Supporting Financial Information | Supporting Financial Information Accounts receivable (in thousands) December 31, September 30, Ref 2018 2018 Billed receivables $ 13,644 $ 10,066 Contract assets 479 214 Total accounts receivable 14,123 10,280 Less: Allowance for doubtful accounts (a) — — Accounts receivable, net $ 14,123 $ 10,280 Ref (a): Accounts receivable are non-interest bearing, unsecured and carried at net realizable value. We evaluate our receivables on a quarterly basis and determine whether an allowance is appropriate based on specific collection issues. No allowance for doubtful accounts was deemed necessary at either December 31, 2018 or September 30, 2018 . Other current assets (in thousands) December 31, September 30, 2018 2018 Prepaid insurance and benefits $ 692 $ 401 Other receivables and prepaid expenses 575 359 Other current assets $ 1,267 $ 760 Equipment and improvements, net (in thousands) December 31, September 30, Ref 2018 2018 Furniture and equipment $ 326 $ 326 Computer equipment 751 751 Computer software 1,731 1,731 Leasehold improvements 66 66 Total fixed assets 2,874 2,874 Less accumulated depreciation and amortization (1,430 ) (1,308 ) Equipment and improvements, net (a) $ 1,444 $ 1,566 Ref (a): Equipment and improvements are stated at cost. Depreciation and amortization are provided using the straight-line method over the estimated useful asset lives ( 3 to 7 years) and the shorter of the initial lease term or estimated useful life for leasehold improvements. Maintenance and repair costs are expensed as incurred. Depreciation expense was $0.1 million and $0.1 million for the three months ended December 31, 2018 and 2017 . Intangible Assets (in thousands) December 31, September 30, Ref 2018 2018 Intangible assets (a) Customer contracts and related customer relationships $ 16,626 $ 16,626 Covenants not to compete 480 480 Trade name 517 517 Intangible assets 17,623 17,623 Less accumulated amortization Customer contracts and related customer relationships (4,434 ) (4,018 ) Covenants not to compete (128 ) (116 ) Trade name (137 ) (124 ) Total accumulated amortization (4,699 ) (4,258 ) Intangible assets, net $ 12,924 $ 13,365 Ref (a): Intangible assets subject to amortization. The intangibles are amortized on a straight-line basis over their estimated useful lives of 10 years . Total amount of amortization expense was $0.4 million and $0.4 million for the three months ended December 31, 2018 and 2017 . Estimated amortization expense for future years: (in thousands) Remaining Fiscal 2019 $ 1,321 Fiscal 2020 1,762 Fiscal 2021 1,762 Fiscal 2022 1,762 Fiscal 2023 1,762 Thereafter 4,555 Total amortization expense $ 12,924 Accounts payable, accrued expenses and other current liabilities (in thousands) December 31, September 30, 2018 2018 Accounts payable $ 3,853 $ 3,393 Accrued benefits 1,539 2,060 Accrued bonus and incentive compensation 525 2,191 Accrued workers compensation insurance 3,046 2,642 Other accrued expenses 955 664 Accounts payable, accrued expenses, and other current liabilities $ 9,918 $ 10,950 Debt obligations (in thousands) December 31, September 30, Ref 2018 2018 Bank term loan (a) $ 7,395 $ 7,708 Less unamortized debt issuance costs (677 ) (750 ) Net bank debt obligation 6,718 6,958 Less current portion of bank debt obligations — — Long term portion of bank debt obligation $ 6,718 $ 6,958 Ref (a): Maturity of the bank debt obligation as follows, in thousands: Fiscal 2019 $ — Fiscal 2020 1,562 Fiscal 2021 5,833 Total bank debt obligation $ 7,395 Interest expense (in thousands) Three Months Ended December 31, Ref 2018 2017 Interest expense (a) $ (104 ) $ (219 ) Amortization of debt financing costs as interest expense (b) (73 ) (65 ) Other income (expense), net — 6 Interest expense, net $ (177 ) $ (278 ) Ref (a): Interest expense on borrowing Ref (b): Amortizations of expenses related to securing financing |