Commitments and Contingencies

Manufacturing and Supply Agreements

Matricel — In October 2015, the Company signed a long-term supply agreement with Matricel GmbH for the ACI-Maix collagen membrane used in the manufacture of MACI. Matricel supplied ACI-Maix membranes used in the production of MACI when it was previously marketed outside the U.S. by Genzyme Corporation, a Sanofi company. The Company and Matricel amended the agreement on March 17, 2018. Under the agreement, the Company has committed to purchase annually approximately $0.6 million per year. For the years ended December 31, 2016, 2017 and 2018, the Company has fulfilled this commitment. The agreement is effective until December 31, 2022 and contains a 5-year renewal option by the Company and an additional 5-year automatic renewal, unless otherwise terminated.

Manufacture, Supply and Other Agreements — The Company has entered into various agreements relating to the manufacture of its products and the supply of certain components. If the manufacturing or supply agreements expire or are otherwise terminated, the Company may not be able to identify and obtain ancillary materials that are necessary to develop its products and such expiration and termination could have a material effect on the Company’s business.

Contractual Obligations

The Company leases facilities in Ann Arbor, Michigan and Cambridge, Massachusetts. In March 2016, the Company amended its current lease in Cambridge to extend the terms until February 2022 and have the right to extend until February 2027, subject to certain conditions. The Cambridge facilities include clean rooms, laboratories for MACI and Epicel manufacturing and office space. It is probable the Company will exercise its right to extend the lease. Under the amendment, the landlord will contribute approximately $2.0 million toward the cost of tenant improvements. The contribution toward the cost of tenant improvements is recorded as deferred rent on the Company's consolidated balance sheet and is amortized to our consolidated statement of operations as reductions to rent expense over the lease term. Through December 31, 2018, the Company has recorded tenant improvements of $1.9 million. In addition to the property leases, the Company also pays for use of an offsite warehouse space, and leases various vehicles and computer equipment.

Future minimum payments related to our operating and capital leases, and contractual obligations including interest on outstanding term loans are as follows:



			Payments Due by Period
Contractual Obligations	Total		2019		2020		2021		2022		2023		More than 5 Years
Operating leases	$	15,386	$	4,879	$	4,719	$	4,754	$	966	$	68	$	—
Purchase commitments	2,761		741		711		674		635		—		—
Capital leases	205		41		41		41		41		41		—
Total	$	18,352	$	5,661	$	5,471	$	5,469	$	1,642	$	109	$	—

Rent expense for the years ended December 31, 2018, 2017 and 2016, was $5.5 million, $5.6 million and $4.8 million, respectively.