On December 20, 2018, we entered into a series of agreements with Gilead focused on the development and commercialization of up to five novel immuno-oncology therapies. Pursuant to the terms of the license agreement, the option and license agreements and the stock purchase agreement we entered into with Gilead (each defined below and, collectively, the “Gilead Collaboration Agreements”), at the closing of the transaction on January 23, 2019 (the “Effective Date”), we received an upfront cash payment from Gilead of $120.0 million and Gilead made a $30.0 million equity investment in Agenus. We are also eligible to receive up to $1.7 billion in aggregate potential milestones.

Pursuant to the terms of a license agreement between the parties (the “License Agreement”), we granted Gilead an exclusive, worldwide license under certain of our intellectual property rights to develop, manufacture and commercialize our preclinical bispecific antibody, AGEN1423 (now GS-1423), in all fields of use. Pursuant to the License Agreement, Gilead is responsible for all of the development, manufacturing and commercialization costs for any products that Gilead may develop under the License Agreement. In addition, Gilead also received the right of first negotiation for two of our undisclosed antibody programs. The License Agreement will continue until all of Gilead’s applicable payment obligations under the License Agreement have been performed or have expired, or the agreement is earlier terminated. Under the terms of the License Agreement, each party has the right to terminate the agreement for material breach by, or insolvency of, the other party. Gilead may also terminate the License Agreement in its entirety, or on a product-by-product or country-by-country basis, for convenience upon ninety (90) days’ notice. Pursuant to the terms of the License Agreement, we are eligible to receive potential development and commercial milestones of up to $552.5 million in the aggregate, as well as tiered royalty payments on aggregate net sales ranging from the high single digit to mid-teen percent, subject to certain reductions under certain circumstances as described in the License Agreement. We filed an investigational new drug (“IND”) application for AGEN1423 (now GS-1423) in February 2019, and the IND was accepted by the FDA in March 2019.

Pursuant to the terms of two separate option and license agreements between the parties (each, an “Option and License Agreement” and together, the “Option and License Agreements”), we granted Gilead exclusive options to license exclusively (“License Option”) our bispecific antibody, AGEN1223, and our monospecific antibody, AGEN2373 (together, the “Option Programs”), during the respective Option Periods (defined below). Pursuant to the terms of the Option and License Agreements, we agreed to grant Gilead an exclusive, worldwide license under our intellectual property rights to develop, manufacture and commercialize AGEN1223 or AGEN2373, as applicable, in all fields of use upon Gilead’s exercise of the applicable License Option. Gilead is entitled to exercise its License Option for either or both Option Programs at any time up until ninety (90) days following Gilead’s receipt of a data package with respect to the first complete Phase 1b clinical trial for each Option Program (the “Option Period”). During the Option Period, we are responsible for the costs and expenses related to the development of the Option Programs. After Gilead’s exercise of a License Option, if at all, Gilead would be responsible for all development, manufacturing and commercialization activities relating to the relevant Option Program at Gilead’s cost and expense.

During the Option Period, we are eligible to receive milestones of up to $30.0 million in the aggregate. If Gilead exercises a License Option, it would be required to pay an upfront license exercise fee of $50.0 million for each License Option that is exercised. Following any exercise of a License Option, we would be eligible to receive additional development and commercial milestones of up to $520.0 million in the aggregate for each such Option Program, as well as tiered royalty payments on aggregate net sales. For either, but not both, of the Option Programs, we will have the right to opt-in to share Gilead’s development and commercialization costs in the United States for such Option Program in exchange for a profit (loss) share on a 50:50 basis and revised milestone payments. If we opt-in under one Option and License Agreement, our right to opt-in under the other Option and License Agreement automatically terminates. We filed INDs for each of AGEN1223 and AGEN2373 in 2019, and both assets are now in clinical development.

Unless earlier terminated, each Option and License Agreement will continue until the earlier of (i) the expiration of the Option Period, without Gilead’s exercise of the License Option; and (ii) the date all of Gilead’s applicable payment obligations under the Option and License Agreement have been performed or have expired. Under the terms of each Option and License Agreement, we and Gilead each have the right to terminate the agreement for material breach by, or insolvency of, the other party. Gilead may also terminate an Option License Agreement in its entirety, or on a product-by-product or country-by-country basis for convenience upon ninety (90) days’ notice.

Pursuant to the terms of a stock purchase agreement between the parties (the “Stock Purchase Agreement”), Gilead purchased 11,111,111 shares of Agenus common stock (the “Shares”) for an aggregate purchase price of $30.0 million, or $2.70 per share. Gilead owned approximately 8.5% of the outstanding shares of Agenus common stock after such purchase. Under the Stock Purchase Agreement, Gilead has agreed (i) not to dispose of any of the Shares for a period of 12 months, (ii) to certain standstill provisions that generally preclude it from acquiring more than 15% of Agenus’ outstanding voting stock after taking into account the purchase of the Shares and (iii) to vote the Shares in accordance with the recommendations of the Agenus board of directors in connection with certain equity incentive plan or compensation matters for a period of 12 months. In the Stock Purchase Agreement we agreed to register the Shares for resale under the Securities Act of 1933, and in October 2019 we filed a registration statement with the SEC accordingly.

We identified the following performance obligations under the Gilead Collaboration Agreements: (1) the license that we granted to Gilead pursuant to the License Agreement (the “AGEN1423 License”), (2) our obligation to complete manufacturing and know-how tech transfer activities to Gilead pursuant to the License Agreement to enable Gilead or its third party contract manufacturing organization to manufacture the licensed antibody (the “AGEN1423 Technology Transfer”), (3) our obligation to advance development of AGEN1223 to the option exercise point pursuant to the AGEN1223 Option and License Agreement (such development activities, the “AGEN1223 R&D Services”), and (4) our obligation to advance development of AGEN2373 to the option exercise point pursuant to the AGEN2373 Option and License Agreement (such development activities, the “AGEN2373 R&D Services”).

We determined that the AGEN1423 License was both capable of being distinct and distinct within the context of the contract given both the advanced stage of development and that the IND was anticipated to be accepted within a short period of time after the Effective Date. Gilead can begin deriving benefit from the license prior to the AGEN1423 Technology Transfer being completed. The technology transfer plan includes an extensive list of items to be transferred over time and is separate from the transfer of the AGEN1423 License which occurred at contract inception. As a result, we concluded that the AGEN1423 License and AGEN1423 Technology Transfer are separate performance obligations.

We considered whether the AGEN1223 R&D Services and AGEN2373 R&D Services were distinct from one another and from the performance obligations related to AGEN1423. We determined that the research and development services related to each antibody were both capable of being distinct and distinct within the context of the contract given that each program is governed by a separate option agreement with a separate development plan. The services performed to develop each program are independent of one another, and the antibodies are in different stages of development. We concluded that the AGEN1223 R&D Services and AGEN2373 R&D Services are separate performance obligations.

We determined that there were no significant financing components, noncash consideration, or amounts that may be refunded to the customer, and as such the total upfront fixed consideration of license and research and development fees totaling $120.0 million would be included in the total transaction price. In addition to the fixed consideration, the variable consideration milestones related to IND acceptance for each of the three antibodies was also included in the transaction price. We determined that based on the likelihood of the triggering event occurring for the acceptance of each IND filling, the most likely amount for each of the three milestones was the stated value, totaling $22.5 million. The variable consideration related to each performance obligation will be allocated entirely to that specific performance obligation. The remaining fixed consideration will be allocated using the relative standalone selling price method.

We determined the estimated standalone selling price of the AGEN1423 License by applying a risk adjusted, net present value, estimate of future cash flow approach. We determined the estimated standalone selling price of the AGEN1423 Technology Transfer, and AGEN1223 R&D Services and AGEN2373 R&D Services by using the estimated costs of satisfying these performance obligations, plus an appropriate margin for such services.

Revenue attributable to the AGEN1423 License was recognized at a point-in-time, upon delivery of the license to Gilead at the Effective Date. The AGEN1423 Technology Transfer, AGEN1223 R&D Services and AGEN2373 R&D Services are satisfied over time and revenue attributable to these performance obligations will be recognized as the related services are being performed using the input of costs incurred over total costs expected to be incurred. We believe this is the best measure of progress because other measures do not reflect how we transfer our performance obligations to Gilead. A cost-based input method of revenue recognition requires management to make estimates of costs to complete our performance obligations. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

For the year ended December 31, 2019, we recognized $86.1 million of license and collaboration revenue related to the Gilead Collaboration Agreement. This amount included $20.6 million of the transaction price recognized based on the partial satisfaction of the over time performance obligations as of period end.

We expect to recognize deferred research and development revenue of $28.7 million and $27.7 million in 2020 and 2021, respectively, related to performance obligations that are unsatisfied or partially unsatisfied as of December 31, 2019.

In November 2019, we entered into a License Agreement with UroGen Pharma Ltd. (the “UroGen License Agreement”) in which we granted a license of AGEN1884 for use with UroGen's sustained release technology for intravesical delivery in patients with urinary tract cancers. Pursuant to the terms of the UroGen License Agreement, we received an upfront cash payment from UroGen of $10.0 million. We are eligible to receive up to $200.0 million in potential development, regulatory and commercial milestones, as well as 14-20% royalties on net sales of the products containing AGEN1884.

We identified the following performance obligations under the UroGen License Agreement: (1) the license of AGEN1884 that we granted UroGen, and (2) the clinical supply of AGEN1884 that we agreed to supply to UroGen. We determined that the license of AGEN1884 was both capable of being distinct and distinct within the context of the contract as the license has significant stand-alone functionality as of contract inception based on the advanced development stage of AGEN1884. We also determined that the clinical supply of AGEN1884 was both capable of being distinct and distinct within the context of the contract as it was considered a readily available resource in the market.

We determined that there were no significant financing components, noncash consideration, or amounts that may be refunded to the customer, and as such the total upfront fixed consideration of the license totaling $10.0 million would be included in the total transaction price. We concluded that the combined standalone selling price of the license approximated the $10.0 million upfront fee and as such the full amount will be recognized at a point-in-time, upon delivery of the license to UroGen at contract inception. We will not estimate the transaction price in order to recognize the revenue related to the AGEN1884 supply due to the “as invoiced” practical expedient.

For the year ended December 31, 2019, we recognized $10.0 million of license and collaboration revenue related to the UroGen License Agreement.

In July 2006, we entered into a license agreement and a supply agreement with GSK for the use of QS-21 Stimulon (the “GSK License Agreement” and the “GSK Supply Agreement”, respectively). In January 2009, we entered into an Amended and Restated Manufacturing Technology Transfer and Supply Agreement (the “Amended GSK Supply Agreement”) under which GSK has the right to manufacture all of its requirements of commercial grade QS-21 Stimulon. GSK is obligated to supply us (or our affiliates, licensees, or customers) certain quantities of commercial grade QS-21 Stimulon for a stated period of time. Under these agreements, GSK paid an upfront license fee of $3.0 million and agreed to pay aggregate milestones of $5.0 million. In July 2007, the Amended GSK Supply Agreement was further amended, and we were paid an additional fixed fee of $7.3 million. In March 2012 we entered into a First Right to Negotiate and Amendment Agreement amending the GSK License Agreement and the Amended GSK Supply Agreement to clarify and include additional rights for the use of our QS-21 Stimulon (the “GSK First Right to Negotiate Agreement”). In addition, we granted GSK the first right to negotiate for the purchase of the Company or certain of our assets, which such rights expired in March 2017. As consideration for entering into the GSK First Right to Negotiate Agreement, GSK paid us an upfront, non-refundable payment of $9.0 million, $2.5 million of which is creditable toward future royalty payments. As of December 31, 2017, we had received all of the potential $24.3 million in upfront and milestone payments related to the GSK Agreements. We were also generally entitled to receive 2% royalties on net sales of prophylactic vaccines for a period of 10 years after the first commercial sale of a resulting GSK product, but we sold these royalty rights to HCR in January 2018 pursuant to the HCR Royalty Purchase Agreement (See Note 17). The GSK License and Amended GSK Supply Agreements may be terminated by either party upon a material breach if the breach is not cured within the time specified in the respective agreement. The termination or expiration of the GSK License Agreement does not relieve either party from any obligation which accrued prior to the termination or expiration. Among other provisions, the license rights granted to GSK survive expiration of the GSK License Agreement. The license rights and payment obligations of GSK under the Amended GSK Supply Agreement survive termination or expiration, except that GSK's license rights and future royalty obligations do not survive if we terminate due to GSK's material breach unless we elect otherwise.

We assessed this arrangement in accordance with ASC 606 and concluded that the contract counterparty, GSK, is a customer. We identified the following performance obligations under the contract: (1) an exclusive license to QS-21 in the specified field and related technology transfer; and (2) and exclusive license to QS-21 in an additional field.

We determined that the fixed payments of $19.3 million constituted all of the consideration to be included in the transaction price and to be allocated to the performance obligations based on their relative stand-alone selling prices. The fixed upfront consideration is recognized under ASC 606 based on when control of the combined performance obligation is transferred to the customer, which corresponds with the service period (through December 2014). At contract inception, the milestones of $5.0 million had been excluded from the transaction price, as we could not conclude that it was probable a significant reversal would not occur. Event driven milestones are a form of variable consideration as the payments are variable based on the occurrence of future events. As part of its estimation of the amount, we considered numerous factors, including that receipt of the milestones is outside of our control and contingent upon success in future clinical trials and the licensee’s efforts. Recognition of event driven milestones should be recognized when the variable consideration is able to be estimated. As of December 31, 2017, all milestones had been received, and therefore recognized.

Any consideration related to royalties will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to GSK and therefore have also been excluded from the transaction price.

For the year ended December 31, 2019, we recognized $15.1 million in royalty sales milestone revenue and $30.4 million in non-cash royalty revenue. For the year ended December 31, 2018, we recognized $17.3 million in non-cash royalty revenue. For the year ended December 31, 2017, we recognized $1.0 million in research and development revenue related to the achievement of a milestone.

The cumulative impact of changing the timing of revenue recognition for the GSK License and Amended GSK Supply Agreements as of January 1, 2018 was a decrease to stockholders' deficit of approximately $2.5 million and a corresponding decrease in deferred revenue of $2.5 million for the portion of the upfront fee creditable toward future royalties, as described above. This amount was included in the transition adjustment, as under ASC 606 it would have been recognized as revenue in March 2012, at the time of the amendment.

During the quarter ended June 30, 2014, we entered into a collaboration and license agreement with Merck to discover and optimize fully-human antibodies against two undisclosed cancer targets using the Retrocyte Display^®. Under this agreement, Merck is responsible for the clinical development and commercialization of antibodies generated under the collaboration. There are no unsatisfied performance obligations relating to this contract. Pursuant to the XOMA Royalty Purchase Agreement (see Note 17), we sold to XOMA 33% of the future royalties and 10% of the future milestones that we are entitled to receive from Merck, and we remain eligible to receive from Merck approximately $85.5 million in potential payments associated with the completion of certain clinical, regulatory and commercial milestones, as well as 67% of all future royalties on worldwide product sales.

For the year ended December 31, 2019, no revenue was recognized. For each of the years ended December 31, 2018 and 2017, we recognized $4.0 million in research and development revenue related to the achievement of milestones.

The adoption of ASC 606 did not have an impact on the Merck collaboration and license agreement.

On January 9, 2015 and effective February 19, 2015, we entered into a global license, development and commercialization agreement (the “Collaboration Agreement”) with Incyte pursuant to which the parties plan to develop and commercialize novel immuno-therapeutics using our antibody discovery platforms. The Collaboration Agreement was initially focused on four checkpoint modulator programs directed at GITR, OX40, LAG-3 and TIM-3. In addition to the four identified antibody programs, the parties have an option to jointly nominate and pursue the development and commercialization of antibodies against additional targets during a five-year discovery period which, upon mutual agreement of the parties for no additional consideration, can be extended for an additional three years. In November 2015, we and Incyte jointly nominated and agreed to pursue the development and commercialization of three additional CPM targets. In February 2017, we amended the Collaboration Agreement by entering into a First Amendment to License, Development and Commercialization Agreement (the “First Amendment”). See “Amendment” section below.In October 2019, we further amended the Collaboration Agreement by entering into a Second Amendment to License, Development and Commercialization Agreement (the “Second Amendment”). See “Amendments” section below.

Pursuant to the XOMA Royalty Purchase Agreement, we sold to XOMA 33% of the future royalties and 10% of the future milestones that we were entitled to receive from Incyte, excluding the $5.0 million milestone that we recognized in the three months ended September 30, 2018. As of December 31, 2018, we remain eligible to receive up to $450.0 million in future potential development, regulatory and commercial milestones across all programs in the collaboration, as well as 67% of all future royalties on worldwide product sales.

On January 9, 2015, we also entered into the Stock Purchase Agreement with Incyte Corporation whereby, for an aggregate purchase price of $35.0 million, Incyte purchased approximately 7.76 million shares of our common stock.

Under the terms of the Collaboration Agreement, we received non-creditable, nonrefundable upfront payments totaling $25.0 million. In addition, until the Amendment, the parties shared all costs and profits for the GITR, OX40 and two of the additional antibody programs on a 50:50 basis (profit-share products), and we were eligible to receive up to $20.0 million in future contingent development milestones under these programs. Incyte is obligated to reimburse us for all development costs that we incur in connection with the TIM-3, LAG-3 and one of the additional antibody programs (royalty-bearing products) and we are eligible to receive (i) up to $155.0 million in future contingent development, regulatory, and commercialization milestone payments and (ii) tiered royalties on global net sales at rates generally ranging from 6% to 12%. For each royalty-bearing product, we will also have the right to elect to co-fund 30% of development costs incurred following initiation of pivotal clinical trials in return for an increase in royalty rates. Additionally, we had the option to retain co-promotion participation rights in the United States on any profit-share product. Through the direction of a joint steering committee, until the Amendment, the parties anticipated that, for each program, we would serve as the lead for pre-clinical development activities through investigational new drug (“IND”) application filing, and Incyte would serve as the lead for clinical development activities. The parties initiated the first clinical trials of antibodies arising from these programs in 2016. For each additional program beyond GITR, OX40, TIM-3 and LAG-3 that the parties elect to bring into the collaboration, we will have the option to designate it as a profit-share product or a royalty-bearing product.

The Collaboration Agreement will continue as long as (i) any product is being developed or commercialized or (ii) the discovery period remains in effect. Incyte may terminate the Collaboration Agreement or any individual program for convenience upon 12 months’ notice. The Collaboration Agreement may also be terminated by either party upon the occurrence of an uncured material breach of the other party or by us if Incyte challenges patent rights controlled by us. In addition, either party may terminate the Collaboration Agreement as to any program if the other party is acquired and the acquiring party controls a competing program.

Pursuant to the terms of the First Amendment, the GITR and OX40 programs immediately converted from profit-share programs to royalty-bearing programs and we became eligible to receive a flat 15% royalty on global net sales should any candidates from either of these two programs be approved. Incyte is now responsible for global development and commercialization and all associated costs for these programs. In addition, the profit-share programs relating to TIGIT and one undisclosed target were removed from the collaboration, with the undisclosed target reverting to Incyte and TIGIT to Agenus. Should any of those programs be successfully developed by a party, the other party will be eligible to receive the same milestone payments as the royalty-bearing programs and royalties at a 15% rate on global net sales. The terms for the remaining three royalty-bearing programs targeting TIM-3, LAG-3 and one undisclosed target remain unchanged, with Incyte being responsible for global development and commercialization and all associated costs. The Amendment gives Incyte exclusive rights and all decision-making authority for manufacturing, development, and commercialization with respect to all royalty-bearing programs.

In connection with the First Amendment, Incyte paid us $20.0 million in accelerated milestones related to the clinical development of the antibody candidates targeting GITR and OX40.

In February 2017, we also entered into an Additional Stock Purchase Agreement with Incyte, pursuant to which Incyte purchased 10 million shares of our common stock at a purchase price of $6.00 per share.

Pursuant to the terms of the Second Amendment, we transitioned preclinical development and IND preparation of the undisclosed target to Incyte.

We identified the following performance obligations under the Incyte Collaboration Agreement, as amended: (1) combined license and related research and development (“R&D”) services to a GITR antibody, (2) combined license and related R&D services to an OX40 antibody, (3) combined license and related R&D services to a TIM-3 antibody, (4) combined license and related R&D services to a LAG-3 antibody, (5) combined license and related R&D services to a TIGIT antibody, (6) combined license and related R&D services to a first undisclosed target, (7) combined license and related R&D services to a second undisclosed target, and (8) the option to license certain other mutually agreed-upon antibodies combined with related R&D Services (“Assumed Project Options Development”). Each of these performance obligations consists of a license or option to a license and related R&D services through the filing of an IND for each antibody candidate.

We concluded that the licenses could be used with other readily available resources if the know-how was also transferred with the license; however, our knowledge and experience is necessary for further development of the licensed antibodies. Therefore, we determined that each of the licensed antibodies and the related developmental R&D services should be treated as a combined performance obligation. We also evaluated whether the Assumed Project Options Development was a material right. At contract inception Incyte paid us a nonrefundable access fee for the ability to exercise the option and bring additional targets into the program. Both we and Incyte have the ability to explore targets and, if mutually agreed upon, convert those targets into assumed projects for no additional license fee. We concluded that Assumed Project Options Development represents a material right and is therefore a performance obligation.

We determined that there were no significant financing components, noncash consideration, or amounts that may be refunded to the customer, and as such the total upfront fixed consideration of the $10.0 million license fee and $15.0 million project access fee would be included in the total transaction price of $25.0 million. This amount was then allocated to the performance obligations on a relative stand-alone selling price basis.

The estimated variable consideration to be recognized for developmental R&D services and related reimbursable expenses (“Development Costs”) was determined based on the forecasted amounts in the research plan that had been approved by the both parties via the joint steering committee (“JSC”). Under the Agreement, Development Costs related to Profit-Sharing products are split equally between us and Incyte. Therefore, our expected revenue is 50% of the costs of these programs. Based on review of the budgets presented at the JSC meetings, as well as costs of previous R&D projects, we expected the total development costs over the term of the contract would be $43.4 million. This amount was allocated entirely to the distinct R&D services that forms part of each performance obligation.

We determined that the transaction price of the Collaboration Agreement was $75.2 million as of December 31, 2019, a decrease of $3.4 million from the transaction price of $78.6 million as of December 31, 2018. In order to determine the transaction price, we evaluated all the payments to be received during the duration of the contract. We determined that the fixed upfront license fee and project access fee of $10.0 million and $15.0 million, respectively, and the $50.2 million of actual and estimated variable consideration for development costs (including R&D services) and milestones constituted consideration to be included in the transaction price, which is allocated among the performance obligations.

For payments made to Incyte related to their work performed on profit-sharing programs, we considered that we will receive a benefit through the performance of a series of distinct R&D services by Incyte. Additionally, the R&D services are being provided by Incyte at fair value. Therefore, the amount paid to Incyte represents the fair value of the services performed, and no excess will be allocated as a reduction of the transaction price. We will record any consideration paid to Incyte in the same manner that we would purchases for other vendors, classified as R&D expense.

In summary, each of the performance obligations includes a license or option to a license, and respective R&D services that will be performed over time from program initiation through the filing of an IND with respect to each antibody candidate. We have determined that the combined performance obligation is satisfied over time, and that the input method should be applied for all performance obligations that have consideration allocated to them. The cost-cost measure will be applied based on the percentage of completion of R&D services provided during the period compared to the respective budget. We believe this is the best measure of progress because other measures do not reflect how we transfer our performance obligation to Incyte. We will recognize the fixed consideration allocated to each performance obligation over time as the related R&D services are being performed using the input of R&D costs incurred over total R&D costs expected to be incurred through IND filing, beginning on the date a license is granted. A cost-based input method of revenue recognition requires management to make estimates of costs to complete our performance obligations. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

We considered the nature of the arrangement between Incyte and us in evaluating the classification of the payments to be received under the cost-sharing arrangement. We do not currently have any commercial products available for sale. Our primary operations to date have included research and development activities, licensing intellectual property and performing R&D services for external parties. Accordingly, arrangements such as this represent our ongoing business operations. Therefore, we have concluded that payments received from Incyte under the cost-sharing arrangement represent payments made to us as part of our on-going operations and should be classified as revenue as such amounts are earned.

For the year ended December 31, 2019, we recognized approximately $3.7 million of license and collaboration revenue. This amount included $2.0 million of the transaction price for the Incyte Collaboration Agreement recognized based on proportional performance and $1.7 million for research and development services. For the year ended December 31, 2018, we recognized approximately $15.5 million of license and collaboration revenue. This amount included $1.3 million of the transaction price for the Incyte Collaboration Agreement recognized based on proportional performance, $10.0 million for the achievement of milestones and $4.2 million for research and development services. For year ended December 31, 2017, we recognized approximately $37.3 million of research and development revenue.

The cumulative impact of the adoption of ASC 606 for the Incyte Collaboration Agreement as of January 1, 2018 was a decrease to stockholders' deficit of approximately $6.4 million and a corresponding decrease in deferred revenue of $6.4 million.

The following table presents revenue (in thousands) for years ended December 31, 2019, 2018 and 2017, disaggregated by geographic region and revenue type. Revenue by geographic region is allocated based on the domicile of our respective business operations.

	Year ended December 31, 2019
	United States		Europe		Total
Revenue Type
Research and development services	$	1,707	$	—	$	1,707
License fees		75,500		—		75,500
Royalty sales milestone		15,100		—		15,100
Manufacturing services		3,337		—		3,337
Recognition of deferred research and development revenue		22,638		—		22,638
Recognition of deferred grant revenue		652		690		1,342
Non-cash royalties and milestones		30,424		—		30,424
	$	149,358	$	690	$	150,048

	Year ended December 31, 2018
Revenue Type
Research and development services	$	4,150	$	—	$	4,150
License and collaboration milestones		10,000		4,000		14,000
Recognition of deferred research and development revenue		1,325		—		1,325
Non-cash royalty revenue		17,309		—		17,309
	$	32,784	$	4,000	$	36,784

	Year ended December 31, 2017
Revenue Type
Research and development services	$	14,615	$	—	$	14,615
License and collaboration milestones		21,000		3,994		24,994
Recognition of deferred research and development revenue		3,100		—		3,100
Grant revenue		168		—		168
	$	38,883	$	3,994	$	42,877

Contract assets primarily relate to our rights to consideration for work completed in relation to our R&D services performed but not billed at the reporting date. The contract assets are transferred to the receivables when the rights become unconditional. Currently, we do not have any contract assets which have not transferred to a receivable. We had no asset impairment charges related to contract assets in the period. The contract liabilities primarily relate to contracts where we received payments but have not yet satisfied the related performance obligations. The advance consideration received from customers for R&D services or licenses bundled with other promises is a contract liability until the underlying performance obligations are transferred to the customer.

The following table provides information about contract assets and contract liabilities from contracts with customers (in thousands):

Year ended December 31, 2019	Balance at beginning of period		Additions		Deductions			Balance at end of period
Contract assets:
Unbilled receivables from collaboration partners	$	-	$	-	$	-		$	-
Contract liabilities:
Deferred revenue	$	2,052	$	77,000	$	(22,638	)	$	56,414

The change in contract liabilities is primarily related to the addition of $77.0 million of deferred revenue from the Gilead Collaboration Agreement, offset by the recognition of $20.6 million of revenue related to this same agreement and $2.0 million of revenue related to the Incyte Collaboration Agreement during the year ended December 31, 2019. Deferred revenue related to the Gilead Collaboration Agreement of $56.4 million as of December 31, 2019, which was comprised of the $142.5 million initial transaction price, less $86.1 million of license and collaboration revenue recognized from the effective date of the contract, will be recognized as the combined performance obligation is satisfied.

We also recorded a $1.2 million receivable as of December 31, 2019 for research and development and manufacturing services provided.

In the year ended December 31, 2019, we did not recognize any revenue from amounts included in the contract asset or the contract liability balances from performance obligations satisfied in previous periods. None of the costs to obtain or fulfill a contract were capitalized.