8.           Balance Sheet Detail:

Equipment and leasehold improvements consist of the following:

During the three months ended June 30, 2019 and 2018, the Company recorded depreciation and amortization expense of $0.1 million, respectively. During the six months ended June 30, 2019 and 2018, the Company recorded depreciation and amortization expense of $0.3 million and $0.2 million, respectively. Depreciation and amortization expense are included in selling, general and administrative expense.

In limited circumstances, the Company offers extended payment terms to customers for periods of 12 to 48 months. The related customer receivables are classified as accounts receivable long-term and discounted to their present value at prevailing market rates at the time of sale. In subsequent periods, the accounts receivable is increased to the amounts due and payable by the customers through the accretion of interest income on the unpaid accounts receivable due in future years. The amounts under these long-term accounts receivable due within one year are reclassified to the current portion of accounts receivable. At times the Company sells receivables to a financial institution on a non-recourse basis for cash, less a discount. The net proceeds from such sales are included in the operating section of the statement of cash flows as changes in accounts receivable. Accounts receivable long term, net consists of the following:

The undiscounted cash flows to be received by the Company relating to these accounts receivable long-term will be $6.4 million, $2.5 million and $0.3 million during the 12-month periods ending June 30, 2020, 2021 and 2022, respectively.

Accounts payable and accrued expenses consist of the following: