We have entered into various collaboration agreements including license agreements and collaborative research, development and commercialization agreements with various pharmaceutical and biotechnology companies. Under these collaboration arrangements, we are entitled to receive license fees, upfront payments, milestone and other contingent payments, royalties, sales milestone payments, and payments for the manufacture and supply of our proprietary PEGylation materials and/or reimbursement for research and development activities. All of our collaboration agreements are generally cancelable by our partners without significant financial penalty. Our costs of performing these services are generally included in research and development expense, except that costs for product sales to our collaboration partners are included in cost of goods sold. We analyze our agreements to determine whether we should account for the agreements within the scope of ASC 808, Collaborative Arrangements, and, if so, we analyze whether we should account for any elements under the relevant revenue recognition guidance or whether we should record the reimbursements from our partner as contra research and development expense. As described in Note 1, on January 1, 2018, we adopted ASC 606, Revenue Recognition - Revenue from Contracts with Customers, which supersedes the guidance in ASC 605, Revenue Recognition. We recognized revenue under ASC 606 for the year ended December 31, 2018 and under ASC 605 for the years ended December 31, 2017 and 2016. In the year ended December 31, 2018, we recognized $95.3 million of revenue for performance obligations that we had satisfied in prior periods. This amount includes all of our royalty revenue, non-cash royalty revenue and the $10.0 million ADYNOVATE^® sales milestone because these revenues substantially relate to the licenses that we had previously granted. This amount also includes the $10.0 million development milestone payment earned from Baxalta described below.

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

		Year Ended December 31,
Partner	Agreement	2018		2017		2016
Bristol-Myers Squibb	NKTR-214	$	1,059,768	$	—		—
Baxalta Incorporated / Takeda	Hemophilia, including ADYNOVATE^® and ADYNOVI^TM		20,328		11,443		650
Eli Lilly and Company	NKTR-358		11,634		130,087		—
Amgen, Inc.	Neulasta^®		5,000		5,000		5,000
Ophthotech Corporation⁽¹⁾	Fovista^®		—		19,123		1,408
Bayer Healthcare LLC⁽¹⁾	BAY41-6551 (Amikacin Inhale)		—		17,931		1,429
AstraZeneca AB	MOVANTIK^®and MOVENTIG^®		—		4,600		33,000
Other			535		22,781		18,895
License, collaboration and other revenue		$	1,097,265	$	210,965	$	60,382

(1)	These collaboration agreements were completed as of December 31, 2017.

The following table presents the changes in our deferred revenue balance from our collaboration agreements during the year ended December 31, 2018 (in thousands):

	For the year ended December 31, 2018
Deferred revenue—December 31, 2017	$	37,970
Transition adjustment related to adoption of ASC 606		(1,953	)
Additions to deferred revenue		5,950
Recognition of previously unearned revenue		(17,331	)
Deferred revenue—December 31, 2018	$	24,636

Our balance of deferred revenue contains the transaction price from our collaboration agreements allocated to performance obligations which are partially unsatisfied. We expect to recognize approximately $13.9 million of our deferred revenue over the next twelve months and recognize approximately half of the remaining $10.7 million over the following twelve months.

As of December 31, 2018, our collaboration agreements with partners included potential future payments for development milestones totaling approximately $1.7 billion, including amounts from our agreements with BMS and Lilly described below. In addition, under our collaboration agreements we are entitled to receive other contingent payments, including contingent sales milestones and royalty payments, as described below.

On February 13, 2018, we entered into a Strategic Collaboration Agreement with BMS (BMS Collaboration Agreement) and Share Purchase Agreement, both of which became effective on April 3, 2018. Pursuant to these agreements, we and BMS will jointly develop NKTR-214, including, without limitation, in combination with BMS’s Opdivo^® (nivolumab) and Opdivo^® plus Yervoy^®(ipilimumab), and other compounds of BMS, us or any third party. The parties have agreed to jointly commercialize NKTR-214 on a worldwide basis. We retained the right to record all worldwide sales for NKTR-214. We will share global commercialization profits and losses with BMS for NKTR-214, with Nektar sharing 65% and BMS sharing 35% of the net profits and losses. The parties will share the internal and external development costs for NKTR-214 in combination regimens based on each party’s relative ownership interest in the compounds included in the regimens. In accordance with the agreement, the parties will share development costs for NKTR-214 in combination with Opdivo^®, 67.5% of costs to BMS and 32.5% to Nektar, and for NKTR-214 in a triplet combination with Opdivo^® and Yervoy^®, 78% of costs to BMS and 22% to Nektar. The parties will share costs for the production of NKTR-214, 35% of costs to BMS and 65% to Nektar.

The BMS Collaboration Agreement superseded and replaced the Clinical Trial Agreement we entered into with BMS in September 2016 to develop NKTR-214 in combination with Opdivo^®. Under the Clinical Trial Agreement, we acted as the sponsor of each Combination Therapy Trial and BMS was responsible for 50% of all out-of-pocket costs reasonably incurred in connection with third party contract research organizations, laboratories, clinical sites and institutional review boards. We recorded cost reimbursement payments to us from BMS as a reduction to research and development expense. Each party was otherwise responsible for its own internal costs, including internal personnel costs, incurred in connection with each Combination Therapy Trial.

Upon the effective date in April 2018, BMS paid us a non-refundable upfront cash payment of $1.0 billion. We are eligible to receive additional cash payments up to a total of approximately $1.4 billion upon the achievement of certain development and regulatory milestones and up to a total of $350.0 million upon the achievement of certain sales milestones. In April 2018, BMS also purchased 8,284,600 shares of our common stock for total additional cash consideration of $850.0 million.

We determined that the BMS Collaboration Agreement falls within the scope of ASC 808. As mentioned above, BMS shares certain percentages of development costs incurred by us and we share certain percentages of development costs incurred by BMS. We consider these activities to represent collaborative activities under ASC 808 and we recognize such cost sharing proportionately with the performance of the underlying services. We recognize BMS’ reimbursement of our expenses as a reduction of research and development expense and our reimbursement of BMS’ expenses as research and development expense. For the year ended December 31, 2018 and 2017, we recorded $62.5 million and $7.8 million, respectively, as a reduction of research and development expenses for BMS’ share of our expenses, net of our share of BMS’ expenses. As of December 31, 2018, we have recorded a receivable of $19.0 million from BMS in accounts receivable in our Consolidated Balance Sheet.

We analogized to ASC 606 for the accounting for our two performance obligations, consisting of the delivery of the licenses to develop and commercialize NKTR-214 and our participation on joint steering and other collaboration committees. We determined that our committee participation is not material.

We aggregated the total consideration of $1.85 billion received under the agreements and allocated it between the stock purchase and the revenue generating elements, because we and BMS negotiated the agreements together and the effective date of the BMS Collaboration Agreement was dependent upon the effective date of the Share Purchase Agreement. We recorded the estimated fair value of the shares of $790.2 million in stockholders’ equity based on the closing date price of our common stock of $99.36 per share, adjusted for a discount for lack of marketability reflecting the unregistered nature of the shares. We allocated the remaining $1,059.8 million to the transaction price of the collaboration agreement. We consider the future potential development, regulatory and sales milestones of up to approximately $1.8 billion to be variable consideration. We excluded these milestones from the transaction price as of December 31, 2018 because we determined such payments to be fully constrained under ASC 606 as the achievement of such milestone payments are uncertain and highly susceptible to factors outside of our control. We will re-evaluate the transaction price at each reporting period and as uncertain events are resolved or other changes in circumstances occur.

Accordingly, we allocated the entire transaction price of $1,059.8 million to the granting of the licenses and therefore recognized $1,059.8 million for the year ended December 31, 2018 as license, collaboration and other revenue.

We are a party to an exclusive research, development, license and manufacturing and supply agreement with Baxalta Incorporated (Baxalta), a subsidiary of Takeda Pharmaceutical Company Ltd. (Takeda), entered into in September 2005 to develop products designed to improve therapies for Hemophilia A patients using our PEGylation technology. Under the terms of the agreement, we are entitled to research and development funding for our active programs, which are now complete for Factor VIII, and are responsible for supplying Takeda with its requirements of our proprietary materials. Takeda is responsible for all clinical development, regulatory, and commercialization expenses. The agreement is terminable by the parties under customary conditions.

This Hemophilia A program includes ADYNOVATE^®, which was approved by the Food and Drug Administration (FDA) in November 2015 for use in adults and adolescents, aged 12 years and older, who have Hemophilia A, and is now marketed in the U.S., the European Union, and many other countries. As a result of the marketing authorization in the EU in January 2018, we earned a $10.0 million development milestone, which was received in March 2018. In the three months ended December 31, 2018, we recognized an additional $10.0 million milestone for annual sales of ADYNOVATE^®/ADYNOVI^TM reaching a certain specified amount. We are entitled to an additional sales milestone upon achievement of an annual sales target and royalties based on annual worldwide net sales of products resulting from this agreement.

In October 2017, we entered into a right to sublicense agreement with Baxalta, under which we granted to Baxalta the right to grant a nonexclusive sublicense to certain patents that were previously exclusively licensed to Baxalta under our 2005 agreement. Under the right to sublicense agreement, Baxalta paid us $12.0 million in November 2017 and agreed to pay us single digit royalty payments based upon net sales of the products covered under the sublicense throughout the term of the agreement.

Under our adoption of ASC 606 as of January 1, 2018, we determined that our satisfied performance obligations consist of granting the license, granting the right to sublicense and performing research and development services. We determined that we have an unsatisfied performance obligation related to our ongoing supply of PEGylation materials at a price less than their standalone selling prices. We updated the arrangement transaction price for the $10.0 million EU approval milestone upon achievement in January 2018 since we had previously excluded it due to the significant uncertainty from regulatory approval. Based on the terms of this milestone, we allocated the entire milestone to the license grant and research and development services, and therefore recognized the entire $10.0 million in year ended December 31, 2018 as we had previously satisfied those performance obligations. As of December 31, 2018, we have accounts receivable of $15.4 million and deferred revenue of $0.8 million related to this agreement.

Effective August 23, 2017, we entered into a worldwide license agreement with Eli Lilly and Company (Lilly) to co-develop NKTR-358, a novel immunological drug candidate that we invented. Under the terms of the agreement, we (i) received an initial payment of $150.0 million in September 2017 and are eligible for up to $250.0 million in additional development milestones, (ii) will co-develop NKTR-358 with Lilly with Nektar responsible for completing Phase 1 clinical development and certain drug product development and supply activities, (iii) will share with Lilly Phase 2 development costs with 75% of those costs borne by Lilly and 25% of the costs borne by Nektar, (iv) will have the option to contribute funding to Phase 3 development on an indication-by-indication basis ranging from zero to 25% of development costs, and (v) will have the opportunity to receive up to double-digit sales royalty rates that escalate based upon our Phase 3 development cost contribution and the level of annual global product sales. Lilly will be responsible for all costs of global commercialization, and we will have an option to co-promote in the U.S. under certain conditions. A portion of the development milestones may be reduced by 50% under certain conditions, related to the final formulation of the approved product and the timing of prior approval (if any) of competitive products with a similar mechanism of action, which could reduce these milestone payments by 75% if both conditions occur.

The agreement will continue until Lilly no longer has any royalty payment obligations to us or, if earlier, the termination of the agreement in accordance with its terms. The agreement may be terminated by Lilly for convenience, and may also be terminated under certain other circumstances, including material breach.

We identified our license grant to Lilly, our ongoing Phase 1 clinical development obligation, our drug product development obligation and our obligation to supply clinical trial materials as the significant performance obligations under the agreement and concluded that each of these deliverables represents a separate unit of accounting. The valuation of each performance obligation involves significant estimates and assumptions, including but not limited to, expected market opportunity and pricing, assumed royalty rates, clinical trial costs, timelines and likelihood of success; in each case these estimates and assumptions covering long time periods. We determined the selling price for the license based on a discounted cash flow analysis of projected revenues from NKTR-358 and development and commercial costs using a discount rate based on a market participant’s weighted average cost of capital adjusted for forecasting risk. We determined the selling prices for Phase 1 clinical development, and drug product development deliverables based on the nature of the services to be performed and estimates of the associated efforts and third-party rates for similar services.

Although we are entitled to significant development milestones under this arrangement, we did not include any of such milestones in the transaction price due to the significant uncertainties involved with clinical development. We have therefore determined the transaction price to consist of the upfront payment of $150.0 million in September 2017. Based on our estimates of the standalone selling prices of the performance obligations, we allocated the $150.0 million upfront payment as $125.9 million to the license, $17.6 million to the Phase 1 clinical development and $6.5 million to the drug product development.

Under our adoption of ASC 606 as of January 1, 2018, we made no changes to our deferred revenue balance. We concluded that it was appropriate to have recognized the $125.9 million of revenue allocated to the license upon the effective date of the license agreement in August 2017, since we determined that the license was a right to use our intellectual property, for which, as of the effective date, we had provided all necessary information to Lilly to benefit from the license and the license term had begun. We recognize revenue for the Phase 1 clinical development and drug product development using an input method, using costs incurred, as this method depicts our progress towards providing Lilly with the results of clinical trials and drug production processes. As of December 31, 2018, we have deferred revenue of approximately $8.3 million related to this agreement, which we expect to recognize through December 2019, the estimated end of our performance obligations under this agreement.

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

The term of the amended and restated agreement ends on October 29, 2020. In the event we become subject to a bankruptcy or insolvency proceeding, we cease to own or control the Facility, we fail to manufacture and supply or certain other events, Amgen or its designated third party will have the right to elect, among certain other options, to take title to the dedicated equipment and access the Facility to operate the Manufacturing Suite solely for the purpose of manufacturing the Polymer Materials. Amgen may terminate the amended and restated agreement for convenience or due to an uncured material default by us.

Under our adoption ASC 606 as of January 1, 2018, we determined that our obligation to manufacture and supply of our PEGylation materials and to maintain the dedicated manufacturing suite solely for the production of such materials for Amgen represented an obligation to stand ready to manufacture such materials. We concluded that we should recognize revenue based on the passage of time as this method depicts the satisfaction of Amgen’s right to require production of PEGylation materials at any time. As of December 31, 2018, we have deferred revenue of approximately $9.2 million related to this agreement, which we expect to recognize through October 2020, the estimated end of our obligations under this agreement.

On October 27, 2017, we terminated our license and supply agreement with Ophthotech Corporation (Ophthotech) dated September 2006, pursuant to 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 were the exclusive supplier of all of Ophthotech’s clinical and commercial requirements for our proprietary PEGylation reagent used in Fovista^®. The termination of our agreement with Ophthotech followed Opthotech’s previous announcements, in December 2016 and August 2017, that their three pivotal Phase 3 studies investigating the superiority of Fovista^® therapy in combination with Lucentis^® therapy compared to Lucentis^® monotherapy and evaluating Fovista^® in combination with Eylea^® or Avastin^® compared to Eylea^® or Avastin^® monotherapy for the treatment of wet age-related macular degeneration (AMD) did not achieve the pre-specified primary endpoints.

Under our agreement with Ophthotech, in June 2014, we received a $19.8 million payment from Ophthotech in connection with its licensing agreement with Novartis. In addition, in January 2017, we received a $12.7 million advance payment from Ophthotech, which included $10.4 million for reagent shipments recognized in the second quarter of 2017 as well as approximately $2.3 million for 2017 minimum purchase requirements. As a result of the termination of this agreement, we recognized the remaining $18.0 million of deferred revenue from this arrangement in the three months ended December 31, 2017.

In December 2017, Bayer Healthcare LLC (Bayer) terminated our co-development, license and co-promotion agreement entered into in August 2007 to develop a specially-formulated inhaled Amikacin. Under this agreement, we were responsible for development, manufacturing and supply of our proprietary nebulizer device included in the Amikacin product. Bayer was responsible for most clinical development and commercialization activities and costs, all activities and costs to support worldwide regulatory filings, approvals and related activities, further development of Amikacin Inhale and final product packaging and distribution. The termination of this agreement followed Bayer’s announcement in November 2017 that the Phase 3 Amikacin Inhale clinical program for the treatment of intubated and mechanically ventilated patients with Gram-negative pneumonia did not meet its primary endpoint or key secondary endpoints.

Under this collaboration, we received an upfront payment of $40.0 million (which was paid to us in 2007) and milestone payments totaling $30.0 million (the last of which was paid to us in 2013). As a result of the termination of the agreement, we recognized the remaining $16.8 million of deferred revenue related to this arrangement in the three months ended December 31, 2017.

AstraZeneca AB: MOVANTIK^® (naloxegol oxalate), previously referred to as naloxegol and NKTR-118,

In September 2009, we entered into an agreement with AstraZeneca AB (AstraZeneca) under which we granted AstraZeneca a worldwide, exclusive license under our patents and other intellectual property to develop, market, and sell MOVANTIK^®. AstraZeneca is responsible for all research, development and commercialization and is responsible for all drug development and commercialization decisions for MOVANTIK^®. In September 2014 and December 2014, MOVANTIK^® /MOVENTIG^® was approved in the US and EU, respectively. As of December 31, 2018, we have received a total of $385.0 million of upfront and contingent milestone payments from this agreement, all of which was received in or before 2015. We are entitled to significant and escalating double-digit royalty payments and sales milestone payments based on annual worldwide net sales of MOVANTIK^® / MOVENTIG^®.

In March 2016, AstraZeneca announced that it had entered into an agreement with ProStrakan Group plc, a subsidiary of Kyowa Hakko Kirin Co. Ltd. (Kirin), granting Kirin exclusive marketing rights to MOVENTIG^® in the EU, Iceland, Liechtenstein, Norway and Switzerland. Under our license agreement with AstraZeneca, we and AstraZeneca will share the upfront payment, market access milestone payments, royalties and sales milestone payments made by Kirin to AstraZeneca with AstraZeneca receiving 60% and Nektar receiving 40%. In the years ended December 31, 2017 and 2016, we recognized a total of $4.6 million and $33.0 million, respectively, related to our share of license-related payments made from Kirin to AstraZeneca. As of December 31, 2018, we do not have deferred revenue related to our agreement with AstraZeneca.

In addition, as of December 31, 2018, we have a number of other collaboration agreements, including with our collaboration partners UCB and Halozyme Therapeutics, Inc., under which we are entitled to up to a total of $45.5 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. As of December 31, 2018, we have deferred revenue of approximately $6.4 million related to these other collaboration agreements.