Supporting Financial Information | Supporting Financial Information Accounts receivable (in thousands) December 31, September 30, Ref 2019 2019 Billed receivables $ 23,261 $ 18,924 Contract assets 4,734 4,302 Total accounts receivable 27,995 23,226 Less: Allowance for doubtful accounts (a) — — Accounts receivable, net $ 27,995 $ 23,226 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, 2019 or September 30, 2019 . Other current assets (in thousands) December 31, September 30, 2019 2019 Prepaid insurance and benefits $ 619 $ 495 Other receivables 306 301 Other prepaid expenses 1,007 1,035 Other current assets $ 1,932 $ 1,831 Equipment and improvements, net (in thousands) December 31, September 30, Ref 2019 2019 Furniture and equipment $ 1,262 $ 1,262 Computer equipment 1,171 1,043 Computer software 4,019 3,985 Leasehold improvements 1,595 1,595 Total equipment and improvements 8,047 7,885 Less accumulated depreciation and amortization (3,196 ) (2,542 ) Equipment and improvements, net $ 4,851 $ 5,343 Ref (a): Depreciation expense was $0.7 million and $0.1 million for the three months ended December 31, 2019 and 2018, respectively. Intangible assets (in thousands) December 31, September 30, Ref 2019 2019 Intangible assets (a) Customer contracts and related customer relationships $ 45,600 $ 45,600 Covenants not to compete 480 480 Trade name 2,109 2,109 Total intangible assets 48,189 48,189 Less accumulated amortization Customer contracts and related customer relationships (7,730 ) (6,590 ) Covenants not to compete (176 ) (164 ) Trade name (279 ) (227 ) Total accumulated amortization (8,185 ) (6,981 ) Intangible assets, net $ 40,004 $ 41,208 Ref (a): Intangible assets subject to amortization. The intangibles are amortized on a straight-line basis over their estimated useful lives of 10 years . The total amount of amortization expense was $1.2 million and $0.4 million for the three months ended December 31, 2019 and 2018 . Estimated amortization expense for future years: (in thousands) Remaining Fiscal 2020 $ 3,614 Fiscal 2021 4,819 Fiscal 2022 4,819 Fiscal 2023 4,819 Fiscal 2024 4,819 Thereafter 17,114 Total amortization expense $ 40,004 Accounts payable, accrued expenses and other current liabilities (in thousands) December 31, September 30, 2019 2019 Accounts payable $ 9,908 $ 10,054 Accrued benefits 2,278 2,252 Accrued bonus and incentive compensation 714 1,951 Accrued workers' compensation insurance 4,280 4,007 Other accrued expenses 1,651 2,369 Accounts payable, accrued expenses, and other current liabilities $ 18,831 $ 20,633 Debt obligations (in thousands) December 31, September 30, 2019 2019 Bank term loan $ 56,000 $ 56,000 Less unamortized deferred financing cost (2,208 ) (2,371 ) Net bank debt obligation 53,792 53,629 Less current portion of term loan debt obligations — — Long-term portion of bank debt obligation $ 53,792 $ 53,629 Interest expense (in thousands) Three Months Ended December 31, Ref 2019 2018 Interest expense (a) $ (852 ) $ (104 ) Amortization of deferred financing costs (b) (210 ) (73 ) Other income (expense), net (c) 121 — Interest expense, net $ (941 ) $ (177 ) Ref (a): Interest expense on borrowing Ref (b): Amortization of expenses related to term loan and revolving line of credit Ref (c): Gain on lease modification due to a lease amendment |