13. Commitments and Contingencies The Company has concurrent leases for its current headquarters office and lab space that extend through April 2020. The Company may elect to extend the term of the leases for an additional five-year term. The leases provide for a tenant improvement allowance of approximately $2.1 million in aggregate. During the three months ended March 31, 2018, none of the allowance was utilized. During the three months ended March 31, 2017, $50,000 of the allowance was utilized and is included in fixed assets and deferred rent. As of March 31, 2018, $0.4 million is available for tenant improvements. The Company has entered into a new lease agreement, effective February 27, 2018, with Rockside-700 LLC, for its new headquarters. The term of the new lease commences upon the Companys substantial completion of the initial buildout of the premises, but in no event later than July 10, 2019, and shall continue until April 30, 2033, unless earlier terminated in accordance with the terms of the new lease (the Lease Term). Under the new lease, the Company has the option to extend the Lease Term for two additional five-year periods. The new lease provides for a tenant improvement allowance of approximately $8.9 million in aggregate. The Company has the right to terminate the lease if, by September 30, 2018, the landlord fails to obtain certain site approval pre-requisites per the lease agreement. As of March 31, 2018, none of the tenant improvement allowance has been received and the full amount of the allowance is available for tenant improvements. Rent expense for the leased facilities and leased vehicles was approximately $0.9 million and $0.7 million for the three months ended March 31, 2018 and 2017, respectively. Future minimum lease payments under non-cancelable operating leases as of March 31, 2018 are as follows, in thousands of dollars, unaudited: Year ending December 31: 2018 (remaining) 2,555 2019 3,363 2020 2,665 Thereafter 301 $ 8,884 The Company has obtained exclusive licenses from third p