets and liabilities:
Accounts receivable, net	3,576	(867)	20,164
Inventory	4,817	(5,613)	(5,390)
Other assets	6,423	6,031	(12,267)
Accounts payable	6,199	(122)	(3,384)
Accrued compensation	5,481	(4,034)	3,555
Accrued expenses	(1,915)	1,495	1,013
Accrued clinical trial expenses	(595)	5,547	(191)
Deferred revenue	(12,399)	(9,384)	(17,516)
Interest payable	(166)	5,278
Liability related to receipt of refundable milestone payment	70,000
Other liabilities	9,164	3,275	(943)
Net cash used in operating activities	(38,527)	(129,756)	(113,742)
Cash flows from investing activities:
Maturities of investments	319,181	307,887	383,052
Purchases of investments	(268,068)	(164,662)	(695,371)
Sales of investments	2,887	5,378	210,089
Restricted cash		(25,000)
Purchases of property and equipment	(4,091)	(10,583)	(9,722)
Net cash provided by (used in) investing activities	49,909	113,020	(111,952)
Cash flows from financing activities:
Payment of capital lease obligations	(2,992)	(2,437)	(1,978)
(Repayment of) proceeds from sale of future royalties, net of $4.4 million of transaction costs in 2012	(3,000)	119,588
Proceeds from issuance of senior secured notes, net of $4.5 million of issuance costs		77,940
Repayment of convertible subordinated notes		(172,407)
Proceeds from shares issued under equity compensation plans	8,208	4,117	4,530
Issuance of common stock, net of issuance costs			219,783
Net cash provided by financing activities	2,216	26,801	222,335
Effect of exchange rates on cash and cash equivalents	32	60	916
Net increase (decrease) in cash and cash equivalents	13,630	10,125	(2,443)
Cash and cash equivalents at beginning of year	25,437	15,312	17,755
Cash and cash equivalents at end of year	39,067	25,437	15,312
Supplemental disclosure of cash flow information:
Cash paid for interest	17,590	9,620	10,277
Cash paid for income taxes	1,014	1,021	957
Supplemental schedule of non-cash investing and financing activities:
Retirement of convertible subordinated notes in exchange for senior secured notes		$ 42,548

Organization and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Organization and Summary of Significant Accounting Policies

Note 1 — Organization and Summary of Significant Accounting Policies

Organization

We are a clinical-stage biopharmaceutical company headquartered in San Francisco, California and incorporated in Delaware. We are developing a pipeline of drug candidates that utilize our PEGylation and advanced polymer conjugate technology platforms with the objective to improve the benefits of drugs for patients.

Our research and development activities have required significant resources to date and are expected to continue to require significant resources. As a result, we expect to continue to incur substantial losses and negative cash flows from operations in the future. We have financed our operations primarily through cash from licensing, collaboration and manufacturing agreements as well as financing transactions. At December 31, 2013, we had approximately $262.0 million in cash, cash equivalents and investments in marketable securities, of which $25.0 million was restricted, and $160.8 million in indebtedness. The indebtedness includes $125.0 million in aggregate principal amount of 12.0% senior secured notes due July 15, 2017, but excludes our long-term liability relating to the sale of future royalties. As is further described in Note 7, this royalty obligation liability will not be settled in cash, but we expect to make a payment of $7.0 million to the royalty purchaser in 2014 as a certain specified worldwide net sales threshold of MIRCERA^® is not expected to be met.

Basis of Presentation, Principles of Consolidation and Use of Estimates

Our consolidated financial statements include the financial position, results of operations and cash flows of our wholly-owned subsidiaries: Nektar Therapeutics (India) Private Limited and Nektar Therapeutics UK, Ltd. (Nektar UK). All intercompany accounts and transactions have been eliminated in consolidation.

Our consolidated financial statements are denominated in U.S. dollars. Accordingly, changes in exchange rates between the applicable foreign currency and the U.S. dollar will affect the translation of each foreign subsidiary’s financial results into U.S. dollars for purposes of reporting our consolidated financial results. Translation gains and losses are included in accumulated other comprehensive income (loss) in the stockholders’ equity (deficit) section of the balance sheet. To date, such cumulative translation adjustments have not been material to our consolidated financial position. Aggregate gross foreign currency transaction gains (losses) recorded in operations for the years ended December 31, 2013, 2012, and 2011 were not material.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. On an ongoing basis, we evaluate our estimates, including those related to deferred revenue recognition periods, inventories, the impairment of investments, the impairment of goodwill and long-lived assets, contingencies, estimated interest expense from our liability related to our sale of future royalties, stock-based compensation, and ongoing litigation, amongst other estimates. We base our estimates on historical experience and on other assumptions that management believes are reasonable under the circumstances. These estimates also form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources.

Reclassifications

Certain items previously reported in specific financial statement captions have been reclassified to conform to the current period presentation. Such reclassifications do not materially impact previously reported total revenue, operating loss or net loss or total assets, liabilities or stockholders’ equity (deficit).

Cash, Cash Equivalents, and Investments, and Fair Value of Financial Instruments

We consider all investments in marketable securities with an original maturity of three months or less when purchased to be cash equivalents. Investments in securities with remaining maturities of less than one year, or where our intent is to use the investments to fund current operations or to make them available for current operations, are classified as short-term investments.

Investments are designated as available-for-sale and are carried at fair value, with unrealized gains and losses reported in stockholders’ equity (deficit) as accumulated other comprehensive income (loss). The disclosed fair value related to our cash equivalents and investments is based primarily on the reported fair values in our period-end brokerage statements, which are based on market prices from a variety of industry standard data providers and generally represent quoted prices for similar assets in active markets or have been derived from observable market data. We independently validate these fair values using available market quotes and other information.

Interest and dividends on securities classified as available-for-sale, as well as amortization of premiums and accretion of discounts to maturity, are included in interest income. Realized gains and losses and declines in value of available-for-sale securities judged to be other-than-temporary, if any, are included in other income (expense). The cost of securities sold is based on the specific identification method.

Accounts Receivable and Significant Customer Concentrations

Our customers are primarily pharmaceutical and biotechnology companies that are located in the U.S. and Europe. Our accounts receivable balance contains billed and unbilled trade receivables from product sales and royalties, as well as time and materials based billings from collaborative research and development agreements. When appropriate, we provide for an allowance for doubtful accounts by reserving for specifically identified doubtful accounts. We generally do not require collateral from our customers. We perform a regular review of our customers’ payment histories and associated credit risk. We have not experienced significant credit losses from our accounts receivable. At December 31, 2013, three different customers represented 30%, 28%, and 28%, respectively, of our accounts receivable. At December 31, 2012, four different customers represented 38%, 27%, 14% and 11%, respectively, of our accounts receivable.

Inventory and Significant Supplier Concentrations

Inventory is generally manufactured upon receipt of firm purchase orders from our collaboration partners. Inventory includes direct materials, direct labor, and manufacturing overhead and cost is determined on a first-in, first-out basis. Inventory is valued at the lower of cost or market and defective or excess inventory is written down to net realizable value based on historical experience or projected usage. Inventory related to research and development activities is expensed when purchased.

We are dependent on our suppliers and contract manufacturers to provide raw materials, drugs and devices of appropriate quality and reliability and to meet applicable contract and regulatory requirements. In certain cases, we rely on single sources of supply of one or more critical materials. Consequently, in the event that supplies are delayed or interrupted for any reason, our ability to develop and produce our drug candidates or our ability to meet our supply obligations could be significantly impaired, which could have a material adverse effect on our business, financial condition and results of operations.

Property and Equipment

Property and equipment are stated at cost. Major improvements are capitalized, while maintenance and repairs are expensed when incurred. Manufacturing, laboratory and other equipment are depreciated using the straight-line method generally over estimated useful lives of three to seven years. Leasehold improvements and buildings are depreciated using the straight-line method over the shorter of the estimated useful life or the remaining term of the lease.

We periodically review our property and equipment for recoverability whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Generally, an impairment loss would be recognized if the carrying amount of an asset exceeds the sum of the discounted cash flows expected to result from the use and eventual disposal of the asset.

Goodwill

Goodwill represents the excess of the price paid for another entity over the fair value of the assets acquired and liabilities assumed in a business combination. We test for impairment in the fourth quarter of each year using an October 1 measurement date, as well as at other times when impairment indicators exist or when events occur or circumstances change that would indicate the carrying amount may not be fully recoverable.

We are organized in one reporting unit and have evaluated the goodwill for the Company as a whole. In order to test for goodwill impairment, we first assess qualitative factors to determine whether it is more likely than not that the fair value of our single reporting unit is less than its carrying amount and, if so, we perform a two-step goodwill impairment test. The first step, identifying a potential impairment, compares the fair value of the reporting unit with its carrying amount. If the carrying amount exceeds its fair value, the second step compares the book value of our assigned goodwill to its implied fair value. We did not recognize any goodwill-related impairment charges during 2013, 2012, or 2011.

Revenue Recognition

We enter into arrangements with pharmaceutical and biotechnology collaboration partners that may involve multiple deliverables. Our arrangements may contain one or more of the following elements: upfront fees, contract research and development, milestone payments, manufacturing and supply payments, royalties, and license fees. Each deliverable in the arrangement is evaluated to determine whether it meets the criteria to be accounted for as a separate unit of accounting or whether it should be combined with other deliverables. Revenue is recognized separately for each element.

At the inception of each new multiple-element arrangement or the material modification of an existing multiple-element arrangement, we allocate all consideration received under multiple-element arrangements to all units of accounting based on the relative selling price method, generally based on our best estimate of selling price (ESP). The objective of ESP is to determine the price at which we would transact a sale if the product or service was sold on a stand-alone basis. We determine ESP for the elements in our collaboration arrangements by considering multiple factors including, but not limited to, technical complexity of the performance obligation and similarity of elements to those performed under previous arrangements. Since we apply significant judgment in arriving at the ESPs, any material change in our estimates would significantly affect the allocation of the total consideration to the different elements of a multiple element arrangement.

Product sales

Product sales are primarily derived from cost-plus and fixed price manufacturing and supply agreements with our collaboration partners and revenue is recognized when there is persuasive evidence that an arrangement exists, delivery has occurred, the price is fixed or determinable, and collection is reasonably assured. We have not experienced any significant returns from our customers.

Royalty revenues

Generally, we are entitled to royalties from our partners based on the net sales of their approved drugs that are marketed and sold in one or more countries where we hold royalty rights. We recognize royalty revenue when the cash is received or when the royalty amount to be received is estimable and collection is reasonably assured. With respect to the non-cash royalties related to sale of future royalties described at Note 7, revenue is recognized when estimable, otherwise, revenue is recognized during the period in which the related royalty report is received, which generally occurs in the quarter after the applicable product sales are made.

License, collaboration and other

Upfront fees received by us in license and collaboration arrangements that include future obligations, such as manufacturing and supply obligations, are recognized ratably over our expected performance period under each respective arrangement. We make our best estimate of the period over which we expect to fulfill our performance obligations, which may include technology transfer assistance, research activities, clinical development activities, and manufacturing activities from development through the commercialization of the product. Given the uncertainties of these collaboration arrangements, significant judgment is required to determine the duration of the performance period.

Contingent consideration received from the achievement of a substantive milestone is recognized in its entirety in the period in which the milestone is achieved, which we believe is consistent with the substance of our performance under our various license and collaboration agreements. A milestone is defined as an event (i) that can only be achieved based in whole or in part either on the entity’s performance or on the occurrence of a specific outcome resulting from the entity’s performance, (ii) for which there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved, and (iii) that would result in additional payments being due to the entity. A milestone is substantive if the consideration earned from the achievement of the milestone is consistent with our performance required to achieve the milestone or the increase in value to the collaboration resulting from our performance, relates solely to our past performance, and is reasonable relative to all of the other deliverables and payments within the arrangement.

Our license and collaboration agreements with our partners provide for payments to us upon the achievement of development milestones, such as the completion of clinical trials or regulatory submissions, approvals by health authorities, and commercial launches of drugs. Given the challenges inherent in developing and obtaining regulatory approval for drug products and in achieving commercial launches, there was substantial uncertainty whether any such milestones would be achieved at the time of execution of these licensing and collaboration agreements. In addition, we evaluated whether the development milestones meet the remaining criteria to be considered substantive. As a result of our analysis, we consider our remaining development milestones under all of our license and collaboration agreements to be substantive and, accordingly, we expect to recognize as revenue future payments received from such milestones only if and as each milestone is achieved.

Our license and collaboration agreements with certain partners also provide for contingent payments to us based solely upon the performance of the respective partner. For such contingent amounts we expect to recognize the payments as revenue when earned under the applicable contract, which is generally upon completion of performance by the respective partner, provided that collection is reasonably assured.

Our license and collaboration agreements with our partners also provide for payments to us upon the achievement of specified sales volumes of approved drugs. We consider these payments to be similar to royalty payments and we will recognize such sales-based payments upon achievement of such sales volumes, provided that collection is reasonably assured.

Shipping and Handling Costs

We recognize costs related to shipping and handling of product to customers in cost of goods sold.

Stock-Based Compensation

Stock-based compensation arrangements include stock option grants and restricted stock unit (RSU) awards under our equity incentive plans, as well as shares issued under our Employee Stock Purchase Plan (ESPP), through which employees may purchase our common stock at a discount to the market price.

We use the Black-Scholes option valuation model for the respective grant to determine the estimated fair value of the option on the date of grant (grant date fair value) and the estimated fair value of common stock purchased under the ESPP. The Black-Scholes option pricing model requires the input of highly subjective assumptions. Because our employee stock options have characteristics significantly different from those of traded options, and because changes in the subjective input assumptions can materially affect the fair value estimate, in management’s opinion, the existing models may not provide a reliable single measure of the fair value of our employee stock options or common stock purchased under the ESPP. Management will continue to assess the assumptions and methodologies used to calculate the estimated fair value of stock-based compensation. Circumstances may change and additional data may become available over time, which could result in changes to these assumptions and methodologies, and which could materially impact our fair value determination.

We expense the value of the portion of the option or award that is ultimately expected to vest based on the historical forfeiture rate on a straight line basis over the requisite service periods in our Consolidated Statements of Operations. For awards that vest upon the achievement of performance milestones, we estimate the vesting period based on our evaluation of the probability of achievement of each respective milestone and the related estimated date of achievement. Stock-based compensation expense for purchases under the ESPP is recognized over the respective six-month purchase period. Expense amounts are allocated among inventory, cost of goods sold, research and development expense, and general and administrative expense based on the function of the applicable employee. Stock-based compensation charges are non-cash charges and as such have no impact on our reported cash flows.

Research and Development Expense

Research and development costs are expensed as incurred and include salaries, benefits and other operating costs such as outside services, supplies and allocated overhead costs. We perform research and development for our proprietary drug candidates and technology development and for certain third parties under collaboration agreements. For our proprietary drug candidates and our internal technology development programs, we invest our own funds without reimbursement from a third party.

We record accruals for the estimated costs of our clinical trial activities performed by third parties. We generally accrue costs associated with the start-up and reporting phases of the clinical trials ratably over the estimated duration of the start-up and reporting phases. We generally accrue costs associated with the treatment phase of clinical trials based on the total estimated cost of the treatment phase on a per patient basis and we expense the per patient cost ratably over the estimated patient treatment period based on patient enrollment in the trials. In specific circumstances, such as for certain time-based costs, we recognize clinical trial expenses using a methodology that we consider to be more reflective of the timing of costs incurred. Advance payments for goods or services that will be used or rendered for future research and development activities are capitalized as prepaid expenses and recognized as expense as the related goods are delivered or the related services are performed.

Net Loss Per Share

Basic net loss per share is calculated based on the weighted-average number of common shares outstanding during the periods presented. For all periods presented in the Consolidated Statements of Operations, the net loss available to common stockholders is equal to the reported net loss. Basic and diluted net loss per share are the same due to our historical net losses and the requirement to exclude potentially dilutive securities which would have an anti-dilutive effect on net loss per share. The weighted average of these potentially dilutive securities has been excluded from the diluted net loss per share calculation and is as follows (in thousands):


	Year Ended December 31,
	2013		2012		2011
Stock options		12,959		13,970		11,338
Convertible subordinated notes		—		—		9,989

Total		12,959		13,970		21,327

Income Taxes

We account for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and tax reporting bases of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Realization of deferred tax assets is dependent upon future earnings, the timing and amount of which are uncertain. We record a valuation allowance against deferred tax assets to reduce their carrying value to an amount that is more likely than not to be realized. When we establish or reduce the valuation allowance related to the deferred tax assets, our provision for income taxes will increase or decrease, respectively, in the period such determination is made.

We utilize a two-step approach to recognize and measure uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained upon tax authority examination, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement.

Comprehensive loss

Comprehensive loss is the change in stockholders’ equity (deficit) from transactions and other events and circumstances other than those resulting from investments by stockholders and distributions to stockholders. Our other comprehensive income (loss) is comprised of net loss, gains and losses from the foreign currency translation of the assets and liabilities of our India and UK subsidiaries, and unrealized gains and losses on investments in available-for-sale securities.

Recent Accounting Pronouncements

In July 2013, the Financial Accounting Standards Board issued a new accounting standard that will require the presentation of certain unrecognized tax benefits as a reduction to deferred tax assets rather than as a liability when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. This guidance is effective for our interim and annual periods beginning January 1, 2014. We do not believe the adoption of this guidance will have a material impact on our consolidated financial statements.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=28200181&loc=SL6228881-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 15

-URI http://asc.fasb.org/subtopic&trid=2122524

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6359566&loc=d3e326-107755

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=7668296&loc=d3e288-107754

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2197480

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=18733093&loc=d3e5614-111684

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 915

-SubTopic 235

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6472506&loc=d3e38932-110933

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2209116

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2134480

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2122150

+ Details

Cash and Investments in Marketable Securities

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Cash and Investments in Marketable Securities

Note 2 — Cash and Investments in Marketable Securities

Cash and investments in marketable securities, including cash equivalents and restricted cash, are as follows (in thousands):


	Estimated Fair Value at
	December 31, 2013		December 31, 2012
Cash and cash equivalents	$	39,067	$	25,437
Short-term investments		197,959		251,757
Restricted cash		25,000		25,000

Total cash and investments in marketable securities	$	262,026	$	302,194

We invest in liquid, high quality debt securities. Our investments in debt securities are subject to interest rate risk. To minimize the exposure due to an adverse shift in interest rates, we invest in securities with maturities of two years or less and maintain a weighted average maturity of one year or less. As of December 31, 2013 and 2012, all of our investments had contractual maturities of one year or less and were classified as short-term.

Gross unrealized gains and losses were not significant at either December 31, 2013 or 2012. During the years ended December 31, 2013, 2012 and 2011, we sold available-for-sale securities totaling $2.9 million, $5.4 million and $210.1 million respectively, and realized gains and losses were not significant in any of those periods.

Restricted cash of $25.0 million is required to be maintained in a separate account until July 1, 2015 under the terms of our 12% Senior Secured Notes due July 2017 (see Note 5).

Our portfolio of cash and investments in marketable securities includes (in thousands):


	Fair Value Hierarchy Level		Estimated Fair Value at
	Fair Value Hierarchy Level		December 31, 2013		December 31, 2012
Corporate notes and bonds		2	$	138,515	$	241,158
U.S. corporate commercial paper		2		59,444		3,990
Obligations of U.S. government agencies		2		—		6,108
Obligations of U.S. states and municipalities		2		—		1,504

Available-for-sale investments				197,959		252,760
Money market funds		1		26,453		22,487
Cash, including restricted cash		N/A		37,614		26,947

Total cash and investments in marketable securities			$	262,026	$	302,194

Level 1 — Quoted prices in active markets for identical assets or liabilities.

Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

All of our investments are categorized as Level 1 or Level 2, as explained in the table above. We use a market approach to value our Level 2 investments. During the years ended December 31, 2013 and 2012, there were no transfers between Level 1 and Level 2 of the fair value hierarchy.

At December 31, 2013 and 2012, we had letter of credit arrangements in favor of a landlord and certain vendors totaling $2.4 million. These letters of credit are secured by investments of similar amounts.

- 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

Inventory

12 Months Ended

Dec. 31, 2013

Inventory Disclosure [Abstract]

Inventory

Note 3 — Inventory

Inventory consists of the following (in thousands):


	December 31,
	2013		2012
Raw materials	$	3,947	$	7,489
Work-in-process		6,146		6,661
Finished goods		3,359		4,119

Inventory	$	13,452	$	18,269

- Definition

The entire disclosure for inventory. This may include, but is not limited to, the basis of stating inventory, the method of determining inventory cost, the major classes of inventory, and the nature of the cost elements included in inventory. If inventory is stated above cost, accrued net losses on firm purchase commitments for inventory and losses resulting from valuing inventory at the lower-of-cost-or-market may also be included. For LIFO inventory, may disclose the amount and basis for determining the excess of replacement or current cost over stated LIFO value and the effects of a LIFO quantities liquidation that impacts net income.

+ References+ Details

Property and Equipment

12 Months Ended

Dec. 31, 2013

Property Plant And Equipment [Abstract]

Property and Equipment

Note 4 — Property and Equipment

Property and equipment consist of the following (in thousands):


	December 31,
	2013			2012
Building and leasehold improvements	$	71,306		$	72,180
Laboratory equipment		26,621			27,145
Manufacturing equipment		23,699			20,877
Furniture, fixtures and other equipment		23,235			21,914

Depreciable property and equipment at cost		144,861			142,116
Less: accumulated depreciation		(84,148	)		(72,666	)

Depreciable property and equipment, net		60,713			69,450
Construction-in-progress		6,261			2,765

Property and equipment, net	$	66,974		$	72,215

Building and leasehold improvements include our manufacturing, research and development and administrative facilities and the related improvements to these facilities. Laboratory and manufacturing equipment include assets that support both our manufacturing and research and development efforts. Construction-in-progress includes assets being built to enhance our manufacturing and research and development efforts. Property and equipment includes certain assets acquired through capital leases (see Note 6).

In July 2012, we consolidated our U.S.-based research activities into our existing San Francisco facility and ceased use of and plan to sell one of our buildings located in Huntsville, Alabama that was dedicated to research activities. The announcement of this consolidation plan in March 2012 triggered the recognition of a $1.7 million impairment charge relating to these assets in the year ended December 31, 2012.

Depreciation expense, including depreciation of assets acquired through capital leases, for the years ended December 31, 2013, 2012, and 2011 was $13.0 million, $13.8 million, and $15.0 million, respectively.

- Definition

The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures.

+ References+ Details

Senior Secured Notes	12 Months Ended
Senior Secured Notes	Dec. 31, 2013
Debt Disclosure [Abstract]
Senior Secured Notes	Note 5 — Senior Secured Notes On July 11, 2012, we issued $125.0 million in aggregate principal amount of senior secured notes (Senior Notes) with the entire principal amount due on July 15, 2017. The Senior Notes bear interest at 12.0% per annum payable in cash semi-annually in arrears on January 15 and July 15 of each year, beginning January 15, 2013. The Senior Notes are secured by a first-priority lien on substantially all of our assets. In connection with this transaction, we retired $42.5 million of principal amount of our convertible subordinated notes due September 2012 in exchange for the same principal amount of Senior Notes and received the remaining proceeds in cash, less approximately $4.5 million in transaction costs. We used the proceeds from the issuance of the Senior Notes and our existing cash to repay the remaining $172.4 million in principal amount of our convertible subordinated notes in full at maturity on September 28, 2012. The Senior Notes contain customary covenants, including covenants that limit or restrict our ability to incur liens, incur indebtedness, and make certain restricted payments, but do not contain covenants related to future financial performance. In particular, $25.0 million of the proceeds is required to be maintained in a restricted account until July 1, 2015 and is classified as restricted cash on our Consolidated Balance Sheets. From July 1, 2015 through the quarter ending June 30, 2017, the aggregate balance of our unrestricted cash and cash equivalents at the end of any two consecutive fiscal quarters is required to be at least $25.0 million, subject to certain conditions. The Senior Notes are callable by us at any time, subject to certain prepayment premiums and conditions. If we experience certain change of control events, the holders of the Senior Notes will have the right to require us to purchase all or a portion of the Senior Notes at a purchase price in cash equal to 101% of the principal amount thereof, plus accrued and unpaid interest to the date of purchase. In addition, upon certain asset sales, we may be required to offer to use the net proceeds thereof to purchase some of the Senior Notes at 100% of the principal amount thereof, plus accrued and unpaid interest to the date of purchase. As of December 31, 2013, based on a discounted cash flow analysis using Level 3 inputs including financial discount rates, we believe the $125.0 million carrying amount of our 12% Senior Secured Notes due July 2017 is consistent with its fair value.

Leases

12 Months Ended

Dec. 31, 2013

Text Block [Abstract]

Leases

Note 6 — Leases

Capital Leases

We lease office space at 201 Industrial Road in San Carlos, California under a capital lease arrangement. Under the terms of the lease, rent increases up to 3% annually and the lease termination date is October 5, 2016. As of November 29, 2010, we ceased use of this space as a result of the relocation of our San Carlos operations and corporate headquarters to San Francisco, California. As a result of our relocation, an impairment test was performed for the building and related leasehold improvements located in San Carlos. As a result of this impairment test, we recorded an impairment charge of $12.6 million in 2010. As of December 31, 2013 and 2012, the gross amount of assets recorded under capital leases was $2.3 million and the recorded value of these assets, net of depreciation, was $1.0 million and $1.4 million, respectively.

We have subleased all of the San Carlos facility, but have not been relieved of any obligations under the terms of this lease. Our future minimum rental receipts under the San Carlos facility subleases total $7.4 million as of December 31, 2013.

Future minimum payments for our capital leases at December 31, 2013 are as follows (in thousands):


Years ending December 31,
2014	$	5,169
2015		5,280
2016		4,034

Total minimum payments required		14,483
Less: amount representing interest		(2,898	)

Present value of future minimum lease payments		11,585
Less: current portion		(3,536	)

Capital lease obligation, less current portion	$	8,049

Operating Lease

On September 30, 2009, we entered into an operating sublease (Sublease) with Pfizer, Inc. for a 102,283 square foot facility located in San Francisco, California (Mission Bay Facility). Upon completion of construction of the Mission Bay Facility, we moved in on November 29, 2010. The Mission Bay Facility includes a research and development center with biology, chemistry, pharmacology, and clinical development capabilities, as well as all of the functions previously located in San Carlos, California, including our corporate headquarters.

Under the terms of the Sublease, we will begin making non-cancelable lease payments in 2014, after the expiration of our free rent period on August 1, 2014. The Sublease term is 114 months, commencing in August 2010 and terminating on January 31, 2020. Monthly base rent will escalate over the term of the sublease at various intervals. In addition, throughout the term of the Sublease, we are responsible for paying certain costs and expenses specified in the Sublease, including insurance costs and a pro rata share of operating expenses and applicable taxes for the Mission Bay Facility.

On December 28, 2011, we expanded our lease of the Mission Bay Facility to include an additional 24,002 square feet of space. The lease term commenced on December 28, 2011 and ends on January 31, 2020. Monthly base rent will escalate over the term of the lease at various intervals.

Our future minimum lease payments for our operating leases at December 31, 2013 are as follows (in thousands):


Years ending December 31,
2014	$	2,559
2015		4,750
2016		4,892
2017		5,037
2018		5,187
2019 and thereafter		5,796

Total future minimum lease payments	$	28,221

We recognize rent expense on a straight-line basis over the lease period. For the years ended December 31, 2013, 2012, and 2011, rent expense for all our operating leases, including our Mission Bay Facility, was approximately $2.9 million, $2.8 million, and $2.4 million, respectively.

Liability Related to Sale of Future Royalties

12 Months Ended

Dec. 31, 2013

Text Block [Abstract]

Note 7 — Liability Related to Sale of Future Royalties

On February 24, 2012, we entered into a Purchase and Sale Agreement (the Purchase and Sale Agreement) with RPI Finance Trust (RPI), an affiliate of Royalty Pharma, pursuant to which we sold, and RPI purchased, our right to receive royalty payments (the Royalty Entitlement) arising from the worldwide net sales, from and after January 1, 2012, of (a) CIMZIA^®, under Nektar’s license, manufacturing and supply agreement with UCB Pharma (UCB), and (b) MIRCERA^®, under Nektar’s license, manufacturing and supply agreement with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (together referred to as Roche). We received aggregate cash proceeds for the Royalty Entitlement of $124.0 million. As part of this sale, we incurred approximately $4.4 million in transaction costs, which will be amortized to interest expense over the estimated life of the Purchase and Sale Agreement. Although we sold all of our rights to receive royalties from the CIMZIA^® and MIRCERA^® products, as a result of our ongoing manufacturing and supply obligations related to the generation of these royalties, we will continue to account for these royalties as revenue and recorded the $124.0 million in proceeds from this transaction as a liability (Royalty Obligation) that will be amortized using the interest method over the estimated life of the Purchase and Sale Agreement.

The following table shows the activity within the liability account during the year ended December 31, 2013 and for the period from the inception of the royalty transaction on February 24, 2012 (inception) to December 31, 2013 (in thousands):


	Year ended December 31, 2013			Period from inception to December 31, 2013
Liability related to sale of future royalties—beginning balance	$	131,266		$	—
Proceeds from sale of future royalties		—			124,000
Non-cash interest expense recognized		22,309			40,366
Non-cash CIMZIA^® and MIRCERA^® royalty revenue		(22,055	)		(32,846	)
Payments from Nektar to RPI		(3,000	)		(3,000	)

Total liability related to sale of future royalties as of December 31, 2013		128,520			128,520
Less: current portion		(7,000	)		(7,000	)

Liability related to sale of future royalties, less current portion	$	121,520		$	121,520

As a result of this liability accounting, even though the royalties from UCB and Roche are remitted directly to RPI starting with royalties arising from product sales in the first quarter of 2012, we will continue to recognize revenue for these royalties. During the year ended December 31, 2012, we recognized royalties from net sales of CIMZIA^® and MIRCERA^® upon notification of the actual royalty amount, which occurs in the quarter after such sales are made. During the year ended December 31, 2013, we began to recognize royalties based on estimates of the net sales made in each period, which resulted in an increase in non-cash royalty revenue of $4.6 million in the year ended December 31, 2013. During the years ended December 31, 2013 and 2012, we recognized $22.1 and $10.8 million, respectively, in non-cash royalties from net sales of CIMZIA^® and MIRCERA^®.

As royalties are remitted to RPI from Roche and UCB, the balance of the Royalty Obligation will be effectively repaid over the life of the agreement. In order to determine the amortization of the Royalty Obligation, we are required to estimate the total amount of future royalty payments to be received by RPI and payments we are required to make to RPI as noted below, if any, over the life of the agreement. The sum of these amounts less the $124.0 million proceeds we received will be recorded as interest expense over the life of the Royalty Obligation. Since inception, our estimate of this total interest expense resulted in an effective annual interest rate of approximately 17%. We periodically assess the estimated royalty payments to RPI from UCB and Roche and to the extent such payments are greater or less than our initial estimates, or the timing of such payments is materially different than our original estimates, we will prospectively adjust the amortization of the Royalty Obligation. There are a number of factors that could materially affect the amount and timing of royalty payments from CIMZIA^® and MIRCERA^®, most of which are not within our control. Such factors include, but are not limited to, changing standards of care, the introduction of competing products, manufacturing or other delays, biosimilar competition, intellectual property matters, adverse events that result in governmental health authority imposed restrictions on the use of the drug products, and other events or circumstances that could result in reduced royalty payments from CIMZIA^® and MIRCERA^®, all of which would result in a reduction of non-cash royalty revenues and the non-cash interest expense over the life of the Royalty Obligation. Conversely, if sales of CIMZIA^® and MIRCERA^® are more than expected, the non-cash royalty revenues and the non-cash interest expense recorded by us would be greater over the term of the Royalty Obligation.

Pursuant to the Purchase and Sale Agreement, in March 2013, we were required to pay RPI $3.0 million because worldwide net sales of MIRCERA^® for the 12 month period ended December 31, 2012 did not reach a required threshold. Furthermore, we are required to make an additional payment of up to $7.0 million if the specified worldwide net sales threshold of MIRCERA^® for the 12 month period ended December 31, 2013 is not achieved. We have concluded that it is probable that the minimum 2013 MIRCERA^® net sales threshold will not be met and, therefore, we expect to make the $7.0 million payment to RPI described above in early 2014. The liability for this expected $7.0 million payment is included in current liabilities on our Consolidated Balance Sheet at December 31, 2013.

In addition, the Purchase and Sale Agreement grants RPI the right to receive certain reports and other information relating to the Royalty Entitlement and contains other representations and warranties, covenants and indemnification obligations that are customary for a transaction of this nature. In particular, if we breach our obligations under the Purchase and Sale Agreement, we could be required to pay damages to RPI that are not limited to the purchase price we received in the sale transaction.

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 8 — Commitments and Contingencies *Royalty Expense* We have third party licenses that require us to pay royalties based on our sales of certain products and/or on our recognition of royalty revenue under certain of our collaboration agreements. Royalty expense, which is reflected in cost of goods sold in our Consolidated Statements of Operations, was approximately $4.1 million, $2.9 million, and $1.8 million for the years ended December 31, 2013, 2012, and 2011, respectively. The overall maximum amount of these obligations is based upon sales of the applicable products by our collaboration partners and cannot be reasonably estimated. *Purchase Commitments* In the normal course of business, we enter into various firm purchase commitments related to contract manufacturing, clinical development and certain other items. As of December 31, 2013, these commitments were approximately $12.6 million, all of which are expected to be paid in 2014. *Legal Matters* From time to time, we are involved in lawsuits, arbitrations, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters, which arise in the ordinary course of business. We make provisions for liabilities when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Such provisions are reviewed at least quarterly and adjusted to reflect the impact of settlement negotiations, judicial and administrative rulings, advice of legal counsel, and other information and events pertaining to a particular case. Litigation is inherently unpredictable. If any unfavorable ruling were to occur in any specific period, there exists the possibility of a material adverse impact on the results of operations of that period or on our cash flows and liquidity. On November 18, 2009, the Research Foundation of the State University of New York (SUNY) filed an action against us in the United States District Court for the Northern District of New York. SUNY sought to recover amounts it alleged it was owed pursuant to a technology licensing contract between us and SUNY. On December 20, 2013, we entered into a Settlement Agreement and Release (Settlement) with SUNY. Under the terms of the Settlement, SUNY agreed to dismiss the action with prejudice and relinquish all rights it may have had to a portion of future development and regulatory milestone payments payable to us under the Co-Development, License and Co-Promotion Agreement, dated August 1, 2007, between us (and our subsidiaries) and Bayer Healthcare LLC, as amended, related to the inhaled amikacin program in exchange for (i) a $5.0 million payment due on April 1, 2014; (ii) a $5.0 million payment due on January 1, 2015, (iii) a series of four $500,000 payments each due on April 1, 2014, January 1, 2015, January 1, 2016, and January 1, 2017, respectively; and (iv) certain other terms and conditions. As a result of the Settlement, we recorded a charge of $11.3 million to research and development expense during the year ended December 31, 2013 which reflects the estimated net present value of the $12.0 million settlement payments using an 8% annual discount rate. As of December 31, 2013, the $5.5 million current portion of the $11.3 million settlement liability is included in other current liabilities in our Consolidated Balance Sheet. *Indemnification Obligations* During the course of our normal operating activities, we have agreed to certain contingent indemnification obligations as further described below. The term of our indemnification obligations is generally perpetual. There is generally no limitation on the potential amount of future payments we could be required to make under these indemnification obligations. To date, we have not incurred significant costs to defend lawsuits or settle claims based on our indemnification obligations. If any of our indemnification obligations is triggered, we may incur substantial liabilities. Because the aggregate amount of any potential indemnification obligation is not a stated amount, the overall maximum amount of any such obligations cannot be reasonably estimated. No liabilities have been recorded for these obligations on our Consolidated Balance Sheets as of December 31, 2013 or 2012. *Indemnifications in Connection with Commercial Agreements* As part of our collaboration agreements with our partners related to the license, development, manufacture and supply of drugs based on our proprietary technologies and drug candidates, we generally agree to defend, indemnify and hold harmless our partners from and against third party liabilities arising out of the agreement, including product liability (with respect to our activities) and infringement of intellectual property to the extent the intellectual property is developed by us and licensed to our partners. As part of the sale of our royalty interest in the CIMZIA^® and MIRCERA^® products, we and RPI made representations and warranties and entered into certain covenants and ancillary agreements which are supported by indemnity obligations. Additionally, as part of our pulmonary asset sale to Novartis in 2008, we and Novartis made representations and warranties and entered into certain covenants and ancillary agreements which are supported by an indemnity obligation. In the event it is determined that we breached certain of the representations and warranties or covenants and agreements made by us in any such agreements, we could incur substantial indemnification liabilities depending on the timing, nature, and amount of any such claims. *Indemnification of Underwriters and Initial Purchasers of our Securities* In connection with our sale of equity and senior secured debt securities, we have agreed to defend, indemnify and hold harmless our underwriters or initial purchasers, as applicable, as well as certain related parties from and against certain liabilities, including liabilities under the Securities Act of 1933, as amended. *Director and Officer Indemnifications* As permitted under Delaware law, and as set forth in our Certificate of Incorporation and our Bylaws, we indemnify our directors, executive officers, other officers, employees, and other agents for certain events or occurrences that may arise while in such capacity. The maximum potential amount of future payments we could be required to make under this indemnification is unlimited; however, we have insurance policies that may limit our exposure and may enable us to recover a portion of any future amounts paid. Assuming the applicability of coverage, the willingness of the insurer to assume coverage, and subject to certain retention, loss limits and other policy provisions, we believe any obligations under this indemnification would not be material, other than an initial $1,000,000 per incident for securities related claims and $500,000 per incident for non-securities related claims retention deductible per our insurance policy. However, no assurances can be given that the covering insurers will not attempt to dispute the validity, applicability, or amount of coverage without expensive litigation against these insurers, in which case we may incur substantial liabilities as a result of these indemnification obligations.

- Definition

The entire disclosure for commitments and contingencies.

+ References+ Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Stockholders' Equity

Note 9 — Stockholders’ Equity

Preferred Stock

We have authorized 10,000,000 shares of Preferred Stock with each share having a par value of $0.0001. In 2011, 3,100,000 shares were previously designated Series A Junior Participating Preferred Stock (Series A Preferred Stock) in connection with our Share Purchase Rights Plan (Rights Plan) that expired on June 1, 2011. On March 30, 2012, we filed a certificate of elimination of the Series A Preferred Stock. As of December 31, 2013 and 2012, no preferred shares are designated, issued or outstanding.

Common Stock

On January 24, 2011, we completed the issuance and sale of 19,000,000 shares of our common stock for gross proceeds to the Company of approximately $220.4 million. Additionally, we incurred approximately $0.6 million in legal and accounting fees, filing fees, and other offering expenses.

On January 28, 2014, we completed the issuance and sale of 9,775,000 shares of our common stock for gross proceeds to the Company of approximately $117.2 million. Additionally, we incurred approximately $0.6 million in legal and accounting fees, filing fees, and other offering expenses.

Equity Compensation Plans

At December 31, 2013, we had 28,609,480 reserved shares of common stock, all of which are reserved for issuance under our equity compensation plans as summarized in the following table (share number in thousands):


Plan Category	Number of Securities to be Issued Upon Exercise of Outstanding Options (a)		Weighted-Average Exercise Price of Outstanding Options (b)		Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column(a)) (c)
Equity compensation plans approved by security holders(1)		14,936	$	8.76		7,954
Equity compensation plans not approved by security holders		5,719	$	9.84		—

Total		20,655	$	9.06		7,954

(1)	Includes shares of common stock available for future issuance under our ESPP as of December 31, 2013.

2012 Performance Incentive Plan

Our 2012 Performance Incentive Plan (2012 Plan) was adopted by the Board of Directors on April 4, 2012 and was approved by our stockholders on June 28, 2012. On the date of approval, any shares of our common stock that were available for issuance under all other previously existing stock plans (the 2008 Equity Incentive Plan, the 2000 Equity Incentive Plan, and the 2000 Non-Officer Equity Incentive Plan) became available for issuance under the 2012 Plan. In addition, 5,300,000 new shares were made available for award grants under the 2012 Plan. No new awards were granted under any of the previous stock plans after June 28, 2012. Any shares of common stock subject to outstanding awards under the previous stock plans that expire, are cancelled, or otherwise terminate at any time after December 31, 2011 are also available for award grant purposes under the 2012 Plan.

The purpose of the 2012 Plan and our other incentive plans is to attract, motivate, retain, and reward directors, officers, employees, and other eligible persons through the grant of awards and incentives for high levels of individual performance and increasing the value of our business, as well as to further align the interests of award recipients and our stockholders. The 2012 Plan authorizes stock options, stock appreciation rights, restricted stock, performance stock, stock units, stock bonuses, dividend equivalents, other similar rights to purchase or acquire shares, and other forms of awards granted or denominated in our common stock or units of the company’s common stock, as well as cash bonus awards. Directors, officers, or employees, and certain consultants and advisors may receive awards under the 2012 Plan. In 2012 and 2013, the requisite service period for stock options granted to our employees under the 2012 Plan as well as all other previously existing stock plans was generally four years; the requisite service period for stock options granted to our directors was generally one year.

The maximum number of shares of our common stock that may be issued or transferred pursuant to awards under the 2012 Plan is 10,347,140 shares, plus any shares subject to outstanding awards under the previous stock plans that expire, are cancelled, or otherwise terminate for any reason. Generally, shares that are subject to or underlie awards which expire or for any reason are cancelled or terminated, are forfeited, fail to vest, or for any other reason (except for shares exchanged by a participant or withheld to pay the exercise price of an award granted and related tax withholding obligations) are not paid or delivered under the 2012 Plan will again be available for subsequent awards under the 2012 Plan. Shares issued in respect of any award, other than a stock option or stock appreciation right, granted under the 2012 Plan will be counted against the plan’s share limit as 1.5 shares for every one share actually issued in connection with the award.

The 2012 Plan will terminate on April 3, 2022, unless earlier terminated by the Board of Directors. The maximum term of a stock option or stock appreciation right under the 2012 Plan is eight years from the date of grant. The per share exercise price of an option generally may not be less than the fair market value of a share of the company’s common stock on the Nasdaq Global Select Market on the date of grant.

Other Equity Incentive Plans

In addition to the 2012 Plan, we have other equity incentive plans under which options granted remain outstanding but no new options may be granted either as a result of the approval of the 2012 Plan or plan expiration. These plans include: (i) the 2008 Equity Incentive Plan (2008 Plan) which was adopted by the Board of Directors on March 20, 2008 and approved by our stockholders on June 6, 2008; (ii) the 2000 Equity Incentive Plan (2000 Plan) which was adopted by the Board of Directors on April 19, 2000 by amending and restating our 1994 Equity Incentive Plan, and which expired on February 9, 2010; and (iii) the 1998 Non-Officer Equity Incentive Plan which was adopted by our Board of Directors on August 18, 1998, and which was amended and restated in its entirety and renamed the 2000 Non-Officer Equity Incentive Plan on June 6, 2000 (2000 Non-Officer Plan).

Pursuant to the 2008 Plan and the 2000 Plan, we previously granted or issued incentive stock options to employees and officers and non-qualified stock options, rights to acquire restricted stock, restricted stock units, and stock bonuses to employees, officers, non-employee directors, and consultants. Pursuant to the 2000 Non-Officer Plan, we previously granted or issued non-qualified stock options, rights to acquire restricted stock and stock bonuses to employees and consultants who are neither officers nor directors of Nektar. The maximum term of a stock option under all of these plans is eight years.

Restricted Stock Units

RSU awards have been granted under the 2008 Plan, the 2000 Plan and the 2000 Non-Officer Plan and are settled by delivery of shares of our common stock on or shortly after the date the awards vest. We did not grant any RSU awards during the years ended December 31, 2013, 2012 or 2011 and no RSUs are outstanding at December 31, 2013. RSU awards are similar to restricted stock in that they are issued for no consideration; however, the holder generally is not entitled to the underlying shares of common stock until the RSU award vests. Also, because the RSU awards are granted for $0.01 per share, the grant-date fair value of the award is equal to the intrinsic value of our common stock on the date of grant.

Beginning with shares granted during 2005, each RSU award depletes the pool of options available for grant under our equity incentive plans by a ratio of 1:1.5.

Employee Stock Purchase Plan

In February 1994, our Board of Directors adopted the Employee Stock Purchase Plan (ESPP) pursuant to section 423(b) of the Internal Revenue Code of 1986. Under the ESPP, 1,500,000 shares of our common stock have been authorized for issuance. The terms of the ESPP provide eligible employees with the opportunity to acquire an ownership interest in Nektar through participation in a program of periodic payroll deductions for the purchase of our common stock. Employees may elect to enroll or re-enroll in the ESPP on a semi-annual basis. Stock is purchased at 85% of the lower of the closing price on the first day of the enrollment period or the last day of the enrollment period.

401(k) Retirement Plan

We sponsor a 401(k) retirement plan whereby eligible employees may elect to contribute up to the lesser of 60% of their annual compensation or the statutorily prescribed annual limit allowable under Internal Revenue Service regulations. The 401(k) plan permits us to make matching contributions on behalf of all participants, up to a maximum of $3,000 per participant. For the years ended December 31, 2013, 2012, and 2011, we recognized $1.0 million, $0.9 million, and $0.9 million, respectively, of compensation expense in connection with our 401(k) retirement plan.

Change in Control Severance Plan

On December 6, 2006, our Board of Directors approved a Change of Control Severance Benefit Plan (CIC Plan). This CIC Plan has subsequently been amended a number of times by our Board of Directors with the most recent amendment occurring on April 5, 2011. The CIC Plan is designed to make certain benefits available to our eligible employees in the event of a change of control of Nektar and, following such change of control, an employee’s employment with us or a successor company is terminated in certain specified circumstances. We adopted the CIC Plan to support the continuity of the business in the context of a change of control transaction. The CIC Plan was not adopted in contemplation of any specific change of control transaction.

Under the CIC Plan, in the event of a change of control of Nektar and a subsequent termination of employment initiated by us or a successor company other than for Cause (as defined in the CIC Plan) or initiated by the employee for a Good Reason Resignation (as defined in the CIC Plan) in each case within twelve months following a change of control transaction, (i) the Chief Executive Officer would be entitled to receive cash severance pay equal to 24 months base salary plus annual target incentive pay, the extension of employee benefits over this severance period and the full acceleration of unvested outstanding equity awards, and (ii) our Senior Vice Presidents and Vice Presidents (including Principal Fellows) would each be entitled to receive cash severance pay equal to twelve months base salary plus annual target incentive pay, the extension of employee benefits over this severance period and the full acceleration of unvested outstanding equity awards. In the event of a change of control of Nektar and a subsequent termination of employment initiated by the Company or a successor company other than for Cause within twelve months following a change of control transaction, all other employees would each be entitled to receive cash severance pay equal to 6 months base salary plus a pro-rata portion of annual target incentive pay, the extension of employee benefits over this severance period and the full acceleration of each such employee’s unvested outstanding equity awards. Under the CIC Plan, as amended, non-employee directors would also be entitled to full acceleration of vesting of all outstanding stock awards in the event of a change of control transaction.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ 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 210.5-02.29-31)

-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 6

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 4.E)

-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 4

-Subparagraph (SAB TOPIC 4.C)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section C

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section E

Reference 9: 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.(d),(e))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Preferred Stock

-URI http://asc.fasb.org/extlink&oid=6521494

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 14: 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 15: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 17: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 18: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph d

-Article 4

Reference 19: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

+ Details

License and Collaboration Agreements

12 Months Ended

Dec. 31, 2013

Organization Consolidation And Presentation Of Financial Statements [Abstract]

License and Collaboration Agreements

Note 10 — License and Collaboration Agreements

We have entered into various collaboration agreements including license agreements and collaborative research, development and commercialization agreements with various pharmaceutical and biotechnology companies. Under these collaboration arrangements, we are entitled to receive license fees, upfront payments, milestone payments, royalties, sales milestones, and payments for the manufacture and supply of our proprietary PEGylation materials and/or reimbursement for research and development activities. All of our collaboration agreements are generally cancelable by our partners without significant financial penalty. Our costs of performing these services are generally included in research and development expense, except that costs for product sales to our collaboration partners are included in cost of goods sold.

In accordance with our collaboration agreements, we recognized license, collaboration and other revenue as follows (in thousands):


		Year Ended December 31,
Partner	Agreement	2013		2012		2011
AstraZeneca AB	Naloxegol (NKTR-118) and naloxegol fixed-dose combination program (NKTR-119)	$	25,016	$	59	$	2,496
Roche	PEGASYS^® and MIRCERA^®		18,382		7,146		5,131
Bayer Healthcare LLC	BAY41-6551 (Amikacin Inhale)		15,293		2,971		2,992
Affymax, Inc.	OMONTYS^®		7,149		2,829		3,838
Amgen, Inc.	Neulasta^®		5,035		5,000		5,000
Baxter Healthcare	BAX 855 (Hemophilia)		1,702		6,238		5,646
Other			8,295		5,884		11,186

License, collaboration and other revenue		$	80,872	$	30,127	$	36,289

As of December 31, 2013, our collaboration agreements with partners included potential future payments for development milestones totaling approximately $144.3 million, including amounts from our agreements with Baxter and Bayer described below. In addition, we are entitled to receive up to $175.0 million and $75.0 million of contingent payments related to NKTR-118 and NKTR-119, respectively, based on development and regulatory events to be pursued and completed solely by AstraZeneca.

AstraZeneca AB: naloxegol (NKTR-118) and naloxegol fixed-dose combination program (NKTR-119)

In September 2009, we entered into a license agreement with AstraZeneca AB (AstraZeneca), as amended by AstraZeneca and us in August 2013, under which we granted AstraZeneca a worldwide, exclusive, perpetual, royalty-bearing, and sublicensable license under our patents and other intellectual property to develop, market, and sell naloxegol (formerly known as NKTR-118) and naloxegol fixed-dose combination program (formerly known as NKTR-119). AstraZeneca is responsible for all costs associated with research, development and commercialization and is responsible for all drug development and commercialization decisions for naloxegol and the naloxegol fixed-dose combination program. AstraZeneca paid us an upfront payment of $125.0 million, which we received in the fourth quarter of 2009 and which was fully recognized as of December 31, 2010. As of December 31, 2013, we are entitled to receive up to an additional $175.0 million and $75.0 million of contingent payments related to naloxegol and the naloxegol fixed-dose combination program, respectively, based on development events to be pursued and completed solely by AstraZeneca, as described below.

On September 25, 2013, the European Medicines Agency (EMA) notified AstraZeneca that it had accepted for review the naloxegol regulatory approval application filed by AstraZeneca in August 2013. As a result, we were entitled to a $25.0 million payment from AstraZeneca, which was received on September 30, 2013 and was fully recognized as revenue in the year ended December 31, 2013.

On September 16, 2013, AstraZeneca filed a New Drug Application (NDA) with the United States Food and Drug Administration (FDA) for naloxegol, which was accepted for review by the FDA on November 16, 2013, resulting in a $70.0 million milestone payment to us from AstraZeneca in November 2013. We cannot recognize revenue for this payment until it is no longer refundable and, as a result of the potential for repayment of the $70.0 million (as described below), we have recorded this amount in the line item “Liability related to receipt of refundable milestone payment” on our Consolidated Balance Sheet at December 31, 2013. If the FDA does not require a future clinical trial or other significant studies to assess the cardiovascular safety (CV Safety Study) of naloxegol prior to an approval decision, AstraZeneca is obligated to pay us an additional $35.0 million. If the FDA does require a CV Safety Study, AstraZeneca may terminate the license agreement with us in its entirety or only with respect to its rights in the United States. If AstraZeneca elects to terminate the license agreement in its entirety due to a CV Safety Study, we would be required to repay them the $70.0 million payment plus accrued interest at 4.5% compounded annually in four installments in accordance with the following payment schedule: $10.0 million plus accrued interest on January 15, 2015, $10.0 million plus accrued interest on January 15, 2016, $20.0 million plus accrued interest on January 15, 2017 and $30.0 million plus accrued interest on January 15, 2018. If AstraZeneca elects to terminate the license agreement only with respect to its rights in the U.S., then such repayment amount would be funded through a 50% reduction of non-U.S. royalty amounts otherwise payable to us until the aggregate amount of such royalty reduction equals the total principal amount of $70.0 million plus accumulated interest at 4.5% compounded annually. If the FDA requires a post-approval cardiovascular safety study as a condition to approval of the naloxegol NDA, then the royalty rate payable to us from net sales of naloxegol in the U.S. by AstraZeneca would be reduced by two percentage points until the aggregate accumulated amount of such royalty payment reduction is equal to a maximum of $35.0 million.

We will be entitled to the remaining $140.0 million of contingent payments if naloxegol is approved by the FDA and EMA and commercial launch is achieved in the U.S. and one major country in the European Union. In addition, we are also entitled to sales milestone payments and royalties based on annual worldwide net sales of naloxegol and naloxegol fixed-dose combination products.

Roche : PEGASYS^® and MIRCERA^®

In February 1997, we entered into a license, manufacturing and supply agreement with Roche, under which we granted Roche a worldwide, exclusive license to certain intellectual property related to our proprietary PEGylation materials used in the manufacture and commercialization of PEGASYS^®. As a result of Roche exercising a license extension option in December 2009, Roche has the right to manufacture all of its requirements for our proprietary PEGylation materials for PEGASYS^® and we perform additional manufacturing, if any, only on an as-requested basis. In connection with Roche’s exercise of the license extension option in December 2009, we received a payment of $31.0 million. As of December 31, 2013, we have deferred revenue of approximately $10.3 million related to this agreement, which we expect to recognize through December 2015, the period through which we are required to provide back-up manufacturing and supply services related to PEGASYS^®.

In February 2012, we entered into a toll-manufacturing agreement with Roche under which we will manufacture the proprietary PEGylation material used by Roche to produce MIRCERA^®. Roche entered into the toll-manufacturing agreement with the objective of establishing us as a secondary back-up supply source on a non-exclusive basis. Under the terms of our toll-manufacturing agreement, Roche paid us an upfront payment of $5.0 million and an additional $22.0 million in performance-based milestone payments upon our achievement of certain manufacturing readiness, validation and production milestones, including the delivery of specified quantities of PEGylation materials, all of which were completed as of January 2013. Roche will also pay us additional consideration for any future orders of the PEGylation materials for MIRCERA^® beyond the initial quantities manufactured through January 2013. Roche has the right to terminate the toll-manufacturing agreement due to an uncured material default by us.

We analyzed the milestone payments under the agreement and determined that they did not meet the criteria for revenue recognition under the milestone method as a result of our continuing manufacturing obligations. We have identified our back-up manufacturing obligation through December 2016 and the delivery of PEGylation materials specified in the agreement in 2012 and early 2013 as the units of accounting in the arrangement. We made our best estimate of the selling prices for these deliverables and have allocated the total $27.0 million consideration to these items based on the relative selling price method. As of December 31, 2013, we have deferred revenue of approximately $16.1 million, which we expect to recognize through December 2016, the estimated end of our obligations under this agreement.

In August 2013, we agreed to deliver additional quantities of PEGylation materials used by Roche to produce PEGASYS^® and MIRCERA^®, all of which were delivered in the last quarter of 2013, for total consideration of $18.6 million. We determined that these incremental activities should be considered a material modification of the existing PEGASYS^® and MIRCERA^® -related arrangements described above. As a result, we allocated the $18.6 million consideration to each of these arrangements and determined the amounts to be recognized or deferred based on the estimated selling prices of the undelivered obligations. As of December 31, 2013, we have deferred revenue of approximately $6.9 million related to these activities, which we expect to recognize through December 2016, the estimated end of our obligations under the modified arrangements.

Bayer Healthcare LLC: BAY41-6551 (Amikacin Inhale)

In August 2007, we entered into a co-development, license and co-promotion agreement with Bayer Healthcare LLC (Bayer) to develop a specially-formulated inhaled Amikacin. We are responsible for development and manufacturing and supply of the nebulizer device included in the Amikacin product. Bayer is responsible for most future clinical development and commercialization costs, all activities to support worldwide regulatory filings, approvals and related activities, further development of Amikacin Inhale and final product packaging and distribution. In the years prior to 2013, we received an upfront payment of $40.0 million in 2007 and milestone payments of $20.0 million, of which $10.0 million was recorded as a liability to Bayer for the reimbursement of its costs of the Phase 3 clinical trial.

As a result of the start of the Phase 3 clinical trial by Bayer in the treatment of intubated and mechanically ventilated patients with Gram-negative pneumonia in April 2013, we achieved a $10.0 million development milestone, which was received and recognized as revenue in the second quarter of 2013. The receipt of this milestone also triggered the payment of our $10.0 million obligation to Bayer described above, which was paid in June 2013.

In addition, we are entitled to receive a total of up to $50.0 million for development milestones upon achievement of certain development objectives, as well as sales milestones upon achievement of annual sales targets and royalties based on annual worldwide net sales of Amikacin Inhale. As of December 31, 2013, we have deferred revenue of approximately $22.5 million related to this agreement, which we expect to recognize through December 2026, the estimated end of our obligations under this agreement.

Affymax, Inc.: OMONTYS^®

In April 2004, we entered into a license, manufacturing and supply agreement with Affymax, Inc. (Affymax) under which we provided Affymax with a worldwide, non-exclusive license under certain of our proprietary PEGylation technology to develop, manufacture and commercialize OMONTYS^® (peginesatide).

On March 27, 2012, the FDA approved OMONTYS^® to treat anemia in patients with chronic kidney disease on dialysis and OMONTYS^® sales were initiated in the second quarter of 2012. On February 23, 2013, Affymax and Takeda Pharmaceutical Company Limited (Takeda) announced a voluntary recall of all lots of OMONTYS^® drug product as a result of new post-marketing reports regarding serious hypersensitivity reactions, including anaphylaxis, which can be life-threatening or fatal. Effective as of April 1, 2013, Affymax announced that it had amended its collaboration agreement with Takeda to transfer regulatory, manufacturing, and development responsibilities for OMONTYS^® to Takeda. In July 2013, Affymax terminated the license, manufacturing and supply agreement with Nektar.

We have received milestone and related payments under our agreement with Affymax and, as a result of the termination of our agreement with Affymax and our related performance obligations, we recognized the remaining $6.7 million of deferred revenue from this agreement in the year ended December 31, 2013.

Amgen, Inc.: Neulasta^®

In October 2010, we amended and restated an existing supply and license agreement by entering into a supply, dedicated suite and manufacturing guarantee agreement (the amended and restated agreement) and a license agreement with Amgen Inc. and Amgen Manufacturing, Limited (together referred to as Amgen). Under the terms of the amended and restated agreement, we guarantee the manufacture and supply of our proprietary PEGylation materials (Polymer Materials) to Amgen in an existing manufacturing suite to be used exclusively for the manufacture of Polymer Materials for Amgen (the Manufacturing Suite) in our manufacturing facility in Huntsville, Alabama (the Facility). This supply arrangement is on a non-exclusive basis (other than the use of the Manufacturing Suite and certain equipment) whereby we are free to manufacture and supply the Polymer Materials to any other third party and Amgen is free to procure the Polymer Materials from any other third party. Under the terms of the amended and restated agreement, we received a $50.0 million payment in the fourth quarter of 2010 in return for our guaranteeing the supply of certain quantities of Polymer Materials to Amgen including without limitation the Additional Rights described below and manufacturing fees that are calculated based on fixed and variable components applicable to the Polymer Materials ordered by Amgen and delivered by us. Amgen has no minimum purchase commitments. If quantities of the Polymer Materials ordered by Amgen exceed specified quantities, significant additional payments become payable to us in return for our guaranteeing the supply of additional quantities of the Polymer Materials.

The term of the amended and restated agreement ends on October 29, 2020. In the event we become subject to a bankruptcy or insolvency proceeding, we cease to own or control the Facility, we fail to manufacture and supply or certain other events, Amgen or its designated third party will have the right to elect, among certain other options, to take title to the dedicated equipment and access the Facility to operate the Manufacturing Suite solely for the purpose of manufacturing the Polymer Materials (the Additional Rights). Amgen may terminate the amended and restated agreement for convenience or due to an uncured material default by us. Our research facility in Huntsville, Alabama that we propose to sell is a different building and location from that of the Facility described here.

As of December 31, 2013, we have deferred revenue of approximately $34.2 million related to this agreement, which we expect to recognize through October 2020, the estimated end of our obligations under this agreement.

Baxter Healthcare: BAX 855/Hemophilia

In September 2005, we entered into an exclusive research, development, license and manufacturing and supply agreement with Baxter Healthcare SA and Baxter Healthcare Corporation (together referred to as Baxter) to develop products designed to improve therapies for Hemophilia A patients using our PEGylation technology. Under the terms of the agreement, we are entitled to research and development funding and are responsible for supplying Baxter with its requirements for our proprietary materials. Baxter is responsible for all clinical development, regulatory, and commercialization expenses. The agreement is terminable by the parties under customary conditions.

Under the terms of our agreement with Baxter, we are entitled to up to $28.0 million of development milestones related to Hemophilia A upon achievement of certain development objectives, as well as sales milestones upon achievement of annual sales targets and royalties based on annual worldwide net sales of products resulting from this agreement. This Hemophilia A program includes BAX 855, which is currently in a Phase 3 clinical study initiated in February 2013. In prior years, we received an upfront payment of $4.0 million related to the Hemophilia A programs. As of December 31, 2013, we do not have significant deferred revenue related to this agreement.

Other

In addition, as of December 31, 2013, we have a number of collaboration agreements, including our collaboration partners UCB, Ophthotech Corp., and Regado Biosciences, Inc., under which we are entitled to up to a total of $66.3 million of development milestones upon achievement of certain development objectives, as well as sales milestones upon achievement of annual sales targets and royalties based on net sales of commercialized products, if any. However, given the current phase of development of the potential products under these collaboration agreements, we cannot estimate the probability or timing of achieving these milestones.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

Note 11 — Stock-Based Compensation

We issue stock-based awards from our equity incentive plans, which are more fully described in Note 9. Stock-based compensation expense was recognized as follows (in thousands):


	Year Ended December 31,
	2013		2012		2011
Cost of goods sold	$	1,297	$	1,496	$	1,266
Research and development		7,910		7,082		7,944
General and administrative		8,501		7,621		9,675

Total stock-based compensation	$	17,708	$	16,199	$	18,885

As of December 31, 2013, total unrecognized compensation costs of $23.4 million related to unvested stock-based compensation arrangements are expected to be recognized as expense over a weighted-average period of 1.7 years.

Black-Scholes Assumptions

The following tables list the Black-Scholes option-pricing model assumptions used to calculate the fair value of employee and director stock options. Stock-based compensation resulting from our ESPP was not material in the years ended December 31, 2013, 2012, and 2011.


	Year Ended December 31, 2013			Year Ended December 31, 2012			Year Ended December 31, 2011
Average risk-free interest rate		0.9	%		0.9	%		1.6	%
Dividend yield		0.0	%		0.0	%		0.0	%
Average volatility factor		61.2	%		62.2	%		63.8	%
Average weighted average expected life		5.2 years			5.0 years			4.9 years

The average risk-free interest rate is based on the U.S. treasury yield curve in effect at the time of grant for periods commensurate with the expected life of the stock-based award. We have never paid dividends, nor do we expect to pay dividends in the foreseeable future; therefore, we used a dividend yield of 0.0%. Our estimate of expected volatility is based on the daily historical trading data of our common stock at the time of grant over a historical period commensurate with the expected life of the stock-based award.

For the years ended December 31, 2013, 2012, and 2011, we estimated the weighted-average expected life based on the contractual and vesting terms of the stock options, as well as historic cancellation and exercise data.

Summary of Stock Option Activity

The table below presents a summary of stock option activity under our equity incentive plans (in thousands, except for price per share and contractual life information):


	Number of Shares			Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Life (in Years)		Aggregate Intrinsic Value(1)
Outstanding at December 31, 2012		18,996		$	9.03
Options granted		3,470			9.42
Options exercised		(1,047	)		7.07
Options forfeited & canceled		(764	)		12.76

Outstanding at December 31, 2013		20,655		$	9.06		4.35	$	56,269

Vested and expected to vest at December 31, 2013		20,357		$	9.07		4.31	$	55,454
Exercisable at December 31, 2013		15,519		$	9.08		3.64	$	43,287

(1)	Aggregate intrinsic value represents the difference between the exercise price of the option and the closing market price of our common stock on December 31, 2013.

The weighted-average grant-date fair value per share of options granted during the years ended December 31, 2013, 2012, and 2011 was $4.95, $3.92, and $5.22, respectively. The total intrinsic value of options exercised during the years ended December 31, 2013, 2012, and 2011 was $4.5 million, $1.9 million, and $3.7 million, respectively. The estimated fair value of options vested during the years ended December 31, 2013, 2012, and 2011 was $14.1 million, $15.7 million, and $18.1 million, respectively.

RSU Awards

We issued RSU awards to certain officers and employees. The RSU awards granted in 2006 vested upon achievement of pre-determined performance milestones, of which the last performance milestone was met in 2013. The RSU awards granted in 2007 through 2010 had a time-based vesting schedule. There were no RSU awards granted in 2013, 2012, or 2011. There were no, 120,580, and 136,080 RSU awards outstanding at December 31, 2013, 2012, and 2011, respectively. We expensed the grant date fair value of the RSU awards ratably over the expected service or performance period.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References+ Details

Income Taxes

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Income Taxes

Note 12 — Income Taxes

Income (loss) before provision for income taxes includes the following components (in thousands):


	Year Ended December 31,
	2013			2012			2011
Domestic	$	(161,068	)	$	(174,258	)	$	(135,880	)
Foreign		1,300			2,809			2,920

Loss before provision for income taxes	$	(159,768	)	$	(171,449	)	$	(132,960	)

Provision for Income Taxes

The provision for income taxes consists of the following (in thousands):


	Year Ended December 31,
	2013			2012			2011
Current:
Federal	$	—		$	(137	)	$	—
State		1			1			1
Foreign		1,838			1,029			921

Total Current		1,839			893			922

Deferred:
Federal		422			(422	)		—
State		49			(49	)		—
Foreign		(65	)		(16	)		96

Total Deferred		406			(487	)		96

Provision for income taxes	$	2,245		$	406		$	1,018

Income tax provision related to continuing operations differs from the amount computed by applying the statutory income tax rate of 35% to pretax loss as follows (in thousands):


	Year Ended December 31,
	2013			2012			2011
U.S. federal provision (benefit)
At statutory rate	$	(55,919	)	$	(60,007	)	$	(46,536	)
State taxes		50			(48	)		1
Change in valuation allowance		55,042			47,349			48,959
Foreign tax inclusion		—			6,510			—
Non-cash interest expense on liability related to sale of future royalties		7,808			6,320			—
Foreign tax differential		(20	)		(227	)		(129	)
Research credits		(6,273	)		(591	)		(893	)
Other		1,557			1,100			(384	)

Provision for income taxes	$	2,245		$	406		$	1,018

Deferred Tax Assets and Liabilities

Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets for federal and state income taxes are as follows (in thousands):


	December 31,
	2013			2012
Deferred tax assets:
Net operating loss carryforwards	$	391,385		$	351,354
Research and other credits		61,707			52,769
Deferred revenue		35,588			39,521
Sale of future royalties		28,057			39,750
Stock-based compensation		25,962			23,746
Capitalized research expenses		17,687			7,192
Reserves and accruals		14,685			8,776
Property and equipment		8,580			8,482
Other		2,539			2,773

Deferred tax assets before valuation allowance		586,190			534,363
Valuation allowance for deferred tax assets		(586,040	)		(534,268	)

Total deferred tax assets		150			95

Total deferred tax liabilities		—			—

Net deferred tax assets	$	150		$	95

Realization of our deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Because of our lack of U.S. earnings history, the net U.S. deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $51.8 million and $43.6 million during the years ended December 31, 2013 and 2012, respectively. The valuation allowance includes approximately $35.6 million of income tax benefit at both December 31, 2013 and December 31, 2012 related to stock-based compensation and exercises prior to the implementation of the accounting guidance for stock-based compensation that will be credited to additional paid in capital when realized.

Undistributed earnings of our foreign subsidiary in India are considered to be permanently reinvested and accordingly, no deferred U.S. income taxes have been provided thereon. Upon distribution of those earnings in the form of dividends or otherwise, we would be subject to U.S. income tax. As of December 31, 2013, U.S. income taxes have not been provided on a cumulative total of $1.7 million of such earnings. At the present time it is not practicable to estimate the amount of U.S. income taxes that might be payable if these earnings were repatriated.

Net Operating Loss and Tax Credit Carryforwards

As of December 31, 2013, we had a net operating loss carryforward for federal income tax purposes of approximately $1,029.7 million, portions of which will begin to expire in 2018. We had a total state net operating loss carryforward of approximately $614.6 million, which will begin to expire in 2014. Utilization of some of the federal and state net operating loss and credit carryforwards are subject to annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986 and similar state provisions. The annual limitations may result in the expiration of net operating losses and credits before utilization.

We have federal research credits of approximately $36.5 million, which will begin to expire in 2019 and state research credits of approximately $20.9 million which have no expiration date. We have federal orphan drug credits of $17.7 million which will begin to expire in 2026. These tax credits are subject to the same limitations discussed above.

Unrecognized tax benefits

We have incurred net operating losses since inception. Our policy is to include interest and penalties related to unrecognized tax benefits, if any, within the provision for income taxes in the consolidated statements of operations. If we are eventually able to recognize our uncertain positions, our effective tax rate would be reduced. We currently have a full valuation allowance against our U.S. net deferred tax asset which would impact the timing of the effective tax rate benefit should any of these uncertain tax positions be favorably settled in the future. Any adjustments to our uncertain tax positions would result in an adjustment of our net operating loss or tax credit carry forwards rather than resulting in a cash outlay.

We file income tax returns in the U.S., California, Alabama, India and the U.K. The 2009 and 2010 tax years were previously under audit by the IRS. These audits were completed and we received no change letters. The 2005 through 2010 tax years were previously under audit in Alabama. These audits were completed with no changes to the tax liability. Because of net operating losses and research credit carryovers, substantially all of our domestic tax years remain open and subject to examination. We are currently under examination in India for the fiscal years ending 2009 through 2013.

We have the following activity relating to unrecognized tax benefits (in thousands):


	December 31,
	2013		2012			2011
Beginning balance	$	14,067	$	13,576		$	13,058
Tax positions related to current year
Additions:
Federal		477		289			297
State		381		302			221
Reductions		—		—			—
Tax positions related to prior year
Additions:
Federal		636		37			—
State		—		—			—
Foreign		802		—			—
Reductions		—		—			—
Settlements		—		—			—
Lapses in statute of limitations		—		(137	)		—

Ending balance	$	16,363	$	14,067		$	13,576

Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next twelve months due to tax examination changes, settlement activities, expirations of statute of limitations, or the impact on recognition and measurement considerations related to the results of published tax cases or other similar activities, we do not anticipate any significant changes to unrecognized tax benefits over the next twelve months. During the years ended December 31, 2013, 2012 and 2011, no significant interest or penalties were recognized relating to unrecognized tax benefits.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References+ Details

Segment Reporting

12 Months Ended

Dec. 31, 2013

Segment Reporting [Abstract]

Segment Reporting

Note 13 — Segment Reporting

We operate in one business segment which focuses on applying our technology platforms to improve the performance of established and novel medicines. We operate in one segment because our business offerings have similar economics and other characteristics, including the nature of products and manufacturing processes, types of customers, distribution methods and regulatory environment. We are comprehensively managed as one business segment by our Chief Executive Officer and his management team. Within our one business segment we have two components, PEGylation technology and pulmonary technology.

Our revenue is derived primarily from clients in the pharmaceutical and biotechnology industries. Roche, UCB, AstraZeneca, and Bayer represented 28%, 21%, 17% and 10% of our revenue, respectively, for the year ended December 31, 2013. Revenue from UCB, Roche and Affymax represented 30%, 23%, and 11% of our revenue, respectively, for the year ended December 31, 2012. Revenue from UCB and Roche represented 27% and 16% of our revenue, respectively, for the year ended December 31, 2011.

Revenue by geographic area is based on the locations of our partners. The following table sets forth revenue by geographic area (in thousands):


	Year Ended December 31,
	2013		2012		2011
United States	$	42,535	$	34,591	$	37,896
Europe		106,386		46,600		33,584

Total revenue	$	148,921	$	81,191	$	71,480

At December 31, 2013, $57.3 million, or approximately 88%, of the net book value of our property and equipment was located in the United States and $7.7 million, or approximately 12%, was located in India. At December 31, 2012, $62.5 million, or approximately 87%, of the net book value of our property and equipment was located in the United States and $9.7 million, or approximately 13%, was located in India.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8380-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 32

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8933-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8538-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8844-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 29

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8864-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 35

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8984-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 41

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 30

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8906-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 42

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 31

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 40

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8971-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8595-108599

+ Details

Selected Quarterly Financial Data

12 Months Ended

Dec. 31, 2013

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data

Note 15 — Selected Quarterly Financial Data (Unaudited)

The following table sets forth certain unaudited quarterly financial data. In our opinion, the unaudited information set forth below has been prepared on the same basis as the audited information and includes all adjustments necessary to present fairly the information set forth herein. We have experienced fluctuations in our quarterly results and expect these fluctuations to continue in the future. Due to these and other factors, we believe that quarter-to-quarter comparisons of our operating results will not be meaningful, and you should not rely on our results for any one quarter as an indication of our future performance. Certain items previously reported in specific financial statement captions have been reclassified to conform to the current period presentation. Such reclassifications have not materially impacted previously reported total revenues, operating loss or net loss. All data is in thousands except per share information.


	Fiscal Year 2013												Fiscal Year 2012
	Q1			Q2			Q3			Q4			Q1			Q2			Q3			Q4
Product sales	$	11,810		$	10,324		$	14,672		$	8,040		$	6,945		$	9,694		$	8,355		$	10,405
Total revenue	$	23,004		$	33,862		$	60,909		$	31,146		$	17,949		$	23,684		$	18,412		$	21,146
Cost of goods sold	$	11,661		$	5,011		$	12,877		$	8,960		$	8,707		$	7,203		$	7,228		$	7,290
Research and development expenses	$	45,618		$	52,230		$	43,914		$	48,248		$	35,085		$	33,201		$	34,016		$	46,373
Operating loss	$	(45,106	)	$	(32,605	)	$	(6,525	)	$	(35,894	)	$	(37,932	)	$	(26,988	)	$	(32,900	)	$	(43,381	)
Net loss	$	(55,063	)	$	(42,748	)	$	(16,543	)	$	(47,659	)	$	(41,097	)	$	(34,285	)	$	(43,547	)	$	(52,926	)
Basic and diluted net loss per share(1)	$	(0.48	)	$	(0.37	)	$	(0.14	)	$	(0.41	)	$	(0.36	)	$	(0.30	)	$	(0.38	)	$	(0.46	)

(1)	Quarterly loss per share amounts may not total to the year-to-date loss per share due to rounding.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References+ Details

Organization and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Organization

Note 1 — Organization and Summary of Significant Accounting Policies

Organization

Basis of Presentation, Principles of Consolidation and Use of Estimates

Basis of Presentation, Principles of Consolidation and Use of Estimates

Reclassifications

Reclassifications

Cash, Cash Equivalents, and Investments, and Fair Value of Financial Instruments

Cash, Cash Equivalents, and Investments, and Fair Value of Financial Instruments

Accounts Receivable and Significant Customer Concentrations

Accounts Receivable and Significant Customer Concentrations

Inventory and Significant Supplier Concentrations

Inventory and Significant Supplier Concentrations

Property and Equipment

Property and Equipment

Goodwill

Goodwill

Revenue Recognition

Revenue Recognition

Product sales

Royalty revenues

License, collaboration and other

Shipping and Handling Costs

Shipping and Handling Costs

We recognize costs related to shipping and handling of product to customers in cost of goods sold.

Stock-Based Compensation

Stock-Based Compensation

Research and Development Expense

Research and Development Expense

Net Loss Per Share

Net Loss Per Share


	Year Ended December 31,
	2013		2012		2011
Stock options		12,959		13,970		11,338
Convertible subordinated notes		—		—		9,989

Total		12,959		13,970		21,327

Income Taxes

Income Taxes

Comprehensive Loss

Comprehensive loss

Recent Accounting Pronouncements

Recent Accounting Pronouncements

Organization and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Weighted Average Securities Excluded from Diluted Net Loss Per Share

The weighted average of these potentially dilutive securities has been excluded from the diluted net loss per share calculation and is as follows (in thousands):


	Year Ended December 31,
	2013		2012		2011
Stock options		12,959		13,970		11,338
Convertible subordinated notes		—		—		9,989

Total		12,959		13,970		21,327

Cash and Investments in Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Cash and Investments in Marketable Securities, Including Cash Equivalents and Restricted Cash

Cash and investments in marketable securities, including cash equivalents and restricted cash, are as follows (in thousands):


	Estimated Fair Value at
	December 31, 2013		December 31, 2012
Cash and cash equivalents	$	39,067	$	25,437
Short-term investments		197,959		251,757
Restricted cash		25,000		25,000

Total cash and investments in marketable securities	$	262,026	$	302,194

Portfolio of Cash and Investments in Marketable Securities

Our portfolio of cash and investments in marketable securities includes (in thousands):


	Fair Value Hierarchy Level		Estimated Fair Value at
	Fair Value Hierarchy Level		December 31, 2013		December 31, 2012
Corporate notes and bonds		2	$	138,515	$	241,158
U.S. corporate commercial paper		2		59,444		3,990
Obligations of U.S. government agencies		2		—		6,108
Obligations of U.S. states and municipalities		2		—		1,504

Available-for-sale investments				197,959		252,760
Money market funds		1		26,453		22,487
Cash, including restricted cash		N/A		37,614		26,947

Total cash and investments in marketable securities			$	262,026	$	302,194

Inventory (Tables)

12 Months Ended

Dec. 31, 2013

Inventory Disclosure [Abstract]

Inventory

Inventory consists of the following (in thousands):


	December 31,
	2013		2012
Raw materials	$	3,947	$	7,489
Work-in-process		6,146		6,661
Finished goods		3,359		4,119

Inventory	$	13,452	$	18,269

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2013

Property Plant And Equipment [Abstract]

Property and Equipment

Property and equipment consist of the following (in thousands):


	December 31,
	2013			2012
Building and leasehold improvements	$	71,306		$	72,180
Laboratory equipment		26,621			27,145
Manufacturing equipment		23,699			20,877
Furniture, fixtures and other equipment		23,235			21,914

Depreciable property and equipment at cost		144,861			142,116
Less: accumulated depreciation		(84,148	)		(72,666	)

Depreciable property and equipment, net		60,713			69,450
Construction-in-progress		6,261			2,765

Property and equipment, net	$	66,974		$	72,215

Leases (Tables)

12 Months Ended

Dec. 31, 2013

Text Block [Abstract]

Future Minimum Payments for Capital Leases

Future minimum payments for our capital leases at December 31, 2013 are as follows (in thousands):


Years ending December 31,
2014	$	5,169
2015		5,280
2016		4,034

Total minimum payments required		14,483
Less: amount representing interest		(2,898	)

Present value of future minimum lease payments		11,585
Less: current portion		(3,536	)

Capital lease obligation, less current portion	$	8,049

Future Minimum Lease Payments for Operating Leases

Our future minimum lease payments for our operating leases at December 31, 2013 are as follows (in thousands):


Years ending December 31,
2014	$	2,559
2015		4,750
2016		4,892
2017		5,037
2018		5,187
2019 and thereafter		5,796

Total future minimum lease payments	$	28,221

Liability Related to Sale of Future Royalties (Tables)

12 Months Ended

Dec. 31, 2013

Text Block [Abstract]

Summary of Liability Related to Potential Future Royalties


	Year ended December 31, 2013			Period from inception to December 31, 2013
Liability related to sale of future royalties—beginning balance	$	131,266		$	—
Proceeds from sale of future royalties		—			124,000
Non-cash interest expense recognized		22,309			40,366
Non-cash CIMZIA^® and MIRCERA^® royalty revenue		(22,055	)		(32,846	)
Payments from Nektar to RPI		(3,000	)		(3,000	)

Total liability related to sale of future royalties as of December 31, 2013		128,520			128,520
Less: current portion		(7,000	)		(7,000	)

Liability related to sale of future royalties, less current portion	$	121,520		$	121,520

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Summarization of Common Stock Shares for Issuance Under Existing Equity Compensation Plans


Plan Category	Number of Securities to be Issued Upon Exercise of Outstanding Options (a)		Weighted-Average Exercise Price of Outstanding Options (b)		Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column(a)) (c)
Equity compensation plans approved by security holders(1)		14,936	$	8.76		7,954
Equity compensation plans not approved by security holders		5,719	$	9.84		—

Total		20,655	$	9.06		7,954

(1)	Includes shares of common stock available for future issuance under our ESPP as of December 31, 2013.

License and Collaboration Agreements (Tables)

12 Months Ended

Dec. 31, 2013

Organization Consolidation And Presentation Of Financial Statements [Abstract]

License, Collaboration and Other Revenue

In accordance with our collaboration agreements, we recognized license, collaboration and other revenue as follows (in thousands):


		Year Ended December 31,
Partner	Agreement	2013		2012		2011
AstraZeneca AB	Naloxegol (NKTR-118) and naloxegol fixed-dose combination program (NKTR-119)	$	25,016	$	59	$	2,496
Roche	PEGASYS^® and MIRCERA^®		18,382		7,146		5,131
Bayer Healthcare LLC	BAY41-6551 (Amikacin Inhale)		15,293		2,971		2,992
Affymax, Inc.	OMONTYS^®		7,149		2,829		3,838
Amgen, Inc.	Neulasta^®		5,035		5,000		5,000
Baxter Healthcare	BAX 855 (Hemophilia)		1,702		6,238		5,646
Other			8,295		5,884		11,186

License, collaboration and other revenue		$	80,872	$	30,127	$	36,289

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense

Stock-based compensation expense was recognized as follows (in thousands):


	Year Ended December 31,
	2013		2012		2011
Cost of goods sold	$	1,297	$	1,496	$	1,266
Research and development		7,910		7,082		7,944
General and administrative		8,501		7,621		9,675

Total stock-based compensation	$	17,708	$	16,199	$	18,885

Black-Scholes Option-Pricing Model Assumptions Used to Calculate Fair Value of Employee Stock Options


	Year Ended December 31, 2013			Year Ended December 31, 2012			Year Ended December 31, 2011
Average risk-free interest rate		0.9	%		0.9	%		1.6	%
Dividend yield		0.0	%		0.0	%		0.0	%
Average volatility factor		61.2	%		62.2	%		63.8	%
Average weighted average expected life		5.2 years			5.0 years			4.9 years

Stock Option Activity Under Equity Incentive Plans

The table below presents a summary of stock option activity under our equity incentive plans (in thousands, except for price per share and contractual life information):


	Number of Shares			Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Life (in Years)		Aggregate Intrinsic Value(1)
Outstanding at December 31, 2012		18,996		$	9.03
Options granted		3,470			9.42
Options exercised		(1,047	)		7.07
Options forfeited & canceled		(764	)		12.76

Outstanding at December 31, 2013		20,655		$	9.06		4.35	$	56,269

Vested and expected to vest at December 31, 2013		20,357		$	9.07		4.31	$	55,454
Exercisable at December 31, 2013		15,519		$	9.08		3.64	$	43,287

(1)	Aggregate intrinsic value represents the difference between the exercise price of the option and the closing market price of our common stock on December 31, 2013.

- Definition

Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate.

+ References+ Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Income (Loss) Before Provision for Income Taxes

Income (loss) before provision for income taxes includes the following components (in thousands):


	Year Ended December 31,
	2013			2012			2011
Domestic	$	(161,068	)	$	(174,258	)	$	(135,880	)
Foreign		1,300			2,809			2,920

Loss before provision for income taxes	$	(159,768	)	$	(171,449	)	$	(132,960	)

Provision for Income Taxes

The provision for income taxes consists of the following (in thousands):


	Year Ended December 31,
	2013			2012			2011
Current:
Federal	$	—		$	(137	)	$	—
State		1			1			1
Foreign		1,838			1,029			921

Total Current		1,839			893			922

Deferred:
Federal		422			(422	)		—
State		49			(49	)		—
Foreign		(65	)		(16	)		96

Total Deferred		406			(487	)		96

Provision for income taxes	$	2,245		$	406		$	1,018

Income Tax Provision Related to Continuing Operations

Income tax provision related to continuing operations differs from the amount computed by applying the statutory income tax rate of 35% to pretax loss as follows (in thousands):


	Year Ended December 31,
	2013			2012			2011
U.S. federal provision (benefit)
At statutory rate	$	(55,919	)	$	(60,007	)	$	(46,536	)
State taxes		50			(48	)		1
Change in valuation allowance		55,042			47,349			48,959
Foreign tax inclusion		—			6,510			—
Non-cash interest expense on liability related to sale of future royalties		7,808			6,320			—
Foreign tax differential		(20	)		(227	)		(129	)
Research credits		(6,273	)		(591	)		(893	)
Other		1,557			1,100			(384	)

Provision for income taxes	$	2,245		$	406		$	1,018

Significant Components of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets for federal and state income taxes are as follows (in thousands):


	December 31,
	2013			2012
Deferred tax assets:
Net operating loss carryforwards	$	391,385		$	351,354
Research and other credits		61,707			52,769
Deferred revenue		35,588			39,521
Sale of future royalties		28,057			39,750
Stock-based compensation		25,962			23,746
Capitalized research expenses		17,687			7,192
Reserves and accruals		14,685			8,776
Property and equipment		8,580			8,482
Other		2,539			2,773

Deferred tax assets before valuation allowance		586,190			534,363
Valuation allowance for deferred tax assets		(586,040	)		(534,268	)

Total deferred tax assets		150			95

Total deferred tax liabilities		—			—

Net deferred tax assets	$	150		$	95

Unrecognized Tax Benefits

We have the following activity relating to unrecognized tax benefits (in thousands):


	December 31,
	2013		2012			2011
Beginning balance	$	14,067	$	13,576		$	13,058
Tax positions related to current year
Additions:
Federal		477		289			297
State		381		302			221
Reductions		—		—			—
Tax positions related to prior year
Additions:
Federal		636		37			—
State		—		—			—
Foreign		802		—			—
Reductions		—		—			—
Settlements		—		—			—
Lapses in statute of limitations		—		(137	)		—

Ending balance	$	16,363	$	14,067		$	13,576

Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2013

Segment Reporting [Abstract]

Revenue by Geographic Area

Revenue by geographic area is based on the locations of our partners. The following table sets forth revenue by geographic area (in thousands):


	Year Ended December 31,
	2013		2012		2011
United States	$	42,535	$	34,591	$	37,896
Europe		106,386		46,600		33,584

Total revenue	$	148,921	$	81,191	$	71,480

Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2013

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data


	Fiscal Year 2013												Fiscal Year 2012
	Q1			Q2			Q3			Q4			Q1			Q2			Q3			Q4
Product sales	$	11,810		$	10,324		$	14,672		$	8,040		$	6,945		$	9,694		$	8,355		$	10,405
Total revenue	$	23,004		$	33,862		$	60,909		$	31,146		$	17,949		$	23,684		$	18,412		$	21,146
Cost of goods sold	$	11,661		$	5,011		$	12,877		$	8,960		$	8,707		$	7,203		$	7,228		$	7,290
Research and development expenses	$	45,618		$	52,230		$	43,914		$	48,248		$	35,085		$	33,201		$	34,016		$	46,373
Operating loss	$	(45,106	)	$	(32,605	)	$	(6,525	)	$	(35,894	)	$	(37,932	)	$	(26,988	)	$	(32,900	)	$	(43,381	)
Net loss	$	(55,063	)	$	(42,748	)	$	(16,543	)	$	(47,659	)	$	(41,097	)	$	(34,285	)	$	(43,547	)	$	(52,926	)
Basic and diluted net loss per share(1)	$	(0.48	)	$	(0.37	)	$	(0.14	)	$	(0.41	)	$	(0.36	)	$	(0.30	)	$	(0.38	)	$	(0.46	)

(1)	Quarterly loss per share amounts may not total to the year-to-date loss per share due to rounding.

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Reporting_Unit Customer	Dec. 31, 2012 Customer	Dec. 31, 2011	Jul. 11, 2012
Organization And Summary Of Significant Accounting Policies [Line Items]
Cash, cash equivalents and investments in marketable securities	$ 262,000,000
Indebtedness	160,800,000
Senior secured notes, issued	125,000,000	125,000,000
Senior Secured Notes, interest rate	12.00%
Restricted Cash	25,000,000	25,000,000		25,000,000
Maximum maturity term of investments in marketable securities to be considered as cash equivalents	Three months
Maturity term of investments considered as short-term	Less than one year
Number of customers accounted for major accounts receivable	3	4
Percentage of accounts receivable customers one	30.00%	38.00%
Percentage of accounts receivable customers two	28.00%	27.00%
Percentage of accounts receivable customers three	28.00%	14.00%
Percentage of accounts receivable customers four		11.00%
Number of reporting unit evaluated for goodwill	1
Impairment charges related to goodwill	0	0	0
Minimum percentage of amount realized upon ultimate settlement	50.00%
12% Senior Secured Notes Due July 2017 [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Senior Secured Notes, interest rate	12.00%
Maturity date of senior secured notes	Jul. 15, 2017
Minimum [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	3
Maximum [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Contingent payment related to royalty obligation	$ 7,000,000
Property and equipment estimated useful lives	7

Organization and Summary of Significant Accounting Policies - Weighted Average Securities Excluded from Diluted Net Loss Per Share (Detail) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average diluted securities excluded from diluted net loss per share	12,959	13,970	21,327
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average diluted securities excluded from diluted net loss per share	12,959	13,970	11,338
Convertible Subordinated Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average diluted securities excluded from diluted net loss per share			9,989

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References+ Details

Cash, Cash Equivalents, and Available-For-Sale Investments - Cash and Investments in Marketable Securities, Including Cash Equivalents and Restricted Cash (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Jul. 11, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Cash Equivalents And Available For Sale Investments [Abstract]
Cash and cash equivalents	$ 39,067	$ 25,437		$ 15,312	$ 17,755
Short-term investments	197,959	251,757
Restricted Cash	25,000	25,000	25,000
Total cash and investments in marketable securities	$ 262,026	$ 302,194

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References+ Details

Cash, Cash Equivalents, and Available-For-Sale Investments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 11, 2012
Cash Cash Equivalents And Available For Sale Investments [Abstract]
Maximum maturity term for debt securities investment	Two years or less
Weighted average maturity term for debt securities investment	One year or less
Available-for-sale securities, sold	$ 2,900,000	$ 5,400,000	$ 210,100,000
Restricted Cash	25,000,000	25,000,000		25,000,000
Senior Secured Notes, interest rate	12.00%
Senior Secured Notes, maturity date	2017-07
Level 1 to level 2 transfers	0	0
Level 2 to level 1 transfers	0	0
Letter of credit	$ 2,400,000	$ 2,400,000

Cash, Cash Equivalents, and Available-For-Sale Investments - Portfolio of Cash and Investments in Marketable Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments	$ 197,959	$ 252,760
Cash, including restricted cash	37,614	26,947
Total cash and investments in marketable securities	262,026	302,194
Corporate Notes and Bonds [Member] \| Fair Value Hierarchy Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments	138,515	241,158
U.S. Corporate Commercial Paper [Member] \| Fair Value Hierarchy Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments	59,444	3,990
Obligations of U.S. Government Agencies [Member] \| Fair Value Hierarchy Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments		6,108
Obligations of U.S. States and Municipalities [Member] \| Fair Value Hierarchy Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments		1,504
Money Market Funds [Member] \| Fair Value Hierarchy Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Money market funds	$ 26,453	$ 22,487

Inventory - Inventory (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 3,947	$ 7,489
Work-in-process	6,146	6,661
Finished goods	3,359	4,119
Inventory	$ 13,452	$ 18,269

Property and Equipment - Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciable property and equipment at cost	$ 144,861	$ 142,116
Less: accumulated depreciation	(84,148)	(72,666)
Depreciable property and equipment, net	60,713	69,450
Construction-in-progress	6,261	2,765
Property and equipment, net	66,974	72,215
Building and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Depreciable property and equipment at cost	71,306	72,180
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciable property and equipment at cost	26,621	27,145
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciable property and equipment at cost	23,699	20,877
Furniture, Fixtures and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciable property and equipment at cost	$ 23,235	$ 21,914

Senior Secured Notes - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended		1 Months Ended	0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jul. 11, 2012	Jul. 31, 2012 12% Senior Secured Notes Due July 2017 [Member]	Jul. 11, 2012 12% Senior Secured Notes Due July 2017 [Member]	Jul. 31, 2012 Convertible Subordinated Notes [Member]	Dec. 31, 2013 12% Senior Secured Notes Due July 2017 [Member]	Dec. 31, 2013 Jul 1, 2015 through June 30, 2017 [Member]
Line of Credit Facility [Line Items]
Senior secured notes, issued	$ 125,000,000	$ 125,000,000			$ 125,000,000
Maturity date of senior secured notes				Jul. 15, 2017			Jul. 15, 2017
Retirement of convertible subordinated notes						42,500,000
Interest rate	12.00%				12.00%		12.00%
Issuance costs				4,500,000
Convertible subordinated notes remaining			172,400,000
Maturity date of convertible subordinated notes	Sep. 28, 2012
Restricted Cash	25,000,000	25,000,000	25,000,000
Minimum Cash Requirement (Jul 1, 2015 through June 30, 2017)								25,000,000
Percentage of repurchase of notes on principal amount of notes	101.00%
Percentage of repurchase of notes on principal amount of notes	100.00%
Senior Secured Notes carrying amount							$ 125,000,000

Leases - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 28, 2011 sqft	Sep. 30, 2009 Pfizer, Inc. [Member] sqft
Leases [Line Items]
Percentage ceiling on rent increases, annually, capital lease	3.00%
San Carlos facility capital leases, termination date	Oct. 05, 2016
Impairment charge				$ 12.6
Net book value of assets	1.0	1.4
Book value of assets, gross	2.3	2.3
Future minimum rental receipts under the San Carlos facility subleases	7.4
Operating sublease						102,283
Operating Sublease term commenced start date	August 2010
Operating Sublease term commenced period	114 months
Operating Sublease term commenced end date	January 31, 2020
Additional area included in operating sublease due to expansion of Mission Bay Facility					24,002
Operating Sublease term commenced period expansion	December 28, 2011
Operating Sublease term commenced end date expansion	January 31, 2020
Rent expense for operating leases	$ 2.9	$ 2.8	$ 2.4

Leases - Future Minimum Payments for Capital Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
2014	$ 5,169
2015	5,280
2016	4,034
Total minimum payments required	14,483
Less: amount representing interest	(2,898)
Present value of future minimum lease payments	11,585
Less: current portion	(3,536)
Capital lease obligation, less current portion	$ 8,049	$ 11,607

- Definition

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal, through the balance sheet date and due to be paid more than one year (or one operating cycle, if longer) after the balance sheet date.

+ References+ Details

Leases - Future Minimum Lease Payments for Operating Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
Leases [Abstract]
2014	$ 2,559
2015	4,750
2016	4,892
2017	5,037
2018	5,187
2019 and thereafter	5,796
Total future minimum lease payments	$ 28,221

Liability Related to Sale of Future Royalties - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Maximum [Member]	Mar. 31, 2013 Milestone Scenario One [Member]	Dec. 31, 2013 Milestone Scenario One [Member]	Dec. 31, 2013 Milestone Scenario Two [Member]	Dec. 31, 2013 Milestone Scenario Two [Member]	Feb. 24, 2012 Purchase and Sale Agreement with RPI [Member]	Dec. 31, 2013 MIRCERA [Member]	Dec. 31, 2013 CIMZIA and MIRCERA [Member]	Dec. 31, 2012 CIMZIA and MIRCERA [Member]
Liability Related to Sale of Future Royalties [Line Items]
Proceeds from sale of royalty rights								$ 124,000,000
Transaction costs related to sale of potential future royalties								4,400,000
Increase in non-cash royalty revenue in 2013 based on estimates of net sales	4,600,000
Non-cash royalties from net sales										22,100,000	10,800,000
Annual interest rate	17.00%
Payment made for milestone not achieved year one				3,000,000
Potential payments milestone not achieved year two						7,000,000
Royalty agreement contingent payment description					Because worldwide net sales of MIRCERAfor the 12 month period ended December 31, 2012 did not reach a required threshold.		If the specified worldwide net sales threshold of MIRCERAfor the 12 month period ended December 31, 2013 is not achieved.
Contingent payment related to royalty obligation			7,000,000
Other current liabilities	$ 14,123,000	$ 9,414,000							$ 7,000,000

Liability Related to Sale of Future Royalties - Summary of Liability Related to Potential Future Royalties (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended		22 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Other Liabilities Disclosure [Abstract]
Liability related to sale of future royalties-beginning balance	$ 131,266
Proceeds from sale of future royalties			124,000
Non-cash interest expense recognized	22,309		40,366
Non-cash CIMZIA®and MIRCERA®royalty revenue	(22,055)	(10,791)	(32,846)
Payments from Nektar to RPI	(3,000)		(3,000)
Total liability related to sale of future royalties as of December 31, 2013	128,520		128,520
Less: current portion	(7,000)	(3,000)	(7,000)
Liability related to sale of future royalties, less current portion	$ 121,520	$ 128,266	$ 121,520

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Contingencies And Commitments [Line Items]
Royalty expense	$ 4,100,000	$ 2,900,000	$ 1,800,000
Purchase commitments related to contract manufacturing, clinical development and certain other items	12,600,000
Litigation settlement payment description	August 1, 2007, between us (and our subsidiaries) and Bayer Healthcare LLC, as amended, related to the inhaled amikacin program in exchange for (i) a $5.0 million payment due on April 1, 2014; (ii) a $5.0 million payment due on January 1, 2015, (iii) a series of four $500,000 payments each due on April 1, 2014, January 1, 2015, January 1, 2016, and January 1, 2017, respectively; and (iv) certain other terms and conditions.
Total litigation settlement payments	12,000,000
Discount rate	8.00%
Securities Related Claims [Member]
Contingencies And Commitments [Line Items]
Obligations under Director and Officer Indemnifications per incident	1,000,000
Non-securities Related Claims [Member]
Contingencies And Commitments [Line Items]
Obligations under Director and Officer Indemnifications per incident	500,000
Indemnification Agreement [Member]
Contingencies And Commitments [Line Items]
Indemnification Obligations, liabilities	0	0
Research and development expense [Member]
Contingencies And Commitments [Line Items]
Present value of settlement payments	11,300,000
Other Current Liabilities [Member]
Contingencies And Commitments [Line Items]
Current portion of settlement liability	5,500,000
April 1, 2014 [Member]
Contingencies And Commitments [Line Items]
Settlement installment payment due	5,000,000
Settlement installment series payment due	500,000
January 1, 2015 [Member]
Contingencies And Commitments [Line Items]
Settlement installment payment due	5,000,000
Settlement installment series payment due	500,000
January 1, 2016 [Member]
Contingencies And Commitments [Line Items]
Settlement installment series payment due	500,000
January 1, 2017 [Member]
Contingencies And Commitments [Line Items]
Settlement installment series payment due	$ 500,000

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended							12 Months Ended		1 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 2012 Performance Incentive Plan [Member]	Dec. 31, 2013 2012 Performance Incentive Plan [Member] Employee [Member]	Dec. 31, 2013 2012 Performance Incentive Plan [Member] Director [Member]	Dec. 31, 2013 Restricted Stock Units [Member]	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	Dec. 31, 2013 2000 Non-Officer Equity Incentive Plan [Member]	Jan. 31, 2011 Common Shares [Member]	Dec. 31, 2013 Common Shares [Member]	Jan. 24, 2011 Common Shares [Member]	Jan. 28, 2014 Common Shares [Member] Subsequent Event [Member]	Jan. 31, 2014 Common Shares [Member] Subsequent Event [Member]	Dec. 31, 2013 Preferred Stock [Member]	Dec. 31, 2013 Series A Preferred Stock [Member]	Dec. 31, 2012 Series A Preferred Stock [Member]	Dec. 31, 2011 Series A Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Preferred stock, shares authorized	10,000,000	10,000,000													10,000,000
Preferred stock, par value	$ 0.0001	$ 0.0001													$ 0.0001
Preferred stock, shares designated	0	0														0	0	3,100,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares issued	116,494,000	115,259,000										19,000,000	9,775,000
Proceeds from sale of common stock			$ 219,783,000							$ 220,400,000			$ 117,200,000	$ 117,200,000
Legal, accounting fees, filing fees and other offering expenses										600,000			600,000	600,000
Common stock, shares reserved for issuance in equity compensation plans											28,609,480
Additional new shares available for award grants				5,300,000
Service period for stock options granted					4 years	1 year
Number of common stock shares available for stock options grants				10,347,140
Share-based compensation plan's share limit reduction for every one restricted stock unit granted				1.5
Maximum term of stock options under equity incentive plans				8 years
Maximum term of stock options under equity incentive plans									8 years
Restricted Stock Units outstanding	0
RSU awards par value	$ 0.0001	$ 0.0001					$ 0.01
Restricted stock units award depletion ratio	1:1.5
Common stock, shares authorized	300,000,000	300,000,000						1,500,000
Percentage of purchase price of stock								85.00%
Maximum 401(k) per employee, percentage of annual salary	60.00%
Matching 401(k) employer contribution, maximum amount	3,000
Compensation expense in connection with 401(k) retirement plan	$ 1,000,000	$ 900,000	$ 900,000
Severance payment period for executives	12 months
Severance payment period for employees	6 months
Cash severance payment for chief executive officer	24 months base salary plus annual target incentive pay

Stockholders' Equity - Summarization of Common Stock Shares for Issuance Under Existing Equity Compensation Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Securities to be Issued Upon Exercise of Outstanding Options	20,655
Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column)	7,954
Weighted-Average Exercise Price of Outstanding Options	$ 9.06
Equity Compensation Plans Approved by Security Holders [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Securities to be Issued Upon Exercise of Outstanding Options	14,936
Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column)	7,954
Weighted-Average Exercise Price of Outstanding Options	$ 8.76
Equity Compensation Plans Not Approved by Security Holders [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Securities to be Issued Upon Exercise of Outstanding Options	5,719
Number of Securities Remaining Available for Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Column)
Weighted-Average Exercise Price of Outstanding Options	$ 9.84

License and Collaboration Agreements - License, Collaboration and Other Revenue (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	$ 80,872	$ 30,127	$ 36,289
AstraZeneca AB [Member] \| Naloxegol (NKTR-118) and Naloxegol Fixed-dose Combination Program (NKTR-119) [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	25,016	59	2,496
Roche [Member] \| PEGASYS and MIRCERA [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	18,382	7,146	5,131
Bayer Healthcare LLC [Member] \| BAY41-6551 (Amikacin Inhale) [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	15,293	2,971	2,992
Affymax, Inc. [Member] \| OMONTYS [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	7,149	2,829	3,838
Amgen, Inc. [Member] \| Neulasta [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	5,035	5,000	5,000
Baxter Healthcare [Member] \| BAX 855 (Hemophilia) [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	1,702	6,238	5,646
Other [Member]
License And Collaboration Agreements [Line Items]
License, collaboration and other revenue	$ 8,295	$ 5,884	$ 11,186

License and Collaboration Agreements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended	0 Months Ended		0 Months Ended						3 Months Ended	0 Months Ended				1 Months Ended	3 Months Ended	12 Months Ended	1 Months Ended	2 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 25, 2013 Naloxegol [Member]	Dec. 31, 2013 Naloxegol [Member] US and EU Commercial Launch [Member]	Sep. 16, 2013 AstraZeneca AB [Member]	Sep. 16, 2013 AstraZeneca AB [Member] January 15, 2015 [Member]	Sep. 16, 2013 AstraZeneca AB [Member] Second Installment [Member]	Sep. 16, 2013 AstraZeneca AB [Member] January 15, 2017 [Member]	Sep. 16, 2013 AstraZeneca AB [Member] January 15, 2018 [Member]	Dec. 31, 2013 AstraZeneca AB [Member] FDA Acceptance [Member]	Dec. 31, 2009 AstraZeneca AB [Member] Naloxegol (NKTR-118) and Naloxegol Fixed-dose Combination Program (NKTR-119) [Member] Upfront Payment Arrangement [Member]	Sep. 16, 2013 AstraZeneca AB [Member] Naloxegol [Member]	Dec. 31, 2013 AstraZeneca AB [Member] Naloxegol [Member]	Dec. 31, 2013 AstraZeneca AB [Member] Naloxegol [Member] Pre-approval Cardiovascular Safety Study Not Required [Member]	Dec. 31, 2013 AstraZeneca AB [Member] Naloxegol Fixed-dose Combination Program [Member]	Dec. 31, 2009 Roche [Member] License Extension Option [Member]	Dec. 31, 2013 Roche [Member] MIRCERA [Member]	Dec. 31, 2013 Roche [Member] MIRCERA [Member]	Feb. 29, 2012 Roche [Member] MIRCERA [Member] Performance-based Milestone Payments [Member]	Feb. 29, 2012 Roche [Member] MIRCERA [Member] Upfront Payment Arrangement [Member]	Dec. 31, 2013 Roche [Member] PEGASYS [Member]	Dec. 31, 2013 Roche [Member] PEGASYS and MIRCERA [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member]	Jun. 30, 2013 Bayer Healthcare LLC [Member]	Dec. 31, 2013 Bayer Healthcare LLC [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member] Performance-based Milestone Payments [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member] Upfront Payment Arrangement [Member]	Dec. 31, 2013 Affymax, Inc. [Member] OMONTYS [Member]	Dec. 31, 2010 Amgen, Inc. [Member]	Dec. 31, 2013 Amgen, Inc. [Member]	Dec. 31, 2013 Baxter Healthcare [Member] BAX 855 (Hemophilia) [Member]	Dec. 31, 2013 Baxter Healthcare [Member] BAX 855 (Hemophilia) [Member] Upfront Payment Arrangement [Member]	Dec. 31, 2013 Other Member [Member]
Deferred Revenue Arrangement [Line Items]
Potential future additional payments for development milestones	$ 144.3																							$ 50.0						$ 28.0		$ 66.3
Received upfront and milestone payments										125.0					31.0			22.0	5.0						20.0	40.0		50.0			4.0
Contingent payments receivable based on development events regulatory to be pursued and completed solely by others			140.0						70.0			175.0	35.0	75.0
Development milestones achieved		25.0																					10.0
Contingent repayments of payment received				70.0	10.0	10.0	20.0	30.0
Accrued interest rate				4.50%
Reduction on non-U.S. royalty for repayment											50.00%
Potential reduction in US royalty rate for repayment											2.00%
Maximum potential reduction in royalties											35.0
Deferred revenue																16.1	16.1			10.3	6.9			22.5					34.2
Expected consideration																	27.0
Consideration received for product delivered in 2013																18.6
Performance milestone payments recorded as a liability to Bayer																						10.0
Deferred revenue recognized																											$ 6.7

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 17,708	$ 16,199	$ 18,885
Cost of Goods Sold [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,297	1,496	1,266
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	7,910	7,082	7,944
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 8,501	$ 7,621	$ 9,675

Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs	$ 23.4
Recognized over a weighted-average period	1 year 8 months 12 days
Dividend yield	0.00%	0.00%	0.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield		0.00%
Weighted-average grant-date fair value	$ 4.95	$ 3.92	$ 5.22
Total intrinsic value of options exercised	4.5	1.9	3.7
Estimated fair value of options vested	$ 14.1	$ 15.7	$ 18.1
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit awards outstanding	0	120,580	136,080
Restricted stock unit awards granted	0	0	0

Stock-Based Compensation - Black-Scholes Option-Pricing Model Assumptions Used to Calculate Fair Value of Employee Stock Options (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Average risk-free interest rate	0.90%	0.90%	1.60%
Dividend yield	0.00%	0.00%	0.00%
Average volatility factor	61.20%	62.20%	63.80%
Average weighted average expected life	5 years 2 months 12 days	5 years	4 years 10 months 24 days

Stock-Based Compensation - Stock Option Activity Under Equity Incentive Plans (Detail) (Stock Options [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning balance	18,996
Number of Shares, Options granted	3,470
Number of Shares, Options exercised	(1,047)
Number of Shares, Options forfeited and canceled	(764)
Number of Shares, Outstanding, Ending balance	20,655
Number of Shares, Vested and Expected to Vest	20,357
Number of Shares, Exercisable	15,519
Weighted-Average Exercise Price per Share, Outstanding, Beginning balance	$ 9.03
Weighted-Average Exercise Price per Share, Options granted	$ 9.42
Weighted-Average Exercise Price per Share, Options exercised	$ 7.07
Weighted-Average Exercise Price per Share, Options forfeited and Canceled	$ 12.76
Weighted-Average Exercise Price per Share, Outstanding, Ending balance	$ 9.06
Weighted-Average Exercise Price per Share, Vested and expected to vest	$ 9.07
Weighted-Average Exercise Price per Share, Exercisable	$ 9.08
Weighted-Average Remaining Contractual Life, Outstanding	4 years 4 months 6 days
Weighted-Average Remaining Contractual Life, Vested and expected to Vest	4 years 3 months 22 days
Weighted-Average Remaining Contractual Life, Exercisable	3 years 7 months 21 days
Aggregate Intrinsic Value, Outstanding	$ 56,269
Aggregate Intrinsic Value, Vested and expected to Vest	55,454
Aggregate Intrinsic Value, Exercisable	$ 43,287

Income Taxes - Income (Loss) Before Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Domestic	$ (161,068)	$ (174,258)	$ (135,880)
Foreign	1,300	2,809	2,920
Loss before provision for income taxes	$ (159,768)	$ (171,449)	$ (132,960)

Income Taxes - Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:
Federal		$ (137)
State	1	1	1
Foreign	1,838	1,029	921
Total Current	1,839	893	922
Deferred:
Federal	422	(422)
State	49	(49)
Foreign	(65)	(16)	96
Total Deferred	406	(487)	96
Provision for income taxes	$ 2,245	$ 406	$ 1,018

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Statutory income tax rate	35.00%
Increase in valuation allowance	$ 51,800,000	$ 43,600,000
Valuation allowance related to stock-based compensation and exercises prior to the implementation of ASC 515 and 718	35,600,000	35,600,000
Deferred U.S. income taxes	422,000	(422,000)
Income taxes have not been provided on a cumulative total	1,700,000
Federal orphan drug credits	17,700,000
Federal orphan drug credits, expiration year	2026
Unrecognized tax benefits, period may increase or decrease due to tax examination	Next twelve months
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforward for income tax	1,029,700,000
Net operating loss carryforward, expiration year	2018
Income tax research credits	36,500,000
Income tax research credits, expiration year	2019
State [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforward for income tax	614,600,000
Net operating loss carryforward, expiration year	2014
Income tax research credits	$ 20,900,000

Income Taxes - Income Tax Provision Related to Continuing Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
U.S. federal provision (benefit)
At statutory rate	$ (55,919)	$ (60,007)	$ (46,536)
State taxes	50	(48)	1
Change in valuation allowance	55,042	47,349	48,959
Foreign tax inclusion		6,510
Non-cash interest expense on liability related to sale of future royalties	7,808	6,320
Foreign tax differential	(20)	(227)	(129)
Research credits	(6,273)	(591)	(893)
Other	1,557	1,100	(384)
Provision for income taxes	$ 2,245	$ 406	$ 1,018

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Net operating loss carryforwards	$ 391,385	$ 351,354
Research and other credits	61,707	52,769
Deferred revenue	35,588	39,521
Sale of future royalties	28,057	39,750
Stock-based compensation	25,962	23,746
Capitalized research expenses	17,687	7,192
Reserves and accruals	14,685	8,776
Property and equipment	8,580	8,482
Other	2,539	2,773
Deferred tax assets before valuation allowance	586,190	534,363
Valuation allowance for deferred tax assets	(586,040)	(534,268)
Total deferred tax assets	150	95
Total deferred tax liabilities
Net deferred tax assets	$ 150	$ 95

Income Taxes - Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Contingency [Line Items]
Beginning balance	$ 14,067	$ 13,576	$ 13,058
Reductions
Reductions
Settlements
Lapses in statute of limitations		(137)
Ending balance	16,363	14,067	13,576
Federal [Member]
Income Tax Contingency [Line Items]
Tax positions related to current year, Additions	477	289	297
Tax positions related to prior year, Additions	636	37
State [Member]
Income Tax Contingency [Line Items]
Tax positions related to current year, Additions	381	302	221
Foreign [Member]
Income Tax Contingency [Line Items]
Tax positions related to prior year, Additions	$ 802

Segment Reporting - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended		12 Months Ended
	Dec. 31, 2013 Segment	Dec. 31, 2012	Dec. 31, 2011 Roche [Member]	Dec. 31, 2011 UCB [Member]	Dec. 31, 2013 Revenue [Member] Roche [Member]	Dec. 31, 2012 Revenue [Member] Roche [Member]	Dec. 31, 2013 Revenue [Member] UCB [Member]	Dec. 31, 2012 Revenue [Member] UCB [Member]	Dec. 31, 2013 Revenue [Member] AstraZeneca [Member]	Dec. 31, 2013 Revenue [Member] Bayer [Member]	Dec. 31, 2012 Revenue [Member] Affymax, Inc. [Member]	Dec. 31, 2013 United States [Member]	Dec. 31, 2012 United States [Member]	Dec. 31, 2013 India [Member]	Dec. 31, 2012 India [Member]
Segment Reporting Information [Line Items]
Number of operating business segment	1
Number of components within business segment	2
Percentage revenue from clients			16.00%	27.00%	28.00%	23.00%	21.00%	30.00%	17.00%	10.00%	11.00%
Property and equipment, net	$ 66,974	$ 72,215										$ 57,300	$ 62,500	$ 7,700	$ 9,700
Percentage of net book value of property and equipment												88.00%	87.00%	12.00%	13.00%

Segment Reporting - Revenue by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue by geographic area
Total revenue	$ 31,146	$ 60,909	$ 33,862	$ 23,004	$ 21,146	$ 18,412	$ 23,684	$ 17,949	$ 148,921	$ 81,191	$ 71,480
Reportable Geographical Components [Member] \| United States [Member]
Revenue by geographic area
Total revenue									42,535	34,591	37,896
Reportable Geographical Components [Member] \| European [Member]
Revenue by geographic area
Total revenue									$ 106,386	$ 46,600	$ 33,584

Subsequent Event - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended		1 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2011 Common Shares [Member]	Jan. 24, 2011 Common Shares [Member]	Jan. 28, 2014 Subsequent Event [Member] Common Shares [Member]	Jan. 31, 2014 Subsequent Event [Member] Common Shares [Member]
Subsequent Event [Line Items]
Common stock, shares issued		116,494,000	115,259,000		19,000,000	9,775,000
Proceeds from sale of common stock	$ 219,783,000			$ 220,400,000		$ 117,200,000	$ 117,200,000
Legal, accounting fees, filing fees and other offering expenses				$ 600,000		$ 600,000	$ 600,000

Selected Quarterly Financial Data - Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Product sales	$ 8,040	$ 14,672	$ 10,324	$ 11,810	$ 10,405	$ 8,355	$ 9,694	$ 6,945	$ 44,846	$ 35,399	$ 24,864
Total revenue	31,146	60,909	33,862	23,004	21,146	18,412	23,684	17,949	148,921	81,191	71,480
Cost of goods sold	8,960	12,877	5,011	11,661	7,290	7,228	7,203	8,707	38,509	30,428	21,891
Research and development expenses	48,248	43,914	52,230	45,618	46,373	34,016	33,201	35,085	190,010	148,675	126,766
Operating loss	(35,894)	(6,525)	(32,605)	(45,106)	(43,381)	(32,900)	(26,988)	(37,932)	(120,130)	(141,201)	(123,937)
Net loss	$ (47,659)	$ (16,543)	$ (42,748)	$ (55,063)	$ (52,926)	$ (43,547)	$ (34,285)	$ (41,097)	$ (162,013)	$ (171,855)	$ (133,978)
Basic and diluted net loss per share	$ (0.41)	$ (0.14)	$ (0.37)	$ (0.48)	$ (0.46)	$ (0.38)	$ (0.30)	$ (0.36)	$ (1.40)	$ (1.50)	$ (1.19)

- Definition

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

+ References

+ Details

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References+ Details

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Statement Of Stockholders Equity [Abstract]
Stock issuance costs	$ 617

Consolidated Statements of Cash Flows (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Statement Of Cash Flows [Abstract]
Future royalties transaction costs	$ 4.4
Senior secured notes issuance costs	$ 4.5

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2013
Subsequent Events [Abstract]
Subsequent Event	Note 14 — Subsequent Event On January 28, 2014, we completed the issuance and sale of 9,775,000 shares of our common stock for gross proceeds to the Company of approximately $117.2 million. Additionally, we incurred approximately $0.6 million in legal and accounting fees, filing fees, and other offering expenses.