The Company conducts its operations in leased office facilities under various noncancelable operating lease agreements that expire through December 2029.

On October 26, 2017, the Company and Hines Global REIT Riverside Center, LLC (“Hines”) entered into a Third Amendment (the “Third Amendment”) to the lease agreement for office space in Newton, Massachusetts, dated as of August 4, 2009, by and between the Company and MA-Riverside Project, L.L.C. (predecessor-in-interest to Hines) as amended (the “Newton Lease”). The Third Amendment extends the lease term to December 31, 2029 and preserves the Company’s option to extend the term for an additional five-year period subject to certain terms and conditions set forth in the Newton Lease. The Third Amendment reduces the rentable space from approximately 110,000 square feet to approximately 74,000 square feet effective January 1, 2018 and provides the Company with a one-time cash allowance of up to $3.3 million, which may be used by the Company for any purpose. Beginning on January 1, 2018, base monthly rent under the Third Amendment will be $0.3 million. The base rent will increase biennially at a rate averaging approximately 1% per year, beginning on January 1, 2020. The Company remains responsible for certain other costs under the Third Amendment, including operating expense and taxes.

The Newton Lease contains rent concessions, which the Company is receiving over the life of the Newton Lease. Certain of the Company’s operating leases include lease incentives and escalating payment amounts and are renewable for varying periods. The Company is recognizing the related rent expense on a straight-line basis over the term of each lease, taking into account the lease incentives and escalating lease payments. Total rent expense under the Company’s leases was approximately $4.0 million, $4.5 million, and $4.4 million for the years ended December 31, 2018, 2017, and 2016, respectively.

Future minimum lease payments under the Company’s noncancelable operating leases at December 31, 2018 are as follows:

Years Ending December 31:	Minimum Lease Payments
2019	$	4,180
2020		3,629
2021		3,721
2022		3,397
2023		3,397
Thereafter		21,267
	$	39,591

From time to time and in the ordinary course of business, the Company may be subject to various claims, charges, and litigation. At December 31, 2018 and 2017, the Company did not have any pending claims, charges, or litigation that it expects would have a material adverse effect on its consolidated financial position, results of operations, or cash flows.