The Company adopted Topic 842 on January 1, 2019. Topic 842 allows the Company to elect a package of practical expedients, which include: (i) an entity need not reassess whether any expired or existing contracts are or contain leases; (ii) an entity need not reassess the lease classification for any expired or existing leases; and (iii) an entity need not reassess any initial direct costs for any existing leases. Another practical expedient allows the Company to use hindsight in determining the lease term when considering lessee options to extend or terminate the lease and to purchase the underlying asset. The Company has elected to utilize this package of practical expedients and has not elected the hindsight methodology in its implementation of Topic 842.

The Company elected to adopt this standard using the optional modified retrospective transition method and recognized a cumulative-effect adjustment to the condensed consolidated balance sheet on the date of adoption. Comparative periods have not been restated. With the adoption of Topic 842, the Company’s condensed consolidated balance sheet now contains the following line items: Right-of-use assets, Operating lease liabilities—short-term and Operating lease liabilities—long-term.

The Company determined that it held the following significant operating leases of office and laboratory space as of January 1, 2019:

The Company also has two additional operating leases that are included in its lease accounting but are not considered significant.

The Company has elected to not recognize right-of-use assets and lease liabilities arising from short-term leases, which are leases that, at the commencement date, have a lease term of 12 months or less and do not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

As all the existing leases subject to the new lease standard were previously classified as operating leases by the Company, they were similarly classified as operating leases under the new standard. The Company has determined that the identified operating leases did not contain non-lease components and require no further allocation of the total lease cost. Additionally, the agreements in place did not contain information to determine the rate implicit in the leases. As such, the Company calculated the incremental borrowing rate based on the assumed remaining lease term for each lease in order to calculate the present value of the remaining lease payments. At March 31, 2019, the weighted average incremental borrowing rate and the weighted average remaining lease term for the operating leases held by the Company were 4.46% and 4.1 years, respectively.

As of March 31, 2019, right-of-use assets and liabilities arising from operating leases were $18.0 million and $19.8 million, respectively. During the three months ended March 31, 2019, cash paid for amounts included for the measurement of lease liabilities was $2.3 million and the Company recorded operating lease expense of $2.1 million.

Future lease payments under non-cancelable leases as of March 31, 2019 and December 31, 2018:

	March 31,			December 31,
(In thousands)	2019			2018
2019	$	6,806		$	9,394
2020		8,652			10,717
2021		2,520			4,706
2022		500			2,455
2023		509			2,389
Thereafter		3,100			23,940
Total lease payments	$	22,087		$	53,601
Less: imputed interest		(2,272	)		—
Total operating lease liabilities	$	19,815		$	53,601

In March 2018, the Company entered into a lease agreement for approximately 220,000 square feet of office and laboratory space located in a building that is being built at 900 Winter Street, Waltham, Massachusetts (“900 Winter Street”). The Company plans to occupy the premises in early 2020. The initial term of the lease shall commence on the earlier of: (i) the Delivery Date (defined as (a) the later of January 20, 2020, or (b) the date on which the landlord substantially completes its work in accordance with the terms of the lease), or (ii) the date the Company enters into possession of all or any substantial portion of 900 Winter Street for the conduct of its business (the “Commencement Date”). The initial lease term expires on the last day of the calendar month in which the fifteenth (15^th) anniversary of the Commencement Date occurs, with an option to extend for an additional ten (10) years.

As the Company (a) does not have the right to obtain or control the leased premises during the construction period; (b) does not have the right of payment for the partially constructed assets and, thus, could be potentially leased to another tenant; and (c) does not legally own or control the land on which the property improvements are being constructed, it was not included as a right-of-use asset at March 31, 2019. Additionally, the future lease payments, outlined above, included the 900 Winter Street payments as of December 31, 2018; these payments are not included in the table under Topic 842.