On December 21, 2017, the Company entered into the Reneo License Agreement, under which Reneo obtained an exclusive, worldwide, sublicensable license to develop and commercialize the Company’s peroxisome proliferation activated receptor delta (PPAR-δ) agonist program, including the compound HPP593, for therapeutic, prophylactic or diagnostic application in humans. Under the terms of the Reneo License Agreement, Reneo paid the Company an upfront cash payment of $3.0 million. The Company is eligible to receive additional potential development, regulatory and sales-based milestone payments totaling up to $94.5 million. In addition, Reneo is obligated to pay the Company royalty payments at mid-single to low-double digit rates, based on tiers of annual net sales of licensed products. Such royalties will be payable on a licensed product-by-licensed product and country-by-country basis until the latest of expiration of the licensed patents covering a licensed product in a country, expiration of data exclusivity rights for a licensed product in a country or a specified number of years after the first commercial sale of a licensed product in a country. As additional consideration, the Company has also received common stock and certain participation rights representing a minority equity interest in Reneo.

Pursuant to the terms of the Reneo License Agreement, the Company is required to provide technology transfer services for a defined period after the effective date. In accordance with ASC Topic 606, the Company identified all of the performance obligations at the inception of the Reneo License Agreement. The significant obligations were determined to be the license and the technology transfer services. The Company has determined that the license and technology transfer services represent a single performance obligation because they were not capable of being distinct on their own. The transaction price has been fully allocated to this combined performance obligation.

The Company determined that there was no discernable pattern in which the technology services would be provided during the transfer services period. As such, the Company determined that the straight-line method would be used to recognize revenue over the transfer service period. The Company recognized $1.7 million of revenue related to this combined performance obligation for the year ended December 31, 2019. As of December 31, 2019, revenue allocated to this performance obligation had been fully recognized.

During the year ended December 31, 2021, $2.0 million of revenue was recognized due to the satisfaction of a development milestone under the license agreement. This amount was fully recognized as revenue during the year ended December 31, 2021, as the related performance obligation was fully satisfied. The remaining milestone payments that the Company is eligible to receive have not been included in the transaction price as of December 31, 2021, as it is not considered probable that such payments will be received.

On December 21, 2017, the Company entered into a License Agreement with Huadong (the “Huadong License Agreement”), under which Huadong obtained an exclusive and sublicensable license to develop and commercialize the Company’s glucagon-like peptide-1 receptor agonist (“GLP-1r”) program, including the compound TTP273, for therapeutic uses in humans or animals, in China and certain other Pacific Rim territories, including Australia and South Korea (collectively, the “Huadong License Territory”). Additionally, under the Huadong License Agreement, the Company obtained a non-exclusive, sublicensable, royalty-free license to develop and commercialize certain Huadong patent rights and know-how related to the Company’s GLP-1r program for therapeutic uses in humans or animals outside of the Huadong License Territory. Under the terms of the Huadong License Agreement, as amended, Huadong paid the Company an initial license fee of $8.0 million and is obligated to pay potential development and regulatory milestone payments totaling up to $22.0 million, with an additional potential regulatory milestone of $20.0 million if Huadong receives regulatory approval for a central nervous system indication. In addition, the Company is eligible for an additional $50.0 million in potential sales-based milestones, as well as royalty payments ranging from low-single to low-double digit rates, based on tiered sales of licensed products.

On January 14, 2021, the Company entered into the First Huadong Amendment which eliminated the Company’s obligation to sponsor a multi-region clinical trial (the “Phase 2 MRCT”), and corresponding obligation to contribute up to $3.0 million in support of such trial. The amendment also reduced the total potential development and regulatory milestone payments by $3.0 million.

Prior to the First Amendment, the Company had allocated a portion of the transaction price to the obligation to sponsor and conduct a portion of the Phase 2 MRCT. Upon the removal of this performance obligation, the Company evaluated the impact of the modification under the provisions of ASC Topic 606 and performed a reallocation of the transaction price among the remaining performance obligations. This resulted in the recognition of approximately $1.0 million of revenue on a cumulative catch up basis during the year ended December 31, 2021. The majority of the transaction price originally allocated to the Phase 2 MRCT performance obligation was reallocated to the license and technology transfer services combined performance obligation discussed below, which had already been completed. The reallocation of the purchase price in connection with the First Huadong Amendment was made based on the relative estimated selling prices of the remaining performance obligations.

The significant performance obligations under this license agreement, as amended, were determined to be (i) the exclusive license to develop and commercialize the Company’s GLP-1r program, (ii) technology transfer services related to the chemistry and manufacturing know-how for a defined period after the effective date, (iii) the Company’s obligation to participate on a joint development committee (the “JDC”), and (iv) other obligations considered to be de minimis in nature.

The Company has determined that the license and technology transfer services related to the chemistry and manufacturing know-how represent a combined performance obligation because they were not capable of being distinct on their own. The Company also determined that there was no discernable pattern in which the technology transfer services would be provided during the transfer service period. As such, the Company recognized the revenue related to this combined performance obligation using the straight-line method over the transfer service period. This combined performance obligation was considered complete as of December 31, 2018. In connection with the First Huadong Amendment, the Company recognized approximately $1.0 million of revenue related to this performance obligation during the year ended December 31, 2021 due to the reallocation of the transaction price among the performance obligations remaining after the First Huadong Amendment.

The Company also determined that the obligation to participate in the joint development committee (the “JDC”) to oversee the development of products should be treated as a separate performance obligation. A portion of the total consideration received under the Huadong License Agreement was allocated to this performance obligation based on its estimated standalone selling price. A portion of this amount remains deferred as of December 31, 2021, and revenue will be recognized using the proportional performance model over the period of the Company’s participation on the JDC. The unrecognized amount of the transaction price allocated to this performance obligation as of December 31, 2021, was $0.1 million. An immaterial amount of revenue was recognized for this performance obligation for the years ended December 31, 2021, 2020 and 2019.

The remaining milestone payments that the Company is eligible to receive have not been included in the transaction price as of December 31, 2021, as it is not considered probable that such payments will be received.

On May 31, 2018, the Company entered into a license agreement with Newsoara Biopharma Co., Ltd., (“Newsoara”) (the “Newsoara License Agreement”), under which Newsoara obtained an exclusive and sublicensable license to develop and commercialize the Company’s phosphodiesterase type 4 inhibitors (“PDE4”) program, including the compound HPP737, in China and other Pacific Rim territories (collectively, the “Newsoara License Territory”). Additionally, under the Newsoara License Agreement, the Company obtained a non-exclusive, sublicensable, royalty-free license to develop and commercialize certain Newsoara patent rights and know-how related to the Company’s PDE4 program for therapeutic uses in humans outside of the Newsoara License Territory. The Newsoara License Agreement was amended in 2020 to change certain future milestone payments and patent rights (the “First Newsoara Amendment”). Under the terms of the Newsoara License Agreement, Newsoara paid the Company an upfront cash payment of $2.0 million. During the year ended December 31, 2019, the Company received an additional payment of $1.0 million related to the satisfaction of a development milestone during the year. As amended, the Company is eligible to receive additional potential development, regulatory and sales-based milestone payments totaling up to $58.5 million. In addition, Newsoara is obligated to pay the Company royalty payments at high-single to low-double digit rates, based on tiers of annual net sales of licensed products. Such royalties will be payable on a licensed product-by-licensed product and country-by-country basis until the latest of expiration of the licensed patents covering a licensed product in a country, expiration of data exclusivity rights for a licensed product in a country or a specified number of years after the first commercial sale of a licensed product in a country.

Pursuant to the terms of the Newsoara License Agreement, the Company is required to provide technology transfer services for a defined period after the effective date. In accordance with ASC Topic 606, the Company identified all of the performance obligations at the inception of the Newsoara License Agreement. The significant obligations were determined to be the license and the technology transfer services. The Company has determined that the license and technology transfer services represent a single performance obligation because they were not capable of being distinct on their own. The transaction price has been fully allocated to this combined performance obligation and the related revenue was recognized during the year ended December 31, 2018.

During each of the years ended December 31, 2021, and 2019, the transaction price for this performance obligation was increased by $1.0 million due to the satisfaction of development milestones under the license agreement. These amounts were fully recognized as revenue during the years ended December 31, 2021, and 2019, as the related performance obligations have been fully satisfied.

On December 11, 2020, the Company entered into a license agreement with Anteris Bio, Inc. (“Anteris”) (the “Anteris License Agreement”), under which Anteris obtained a worldwide, exclusive and sublicensable license to develop and commercialize the Company’s Nrf2 activator, HPP971.

Under the terms of the Anteris License Agreement, Anteris paid the Company an initial license fee of $2.0 million. The Company is eligible to receive additional potential development, regulatory, and sales-based milestone payments totaling up to $151.0 million. Anteris is also obligated to pay vTv royalty payments at a double-digit rate based on annual net sales of licensed products. Such royalties will be payable on a licensed product-by-licensed product basis until the latest of expiration of the licensed patents covering a licensed product in a country, expiration of data exclusivity rights for a licensed product in a country, or a specified number of years after the first commercial sale of a licensed product in a country. As additional consideration, the Company received preferred stock representing a minority ownership interest in Anteris.

Pursuant to the terms of the Anteris License Agreement, the Company was required to provide technology transfer services for a 30 day period after the effective date. In accordance with ASC Topic 606, the Company identified all of the performance obligations at the inception of the Anteris License Agreement. The significant obligations were determined to be the license and the technology transfer services. The Company has determined that the license and technology transfer services represent a single performance obligation because they were not capable of being distinct on their own. The transaction price has been fully allocated to this combined performance obligation and consisted of the $2.0 million initial license payment as well as the fair value of the equity interest received in Anteris of $4.2 million. The revenue related to this performance obligation was fully recognized during the year ended December 31, 2020, as the technology transfer services were considered complete as of that date. No revenue was recognized related to the Anteris License Agreement during the year ended December 31, 2021.

In August 2017, the Company entered into the JDRF Agreement to support the funding of the Simplici-T1 Study, an adaptive Phase 1b/2 study to explore the effects of TTP399 in type 1 diabetics. The Company initiated this study in the fourth quarter of 2017. The JDRF Agreement was amended in June 2021 to provide additional funding for the Company’s mechanistic study exploring the effects of TTP399 on ketone body formation during a period of insulin withdrawal in people with type 1 diabetes. According to the terms of the JDRF Agreement, as amended, JDRF will provide research funding of up to $3.4 million based on the achievement of research and development milestones, with the total funding provided by JDRF not to exceed approximately one-half of the total cost of the project. Additionally, the Company has the obligation to make certain milestone payments to JDRF upon the commercialization, licensing, sale or transfer of TTP399 as a treatment for type 1 diabetes.

Payments that the Company receives from JDRF under this agreement are recorded as restricted cash and current liabilities and recognized as an offset to research and development expense, based on the progress of the project, and only to the extent that the restricted cash is utilized to fund such development activities. As of December 31, 2021, the Company had received funding under this agreement of $3.4 million, and research and development costs were offset by $3.4 million.

Contract liabilities related to the Company’s collaboration agreements consisted of the following (in thousands):

	December 31, 2021		December 31, 2020
Current portion of contract liabilities	$	35	$	31
Contract liabilities, net of current portion		—		1,009
Total contract liabilities	$	35	$	1,040

The change in the Company’s contract liabilities for the year ended December 31, 2021, was due to the recognition of amounts included in the contract liability at the beginning of the period caused by the reallocation of the transaction price in connection with the First Huandong Amendment discussed above.