Commitments and Contingencies Legal Proceedings The Company periodically becomes subject to legal proceedings and claims arising in connection with its business. The ultimate legal and financial liability of the Company in respect to all proceedings, claims and lawsuits, pending or threatened, cannot be estimated with any certainty. As of the date of this report, the Company is not aware of any proceeding, claim or litigation, pending or threatened, that could, individually or in the aggregate, have a material adverse effect on the Companys business, operating results, financial condition and/or liquidity. Operating Leases The following is a summary of the Companys long-term contractual cash obligations as of December 31, 2018 (in thousands): Operating Lease(1) 2019 $ 653 2020 663 2021 674 2022 686 2023 172 Thereafter  Total $ 2,848 (1) Operating lease obligations include the lease agreement the Company entered into on August 6, 2015 for office space in Warren, New Jersey. Rent expense is calculated on the straight-line basis and amounted to approximately $0.7 million , $0.7 million , $0.4 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Royalty payments and success-based milestones associated with the Companys license and supply agreements with Ikaria have not been included in the above table of contractual obligations as the Company cannot reasonably estimate if or when they will occur. License Agreement with Ikaria In February 2014, the Company entered into a cross-license, technology transfer and regulatory matters agreement with a subsidiary of Ikaria. Pursuant to the terms of the license agreement, Ikaria granted to the Company a fully paid-up, non-royalty-bearing, exclusive license under specified intellectual property rights controlled by Ikaria to engage in the development, manufacture and commercialization of nitric oxide, devices to deliver nitric oxide and related services for or in connection with out-patient, chronic treatment of patients who have PAH, PH-COPD or PH associated with idiopathic pulmonary fibrosis, or PH-IPF. Pursuant to the terms of the license agreement, the Company granted Ikaria a fully paid-up, non-royalty-bearing, exclusive license under specified intellectual property rights that the Company controls to engage in the development, manufacture and commercialization of products and services for or used in connection with the diagnosis, prevention or treatment, whether in- or out-patient, of certain conditions and diseases other than PAH, PH-COPD or PH-IPF and for the use of nitric oxide to treat or prevent conditions that are primarily managed in the hospital. The Company agreed that, during the term of the license agreement, it will not, without the prior written consent of Ikaria, grant a sublicense under any of the intellectual property licensed to the Company under the license agreement to any of its affiliates or any third party, in either case, that directly or indirectly competes with Ikarias nitric oxide business. In July 2015, the Company and Ikaria entered into an amendment to the license agreement to expand the scope of the Companys license to allow the Company to develop its INOpulse program for the treatment of three additional indications: chronic thromboembolic PH, or CTEPH, PH associated with sarcoidosis and PH associated with pulmonary edema from high altitude sickness. Subject to the terms set forth therein, the amendment to the license agreement also provides that the Company will pay Ikaria a royalty equal to 5% of net sales of any commercialized products for the three additional indications. In November 2015, the Company entered into an amendment to its exclusive cross-license, technology transfer and regulatory matters agreement with Ikaria that included a royalty equal to 3% of net sales of any commercial products for PAH. In April 2018, we expanded the scope of our license from PH-IPF to PH in patients with Pulmonary Fibrosis (PH-PF), which includes idiopathic interstitial pneumonias, chronic hypersensitivity pneumonitis, occupational and environmental lung disease, with a royalty equal to 1% of net sales of any commercial products for PH-PF. Agreements Not to Compete In September 2013, October 2013 and February 2014, the Company entered into an agreement not to compete with Ikaria, each of which was amended in July 2015, or, collectively, the agreements not to compete. Pursuant to the agreements not to compete, as amended, the Company agreed not to engage, anywhere in the world, in any manner, directly or indirectly, until the earlier of five years after the effective date of such agreement not to compete amendments or the date on which Ikaria and all of its subsidiaries are no longer engaged in such business as specified in the agreements. In the course of its normal business operations, the Company also enters into agreements with contract service providers and others to assist in the performance of its research and development and manufacturing activities. The Company can elect to discontinue the work under these contracts and purchase orders at any time with notice, and such contracts and purchase orders do not contain minimum purchase obligations. In August 2009, the Company entered into a license agreement with BioLineRx Ltd. and BioLine Innovations Jerusalem L.P., which are referred to collectively as BioLine, under which the Company obtained an exclusive worldwide license to BCM. In July 2018, the Company informed BioLineRx Ltd., from whom it in-licensed the BCM technology, on its decision to discontinue further development and terminate the License and Commercialization Agreement.