Commitments and Contingencies Operating Lease Obligations : A Lexicon subsidiary leases laboratory and office space in Hopewell, New Jersey under an amended lease agreement which previously had an expiration date in June 2018. In March 2015, the subsidiary entered into a termination agreement whereby the lease will terminate in June 2015 and a separate lease agreement, the term of which begins in June 2015 and terminates in December 2022. Rent expense is recognized on a straight-line basis over the lease term. Lexicon is the guarantor of the obligations of its subsidiary under these lease agreements. The maximum potential amount of future payments the Company could be required to make under these agreements is $4.5 million as of March 31, 2015 . Under its current lease, the Company is required to maintain restricted investments to collateralize a standby letter of credit for this lease. The Company had $0.4 million and $0.4 million in restricted investments as collateral as of March 31, 2015 and December 31, 2014 , respectively. Additionally, Lexicon leases certain equipment under operating leases. Legal Proceedings. Lexicon is from time to time party to claims and legal proceedings that arise in the normal course of its business and that it believes will not have, individually or in the aggregate, a material adverse effect on its results of operations, financial condition or liquidity.