On May 17, 2018, the Company amended the lease for its headquarters in Watertown, Massachusetts. The original five-year lease for approximately 13,650 square feet of combined office and laboratory space was set to expire in April 2019. Under the amendment, the Company leased an additional 6,590 square feet of rentable area of the building, with a commencement date of September 10, 2018. The amendment extended the term of the lease for the combined space through May 31, 2025. The landlord agreed to provide the Company a construction allowance of up to $670,750 to be applied toward the aggregate work completed on the total space. The Company has an option to further extend the term of the lease for one additional five-year period. Per the terms of the lease agreement, the Company does not have a residual value guarantee. The Company previously provided a cash-collateralized $150,000 irrevocable standby letter of credit as security for the Company’s obligations under the lease, which was extended through the period that is four months beyond the expiration date of the amended lease. The Company will also be required to pay its proportionate share of certain operating costs and property taxes applicable to the leased premises in excess of new base year amounts.

In July 2017, the Company leased approximately 3,000 square feet of office space in Basking Ridge, New Jersey under a lease term extending through June 2022, with two five-year renewal options at 95% of the then-prevailing market rates. In addition to base rent, the Company is obligated to pay its proportionate share of building operating expenses and real estate taxes in excess of base year amounts. In June 2018, the Company subleased an additional 1,381 square feet of adjoining space from Caladrius Biosciences, Inc. (“Caladrius”) through May 2022. The Chief Executive Officer of Caladrius is a director of the Company. Per the terms of the lease and sublease agreements, the Company does not have any residual value guarantees.

The Company identified and assessed the following significant assumptions in recognizing its ROU assets and corresponding lease liabilities:

As of June 30, 2019, the weighted average remaining term of the Company’s operating leases was 5.7 years and the lease liabilities arising from obtaining ROU assets reflect a weighted average discount rate of 12.5%. Maturities of lease liabilities due under these operating lease agreements as of June 30, 2019 are as follows (in thousands):

Remainder of 2019	$	425
2020		867
2021		889
2022		849
2023		815
Thereafter		1,176
Total lease payments		5,021
Less imputed interest		(1,431	)
Total operating lease liabilities		3,590
Less: current portion		441
Non-current portion	$	3,149

Operating lease expense recognized during the three and six months ended June 30, 2019 related to ROU assets were $213,000 and $427,000, respectively, excluding $9,000 and $18,000 of variable lease costs, respectively, and were included in general and administrative expense in the Company’s statement of comprehensive loss. Cash paid for amounts included in the measurement of operating lease liabilities were $205,000 and $383,000, respectively, for the three and six months ended June 30, 2019.

As previously disclosed in the Company’s Transition Report on Form 10-K for the six months ended December 31, 2018, and, under the previous lease accounting standard, ASC 840, Leases, the Company’s total future minimum lease payments under non-cancellable operating leases at December 31, 2018 were as follows (in thousands):

2019	$	826
2020		879
2021		895
2022		849
2023 and beyond		1,990
	$	5,439