Commitments And Contingencies	12 Months Ended
Commitments And Contingencies	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies Litigation Lynwood Investment CY Limited v. F5 Networks et al. On June 8, 2020, Lynwood Investment CY Limited (“Lynwood”) filed a lawsuit in the United States District Court for the Northern District of California against the Company and certain affiliates, along with other defendants. In its complaint, Lynwood claims to be the assignee of all rights and interests of Rambler Internet Holding LLC (“Rambler”), and alleges that the intellectual property in the NGINX software originally released by the co-founder of NGINX in 2004 belongs to Rambler (and therefore Lynwood, by assignment) because the software was created and developed while the co-founder was employed by Rambler. Lynwood asserts 26 causes of action against the various defendants, including copyright infringement, violation of trademark law, tortious interference, conspiracy, and fraud. The complaint seeks damages, disgorgement of profits, fees and costs, declarations of copyright and trademark ownership, trademark cancellations, and injunctive relief. Lynwood also initiated several trademark opposition and cancellation proceedings before the Trademark Trial and Appeal Board of the United States Patent and Trademark Office, which have all since been suspended. In August and October 2020, the Company and the other defendants filed motions to dismiss all claims asserted against them in the lawsuit. While these motions were pending, the Court ordered Lynwood to select ten of its twenty-six claims to litigate through trial while the remaining sixteen claims would be stayed pending resolution of the ten selected claims. On March 25 and 30, 2021, the Court dismissed the ten selected claims and granted Lynwood leave to cure the deficiencies in its complaint though it expressed doubt about Lynwood’s ability to do so. The Court further ruled that Lynwood may not add new causes of action or add new parties without stipulation or leave of court, and that unless Lynwood corrects “all the defects” identified in the Court’s orders and the Company’s and other defendants’ motions to dismiss, the Court will dismiss the ten claims with prejudice. On April 6, 2021, the Court referred the parties to private mediation to be completed by June 1, 2021. Pursuant to the Court’s order, the parties held a private mediation on May 27, 2021. The matter did not resolve. On April 29, 2021, Lynwood filed its amended complaint, seeking the same relief against the Company and other defendants. On May 27, 2021, the Company and other defendants filed a consolidated motion to dismiss the claims Lynwood had selected to proceed to litigate through trial, reserving their right to move to dismiss the 16 stayed claims once the Court lifts the stay. The motion to dismiss was set to be heard by the Court on October 14, 2021, but on October 11, 2021, the Court vacated the hearing and gave notice that it will decide the motion on the papers without oral argument. On August 16, 2022, the Court granted the consolidated motion to dismiss the claims Lynwood had selected to proceed to litigate through trial, without leave to amend the claims, thereby dismissing those claims with prejudice. On September 9, 2022, the parties stipulated to the dismissal of the remaining 16 stayed claims, with prejudice, and the Court entered a final judgment. On September 14, 2022, Lynwood filed a notice of appeal to the Ninth Circuit Court of appeals to appeal the Court’s dismissal of the claims Lynwood had selected to proceed to litigate through trial. Lynwood’s opening brief is currently due December 16, 2022 and the Company’s answer brief will be due January 17, 2023. Lynwood’s reply will be due February 7, 2023. In addition to the above matters, the Company is subject to a variety of legal proceedings, claims, investigations, and litigation arising in the ordinary course of business, including intellectual property litigation. Management believes that the Company has meritorious defenses to the allegations made in its pending cases and intends to vigorously defend these lawsuits; however, the Company is unable to currently determine if an unfavorable outcome is probable or estimate any potential amount or range of possible loss of these or similar matters. There are many uncertainties associated with any litigation and these actions or other third-party claims against the Company may cause it to incur costly litigation and/or substantial settlement charges that could have a material adverse effect on the Company's business, financial condition, results of operations, and cash flows. The Company records an accrual for loss contingencies for legal proceedings when it believes that an unfavorable outcome is both (a) probable and (b) the amount or range of any possible loss is reasonably estimable. The Company has not recorded any accrual for loss contingencies associated with such legal proceedings or the investigations discussed above.