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.

On January 17, 2018, the Company entered into an amendment to the Original Lease (the “Amendment”). The Amendment makes certain modifications to the Original Lease, including the addition of approximately 7,800 square feet of office space in the same building (the “Expansion Premises”) 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.

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 with a term beginning in June 2020 (the “Second Expansion Premises”), and (ii) an extension of the expiration date of all existing leases 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 Second 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 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. This lease was terminated in August 2019.

For the three months ended March 31, 2020, the components of operating lease expense were as follows (in thousands):

		Three Months Ended
Operating lease expense	Statement of Operations Location	March 31, 2020
Fixed operating lease expense	Research and development expense		164
	General and administrative expense		86

Variable operating lease expense	Research and development expense		17
	General and administrative expense		9

Total operating lease expense			276

Supplemental cash flow information related to the Company’s operating leases for the three months ended March 31, 2020, was as follows (in thousands):

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 March 31, 2020 and December 31, 2019. As this equipment was fully paid in 2018, there is no corresponding lease liability as of March 31, 2020.

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 March 31, 2020 (in thousands, except for the weighted average remaining lease term and the weighted average discount rate):

Lease Assets and Liabilities	Classification	March 31, 2020
Assets
Operating	Operating lease right of use assets	$	4,765
Financing	Property and equipment, net		937
Total leased assets		$	5,702

Liabilities
Current
Operating	Operating lease liabilities	$	932
Non-Current
Operating	Non-current operating lease liabilities		4,521
Total lease liabilities		$	5,453

Weighted average remaining lease term		7 years
Weighted average discount rate			10.3	%

The following table presents the maturity of the Company’s operating lease liabilities as of March 31, 2020 (in thousands):

Years Ending December 31,
2020 (remainder)	$	696
2021		943
2022		1,061
2023		1,076
2024		1,092
2025		1,108
Thereafter		1,862
Total future minimum lease payments		7,838
Less imputed interest		(2,385	)
Total operating lease liabilities	$	5,453

Total minimum future lease payments of approximately $4.3 million for a lease that has not commenced as of March 31, 2020 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 the second half of 2020, with a lease term of 7 years.