In August 2015, the Company entered into an operating lease agreement with U.S. REIF Central Plaza Massachusetts, LLC (the “Landlord”) with respect to its corporate headquarters located at 675 Massachusetts Avenue, Cambridge, Massachusetts (the “Original Lease”). The term of the Original Lease commenced in January 2016 and was scheduled to expire in December 2020. Under the terms of the Original Lease, the Company provided a security deposit of $0.2 million to the Landlord, which is included in long-term assets in the accompanying condensed consolidated balance sheets. The Original Lease provided for annual rent escalations as well as tenant incentives in the amount of $0.7 million, of which $0.3 million would be reimbursed to the Landlord over the initial term of the Original Lease. In determining its ROU assets as of January 1, 2019, the Company reduced the amount of ROU assets by $0.2 million, which was the remaining balance of lease incentives received from the Landlord as of that date. The lease does not include any restrictions or covenants that had to be accounted for under the lease guidance.

On January 17, 2018, the Company entered into an amendment to the Original Lease (the “Amendment”). The Amendment made certain modifications to the Original Lease, including the addition of approximately 7,800 square feet of office space in the same building and an extension of the expiration date of the Original Lease to seven years, or December 2025. The Amendment also provided for $0.4 million from the Landlord for leasehold improvements on the Expansion Premises. In determining its ROU assets as of January 1, 2019, the Company reduced the amount of ROU assets by $0.4 million, which was the remaining balance of lease incentives received from the Landlord as of that date. The lease does not include any restrictions or covenants that had to be accounted for under the lease guidance.

On December 16, 2019, the Company entered into a second amendment to the Original Lease and the Amendment (the “Second Amendment”). The Second Amendment made certain modifications, including (i) the addition of approximately 7,800 square feet of office space in the same building (the “Expansion Premises”) with a term beginning on June 2020 and expiring on May 2027, and (ii) an extension of the expiration date of the lease through May 2027.

Under the Second Amendment, the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord. These renewal options were not included in the calculation of the operating lease assets and operating lease liabilities, as the renewal is not reasonably certain. The Second Amendment provides for annual base rent for the Expansion Premises of approximately $0.6 million in the first year of the Lease Term, which increases on an annual basis to approximately $0.7 million in the final year of the Lease Term, and annual base rent during the Option Terms to be calculated based on the Landlord’s good faith determination of 100% of the fair market rate for such Option Terms. The Company is also obligated to pay the Landlord certain costs, taxes and operating expenses, subject to certain exclusions. The Second Amendment also provides for $0.4 million from the Landlord for leasehold improvements on the Expansion Premises.

In July 2016, the Company entered into an agreement to lease laboratory space through November 30, 2019 from a sublessor, which required annual lease payments of $0.3 million, subject to certain escalations.

For the year ended December 31, 2019, the components of operating lease expense were as follows (in thousands):


Operating lease expense	Statement of Operations Location	December 31, 2019
Fixed operating lease expense	Research and development expense		601
	General and administrative expense		641

Variable operating lease expense	Research and development expense		56
	General and administrative expense		181

Total operating lease expense		$	1,479

Supplemental cash flow information related to the Company’s operating leases for the year ended December 31, 2019, was as follows (in thousands):

	December 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	1,234
Non cash amounts resulting from the measurement of the lease liabilities:
Right of use asset and lease obligation recorded upon amendment of lease agreements	$	1,038

As part of our agreement with Meiji Seika Pharma Co. Ltd. (“Meiji”), the Company paid Meiji approximately $1.6 million during the three months ended December 31, 2018, related to fixed assets which will be used in manufacturing related activities at Meiji. The Company determined this equipment to be an embedded finance lease and has been capitalized as property and equipment in the condensed consolidated balance sheet as of December 31, 2019 and 2018. As this equipment was fully paid in 2018, there is no corresponding lease liability as of December 31, 2019.

The following table presents the lease balances within the condensed consolidated balance sheet, weighted average remaining lease term, and the weighted average discount rates related to the Company’s operating and finance leases as of December 31, 2019 (in thousands, except for the weighted average remaining lease term, which is in years, and the weighted average discount rate):

Lease Assets and Liabilities	Classification	December 31, 2019
Assets
Operating	Operating lease right of use assets	$	4,875
Financing	Property and equipment, net		1,004
Total leased assets		$	5,879

Liabilities
Current
Operating	Operating lease liabilities	$	928
Non-Current
Operating	Non-current operating lease liabilities		4,617
Total lease liabilities		$	5,545

Weighted average remaining lease term			7
Weighted average discount rate			10	%

The following table presents the maturity of the Company’s operating lease liabilities as of December 31, 2019 (in thousands):

Years Ending December 31,
2020	$	928
2021		943
2022		1,061
2023		1,076
2024		1,092
Thereafter		2,969
Total future minimum lease payments		8,069
Less imputed interest		(2,524	)
Total operating lease liabilities	$	5,545

The following table summarizes the future minimum payments due for the Company’s operating leases under the prior lease guidance for each of the next five years and total thereafter as of December 31, 2018 (in thousands):

Years Ending December 31,
2019	$	1,361
2020		1,054
2021		995
2022		1,107
2023		1,123
Thereafter		2,246
	$	7,886

Total minimum future lease payments of approximately $4.3 million for a lease that has not commenced as of December 31, 2019 is not included in the table above or in the lease liability in consolidated financial statements, as the Company does not yet have control of the underlying asset. The lease is expected to commence in June 2020 with a lease term of 7 years.