17. Commitments and Contingencies

In March 2007, a lease agreement for an unlimited period starting in December 2007 was entered into for the use of business and research premises in Vienna. The contract has a six-month notice period and can be terminated every quarter end.

In July 2015, a lease agreement was entered into for the use of approximately 15,000 square feet of office space in King of Prussia, PA, with the lease term continuing until December 2023 with no renewal options.

In February 2018, a lease agreement starting in March 2018 was entered into for the use of office space in Dublin and has a month-to-month term.

We also enter into lease agreements for equipment such as copiers and printers.

Lease expense was $1.3 million, $1.3 million, and $1.4 million for the years ended December 31, 2016, 2017 and 2018, respectively.

Future minimum contractual obligations and commitments at December 31, 2018 are as follows:


	Year ending December 31,
(in thousands)	Total		2019		2020		2021		2022		2023		Thereafter
Operating lease obligations	$	3,507	$	1,456	$	507	$	515	$	522	$	507	$	—
Other contractual commitments		10,166		10,166		—		—		—		—		—
Total	$	13,673	$	11,622	$	507	$	515	$	522	$	507	$	—

In addition to the agreements described above, the Company has other contractual commitments related primarily to contracts entered into with contract research organizations and contract manufacturing organizations in connection with the conduct of clinical trials and other research and development activities. The estimated payments to the service providers included in the table above are based solely on the estimated work to be performed by them to complete the trials and other activities along with the anticipated achievement of milestones included within the agreements. Also, some of these contracts are subject to early termination clauses exercisable at the discretion of the Company. The Company is not obligated to make minimum required payments under these service agreements.

The Company has no contingent liabilities in respect of legal claims arising in the ordinary course of business.