F5 (FFIV) 10-K 14 Nov 23 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Sep. 30, 2023	Nov. 07, 2023	Mar. 31, 2023
Cover [Abstract]
Entity Central Index Key	0001048695
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	000-26041
Entity Registrant Name	F5, Inc.
Entity Incorporation, State or Country Code	WA
Entity Tax Identification Number	91-1714307
Entity Address, Address Line One	801 5th Avenue
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98104
City Area Code	206
Local Phone Number	272-5555
Title of 12(b) Security	Common stock, no par value
Trading Symbol	FFIV
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 8,760,048,466
Entity Common Stock, Shares Outstanding		59,707,211
Documents Incorporated by Reference [Text Block]	Information required in response to Part III of this Form 10-K (Items 10, 11, 12, 13 and 14) is hereby incorporated by reference to the specified portions of the Registrant’s Definitive Proxy Statement for the Annual Shareholders Meeting for fiscal year 2023, which Definitive Proxy Statement shall be filed with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days of the end of the fiscal year to which this Report relates
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--09-30
Amendment Flag	false

Auditor Information

Auditor Information	12 Months Ended
	Sep. 30, 2023
Cover [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Seattle, Washington
Auditor Firm ID	238

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
ASSETS
Cash and cash equivalents	$ 797,163	$ 758,012
Short-term investments	6,160	126,554
Accounts receivable, net of allowances of $3,561 and $6,020	454,832	469,979
Inventories	35,874	68,365
Other current assets	554,744	489,314
Total current assets	1,848,773	1,912,224
Property and equipment, net	170,422	168,182
Operating lease right-of-use assets	195,471	227,475
Long-term investments	5,068	9,544
Deferred tax assets	295,308	183,365
Goodwill	2,288,678	2,259,282
Other assets, net	444,613	516,122
Total assets	5,248,333	5,276,194
LIABILITIES AND SHAREHOLDERS’ EQUITY
Accounts payable	63,315	113,178
Accrued liabilities	282,890	309,819
Deferred revenue	1,126,576	1,067,182
Current portion of long-term debt	0	349,772
Total current liabilities	1,472,781	1,839,951
Deferred tax liabilities	4,637	2,781
Deferred revenue, long-term	648,545	624,398
Operating lease liabilities, long-term	239,565	272,376
Other long-term liabilities	82,573	67,710
Total long-term liabilities	975,320	967,265
Commitments and contingencies (Note 12)
Shareholders’ equity
Preferred stock, no par value; 10,000 shares authorized, no shares outstanding	0	0
Common stock, no par value; 200,000 shares authorized, 59,207 and 59,860 shares issued and outstanding	24,399	91,048
Accumulated other comprehensive loss	(23,221)	(26,176)
Retained earnings	2,799,054	2,404,106
Total shareholders’ equity	2,800,232	2,468,978
Total liabilities and shareholders’ equity	$ 5,248,333	$ 5,276,194

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 3,561	$ 6,020
Preferred stock, par value (USD per share)	$ 0	$ 0
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (USD per share)	$ 0	$ 0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	59,207,000	59,860,000
Common stock, shares outstanding	59,207,000	59,860,000

Consolidated Income Statements

Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Net revenues
Net revenues	$ 2,813,169	$ 2,695,845	$ 2,603,416
Cost of net revenues
Cost of net revenues	593,308	539,627	493,146
Gross profit	2,219,861	2,156,218	2,110,270
Operating expenses
Sales and marketing	878,215	926,591	929,983
Research and development	540,285	543,368	512,627
General and administrative	263,405	274,558	273,635
Restructuring charges	65,388	7,909	0
Total	1,747,293	1,752,426	1,716,245
Income from operations	472,568	403,792	394,025
Other income (expense), net	13,420	(18,399)	(7,088)
Income before income taxes	485,988	385,393	386,937
Provision for income taxes	91,040	63,233	55,696
Net income	$ 394,948	$ 322,160	$ 331,241
Net income per share - basic (USD per share)	$ 6.59	$ 5.34	$ 5.46
Weighted average shares - basic (shares)	59,909	60,274	60,707
Net income per share - diluted (USD per share)	$ 6.55	$ 5.27	$ 5.34
Weighted average shares - diluted (shares)	60,270	61,097	62,057
Product [Member]
Net revenues
Net revenues	$ 1,334,638	$ 1,317,117	$ 1,247,084
Cost of net revenues
Cost of net revenues	375,192	319,713	286,293
Service [Member]
Net revenues
Net revenues	1,478,531	1,378,728	1,356,332
Cost of net revenues
Cost of net revenues	$ 218,116	$ 219,914	$ 206,853

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 394,948	$ 322,160	$ 331,241
Other comprehensive income (loss):
Foreign currency translation adjustment	1,477	(4,502)	(68)
Available-for-sale securities:
Unrealized gains (losses) on available-for-sale securities, net of taxes of $286, $(160), and $(234) for the years ended September 30, 2023, 2022, and 2021, respectively	2,090	(1,449)	(1,557)
Reclassification adjustment for realized (losses) gains included in net income, net of taxes of $78, $48, and $(69) for the years ended September 30, 2023, 2022, and 2021, respectively	(612)	(152)	268
Net change in unrealized gains (losses) on available-for-sale securities, net of tax	1,478	(1,601)	(1,289)
Total other comprehensive income (loss)	2,955	(6,103)	(1,357)
Comprehensive income	$ 397,903	$ 316,057	$ 329,884

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 286	$ (160)	$ (234)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	$ 78	$ 48	$ (69)

Consolidated Statement Of Share

Consolidated Statement Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Accumulated Other Comprehensive Loss	Retained Earnings
Balance, shares at Sep. 30, 2020		61,099,000
Balance at Sep. 30, 2020	$ 2,232,268	$ 305,453	$ (18,716)	$ 1,945,531
Exercise of employee stock options, shares		164,000
Exercise of employee stock options	4,864	$ 4,864
Issuance of stock under employee stock purchase plan, shares		542,000
Issuance of stock under employee stock purchase plan	60,888	$ 60,888
Issuance of restricted stock, shares		1,430,000
Repurchase of common stock, shares		(2,501,000)
Repurchase of common stock	(500,000)	$ (411,056)		(88,944)
Taxes paid related to net share settlement of equity awards, shares		(82,000)
Taxes paid related to net share settlement of equity awards	(14,032)	$ (14,032)
Stock-based compensation	246,341	$ 246,341
Net income	331,241			331,241
Other comprehensive income (loss)	(1,357)		(1,357)
Balance, shares at Sep. 30, 2021		60,652,000
Balance at Sep. 30, 2021	2,360,213	$ 192,458	(20,073)	2,187,828
Exercise of employee stock options, shares		143,000
Exercise of employee stock options	3,613	$ 3,613
Issuance of stock under employee stock purchase plan, shares		412,000
Issuance of stock under employee stock purchase plan	60,927	$ 60,927
Issuance of restricted stock, shares		1,368,000
Repurchase of common stock, shares		(2,611,000)
Repurchase of common stock	(500,023)	$ (394,141)		(105,882)
Taxes paid related to net share settlement of equity awards, shares		(104,000)
Taxes paid related to net share settlement of equity awards	(21,025)	$ (21,025)
Stock-based compensation	249,216	$ 249,216
Net income	322,160			322,160
Other comprehensive income (loss)	$ (6,103)		(6,103)
Balance, shares at Sep. 30, 2022	59,860,000	59,860,000
Balance at Sep. 30, 2022	$ 2,468,978	$ 91,048	(26,176)	2,404,106
Exercise of employee stock options, shares	56,516	56,000
Exercise of employee stock options	$ 1,491	$ 1,491
Issuance of stock under employee stock purchase plan, shares		501,000
Issuance of stock under employee stock purchase plan	58,468	$ 58,468
Issuance of restricted stock, shares		1,335,000
Repurchase of common stock, shares		(2,454,000)
Repurchase of common stock	(350,049)	$ (350,049)
Taxes paid related to net share settlement of equity awards, shares		(91,000)
Taxes paid related to net share settlement of equity awards	(13,209)	$ (13,209)
Stock-based compensation	236,650	$ 236,650
Net income	394,948			394,948
Other comprehensive income (loss)	$ 2,955		2,955
Balance, shares at Sep. 30, 2023	59,207,000	59,207,000
Balance at Sep. 30, 2023	$ 2,800,232	$ 24,399	$ (23,221)	$ 2,799,054

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net income	$ 394,948	$ 322,160	$ 331,241
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	236,650	249,216	243,279
Depreciation and amortization	112,702	115,609	115,424
Non-cash operating lease costs	38,528	38,735	38,375
Deferred income taxes	(108,521)	(40,244)	(76,930)
Impairment of assets	3,455	6,175	40,698
Other	1,372	1,267	737
Changes in operating assets and liabilities (excluding effects of the acquisition of businesses):
Accounts receivable	16,704	(130,605)	(46,289)
Inventories	32,491	(46,310)	5,843
Other current assets	(64,959)	(144,628)	(84,328)
Other assets	16,591	(87,008)	(110,653)
Accounts payable and accrued liabilities	(63,100)	19,163	22,933
Deferred revenue	81,741	191,147	216,431
Lease liabilities	(45,193)	(52,046)	(51,565)
Net cash provided by operating activities	653,409	442,631	645,196
Investing activities
Purchases of investments	(1,789)	(61,284)	(472,165)
Maturities of investments	111,330	260,357	197,279
Sales of investments	16,085	120,578	271,521
Acquisition of businesses, net of cash acquired	(35,049)	(67,911)	(411,319)
Purchases of property and equipment	(54,184)	(33,624)	(30,651)
Net cash provided by (used in) investing activities	36,393	218,116	(445,335)
Financing activities
Proceeds from the exercise of stock options and purchases of stock under employee stock purchase plan	59,959	64,540	65,752
Repurchase of common stock	(350,049)	(500,023)	(500,000)
Payments on term debt agreement	(350,000)	(20,000)	(20,000)
Taxes paid related to net share settlement of equity awards	(13,209)	(21,025)	(14,032)
Net cash used in financing activities	(653,299)	(476,508)	(468,280)
Net increase (decrease) in cash, cash equivalents and restricted cash	36,503	184,239	(268,419)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	2,125	(6,365)	(74)
Cash, cash equivalents and restricted cash, beginning of year	762,207	584,333	852,826
Cash, cash equivalents and restricted cash, end of year	800,835	762,207	584,333
Supplemental disclosures of cash flow information
Cash paid for taxes, net of refunds	191,569	110,036	99,378
Cash paid for amounts included in the measurement of operating lease liabilities	52,893	58,592	61,504
Cash paid for interest on long-term debt	2,970	7,981	5,280
Supplemental disclosures of non-cash activities
Right-of-use assets obtained in exchange for lease obligations	$ 10,544	$ 20,778	$ 13,051

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	Summary of Significant Accounting Policies The Company F5, Inc. (the "Company") is a leading provider of multi-cloud application security and delivery solutions which enable its customers to develop, deploy, operate, secure, and govern applications in any architecture, from on-premises to the public cloud. The Company's cloud, software, and hardware solutions enable its customers to deliver digital experiences to their customers faster, reliably, and at scale. The Company's enterprise-grade application services are available as cloud-based, software-as-a-service, and software-only solutions optimized for multi-cloud environments, with modules that can run independently, or as part of an integrated solution on its high-performance appliances. In connection with its solutions, the Company offers a broad range of professional services, including consulting, training, maintenance, and other technical support services. Accounting Principles The Company’s consolidated financial statements and accompanying notes are prepared on the accrual basis of accounting in accordance with generally accepted accounting principles in the United States of America ("GAAP"). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates and Assumptions The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Examples of estimates and assumptions include: revenue recognition, identifying and evaluating the performance obligations of contracts with non-standard terms, and the allocation of purchase consideration based on the relative fair value standalone sales price of these performance obligations; business combinations, including the determination of fair value for acquired developed technology assets and the evaluation and selection of significant assumptions such as revenue growth rate and technology migration curve; and the incremental borrowing rate for measuring lease obligations. Actual results may differ materially from management's estimates and assumptions. Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The Company invests its cash and cash equivalents in deposits with four major financial institutions, which, at times, exceed federally insured limits. The Company has not experienced any losses on its cash and cash equivalents. Amounts included in restricted cash represent those for which the Company's use is restricted by a contractual agreement. Investments The Company classifies its debt investments as available-for-sale. Debt investments, consisting of money market funds, corporate and municipal bonds and notes, the United States government and agency securities are reported at fair value with the related unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in shareholders’ equity. Realized gains and losses, credit allowances and impairments due to credit losses are included in other income (expense) in the Company’s consolidated income statements. Debt investments with maturities of less than one year or where management’s intent is to use the investments to fund current operations are classified as short-term investments. Debt investments with maturities of greater than one year are classified as long-term investments. As an approximation to fair value, equity investments are measured using net asset value (“NAV”) and are classified as long-term investments. Unrealized and realized gains and losses are recorded in other income (expense) in the Company's consolidated income statements. Accounts Receivable Trade accounts receivable are recorded at the invoiced amount, net of allowances for credit losses for any potential uncollectible amounts. The allowance for credit losses is based on the assessment of the collectability of accounts. Management regularly reviews the adequacy of the allowance for credit losses on a collective basis by considering the age of each outstanding invoice, each customer’s expected ability to pay and collection history, current market conditions, and reasonable and supportable forecasts of future economic conditions to determine whether the allowance is appropriate. Accounts receivable deemed uncollectible are charged against the allowance for credit losses when identified. For fiscal years ended September 30, 2023 and 2022, the allowance for credit losses was not material. Unbilled Receivables Unbilled receivables represent amounts related to the Company's unconditional right to consideration associated with contracts with customers that have not yet been billed. Unbilled receivables are converted to accounts receivable at the point in time when the Company has the contractual right to invoice its customers. As of September 30, 2023, unbilled receivables that are expected to be reclassified to accounts receivable within the next 12 months are included in other current assets, with those expected to be transferred to accounts receivables in more than 12 months included in other assets. Concentration of Credit Risk The Company extends credit to customers and is therefore subject to credit risk. The Company performs initial and ongoing credit evaluations of its customers’ financial condition and does not require collateral. An allowance for credit losses is recorded for any potential uncollectible amount. Estimates are used in determining the allowance for credit losses in accordance with the Accounts Receivable policy. See Note 15 - Segment Information, for disaggregated accounts receivable by significant customer. The Company maintains its cash and investment balances with high credit quality financial institutions. Fair Value of Financial Instruments Short-term and long-term investments are recorded at fair value as the underlying securities are classified as available-for-sale with any unrealized gains or losses being recorded to other comprehensive income (or loss). The fair value for securities held is determined using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. Inventories The Company outsources the manufacturing of its pre-configured hardware platforms to contract manufacturers, who assemble each product to the Company’s specifications. As protection against component shortages and to provide replacement parts for its service teams, the Company also stocks limited supplies of certain key product components. The Company reduces inventory to net realizable value based on excess and obsolete inventories determined primarily by historical usage and forecasted demand. Inventories consist of hardware and related component parts and are recorded at the lower of cost and net realizable value (as determined by the first-in, first-out method). Property and Equipment Property and equipment are stated at net book value. Depreciation of property and equipment is provided using the straight-line method over the estimated useful lives of the assets, ranging from two Business Combinations The Company’s business combinations are accounted for under the acquisition method. Management allocates the fair value of purchase consideration to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition date. The excess of the fair value of purchase consideration over the fair values of these identifiable assets and liabilities is recorded as goodwill. Such valuations require management to make significant estimates and assumptions, especially with respect to intangible assets. Goodwill Goodwill represents the excess purchase price over the estimated fair value of net assets acquired as of the acquisition date. The Company tests goodwill for impairment on an annual basis and between annual tests when impairment indicators are identified, and goodwill is written down when impaired. For its annual goodwill impairment test in all periods to date, the Company has operated under one reporting unit and the fair value of its reporting unit has been determined by the Company’s enterprise value. The Company performs its annual goodwill impairment test during the second fiscal quarter. For its annual impairment test performed in the second quarter of fiscal 2023, the Company completed a quantitative assessment and determined that there was no impairment of goodwill. The Company also considered potential impairment indicators of goodwill at September 30, 2023 and noted no indicators of impairment. Intangible Assets Intangible assets with finite lives consist of acquired developed technology, customer relationships, patents and trademarks, trade names, and non-compete covenants acquired through business combinations or asset acquisitions. Intangible assets acquired through business combinations are recorded at their respective estimated fair values upon acquisition close. Other intangible assets acquired through asset acquisitions are recorded at their respective cost. The Company determines the estimated useful lives for acquired intangible assets based on the expected future cash flows associated with the respective asset. The Company's intangible assets with finite lives are amortized using the straight-line method over their estimated useful lives, ranging from four Software Development Costs The authoritative guidance requires certain internal software development costs related to software to be sold to be capitalized upon the establishment of technological feasibility. Capitalized software development costs are amortized over the remaining estimated economic life of the product. The Company's software development costs incurred subsequent to achieving technological feasibility have not been significant and, as a result, all software development costs have been expensed as research and development activities as incurred. Internal-Use Software The Company capitalizes costs incurred during the application development stage associated with the development of internal-use software systems. The capitalized costs are then amortized over the estimated useful life of the software, which is generally three Impairment of Long-Lived Assets The Company assesses the impairment of long-lived assets whenever events or changes in business circumstances indicate that the carrying amount of an asset may not be recoverable. When such events occur, management determines whether there has been impairment by comparing the anticipated undiscounted net future cash flows to the related asset’s carrying value. If impairment exists, the asset is written down to its estimated fair value. Revenue Recognition The Company sells products through distributors, resellers, and directly to end users. Revenue related to the Company's contracts with customers is recognized by following a five-step process: • Identify the contract(s) with a customer. Evidence of a contract generally consists of a purchase order issued pursuant to the terms and conditions of a distributor, reseller or end user agreement. • Identify the performance obligations in the contract. Performance obligations are identified in the Company's contracts and include hardware, hardware-based software, software-only solutions, cloud-based subscription services as well as a broad range of service performance obligations including consulting, training, installation and maintenance. • Determine the transaction price. The purchase price stated in an agreed upon purchase order is generally representative of the transaction price. The Company offers several programs in which customers are eligible for certain levels of rebates if certain conditions are met. When determining the transaction price, the Company considers the effects of any variable consideration. • Allocate the transaction price to the performance obligations in the contract. The transaction price in a contract is allocated based upon the relative standalone selling price of each distinct performance obligation identified in the contract. • Recognize revenue when (or as) the entity satisfies a performance obligation. The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring control of promised products and services to a customer. Revenue is recognized net of any taxes collected, which are subsequently remitted to governmental authorities. Shipping and handling fees charged to the Company’s customers are recognized as product revenue in the period shipped and the related costs for providing these services are recorded as a cost of sale. The following is a description of the principal activities from which the Company generates revenue: Product Revenue from the sale of the Company's hardware and perpetual software products is generally recognized at a point in time when the product has been fulfilled and the customer is obligated to pay for the product. The Company also offers several products by subscription, either through term-based license agreements or as SaaS offerings. Revenue for term-based license agreements is recognized at a point in time, when the Company delivers the software license to the customer and the subscription term has commenced. For the Company's SaaS offerings, revenue is recognized ratably as the services are provided. Hardware, including the software run on those devices is considered systems revenue. Perpetual or subscription software offerings that are, or have the ability to be deployed on a standalone basis, along with the Company's SaaS offerings are considered software revenue. When rights of return are present and the Company cannot estimate returns, revenue is recognized when such rights of return lapse. Payment terms to customers are generally net 30 days to net 60 days. Global Services Revenues for post-contract customer support ("PCS") are recognized on a straight-line basis over the service contract term. PCS includes a limited period of telephone support, updates, repair or replacement of any failed product or component that fails during the term of the agreement, bug fixes and rights to upgrades, when and if available. Consulting services are customarily billed at fixed hourly rates, plus out-of-pocket expenses, and revenues are recognized as the consulting is delivered. Similarly, training revenue is recognized as the training is completed. Contract Acquisition Costs Sales commissions earned by the Company's sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for initial service contracts and subscription offerings are deferred and then amortized as an expense on a straight-line basis over the period of benefit, which management has determined to be 4.5 years for initial service and 3 to 5 years for subscription offerings. Flexible Consumption Program The Company enters into certain contracts with customers, including flexible consumption programs and multi-year subscriptions, with non-standard terms and conditions. Management assesses contractual terms in these agreements to identify and evaluate performance obligations. Management allocates consideration to each performance obligation based on relative fair value using standalone selling price and recognizes associated revenue as control is transferred to the customer. Guarantees and Product Warranties In the normal course of business to facilitate sales of its products, the Company indemnifies other parties, including customers, resellers, lessors, and parties to other transactions with the Company, with respect to certain matters. The Company has agreed to hold the other party harmless against losses arising from a breach of representations or covenants, or out of intellectual property infringement or other claims made against certain parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. The Company has entered into indemnification agreements with its officers and directors, and the Company’s bylaws contain similar indemnification obligations to the Company’s agents. It is not possible to determine the maximum potential amount under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. The Company offers warranties of one year for hardware for those customers without service contracts, with the option of purchasing additional warranty coverage in yearly increments. The Company accrues for warranty costs as part of its cost of sales based on associated material product costs and technical support labor costs. Warranty expense and accrued warranty costs were not material for all periods presented. Research and Development Research and development expenses consist of salaries and related benefits of product development personnel, prototype materials and expenses related to the development of new and improved products, and an allocation of facilities, depreciation and amortization expense. Research and development expenses are reflected in the income statements as incurred. Advertising Advertising costs are expensed as incurred. The Company incurred $8.9 million, $15.4 million and $10.0 million in advertising costs during the fiscal years 2023, 2022 and 2021, respectively. Income Taxes Deferred income tax assets and liabilities are determined based upon differences between the financial statement and income tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The realization of deferred tax assets is based on historical tax positions and estimates of future taxable income. A valuation allowance is recorded when it is more-likely-than-not that some of the deferred tax assets will not be realized. The Company assesses whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the financial statements. The Company may recognize the tax benefit from an uncertain tax position only if it is more-likely-than-not that the tax position will be sustained on examination by the taxing authorities, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The tax benefits to be recognized in the financial statements from such a position is measured as the largest amount of benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. The Company adjusts these liabilities based on a variety of factors, including the evaluation of information not previously available. These adjustments are reflected as increases or decreases to income tax expense in the period in which new information is available. Foreign Currency The functional currency for the Company’s foreign subsidiaries is either the U.S. dollar or the local currency depending on the assessment of management. An entity’s functional currency is determined by the currency of the economic environment in which the majority of cash is generated and expended by the entity. The financial statements of all majority-owned subsidiaries and related entities, with a functional currency other than the U.S. dollar, have been translated into U.S. dollars. All assets and liabilities of the respective entities are translated at year-end exchange rates and all revenues and expenses are translated at average rates during the respective period. Translation adjustments are reported as other comprehensive income (loss) in the consolidated statements of comprehensive income. Foreign currency transaction gains and losses are a result of the effect of exchange rate changes on transactions denominated in currencies other than the functional currency, including U.S. dollars. Gains and losses on those foreign currency transactions are included in determining net income or loss for the period of exchange and are recorded in other income, net. The net effect of foreign currency gains and losses was not material during the fiscal years ended September 30, 2023, 2022 and 2021. Segments Operating segments are defined as components of an enterprise for which separate financial information is available and evaluated regularly by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources and in assessing performance. Management has determined that the Company is organized as, and operates in, one reportable operating segment. Stock-based Compensation The Company issues incentive awards to its employees through stock-based compensation consisting of restricted stock units ("RSUs"). RSUs are payable in shares of the Company’s common stock as the periodic vesting requirements are satisfied, generally over one The Company offers an Employee Stock Purchase Plan ("ESPP") that permits eligible employees to purchase shares of the Company’s common stock at a discount. In determining the fair value of shares issued under the ESPP, the Company uses the Black-Scholes option pricing model. The assumptions within the option pricing model are based on management’s best estimates at that time, which impact the fair value of the ESPP option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the life of the ESPP option. The Company has also issued stock options as replacement awards, most notably for those assumed as part of business combinations. The Company used the Black-Scholes option pricing model to determine the fair value of the stock option replacement awards. The assumptions within the option pricing model are based on management’s best estimates at that time, which impact the fair value of the option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the term of the option. The Company accounts for stock-based compensation using the straight-line attribution method for recognizing compensation expense. The Company recognizes compensation expense for only the portion of stock-based awards that are expected to vest. Therefore, the Company applies estimated forfeiture rates that are derived from historical employee termination behavior. Based on historical differences with forfeitures of stock-based awards granted to the Company’s executive officers and Board of Directors versus grants awarded to all other employees, the Company has developed separate forfeiture expectations for these two groups. The Company issues incentive awards to certain current executive officers as part of its annual equity awards program. A portion of the aggregate number of RSUs issued to executive officers vest in equal quarterly increments, and a portion is subject to the Company achieving specified performance goals. In fiscal 2018, the Company's Talent and Compensation Committee adopted a set of metrics for the performance stock awards, including (1) 50% of the annual performance stock grant is based on achieving certain annual revenue; (2) 25% of the annual performance stock grant is based on achieving an increase annual software revenue compared to the prior year; and (3) 25% of the annual performance stock grant is based on relative total shareholder return ("TSR") benchmarked to the S&P 500 index. In fiscal 2023, the Company's Talent and Compensation Committee amended the metrics for the performance stock awards to replace software revenue with earnings per share. In each case, no vesting or payment with respect to a performance goal shall occur unless a minimum threshold is met for the applicable goal. Vesting and payment with respect to the performance goal is linear above the threshold of the applicable goal and is capped at achievement of 200% above target. The Company recognizes compensation costs for awards with performance conditions and market conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award and, for awards with performance conditions, when it concludes it is probable that the performance condition will be achieved. The Company reassesses the probability of vesting at each balance sheet date and adjusts compensation costs based on the probability assessment. Comprehensive Income Comprehensive income includes certain changes in equity that are excluded from net income. Specifically, unrealized gains or losses on securities and foreign currency translation adjustments. These changes are included in accumulated other comprehensive income or loss. Recently Adopted Accounting Standards There have been no material changes in recently issued or adopted accounting standards from those disclosed in the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2022.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Sep. 30, 2023
Revenue from Contracts with Customers [Abstract]
Revenue from Contract with Customers	Revenue from Contracts with Customers Capitalized Contract Acquisition Costs The table below shows significant movements in capitalized contract acquisition costs (current and noncurrent) for the years ended September 30, 2023, 2022, and 2021 (in thousands): 2023 2022 2021 Balance, beginning of year $ 77,220 $ 77,836 $ 70,396 Additional capitalized contract acquisition costs 26,960 37,897 41,719 Amortization of capitalized contract acquisition costs (37,712) (38,513) (34,279) Balance, end of year $ 66,468 $ 77,220 $ 77,836 Amortization of capitalized contract acquisition costs was $37.7 million, $38.5 million, and $34.3 million for the years ended September 30, 2023, 2022, and 2021, respectively, and is recorded in Sales and Marketing expense in the accompanying consolidated income statements. There was no impairment of any capitalized contract acquisition costs during any period presented. Contract Balances Timing may differ between the satisfaction of performance obligations and the invoicing and collection of amounts related to the Company's contracts with customers. Liabilities are recorded for amounts that are collected in advance of the satisfaction of performance obligations, or for contracts with customers that contain the Company's unconditional rights to consideration, for which the customer has not been billed. These liabilities are classified as current and non-current deferred revenue. The table below shows significant movements in the deferred revenue balances (current and noncurrent) for the years ended September 30, 2023, 2022, and 2021 (in thousands): 2023 2022 2021 Balance, beginning of year $ 1,691,580 $ 1,489,842 $ 1,272,632 Amounts added but not recognized as revenues 1,162,698 1,167,143 1,122,081 Deferred revenue acquired through acquisition of businesses 1,800 10,591 779 Revenues recognized related to the opening balance of deferred revenue (1,080,957) (975,996) (905,650) Balance, end of year $ 1,775,121 $ 1,691,580 $ 1,489,842 Remaining Performance Obligations Remaining performance obligations represent the amount of the transaction price under contracts with customers that are attributable to performance obligations that are unsatisfied or partially satisfied at the reporting date. The composition of unsatisfied performance obligations consists mainly of deferred service revenue, and to a lesser extent, deferred product revenue, for which the Company has an obligation to perform, and has not yet recognized as revenue in the consolidated financial statements. As of September 30, 2023, the total non-cancelable remaining performance obligations under the Company's contracts with customers was $1.8 billion and the Company expects to recognize revenues on approximately 63.5% of these remaining performance obligations over the next 12 months, 23.5% in year two, and the remaining balance thereafter. See Note 15 - Segment Information, for disaggregated revenue by significant customer and geographic region, as well as disaggregated product revenue by systems and software.

Business Combinations

Business Combinations	12 Months Ended
	Sep. 30, 2023
Business Combinations [Abstract]
Business Combinations	Business Combinations Fiscal Year 2023 Acquisition of Lilac Cloud, Inc. On January 22, 2023, the Company entered into a Merger Agreement (the “Lilac Merger Agreement”) with Lilac Cloud, Inc. ("Lilac"), a provider of innovative application delivery services. The transaction closed on February 1, 2023 with Lilac becoming a wholly-owned subsidiary of F5. The addition of Lilac’s Content Delivery Network ("CDN") technologies enhances F5’s portfolio of solutions that secure and optimize any application and Application Programming Interface ("API") anywhere. The acquired assets and assumed liabilities of Lilac were not material and the acquisition did not have a material impact to the Company's operating results.  Fiscal Year 2022 Acquisition of Threat Stack, Inc. In September 2021, the Company entered into a Merger Agreement (the “Threat Stack Merger Agreement”) with Threat Stack, Inc. ("Threat Stack"), a provider of cloud security and workload protection solutions. The transaction closed on October 1, 2021 with Threat Stack becoming a wholly-owned subsidiary of F5. The addition of Threat Stack’s cloud security capabilities to F5’s application and API protection solutions enhances visibility across application infrastructure and workloads to deliver more actionable security insights for customers. Pursuant to the Threat Stack Merger Agreement, at the effective time of the Merger, the capital stock of Threat Stack and the vested outstanding and unexercised stock options in Threat Stack were cancelled and converted to the right to receive $68.9 million in cash, subject to certain adjustments and conditions set forth in the Threat Stack Merger Agreement. Transaction costs associated with the acquisition were not material. As a result of the acquisition, the Company acquired all the assets and assumed all the liabilities of Threat Stack. The goodwill related to the Threat Stack acquisition is comprised primarily of expected synergies from combining operations and the acquired intangible assets that do not qualify for separate recognition. Goodwill related to the Threat Stack acquisition was not deductible for tax purposes. The results of operations of Threat Stack have been included in the Company's consolidated financial statements from the date of acquisition.  The allocated purchase consideration to assets acquired and liabilities assumed based on preliminary estimated fair values is presented in the following table (in thousands): Estimated Useful Life Assets acquired Deferred tax assets $ 14,041 Other net tangible assets acquired, at fair value 5,481 Cash, cash equivalents, and restricted cash 911 Identifiable intangible assets: Developed technology 11,400 5 years Customer relationships 4,400 5 years Goodwill 43,282 Total assets acquired $ 79,515 Liabilities assumed Deferred revenue $ (10,591) Total liabilities assumed $ (10,591) Net assets acquired $ 68,924 The measurement period for the Threat Stack acquisition lapsed during the first quarter of fiscal 2023. The Company recorded immaterial adjustments to consideration exchanged for the purchase of Threat Stack within the post-close measurement period. The developed technology intangible asset is amortized on a straight-line basis over its estimated useful life of five years and included in cost of net product revenues. The customer relationships intangible asset is amortized on a straight-line basis over its estimated useful life of five years and included in sales and marketing expenses. The weighted-average life of the amortizable intangible assets recognized from the Threat Stack acquisition was five years as of October 1, 2021, the date the transaction closed. The estimated useful lives for the acquired intangible assets were based on the expected future cash flows associated with the respective asset. The pro forma financial information, as well as the revenue and earnings generated by Threat Stack, were not material to the Company's operations for the periods presented. Fiscal Year 2021 Acquisition of Volterra, Inc. On January 5, 2021, the Company entered into a Merger Agreement (the “Volterra Merger Agreement”) with Volterra, Inc. ("Volterra"), a provider of edge-as-a-service platform solutions. The transaction closed on January 22, 2021 with Volterra becoming a wholly-owned subsidiary of F5. With the addition of Volterra’s technology platform, F5 is creating an edge platform built for enterprises and service providers that will be security-first and app-driven with unlimited scale. Pursuant to the Volterra Merger Agreement, at the effective time of the Merger, the capital stock of Volterra and the vested outstanding and unexercised stock options in Volterra were cancelled and converted to the right to receive $427.2 million in cash, subject to certain adjustments and conditions set forth in the Volterra Merger Agreement. The unvested stock options and restricted stock units in Volterra held by continuing employees of Volterra were assumed by F5, on the terms and conditions set forth in the Volterra Merger Agreement. The Company incurred $9.5 million of transaction costs associated with the acquisition which was included in General and Administrative expenses in fiscal 2021. As a result of the acquisition, the Company acquired all the assets and assumed all the liabilities of Volterra. The goodwill related to the Volterra acquisition is comprised primarily of expected synergies from combining operations and the acquired intangible assets that do not qualify for separate recognition. Goodwill related to the Volterra acquisition was not deductible for tax purposes. The results of operations of Volterra have been included in the Company's consolidated financial statements from the date of acquisition. The allocated purchase consideration to assets acquired and liabilities assumed based on preliminary estimated fair values is presented in the following table (in thousands): Estimated Useful Life Assets acquired Cash, cash equivalents, and restricted cash $ 14,012 Other tangible assets acquired, at fair value 7,499 Identifiable intangible assets: Developed technology 59,500 7 years Customer relationships 500 1 year Goodwill 350,863 Total assets acquired 432,374 Liabilities assumed (5,233) Net assets acquired $ 427,141 The measurement period for the Volterra acquisition lapsed during the second quarter of fiscal 2022. The Company recorded immaterial adjustments to consideration exchanged for the purchase of Volterra within the post-close measurement period. The developed technology intangible asset is being amortized on a straight-line basis over its estimated useful life of seven years and included in cost of net product revenues. The customer relationships intangible asset was amortized on a straight-line basis over its estimated useful life of one year and included in sales and marketing expenses. The weighted-average life of the amortizable intangible assets recognized from the Volterra acquisition was 6.95 years as of January 22, 2021, the date the transaction closed. The estimated useful lives for the acquired intangible assets were based on the expected future cash flows associated with the respective asset. The pro forma financial information, as well as the revenue and earnings generated by Volterra, were not material to the Company's operations for the periods presented.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value MeasurementsIn accordance with the authoritative guidance on fair value measurements and disclosure under GAAP, the Company determines fair value using a fair value hierarchy that distinguishes between market participant assumptions developed based on market data obtained from sources independent of the reporting entity, and the reporting entity’s own assumptions about market participant assumptions developed based on the best information available in the circumstances and expands disclosure about fair value measurements. Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date, essentially the exit price. The levels of fair value hierarchy are: Level 1: Quoted prices in active markets for identical assets and liabilities at the measurement date that the Company has the ability to access. Level 2: Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. Level 3: Unobservable inputs for which there is little or no market data available. These inputs reflect management’s assumptions of what market participants would use in pricing the asset or liability. Level 1 investments are valued based on quoted market prices in active markets and include the Company’s cash equivalent investments. Level 2 investments, which include investments that are valued based on quoted prices in markets that are not active, broker or dealer quotations, actual trade data, benchmark yields or alternative pricing sources with reasonable levels of price transparency, include the Company’s certificates of deposit, corporate bonds and notes, municipal bonds and notes, U.S. government securities, U.S. government agency securities and international government securities. Fair values for the Company’s level 2 investments are based on similar assets without applying significant judgments. In addition, all of the Company’s level 2 investments have a sufficient level of trading volume to demonstrate that the fair values used are appropriate for these investments. A financial instrument’s level within the fair value hierarchy is based upon the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis The Company's financial assets measured at fair value on a recurring basis subject to the disclosure requirements at September 30, 2023 and 2022, were as follows (in thousands): Gross Unrealized Classification on Balance Sheet As of September 30, 2023 Fair Value Level Cost or Amortized Cost Gains Losses Aggregate Cash and Cash Equivalents Short-Term Investments Long-Term Investments Changes in fair value recorded in other comprehensive income Money Market Funds Level 1 $ 392,592 $ — $ — $ 392,592 $ 392,592 $ — $ — Corporate bonds and notes Level 2 4,412 — (88) 4,324 — 4,324 — Municipal bonds and notes Level 2 1,108 — (9) 1,099 — 1,099 — U.S. government securities Level 2 — — — — — — — U.S. government agency securities Level 2 740 — (3) 737 — 737 — Total debt investments $ 398,852 $ — $ (100) $ 398,752 $ 392,592 $ 6,160 $ — Changes in fair value recorded in other net income (expense) Equity investments * $ 5,068 $ — $ — $ 5,068 Total equity investments 5,068 — — 5,068 Total investments $ 403,820 $ 392,592 $ 6,160 $ 5,068 * The fair value of this equity investment is measured at net asset value (NAV) which approximates fair value and is not classified within the fair value hierarchy . Gross Unrealized Classification on Balance Sheet As of September 30, 2022 Fair Value Level Cost or Amortized Cost Gains Losses Aggregate Cash and Cash Equivalents Short-Term Investments Long-Term Investments Changes in fair value recorded in other comprehensive income Money Market Funds Level 1 $ 276,294 $ — $ — $ 276,294 $ 276,294 $ — $ — Corporate bonds and notes Level 2 50,828 — (950) 49,878 912 44,356 4,610 Municipal bonds and notes Level 2 5,018 — (102) 4,916 — 3,812 1,104 U.S. government securities Level 2 84,734 — (660) 84,074 10,120 73,954 — U.S. government agency securities Level 2 5,825 — (75) 5,750 606 4,432 712 Total debt investments $ 422,699 $ — $ (1,787) $ 420,912 $ 287,932 $ 126,554 $ 6,426 Changes in fair value recorded in other net income (expense) Equity investments * $ 3,118 $ — $ — $ 3,118 Total equity investments 3,118 — — 3,118 Total investments $ 424,030 $ 287,932 $ 126,554 $ 9,544 * The fair value of this equity investment is measured at NAV which approximates fair value and is not classified within the fair value hierarchy . The Company uses the fair value hierarchy for financial assets and liabilities. The carrying amounts of other current financial assets and other current financial liabilities approximate fair value due to their short-term nature. Interest income from investments was not material for the years ended September 30, 2023, 2022, and 2021. Interest income is included in other income (expense), net on the Company's consolidated income statements. Unrealized losses on investments held for a period greater than 12 months at September 30, 2023 and 2022 were not material. The Company invests in debt securities that are rated investment grade. The Company reviews the individual debt securities in its portfolio to determine whether a credit loss exists by comparing the extent to which the fair value is less than the amortized cost and considering any changes to ratings of a debt security by a ratings agency. The Company determined that as of September 30, 2023, there were no credit losses on any investments within its portfolio. Assets Measured and Recorded at Fair Value on a Non-Recurring Basis The Company’s non-financial long-lived assets, which include goodwill and other intangible assets, are not required to be carried at fair value on a recurring basis. These non-financial assets are measured at fair value on a non-recurring basis when there is an indicator of impairment, and they are recorded at fair value only when impairment is recognized. The Company reviews goodwill for impairment annually, during the second quarter of each fiscal year, or as circumstances indicate the possibility of impairment. The Company monitors the carrying value of tangible and intangible long-lived assets for impairment whenever events or changes in circumstances indicate its carrying amount may not be recoverable. During the year ended September 30, 2023, the Company recorded an impairment of $3.5 million against the operating lease right-of-use asset related to its third quarter of fiscal 2023 restructuring plan, see Note 13, Restructuring Charges. The charge was reflected in the Restructuring Charges line item on the Company's consolidated income statement. During the year ended September 30, 2022, as a result of a planned change in the use of the asset, the Company recorded an impairment of $6.2 million against the Shape trade name intangible asset, which was reflected in the Sales and Marketing line item on the Company's consolidated income statement. During the year ended September 30, 2021, the Company recorded an impairment of $23.5 million against the operating lease right-of-use asset related to the permanent exit of six floors in its corporate headquarters and $10.3 million for tenant improvements and other fixed assets associated with the exited floors. The Company also recorded an impairment of $6.7 million against the operating lease right-of-use asset related to the integration of the former Shape headquarters in Santa Clara, California and $0.2 million for other fixed assets associated with the impaired Shape headquarters. The Company calculated the fair value of the right-of-use assets, tenant improvements and other fixed assets based on estimated future discounted cash flows and classified the fair value as a Level 3 measurement due to the significance of unobservable inputs, which included the amount and timing of estimated sublease rental receipts that the Company could reasonably obtain over the remaining lease term and the discount rate. The impairment charges for the year ended September 30, 2021 were allocated to various expense line items on the Company’s consolidated income statements based on the teams that previously worked out of the exited space. Impairment charges were allocated to the following income statement line items for the years ended September 30, 2023, 2022, and 2021 (in thousands): Years Ended September 30, 2023 2022 2021 Cost of net product revenue $ — $ — $ 2,865 Cost of net service revenue — — 3,492 Sales and marketing — 6,175 11,515 Research and development — — 12,974 General and administrative — — 9,852 Restructuring charges 3,455 — — Total impairment charges $ 3,455 $ 6,175 $ 40,698 The Company did not recognize any other impairment charges related to non-financial long-lived assets for the years ended September 30, 2023, 2022, and 2021.

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Sep. 30, 2023
Balance Sheet Details [Abstract]
Balance Sheet Details	Balance Sheet Details Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of the Company’s cash and cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash shown in the Company’s consolidated statements of cash flows for the periods presented (in thousands): September 30, 2023 2022 Cash and cash equivalents $ 797,163 $ 758,012 Restricted cash included in other assets, net 3,672 4,195 Total cash, cash equivalents and restricted cash $ 800,835 $ 762,207 Inventories Inventories consist of the following (in thousands): September 30, 2023 2022 Finished goods $ 11,699 $ 10,164 Raw materials 24,175 58,201 $ 35,874 $ 68,365 Other Current Assets Other current assets consist of the following (in thousands): September 30, 2023 2022 Unbilled receivables $ 374,113 $ 319,707 Prepaid expenses 84,506 57,340 Capitalized contract acquisition costs 31,206 34,658 Other 1 64,919 77,609 $ 554,744 $ 489,314 (1) As of September 30, 2023 and 2022, includes a deposit of $36.2 million and $57.0 million, respectively, used to support the working capital needs of the Company’s primary contract manufacturer's procurement of components used in the manufacturing of system hardware. Property and Equipment Property and equipment consist of the following (in thousands): September 30, 2023 2022 Computer equipment $ 189,555 $ 168,204 Software 78,184 86,036 Office furniture and equipment 44,525 41,619 Leasehold improvements 185,225 173,689 497,489 469,548 Accumulated depreciation and amortization (327,067) (301,366) $ 170,422 $ 168,182 Depreciation and amortization expense totaled approximately $53.3 million, $56.0 million, and $61.3 million for the fiscal years ended September 30, 2023, 2022 and 2021, respectively. There were no property and equipment impairment charges for the years ended September 30, 2023 and 2022, respectively. During the year ended September 30, 2021, the Company recorded an impairment of $10.3 million for leasehold improvements and other fixed assets associated with the permanent exit of six floors in its corporate headquarters. The Company also recorded an impairment of $0.2 million for fixed assets associated with the integration of the former Shape headquarters in Santa Clara, California. The impairment charges for the year ended September 30, 2021 were allocated to various expense line items on the Company’s consolidated income statements based on the teams that previously worked out of the exited space. Goodwill Changes in the carrying amount of goodwill during fiscal years 2023 and 2022 are summarized as follows (in thousands): Balance, September 30, 2021 $ 2,216,553 Acquisition of Threat Stack, Inc. 43,956 Other (1,227) Balance, September 30, 2022 2,259,282 Other business acquisitions 29,396 Balance, September 30, 2023 $ 2,288,678 Other Assets Other assets consist of the following (in thousands): September 30, 2023 2022 Intangible assets $ 150,969 $ 200,288 Unbilled receivables 202,838 224,780 Capitalized contract acquisition costs 35,263 42,561 Other 55,543 48,493 $ 444,613 $ 516,122 Intangible assets are included in other assets on the consolidated balance sheets and consist of the following (in thousands): September 30, 2023 September 30, 2022 Gross Accumulated Net Carrying Gross Accumulated Net Carrying Developed technology $ 319,368 $ (190,135) $ 129,233 $ 319,436 $ (151,332) $ 168,104 Customer relationships 45,642 (33,298) 12,344 46,142 (25,630) 20,512 Patents and trademarks 13,699 (9,658) 4,041 23,504 (19,255) 4,249 Trade names 15,473 (10,122) 5,351 24,973 (17,550) 7,423 Non-compete covenants 1,960 (1,960) — 2,260 (2,260) — $ 396,142 $ (245,173) $ 150,969 $ 416,315 $ (216,027) $ 200,288 There were no intangible asset impairment charges for the year ended September 30, 2023. During the year ended September 30, 2022, as a result of a planned change in the use of the asset, the Company recorded an impairment of $6.2 million against the Shape trade name intangible asset, which was reflected in the Sales and Marketing line item on the Company's consolidated income statement. Amortization expense related to intangible assets was $29.1 million, $36.4 million, and $48.7 million for the fiscal years ended September 30, 2023, 2022 and 2021, respectively. For intangible assets held as of September 30, 2023, amortization expense for the five succeeding fiscal years is as follows (in thousands): 2024 $ 50,914 2025 39,477 2026 34,723 2027 16,541 2028 4,106 $ 145,761 Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, 2023 2022 Payroll and benefits $ 152,898 $ 165,437 Operating lease liabilities, current 41,421 42,523 Income and other tax accruals 34,504 41,217 Other 54,067 60,642 $ 282,890 $ 309,819 Other Long-term Liabilities Other long-term liabilities consist of the following (in thousands): September 30, 2023 2022 Income taxes payable $ 73,751 $ 59,553 Other 8,822 8,157 $ 82,573 $ 67,710

Debt Facilities

Debt Facilities	12 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt Facilities	Debt Facilities Term Credit Agreement In connection with the acquisition of Shape, on January 24, 2020, the Company entered into a Term Credit Agreement ("Term Credit Agreement") with certain institutional lenders that provides for a senior unsecured term loan facility in an aggregate principal amount of $400.0 million (the "Term Loan Facility"). The Term Loan Facility had an original maturity date of January 24, 2023 with quarterly installments equal to 1.25% of the original principal amount. Borrowings under the Term Loan Facility bore interest at a rate equal to LIBOR, plus an applicable margin of 1.125% to 1.75% depending on the Company's leverage ratio. The proceeds from the Term Loan Facility were primarily used to finance the acquisition of Shape and related expenses. In connection with the Term Loan Facility, the Company incurred $2.2 million in debt issuance costs, which were recorded as a reduction to the carrying value of the principal amount of the debt. On December 15, 2022, the Company voluntarily prepaid, in full, all borrowings under the Term Loan Facility, including the outstanding principal balance of $350.0 million, and all accrued, but unpaid interest outstanding of $3.0 million. All remaining debt issuance costs were amortized to interest expense associated with the prepayment. As a result of the payoff of its Term Loan Facility, the Company was released of any and all obligations, maintenance of covenants, and indebtedness under the Term Credit Agreement. The weighted average interest rate on the principal amount under the Term Loan Facility outstanding balance was 4.072% for the period of October 1, 2022 to December 15, 2022. As of September 30, 2022, $350.0 million of principal amount under the Term Loan Facility was outstanding, excluding unamortized debt issuance costs of $0.2 million. The outstanding principal amount was included in current liabilities on the Company's consolidated balance sheet as of September 30, 2022. The weighted average interest rate on the principal amount under the Term Loan Facility outstanding balance was 2.190% and 1.361% for the fiscal years ended September 30, 2022 and 2021, respectively. Revolving Credit Agreement On January 31, 2020, the Company entered into a Revolving Credit Agreement (the "Revolving Credit Agreement") that provides for a senior unsecured revolving credit facility in an aggregate principal amount of $350.0 million (the "Revolving Credit Facility"). The Company has the option to increase commitments under the Revolving Credit Facility from time to time, subject to certain conditions, by up to $150.0 million. Historically, borrowings under the Revolving Credit Facility bore interest at a rate equal to, at the Company's option, (a) LIBOR, adjusted for customary statutory reserves, plus an applicable margin of 1.125% to 1.75% depending on the Company's leverage ratio, or (b) an alternate base rate determined in accordance with the Revolving Credit Agreement, plus an applicable margin of 0.125% to 0.750% depending on the Company's leverage ratio. On May 26, 2023, the Company amended the Revolving Credit Agreement as a result of the cessation of the LIBOR borrowing reference rate. The amendment modified and directly replaced the LIBOR borrowing reference rate within the Revolving Credit Agreement to the Secured Overnight Financing Rate ("SOFR"). After the amendment, borrowings under the Revolving Credit

Leases

Leases	12 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	Leases The majority of the Company's operating lease payments relate to its corporate headquarters in Seattle, Washington, which includes approximately 515,000 square feet of office space. The lease commenced in April 2019 and expires in 2033 with an option for renewal. The Company also leases additional office and lab space for product development and sales and support personnel in the United States and internationally. The Company's lease agreements do not contain any material residual value guarantees or material restrictive covenants. The components of the Company's operating lease expenses for the years ended September 30, 2023, 2022, and 2021 were as follows (in thousands): Fiscal year ended September 30, 2023 2022 2021 Operating lease expense $ 47,036 $ 47,302 $ 47,993 Short-term lease expense 2,986 2,465 2,953 Variable lease expense 23,139 23,209 25,200 Total lease expense $ 73,161 $ 72,976 $ 76,146 Variable lease expense primarily consists of common area maintenance, real estate taxes and parking expenses. Supplemental balance sheet information related to the Company's operating leases was as follows (in thousands, except lease term and discount rate): September 30, 2023 2022 Operating lease right-of-use assets, net $ 195,471 $ 227,475 Operating lease liabilities, current 1 41,421 42,523 Operating lease liabilities, long-term 239,565 272,376 Total operating lease liabilities $ 280,986 $ 314,899 Weighted average remaining lease term (in years) 8.6 9.2 Weighted average discount rate 2.77 % 2.66 % (1) Current portion of operating lease liabilities is included in accrued liabilities on the Company's consolidated balance sheets. As of September 30, 2023, the future operating leases payments for each of the next five years and thereafter is as follows (in thousands): Fiscal Years Ending September 30: Operating Lease 2024 $ 48,709 2025 41,095 2026 31,559 2027 30,394 2028 28,340 Thereafter 138,797 Total lease payments 318,894 Less: imputed interest (37,908) Total lease liabilities $ 280,986 Operating lease liabilities above do not include sublease income. As of September 30, 2023, the Company expects to receive sublease income of approximately $14.7 million, which consists of $7.3 million to be received in fiscal year 2024 and $7.4 million to be received over the two fiscal years thereafter. During the year ended September 30, 2023, the Company recorded an impairment of $3.5 million against the operating lease right-of-use asset related to its third quarter of fiscal 2023 restructuring plan, see Note 13, Restructuring Charges. There were no impairments against right-of-use assets for the year ended September 30, 2022. During the year ended September 30, 2021, the Company recorded an impairment of $23.5 million against the operating lease right-of-use asset related to the exit of six floors in its corporate headquarters. The Company also recorded an impairment of $6.7 million against the right-of-use asset related to the integration of the former Shape headquarters in Santa Clara, California. As of September 30, 2023, the Company had no significant operating leases that were executed but not yet commenced.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The United States and international components of income before income taxes are as follows (in thousands): Years Ended September 30, 2023 2022 2021 United States $ 268,314 $ 217,323 $ 189,398 International 217,674 168,070 197,539 $ 485,988 $ 385,393 $ 386,937 The provision for income taxes consists of the following (in thousands): Years Ended September 30, 2023 2022 2021 Current U.S. federal $ 115,170 $ 35,259 $ 53,107 State 18,359 14,592 16,686 Foreign 66,053 54,079 62,832 Total 199,582 103,930 132,625 Deferred U.S. federal (89,280) (28,721) (61,739) State (18,576) (11,332) (15,294) Foreign (686) (644) 104 Total (108,542) (40,697) (76,929) $ 91,040 $ 63,233 $ 55,696 The effective tax rate differs from the U.S. federal statutory rate as follows (in thousands): Years Ended September 30, 2023 2022 2021 Income tax provision at statutory rate $ 102,058 $ 80,933 $ 81,257 State taxes, net of federal benefit 6,806 6,012 5,118 Tax impact of foreign operations (20,230) (21,435) (26,881) Research and development and other credits (19,198) (18,917) (18,055) Stock-based and other compensation 20,145 15,070 12,740 Other 1,459 1,570 1,517 $ 91,040 $ 63,233 $ 55,696 The Company does not maintain an indefinite reinvestment assertion on unremitted foreign earnings and has recorded a deferred tax liability for any estimated foreign, federal, or state tax liabilities associated with a future repatriation of foreign earnings. The Company benefits from tax incentive arrangements in certain foreign jurisdictions, one of which expired in fiscal year 2021 and the rest of which expire in fiscal years 2026 to 2034. The tax incentive agreements are conditional upon meeting certain operational, employment, and investment requirements. These arrangements decreased foreign taxes by $6.0 million, $8.5 million and $6.0 million, and increased diluted earnings per common share by $0.10, $0.14 and $0.10 for the years ended September 30, 2023, 2022 and 2021, respectively. The tax effects of the temporary differences that give rise to the deferred tax assets and liabilities are as follows (in thousands): Years Ended September 30, 2023 2022 Deferred tax assets Net operating loss carry-forwards $ 40,201 $ 42,849 Capitalized research and development costs 267,744 158,206 Accrued compensation and benefits 11,995 14,068 Stock-based compensation 8,875 10,389 Deferred revenue 42,544 32,244 Lease liabilities 62,405 67,520 Other accruals and reserves 22,723 18,797 Tax credit carryforwards 23,883 28,858 Depreciation 531 505 480,901 373,436 Valuation allowance (43,942) (46,136) 436,959 327,300 Deferred tax liabilities Purchased intangibles (55,519) (57,350) Depreciation (28,113) (22,278) Deferred costs (11,031) (12,987) Lease assets (41,709) (45,948) Other accruals and reserves (9,916) (8,153) (146,288) (146,716) Net deferred tax assets $ 290,671 $ 180,584 At September 30, 2023, the Company had foreign net operating loss carryforwards of approximately $56.9 million that can be carried forward indefinitely, and $0.3 million that will expire in fiscal years 2038 to 2039. The Company had $79.8 million of federal net operating loss carryforwards, of which $56.4 million can be carried forward indefinitely and $23.4 million that will expire in fiscal years 2033 to 2038. The annual utilization of the federal net operating loss carryforwards is limited under Internal Revenue Code Section 382. The Company also had $238.8 million of state net operating loss carryforwards, of which $47.0 million can be carried forward indefinitely and $191.8 million will expire in fiscal years 2029 to 2043. In addition, there are $0.2 million of foreign credit carryforwards that can be carried forward indefinitely, $3.2 million of foreign credit carryforwards that will expire in fiscal years 2024 to 2039, $3.2 million of federal credit carryforwards that will expire in fiscal years 2033 to 2041, $30.2 million of state tax credit carryforwards that can be carried forward indefinitely, and $3.7 million of state tax credit carryforwards that will expire in fiscal years 2032 to 2038. Management believes that it is more likely than not that the benefit from certain foreign net operating loss and credit carryforwards and state tax net operating loss and credit carryforwards will not be realized. In recognition of this risk, the Company has provided a valuation allowance on the deferred tax assets relating to these carryforwards. The net change in the total valuation allowance was a decrease of $2.2 million and an increase of $5.7 million for years ended September 30, 2023 and 2022, respectively. The Company recognizes the financial statement impact of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the financial statements is the largest impact that has a greater than fifty percent likelihood of being realized upon ultimate settlement with the relevant tax authority. The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits in fiscal years 2023, 2022 and 2021 (in thousands): 2023 2022 2021 Balance, beginning of period $ 66,840 $ 70,814 $ 51,767 Gross increases related to prior period tax positions 4,270 4,816 14,867 Gross decreases related to prior period tax positions (70) (10,538) — Gross increases related to current period tax positions 9,224 10,203 12,595 Decreases relating to settlements with tax authorities (300) — (321) Reductions due to lapses of statute of limitations (797) (8,455) (8,094) Balance, end of period $ 79,167 $ 66,840 $ 70,814 The total amount of gross unrecognized tax benefits was $79.2 million, $66.8 million, and $70.8 million as of September 30, 2023, 2022, and 2021, respectively, of which, $51.2 million, $43.2 million, and $39.2 million, if recognized, would affect the effective tax rate. There is a reasonable possibility that the Company’s unrecognized tax benefits will change within twelve months due to audit settlements or the expiration of statute of limitations, but the Company does not expect the change to be material to the consolidated financial statements. The Company recognizes interest and, if applicable, penalties (not included in the “unrecognized tax benefits” table above) for any uncertain tax positions. Interest and penalties are recorded as a component of income tax expense. In the years ended September 30, 2023, 2022 and 2021, the Company recorded approximately a $3.3 million increase, $1.5 million decrease and $1.4 million increase, respectively, of interest and penalty expense related to uncertain tax positions. As of September 30, 2023 and 2022, the Company had a cumulative balance of accrued interest and penalties on unrecognized tax positions of $6.2 million and $2.9 million, respectively. The Company and its subsidiaries are subject to U.S. federal income tax as well as the income tax of multiple state and foreign jurisdictions. The Company has concluded all U.S. federal income tax matters for fiscal years through September 30, 2018. Major jurisdictions where there are wholly owned subsidiaries of F5, Inc. which require income tax filings include the United Kingdom, Singapore, Israel, and India. The earliest periods open for review by local taxing authorities are fiscal years 2022 for the United Kingdom, 2018 for Singapore, 2013 for Israel, and 2018 for India. The Company is currently under audit by the Internal Revenue Service for fiscal year 2019, by various states for fiscal years 2015 through 2022, and by various foreign jurisdictions including India for fiscal years 2018 to 2022, Israel for fiscal years 2013 to 2017, Saudi Arabia for fiscal years 2015 to 2020, and Singapore for fiscal years 2019 to 2020.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Stockholders' Equity	Shareholders' Equity Common Stock Repurchase On July 25, 2022, the Company announced that its Board of Directors authorized an additional $1.0 billion for its common stock share repurchase program. This authorization is incremental to the existing $5.4 billion program, initially approved in October 2010 and expanded in subsequent fiscal years. Acquisitions for the share repurchase programs will be made from time to time in private transactions, accelerated share repurchase programs, or open market purchases as permitted by securities laws and other legal requirements. The programs can be terminated at any time. On February 3, 2021, the Company entered into Accelerated Share Repurchase ("ASR") agreements with two financial institutions under which the Company paid an aggregate of $500 million. The ASR agreements were accounted for as two separate transactions (1) a repurchase of common stock and (2) an equity-linked contract on the Company's own stock. Upon execution of the ASR agreements, the Company received an initial delivery of 2.1 million shares for an aggregate price of $400 million, based on the market price of $194.91 per share of the Company's common stock on the date of the transaction. The initial shares received by the Company were retired immediately upon receipt. The equity-linked contract for the remaining $100 million, representing remaining shares to be delivered by the financial institutions under the ASR agreements, was recorded to common stock as of March 31, 2021 and was settled in the third quarter of fiscal 2021 with the Company receiving 449,049 additional shares, which were retired immediately upon receipt. The total ASR resulted in a repurchase of 2.5 million shares of the Company's common stock at a volume weighted average repurchase price, less an agreed upon discount, of $199.90 per share. The shares received by the Company were retired, accounted for as a reduction to stockholder’s equity in the consolidated balance sheets, and treated as a repurchase of common stock for purposes of calculating earnings per share. The Company was not required to make any additional cash payments or delivery of common stock to the financial institutions upon settlement of the agreements. The following table summarizes the Company's repurchases and retirements of its common stock under its Stock Repurchase Program, including the ASR (in thousands, except per share data): Years Ended September 30, 2023 2022 2021 Shares repurchased 2,454 2,611 2,501 Average price per share $ 142.62 $ 191.47 $ 199.90 Amount repurchased $ 350,049 $ 500,023 $ 500,000 As of September 30, 2023, the Company had $922 million remaining authorized to purchase shares under its share repurchase program.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Stock-Based Compensation	Stock-based Compensation The Company recognized $236.7 million, $249.2 million and $243.3 million of stock-based compensation expense for the fiscal years ended September 30, 2023, 2022 and 2021, respectively. The income tax benefit recognized on stock-based compensation within income tax expense was $44.7 million, $47.3 million and $44.1 million for the fiscal years ended September 30, 2023, 2022 and 2021, respectively. As of September 30, 2023, there was $162.7 million of total unrecognized stock-based compensation cost, the substantial majority of which will be recognized over approximately two years. Going forward, stock-based compensation expenses may increase as the Company issues additional equity-based awards to continue to attract and retain key employees. On October 31, 2023, the Company’s Board of Directors and Talent and Compensation Committee approved 1,256,510 RSUs to employees and executive officers pursuant to the Company’s annual equity awards program. Company has adopted a number of stock-based compensation plans as discussed below. 2011 Employee Stock Purchase Plan. In April 2012, the Board of Directors amended and restated the Company’s 1999 Employee Stock Purchase Plan, or the Employee Stock Purchase Plan. A total of 12,000,000 shares of common stock have been reserved for issuance under the Employee Stock Purchase Plan. The Employee Stock Purchase Plan permits eligible employees to acquire shares of the Company’s common stock through periodic payroll deductions of up to 15% of base compensation. No employee may purchase more than 10,000 shares during an offering period. In addition, no employee may purchase more than $25,000 worth of stock, determined by the fair market value of the shares at the time such option is granted, in one calendar year. The Employee Stock Purchase Plan has been implemented in a series of offering periods, each 6 months in duration. The price at which the common stock may be purchased is 85% of the lesser of the fair market value of the Company’s common stock on the first day of the applicable offering period or on the last day of the respective purchase period. As of September 30, 2023 there were 2,444,575 shares available for awards under the Employee Stock Purchase Plan. In determining the fair value of the right to purchase under the Employee Stock Purchase Plan, the Company uses the Black-Scholes option pricing model that employs the following key assumptions: Employee Stock Purchase Plan 2023 2022 2021 Risk-free interest rate 3.18% - 4.90% 0.05% - 0.62% 0.07% - 0.13% Expected dividend — — — Expected term 0.5 years 0.5 years 0.5 years Expected volatility 33.02% - 38.15% 26.34% - 31.57% 29.67% - 37.22% Acquisition Related Incentive Plans. In May 2019, the Company adopted the Nginx Acquisition Equity Incentive Plan, or the Nginx Acquisition Plan. The Nginx Acquisition Plan provided for discretionary grants of stock options and stock units for employees, directors and consultants of Nginx, Inc. to whom the Company offered employment in connection with the Company’s acquisition of Nginx. A total of 183,061 shares of common stock were reserved for issuance under the Nginx Acquisition Plan. Upon certain changes in control of the Company, the surviving entity will either assume or substitute all outstanding stock awards under the Nginx Acquisition Plan or the vesting of 50% of the stock awards shall be accelerated. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Nginx Acquisition Plan. As of September 30, 2023, there were no options outstanding and 19 stock units outstanding. The Company terminated the Nginx Acquisition Plan effective October 31, 2019 and no additional shares may be issued from the Nginx Acquisition Plan. In connection with the Company’s acquisition of Nginx, Inc. in the third quarter of fiscal year 2019, the Company assumed the Nginx Inc. 2011 Share Plan, or the Nginx Plan. Unvested options to acquire Nginx's common stock and unvested stock units with respect to Nginx’s common stock were converted into options to acquire the Company’s common stock and stock units with respect to the Company’s stock in connection with the acquisition. A total of 302,634 shares of common stock were reserved for issuance under the Nginx Plan (including converted options and stock units). The Nginx Plan provided for grants of stock options, stock awards and stock units to persons who were employees, officers, directors and consultants to Nginx, Inc. prior to May 8, 2019. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Nginx Plan. As of September 30, 2023, there were options to purchase 6,010 shares outstanding and no stock units outstanding. The Company terminated the Nginx Plan effective October 31, 2019 and no additional shares may be issued from the Nginx Plan. In January 2020, the Company adopted the Shape Acquisition Equity Incentive Plan, or the Shape Acquisition Plan. The Shape Acquisition Plan provided for discretionary grants of stock options and stock units for employees, directors and consultants of Shape Security, Inc. to whom the Company offered employment in connection with the Company’s acquisition of Shape. A total of 450,000 shares of common stock were reserved for issuance under the Shape Acquisition Plan. Upon certain changes in control of the Company, the surviving entity will either assume or substitute all outstanding stock awards under the Shape Acquisition Plan or the vesting of 50% of the stock awards shall be accelerated. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Shape Acquisition Plan. As of September 30, 2023, there were no options outstanding and 20,754 stock units outstanding. The Company terminated the Shape Acquisition Plan effective December 28, 2020 and no additional shares may be issued from the Shape Acquisition Plan. In connection with the Company’s acquisition of Shape Security, Inc. in the second quarter of fiscal year 2020, the Company assumed the Shape 2011 Stock Plan, or the Shape Plan. Unvested options to acquire Shape’s common stock and unvested stock units with respect to Shape’s common stock were converted into options to acquire the Company’s common stock and stock units with respect to the Company’s stock in connection with the acquisition. A total of 501,085 shares of common stock were reserved for issuance under the Shape Plan (including converted options and stock units). The Shape Plan provided for grants of stock options, stock awards and stock units to persons who were employees, officers, directors and consultants to Shape Security, Inc. prior to January 24, 2020. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Shape Plan. As of September 30, 2023, there were options to purchase 51,144 shares outstanding and no stock units outstanding. The Company terminated the Shape Plan effective December 28, 2020 and no additional shares may be issued from the Shape Plan. In January 2021, the Company adopted the Volterra Acquisition Equity Incentive Plan, or the Volterra Acquisition Plan. The Volterra Acquisition Plan provided for discretionary grants of stock options and stock units for employees, directors and consultants of Volterra, Inc. to whom the Company offered employment in connection with the Company’s acquisition of Volterra. A total of 140,000 shares of common stock were reserved for issuance under the Volterra Acquisition Plan. Upon certain changes in control of the Company, the surviving entity will either assume or substitute all outstanding stock awards under the Volterra Acquisition Plan or the vesting of 50% of the stock awards shall be accelerated. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Volterra Acquisition Plan. As of September 30, 2023, there were no options outstanding and 39,472 stock units outstanding. The Company terminated the Volterra Acquisition Plan effective October 29, 2021 and no additional shares may be issued from the Volterra Acquisition Plan. In connection with the Company’s acquisition of Volterra, Inc. in the second quarter of fiscal year 2021, the Company assumed the Volterra 2017 Stock Plan, or the Volterra Plan. Unvested options to acquire Volterra’s common stock and unvested stock units with respect to Volterra’s common stock were converted into options to acquire the Company’s common stock and stock units with respect to the Company’s stock in connection with the acquisition. A total of 261,696 shares of common stock were reserved for issuance under the Volterra Plan (including converted options and stock units). The Volterra Plan provided for grants of stock options, stock awards and stock units to persons who were employees, officers, directors and consultants to Volterra, Inc. prior to January 22, 2021. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Volterra Plan. As of September 30, 2023, there were options to purchase 46,778 shares outstanding and 7,171 stock units outstanding. The Company terminated the Volterra Plan effective October 29, 2021 and no additional shares may be issued from the Volterra Plan. In November 2021, the Company adopted the Threat Stack Acquisition Equity Incentive Plan, or the Threat Stack Acquisition Plan. The Threat Stack Acquisition Plan provided for discretionary grants of stock options and stock units for employees, directors and consultants of Threat Stack to whom the Company offered employment in connection with the Company’s acquisition of Threat Stack. A total of 35,000 shares of common stock were reserved for issuance under the Threat Stack Acquisition Plan. Upon certain changes in control of the Company, the surviving entity will either assume or substitute all outstanding stock awards under the Threat Stack Acquisition Plan or the vesting of 50% of the stock awards shall be accelerated. During the fiscal year 2023, the Company issued no stock options or restricted stock units under the Threat Stack Acquisition Plan. As of September 30, 2023, there were no options outstanding and 6,915 stock units outstanding. The Company terminated the Threat Stack Acquisition Equity Incentive Plan effective January 10, 2022 and no additional shares may be issued from the Threat Stack Acquisition Plan. In February 2023, the Company adopted the Lilac Acquisition Equity Incentive Plan, or the Lilac Acquisition Plan. The Lilac Acquisition Plan provided for discretionary grants of stock options and stock units for employees, directors and consultants of Lilac Cloud, Inc. to whom the Company offered employment in connection with the Company’s acquisition of Lilac. A total of 55,000 shares of common stock were reserved for issuance under the Lilac Acquisition Plan. Upon certain changes in control of the Company, the surviving entity will either assume or substitute all outstanding stock awards under the Lilac Acquisition Plan or the vesting of 50% of the stock awards shall be accelerated. During the fiscal year 2023, the Company issued no stock options and 47,904 restricted stock units under the Lilac Acquisition Plan. As of September 30, 2023, there were no options outstanding and 47,904 stock units outstanding. The Company terminated the Lilac Acquisition Plan effective October 31, 2023 and no additional shares may be issued from the Lilac Acquisition Plan. In connection with the Company’s acquisition of Lilac Cloud, Inc. in the second quarter of fiscal year 2023, the Company assumed the Lilac Cloud 2018 Equity Incentive Plan, or the Lilac Plan. Unvested options to acquire Lilac’s common stock and unvested stock units with respect to Lilac’s common stock were converted into options to acquire the Company’s common stock and stock units with respect to the Company’s stock in connection with the acquisition. A total of 4,485 shares of common stock were reserved for issuance under the Lilac Plan (including converted options and stock units). The Lilac Plan provided for grants of stock options, stock awards and stock units to persons who were employees, officers, directors and consultants to Lilac Cloud, Inc. prior to February 1, 2023. During the fiscal year 2023, the Company issued 2,051 stock options and no restricted stock units under the Lilac Plan. As of September 30, 2023, there were options to purchase 1,936 shares outstanding and no stock units outstanding. The Company terminated the Lilac Plan effective October 31, 2023 and no additional shares may be issued from the Lilac Plan. F5, Inc. Incentive Plan. In March 2022, the Company adopted the F5, Inc. Incentive Plan, or the Plan, which amended and restated the 2014 Incentive Plan. The Plan provides for discretionary grants of stock options, stock units and other equity and cash-based awards for employees, including officers, directors and consultants. A total of 27,880,000 shares of common stock have been reserved for issuance under the Plan. Upon certain changes in control of the Company, all outstanding and unvested options or stock awards under the Plan will vest at the rate of 50%, unless assumed or substituted by the acquiring entity. During the fiscal year 2023, the Company issued no stock options, 131,491 performance stock units and 1,448,427 restricted stock units under the Plan. As of September 30, 2023, there were no options outstanding, 199,918 performance stock units outstanding, 1,225,386 restricted stock units outstanding and 5,287,273 shares available for new awards under the Plan. A summary of restricted stock unit activity under the Plan is as follows: Performance Stock Units Restricted Stock Units Outstanding Weighted Outstanding Weighted Balance, September 30, 2022 208,116 $ 169.99 1,137,619 $ 184.59 Units granted 131,491 145.02 1,448,427 145.10 Units vested (92,677) 144.69 (1,113,259) 147.10 Units cancelled (47,012) 171.07 (247,401) 162.80 Balance, September 30, 2023 199,918 $ 159.37 1,225,386 $ 156.89 A majority of the restricted stock units the Company grants to its employees vest quarterly over a two Expected Volatility Fair Value Expected Term Risk-Free Index Expected Grant Date per Share (in years) Interest Rate F5 Members Dividend November 1, 2022 Tranche 1 $ 157.36 0.91 4.66 % 37.17 % 35.56 % — Tranche 2 $ 173.68 1.91 4.51 % 31.84 % 31.74 % — Tranche 3 $ 194.41 2.91 4.44 % 35.50 % 40.59 % — As of September 30, 2023, the following annual equity grants for executive officers or a portion thereof are outstanding: Grant Date RSUs Granted Vesting Schedule Vesting Period Date Fully Vested November 1, 2022 240,808 Quarterly, Annually 1,2 3 years November 1, 2025 November 1, 2021 160,384 Quarterly, Annually 1,2 3 years November 1, 2024 November 2, 2020 257,568 Quarterly, Annually 1 3 years November 1, 2023 November 1, 2019 228,616 Quarterly, Annually 1 3 years November 1, 2022 (1) 50% of the annual equity grant vests in equal quarterly increments and 50% is subject to the Company achieving specified annual performance goals. (2) For the Company's Chief Executive Officer, 40% of the annual equity grant vests in equal quarterly increments and 60% is subject to the Company achieving specified annual performance goals. A summary of stock option activity under all of the Company’s plans is as follows: Options Outstanding Number of Weighted Balance, September 30, 2022 164,796 $ 33.34 Options granted 2,051 4.55 Options exercised (56,516) 26.38 Options cancelled (4,463) 61.35 Balance, September 30, 2023 105,868 $ 35.31 All stock options granted in fiscal years 2023 and 2021 were replacement awards of those assumed as part of business acquisitions. There were no stock options granted in fiscal year 2022. The total intrinsic value of options exercised during fiscal 2023, 2022 and 2021 was $6.9 million, $25.6 million and $25.6 million, respectively. A summary of options outstanding that are exercisable and that have vested and are expected to vest as of September 30, 2023 is as follows: Number of Weighted Weighted Aggregate (In thousands) Stock options outstanding 105,868 5.62 $ 35.31 $ 13,321 Exercisable 99,067 5.54 $ 35.47 $ 12,449 Vested and expected to vest 105,561 5.61 $ 35.36 $ 13,277 (1) Aggregate intrinsic value represents the difference between the fair value of the Company’s common stock underlying these options at September 30, 2023 and the related exercise prices. As of September 30, 2023, equity based awards (including stock options and restricted stock units) are available for future issuance as follows: Awards Balance, September 30, 2022 2,072,778 Granted (1,629,873) Cancelled 349,715 Additional shares reserved (terminated), net 4,504,183 Balance, September 30, 2023 5,296,803

Net Income Per Share

Net Income Per Share	12 Months Ended
	Sep. 30, 2023
Net Income Per Share [Abstract]
Net Income Per Share	Net Income Per ShareBasic net income per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted net income per share is computed by dividing net income by the weighted average number of common and dilutive common stock equivalent shares outstanding during the period. The Company’s nonvested restricted stock units do not have nonforfeitable rights to dividends or dividend equivalents and are not considered participating securities that should be included in the computation of earnings per share under the two-class method. The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share data): Years Ended September 30, 2023 2022 2021 Numerator Net income $ 394,948 $ 322,160 $ 331,241 Denominator Weighted average shares outstanding — basic 59,909 60,274 60,707 Dilutive effect of common shares from stock options and restricted stock units 361 823 1,350 Weighted average shares outstanding — diluted 60,270 61,097 62,057 Basic net income per share $ 6.59 $ 5.34 $ 5.46 Diluted net income per share $ 6.55 $ 5.27 $ 5.34 Anti-dilutive stock-based awards excluded from the calculations of diluted earnings per share were not material for the years ended September 30, 2023, 2022 and 2021.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies Purchase Obligations In October 2022, the Company entered into an unconditional purchase commitment with one of its suppliers for the delivery of systems components. Under the terms of the agreement, the Company is obligated to purchase $10 million of component inventory annually, with a total committed amount of $40 million over a four 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 asserted 26 causes of action against the various defendants, including copyright infringement, violation of trademark law, tortious interference, conspiracy, and fraud. The complaint sought damages, disgorgement of profits, 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 Lynwood’s case. On March 25 and 30, 2021, the Court granted the Company’s and the other defendants’ motions to dismiss with leave to amend. Lynwood filed its amended complaint on April 29, 2021, 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 Court granted the consolidated motion to dismiss without leave to amend on August 16, 2022 and entered final judgment against Lynwood on September 9, 2022. On September 14, 2022, Lynwood filed a notice of appeal to the Ninth Circuit Court of Appeals to appeal the dismissal. Lynwood filed its opening brief on December 16, 2022. The Company filed its opening appellate brief on April 10, 2023, and Lynwood filed its reply on May 31, 2023. Following the Court’s order granting the consolidated motion to dismiss and final judgment in the Company’s favor, the Court subsequently granted the Company attorneys' fees of over $0.8 million, which Lynwood appealed to the Ninth Circuit Court of Appeals. The Appeal is ongoing. Both the dismissal appeal and the fees appeal are set to be heard by the Ninth Circuit Court of Appeals on December 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.

Restructuring Charges

Restructuring Charges	12 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges In the third quarter of fiscal 2023, the Company initiated a restructuring plan to better align strategic and financial objectives, optimize operations, and drive efficiencies for long-term growth and profitability, including a reduction in force affecting approximately 620 employees, or approximately 9% of the Company’s global workforce as of April 19, 2023. This included $53.2 million in severance benefits costs and related employer payroll taxes, and $3.5 million in charges related to the reduction of its leased facility space. The Company incurred $56.7 million in restructuring costs in the third quarter of fiscal 2023. For the year ended September 30, 2023, cash paid for severance benefits costs and related employer payroll taxes was $49.7 million. Remaining accrued expenses for the third quarter of fiscal 2023 restructuring plan was $3.5 million as of September 30, 2023. The Company does not expect to record any significant future charges related to the third quarter of fiscal 2023 restructuring plan. In the first quarters of fiscal 2023 and 2022, the Company initiated restructuring plans to match strategic and financial objectives and optimize resources for long term growth, including a reduction in force program. In the first quarter of fiscal 2023, the Company recorded a restructuring charge of $8.7 million. The Company did not record any significant future charges related to the first quarter of fiscal 2023 restructuring plan. In the first quarter of fiscal 2022, the Company recorded a restructuring charge of $7.9 million. The Company did not record any significant subsequent charges related to the first quarter of fiscal 2022 restructuring plan.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Sep. 30, 2023
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Employee Benefit Plans	Employee Benefit PlansThe Company has a 401(k) savings plan whereby eligible employees may voluntarily contribute a percentage of their compensation. The Company may, at its discretion, match a portion of the employees’ eligible contributions. Contributions by the Company to the plan during the years ended September 30, 2023, 2022, and 2021 were approximately $13.7 million, $14.0 million and $13.2 million, respectively. Contributions made by the Company vest over four years.

Segment Information

Segment Information	12 Months Ended
	Sep. 30, 2023
Segments, Geographical Areas [Abstract]
Segment Reporting Disclosure	Segment Information Revenues by Geographic Location and Other Information The Company does business in three main geographic regions: the Americas (primarily the United States); Europe, the Middle East, and Africa ("EMEA"); and the Asia Pacific region ("APAC"). The Company’s chief operating decision-maker reviews financial information presented on a consolidated basis accompanied by information about net product revenues and revenues by geographic region. The Company’s foreign offices conduct sales, marketing and support activities. Revenues are attributed by geographic location based on the location of the customer. The following presents revenues by geographic region (in thousands): Years Ended September 30, 2023 2022 2021 Americas: United States $ 1,487,416 $ 1,487,144 $ 1,365,625 Other 96,958 85,711 92,111 Total Americas 1,584,374 1,572,855 1,457,736 EMEA 741,598 634,759 667,219 Asia Pacific 487,197 488,231 478,461 $ 2,813,169 $ 2,695,845 $ 2,603,416 The Company continues to offer its products through a range of consumption models, from physical systems to software solutions and managed services. The following presents net product revenues by systems and software (in thousands): Years Ended September 30, 2023 2022 2021 Net product revenues Systems revenue $ 670,652 $ 651,902 $ 748,192 Software revenue 663,986 665,215 498,892 Total net product revenue $ 1,334,638 $ 1,317,117 $ 1,247,084 The following distributors of the Company's products accounted for more than 10% of total net revenue: Years Ended September 30, 2023 2022 2021 Ingram Micro, Inc. 15.6 % 20.0 % 19.2 % Synnex Corporation 15.0 % 13.4 % 11.1 % The following distributors of the Company's products accounted for more than 10% of total receivables: September 30, 2023 2022 Ingram Micro, Inc. — 12.9 % Synnex Corporation 16.0 % 12.6 % Carahsoft Technology Corporation 10.1 % 16.2 % The Company tracks assets by physical location. Long-lived assets consist of property and equipment, net, and are shown below (in thousands): September 30, 2023 2022 Americas: United States $ 125,736 $ 134,699 Other 2,592 1,773 Total Americas 128,328 136,472 EMEA 24,336 17,376 Asia Pacific 17,758 14,334 $ 170,422 $ 168,182

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Pay vs Performance Disclosure
Net income	$ 394,948	$ 322,160	$ 331,241

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Rule 10b5-1 and Non-Rule 10b5-1 Trading Arrangements During the three months ended September 30, 2023, certain of our officers and directors adopted or terminated Rule 10b5-1 trading arrangements as follows: On August 11, 2023, Frank Pelzer, EVP, Chief Financial Officer, adopted a written plan intended to satisfy the affirmative defense of Rule 10b5-1(c) that is designed to be in effect until October 25, 2024 with respect to the sale of 11,300 Company shares.
Rule 10b5-1 Arrangement Adopted	true
Rule 10b5-1 Arrangement Terminated	false
Frank Pelzer [Member]
Trading Arrangements, by Individual
Name	Frank Pelzer
Title	EVP, Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 11, 2023
Aggregate Available	11,300

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Accounting Principles	Accounting Principles The Company’s consolidated financial statements and accompanying notes are prepared on the accrual basis of accounting in accordance with generally accepted accounting principles in the United States of America ("GAAP").
Principles Of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use Of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Examples of estimates and assumptions include: revenue recognition, identifying and evaluating the performance obligations of contracts with non-standard terms, and the allocation of purchase consideration based on the relative fair value standalone sales price of these performance obligations; business combinations, including the determination of fair value for acquired developed technology assets and the evaluation and selection of significant assumptions such as revenue growth rate and technology migration curve; and the incremental borrowing rate for measuring lease obligations. Actual results may differ materially from management's estimates and assumptions.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted CashThe Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The Company invests its cash and cash equivalents in deposits with four major financial institutions, which, at times, exceed federally insured limits. The Company has not experienced any losses on its cash and cash equivalents. Amounts included in restricted cash represent those for which the Company's use is restricted by a contractual agreement.
Investments	Investments The Company classifies its debt investments as available-for-sale. Debt investments, consisting of money market funds, corporate and municipal bonds and notes, the United States government and agency securities are reported at fair value with the related unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in shareholders’ equity. Realized gains and losses, credit allowances and impairments due to credit losses are included in other income (expense) in the Company’s consolidated income statements. Debt investments with maturities of less than one year or where management’s intent is to use the investments to fund current operations are classified as short-term investments. Debt investments with maturities of greater than one year are classified as long-term investments. As an approximation to fair value, equity investments are measured using net asset value (“NAV”) and are classified as long-term investments. Unrealized and realized gains and losses are recorded in other income (expense) in the Company's consolidated income statements.
Accounts Receivable	Accounts Receivable Trade accounts receivable are recorded at the invoiced amount, net of allowances for credit losses for any potential uncollectible amounts. The allowance for credit losses is based on the assessment of the collectability of accounts. Management regularly reviews the adequacy of the allowance for credit losses on a collective basis by considering the age of each outstanding invoice, each customer’s expected ability to pay and collection history, current market conditions, and reasonable and supportable forecasts of future economic conditions to determine whether the allowance is appropriate. Accounts receivable deemed uncollectible are charged against the allowance for credit losses when identified. For fiscal years ended September 30, 2023 and 2022, the allowance for credit losses was not material.
Unbilled Receivables	Unbilled Receivables Unbilled receivables represent amounts related to the Company's unconditional right to consideration associated with contracts with customers that have not yet been billed. Unbilled receivables are converted to accounts receivable at the point in time when the Company has the contractual right to invoice its customers. As of September 30, 2023, unbilled receivables that are expected to be reclassified to accounts receivable within the next 12 months are included in other current assets, with those expected to be transferred to accounts receivables in more than 12 months included in other assets.
Concentration Of Credit Risk	Concentration of Credit Risk The Company extends credit to customers and is therefore subject to credit risk. The Company performs initial and ongoing credit evaluations of its customers’ financial condition and does not require collateral. An allowance for credit losses is recorded for any potential uncollectible amount. Estimates are used in determining the allowance for credit losses in accordance with the Accounts Receivable policy. See Note 15 - Segment Information, for disaggregated accounts receivable by significant customer. The Company maintains its cash and investment balances with high credit quality financial institutions.
Fair Value Of Financial Instruments	Fair Value of Financial Instruments Short-term and long-term investments are recorded at fair value as the underlying securities are classified as available-for-sale with any unrealized gains or losses being recorded to other comprehensive income (or loss). The fair value for securities held is determined using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency.
Inventories	Inventories The Company outsources the manufacturing of its pre-configured hardware platforms to contract manufacturers, who assemble each product to the Company’s specifications. As protection against component shortages and to provide replacement parts for its service teams, the Company also stocks limited supplies of certain key product components. The Company reduces inventory to net realizable value based on excess and obsolete inventories determined primarily by historical usage and forecasted demand. Inventories consist of hardware and related component parts and are recorded at the lower of cost and net realizable value (as determined by the first-in, first-out method).
Property And Equipment	Property and Equipment Property and equipment are stated at net book value. Depreciation of property and equipment is provided using the straight-line method over the estimated useful lives of the assets, ranging from two Property and equipment consist of the following (in thousands): September 30, 2023 2022 Computer equipment $ 189,555 $ 168,204 Software 78,184 86,036 Office furniture and equipment 44,525 41,619 Leasehold improvements 185,225 173,689 497,489 469,548 Accumulated depreciation and amortization (327,067) (301,366) $ 170,422 $ 168,182
Business Combinations	Business Combinations The Company’s business combinations are accounted for under the acquisition method. Management allocates the fair value of purchase consideration to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition date. The excess of the fair value of purchase consideration over the fair values of these identifiable assets and liabilities is recorded as goodwill. Such valuations require management to make significant estimates and assumptions, especially with respect to intangible assets.
Goodwill	Goodwill Goodwill represents the excess purchase price over the estimated fair value of net assets acquired as of the acquisition date. The Company tests goodwill for impairment on an annual basis and between annual tests when impairment indicators are identified, and goodwill is written down when impaired. For its annual goodwill impairment test in all periods to date, the Company has operated under one reporting unit and the fair value of its reporting unit has been determined by the Company’s enterprise value. The Company performs its annual goodwill impairment test during the second fiscal quarter. For its annual impairment test performed in the second quarter of fiscal 2023, the Company completed a quantitative assessment and determined that there was no impairment of goodwill. The Company also considered potential impairment indicators of goodwill at September 30, 2023 and noted no indicators of impairment.
Intangible Assets	Intangible AssetsIntangible assets with finite lives consist of acquired developed technology, customer relationships, patents and trademarks, trade names, and non-compete covenants acquired through business combinations or asset acquisitions. Intangible assets acquired through business combinations are recorded at their respective estimated fair values upon acquisition close. Other intangible assets acquired through asset acquisitions are recorded at their respective cost. The Company determines the estimated useful lives for acquired intangible assets based on the expected future cash flows associated with the respective asset. The Company's intangible assets with finite lives are amortized using the straight-line method over their estimated useful lives, ranging from four
Software Development Costs	Software Development Costs The authoritative guidance requires certain internal software development costs related to software to be sold to be capitalized upon the establishment of technological feasibility. Capitalized software development costs are amortized over the remaining estimated economic life of the product. The Company's software development costs incurred subsequent to achieving technological feasibility have not been significant and, as a result, all software development costs have been expensed as research and development activities as incurred.
Internal-Use Software	Internal-Use Software The Company capitalizes costs incurred during the application development stage associated with the development of internal-use software systems. The capitalized costs are then amortized over the estimated useful life of the software, which is generally three
Impairment Of Long-Lived Assets	Impairment of Long-Lived AssetsThe Company assesses the impairment of long-lived assets whenever events or changes in business circumstances indicate that the carrying amount of an asset may not be recoverable. When such events occur, management determines whether there has been impairment by comparing the anticipated undiscounted net future cash flows to the related asset’s carrying value. If impairment exists, the asset is written down to its estimated fair value.
Revenue Recognition	Revenue Recognition The Company sells products through distributors, resellers, and directly to end users. Revenue related to the Company's contracts with customers is recognized by following a five-step process: • Identify the contract(s) with a customer. Evidence of a contract generally consists of a purchase order issued pursuant to the terms and conditions of a distributor, reseller or end user agreement. • Identify the performance obligations in the contract. Performance obligations are identified in the Company's contracts and include hardware, hardware-based software, software-only solutions, cloud-based subscription services as well as a broad range of service performance obligations including consulting, training, installation and maintenance. • Determine the transaction price. The purchase price stated in an agreed upon purchase order is generally representative of the transaction price. The Company offers several programs in which customers are eligible for certain levels of rebates if certain conditions are met. When determining the transaction price, the Company considers the effects of any variable consideration. • Allocate the transaction price to the performance obligations in the contract. The transaction price in a contract is allocated based upon the relative standalone selling price of each distinct performance obligation identified in the contract. • Recognize revenue when (or as) the entity satisfies a performance obligation. The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring control of promised products and services to a customer. Revenue is recognized net of any taxes collected, which are subsequently remitted to governmental authorities. Shipping and handling fees charged to the Company’s customers are recognized as product revenue in the period shipped and the related costs for providing these services are recorded as a cost of sale. The following is a description of the principal activities from which the Company generates revenue: Product Revenue from the sale of the Company's hardware and perpetual software products is generally recognized at a point in time when the product has been fulfilled and the customer is obligated to pay for the product. The Company also offers several products by subscription, either through term-based license agreements or as SaaS offerings. Revenue for term-based license agreements is recognized at a point in time, when the Company delivers the software license to the customer and the subscription term has commenced. For the Company's SaaS offerings, revenue is recognized ratably as the services are provided. Hardware, including the software run on those devices is considered systems revenue. Perpetual or subscription software offerings that are, or have the ability to be deployed on a standalone basis, along with the Company's SaaS offerings are considered software revenue. When rights of return are present and the Company cannot estimate returns, revenue is recognized when such rights of return lapse. Payment terms to customers are generally net 30 days to net 60 days. Global Services Revenues for post-contract customer support ("PCS") are recognized on a straight-line basis over the service contract term. PCS includes a limited period of telephone support, updates, repair or replacement of any failed product or component that fails during the term of the agreement, bug fixes and rights to upgrades, when and if available. Consulting services are customarily billed at fixed hourly rates, plus out-of-pocket expenses, and revenues are recognized as the consulting is delivered. Similarly, training revenue is recognized as the training is completed. Contract Acquisition Costs Sales commissions earned by the Company's sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for initial service contracts and subscription offerings are deferred and then amortized as an expense on a straight-line basis over the period of benefit, which management has determined to be 4.5 years for initial service and 3 to 5 years for subscription offerings. Flexible Consumption Program The Company enters into certain contracts with customers, including flexible consumption programs and multi-year subscriptions, with non-standard terms and conditions. Management assesses contractual terms in these agreements to identify and evaluate performance obligations. Management allocates consideration to each performance obligation based on relative fair value using standalone selling price and recognizes associated revenue as control is transferred to the customer.
Guarantees And Product Warranties	Guarantees and Product Warranties In the normal course of business to facilitate sales of its products, the Company indemnifies other parties, including customers, resellers, lessors, and parties to other transactions with the Company, with respect to certain matters. The Company has agreed to hold the other party harmless against losses arising from a breach of representations or covenants, or out of intellectual property infringement or other claims made against certain parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. The Company has entered into indemnification agreements with its officers and directors, and the Company’s bylaws contain similar indemnification obligations to the Company’s agents. It is not possible to determine the maximum potential amount under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement.
Research And Development	Research and Development Research and development expenses consist of salaries and related benefits of product development personnel, prototype materials and expenses related to the development of new and improved products, and an allocation of facilities, depreciation and amortization expense. Research and development expenses are reflected in the income statements as incurred.
Advertising	Advertising Advertising costs are expensed as incurred. The Company incurred $8.9 million, $15.4 million and $10.0 million in advertising costs during the fiscal years 2023, 2022 and 2021, respectively.
Income Taxes	Income Taxes Deferred income tax assets and liabilities are determined based upon differences between the financial statement and income tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The realization of deferred tax assets is based on historical tax positions and estimates of future taxable income. A valuation allowance is recorded when it is more-likely-than-not that some of the deferred tax assets will not be realized. The Company assesses whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the financial statements. The Company may recognize the tax benefit from an uncertain tax position only if it is more-likely-than-not that the tax position will be sustained on examination by the taxing authorities, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The tax benefits to be recognized in the financial statements from such a position is measured as the largest amount of benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. The Company adjusts these liabilities based on a variety of factors, including the evaluation of information not previously available. These adjustments are reflected as increases or decreases to income tax expense in the period in which new information is available.
Foreign Currency	Foreign Currency The functional currency for the Company’s foreign subsidiaries is either the U.S. dollar or the local currency depending on the assessment of management. An entity’s functional currency is determined by the currency of the economic environment in which the majority of cash is generated and expended by the entity. The financial statements of all majority-owned subsidiaries and related entities, with a functional currency other than the U.S. dollar, have been translated into U.S. dollars. All assets and liabilities of the respective entities are translated at year-end exchange rates and all revenues and expenses are translated at average rates during the respective period. Translation adjustments are reported as other comprehensive income (loss) in the consolidated statements of comprehensive income. Foreign currency transaction gains and losses are a result of the effect of exchange rate changes on transactions denominated in currencies other than the functional currency, including U.S. dollars. Gains and losses on those foreign currency transactions are included in determining net income or loss for the period of exchange and are recorded in other income, net. The net effect of foreign currency gains and losses was not material during the fiscal years ended September 30, 2023, 2022 and 2021.
Segments	Segments Operating segments are defined as components of an enterprise for which separate financial information is available and evaluated regularly by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources and in assessing performance. Management has determined that the Company is organized as, and operates in, one reportable operating segment.
Stock-Based Compensation	Stock-based Compensation The Company issues incentive awards to its employees through stock-based compensation consisting of restricted stock units ("RSUs"). RSUs are payable in shares of the Company’s common stock as the periodic vesting requirements are satisfied, generally over one The Company offers an Employee Stock Purchase Plan ("ESPP") that permits eligible employees to purchase shares of the Company’s common stock at a discount. In determining the fair value of shares issued under the ESPP, the Company uses the Black-Scholes option pricing model. The assumptions within the option pricing model are based on management’s best estimates at that time, which impact the fair value of the ESPP option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the life of the ESPP option. The Company has also issued stock options as replacement awards, most notably for those assumed as part of business combinations. The Company used the Black-Scholes option pricing model to determine the fair value of the stock option replacement awards. The assumptions within the option pricing model are based on management’s best estimates at that time, which impact the fair value of the option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the term of the option. The Company accounts for stock-based compensation using the straight-line attribution method for recognizing compensation expense. The Company recognizes compensation expense for only the portion of stock-based awards that are expected to vest. Therefore, the Company applies estimated forfeiture rates that are derived from historical employee termination behavior. Based on historical differences with forfeitures of stock-based awards granted to the Company’s executive officers and Board of Directors versus grants awarded to all other employees, the Company has developed separate forfeiture expectations for these two groups. The Company issues incentive awards to certain current executive officers as part of its annual equity awards program. A portion of the aggregate number of RSUs issued to executive officers vest in equal quarterly increments, and a portion is subject to the Company achieving specified performance goals. In fiscal 2018, the Company's Talent and Compensation Committee adopted a set of metrics for the performance stock awards, including (1) 50% of the annual performance stock grant is based on achieving certain annual revenue; (2) 25% of the annual performance stock grant is based on achieving an increase annual software revenue compared to the prior year; and (3) 25% of the annual performance stock grant is based on relative total shareholder return ("TSR") benchmarked to the S&P 500 index. In fiscal 2023, the Company's Talent and Compensation Committee amended the metrics for the performance stock awards to replace software revenue with earnings per share. In each case, no vesting or payment with respect to a performance goal shall occur unless a minimum threshold is met for the applicable goal. Vesting and payment with respect to the performance goal is linear above the threshold of the applicable goal and is capped at achievement of 200% above target. The Company recognizes compensation costs for awards with performance conditions and market conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award and, for awards with performance conditions, when it concludes it is probable that the performance condition will be achieved. The Company reassesses the probability of vesting at each balance sheet date and adjusts compensation costs based on the probability assessment.
Comprehensive Income	Comprehensive Income Comprehensive income includes certain changes in equity that are excluded from net income. Specifically, unrealized gains or losses on securities and foreign currency translation adjustments. These changes are included in accumulated other comprehensive income or loss.
Recent Accounting Pronouncements	Recently Adopted Accounting Standards There have been no material changes in recently issued or adopted accounting standards from those disclosed in the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2022.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): September 30, 2023 2022 Finished goods $ 11,699 $ 10,164 Raw materials 24,175 58,201 $ 35,874 $ 68,365
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share data): Years Ended September 30, 2023 2022 2021 Numerator Net income $ 394,948 $ 322,160 $ 331,241 Denominator Weighted average shares outstanding — basic 59,909 60,274 60,707 Dilutive effect of common shares from stock options and restricted stock units 361 823 1,350 Weighted average shares outstanding — diluted 60,270 61,097 62,057 Basic net income per share $ 6.59 $ 5.34 $ 5.46 Diluted net income per share $ 6.55 $ 5.27 $ 5.34

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Sep. 30, 2023
Revenue from Contracts with Customers [Abstract]
Capitalized Contract Cost	The table below shows significant movements in capitalized contract acquisition costs (current and noncurrent) for the years ended September 30, 2023, 2022, and 2021 (in thousands): 2023 2022 2021 Balance, beginning of year $ 77,220 $ 77,836 $ 70,396 Additional capitalized contract acquisition costs 26,960 37,897 41,719 Amortization of capitalized contract acquisition costs (37,712) (38,513) (34,279) Balance, end of year $ 66,468 $ 77,220 $ 77,836
Contract with Customer, Asset and Liability	The table below shows significant movements in the deferred revenue balances (current and noncurrent) for the years ended September 30, 2023, 2022, and 2021 (in thousands): 2023 2022 2021 Balance, beginning of year $ 1,691,580 $ 1,489,842 $ 1,272,632 Amounts added but not recognized as revenues 1,162,698 1,167,143 1,122,081 Deferred revenue acquired through acquisition of businesses 1,800 10,591 779 Revenues recognized related to the opening balance of deferred revenue (1,080,957) (975,996) (905,650) Balance, end of year $ 1,775,121 $ 1,691,580 $ 1,489,842

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Sep. 30, 2023
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The allocated purchase consideration to assets acquired and liabilities assumed based on preliminary estimated fair values is presented in the following table (in thousands): Estimated Useful Life Assets acquired Deferred tax assets $ 14,041 Other net tangible assets acquired, at fair value 5,481 Cash, cash equivalents, and restricted cash 911 Identifiable intangible assets: Developed technology 11,400 5 years Customer relationships 4,400 5 years Goodwill 43,282 Total assets acquired $ 79,515 Liabilities assumed Deferred revenue $ (10,591) Total liabilities assumed $ (10,591) Net assets acquired $ 68,924 The allocated purchase consideration to assets acquired and liabilities assumed based on preliminary estimated fair values is presented in the following table (in thousands): Estimated Useful Life Assets acquired Cash, cash equivalents, and restricted cash $ 14,012 Other tangible assets acquired, at fair value 7,499 Identifiable intangible assets: Developed technology 59,500 7 years Customer relationships 500 1 year Goodwill 350,863 Total assets acquired 432,374 Liabilities assumed (5,233) Net assets acquired $ 427,141

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule Of Financial Assets Measured At Fair Value on A Recurring Basis	The Company's financial assets measured at fair value on a recurring basis subject to the disclosure requirements at September 30, 2023 and 2022, were as follows (in thousands): Gross Unrealized Classification on Balance Sheet As of September 30, 2023 Fair Value Level Cost or Amortized Cost Gains Losses Aggregate Cash and Cash Equivalents Short-Term Investments Long-Term Investments Changes in fair value recorded in other comprehensive income Money Market Funds Level 1 $ 392,592 $ — $ — $ 392,592 $ 392,592 $ — $ — Corporate bonds and notes Level 2 4,412 — (88) 4,324 — 4,324 — Municipal bonds and notes Level 2 1,108 — (9) 1,099 — 1,099 — U.S. government securities Level 2 — — — — — — — U.S. government agency securities Level 2 740 — (3) 737 — 737 — Total debt investments $ 398,852 $ — $ (100) $ 398,752 $ 392,592 $ 6,160 $ — Changes in fair value recorded in other net income (expense) Equity investments * $ 5,068 $ — $ — $ 5,068 Total equity investments 5,068 — — 5,068 Total investments $ 403,820 $ 392,592 $ 6,160 $ 5,068 * The fair value of this equity investment is measured at net asset value (NAV) which approximates fair value and is not classified within the fair value hierarchy . Gross Unrealized Classification on Balance Sheet As of September 30, 2022 Fair Value Level Cost or Amortized Cost Gains Losses Aggregate Cash and Cash Equivalents Short-Term Investments Long-Term Investments Changes in fair value recorded in other comprehensive income Money Market Funds Level 1 $ 276,294 $ — $ — $ 276,294 $ 276,294 $ — $ — Corporate bonds and notes Level 2 50,828 — (950) 49,878 912 44,356 4,610 Municipal bonds and notes Level 2 5,018 — (102) 4,916 — 3,812 1,104 U.S. government securities Level 2 84,734 — (660) 84,074 10,120 73,954 — U.S. government agency securities Level 2 5,825 — (75) 5,750 606 4,432 712 Total debt investments $ 422,699 $ — $ (1,787) $ 420,912 $ 287,932 $ 126,554 $ 6,426 Changes in fair value recorded in other net income (expense) Equity investments * $ 3,118 $ — $ — $ 3,118 Total equity investments 3,118 — — 3,118 Total investments $ 424,030 $ 287,932 $ 126,554 $ 9,544
Impairment Charges	Impairment charges were allocated to the following income statement line items for the years ended September 30, 2023, 2022, and 2021 (in thousands): Years Ended September 30, 2023 2022 2021 Cost of net product revenue $ — $ — $ 2,865 Cost of net service revenue — — 3,492 Sales and marketing — 6,175 11,515 Research and development — — 12,974 General and administrative — — 9,852 Restructuring charges 3,455 — — Total impairment charges $ 3,455 $ 6,175 $ 40,698

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Sep. 30, 2023
Balance Sheet Details [Abstract]
Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of the Company’s cash and cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash shown in the Company’s consolidated statements of cash flows for the periods presented (in thousands): September 30, 2023 2022 Cash and cash equivalents $ 797,163 $ 758,012 Restricted cash included in other assets, net 3,672 4,195 Total cash, cash equivalents and restricted cash $ 800,835 $ 762,207
Inventories	Inventories consist of the following (in thousands): September 30, 2023 2022 Finished goods $ 11,699 $ 10,164 Raw materials 24,175 58,201 $ 35,874 $ 68,365
Other Current Assets	Other current assets consist of the following (in thousands): September 30, 2023 2022 Unbilled receivables $ 374,113 $ 319,707 Prepaid expenses 84,506 57,340 Capitalized contract acquisition costs 31,206 34,658 Other 1 64,919 77,609 $ 554,744 $ 489,314 (1) As of September 30, 2023 and 2022, includes a deposit of $36.2 million and $57.0 million, respectively, used to support the working capital needs of the Company’s primary contract manufacturer's procurement of components used in the manufacturing of system hardware.
Property, Plant and Equipment	Property and Equipment Property and equipment are stated at net book value. Depreciation of property and equipment is provided using the straight-line method over the estimated useful lives of the assets, ranging from two Property and equipment consist of the following (in thousands): September 30, 2023 2022 Computer equipment $ 189,555 $ 168,204 Software 78,184 86,036 Office furniture and equipment 44,525 41,619 Leasehold improvements 185,225 173,689 497,489 469,548 Accumulated depreciation and amortization (327,067) (301,366) $ 170,422 $ 168,182
Goodwill	Changes in the carrying amount of goodwill during fiscal years 2023 and 2022 are summarized as follows (in thousands): Balance, September 30, 2021 $ 2,216,553 Acquisition of Threat Stack, Inc. 43,956 Other (1,227) Balance, September 30, 2022 2,259,282 Other business acquisitions 29,396 Balance, September 30, 2023 $ 2,288,678
Other Assets	Other assets consist of the following (in thousands): September 30, 2023 2022 Intangible assets $ 150,969 $ 200,288 Unbilled receivables 202,838 224,780 Capitalized contract acquisition costs 35,263 42,561 Other 55,543 48,493 $ 444,613 $ 516,122
Intangible Assets	Intangible assets are included in other assets on the consolidated balance sheets and consist of the following (in thousands): September 30, 2023 September 30, 2022 Gross Accumulated Net Carrying Gross Accumulated Net Carrying Developed technology $ 319,368 $ (190,135) $ 129,233 $ 319,436 $ (151,332) $ 168,104 Customer relationships 45,642 (33,298) 12,344 46,142 (25,630) 20,512 Patents and trademarks 13,699 (9,658) 4,041 23,504 (19,255) 4,249 Trade names 15,473 (10,122) 5,351 24,973 (17,550) 7,423 Non-compete covenants 1,960 (1,960) — 2,260 (2,260) — $ 396,142 $ (245,173) $ 150,969 $ 416,315 $ (216,027) $ 200,288
Estimated Amortization Expense For Intangible Assets	For intangible assets held as of September 30, 2023, amortization expense for the five succeeding fiscal years is as follows (in thousands): 2024 $ 50,914 2025 39,477 2026 34,723 2027 16,541 2028 4,106 $ 145,761
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): September 30, 2023 2022 Payroll and benefits $ 152,898 $ 165,437 Operating lease liabilities, current 41,421 42,523 Income and other tax accruals 34,504 41,217 Other 54,067 60,642 $ 282,890 $ 309,819
Other Long-term Liabilities	Other long-term liabilities consist of the following (in thousands): September 30, 2023 2022 Income taxes payable $ 73,751 $ 59,553 Other 8,822 8,157 $ 82,573 $ 67,710

Leases (Tables)

Leases (Tables)	12 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Lease, Cost	The components of the Company's operating lease expenses for the years ended September 30, 2023, 2022, and 2021 were as follows (in thousands): Fiscal year ended September 30, 2023 2022 2021 Operating lease expense $ 47,036 $ 47,302 $ 47,993 Short-term lease expense 2,986 2,465 2,953 Variable lease expense 23,139 23,209 25,200 Total lease expense $ 73,161 $ 72,976 $ 76,146
Assets And Liabilities Lessee	Supplemental balance sheet information related to the Company's operating leases was as follows (in thousands, except lease term and discount rate): September 30, 2023 2022 Operating lease right-of-use assets, net $ 195,471 $ 227,475 Operating lease liabilities, current 1 41,421 42,523 Operating lease liabilities, long-term 239,565 272,376 Total operating lease liabilities $ 280,986 $ 314,899 Weighted average remaining lease term (in years) 8.6 9.2 Weighted average discount rate 2.77 % 2.66 % (1) Current portion of operating lease liabilities is included in accrued liabilities on the Company's consolidated balance sheets.
Lessee, Operating Lease, Liability, Maturity	As of September 30, 2023, the future operating leases payments for each of the next five years and thereafter is as follows (in thousands): Fiscal Years Ending September 30: Operating Lease 2024 $ 48,709 2025 41,095 2026 31,559 2027 30,394 2028 28,340 Thereafter 138,797 Total lease payments 318,894 Less: imputed interest (37,908) Total lease liabilities $ 280,986

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Components Of Income Before Income Taxes	The United States and international components of income before income taxes are as follows (in thousands): Years Ended September 30, 2023 2022 2021 United States $ 268,314 $ 217,323 $ 189,398 International 217,674 168,070 197,539 $ 485,988 $ 385,393 $ 386,937
Schedule Of Provision For Income Taxes (Benefit)	The provision for income taxes consists of the following (in thousands): Years Ended September 30, 2023 2022 2021 Current U.S. federal $ 115,170 $ 35,259 $ 53,107 State 18,359 14,592 16,686 Foreign 66,053 54,079 62,832 Total 199,582 103,930 132,625 Deferred U.S. federal (89,280) (28,721) (61,739) State (18,576) (11,332) (15,294) Foreign (686) (644) 104 Total (108,542) (40,697) (76,929) $ 91,040 $ 63,233 $ 55,696
Schedule Of Effective Tax Rate Differs From The U.S. Federal Statutory Rate	The effective tax rate differs from the U.S. federal statutory rate as follows (in thousands): Years Ended September 30, 2023 2022 2021 Income tax provision at statutory rate $ 102,058 $ 80,933 $ 81,257 State taxes, net of federal benefit 6,806 6,012 5,118 Tax impact of foreign operations (20,230) (21,435) (26,881) Research and development and other credits (19,198) (18,917) (18,055) Stock-based and other compensation 20,145 15,070 12,740 Other 1,459 1,570 1,517 $ 91,040 $ 63,233 $ 55,696
Schedule Of Tax Effects To Deferred Tax Assets And Liabilities	The tax effects of the temporary differences that give rise to the deferred tax assets and liabilities are as follows (in thousands): Years Ended September 30, 2023 2022 Deferred tax assets Net operating loss carry-forwards $ 40,201 $ 42,849 Capitalized research and development costs 267,744 158,206 Accrued compensation and benefits 11,995 14,068 Stock-based compensation 8,875 10,389 Deferred revenue 42,544 32,244 Lease liabilities 62,405 67,520 Other accruals and reserves 22,723 18,797 Tax credit carryforwards 23,883 28,858 Depreciation 531 505 480,901 373,436 Valuation allowance (43,942) (46,136) 436,959 327,300 Deferred tax liabilities Purchased intangibles (55,519) (57,350) Depreciation (28,113) (22,278) Deferred costs (11,031) (12,987) Lease assets (41,709) (45,948) Other accruals and reserves (9,916) (8,153) (146,288) (146,716) Net deferred tax assets $ 290,671 $ 180,584
Schedule Of Reconciliation Of Beginning And Ending Amount Of Unrecognized Tax Benefits	The following table provides a reconciliation of the beginning and ending amount of unrecognized tax benefits in fiscal years 2023, 2022 and 2021 (in thousands): 2023 2022 2021 Balance, beginning of period $ 66,840 $ 70,814 $ 51,767 Gross increases related to prior period tax positions 4,270 4,816 14,867 Gross decreases related to prior period tax positions (70) (10,538) — Gross increases related to current period tax positions 9,224 10,203 12,595 Decreases relating to settlements with tax authorities (300) — (321) Reductions due to lapses of statute of limitations (797) (8,455) (8,094) Balance, end of period $ 79,167 $ 66,840 $ 70,814

Equity (Tables)

Equity (Tables)	12 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Common Stock Repurchased and Retired	The following table summarizes the Company's repurchases and retirements of its common stock under its Stock Repurchase Program, including the ASR (in thousands, except per share data): Years Ended September 30, 2023 2022 2021 Shares repurchased 2,454 2,611 2,501 Average price per share $ 142.62 $ 191.47 $ 199.90 Amount repurchased $ 350,049 $ 500,023 $ 500,000

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Schedule Of Assumptions In Determining The Fair Value Of Shares Issued Under The Employee Stock Purchase Plan	In determining the fair value of the right to purchase under the Employee Stock Purchase Plan, the Company uses the Black-Scholes option pricing model that employs the following key assumptions: Employee Stock Purchase Plan 2023 2022 2021 Risk-free interest rate 3.18% - 4.90% 0.05% - 0.62% 0.07% - 0.13% Expected dividend — — — Expected term 0.5 years 0.5 years 0.5 years Expected volatility 33.02% - 38.15% 26.34% - 31.57% 29.67% - 37.22%
Schedule Of Summary Of Restricted Stock Unit Activity	A summary of restricted stock unit activity under the Plan is as follows: Performance Stock Units Restricted Stock Units Outstanding Weighted Outstanding Weighted Balance, September 30, 2022 208,116 $ 169.99 1,137,619 $ 184.59 Units granted 131,491 145.02 1,448,427 145.10 Units vested (92,677) 144.69 (1,113,259) 147.10 Units cancelled (47,012) 171.07 (247,401) 162.80 Balance, September 30, 2023 199,918 $ 159.37 1,225,386 $ 156.89
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	In determining the fair value of the portion of the performance awards based on Total Shareholder Return, the Company uses a Monte Carlo simulation model that employs the following key assumptions: Expected Volatility Fair Value Expected Term Risk-Free Index Expected Grant Date per Share (in years) Interest Rate F5 Members Dividend November 1, 2022 Tranche 1 $ 157.36 0.91 4.66 % 37.17 % 35.56 % — Tranche 2 $ 173.68 1.91 4.51 % 31.84 % 31.74 % — Tranche 3 $ 194.41 2.91 4.44 % 35.50 % 40.59 % —
Schedule of Nonvested Restricted Stock Units Activity	As of September 30, 2023, the following annual equity grants for executive officers or a portion thereof are outstanding: Grant Date RSUs Granted Vesting Schedule Vesting Period Date Fully Vested November 1, 2022 240,808 Quarterly, Annually 1,2 3 years November 1, 2025 November 1, 2021 160,384 Quarterly, Annually 1,2 3 years November 1, 2024 November 2, 2020 257,568 Quarterly, Annually 1 3 years November 1, 2023 November 1, 2019 228,616 Quarterly, Annually 1 3 years November 1, 2022 (1) 50% of the annual equity grant vests in equal quarterly increments and 50% is subject to the Company achieving specified annual performance goals. (2) For the Company's Chief Executive Officer, 40% of the annual equity grant vests in equal quarterly increments and 60% is subject to the Company achieving specified annual performance goals.
Schedule Of Stock Option Activity	A summary of stock option activity under all of the Company’s plans is as follows: Options Outstanding Number of Weighted Balance, September 30, 2022 164,796 $ 33.34 Options granted 2,051 4.55 Options exercised (56,516) 26.38 Options cancelled (4,463) 61.35 Balance, September 30, 2023 105,868 $ 35.31
Schedule Of Outstanding Stock Options Currently Exercisable, Vested And Expected To Vest	A summary of options outstanding that are exercisable and that have vested and are expected to vest as of September 30, 2023 is as follows: Number of Weighted Weighted Aggregate (In thousands) Stock options outstanding 105,868 5.62 $ 35.31 $ 13,321 Exercisable 99,067 5.54 $ 35.47 $ 12,449 Vested and expected to vest 105,561 5.61 $ 35.36 $ 13,277 (1) Aggregate intrinsic value represents the difference between the fair value of the Company’s common stock underlying these options at September 30, 2023 and the related exercise prices.
Schedule Of Equity Based Awards (Including Stock Options And Restricted Stock Units)	As of September 30, 2023, equity based awards (including stock options and restricted stock units) are available for future issuance as follows: Awards Balance, September 30, 2022 2,072,778 Granted (1,629,873) Cancelled 349,715 Additional shares reserved (terminated), net 4,504,183 Balance, September 30, 2023 5,296,803

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Sep. 30, 2023
Net Income Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share data): Years Ended September 30, 2023 2022 2021 Numerator Net income $ 394,948 $ 322,160 $ 331,241 Denominator Weighted average shares outstanding — basic 59,909 60,274 60,707 Dilutive effect of common shares from stock options and restricted stock units 361 823 1,350 Weighted average shares outstanding — diluted 60,270 61,097 62,057 Basic net income per share $ 6.59 $ 5.34 $ 5.46 Diluted net income per share $ 6.55 $ 5.27 $ 5.34

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Sep. 30, 2023
Segments, Geographical Areas [Abstract]
Schedule Of Revenues By Geographic Region	The following presents revenues by geographic region (in thousands): Years Ended September 30, 2023 2022 2021 Americas: United States $ 1,487,416 $ 1,487,144 $ 1,365,625 Other 96,958 85,711 92,111 Total Americas 1,584,374 1,572,855 1,457,736 EMEA 741,598 634,759 667,219 Asia Pacific 487,197 488,231 478,461 $ 2,813,169 $ 2,695,845 $ 2,603,416
Schedule of Revenues by Systems and Software	The following presents net product revenues by systems and software (in thousands): Years Ended September 30, 2023 2022 2021 Net product revenues Systems revenue $ 670,652 $ 651,902 $ 748,192 Software revenue 663,986 665,215 498,892 Total net product revenue $ 1,334,638 $ 1,317,117 $ 1,247,084
Schedule of Revenue by Major Customers by Reporting Segments	The following distributors of the Company's products accounted for more than 10% of total net revenue: Years Ended September 30, 2023 2022 2021 Ingram Micro, Inc. 15.6 % 20.0 % 19.2 % Synnex Corporation 15.0 % 13.4 % 11.1 %
Schedule of Receivables by Major Customers by Reporting Segments	The following distributors of the Company's products accounted for more than 10% of total receivables: September 30, 2023 2022 Ingram Micro, Inc. — 12.9 % Synnex Corporation 16.0 % 12.6 % Carahsoft Technology Corporation 10.1 % 16.2 %
Long-lived Assets by Geographic Areas [Table Text Block]	The Company tracks assets by physical location. Long-lived assets consist of property and equipment, net, and are shown below (in thousands): September 30, 2023 2022 Americas: United States $ 125,736 $ 134,699 Other 2,592 1,773 Total Americas 128,328 136,472 EMEA 24,336 17,376 Asia Pacific 17,758 14,334 $ 170,422 $ 168,182

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Segment Reporting [Abstract]
Number of Reportable Segments | segment	1
Advertising
Advertising Expense | $	$ 8.9	$ 15.4	$ 10
Restricted Stock Units (RSUs) [Member]
Restricted Stock Award
Award vesting period	2 years	2 years	2 years
Restricted Stock Units (RSUs) [Member] | Annual Equity Program [Member]
Restricted Stock Award
Percentage Of Annual Performance Stock Grant Based On Achieving Annual Revenue Goal	50%
Percentage Of Annual Performance Stock Grant Based On Achieving Annual Increase in Stand-alone Software Goal		25%
Percentage Of Annual Performance Stock Grant Based On Achieving Earnings Per Share Goal	25%
Percentage Of Annual Performance Stock Grant Based On Achieving Relative Total Shareholder Return Benchmarked to the S&P 500 Index Goal	25%
Percentage Of Over-Achievement To Which Annual Performance Based Vesting Cannot Exceed	200%
Maintenance [Member]
Revenue Recognition
Capitalized Contract Cost, Amortization Period	4 years 6 months
Hardware [Member]
Guarantees and Product Warranties
Standard Product Warranty Description	one year
Minimum
Property, Plant and Equipment [Abstract]
Property and equipment, useful life	2 years
Segment Reporting [Abstract]
Finite-Lived Intangible Asset, Useful Life	4 years
Revenue Recognition
Revenue, Performance Obligation, Description of Payment Terms	30
Restricted Stock Award
Award vesting period	1 year
Minimum | Subscription and Circulation [Member]
Revenue Recognition
Capitalized Contract Cost, Amortization Period	3 years
Minimum | Software and Software Development Costs [Member]
Segment Reporting [Abstract]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum
Property, Plant and Equipment [Abstract]
Property and equipment, useful life	5 years
Segment Reporting [Abstract]
Finite-Lived Intangible Asset, Useful Life	15 years
Revenue Recognition
Revenue, Performance Obligation, Description of Payment Terms	60
Restricted Stock Award
Award vesting period	4 years
Maximum | Subscription and Circulation [Member]
Revenue Recognition
Capitalized Contract Cost, Amortization Period	5 years
Maximum | Software and Software Development Costs [Member]
Segment Reporting [Abstract]
Finite-Lived Intangible Asset, Useful Life	10 years

Summary Of Significant Accoun_4

Summary Of Significant Accounting Policies - Schedule Of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Accounting Policies [Abstract]
Finished goods	$ 11,699	$ 10,164
Raw materials	24,175	58,201
Inventories, Total	$ 35,874	$ 68,365

Summary Of Significant Accoun_5

Summary Of Significant Accounting Policies - Property And Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Line Items]
Computer equipment	$ 189,555	$ 168,204
Capitalized Computer Software, Gross	78,184	86,036
Office furniture and equipment	44,525	41,619
Leasehold improvements	185,225	173,689
Property and equipment, gross	497,489	469,548
Accumulated depreciation and amortization	(327,067)	(301,366)
Property, Plant and Equipment, Net	$ 170,422	$ 168,182
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Summary Of Significant Accoun_6

Summary Of Significant Accounting Policies - Schedule Of Computation Of Basic And Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Accounting Policies [Abstract]
Net income	$ 394,948	$ 322,160	$ 331,241
Weighted average shares outstanding - basic	59,909	60,274	60,707
Dilutive effect of common shares from stock options and restricted stock units	361	823	1,350
Weighted average shares outstanding - diluted	60,270	61,097	62,057
Basic net income per share (USD per share)	$ 6.59	$ 5.34	$ 5.46
Diluted net income per share (USD per share)	$ 6.55	$ 5.27	$ 5.34

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Capitalized Contract Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Capitalized Contract Acquisition Costs [Abstract]
Balance, beginning of year	$ 77,220	$ 77,836	$ 70,396
Additional capitalized contract acquisition costs	26,960	37,897	41,719
Amortization of capitalized contract acquisition costs	(37,712)	(38,513)	(34,279)
Balance, end of year	$ 66,468	$ 77,220	$ 77,836

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Change in Contract with Customer, Liability [Roll Forward]
Balance, beginning of year	$ 1,691,580	$ 1,489,842	$ 1,272,632
Amounts added but not recognized as revenues	1,162,698	1,167,143	1,122,081
Deferred revenue acquired through acquisition of businesses	1,800	10,591	779
Revenues recognized related to the opening balance of deferred revenue	(1,080,957)	(975,996)	(905,650)
Balance, end of year	$ 1,775,121	$ 1,691,580	$ 1,489,842

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Capitalized Contract Cost, Amortization	$ 37,712,000	$ 38,513,000	$ 34,279,000
Capitalized Contract Cost, Impairment Loss	$ 0	$ 0	$ 0

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Remaining Performance Obligations. (Details) $ in Billions	Sep. 30, 2023 USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 1.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Percentage	63.50%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Percentage	63.50%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Percentage	23.50%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Percentage	23.50%

Business Combinations - Purchas

Business Combinations - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Oct. 01, 2021	Jan. 22, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Fair Value of intangible Assets Abstract [Abstract]
Goodwill			$ 2,288,678	$ 2,259,282	$ 2,216,553
Threat Stack, Inc.
AssetsAcquiredAbstract [Abstract]
Cash, cash equivalents, and restricted cash	$ 911
Fair Value of intangible Assets Abstract [Abstract]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets	14,041
Other tangible assets acquired, at fair value	$ 5,481
Identifiable Intangible Assets Useful Life	5 years
Goodwill	$ 43,282
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Total	79,515
Liabilities Assumed Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue	(10,591)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(10,591)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net, Total	68,924
Threat Stack, Inc. | Developed Technology Rights
Fair Value of intangible Assets Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 11,400
Identifiable Intangible Assets Useful Life	5 years
Threat Stack, Inc. | Customer Relationships
Fair Value of intangible Assets Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 4,400
Identifiable Intangible Assets Useful Life	5 years
Volterra, Inc.
AssetsAcquiredAbstract [Abstract]
Cash, cash equivalents, and restricted cash		$ 14,012
Fair Value of intangible Assets Abstract [Abstract]
Other tangible assets acquired, at fair value		$ 7,499
Identifiable Intangible Assets Useful Life		6 years 11 months 12 days
Goodwill		$ 350,863
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets, Total		432,374
Liabilities Assumed Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(5,233)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net, Total		427,141
Volterra, Inc. | Developed Technology Rights
Fair Value of intangible Assets Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 59,500
Identifiable Intangible Assets Useful Life		7 years
Volterra, Inc. | Customer Relationships
Fair Value of intangible Assets Abstract [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 500
Identifiable Intangible Assets Useful Life		1 year

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($) $ in Millions			12 Months Ended
	Oct. 01, 2021	Jan. 22, 2021	Sep. 30, 2021
Threat Stack, Inc.
Business Acquisition [Line Items]
Total Purchase Price	$ 68.9
Identifiable Intangible Assets Useful Life	5 years
Volterra, Inc.
Business Acquisition [Line Items]
Total Purchase Price		$ 427.2
Identifiable Intangible Assets Useful Life		6 years 11 months 12 days
Volterra, Inc. | General and Administrative Expense
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs			$ 9.5
Developed Technology Rights | Threat Stack, Inc.
Business Acquisition [Line Items]
Identifiable Intangible Assets Useful Life	5 years
Developed Technology Rights | Volterra, Inc.
Business Acquisition [Line Items]
Identifiable Intangible Assets Useful Life		7 years
Customer Relationships | Threat Stack, Inc.
Business Acquisition [Line Items]
Identifiable Intangible Assets Useful Life	5 years
Customer Relationships | Volterra, Inc.
Business Acquisition [Line Items]
Identifiable Intangible Assets Useful Life		1 year

Fair Value Assets - Measured on

Fair Value Assets - Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value	$ 392,592	$ 287,932
Debt Securities, Available-for-sale, Amortized Cost	398,852	422,699
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	(100)	(1,787)
Debt Securities, Available-for-Sale	398,752	420,912
Debt Securities, Available-for-sale, Current	6,160	126,554
Debt Securities, Available-for-sale, Noncurrent	0	6,426
Equity Securities, FV-NI	5,068	3,118
Equity Securities, FV-NI, Current	0	0
Equity Securities, FV-NI, Noncurrent	5,068	3,118
Investments, Fair Value Disclosure	403,820	424,030
Short-term investments	6,160	126,554
Long-term investments	5,068	9,544
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value	392,592	276,294
Corporate Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	4,412	50,828
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	(88)	(950)
Municipal Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,108	5,018
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	(9)	(102)
US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	0	84,734
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	0	(660)
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	740	5,825
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax	(3)	(75)
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	5,068	3,118
Equity Securities, FV-NI, Current	0	0
Equity Securities, FV-NI, Noncurrent	5,068	3,118
Fair Value, Recurring [Member] | Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value	392,592	276,294
Fair Value, Recurring [Member] | Level 2 | Corporate Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value		912
Debt Securities, Available-for-Sale	4,324	49,878
Debt Securities, Available-for-sale, Current	4,324	44,356
Debt Securities, Available-for-sale, Noncurrent	0	4,610
Fair Value, Recurring [Member] | Level 2 | Municipal Bonds And Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-Sale	1,099	4,916
Debt Securities, Available-for-sale, Current	1,099	3,812
Debt Securities, Available-for-sale, Noncurrent	0	1,104
Fair Value, Recurring [Member] | Level 2 | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value		10,120
Debt Securities, Available-for-Sale	0	84,074
Debt Securities, Available-for-sale, Current	0	73,954
Debt Securities, Available-for-sale, Noncurrent	0	0
Fair Value, Recurring [Member] | Level 2 | US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents, fair value		606
Debt Securities, Available-for-Sale	737	5,750
Debt Securities, Available-for-sale, Current	737	4,432
Debt Securities, Available-for-sale, Noncurrent	$ 0	$ 712

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Impairment Charges by Income Statement Line Item (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Impairment of assets	$ 3,455	$ 6,175	$ 40,698
Cost of net product revenue
Property, Plant and Equipment [Line Items]
Impairment of assets	0	0	2,865
Cost of net service revenue
Property, Plant and Equipment [Line Items]
Impairment of assets	0	0	3,492
Selling and Marketing Expense
Property, Plant and Equipment [Line Items]
Impairment of assets	0	6,175	11,515
Research and Development Expense
Property, Plant and Equipment [Line Items]
Impairment of assets	0	0	12,974
General and Administrative Expense
Property, Plant and Equipment [Line Items]
Impairment of assets	0	0	9,852
Restructuring Charges
Property, Plant and Equipment [Line Items]
Impairment of assets	$ 3,455	$ 0	$ 0

Fair Value Measurements - Impai

Fair Value Measurements - Impairment of Assets Measured at Fair Value on a Nonrecurring Basis Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating Lease, Impairment Loss	$ 23.5	$ 6.7	$ 3.5
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)				$ 6.2
Operating Lease, Impairment Loss			$ 3.5
Fair Value, Nonrecurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating Lease, Impairment Loss	23.5	6.7
Tangible Asset Impairment Charges	$ 10.3	$ 0.2

Balance Sheet Details - Cash, C

Balance Sheet Details - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Balance Sheet Details [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 797,163	$ 758,012
Restricted Cash	3,672	4,195
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 800,835	$ 762,207	$ 584,333	$ 852,826

Balance Sheet Details - Invento

Balance Sheet Details - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Finished goods	$ 11,699	$ 10,164
Raw materials	24,175	58,201
Inventory, Net	$ 35,874	$ 68,365

Balance Sheet Details - Other C

Balance Sheet Details - Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Unbilled receivables	$ 374,113	$ 319,707
Prepaid expenses	84,506	57,340
Capitalized contract acquisition costs	31,206	34,658
Other1	64,919	77,609
Other Assets, Current	554,744	489,314
(1) Deposit Assets	$ 36,200	$ 57,000

Balance Sheet Details - Propert

Balance Sheet Details - Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Machinery and Equipment, Gross	$ 189,555	$ 168,204
Capitalized Computer Software, Gross	78,184	86,036
Furniture and Fixtures, Gross	44,525	41,619
Leasehold Improvements, Gross	185,225	173,689
Property, Plant and Equipment, Gross	497,489	469,548
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(327,067)	(301,366)
Property, Plant and Equipment, Net	$ 170,422	$ 168,182

Balance Sheet Details - Goodwil

Balance Sheet Details - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Goodwill, Beginning Balance	$ 2,259,282	$ 2,216,553
Goodwill, Acquired During Period	29,396	43,956
Goodwill, Other Increase (Decrease)		(1,227)
Goodwill, Ending Balance	$ 2,288,678	$ 2,259,282

Balance Sheet Details - Other A

Balance Sheet Details - Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Intangible assets	$ 150,969	$ 200,288
Unbilled receivables	202,838	224,780
Capitalized contract acquisition costs	35,263	42,561
Other	55,543	48,493
Other Assets, Noncurrent	$ 444,613	$ 516,122

Balance Sheet Details - Intangi

Balance Sheet Details - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 396,142	$ 416,315
Accumulated Amortization	(245,173)	(216,027)
Net Carrying Amount	150,969	200,288
Developed Technology Rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	319,368	319,436
Accumulated Amortization	(190,135)	(151,332)
Net Carrying Amount	129,233	168,104
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	45,642	46,142
Accumulated Amortization	(33,298)	(25,630)
Net Carrying Amount	12,344	20,512
Patents And Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	13,699	23,504
Accumulated Amortization	(9,658)	(19,255)
Net Carrying Amount	4,041	4,249
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,473	24,973
Accumulated Amortization	(10,122)	(17,550)
Net Carrying Amount	5,351	7,423
Non-Compete Covenants [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,960	2,260
Accumulated Amortization	(1,960)	(2,260)
Net Carrying Amount	$ 0	$ 0

Balance Sheet Details - Estimat

Balance Sheet Details - Estimated Amortization Expense For Intangible Assets (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Balance Sheet Details [Abstract]
2024	$ 50,914
2025	39,477
2026	34,723
2027	16,541
2028	4,106
Total estimated amortization expense	$ 145,761

Balance Sheet Details - Accrued

Balance Sheet Details - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Payroll and benefits	$ 152,898	$ 165,437
Operating lease liabilities, current	41,421	42,523
Income and other tax accruals	34,504	41,217
Other	54,067	60,642
Accrued Liabilities, Current	$ 282,890	$ 309,819

Balance Sheet Details - Other L

Balance Sheet Details - Other Long-term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Balance Sheet Details [Abstract]
Income taxes payable	$ 73,751	$ 59,553
Other	8,822	8,157
Other Liabilities, Noncurrent	$ 82,573	$ 67,710

Balance Sheet Details - Narrati

Balance Sheet Details - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Depreciation and amortization			$ 112,702	$ 115,609	$ 115,424
Amortization of Intangible Assets			29,100	36,400	48,700
Fair Value, Nonrecurring
Property, Plant and Equipment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)				6,200
Fair Value, Inputs, Level 3 | Fair Value, Nonrecurring
Property, Plant and Equipment [Line Items]
Tangible Asset Impairment Charges	$ 10,300	$ 200
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization			$ 53,300	$ 56,000	$ 61,300

Debt Facilities - Narrative (De

Debt Facilities - Narrative (Details)					2 Months Ended	12 Months Ended
	May 26, 2023	Dec. 15, 2022 USD ($)	Jan. 31, 2020 USD ($)	Jan. 24, 2020 USD ($)	Dec. 15, 2022	Sep. 30, 2023 USD ($) extension	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Debt Instrument [Line Items]
Repayments of Long-Term Debt						$ 350,000,000	$ 20,000,000	$ 20,000,000
Term Loan Facility [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount				$ 400,000,000
Redemption Percentage				1.25%
Debt Issuance Costs				$ 2,200,000			200,000
Repayments of Long-Term Debt		$ 350,000,000
Interest Expense, Long-Term Debt		$ 3,000,000
Line of Credit Facility, Interest Rate During Period					4.072%
Long-term Debt							$ 350,000,000
Interest Rate at Period End							2.19%	1.361%
Term Loan Facility [Member] | Minimum
Debt Instrument [Line Items]
Basis Spread on Variable Rate				1.125%
Term Loan Facility [Member] | Maximum
Debt Instrument [Line Items]
Basis Spread on Variable Rate				1.75%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Aggregate Principal Amount			$ 350,000,000
Conditional Increase In Borrowing Capacity			$ 150,000,000
Number Of Extensions | extension						2
Length Of Extension Period						1 year
Long-term Line of Credit						$ 0
Outstanding Line of Credit Balance						$ 350,000,000
Debt Instrument, Interest Rate, Basis for Effective Rate	0.10
Revolving Credit Facility [Member] | Minimum
Debt Instrument [Line Items]
Basis Spread on Variable Rate	1.125%		1.125%
Commitment Fee Percentage			0.125%
Revolving Credit Facility [Member] | Maximum
Debt Instrument [Line Items]
Basis Spread on Variable Rate	1.75%		1.75%
Commitment Fee Percentage			0.30%
Revolving Credit Facility [Member] | Alternate Base Rate [Member] | Minimum
Debt Instrument [Line Items]
Basis Spread on Variable Rate	0.125%		0.125%
Revolving Credit Facility [Member] | Alternate Base Rate [Member] | Maximum
Debt Instrument [Line Items]
Basis Spread on Variable Rate	0.75%		0.75%

Leases - Operating Lease Expens

Leases - Operating Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Leases [Abstract]
Operating lease expense	$ 47,036	$ 47,302	$ 47,993
Short-term lease expense	2,986	2,465	2,953
Variable lease expense	23,139	23,209	25,200
Total lease expense	$ 73,161	$ 72,976	$ 76,146

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Operating lease right-of-use assets	$ 195,471	$ 227,475
Operating lease liabilities, current1	41,421	42,523
Operating lease liabilities, long-term	239,565	272,376
Total lease liabilities	$ 280,986	$ 314,899
Weighted average remaining lease term (in years)	8 years 7 months 6 days	9 years 2 months 12 days
Weighted average discount rate	2.77%	2.66%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
2024	$ 48,709
2025	41,095
2026	31,559
2027	30,394
2028	28,340
Thereafter	138,797
Total lease payments	318,894
Less: imputed interest	(37,908)
Total lease liabilities	$ 280,986	$ 314,899

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2023 USD ($) ft²
Lessee, Lease, Description [Line Items]
Sublease Income			$ 14.7
Lessor, Operating Lease, Payments to be Received, Next Twelve Months			7.3
Lessor, Operating Lease, Payments to be Received, Years Two and Three			7.4
Operating Lease, Impairment Loss	$ 23.5	$ 6.7	$ 3.5
Office Building [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Number of Square Feet | ft²			515,000

Income Taxes - Components Of In

Income Taxes - Components Of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
United States	$ 268,314	$ 217,323	$ 189,398
International	217,674	168,070	197,539
Income before income taxes	$ 485,988	$ 385,393	$ 386,937

Income Taxes - Schedule Of Prov

Income Taxes - Schedule Of Provision For Income Taxes (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Current, U.S. federal	$ 115,170	$ 35,259	$ 53,107
Current, State	18,359	14,592	16,686
Current, Foreign	66,053	54,079	62,832
Total	199,582	103,930	132,625
Deferred, U.S. federal	(89,280)	(28,721)	(61,739)
Deferred, State	(18,576)	(11,332)	(15,294)
Deferred, Foreign	(686)	(644)	104
Total	(108,542)	(40,697)	(76,929)
Income taxes (benefit)	$ 91,040	$ 63,233	$ 55,696

Income Taxes - Schedule Of Effe

Income Taxes - Schedule Of Effective Tax Rate Differs From The U.S. Federal Statutory Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income tax provision at statutory rate	$ 102,058	$ 80,933	$ 81,257
State taxes, net of federal benefit	6,806	6,012	5,118
Tax impact of foreign operations	(20,230)	(21,435)	(26,881)
Research and development and other credits	(19,198)	(18,917)	(18,055)
Stock-based and other compensation	20,145	15,070	12,740
Other	1,459	1,570	1,517
Income taxes (benefit)	$ 91,040	$ 63,233	$ 55,696

Income Taxes - Schedule Of Tax

Income Taxes - Schedule Of Tax Effects To Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Net operating loss carry-forwards	$ 40,201	$ 42,849
Capitalized research and development costs	267,744	158,206
Accrued compensation and benefits	11,995	14,068
Stock-based compensation	8,875	10,389
Deferred revenue	42,544	32,244
Lease liabilities	62,405	67,520
Other accruals and reserves	22,723	18,797
Tax credit carryforwards	23,883	28,858
Depreciation	531	505
Total deferred tax assets before deferred liabilities	480,901	373,436
Valuation allowance	(43,942)	(46,136)
Deferred tax assets, net of valuation allowance	436,959	327,300
Purchased intangibles	(55,519)	(57,350)
Depreciation	(28,113)	(22,278)
Deferred costs	(11,031)	(12,987)
Lease assets	(41,709)	(45,948)
Other accruals and reserves	(9,916)	(8,153)
Total deferred tax liabilities	(146,288)	(146,716)
Net deferred tax assets	$ 290,671	$ 180,584

Income Taxes - Schedule Of Reco

Income Taxes - Schedule Of Reconciliation Of Beginning And Ending Amount Of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, beginning of period	$ 66,840	$ 70,814	$ 51,767
Gross increases related to prior period tax positions	4,270	4,816	14,867
Gross decreases related to prior period tax positions	(70)	(10,538)	0
Gross increases related to current period tax positions	9,224	10,203	12,595
Decreases relating to settlements with tax authorities	(300)	0	(321)
Reductions due to lapses of statute of limitations	(797)	(8,455)	(8,094)
Balance, end of period	$ 79,167	$ 66,840	$ 70,814

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Operating Loss Carryforwards [Line Items]
Income Tax Holiday, Aggregate Dollar Amount	$ 6,000	$ 8,500	$ 6,000
Income Tax Holiday, Income Tax Benefits Per Share	$ 0.10	$ 0.14	$ 0.10
Deferred Tax Assets, Operating Loss Carryforwards	$ 40,201	$ 42,849
Deferred Tax Assets, Tax Credit Carryforwards	23,883	28,858
Valuation Allowance, Deferred Tax Asset, Change in Amount	(2,200)	5,700
Unrecognized Tax Benefits	79,167	66,840	$ 70,814	$ 51,767
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	51,200	43,200	39,200
Unrecognized Tax Benefits, Period Increase (Decrease)	3,300	(1,500)	$ 1,400
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	6,200	$ 2,900
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	56,900
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	300
Deferred Tax Assets, Tax Credit Carryforwards	200
Deferred Tax Assets, Tax Credit Carryforwards, Subject to Expiration	3,200
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	56,400
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	23,400
Deferred Tax Assets, Operating Loss Carryforwards	79,800
Deferred Tax Assets, Tax Credit Carryforwards, Subject to Expiration	3,200
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	47,000
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	191,800
Deferred Tax Assets, Operating Loss Carryforwards	238,800
Deferred Tax Assets, Tax Credit Carryforwards	30,200
Deferred Tax Assets, Tax Credit Carryforwards, Subject to Expiration	$ 3,700

Shareholders' Equity - Class of

Shareholders' Equity - Class of Treasury Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Equity, Class of Treasury Stock [Line Items]
Treasury Stock Acquired, Average Cost Per Share	$ 194.91	$ 199.90	$ 142.62	$ 191.47	$ 199.90
Stock Repurchased and Retired During Period, Value			$ 350,049	$ 500,023	$ 500,000
October 26, 2010 Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased and Retired During Period, Shares			2,454	2,611	2,501

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Jul. 25, 2022	Jun. 30, 2022	Feb. 03, 2021
Common Stock Repurchase [Line Items]
Accelerated Share Repurchases, Settlement (Payment) or Receipt		$ 400							$ 500
Treasury Stock Acquired, Average Cost Per Share		$ 194.91	$ 199.90	$ 142.62	$ 191.47	$ 199.90
Accelerated Share Repurchases, Cash or Stock Settlement	449,049	2.1 million	2.5 million
Adjustments To Additional Paid In Capital, Equity Forward Contract	$ 100
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 922
October Twenty Six Two Thousand Ten Program [Member]
Common Stock Repurchase [Line Items]
Stock Repurchase Program, Authorized Amount							$ 1,000	$ 5,400

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions (Details)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Fair Value Assumptions
Expected dividend	0%	0%	0%
Expected term	6 months	6 months	6 months
Minimum
Fair Value Assumptions
Risk-free interest rate	3.18%	0.05%	0.07%
Expected volatility	33.02%	26.34%	29.67%
Maximum
Fair Value Assumptions
Risk-free interest rate	4.90%	0.62%	0.13%
Expected volatility	38.15%	31.57%	37.22%
Two Thousand Eleven Employee Stock Purchase Plan [Member]
Fair Value Assumptions
Expected term	6 months

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule Of Summary Of Restricted Stock Unit Activity (Details)	12 Months Ended
	Sep. 30, 2023 $ / shares shares
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 206.13
Weighted Average Grant Date Fair Value, Ending balance	$ 144.78
Performance Shares [Member] | Two Thousand Fourteen Equity Incentive Plan [Member]
Outstanding Restricted Stock Units
Outstanding Stock Units, Beginning balance | shares	208,116
Outstanding Stock Units, Units granted | shares	131,491
Outstanding Stock Units, Units vested | shares	(92,677)
Outstanding Stock Units, Units cancelled | shares	(47,012)
Outstanding Stock Units, Ending balance | shares	199,918
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 169.99
Weighted Average Grant Date Fair Value, Units granted	145.02
Weighted Average Grant Date Fair Value, Units vested	144.69
Weighted Average Grant Date Fair Value, Units cancelled	171.07
Weighted Average Grant Date Fair Value, Ending balance	$ 159.37
Restricted Stock Units (RSUs) [Member] | Two Thousand Fourteen Equity Incentive Plan [Member]
Outstanding Restricted Stock Units
Outstanding Stock Units, Beginning balance | shares	1,137,619
Outstanding Stock Units, Units granted | shares	1,448,427
Outstanding Stock Units, Units vested | shares	(1,113,259)
Outstanding Stock Units, Units cancelled | shares	(247,401)
Outstanding Stock Units, Ending balance | shares	1,225,386
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 184.59
Weighted Average Grant Date Fair Value, Units granted	145.10
Weighted Average Grant Date Fair Value, Units vested	147.10
Weighted Average Grant Date Fair Value, Units cancelled	162.80
Weighted Average Grant Date Fair Value, Ending balance	$ 156.89

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details) - $ / shares	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 months	6 months	6 months
Expected dividend	0%	0%	0%
Tranche 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value, Per Share	$ 157.36
Expected term	10 months 28 days
Risk-free interest rate	4.66%
Expected dividend	0%
Tranche 1 [Member] | F5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	37.17%
Tranche 1 [Member] | Index Members [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	35.56%
Tranche 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value, Per Share	$ 173.68
Expected term	1 year 10 months 28 days
Risk-free interest rate	4.51%
Expected dividend	0%
Tranche 2 [Member] | F5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	31.84%
Tranche 2 [Member] | Index Members [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	31.74%
Tranche 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value, Per Share	$ 194.41
Expected term	2 years 10 months 28 days
Risk-free interest rate	4.44%
Expected dividend	0%
Tranche 3 [Member] | F5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	35.50%
Tranche 3 [Member] | Index Members [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	40.59%

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Details) - shares	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	2 years	2 years	2 years
Annual Equity Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Annual Performance Stock Grant Vests In Equal Quarterly Increments	50%
Percentage Of Annual Performance Stock Grant Based On Achieving Specified Annual Performance Goals	50%
Annual Equity Program [Member] | CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Annual Performance Stock Grant Vests In Equal Quarterly Increments	40%
Percentage Of Annual Performance Stock Grant Based On Achieving Specified Annual Performance Goals	60%
Annual Equity Program [Member] | November 1, 2022 | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period	240,808
Award vesting period	3 years
Annual Equity Program [Member] | November 1, 2021 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period	160,384
Award vesting period	3 years
Annual Equity Program [Member] | November 2, 2020 | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period	257,568
Award vesting period	3 years
Annual Equity Program [Member] | November 1, 2019 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period	228,616
Award vesting period	3 years

Stock-Based Compensation - Sc_5

Stock-Based Compensation - Schedule Of Stock Option Activity (Details)	12 Months Ended
	Sep. 30, 2023 $ / shares shares
Number of Shares
Number of Shares, Beginning balance | shares	164,796
Number of Shares, Options granted | shares	2,051
Number of Shares, Options exercised | shares	(56,516)
Number of Shares, Options cancelled | shares	(4,463)
Number of Shares, Ending balance | shares	105,868
Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share, Beginning balance | $ / shares	$ 33.34
Weighted Average Exercise Price per Share, Options granted | $ / shares	4.55
Weighted Average Exercise Price per Share, Options exercised | $ / shares	26.38
Weighted Average Exercise Price per Share, Options cancelled | $ / shares	61.35
Weighted Average Exercise Price per Share, Ending balance | $ / shares	$ 35.31

Stock-Based Compensation - Sc_6

Stock-Based Compensation - Schedule Of Outstanding Stock Options Currently Exercisable, Vested And Expected To Vest (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Stock options outstanding	105,868	164,796
Stock options outstanding, Weighted Average Remaining Contractual Life (in Years)	5 years 7 months 13 days
Stock options outstanding, Weighted Average Exercise Price per Share	$ 35.31	$ 33.34
Stock options outstanding, Aggregate Intrinsic Value	$ 13,321
Exercisable, Number of Shares	99,067
Exercisable, Weighted Average Remaining Contractual Life (in Years)	5 years 6 months 14 days
Exercisable, Weighted Average Exercise Price per Share	$ 35.47
Exercisable, Aggregate Intrinsic Value	$ 12,449
Vested and expected to vest, Number of Shares	105,561
Vested and expected to vest, Weighted Average Remaining Contractual Life (in Years)	5 years 7 months 9 days
Vested and expected to vest, Weighted Average Exercise Price per Share	$ 35.36
Vested and expected to vest, Aggregate Intrinsic Value	$ 13,277

Stock-Based Compensation - Sc_7

Stock-Based Compensation - Schedule Of Equity Based Awards (Including Stock Options And Restricted Stock Units (Details) - Equity Based Awards [Member]	12 Months Ended
	Sep. 30, 2023 shares
Awards Available for Grant
Awards Available for Grant, Beginning balance	2,072,778
Awards Available for Grant, Granted	(1,629,873)
Awards Available for Grant, Cancelled	349,715
Additional shares reserved (terminated), net	4,504,183
Awards Available for Grant, Ending balance	5,296,803

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)		12 Months Ended
	Oct. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Feb. 01, 2023	Oct. 01, 2021	Jan. 22, 2021	Jan. 24, 2020	May 08, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		$ 236,700,000	$ 249,200,000	$ 243,300,000
Share-based Payment Arrangement, Expense, Tax Benefit		44,700,000	$ 47,300,000	$ 44,100,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount		$ 162,700,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition		2 years
Expected term		6 months	6 months	6 months
Weighted Average Grant Date Fair Value		$ 144.78	$ 206.13	$ 145.89
Fair market value of restricted stock vested		$ 195,900,000	$ 262,400,000	$ 261,900,000
Total intrinsic value of options exercised		$ 6,900,000	$ 25,600,000	$ 25,600,000
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period	1,256,510
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		2 years	2 years	2 years
Two Thousand Eleven Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		12,000,000
Percentage of base compensation for which employees can acquire shares of common stock		15%
Maximum shares allowed for purchase by employee in period		10,000
Maximum aggregate fair value of stock that an employee may purchase		$ 25,000
Expected term		6 months
Percentage of common stock lesser of the fair market value		85%
Number of Shares Authorized		2,444,575
Nginx Acquisition Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance									183,061
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Nginx Acquisition Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		19
Nginx, Inc. 2011 Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance									302,634
Nginx, Inc. 2011 Share Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for purchase under stock option plan		6,010
Shape Acquisition Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance								450,000
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Shape Acquisition Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		20,754
Shape 2011 Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance								501,085
Shape 2011 Share Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for purchase under stock option plan		51,144
Volterra Acquisition Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance							140,000
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Volterra Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		39,472
Volterra 2017 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance							261,696
Volterra 2017 Stock Plan | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		7,171
Volterra 2017 Stock Plan | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for purchase under stock option plan		46,778
Threat Stack Acquisition Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance						35,000
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Threat Stack Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		6,915
Lilac Acquisition Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance					55,000
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Lilac Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock units		47,904
Shares Issued in Period		47,904
Lilac Cloud 2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance					4,485
Lilac Cloud 2018 Equity Incentive Plan | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for purchase under stock option plan		1,936
Shares Issued in Period		2,051
Two Thousand Fourteen Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		27,880,000
Vesting rate of stock options and awards upon certain changes in ownership control		50%
Number of Shares Authorized		5,287,273
Two Thousand Fourteen Equity Incentive Plan [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period		131,491
Outstanding stock units		199,918	208,116
Shares Issued in Period		131,491
Weighted Average Grant Date Fair Value		$ 159.37	$ 169.99
Two Thousand Fourteen Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Grants in Period		1,448,427
Outstanding stock units		1,225,386	1,137,619
Shares Issued in Period		1,448,427
Weighted Average Grant Date Fair Value		$ 156.89	$ 184.59

Net Income Per Share (Details)

Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Net Income Per Share [Abstract]
Net income	$ 394,948	$ 322,160	$ 331,241
Weighted average shares - basic (shares)	59,909	60,274	60,707
Weighted Average Number Diluted Shares Outstanding Adjustment	361	823	1,350
Weighted Average Number of Shares Outstanding, Diluted	60,270	61,097	62,057
Net income per share - basic (USD per share)	$ 6.59	$ 5.34	$ 5.46
Net income per share - diluted (USD per share)	$ 6.55	$ 5.27	$ 5.34

Commitments And Contingencies N

Commitments And Contingencies Narrative (Details) - USD ($) $ in Millions	Apr. 11, 2023	Oct. 27, 2022	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Unrecorded Unconditional Purchase Obligation, to be Paid, Year One		$ 10
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two		10
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three		10
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four		10
Unrecorded Unconditional Purchase Obligation		$ 40	$ 30
Unrecorded Unconditional Purchase Obligation, Term		4 years
Litigation Settlement, Amount Awarded from Other Party	$ 0.8

Restructuring Charges (Details)

Restructuring Charges (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2023 USD ($) Rate	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 65,388	$ 7,909	$ 0
Q3 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 56,700
Number of employees affected	620
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent | Rate	9%
Severance Costs	$ 53,200
Other Restructuring Costs	3,500
Payments for Restructuring	49,700
Restructuring Reserve	3,500
Q1 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 8,700
Q1 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 7,900

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Contributions by the Company to the plan	$ 13.7	$ 14	$ 13.2
Employer contribution, vesting period	4 years	4 years	4 years

Segment Information (Details)

Segment Information (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2023 USD ($) geographic_region	Sep. 30, 2022 USD ($) geographic_region	Sep. 30, 2021 USD ($) geographic_region
Segment Reporting Information [Line Items]
Number of Geographic Regions | geographic_region	3	3	3
Net revenues	$ 2,813,169	$ 2,695,845	$ 2,603,416
Property and equipment, net	$ 170,422	$ 168,182
Customer One [Member] | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	15.60%	20%	19.20%
Customer One [Member] | Geographic Concentration Risk [Member] | Accounts Receivable [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	0%	12.90%
Customer Two [Member] | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	15%	13.40%	11.10%
Customer Two [Member] | Geographic Concentration Risk [Member] | Accounts Receivable [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	16%	12.60%
Customer Three [Member] | Geographic Concentration Risk [Member] | Accounts Receivable [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	10.10%	16.20%
Product [Member]
Segment Reporting Information [Line Items]
Net revenues	$ 1,334,638	$ 1,317,117	$ 1,247,084
Product [Member] | Systems
Segment Reporting Information [Line Items]
Net revenues	670,652	651,902	748,192
Product [Member] | Software
Segment Reporting Information [Line Items]
Net revenues	663,986	665,215	498,892
United States [Member]
Segment Reporting Information [Line Items]
Net revenues	1,487,416	1,487,144	1,365,625
Property and equipment, net	125,736	134,699
Other Americas [Member]
Segment Reporting Information [Line Items]
Net revenues	96,958	85,711	92,111
Property and equipment, net	2,592	1,773
Americas [Member]
Segment Reporting Information [Line Items]
Net revenues	1,584,374	1,572,855	1,457,736
Property and equipment, net	128,328	136,472
EMEA [Member]
Segment Reporting Information [Line Items]
Net revenues	741,598	634,759	667,219
Property and equipment, net	24,336	17,376
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net revenues	487,197	488,231	$ 478,461
Property and equipment, net	$ 17,758	$ 14,334