Organization and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2011
Organization and Summary of Significant 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 designed to improve the benefits of drugs for patients. *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 and Aerogen, Inc. All intercompany accounts and transactions have been eliminated in consolidation. On December 2, 2010, we completed the dissolution of Aerogen, Inc. and all remaining assets were transferred to Nektar Therapeutics. 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 income in the stockholders’ equity section of the Condensed Consolidated Balance Sheets. To date, such cumulative currency translation adjustments have not been material to our consolidated financial position. Revenue, expenses, assets, and liabilities can vary during each quarter of the year. The results and trends in these interim Condensed Consolidated Financial Statements may not be indicative of the results to be expected for the full year or any other periods. The accompanying Condensed Consolidated Balance Sheet as of June 30, 2011, the Condensed Consolidated Statements of Operations for the three and six months ended June 30, 2011 and 2010, and the Condensed Consolidated Statements of Cash Flows for the six months ended June 30, 2011 and 2010 are unaudited. The Condensed Consolidated Balance Sheet data as of December 31, 2010 was derived from the audited consolidated financial statements which are included in our Annual Report on Form 10-K filed with the SEC on March 1, 2011. 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, 2010. *Use of Estimates* The preparation of financial statements in conformity with U.S. 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 these estimates. On an ongoing basis, we evaluate our estimates, including those related to deferred revenue recognition periods, inventories, the impairment of investments and long-lived assets, restructuring and contingencies, stock-based compensation, and litigation, amongst others. 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 impact previously reported revenue, operating loss or net loss or total assets, liabilities or stockholders’ equity. *Segment Information* 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. *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, royalties, and other amounts due under collaborative research, development and commercialization agreements. 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 regularly review our customers’ payment histories and associated credit risk. We have not experienced significant credit losses from our accounts receivable and therefore recorded no allowance for doubtful accounts at both June 30, 2011 and December 31, 2010. 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 regulatory requirements. In certain cases, we rely on single sources of supply. Consequently, in the event that supplies are delayed or interrupted for any reason, our ability to develop and produce our products could be impaired, which could have a material adverse effect on our business, financial condition and results of operations. *Revenue* Product sales and royalties 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. Generally, we are entitled to royalties from our partners based on their net sales of approved drugs. We recognize royalty revenue when the cash is received or when the royalty amount to be received is estimable and collection is reasonably assured. License, collaboration and other We enter into license and manufacturing agreements and collaborative research, development and commercialization arrangements with pharmaceutical and biotechnology 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, 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 for each element. On January 1, 2011, we adopted on a prospective basis Accounting Standards Update (ASU) 2009-13, which amends the criteria to identify separate units of accounting within Subtopic 605-25, “Revenue Recognition-Multiple-Element Arrangements.” The adoption of the standard did not impact our financial position or results of operations as of and for the three and six months ended June 30, 2011 as we did not enter into or materially modify any multiple-element arrangements during that period. However, the adoption of this standard may result in revenue recognition patterns for future agreements that are materially different from those recognized for our existing multiple-element arrangements. Upfront fees received for license and collaborative agreements entered into prior to January 1, 2011 are recognized ratably over our expected performance period under the arrangement. Management makes its best estimate of the period over which we expect to fulfill our performance obligations, which may include technology transfer assistance, clinical development activities, and manufacturing activities from development through the commercialization of the product. Given the uncertainties of these collaborative arrangements, significant judgment is required to determine the duration of the performance period. On January 1, 2011, we elected to prospectively adopt ASU 2010-17, “Milestone Method of Revenue Recognition”. Under the milestone method, 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 more 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 on either 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 and approvals for drug candidates. As of January 1, 2011, our agreements with partners included potential future payments for development milestones totaling approximately $183.8 million. Given the challenges inherent in developing and obtaining approval for pharmaceutical and biologic products, there was substantial uncertainty whether any such milestones would be achieved at the time these licensing and collaboration agreements were entered into. In addition, we evaluated whether the development milestones met the remaining criteria to be considered substantive. As a result of our analysis, we consider our development milestones to be substantive and, accordingly, we expect to recognize as revenue future payments received from such milestones as each milestone is achieved. The election to adopt the milestone method did not impact our financial position or results of operations as of and for the three and six months ended June 30, 2011. However, this policy election may result in revenue recognition patterns for future milestones that are materially different from those recognized for milestones received prior to adoption. Milestone payments received prior to January 1, 2011 have been deferred and are recognized as revenue ratably over the period of time from the achievement of the milestone to our estimated date on which the next milestone will be achieved. Management makes its best estimate of the period of time until the next milestone is expected to be reached. Final milestone payments were recorded and recognized upon achieving the respective milestone. The Company will continue to recognize milestones payments received prior to January 1, 2011 in this manner. As of June 30, 2011, deferred revenue from milestone payments received prior to January 1, 2011 is not significant. Our license and collaboration agreements with certain partners also provide for contingent payments to us based solely upon the performance of our partner. For such contingent payments we expect to recognize the payments as revenue when they are earned under the applicable contract, 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 recognize such sales-based payments upon achievement of the milestone, provided that collection is reasonably assured. *Income Taxes* We account for income taxes under the liability method, in which 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. For the three months and six months ended June 30, 2011 and 2010, we recorded an income tax provision for our Nektar India operations at an effective tax rate of approximately 33% and 34%, respectively. 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.