Property and equipment consisted of the following:

Depreciation expense was $132,337 and $126,641 for the three months ended September 30, 2018 and 2017, respectively and $338,651 and $191,093 for the nine months ended September 30, 2018 and 2017, respectively. In the first quarter of 2018, the Company wrote off $191,244 of fully amortized leasehold improvements related to the termination of the September 2016 Amendment in February 2018 as discussed in Note 6.

On December 30, 2015, the Company entered into a lease agreement for a copier machine. The cost of the machine was approximately $12,000 and is included in office furniture and equipment category in the table above. The lease payments commenced when the machine was placed in service in January 2016. The machine is being amortized over the life of the lease, which is for a three-year term and includes a bargain purchase option at the end of the term. See Note 6 for details of this capital lease commitment.