Summary of Significant Accounting Policies Unaudited Interim Financial Information	6 Months Ended
	Mar. 31, 2026
Accounting Policies [Abstract]
Summary of Significant Accounting Policies Unaudited Interim Financial Information	2. Summary of Significant Accounting Policies Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and the rules and regulations of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In management's opinion, all adjustments, consisting of normal, recurring adjustments considered necessary for a fair presentation, have been included, and intercompany transactions and accounts have been eliminated in consolidation. The information disclosed in the notes to the condensed consolidated financial statements for these periods is unaudited. Operating results for the three and six months ended March 31, 2026, are not necessarily indicative of the results that may be expected for the year ending September 30, 2026, or for any future period. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect amounts in the condensed consolidated financial statements and accompanying notes. For the three and six months ended March 31, 2026, these estimates required the Company to make assumptions about disruptions to macroeconomic conditions such as the impact of ongoing international armed and geopolitical conflicts, tariffs, global trade, market volatility and uncertainty and, in turn, the Company's results of operations. The Company will continue to update its assumptions as conditions change. Actual results could differ significantly from those estimates. Contract Assets and Liabilities Contract assets reflect an estimate of expenses that will be reimbursed upon settlement with a seller. The contract asset balance was $2.2 million as of March 31, 2026, and $1.3 million as of September 30, 2025, and is included in the line-item Prepaid expenses and other current assets on the Condensed Consolidated Balance Sheets. Contract liabilities reflect obligations to provide services for which the Company has already received consideration, and generally arise from up-front payments received in connection with our Machinio and Software Solutions subscription services. The contract liability balance was $5.1 million as of March 31, 2026, and $5.1 million as of September 30, 2025, and is included in the line-item Deferred revenue on the Condensed Consolidated Balance Sheets. Of the September 30, 2025 contract liability balance, $4.0 million was earned as other fee revenue during the six months ended March 31, 2026. For the Company's Machinio & Software Solutions segment, the performance obligation has been identified as the stand ready obligation to provide access to subscription services offered by our Machinio and Software Solutions businesses, which are satisfied over time and recognized as other fee revenues in the line-item Consignment and other fee revenues on the Condensed Consolidated Statements of Operations. As of March 31, 2026, the Company had a remaining performance obligation of $5.1 million; the Company expects to recognize the substantial majority of that amount as other fee revenues over the next 12 months. Contract Costs Contract costs relate to sales commissions paid on subscription contracts that are capitalized within our Machinio and Software Solutions businesses. Contract costs are amortized on a straight-line basis over the expected life of the customer contract. The contract cost balance was $2.4 million as of March 31, 2026, and $2.3 million as of September 30, 2025, and is included in the line-item Prepaid expenses and other current assets, and Other assets on the Condensed Consolidated Balance Sheets. Amortization expense was $0.4 million and $0.4 million during the three months ended March 31, 2026 and 2025, respectively, and $0.8 million and $0.8 million during the six months ended March 31, 2026, and 2025, respectively. Risk Associated with Certain Concentrations For the majority of buyers that receive goods before payment to the Company is made, credit evaluations are performed; however, for the remaining buyers, goods are not shipped before payment is made, and as a result the Company is not subject to significant collection risk from those buyers. However, for a limited number of financially qualified buyers, which can include re-sellers, we may from time-to-time extend credit for certain large purchases with negotiated payment periods. Credit terms commonly require payment to be made within 30 days, but where commercial terms or market conditions warrant these payment terms may be extended for up to six months. As a result, our consolidated accounts receivable balances are typically a small component of our overall financial position but may, at times, be concentrated among a limited, small number of such buyers. Collection risk from and credit exposure to these financially qualified buyers is regularly reviewed by management and adjusted as needed. For consignment sales transactions, funds are typically collected from buyers and are held by the Company on the sellers' behalf. The funds are included in Cash and cash equivalents on the Condensed Consolidated Balance Sheets. The Company releases the funds to the seller, less the Company's commission and other fees due, through Accounts payable after the buyer has accepted the goods or within 30 days, depending on the state where the buyer and seller conduct business. Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash in banks within non-interest bearing, interest-bearing, and earnings allowance checking accounts, as well as cash equivalent money market funds, all of which exceed the applicable U.S. federal (FDIC and/or SIPC), local jurisdiction (foreign banking institutions) insurance limits, and Accounts receivable. The Company deposits its cash in interest bearing checking accounts, acquires cash equivalent money market funds, and holds short-term investments designated as held-to-maturity investment securities, each with financial institutions that the Company considers to be of high credit quality. Management continually monitors the financial institutions with whom we conduct business and responds appropriately, when necessary, to manage potential risk exposure to our cash balances above the insurance limits. The Company has multiple vendor contracts with Amazon.com, Inc. under which it acquires and sells commercial merchandise. While purchase model transactions account for less than 20% of our total GMV, the cost of inventory for purchase model transactions is the most significant component of our consolidated Costs of goods sold. $15.9 million and $10.1 million of inventory purchased under such contracts with Amazon.com, Inc. is included in our Inventory balances on our Condensed Consolidated Balance Sheets as of March 31, 2026 and September 30, 2025, respectively. The Company's vendor contracts with respect to sourcing or consigning merchandise for our RSCG segment generally reflect the concentration dynamics inherent to the retail industry. Recent Accounting Pronouncements Accounting Standards Adopted In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. It will require organizations to provide enhanced disclosures primarily regarding significant segment expenses. The Company adopted the new standard effective with our Annual Report on Form 10-K for the fiscal year ended September 30, 2025. In accordance with the ASU, we have disclosed on a retrospective basis the significant expense, by segment, in deriving our segment profit (loss) measure; see Note 14 - Segment Information for further information. Accounting Standards Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU will require organizations to disclose specific categories in their tax rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. The guidance will be effective for the Company beginning with its Annual Report on Form 10-K for the fiscal year ending September 30, 2026. The guidance is required to be applied on a prospective basis; however, retrospective application is permitted. The Company expects to adopt this ASU on a retrospective basis and while the adoption is not expected to have an impact on the Company’s consolidated financial position, results of operations, or cash flows, it is expected to result in expanded income tax disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income (Topic 220): Disaggregation of Income Statement Expenses. This ASU will require organizations to disaggregate certain expense captions an entity presents on the face of the income statement into specific categories in disclosures within the footnotes to the financial statements. This guidance will be effective for the Company beginning with its Annual Report on Form 10-K for the fiscal year ending September 30, 2028. The guidance is required to be applied on a prospective basis; however, retrospective application is permitted. The Company is currently evaluating the effect that the adoption of this ASU may have on its consolidated financial statements. In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. This ASU modernizes the accounting for internal-use software, removing all references to software development stages and instead, requires capitalization of software costs when management has committed to the software project and it is probable the software will be completed and perform its intended use. This guidance will be effective for the Company beginning with its Annual Report on Form 10-K for the fiscal year ended September 30, 2029. Early adoption is permitted. The Company is currently evaluating the effect that the adoption of this ASU may have on its consolidated financial statements.