Operations	9 Months Ended
Operations	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operations	1. Description of Businesses Aspen Technology, Inc. ("Heritage AspenTech"), together with its subsidiaries (“New AspenTech" or “Company”), is a leading industrial software company that develops solutions to address complex industrial environments where it is critical to optimize the asset design, operations and maintenance lifecycle. Through the Company's unique combination of product capabilities and deep domain expertise and award-winning innovation, customers across diverse end markets in capital-intensive industries can improve its operational excellence while achieving sustainability goals. The Company operates globally in 75 countries as of June 30, 2022. Completion of Acquisition On October 10, 2021, Emerson Electric Co. (“Emerson”) entered into a definitive agreement (the “Transaction Agreement”) with Aspen Technology, Inc. (“Heritage AspenTech”) to contribute the Emerson Industrial Software Business (the "Industrial Software Business"), along with $6.014 billion in cash, to create New AspenTech (the “Transaction”). The Industrial Software Business operates Open Systems International, Inc. (“OSI Inc.”) and Geological Simulation Software (“GSS”). The Transactions closed on May 16, 2022 (“Closing Date”). Emerson owns 55% of New AspenTech on a fully diluted basis as of June 30, 2022. Basis of Presentation The Transaction has been accounted for as a business combination in accordance with U.S. GAAP, with the Industrial Software Business treated as the “acquirer” and Heritage AspenTech treated as the “acquired” company for financial reporting purposes. Accordingly, the historical financial statements of the Industrial Software Business are the historical financial statements of New AspenTech following the completion of the Transaction. In addition, the assets, liabilities and results of operations of Heritage AspenTech (including the impact of purchase accounting, which resulted in increased amortization expense for acquired intangible assets, among other impacts) is only included in New AspenTech’s financial statements from the Closing Date. New AspenTech’s assets, liabilities and results of operations have not been restated retroactively to reflect the historical financial position or results of operations of Heritage AspenTech. For the year ended June 30, 2022, the consolidated and combined financial statements comprise the results of the Industrial Software Business for the nine-month period, and the results of Heritage AspenTech since May 16, 2022, the date of the Merger. Certain financial information for the periods ended September 30, 2021 and 2020 have been reclassed to conform to the consolidated and combined financial statements for the nine-month period ended June 30, 2022. The Industrial Software Business is a combination of the GSS (subsequently renamed Subsurface Science & Engineering Solutions, or "SSE", after the Closing Date) and the OSI Inc. businesses. Its results of operations and financial statements have previously been reflected in Emerson’s consolidated financial statements. The financial statements of the Industrial Software Business prior to the Closing Date present the historical financial position, results of operations, and cash flows as historically managed within Emerson and include all accounts of the Industrial Software Business in a combination of dedicated legal entities and shared legal entities of Emerson. The financial statements of the Industrial Software Business prior to the Closing Date also reflect an allocation of a portion of Emerson’s general corporate costs. While management believes the methodologies and assumptions used to allocate these costs are reasonable, the financial statements prior to the Closing Date do not purport to represent the financial position, the results of operations, changes in equity, and cash flows of the Industrial Software Business had it operated as a stand-alone entity. Change in Fiscal year On the Closing Date, New AspenTech changed its fiscal year end from September 30 to June 30. As a result, the Company’s results of operations, cash flows, and all transactions impacting stockholders' equity presented in this Transition Report on Form 10-KT are for the nine-month period ended June 30, 2022 whereas its fiscal years 2021 and 2020 are for the twelve months ended September 30, 2021 and 2020 unless otherwise noted. As such, the Company’s fiscal year 2022, or fiscal 2022, refers to the period from October 1, 2021 to June 30, 2022. This Transition Report on Form 10-KT also includes an unaudited consolidated and combined statements of operations and cash flows for the comparable stub period of October 1, 2020 to June 30, 2021; see Note 21, “Transition Period Comparative Data (unaudited)” for further information. Russia and Ukraine While the Company has no operations in Ukraine, the ongoing conflict there could negatively impact its financial position and results of operations. The United States and other governments have imposed sanctions and taken other regulatory actions that adversely affect doing business in Russia and with Russian companies. The Company licenses software and provides related services to customers in Russia and has operations there. The Company had net sales of approximately $9.9 million for the nine-month period ended June 30, 2022, and total assets of approximately $23.4 million as of June 30, 2022, related to operations in Russia. The Company continues to evaluate the impact of the various sanctions and export control measures imposed by the United States and other governments on its ability to do business in Russia, maintain contracts with vendors and pay employees in Russia, as well as receive payment from customers in Russia or Ukraine. The outcome of these assessments will depend on how the conflict evolves and on further actions that may be taken by the United States, Russia, and other governments around the world. No material impact to supply chain operations is expected due to the conflict in Ukraine.