21. Commitments and Contingencies Shelton Operating Lease As of December 31, 2015, the Company leases its operating facility located in Shelton, Connecticut. The lease agreement, as amended, requires monthly lease payments through October 13, 2017. At inception of the lease, the Company received an incentive allowance from the landlord of $2,127. The Company recorded the incentive allowance as leasehold improvements and deferred lease obligation. The Company is recording monthly rent expense associated with the lease on a straight-line basis over the ten-year minimum term of the lease reduced by the amortization of the deferred lease obligation over the same time period. As a result of this straight-line basis, deferred lease obligation includes $374 and $582 of unamortized incentive allowance plus $211 and $292 of accrued rent at December 31, 2015 and 2014, respectively. Total rent expense under the operating lease was $665, $643 and $616 for the years ended December 31, 2015, 2014 and 2013, respectively. Future minimum rental payments under the Shelton operating lease at December 31, 2015 are as follows: 2016 $ 913 2017 740 Total $ 1,653 In conjunction with the signing of the Shelton, Connecticut lease, the Company entered into a standby letter of credit agreement for $2,170, which expires on May 31, 2017 as a security deposit for the premises. In accordance with the terms of the lease, because no drawing was made against the standby letter of credit nor has any default under the operating lease occurred, the amount of the letter of credit was automatically reduced by $294 annually starting March 1, 2008 until the stated amount reached a balance of $700, which occurred in 2012. This standby letter of credit is secured with restricted cash (refer to Note 7, Restricted Cash ). In connection with the relocation of the Companys operating facility from Shelton to Stamford, Connecticut (see below), as of December 31, 2015, the Company was negotiating with the Shelton landlord regarding the Companys future obligatio