Nektar Therapeutics (NKTR) 10-Q 1 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 24, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Trading Symbol	'NKTR	'
Entity Registrant Name	'NEKTAR THERAPEUTICS	'
Entity Central Index Key	'0000906709	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	127,301,902

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$30,699	$39,067
Short-term investments	245,737	197,959
Accounts receivable, net	3,047	2,229
Inventory	14,111	13,452
Other current assets	4,629	5,175
Total current assets	298,223	257,882
Restricted cash	25,000	25,000
Property and equipment, net	71,070	66,974
Goodwill	76,501	76,501
Other assets	7,343	8,170
Total assets	478,137	434,527
Current liabilities:	'	'
Accounts payable	7,437	9,115
Accrued compensation	11,386	14,254
Accrued expenses	5,814	6,243
Accrued clinical trial expenses	13,208	16,905
Interest payable	6,917	6,917
Deferred revenue, current portion	24,766	23,664
Other current liabilities	14,827	21,123
Total current liabilities	84,355	98,221
Senior secured notes	125,000	125,000
Capital lease obligations, less current portion	6,025	8,049
Liability related to receipt of refundable milestone payment	70,000	70,000
Liability related to sale of future royalties, less current portion	121,431	121,520
Deferred revenue, less current portion	88,918	82,384
Other long-term liabilities	17,768	19,256
Total liabilities	513,497	524,430
Commitments and contingencies	'	'
Stockholders' equity (deficit):	'	'
Preferred stock, $0.0001 par value; 10,000 shares authorized, no shares designated, issued or outstanding at June 30, 2014 or December 31, 2013, respectively	0	0
Common stock, $0.0001 par value; 300,000 authorized; 127,286 shares and 116,494 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	12	11
Capital in excess of par value	1,776,746	1,643,660
Accumulated other comprehensive loss	-887	-1,181
Accumulated deficit	-1,811,231	-1,732,393
Total stockholders' equity (deficit)	-35,360	-89,903
Total liabilities and stockholders' equity (deficit)	$478,137	$434,527

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.00	$0.00
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	$0.00	$0.00
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	127,286	116,494
Common stock, shares outstanding	127,286	116,494

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue:	'	'	'	'
Product sales and royalty revenue	$5,891	$10,675	$11,808	$22,810
Non-cash royalty revenue related to sale of future royalties	4,837	3,828	10,610	8,221
License, collaboration and other revenue	17,785	19,359	25,866	25,835
Total revenue	28,513	33,862	48,284	56,866
Operating costs and expenses:	'	'	'	'
Cost of goods sold	5,108	5,011	13,015	16,672
Research and development	36,702	52,230	75,040	97,848
General and administrative	9,619	9,226	19,547	20,057
Total operating costs and expenses	51,429	66,467	107,602	134,577
Loss from operations	-22,916	-32,605	-59,318	-77,711
Non-operating income (expense):	'	'	'	'
Interest income	132	209	266	523
Interest expense	-4,488	-4,656	-9,021	-9,301
Non-cash interest expense on liability related to sale of future royalties	-5,134	-5,485	-10,521	-11,028
Other income (expense), net	-36	-6	142	123
Total non-operating expense, net	-9,526	-9,938	-19,134	-19,683
Loss before provision for income taxes	-32,442	-42,543	-78,452	-97,394
Provision for income taxes	195	205	386	417
Net loss	($32,637)	($42,748)	($78,838)	($97,811)
Basic and diluted net loss per share	($0.26)	($0.37)	($0.63)	($0.85)
Weighted average shares outstanding used in computing basic and diluted net loss per share	127,040	115,544	125,301	115,427

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Comprehensive loss	($32,584)	($43,689)	($78,544)	($98,790)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:	'	'
Net loss	($78,838)	($97,811)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Non-cash royalty revenue related to sale of future royalties	-10,610	-8,221
Non-cash interest expense on liability related to sale of future royalties	10,521	11,028
Stock-based compensation	8,525	8,601
Depreciation and amortization	6,519	7,281
Other non-cash transactions	865	159
Changes in operating assets and liabilities:	'	'
Accounts receivable, net	-818	-236
Inventory	-659	-2,210
Other assets	738	5,508
Accounts payable	-1,818	2,631
Accrued compensation	-2,868	2,314
Accrued expenses	-314	3,280
Accrued clinical trial expenses	-3,697	-565
Interest payable	0	-166
Deferred revenue	7,636	-2,818
Other liabilities	-6,557	-1,223
Net cash used in operating activities	-71,375	-72,448
Cash flows from investing activities:	'	'
Maturities of investments	118,777	200,477
Purchases of investments	-166,496	-109,400
Purchases of property and equipment	-5,192	-794
Net cash (used in) provided by investing activities	-52,911	90,283
Cash flows from financing activities:	'	'
Payment of capital lease obligations	-1,650	-1,466
Repayment of proceeds from sale of future royalties	-7,000	-3,000
Issuance of common stock, net of issuance costs	116,601	0
Proceeds from shares issued under equity compensation plans	7,961	2,621
Net cash provided by (used in) financing activities	115,912	-1,845
Effect of exchange rates on cash and cash equivalents	6	5
Net (decrease) increase in cash and cash equivalents	-8,368	15,995
Cash and cash equivalents at beginning of period	39,067	25,437
Cash and cash equivalents at end of period	30,699	41,432
Supplemental disclosure of cash flow information:	'	'
Cash paid for interest	$8,622	$9,070

Organization_and_Summary_of_Si

Organization and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2014
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 ongoing investment to date and are expected to continue to require significant investment. 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 generated from licensing, collaboration and manufacturing agreements and financing transactions. At June 30, 2014, we had approximately $301.4 million in cash and investments in marketable securities, of which $25.0 million was restricted in relation to our 12% senior secured notes, and $159.8 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 4, this royalty obligation liability will not be settled in cash.
	Basis of Presentation and Principles of Consolidation
	Our consolidated financial statements include the financial position, results of operations and cash flows of our wholly-owned subsidiaries: Nektar Therapeutics (India) Private Limited (Nektar India) and Nektar Therapeutics UK Limited. All intercompany accounts and transactions have been eliminated in consolidation.
	We prepared our Condensed Consolidated Financial Statements following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (GAAP) for annual periods can be condensed or omitted. In the opinion of management, these financial statements include all normal and recurring adjustments that we consider necessary for the fair presentation of our financial position and operating results.
	Our Condensed 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 loss in the stockholders’ equity (deficit) section of the Condensed Consolidated Balance Sheets. To date, such cumulative currency translation adjustments have not been significant to our consolidated financial position.
	Our comprehensive loss consists of our net loss plus our foreign currency translation gains and losses and unrealized holding gains and losses on available-for-sale securities, neither of which were significant during the three and six month periods ended June 30, 2014 and 2013. In addition, there were no significant reclassifications out of accumulated other comprehensive loss to the statements of operations during the three and six month periods ended June 30, 2014 and 2013.
	The accompanying Condensed Consolidated Financial Statements are unaudited. The Condensed Consolidated Balance Sheet data as of December 31, 2013 was derived from the audited consolidated financial statements which are included in our Annual Report on Form 10-K for the year ended December 31, 2013 filed with the SEC on February 27, 2014. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and the accompanying notes to those financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2013.
	Revenue, expenses, assets, and liabilities can vary during each quarter of the year. The results and trends in these interim Condensed Consolidated Financial Statements are not necessarily indicative of the results to be expected for the full year or any other periods.
	Use of Estimates
	The preparation of financial statements in conformity with 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 revenue and expenses during the reporting period. Actual results could differ materially from those estimates and assumptions. On an ongoing basis, we evaluate our estimates, including those related to deferred revenue recognition periods, inventory, the impairment of investments, the impairment of goodwill and long-lived assets, contingencies, accrued clinical trial expenses, estimated interest expense from our liability related to our sale of future royalties, stock-based compensation, and ongoing litigation, among other estimates. We base our estimates on historical experience and on other
	assumptions that management believes are reasonable under the circumstances. These estimates 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 revenue, operating loss, net loss, total assets, liabilities or stockholders’ equity (deficit).
	Segment Information
	We operate in one business segment which focuses on applying our technology platforms to improve the performance of established and novel drug candidates. 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.
	Significant 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 and our allowance for doubtful accounts was not significant at either June 30, 2014 or December 31, 2013.
	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.
	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 revenue
	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 in Note 4, 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 revenue
	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 our performance or on the occurrence of a specific outcome resulting from our 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 us. 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, obtaining regulatory approvals for and achieving commercial launches of drug products, 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 evaluate 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.
	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.
	Income Taxes
	For the three and six month periods ended June 30, 2014 and 2013, we recorded an income tax provision for our Nektar India operations at effective tax rates of approximately 34%. The U.S. federal deferred tax assets generated from our net operating losses have been fully reserved, as we believe it is not more likely than not that the benefit will be realized.
	Recently Issued Accounting Pronouncements
	In May 2014, the FASB issued guidance codified in ASC 606, Revenue Recognition — Revenue from Contracts with Customers, which amends the guidance in former ASC 605, Revenue Recognition, and is effective for public companies for fiscal years beginning after December 15, 2016. We are currently evaluating the impact of the provisions of ASC 606.

Cash_and_Investments_in_Market

Cash and Investments in Marketable Securities	6 Months Ended
	Jun. 30, 2014
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
		June 30,				December 31,
		2014				2013
	Cash and cash equivalents	$	30,699			$	39,067
	Short-term investments		245,737				197,959
	Restricted cash		25,000				25,000
	Total cash and investments in marketable securities	$	301,436			$	262,026
	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. 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. As of June 30, 2014 and December 31, 2013, all of our investments had maturities of one year or less.
	Gross unrealized gains and losses were not significant at either June 30, 2014 or December 31, 2013. During the three and six month periods ended June 30, 2014 and 2013, we did not sell any of our available-for-sale securities.
	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.
	Our portfolio of cash and investments in marketable securities includes (in thousands):
				Estimated Fair Value at
		Fair Value		June 30,				December 31,
		Hierarchy		2014				2013
		Level
	Corporate notes and bonds	2		$	171,793			$	138,515
	Corporate commercial paper	2			75,643				59,444
	Available-for-sale investments				247,436				197,959
	Money market funds	1			23,733				26,453
	Cash, including restricted cash	N/A			30,267				37,614
	Total cash and investments in marketable securities			$	301,436			$	262,026
	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. The disclosed fair value related to our 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. During the three and six month periods ended June 30, 2014 and 2013, there were no transfers between Level 1 and Level 2 of the fair value hierarchy.
	Additionally, as of June 30, 2014, 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.

Inventory

Inventory	6 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
Inventory	'
	Note 3 — Inventory
	Inventory consists of the following (in thousands):
		June 30,		December 31,
		2014		2013
	Raw materials	$	1,719	$	3,947
	Work-in-process		10,385		6,146
	Finished goods		2,007		3,359
	Total inventory	$	14,111	$	13,452
	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.

Liability_Related_to_Sale_of_F

Liability Related to Sale of Future Royalties	6 Months Ended
	Jun. 30, 2014
Text Block [Abstract]	'
Liability Related to Sale of Future Royalties	'
	Note 4 — 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 our license, manufacturing and supply agreement with UCB Pharma (UCB), and (b) MIRCERA®, under our 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. 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. We 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 as royalties from the CIMZIA® and MIRCERA® products are remitted directly to RPI. During the six months ended June 30, 2014 and 2013, we recognized $10.6 million and $8.2 million, respectively, in aggregate royalties from net sales of CIMZIA® and MIRCERA®.
	Since its inception, our estimate of the total interest expense on the Royalty Obligation 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.
	Pursuant to the Purchase and Sale Agreement, in March 2014 and March 2013, we were required to pay RPI $7.0 million and $3.0 million, respectively, as a result of worldwide net sales of MIRCERA® for the 12 month periods ended on December 31, 2013 and 2012 not reaching certain minimum thresholds. As of June 30, 2014, we do not expect to make any further payments related to the Purchase and Sale Agreement.
	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

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Note 5 — Commitments and Contingencies
	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, it could have a material adverse impact on the results of our operations of that period and on our cash flows and liquidity.
	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, 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. The term of these indemnification obligations is generally perpetual any time after execution of the agreement. There is generally no limitation on the potential amount of future payments we could be required to make under these indemnification obligations.
	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.
	To date, we have not incurred costs to defend lawsuits or settle claims related to these 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 in our Condensed Consolidated Balance Sheets at either June 30, 2014 or December 31, 2013.

Stockholders_Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2014
Equity [Abstract]	'
Stockholders' Equity	'
	Note 6 — Stockholders’ Equity
	On January 28, 2014, we completed the issuance and sale of 9,775,000 shares of our common stock in a public offering with total proceeds to the Company of approximately $117.2 million after deducting the underwriting commissions and discounts of approximately $7.5 million. Additionally, we incurred approximately $0.6 million in legal and accounting fees, filing fees, and other costs in connection with this offering.

License_and_Collaboration_Agre

License and Collaboration Agreements	6 Months Ended
	Jun. 30, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'
License and Collaboration Agreements	'
	Note 7 — License and Collaboration Agreements
	We have entered into various collaboration agreements including license agreements and collaborative research, manufacturing, development and commercialization agreements with various pharmaceutical and biotechnology companies. Under these collaboration agreements, 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 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):
			Three months ended				Six months ended
			June 30,				June 30,
	Partner	Drug or Drug Candidate	2014		2013		2014		2013
	Roche	PEGASYS® and MIRCERA®	$	3,219	$	2,625	$	6,415	$	5,250
	Bayer Healthcare LLC	BAY41-6551 (Amikacin Inhale)		2,393		13,111		3,146		13,825
	Amgen, Inc.	Neulasta®		1,250		1,250		2,500		2,535
	Baxter Healthcare	BAX 855 (Hemophilia)		669		597		1,006		1,297
	Other			10,254		1,776		12,799		2,928
	License, collaboration, and other revenue		$	17,785	$	19,359	$	25,866	$	25,835
	As of June 30, 2014, our collaboration agreements include potential aggregate future payments for development milestones of approximately $146.3 million, including the milestone amounts from our collaboration agreements with Bayer and Baxter described below. In addition, we are entitled to receive up to $175.0 million and $75.0 million of contingent payments related to the MOVANTIKTM (previously referred to as naloxegol and NKTR-118) and MOVANTIKTM fixed-dose combination (previously referred to as NKTR-119) drug development programs, respectively, based on development and regulatory events to be pursued and completed solely by AstraZeneca.
	There have been no material changes to our collaboration agreements in the three or six months ended June 30, 2014, except as described below.
	AstraZeneca AB: MOVANTIKTM (naloxegol oxalate), previously referred to as naloxegol and NKTR-118, and MOVANTIKTM fixed-dose combination program, previously referred to as 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 MOVANTIKTM and MOVANTIKTM fixed-dose combination program. AstraZeneca is responsible for all costs associated with research, development and commercialization and is responsible for all drug development and commercialization decisions for MOVANTIKTM and the MOVANTIKTM fixed-dose combination program. As of June 30, 2014, we are entitled to receive up to an additional $175.0 million and $75.0 million of contingent payments related to MOVANTIKTM and the MOVANTIKTM 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 MOVANTIKTM regulatory approval application filed in August 2013. As a result, we were entitled to a $25.0 million payment from AstraZeneca, which was received and fully recognized as revenue in September 2013.
	On September 16, 2013, AstraZeneca filed a New Drug Application (NDA) with the United States Food and Drug Administration (FDA) for MOVANTIKTM, 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 Condensed Consolidated Balance Sheet at June 30, 2014. If the FDA does not require a future clinical trial or other significant studies to assess the cardiovascular safety (CV Safety Study) of MOVANTIKTM 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 prior to an approval decision and AstraZeneca elects to terminate the license agreement in its entirety due to a CV Safety Study, we would be required to repay the $70.0 million payment plus accrued interest at an interest rate of 4.5% per annum, 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 accrued interest at an interest rate of 4.5% per annum, compounded annually. If the FDA requires a post-approval cardiovascular safety study as a condition to regulatory approval, then the royalty rate payable to us from net sales of MOVANTIKTM in the U.S. by AstraZeneca would be reduced by up to two percentage points to fund 33% of the external costs actually incurred by AstraZeneca to fund such post approval study subject to a $35.0 million aggregate cap.
	We will be entitled to the remaining $140.0 million of contingent payments if MOVANTIKTM 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 MOVANTIKTM and MOVANTIKTM 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 of June 30, 2014, we have deferred revenue of approximately $7.7 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. As of June 30, 2014, we have deferred revenue of approximately $13.4 million related to this agreement, 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 June 30, 2014, we have deferred revenue of approximately $5.7 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. In April 2013, Bayer initiated a Phase 3 clinical trial in the treatment of intubated and mechanically ventilated patients with Gram-negative pneumonia. As of June 30, 2014, we have received an upfront payment of $40.0 million in 2007 and milestone payments totaling $30.0 million. In addition, in June 2013, we made a $10.0 million payment to Bayer for the reimbursement of its costs of the Phase 3 clinical trial.
	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 June 30, 2014, we have deferred revenue of approximately $21.6 million related to this agreement, which we expect to recognize through December 2026, the estimated end of our obligations under this agreement.
	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. As of June 30, 2014, we have deferred revenue of approximately $31.7 million related to this agreement, which we expect to recognize through October 2020, the estimated end of our obligations under this agreement.
	Baxter Healthcare: 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 this agreement, 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. As of June 30, 2014, we do not have significant deferred revenue related to this agreement.
	Ophthotech Corporation: Fovista®
	We are a party to an agreement with Ophthotech Corporation (Ophthotech), dated September 30, 2006, under which Ophthotech received a worldwide, exclusive license to certain of our proprietary PEGylation technology to develop, manufacture and sell Fovista®. Under the terms of our agreement, we are the exclusive supplier of all of Ophthotech’s clinical and commercial requirements for our proprietary PEGylation reagent used in Fovista®. On May 19, 2014, Ophthotech entered into a Licensing and Commercialization Agreement with Novartis Pharma AG for Fovista®. Under our agreement with Ophthotech, we were entitled to a $19.75 million payment in connection with this licensing agreement, which was received in June 2014. As of June 30, 2014, we have deferred revenue of approximately $19.6 million related to this agreement, which we expect to recognize through March 2028, the estimated end of our obligations under our agreement with Ophthotech.
	In addition, we are entitled to up to $9.5 million in additional payments based upon Ophthotech’s potential achievement of certain regulatory and sales milestones. We are also entitled to low- to mid- single-digit royalties on net sales of Fovista® that vary based on sales levels. Our right to receive royalties in any particular country will expire upon the later of ten years after the first commercial sale of Fovista® or expiration of patent rights in such country.
	Other
	During the three months ended June 30, 2014, two of our collaboration partners achieved the successful transfer of our commercial manufacturing process in connection with the PEGylation materials used in their products. In connection with our assistance with these manufacturing technology transfers, we received a total of $9.0 million of milestone payments. We concluded that these payments are substantive milestones and recognized them in their entirety in the three months ended June 30, 2014.
	In addition, we have a number of collaboration agreements, including agreements with our collaboration partners UCB and Regado Biosciences, Inc., under which we are entitled to up to a total of $61.8 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.

StockBased_Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	Note 8 — Stock-Based Compensation
	Total stock-based compensation expense was recognized in our Condensed Consolidated Statements of Operations as follows (in thousands):
		Three months ended				Six months ended
		June 30,				June 30,
		2014		2013		2014		2013
	Cost of goods sold	$	280	$	324	$	599	$	647
	Research and development expense		1,832		1,977		3,805		3,852
	General and administrative expense		2,052		2,055		4,121		4,102
	Total stock-based compensation	$	4,164	$	4,356	$	8,525	$	8,601
	During the three months ended June 30, 2014 and 2013, we granted 642,860 and 162,080 stock options, respectively, at a weighted average grant-date fair value of $5.24 per share and $5.23 per share, respectively.
	During the six months ended June 30, 2014 and 2013, we granted 3,776,040 and 2,989,310 stock options, respectively, at a weighted average grant-date fair value of $5.84 per share and $4.63 per share, respectively.
	As a result of stock issuances under our equity compensation plans, during the three months ended June 30, 2014 and 2013, we issued 350,513 and 222,012 common shares, respectively, and during the six months ended June 30, 2014 and 2013, we issued 1,017,887 and 424,214 common shares, respectively.

Net_Loss_Per_Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Net Loss Per Share	'
	Note 9 — 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 accompanying Condensed 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 for the three months ended June 30, 2014 and 2013 consisted of approximately 10.6 million and 13.3 million, respectively, of stock options, and for the six months ended June 30, 2014 and 2013 consisted of approximately 9.8 million and 13.0 million, respectively, of stock options.

Organization_and_Summary_of_Si1

Organization and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Organization	'
	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 ongoing investment to date and are expected to continue to require significant investment. 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 generated from licensing, collaboration and manufacturing agreements and financing transactions. At June 30, 2014, we had approximately $301.4 million in cash and investments in marketable securities, of which $25.0 million was restricted in relation to our 12% senior secured notes, and $159.8 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 4, this royalty obligation liability will not be settled in cash.
Basis of Presentation and Principles of Consolidation	'
	Basis of Presentation and Principles of Consolidation
	Our consolidated financial statements include the financial position, results of operations and cash flows of our wholly-owned subsidiaries: Nektar Therapeutics (India) Private Limited (Nektar India) and Nektar Therapeutics UK Limited. All intercompany accounts and transactions have been eliminated in consolidation.
	We prepared our Condensed Consolidated Financial Statements following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (GAAP) for annual periods can be condensed or omitted. In the opinion of management, these financial statements include all normal and recurring adjustments that we consider necessary for the fair presentation of our financial position and operating results.
	Our Condensed 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 loss in the stockholders’ equity (deficit) section of the Condensed Consolidated Balance Sheets. To date, such cumulative currency translation adjustments have not been significant to our consolidated financial position.
	Our comprehensive loss consists of our net loss plus our foreign currency translation gains and losses and unrealized holding gains and losses on available-for-sale securities, neither of which were significant during the three and six month periods ended June 30, 2014 and 2013. In addition, there were no significant reclassifications out of accumulated other comprehensive loss to the statements of operations during the three and six month periods ended June 30, 2014 and 2013.
	The accompanying Condensed Consolidated Financial Statements are unaudited. The Condensed Consolidated Balance Sheet data as of December 31, 2013 was derived from the audited consolidated financial statements which are included in our Annual Report on Form 10-K for the year ended December 31, 2013 filed with the SEC on February 27, 2014. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and the accompanying notes to those financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2013.
	Revenue, expenses, assets, and liabilities can vary during each quarter of the year. The results and trends in these interim Condensed Consolidated Financial Statements are not necessarily indicative of the results to be expected for the full year or any other periods.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with 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 revenue and expenses during the reporting period. Actual results could differ materially from those estimates and assumptions. On an ongoing basis, we evaluate our estimates, including those related to deferred revenue recognition periods, inventory, the impairment of investments, the impairment of goodwill and long-lived assets, contingencies, accrued clinical trial expenses, estimated interest expense from our liability related to our sale of future royalties, stock-based compensation, and ongoing litigation, among other estimates. We base our estimates on historical experience and on other
	assumptions that management believes are reasonable under the circumstances. These estimates 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	'
	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 revenue, operating loss, net loss, total assets, liabilities or stockholders’ equity (deficit).
Segment Information	'
	Segment Information
	We operate in one business segment which focuses on applying our technology platforms to improve the performance of established and novel drug candidates. 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.
Significant Concentrations	'
	Significant 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 and our allowance for doubtful accounts was not significant at either June 30, 2014 or December 31, 2013.
	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.
Revenue Recognition	'
	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 revenue
	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 in Note 4, 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 revenue
	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 our performance or on the occurrence of a specific outcome resulting from our 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 us. 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, obtaining regulatory approvals for and achieving commercial launches of drug products, 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 evaluate 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.
Research and Development Expense	'
	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.
Income Taxes	'
	Income Taxes
	For the three and six month periods ended June 30, 2014 and 2013, we recorded an income tax provision for our Nektar India operations at effective tax rates of approximately 34%. The U.S. federal deferred tax assets generated from our net operating losses have been fully reserved, as we believe it is not more likely than not that the benefit will be realized.
Recently Issued Accounting Pronouncements	'
	Recently Issued Accounting Pronouncements
	In May 2014, the FASB issued guidance codified in ASC 606, Revenue Recognition — Revenue from Contracts with Customers, which amends the guidance in former ASC 605, Revenue Recognition, and is effective for public companies for fiscal years beginning after December 15, 2016. We are currently evaluating the impact of the provisions of ASC 606.

Cash_and_Investments_in_Market1

Cash and Investments in Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2014
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
		June 30,				December 31,
		2014				2013
	Cash and cash equivalents	$	30,699			$	39,067
	Short-term investments		245,737				197,959
	Restricted cash		25,000				25,000
	Total cash and investments in marketable securities	$	301,436			$	262,026
Portfolio of Cash and Investments in Marketable Securities	'
	Our portfolio of cash and investments in marketable securities includes (in thousands):
				Estimated Fair Value at
		Fair Value		June 30,				December 31,
		Hierarchy		2014				2013
		Level
	Corporate notes and bonds	2		$	171,793			$	138,515
	Corporate commercial paper	2			75,643				59,444
	Available-for-sale investments				247,436				197,959
	Money market funds	1			23,733				26,453
	Cash, including restricted cash	N/A			30,267				37,614
	Total cash and investments in marketable securities			$	301,436			$	262,026

Inventory_Tables

Inventory (Tables)	6 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
Inventory	'
	Inventory consists of the following (in thousands):
		June 30,		December 31,
		2014		2013
	Raw materials	$	1,719	$	3,947
	Work-in-process		10,385		6,146
	Finished goods		2,007		3,359
	Total inventory	$	14,111	$	13,452

License_and_Collaboration_Agre1

License and Collaboration Agreements (Tables)	6 Months Ended
	Jun. 30, 2014
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):
			Three months ended				Six months ended
			June 30,				June 30,
	Partner	Drug or Drug Candidate	2014		2013		2014		2013
	Roche	PEGASYS® and MIRCERA®	$	3,219	$	2,625	$	6,415	$	5,250
	Bayer Healthcare LLC	BAY41-6551 (Amikacin Inhale)		2,393		13,111		3,146		13,825
	Amgen, Inc.	Neulasta®		1,250		1,250		2,500		2,535
	Baxter Healthcare	BAX 855 (Hemophilia)		669		597		1,006		1,297
	Other			10,254		1,776		12,799		2,928
	License, collaboration, and other revenue		$	17,785	$	19,359	$	25,866	$	25,835

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation Expense	'
	Total stock-based compensation expense was recognized in our Condensed Consolidated Statements of Operations as follows (in thousands):
		Three months ended				Six months ended
		June 30,				June 30,
		2014		2013		2014		2013
	Cost of goods sold	$	280	$	324	$	599	$	647
	Research and development expense		1,832		1,977		3,805		3,852
	General and administrative expense		2,052		2,055		4,121		4,102
	Total stock-based compensation	$	4,164	$	4,356	$	8,525	$	8,601

Organization_and_Summary_of_Si2

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
			Segment
Organization And Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Cash and investments in marketable securities	$301,436,000	'	$301,436,000	'	$262,026,000
Indebtedness	159,800,000	'	159,800,000	'	'
Senior secured notes, issued	125,000,000	'	125,000,000	'	125,000,000
Restricted cash	25,000,000	'	25,000,000	'	25,000,000
Number of business segments	'	'	1	'	'
Effective income tax rates	34.00%	34.00%	34.00%	34.00%	'
12% Senior Secured Notes Due July 2017 [Member]	'	'	'	'	'
Organization And Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Senior secured notes, interest rate	12.00%	'	12.00%	'	'
Maturity date of senior secured notes	'	'	15-Jul-17	'	'
Restricted cash	$25,000,000	'	$25,000,000	'	'

Cash_and_Investments_in_Market2

Cash and Investments in Marketable Securities - Cash and Investments in Marketable Securities, Including Cash Equivalents and Restricted Cash (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash Cash Equivalents And Available For Sale Investments [Abstract]	'	'	'	'
Cash and cash equivalents	$30,699	$39,067	$41,432	$25,437
Short-term investments	245,737	197,959	'	'
Restricted cash	25,000	25,000	'	'
Total cash and investments in marketable securities	$301,436	$262,026	'	'

Cash_and_Investments_in_Market3

Cash and Investments in Marketable Securities - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Cash and Investments in Marketable Securities [Line Items]	'	'	'	'	'
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	$0	$0	$0	$0	'
Restricted cash	25,000,000	'	25,000,000	'	25,000,000
Level 1 to level 2 transfers	0	0	0	0	'
Level 2 to level 1 transfers	0	0	0	0	'
Senior secured notes carrying amount	125,000,000	'	125,000,000	'	125,000,000
12% Senior Secured Notes Due July 2017 [Member]	'	'	'	'	'
Cash and Investments in Marketable Securities [Line Items]	'	'	'	'	'
Restricted cash	$25,000,000	'	$25,000,000	'	'
Senior secured notes, interest rate	12.00%	'	12.00%	'	'
Senior secured notes, maturity date	'	'	15-Jul-17	'	'

Cash_and_Investments_in_Market4

Cash and Investments in Marketable Securities - Portfolio of Cash and Investments in Marketable Securities (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale investments	$247,436	$197,959
Cash, including restricted cash	30,267	37,614
Total cash and investments in marketable securities	301,436	262,026
Corporate Notes and Bonds [Member] | Fair Value Hierarchy Level 2 [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale investments	171,793	138,515
Corporate Commercial Paper [Member] | Fair Value Hierarchy Level 2 [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale investments	75,643	59,444
Money Market Funds [Member] | Fair Value Hierarchy Level 1 [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Money market funds	$23,733	$26,453

Inventory_Inventory_Detail

Inventory - Inventory (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Raw materials	$1,719	$3,947
Work-in-process	10,385	6,146
Finished goods	2,007	3,359
Total inventory	$14,111	$13,452

Liability_Related_to_Sale_of_F1

Liability Related to Sale of Future Royalties - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		1 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2013	Mar. 31, 2014	Feb. 24, 2012
					Milestone Scenario One [Member]	Milestone Scenario Two [Member]	Purchase and Sale Agreement with RPI [Member]
Liability Related to Sale of Future Royalties [Line Items]	'	'	'	'	'	'	'
Proceeds from sale of royalty rights	'	'	'	'	'	'	$124,000,000
Non-cash royalty revenue	4,837,000	3,828,000	10,610,000	8,221,000	'	'	'
Annual interest rate	'	'	0.17	'	'	'	'
Payment made for milestone not achieved year one	'	'	'	'	3,000,000	'	'
Payment made for milestone not achieved year two	'	'	'	'	'	$7,000,000	'
Royalty agreement contingent payment description	'	'	'As a result of worldwide net sales of MIRCERAfor the 12 month periods ended on December 31, 2013 and 2012 not reaching certain minimum thresholds	'	'	'	'

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (Indemnification Obligation [Member], USD $)	Jun. 30, 2014	Dec. 31, 2013
Indemnification Obligation [Member]	'	'
Loss Contingencies [Line Items]	'	'
Indemnification Obligations, liabilities	$0	$0

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jan. 28, 2014	Jan. 28, 2014
In Millions, except Share data in Thousands, unless otherwise specified			Common Shares [Member]	Common Shares [Member]
Class of Stock [Line Items]	'	'	'	'
Common stock, shares issued	127,286	116,494	'	9,775
Proceeds from sale of common stock	'	'	$117.20	'
Legal, accounting fees, filing fees and other costs	'	'	0.6	'
Underwriting commission and discounts	'	'	$7.50	'

License_and_Collaboration_Agre2

License and Collaboration Agreements - License, Collaboration and Other Revenue (Detail) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	$17,785	$19,359	$25,866	$25,835
Bayer Healthcare LLC [Member] | BAY41-6551 (Amikacin Inhale) [Member]	'	'	'	'
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	2,393	13,111	3,146	13,825
Roche [Member] | PEGASYS and MIRCERA [Member]	'	'	'	'
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	3,219	2,625	6,415	5,250
Amgen, Inc. [Member] | Neulasta [Member]	'	'	'	'
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	1,250	1,250	2,500	2,535
Baxter Healthcare [Member] | BAX 855 (Hemophilia) [Member]	'	'	'	'
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	669	597	1,006	1,297
Other [Member]	'	'	'	'
License And Collaboration Agreements [Line Items]	'	'	'	'
License, collaboration and other revenue	$10,254	$1,776	$12,799	$2,928

License_and_Collaboration_Agre3

License and Collaboration Agreements - Additional Information (Detail) (USD $)

6 Months Ended

0 Months Ended

6 Months Ended

1 Months Ended

2 Months Ended

6 Months Ended

1 Months Ended

6 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

In Millions, unless otherwise specified

Jun. 30, 2014

Sep. 25, 2013

Jun. 30, 2014

Jun. 30, 2014

Feb. 29, 2012

Feb. 29, 2012

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2007

Sep. 16, 2013

Sep. 16, 2013

Sep. 16, 2013

Sep. 16, 2013

Sep. 16, 2013

Sep. 16, 2013

Sep. 16, 2013

Jun. 30, 2014

Sep. 16, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

MOVANTIK [Member]

MOVANTIK [Member]

Roche [Member]

Roche [Member]

Roche [Member]

Roche [Member]

Roche [Member]

Baxter Healthcare [Member]

Amgen, Inc. [Member]

Bayer Healthcare LLC [Member]

Bayer Healthcare LLC [Member]

Bayer Healthcare LLC [Member]

Bayer Healthcare LLC [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

AstraZeneca AB [Member]

Ophthotech Corporation [Member]

Other [Member]

Other [Member]

US and EU Commercial Launch [Member]

MIRCERA [Member]

MIRCERA [Member]

MIRCERA [Member]

PEGASYS [Member]

PEGASYS and MIRCERA [Member]

BAX 855 (Hemophilia) [Member]

Performance-based Milestone Payments [Member]

Upfront Payment Arrangement in 2007 [Member]

January 15, 2015 [Member]

January 15, 2016 [Member]

January 15, 2017 [Member]

January 15, 2018 [Member]

MOVANTIK [Member]

MOVANTIK [Member]

MOVANTIK [Member]

MOVANTIK [Member]

Movantik Fixed-dose Combination Program [Member]

Fovista [Member]

Performance-based Milestone Payments [Member]

Upfront Payment Arrangement in 2007 [Member]

Pre-approval Cardiovascular Safety Study Not Required [Member]

Deferred Revenue Arrangement [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Potential aggregate future additional payments for development milestones

$146.30

'

'

'

'

'

'

'

$28

'

'

$50

'

'

'

'

'

'

'

'

'

'

'

'

'

$9.50

'

$61.80

Contingent payments receivable based on development events regulatory to be pursued and completed solely by others

'

'

140

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

175

'

35

75

'

'

'

Contingent payments received

'

25

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contingent repayments of payment received

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

70

10

10

20

30

'

'

'

'

'

'

'

'

Accrued interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.045

'

'

'

'

'

'

'

'

'

'

'

'

'

Reduction on non-U.S. royalty for repayment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

'

'

'

'

'

'

'

Potential reduction in US royalty rate for repayment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.00%

'

'

'

'

'

'

'

Percentage of post approval study costs to repay

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

33.00%

'

'

'

'

'

'

'

Maximum potential reduction in royalties

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35

'

'

'

'

'

Deferred revenue

'

'

'

13.4

'

'

7.7

5.7

0

31.7

'

21.6

'

'

'

'

'

'

'

'

'

'

'

'

'

19.6

'

'

Received upfront and milestone payments

'

'

'

'

22

5

'

'

'

'

'

'

30

40

'

'

'

'

'

'

'

'

'

'

'

19.75

'

'

Consideration received for product delivered in 2013

'

'

'

18.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Performance milestone payment to Bayer

'

'

'

'

'

'

'

'

'

'

10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Royalty expiration period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

Milestone payment received from transfers of manufacturing technology

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$9

'

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]	'	'	'	'
Total stock-based compensation	$4,164	$4,356	$8,525	$8,601
Cost of Goods Sold [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]	'	'	'	'
Total stock-based compensation	280	324	599	647
Research and development expense [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]	'	'	'	'
Total stock-based compensation	1,832	1,977	3,805	3,852
General and Administrative Expense [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]	'	'	'	'
Total stock-based compensation	$2,052	$2,055	$4,121	$4,102

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Common Shares [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock issuances under equity compensation plans	350,513	222,012	1,017,887	424,214
Stock Options [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Granted stock options	642,860	162,080	3,776,040	2,989,310
Weighted average grant-date fair value	5.24	5.23	5.84	4.63

Net_Loss_Per_Share_Additional_

Net Loss Per Share - Additional Information (Detail) (Stock Options [Member])	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
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	10.6	13.3	9.8	13