12. Commitments and Contingencies Operating leases In January 2007, the Company entered into a lease for 8,100 square feet of office and lab space in Newtown, Pennsylvania, and in October 2009, the Company and the landlord amended the lease to add three additional one-year options to extend the lease term. In November 2013 the Company renewed the lease for the period April 1, 2014 to March 31, 2015, for rent of $11,000 per month. In December 2014 the Company renewed the lease for the period April 1, 2015 to March 31, 2016, for rent of $11,500 per month. In November 2015 the Company renewed the lease for the period April 1, 2016 to March 31, 2017, for rent of $11,900 per month. In September 2012, the Company sub-leased an additional 1,356 square feet of office space. The lease was renewed through February 28, 2017 for rent of $1,600 per month. In February 2017, the Company combined the leases and renewed the lease for the combined space for the period March 1, 2017 to February 28, 2018, for rent of $13,800 per month. The Company renewed the lease for the combined space for the period March 1, 2018 to February 28, 2019, for rent of $14,200 per month. The Company renewed the lease for the combined space for the period March 1, 2019 to February 28, 2020, for rent of $14,700 per month. The Company renewed the lease for the combined space for the period March 1, 2020 to February 28, 2021, for rent of $15,100 per month. Future minimum lease payments under these non-cancellable leases having terms in excess of one year as of December 31, 2019 are as follows: December 31, 2019 2020 $ 180,000 2021 30,000 Total minimum lease payments $ 210,000 Net rent expense was $158,000 and $165,000 for the years ended December 31, 2019 and 2018, respectively. Employment agreements The Company has entered into employment agreements with certain of its executives. The agreements provide for, among other things, salary, bonus and severance payments.