F5 (FFIV) 10-Q 5 Feb 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2019	Jan. 31, 2020
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	000-26041
Entity Registrant Name	F5 NETWORKS, 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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,804,090
Entity Central Index Key	0001048695
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Current assets
Cash and cash equivalents	$ 735,457	$ 599,219
Short-term investments	426,761	373,063
Accounts receivable, net of allowances of $3,304 and $3,259	354,668	322,029
Inventories	32,381	34,401
Other current assets	188,204	182,874
Total current assets	1,737,471	1,511,586
Property and equipment, net	229,800	223,426
Operating lease right-of-use assets	303,435	0
Long-term investments	312,044	358,402
Deferred tax assets	29,380	27,701
Goodwill	1,065,379	1,065,379
Other assets, net	197,851	203,781
Total assets	3,875,360	3,390,275
Current liabilities
Accounts payable	52,407	62,627
Accrued liabilities	250,350	235,869
Deferred revenue	847,750	807,030
Total current liabilities	1,150,507	1,105,526
Deferred tax liabilities	258	313
Operating lease liabilities, long-term	342,303	0
Deferred revenue, long-term	390,223	391,086
Other long-term liabilities	62,611	131,853
Total long-term liabilities	795,395	523,252
Commitments and contingencies (Note 8)
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, 60,803 and 60,367 shares issued and outstanding	211,217	142,597
Accumulated other comprehensive loss	(18,376)	(19,190)
Retained earnings	1,736,617	1,638,090
Total shareholders’ equity	1,929,458	1,761,497
Total liabilities and shareholders’ equity	$ 3,875,360	$ 3,390,275

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 3,304	$ 3,259
Preferred stock, par value (dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (dollars per share)	$ 0	$ 0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	60,803,000	60,367,000

Consolidated Income Statements

Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Net revenues
Revenue from contract with customer, excluding assessed tax	$ 569,305	$ 543,770
Cost of net revenues
Cost of net revenues	88,642	86,714
Gross profit	480,663	457,056
Operating expenses
Sales and marketing	195,519	164,259
Research and development	96,005	92,038
General and administrative	59,004	42,543
Restructuring charges	7,800	0
Total	358,328	298,840
Income from operations	122,335	158,216
Other income, net	5,220	7,095
Income before income taxes	127,555	165,311
Provision for income taxes	29,028	34,406
Net income	$ 98,527	$ 130,905
Net income per share — basic (dollars per share)	$ 1.62	$ 2.17
Weighted average shares — basic (shares)	60,649	60,216
Net income per share — diluted (dollars per share)	$ 1.62	$ 2.16
Weighted average shares — diluted (shares)	60,815	60,645
Product
Net revenues
Revenue from contract with customer, excluding assessed tax	$ 234,536	$ 233,877
Cost of net revenues
Cost of net revenues	42,118	42,410
Service
Net revenues
Revenue from contract with customer, excluding assessed tax	334,769	309,893
Cost of net revenues
Cost of net revenues	$ 46,524	$ 44,304

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 98,527	$ 130,905
Other comprehensive income:
Foreign currency translation adjustment	634	141
Available-for-sale securities:
Unrealized gains on securities, net of taxes of $28 and $65 for the three months ended December 31, 2019 and 2018, respectively	189	44
Reclassification adjustment for realized gains included in net income, net of taxes of $2 and $0 for the three months ended December 31, 2019 and 2018, respectively	(9)	0
Net change in unrealized gains on available-for-sale securities, net of tax	180	44
Total other comprehensive income	814	185
Comprehensive income	$ 99,341	$ 131,090

Consolidated Statements Of Co_2

Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Tax effect of unrealized gain (loss) on securities	$ 28	$ 65
Tax effect of reclassification adjustment for realized (gains) losses	$ 2	$ 0

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	AOCI Attributable to Parent	Retained Earnings
Beginning Balance (in shares) at Sep. 30, 2018		60,215
Beginning Balance at Sep. 30, 2018	$ 1,285,492	$ 20,427	$ (22,178)	$ 1,287,243
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under employee stock purchase plan (in shares)		135
Issuance of stock under employee stock purchase plan	18,900	$ 18,900
Issuance of restricted stock (in shares)		277
Repurchase of common stock (in shares)		(569)
Repurchase of common stock	(101,031)	$ (64,739)		(36,292)
Stock-based compensation	38,689	$ 38,689
Net income	130,905			130,905
Other comprehensive income	185		185
Ending Balance ( in shares) at Dec. 31, 2018		60,058
Ending Balance at Dec. 31, 2018	$ 1,409,188	$ 13,277	(21,993)	1,417,904
Beginning Balance (in shares) at Sep. 30, 2019	60,367	60,367
Beginning Balance at Sep. 30, 2019	$ 1,761,497	$ 142,597	(19,190)	1,638,090
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under employee stock purchase plan (in shares)		169
Issuance of stock under employee stock purchase plan	20,669	$ 20,669
Exercise of employee stock options (in shares)		11
Exercise of employee stock options	290	$ 290
Issuance of restricted stock (in shares)		256
Stock-based compensation	47,661	$ 47,661
Net income	98,527			98,527
Other comprehensive income	$ 814		814
Ending Balance ( in shares) at Dec. 31, 2019	60,803	60,803
Ending Balance at Dec. 31, 2019	$ 1,929,458	$ 211,217	$ (18,376)	$ 1,736,617

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income	$ 98,527	$ 130,905
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	47,661	38,689
Depreciation and amortization	18,979	14,001
Non-cash operating lease costs	8,703	0
Other	(31)	251
Deferred income taxes	(1,714)	2,714
Changes in operating assets and liabilities:
Accounts receivable	(32,683)	(28,921)
Inventories	2,020	(991)
Other current assets	(5,494)	(26,777)
Other assets	2,011	(157)
Accounts payable and accrued liabilities	(23,606)	2,022
Deferred revenue	39,856	66,122
Lease liabilities	(10,217)
Net cash provided by operating activities	144,012	197,858
Investing activities
Purchases of investments	(180,557)	(190,884)
Maturities of investments	150,697	151,537
Sales of investments	22,764	0
Purchases of property and equipment	(22,304)	(21,046)
Net cash used in investing activities	(29,400)	(60,393)
Financing activities
Proceeds from the exercise of stock options and purchases of stock under employee stock purchase plan	20,959	18,900
Repurchase of common stock	0	(101,032)
Net cash provided by (used in) financing activities	20,959	(82,132)
Net increase in cash, cash equivalents and restricted cash	135,571	55,333
Effect of exchange rate changes on cash, cash equivalents and restricted cash	820	46
Cash, cash equivalents and restricted cash, beginning of period	602,254	425,894
Cash, cash equivalents and restricted cash, end of period	738,645	481,273
Supplemental disclosures of cash flow information
Cash paid for amounts included in the measurement of operating lease liabilities	12,707
Supplemental disclosures of non-cash activities
Right-of-use assets obtained in exchange for lease obligations	394,315
Capitalized leasehold improvements paid directly by landlord	$ 0	$ 15,384

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Description of Business F5 Networks, Inc. (the “Company”) is a leading provider of multi-cloud application services 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, installation, maintenance, and other technical support services. Basis of Presentation The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. In the opinion of management, the unaudited consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary for their fair statement in conformity with accounting principles generally accepted in the United States of America. Certain information and footnote disclosures normally included in annual financial statements have been condensed or omitted in accordance with the rules and regulations of the Securities and Exchange Commission. The information included in this Form 10-Q should be read in conjunction with Management’s Discussion and Analysis of Financial Condition and Results of Operations and financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2019 . Certain prior year amounts have been reclassified to conform to the current year presentation in the Consolidated Statements of Cash Flows. The reclassified amounts are considered immaterial and there was no change to total cash from operating, investing or financing activities as a result. There have been no material changes to the Company's significant accounting policies as of and for the three months ended December 31, 2019 , except for the accounting policy for leases that was updated as a result of adopting Accounting Standards Update 2016-02, Leases (Topic 842) (ASU 2016-02) and related standards. For more information, refer to the "Recently Adopted Accounting Standards" section of Note 1 and Note 7 - Leases. Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (ASU 2016-02), which requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a corresponding lease liability for all leases with terms greater than twelve months. The Company’s leases consist primarily of operating leases for its offices and lab spaces. The Company does not have finance leases. The guidance also requires qualitative and quantitative disclosures designed to assess the amount, timing and uncertainty of cash flows arising from leases. The Company adopted this standard on October 1, 2019 on a modified retrospective basis by applying the new standard to its lease portfolio as of October 1, 2019, while continuing to apply legacy guidance in the comparative periods. The adoption of this standard had no impact on the consolidated income statements and consolidated statements of cash flows. Refer to Note 7 - Leases for further discussion. Upon adoption of the standard, the Company elected the package of three expedients for existing and expired contracts to not reassess: the existence of additional leases, lease classification, or the treatment of initial direct costs. The Company also applies the short-term lease exemption for leases with an original expected term of 12 months or less and expenses such leases month-to-month and does not record a right-of-use asset or lease liability. Short-term lease activity under the exception is not significant. Additionally, the Company does not separate lease and non-lease components in the allocation of minimum lease payments for its office space and equipment leases, as such separation is not significant. The Company includes in minimum lease payments, fixed and variable payments based on a rate or index, but excludes variable payments based on satisfying future benchmarks or actual future costs incurred; such amounts are expensed as incurred. To calculate the net present value, the Company applied an incremental borrowing rate. This incremental borrowing rate is determined using a portfolio approach based on the rate of interest the Company would pay to borrow an amount equal to the lease payments on a collateralized basis over a similar term . Renewal options to extend lease terms are excluded from the minimum lease term at lease commencement. Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not anticipate that the adoption of this standard will have a material impact on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) (ASU 2018-15), which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software, and hosting arrangements that include an internal use software license. The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this update. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not anticipate that the adoption of this standard will have a material impact on its consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts 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 three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 59,446 Additional capitalized contract acquisition costs deferred 7,412 Amortization of capitalized contract acquisition costs (8,705 ) Balance, December 31, 2019 $ 58,153 Amortization of capitalized contract acquisition costs was $8.7 million and $7.3 million for the three months ended December 31, 2019 and 2018, 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 our contracts with customers. The Company records assets for amounts related to performance obligations that are satisfied but not yet billed and/or collected, in addition to contracts that have started, but not yet been fully billed. These assets are recorded as contract assets rather than receivables when receipt of the consideration is conditional on something other than the passage of time. Liabilities are recorded for amounts that are collected in advance of the satisfaction of performance obligations. These liabilities are classified as current and non-current deferred revenue. The table below shows significant movements in contract assets (current and noncurrent) for the three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 132,492 Revenue recognized during period but not yet billed 3,407 Contract asset net additions 12,930 Contract assets reclassified to accounts receivable (13,584 ) Balance, December 31, 2019 $ 135,245 As of December 31, 2019 , contract assets that are expected to be reclassified to receivables within the next 12 months are included in other current assets, with those expected to be transferred to receivables in more than 12 months included in other assets. There were no impairments of contract assets during the three months ended December 31, 2019 and 2018. The table below shows significant movements in the deferred revenue balances (current and noncurrent) for the three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 1,198,116 Amounts billed but not recognized as revenues 346,132 Revenues recognized related to the opening balance of deferred revenue (306,275 ) Balance, December 31, 2019 $ 1,237,973 Our contract assets and liabilities are reported in a net position on a contract by contract basis at the end of each reporting period. 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. As of December 31, 2019, the total non-cancelable remaining performance obligations under the Company's contracts with customers was approximately $1.2 billion and the Company expects to recognize revenues on approximately 68.5% of these remaining performance obligations over the next 12 months, 18.7% in year two, and the remaining balance thereafter. See Note 11, Segment Information, for disaggregated revenue by significant customer and geographic region.

Business Combinations

Business Combinations	3 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combinations	Business Combinations Fiscal Year 2019 Acquisition of Nginx, Inc. On March 9, 2019, the Company entered into a Merger Agreement (the “Merger Agreement”) with Nginx, Inc. ("NGINX"), a provider of open source web server software and application delivery solutions. The transaction closed on May 8, 2019 with NGINX becoming a wholly-owned subsidiary of F5. Pursuant to the Merger Agreement, at the effective time of the Merger, the capital stock of NGINX and the vested outstanding and unexercised stock options in NGINX were cancelled and converted to the right to receive approximately $643.2 million in cash, subject to certain adjustments and conditions set forth in the Merger Agreement, and the unvested stock options and restricted stock units in NGINX held by continuing employees of NGINX were assumed by F5, on the terms and conditions set forth in the Merger Agreement. Included in cash consideration was $19.0 million of transaction costs paid by F5 on behalf of NGINX. In addition, the Company incurred an additional $1.0 million of transaction costs associated with the acquisition which was included in General and Administrative expenses for fiscal 2019. NGINX is an open source leader in application delivery. The combined company will enable multi-cloud application services across all environments, providing the ease-of-use and flexibility developers require while also delivering the scale, security, reliability and enterprise readiness network operations teams demand. As a result of the acquisition, the Company acquired all the assets and assumed all the liabilities of NGINX. The goodwill related to the NGINX acquisition is comprised primarily of expected synergies from combining operations and the acquired intangible assets that do not qualify for separate recognition. The results of operations of NGINX have been included in the Company’s consolidated financial statements from the date of acquisition. The purchase price allocation is as follows (in thousands): Assets acquired Cash and cash equivalents $ 29,911 Fair value of tangible assets: Accounts receivable 7,306 Other current assets 4,214 Property and equipment, net 1,822 Deferred tax assets 10,357 Intangible assets 89,300 Goodwill 509,414 Total assets acquired $ 652,324 Liabilities assumed Accounts payable $ (1,081 ) Deferred revenue (4,000 ) Other liabilities (4,035 ) Total liabilities assumed $ (9,116 ) Net assets acquired $ 643,208 The allocation of the purchase price and the estimated useful lives associated with certain assets is as follows (in thousands): Estimated Amount Useful Life Net tangible assets $ 44,494 — Identifiable intangible assets: Developed technologies 62,500 7 years Customer relationships 12,000 15 years Trade name 14,500 7 years Non-competition agreements 300 2 years Goodwill 509,414 — Total purchase price $ 643,208 The developed technology intangible asset will be amortized on a straight-line basis over its estimated useful life of seven years and included in cost of net product revenues. The trade names and customer relationships intangible assets will be amortized on a straight-line basis over their estimated useful lives of seven years and fifteen years, respectively, and included in sales and marketing expenses. The weighted average life of the amortizable intangible assets recognized from the NGINX merger was 8.1 years . The estimated useful lives for the acquired intangible assets were based on the expected future cash flows associated with the respective asset. Tax deductible goodwill based on the Company's preliminary calculation is $450.7 million . Since the NGINX acquisition was completed on May 8, 2019, the F5 and NGINX teams have been rapidly executing a plan to integrate ongoing operations.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements In 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. The Company’s financial assets measured at fair value on a recurring basis subject to the disclosure requirements at December 31, 2019 , were as follows (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at December 31, Cash equivalents $ 249,178 $ 42,387 $ — $ 291,565 Short-term investments Available-for-sale securities — certificates of deposits — 991 — 991 Available-for-sale securities — corporate bonds and notes — 264,425 — 264,425 Available-for-sale securities — municipal bonds and notes — 9,190 — 9,190 Available-for-sale securities — U.S. government securities — 131,808 — 131,808 Available-for-sale securities — U.S. government agency securities — 20,347 — 20,347 Long-term investments Available-for-sale securities — corporate bonds and notes — 274,477 — 274,477 Available-for-sale securities — U.S. government securities — 7,559 — 7,559 Available-for-sale securities — U.S. government agency securities — 30,008 — 30,008 Total $ 249,178 $ 781,192 $ — $ 1,030,370 The Company’s financial assets measured at fair value on a recurring basis subject to the disclosure requirements at September 30, 2019 , were as follows (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at September 30, 2019 Cash equivalents $ 140,238 $ 153,404 $ — $ 293,642 Short-term investments Available-for-sale securities — certificates of deposits — 249 — 249 Available-for-sale securities — corporate bonds and notes — 259,547 — 259,547 Available-for-sale securities — municipal bonds and notes — 12,129 — 12,129 Available-for-sale securities — U.S. government securities — 78,992 — 78,992 Available-for-sale securities — U.S. government agency securities — 22,146 — 22,146 Long-term investments Available-for-sale securities — corporate bonds and notes — 298,916 — 298,916 Available-for-sale securities — municipal bonds and notes — 2,524 — 2,524 Available-for-sale securities — U.S. government securities — 5,515 — 5,515 Available-for-sale securities — U.S. government agency securities — 51,447 — 51,447 Total $ 140,238 $ 884,869 $ — $ 1,025,107 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. The Company’s non-financial assets and liabilities, which include goodwill, intangible assets, and long-lived assets, are not required to be carried at fair value on a recurring basis. These non-financial assets and liabilities 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 and intangible assets 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 long-lived assets for impairment whenever events or changes in circumstances indicate its carrying amount may not be recoverable. During the three months ended December 31, 2019 and 2018, the Company did not recognize any impairment charges related to goodwill, intangible assets, or long-lived assets.

Short-Term and Long-Term Invest

Short-Term and Long-Term Investments	3 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Short-Term and Long-Term Investments	Short-Term and Long-Term Investments Short-term investments consist of the following (in thousands): December 31, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Certificates of deposits $ 991 $ — $ — $ 991 Corporate bonds and notes 264,006 463 (44 ) 264,425 Municipal bonds and notes 9,188 5 (3 ) 9,190 U.S. government securities 131,784 42 (18 ) 131,808 U.S. government agency securities 20,335 12 — 20,347 $ 426,304 $ 522 $ (65 ) $ 426,761 September 30, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Certificates of deposits $ 249 $ — $ — $ 249 Corporate bonds and notes 259,242 402 (97 ) 259,547 Municipal bonds and notes 12,128 6 (5 ) 12,129 U.S. government securities 78,988 18 (14 ) 78,992 U.S. government agency securities 22,138 9 (1 ) 22,146 $ 372,745 $ 435 $ (117 ) $ 373,063 Long-term investments consist of the following (in thousands): December 31, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Corporate bonds and notes $ 274,383 $ 267 $ (173 ) $ 274,477 U.S. government securities 7,558 5 (4 ) 7,559 U.S. government agency securities 30,035 — (27 ) 30,008 $ 311,976 $ 272 $ (204 ) $ 312,044 September 30, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Corporate bonds and notes $ 298,888 $ 469 $ (441 ) $ 298,916 Municipal bonds and notes 2,528 2 (6 ) 2,524 U.S. government securities 5,515 3 (3 ) 5,515 U.S. government agency securities 51,463 5 (21 ) 51,447 $ 358,394 $ 479 $ (471 ) $ 358,402 Interest income from investments was $5.6 million and $7.0 million for the three months ended December 31, 2019 and 2018, respectively. Interest income is included in other income, net on the Company's consolidated income statements. The following table summarizes investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for more than 12 months as of December 31, 2019 (in thousands): Less Than 12 Months 12 Months or Greater Total December 31, 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate bonds and notes $ 171,910 $ (180 ) $ 62,543 $ (37 ) $ 234,453 $ (217 ) Municipal bonds and notes 1,421 — 2,530 (3 ) 3,951 (3 ) U.S. government securities 79,687 (22 ) — — 79,687 (22 ) U.S. government agency securities 31,119 (27 ) — — 31,119 (27 ) Total $ 284,137 $ (229 ) $ 65,073 $ (40 ) $ 349,210 $ (269 ) The following table summarizes investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for more than 12 months as of September 30, 2019 (in thousands): Less Than 12 Months 12 Months or Greater Total September 30, 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate bonds and notes $ 237,747 $ (434 ) $ 109,613 $ (104 ) $ 347,360 $ (538 ) Municipal bonds and notes 864 — 7,800 (11 ) 8,664 (11 ) U.S. government securities 27,095 (12 ) 9,991 (5 ) 37,086 (17 ) U.S. government agency securities 30,946 (22 ) — — 30,946 (22 ) Total $ 296,652 $ (468 ) $ 127,404 $ (120 ) $ 424,056 $ (588 ) The Company invests in securities that are rated investment grade. The Company reviews the individual securities in its portfolio to determine whether a decline in a security's fair value below the amortized cost basis is other-than-temporary. The Company determined that as of December 31, 2019 , there were no investments in its portfolio that were other-than-temporarily impaired.

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Dec. 31, 2019
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): December 31, September 30, Cash and cash equivalents $ 735,457 $ 599,219 Restricted cash included in other assets, net 3,188 3,035 Total cash, cash equivalents and restricted cash $ 738,645 $ 602,254 Inventories Inventories consist of the following (in thousands): December 31, September 30, Finished goods $ 21,463 $ 22,441 Raw materials 10,918 11,960 $ 32,381 $ 34,401 Other Current Assets Other current assets consist of the following (in thousands): December 31, September 30, Contract assets $ 85,118 $ 79,407 Prepaid expenses 55,170 49,051 Capitalized contract acquisition costs 27,752 28,228 Other 20,164 26,188 $ 188,204 $ 182,874 Other Assets Other assets, net consist of the following (in thousands): December 31, September 30, Intangible assets $ 104,315 $ 108,903 Contract assets 50,128 53,085 Capitalized contract acquisition costs 30,401 31,218 Other 13,007 10,575 $ 197,851 $ 203,781 Accrued Liabilities Accrued liabilities consist of the following (in thousands): December 31, September 30, Payroll and benefits $ 110,446 $ 138,453 Operating lease liabilities, current 42,519 — Income and other tax accruals 39,503 31,801 Other 57,882 65,615 $ 250,350 $ 235,869 Other Long-term Liabilities Other long-term liabilities consist of the following (in thousands): December 31, September 30, Income taxes payable $ 44,520 $ 42,324 Deferred rent — 66,103 Other 18,091 23,426 $ 62,611 $ 131,853

Leases

Leases	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Leases	Leases During the first quarter of fiscal 2020, the Company adopted ASU 2016-02, Leases (Topic 842) (the “Leasing Standard”) using the transition method provided in ASU 2018-11, Leases (Topic 842): Targeted Improvements . The impact of adopting the Leasing Standard resulted in the recognition of right-of-use assets and lease liabilities of $304.8 million and $386.4 million , respectively. 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 has not yet determined whether the renewal option is likely to be exercised. 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 three months ended December 31, 2019 were as follows (in thousands): Three months ended Operating lease expense $ 11,318 Short-term lease expense 814 Variable lease expense 5,839 Total lease expense $ 17,971 Variable lease expense primarily consists of common area maintenance and parking expenses. The Company executed two sublease contracts that commenced during the first quarter of fiscal year 2020. Lease income payments are not due until the second fiscal quarter. Supplemental balance sheet information related to the Company's operating leases was as follows (in thousands, except lease term and discount rate): December 31, 2019 Operating lease right-of-use assets, net $ 303,435 Operating lease liabilities, current 1 42,519 Operating lease liabilities, long-term 342,303 Total operating lease liabilities $ 384,822 Weighted average remaining lease term (in years) 11.1 Weighted average discount rate 2.65 % (1) Current portion of operating lease liabilities is included in accrued liabilities on the Company's consolidated balance sheet. Maturities of lease liabilities as of December 31, 2019 were as follows (in thousands): Fiscal Years Ending September 30: Operating Lease Payments 2020 (remainder) $ 39,193 2021 51,202 2022 48,737 2023 36,259 2024 32,938 2025 28,436 Thereafter 215,966 Total lease payments 452,731 Less: imputed interest (67,909 ) Total lease liabilities $ 384,822 Operating lease liabilities above do not include sublease income. As of December 31, 2019, the Company expects to receive sublease income of approximately $5.6 million , which consists of $1.2 million to be received for the remainder of fiscal 2020 and $4.4 million to be received over the three fiscal years thereafter. As of December 31, 2019, the Company had no significant operating leases that were executed but not yet commenced. ASC 840 - Leases As a result of adopting the Leasing Standard, reporting periods beginning in the first quarter of fiscal 2020 are presented under the new standard while prior period amounts are not adjusted and continue to be reported in accordance with ASC 840 - Leases. Prior to the adoption of the Leasing Standard, future minimum operating lease payments, net of sublease income, were as follows as of September 30, 2019 (in thousands): Fiscal Year Gross Lease Payments Sublease Income Net Lease Payments 2020 $ 54,046 $ 683 $ 53,363 2021 50,712 1,051 49,661 2022 47,550 1,082 46,468 2023 36,514 368 36,146 2024 33,971 — 33,971 Thereafter 242,826 — 242,826 $ 465,619 $ 3,184 $ 462,435

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies 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 certain other employees, 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 generally 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. Accrued warranty costs as of December 31, 2019 and September 30, 2019 were not material. Commitments As of December 31, 2019 , the Company’s principal commitments consisted of obligations outstanding under operating leases. The Company leases its facilities under operating leases that expire at various dates through 2033. There have been no material changes in the Company's lease obligations compared to those discussed in Note 11 to its annual consolidated financial statements. The Company currently has arrangements with contract manufacturers and other suppliers for the manufacturing of its products. The arrangement with the primary contract manufacturer allows them to procure component inventory on the Company’s behalf based on a rolling production forecast provided by the Company. The Company is obligated to the purchase of component inventory that the contract manufacturer procures in accordance with the forecast, unless it gives notice of order cancellation in advance of applicable lead times. There have been no material changes in the Company's inventory purchase obligations compared to those discussed in Note 11 to its annual consolidated financial statements. Legal Proceedings

Income Taxes

Income Taxes	3 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our tax provision for interim periods is determined using an estimated annual effective tax rate, adjusted for discrete items in the related period. The effective tax rate was 22.8% and 20.8% for the three months ended December 31, 2019 and 2018, respectively. The increase in the effective tax rate for the three months ended December 31, 2019 as compared to the three months ended December 31, 2018 is primarily due to the tax impact from stock-based compensation. At December 31, 2019 , the Company had $44.1 million of unrecognized tax benefits that, if recognized, would affect the effective tax rate. It is anticipated that the Company’s existing liabilities for unrecognized tax benefits will change within the next twelve months due to audit settlements or the expiration of statutes of limitations. The Company does not expect these changes to be material to the consolidated financial statements. The Company recognizes interest and, if applicable, penalties for any uncertain tax positions as a component of income tax expense. 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, 2015. Major jurisdictions where there are wholly owned subsidiaries of F5 Networks, Inc. which require income tax filings include the United Kingdom, Japan, Singapore, Australia, and Israel. The earliest periods open for review by local taxing authorities are fiscal years 2018 for the United Kingdom, 2014 for Japan, 2015 for Singapore, 2015 for Australia, and 2013 for Israel. The Company is currently under audit by various states for fiscal years 2014 through 2017 and by Israel for fiscal years 2013 to 2017. Within the next four fiscal quarters, the statute of limitations will begin to close on the fiscal year 2016 federal income tax return, fiscal years 2015 and 2016 state income tax returns, and fiscal years 2013 to 2018 foreign income tax returns.

Net Income Per Share

Net Income Per Share	3 Months Ended
	Dec. 31, 2019
Net Income Per Share [Abstract]
Earnings Per Share	Net Income Per Share Basic 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 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): Three months ended 2019 2018 Numerator Net income $ 98,527 $ 130,905 Denominator Weighted average shares outstanding — basic 60,649 60,216 Dilutive effect of common shares from stock options and restricted stock units 166 429 Weighted average shares outstanding — diluted 60,815 60,645 Basic net income per share $ 1.62 $ 2.17 Diluted net income per share $ 1.62 $ 2.16 Anti-dilutive stock-based awards excluded from the calculations of diluted earnings per share were immaterial for the three months ended December 31, 2019 and 2018.

Segment Information

Segment Information	3 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Reporting Disclosure	Segment Information 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: the development, marketing and sale of application services that optimize the security, performance and availability of network applications, servers and storage systems. 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 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): Three months ended 2019 2018 Americas: United States $ 275,499 $ 264,751 Other 26,063 26,893 Total Americas 301,562 291,644 EMEA 155,952 148,984 Asia Pacific 111,791 103,142 $ 569,305 $ 543,770 The following distributors of the Company's products accounted for more than 10% of total net revenue: Three months ended 2019 2018 Ingram Micro, Inc. 16.5 % 16.8 % Westcon Group, Inc. 11.0 % 11.3 % Arrow ECS 10.1 % 10.9 % The Company tracks assets by physical location. Long-lived assets consist of property and equipment, net, and are shown below (in thousands): December 31, September 30, United States $ 198,595 $ 194,176 EMEA 14,678 13,451 Other countries 16,527 15,799 $ 229,800 $ 223,426

Restructuring Charges

Restructuring Charges	3 Months Ended
	Dec. 31, 2019
Restructuring Charges [Abstract]
Restructuring Charges	Restructuring Charges In December 2019, the Company initiated a restructuring plan to match strategic and financial objectives and optimize resources for long term growth, including a reduction in force program affecting approximately 75 employees. The Company recorded a restructuring charge of $7.8 million in the first quarter of fiscal 2020. The Company does not expect to record any significant future charges related to the restructuring plan. During the quarter ended December 31, 2019, the following activity was recorded (in thousands): Employee Severance, Benefits and Related Costs Accrued expenses, October 1, 2019 $ — Restructuring charges 7,800 Cash payments (5,282 ) Non-cash items — Accrued expenses, December 31, 2019 $ 2,518

Subsequent Event

Subsequent Event	3 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Acquisition of Shape Security, Inc. On December 19, 2019, the Company entered into a Merger Agreement (the “Merger Agreement”) with Shape Security, Inc. ("Shape"), a provider of fraud and abuse prevention solutions. The transaction closed on January 24, 2020 with Shape becoming a wholly-owned subsidiary of F5. Pursuant to the Merger Agreement, at the effective time of the Merger, the capital stock of Shape and the vested outstanding and unexercised stock options in Shape were cancelled and converted to the right to receive approximately $1.0 billion in cash, subject to certain adjustments and conditions set forth in the Merger Agreement, and the unvested stock options and restricted stock units in Shape held by continuing employees of Shape were assumed by F5, on the terms and conditions set forth in the Merger Agreement. During the first quarter of 2020, the Company incurred approximately $4.0 million of acquisition and integration related expenses associated with the Shape acquisition, which is included within General and Administrative operating expenses in our Consolidated Income Statements. As a result of limited access to Shape information required to prepare initial accounting, together with the limited time since the acquisition date and the effort required to conform the financial statements to the Company's practices and policies, the initial accounting for the business combination is incomplete at the time of this filing. As a result, the Company is unable to provide the amounts recognized as of the acquisition date for the major classes of assets acquired and liabilities assumed, pre-acquisition contingencies and goodwill. Also, the Company is unable to provide pro forma revenues and earnings of the combined entity. This information will be included in the Company's Quarterly Report on Form 10-Q for the quarter ended March 31, 2020. 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 matures on January 24, 2023 with quarterly installments (commencing with the first full fiscal quarter ended after January 24, 2020) equal to 1.25% of the original principal amount of the Term Loan Facility. The remaining outstanding principal of borrowings under the Term Loan Facility is due upon maturity on January 24, 2023. Borrowings under the Term Loan Facility may be voluntarily prepaid, in whole or in part, without penalty or premium. Borrowings repaid or prepaid under the Term Loan Facility may not be reborrowed. Borrowings under the Term Loan Facility bear 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 our leverage ratio, or (b) an alternate base rate determined in accordance with the Term Credit Agreement, plus an applicable margin of 0.125% to 0.750% depending on the Company’s leverage ratio. Interest on the outstanding principal of borrowings is currently due monthly in arrears. As of January 24, 2020, the margin for LIBOR-based loans was 1.125% and the margin for alternate base rate loans was 0.125% . Among certain affirmative and negative covenants provided in the Term Credit Agreement, there is a financial covenant that requires the Company to maintain a leverage ratio, calculated as of the last day of each fiscal quarter, of consolidated total indebtedness to consolidated EBITDA. The proceeds from the Term Loan Facility were used to (i) finance, in part, the acquisition of Shape and (ii) to pay fees and expenses incurred in connection with the acquisition of Shape and the related transactions. As of February 5, 2020, there was $400.0 million outstanding under the Term Loan Facility. 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 . The Revolving Credit Facility matures on January 31, 2025. The remaining outstanding principal of borrowings under the Revolving Credit Facility is due upon maturity on January 31, 2025. The Company has the option to request up to two extensions of the maturity date in each case for an additional period of one year. Borrowings under the Revolving Credit Facility bear 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 our 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 our leverage ratio. The Revolving Credit Agreement also requires payment of a commitment fee calculated at a rate per annum of 0.125% to 0.300%

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Description of Business	Description of Business F5 Networks, Inc. (the “Company”) is a leading provider of multi-cloud application services 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, installation, maintenance, and other technical support services.
Basis of Presentation	Basis of Presentation The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. In the opinion of management, the unaudited consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary for their fair statement in conformity with accounting principles generally accepted in the United States of America. Certain information and footnote disclosures normally included in annual financial statements have been condensed or omitted in accordance with the rules and regulations of the Securities and Exchange Commission. The information included in this Form 10-Q should be read in conjunction with Management’s Discussion and Analysis of Financial Condition and Results of Operations and financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2019 . Certain prior year amounts have been reclassified to conform to the current year presentation in the Consolidated Statements of Cash Flows. The reclassified amounts are considered immaterial and there was no change to total cash from operating, investing or financing activities as a result. There have been no material changes to the Company's significant accounting policies as of and for the three months ended December 31, 2019 , except for the accounting policy for leases that was updated as a result of adopting Accounting Standards Update 2016-02, Leases (Topic 842) (ASU 2016-02) and related standards. For more information, refer to the "Recently Adopted Accounting Standards" section of Note 1 and Note 7 - Leases.
Recent Accounting Pronouncements	Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (ASU 2016-02), which requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a corresponding lease liability for all leases with terms greater than twelve months. The Company’s leases consist primarily of operating leases for its offices and lab spaces. The Company does not have finance leases. The guidance also requires qualitative and quantitative disclosures designed to assess the amount, timing and uncertainty of cash flows arising from leases. The Company adopted this standard on October 1, 2019 on a modified retrospective basis by applying the new standard to its lease portfolio as of October 1, 2019, while continuing to apply legacy guidance in the comparative periods. The adoption of this standard had no impact on the consolidated income statements and consolidated statements of cash flows. Refer to Note 7 - Leases for further discussion. Upon adoption of the standard, the Company elected the package of three expedients for existing and expired contracts to not reassess: the existence of additional leases, lease classification, or the treatment of initial direct costs. The Company also applies the short-term lease exemption for leases with an original expected term of 12 months or less and expenses such leases month-to-month and does not record a right-of-use asset or lease liability. Short-term lease activity under the exception is not significant. Additionally, the Company does not separate lease and non-lease components in the allocation of minimum lease payments for its office space and equipment leases, as such separation is not significant. The Company includes in minimum lease payments, fixed and variable payments based on a rate or index, but excludes variable payments based on satisfying future benchmarks or actual future costs incurred; such amounts are expensed as incurred. To calculate the net present value, the Company applied an incremental borrowing rate. This incremental borrowing rate is determined using a portfolio approach based on the rate of interest the Company would pay to borrow an amount equal to the lease payments on a collateralized basis over a similar term . Renewal options to extend lease terms are excluded from the minimum lease term at lease commencement. Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not anticipate that the adoption of this standard will have a material impact on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) (ASU 2018-15), which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software, and hosting arrangements that include an internal use software license. The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this update. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not anticipate that the adoption of this standard will have a material impact on its consolidated financial statements.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	3 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Capitalized Contract Cost	The table below shows significant movements in capitalized contract acquisition costs (current and noncurrent) for the three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 59,446 Additional capitalized contract acquisition costs deferred 7,412 Amortization of capitalized contract acquisition costs (8,705 ) Balance, December 31, 2019 $ 58,153
Contract with Customer, Asset and Liability	The table below shows significant movements in the deferred revenue balances (current and noncurrent) for the three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 1,198,116 Amounts billed but not recognized as revenues 346,132 Revenues recognized related to the opening balance of deferred revenue (306,275 ) Balance, December 31, 2019 $ 1,237,973 The table below shows significant movements in contract assets (current and noncurrent) for the three months ended December 31, 2019 (in thousands): Balance, September 30, 2019 $ 132,492 Revenue recognized during period but not yet billed 3,407 Contract asset net additions 12,930 Contract assets reclassified to accounts receivable (13,584 ) Balance, December 31, 2019 $ 135,245

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The purchase price allocation is as follows (in thousands): Assets acquired Cash and cash equivalents $ 29,911 Fair value of tangible assets: Accounts receivable 7,306 Other current assets 4,214 Property and equipment, net 1,822 Deferred tax assets 10,357 Intangible assets 89,300 Goodwill 509,414 Total assets acquired $ 652,324 Liabilities assumed Accounts payable $ (1,081 ) Deferred revenue (4,000 ) Other liabilities (4,035 ) Total liabilities assumed $ (9,116 ) Net assets acquired $ 643,208
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	The allocation of the purchase price and the estimated useful lives associated with certain assets is as follows (in thousands): Estimated Amount Useful Life Net tangible assets $ 44,494 — Identifiable intangible assets: Developed technologies 62,500 7 years Customer relationships 12,000 15 years Trade name 14,500 7 years Non-competition agreements 300 2 years Goodwill 509,414 — Total purchase price $ 643,208

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Dec. 31, 2019
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 December 31, 2019 , were as follows (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at December 31, Cash equivalents $ 249,178 $ 42,387 $ — $ 291,565 Short-term investments Available-for-sale securities — certificates of deposits — 991 — 991 Available-for-sale securities — corporate bonds and notes — 264,425 — 264,425 Available-for-sale securities — municipal bonds and notes — 9,190 — 9,190 Available-for-sale securities — U.S. government securities — 131,808 — 131,808 Available-for-sale securities — U.S. government agency securities — 20,347 — 20,347 Long-term investments Available-for-sale securities — corporate bonds and notes — 274,477 — 274,477 Available-for-sale securities — U.S. government securities — 7,559 — 7,559 Available-for-sale securities — U.S. government agency securities — 30,008 — 30,008 Total $ 249,178 $ 781,192 $ — $ 1,030,370 The Company’s financial assets measured at fair value on a recurring basis subject to the disclosure requirements at September 30, 2019 , were as follows (in thousands): Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at September 30, 2019 Cash equivalents $ 140,238 $ 153,404 $ — $ 293,642 Short-term investments Available-for-sale securities — certificates of deposits — 249 — 249 Available-for-sale securities — corporate bonds and notes — 259,547 — 259,547 Available-for-sale securities — municipal bonds and notes — 12,129 — 12,129 Available-for-sale securities — U.S. government securities — 78,992 — 78,992 Available-for-sale securities — U.S. government agency securities — 22,146 — 22,146 Long-term investments Available-for-sale securities — corporate bonds and notes — 298,916 — 298,916 Available-for-sale securities — municipal bonds and notes — 2,524 — 2,524 Available-for-sale securities — U.S. government securities — 5,515 — 5,515 Available-for-sale securities — U.S. government agency securities — 51,447 — 51,447 Total $ 140,238 $ 884,869 $ — $ 1,025,107

Short-Term and Long-Term Inve_2

Short-Term and Long-Term Investments (Tables)	3 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Short-Term and Long-Term Investments	Short-term investments consist of the following (in thousands): December 31, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Certificates of deposits $ 991 $ — $ — $ 991 Corporate bonds and notes 264,006 463 (44 ) 264,425 Municipal bonds and notes 9,188 5 (3 ) 9,190 U.S. government securities 131,784 42 (18 ) 131,808 U.S. government agency securities 20,335 12 — 20,347 $ 426,304 $ 522 $ (65 ) $ 426,761 September 30, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Certificates of deposits $ 249 $ — $ — $ 249 Corporate bonds and notes 259,242 402 (97 ) 259,547 Municipal bonds and notes 12,128 6 (5 ) 12,129 U.S. government securities 78,988 18 (14 ) 78,992 U.S. government agency securities 22,138 9 (1 ) 22,146 $ 372,745 $ 435 $ (117 ) $ 373,063 Long-term investments consist of the following (in thousands): December 31, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Corporate bonds and notes $ 274,383 $ 267 $ (173 ) $ 274,477 U.S. government securities 7,558 5 (4 ) 7,559 U.S. government agency securities 30,035 — (27 ) 30,008 $ 311,976 $ 272 $ (204 ) $ 312,044 September 30, 2019 Cost or Cost Gross Gains Gross Losses Fair Value Corporate bonds and notes $ 298,888 $ 469 $ (441 ) $ 298,916 Municipal bonds and notes 2,528 2 (6 ) 2,524 U.S. government securities 5,515 3 (3 ) 5,515 U.S. government agency securities 51,463 5 (21 ) 51,447 $ 358,394 $ 479 $ (471 ) $ 358,402
Schedule of Investments That Have Been in a Continuous Unrealized Loss Position	The following table summarizes investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for more than 12 months as of December 31, 2019 (in thousands): Less Than 12 Months 12 Months or Greater Total December 31, 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate bonds and notes $ 171,910 $ (180 ) $ 62,543 $ (37 ) $ 234,453 $ (217 ) Municipal bonds and notes 1,421 — 2,530 (3 ) 3,951 (3 ) U.S. government securities 79,687 (22 ) — — 79,687 (22 ) U.S. government agency securities 31,119 (27 ) — — 31,119 (27 ) Total $ 284,137 $ (229 ) $ 65,073 $ (40 ) $ 349,210 $ (269 ) The following table summarizes investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for more than 12 months as of September 30, 2019 (in thousands): Less Than 12 Months 12 Months or Greater Total September 30, 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate bonds and notes $ 237,747 $ (434 ) $ 109,613 $ (104 ) $ 347,360 $ (538 ) Municipal bonds and notes 864 — 7,800 (11 ) 8,664 (11 ) U.S. government securities 27,095 (12 ) 9,991 (5 ) 37,086 (17 ) U.S. government agency securities 30,946 (22 ) — — 30,946 (22 ) Total $ 296,652 $ (468 ) $ 127,404 $ (120 ) $ 424,056 $ (588 )

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Dec. 31, 2019
Balance Sheet Details [Abstract]
Cash and Cash Equivalents	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): December 31, September 30, Cash and cash equivalents $ 735,457 $ 599,219 Restricted cash included in other assets, net 3,188 3,035 Total cash, cash equivalents and restricted cash $ 738,645 $ 602,254
Inventories	Inventories consist of the following (in thousands): December 31, September 30, Finished goods $ 21,463 $ 22,441 Raw materials 10,918 11,960 $ 32,381 $ 34,401
Other Current Assets	Other current assets consist of the following (in thousands): December 31, September 30, Contract assets $ 85,118 $ 79,407 Prepaid expenses 55,170 49,051 Capitalized contract acquisition costs 27,752 28,228 Other 20,164 26,188 $ 188,204 $ 182,874
Other Assets, Noncurrent	Other assets, net consist of the following (in thousands): December 31, September 30, Intangible assets $ 104,315 $ 108,903 Contract assets 50,128 53,085 Capitalized contract acquisition costs 30,401 31,218 Other 13,007 10,575 $ 197,851 $ 203,781
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): December 31, September 30, Payroll and benefits $ 110,446 $ 138,453 Operating lease liabilities, current 42,519 — Income and other tax accruals 39,503 31,801 Other 57,882 65,615 $ 250,350 $ 235,869
Noncurrent Liabilities	Other long-term liabilities consist of the following (in thousands): December 31, September 30, Income taxes payable $ 44,520 $ 42,324 Deferred rent — 66,103 Other 18,091 23,426 $ 62,611 $ 131,853

Leases (Tables)

Leases (Tables)	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease, Cost	The components of the Company's operating lease expenses for the three months ended December 31, 2019 were as follows (in thousands): Three months ended Operating lease expense $ 11,318 Short-term lease expense 814 Variable lease expense 5,839 Total lease expense $ 17,971
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): December 31, 2019 Operating lease right-of-use assets, net $ 303,435 Operating lease liabilities, current 1 42,519 Operating lease liabilities, long-term 342,303 Total operating lease liabilities $ 384,822 Weighted average remaining lease term (in years) 11.1 Weighted average discount rate 2.65 % (1) Current portion of operating lease liabilities is included in accrued liabilities on the Company's consolidated balance sheet.
Lessee, Operating Lease, Liability, Maturity	Maturities of lease liabilities as of December 31, 2019 were as follows (in thousands): Fiscal Years Ending September 30: Operating Lease Payments 2020 (remainder) $ 39,193 2021 51,202 2022 48,737 2023 36,259 2024 32,938 2025 28,436 Thereafter 215,966 Total lease payments 452,731 Less: imputed interest (67,909 ) Total lease liabilities $ 384,822
Future Minimum Rental Payments for Operating Leases	Prior to the adoption of the Leasing Standard, future minimum operating lease payments, net of sublease income, were as follows as of September 30, 2019 (in thousands): Fiscal Year Gross Lease Payments Sublease Income Net Lease Payments 2020 $ 54,046 $ 683 $ 53,363 2021 50,712 1,051 49,661 2022 47,550 1,082 46,468 2023 36,514 368 36,146 2024 33,971 — 33,971 Thereafter 242,826 — 242,826 $ 465,619 $ 3,184 $ 462,435

Net Income Per Share (Tables)

Net Income Per Share (Tables)	3 Months Ended
	Dec. 31, 2019
Net Income Per Share [Abstract]
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): Three months ended 2019 2018 Numerator Net income $ 98,527 $ 130,905 Denominator Weighted average shares outstanding — basic 60,649 60,216 Dilutive effect of common shares from stock options and restricted stock units 166 429 Weighted average shares outstanding — diluted 60,815 60,645 Basic net income per share $ 1.62 $ 2.17 Diluted net income per share $ 1.62 $ 2.16

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule of Revenues by Geographic Region	The following presents revenues by geographic region (in thousands): Three months ended 2019 2018 Americas: United States $ 275,499 $ 264,751 Other 26,063 26,893 Total Americas 301,562 291,644 EMEA 155,952 148,984 Asia Pacific 111,791 103,142 $ 569,305 $ 543,770
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: Three months ended 2019 2018 Ingram Micro, Inc. 16.5 % 16.8 % Westcon Group, Inc. 11.0 % 11.3 % Arrow ECS 10.1 % 10.9 %
Long-lived Assets by Geographic Areas	The Company tracks assets by physical location. Long-lived assets consist of property and equipment, net, and are shown below (in thousands): December 31, September 30, United States $ 198,595 $ 194,176 EMEA 14,678 13,451 Other countries 16,527 15,799 $ 229,800 $ 223,426

Restructuring Charges (Tables)

Restructuring Charges (Tables)	3 Months Ended
	Dec. 31, 2019
Restructuring Charges [Abstract]
Restructuring and Related Costs	During the quarter ended December 31, 2019, the following activity was recorded (in thousands): Employee Severance, Benefits and Related Costs Accrued expenses, October 1, 2019 $ — Restructuring charges 7,800 Cash payments (5,282 ) Non-cash items — Accrued expenses, December 31, 2019 $ 2,518

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Capitalized contract acquisition costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Changes In Capitalized Contract Cost [Roll Forward]
Beginning Balance	$ 59,446
Additional capitalized contract acquisition costs deferred	7,412
Amortization of capitalized contract acquisition costs	(8,705)	$ (7,300)
Ending Balance	$ 58,153

Revenue from Contracts with C_4

Revenue from Contracts with Customers Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Amortization of capitalized contract acquisition costs	$ 8,705	$ 7,300

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)
Change in Contract with Customer, Asset [Roll Forward]
Beginning Balance	$ 132,492
Revenue recognized during period but not yet billed	3,407
Contract asset net additions	12,930
Contract assets reclassified to accounts receivable	13,584
Ending Balance	135,245
Change in Contract with Customer, Liability [Roll Forward]
Beginning Balance	1,198,116
Amounts billed but not recognized as revenues	346,132
Revenues recognized related to the opening balance of deferred revenue	(306,275)
Ending Balance	$ 1,237,973

Revenue from Contracts with C_6

Revenue from Contracts with Customers Remaining Performance Obligations (Details) $ in Billions	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 1.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, percentage	18.70%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months

Business Combinations (Details)

Business Combinations (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Fair value of tangible assets:
Goodwill	$ 1,065,379	$ 1,065,379
F5 Networks Acquisition of Nginx
Assets acquired
Cash and cash equivalents	29,911
Fair value of tangible assets:
Accounts receivable	7,306
Other current assets	4,214
Property and equipment, net	1,822
Deferred tax assets	10,357
Intangible assets	89,300
Goodwill	509,414
Total assets acquired	652,324
Liabilities assumed
Accounts payable	(1,081)
Deferred revenue	(4,000)
Other liabilities	(4,035)
Total liabilities assumed	(9,116)
Net assets acquired	643,208
F5 Networks Acquisition of Nginx | Developed Technology Rights
Fair value of tangible assets:
Intangible assets	62,500
F5 Networks Acquisition of Nginx | Customer Relationships
Fair value of tangible assets:
Intangible assets	12,000
F5 Networks Acquisition of Nginx | Trade Names
Fair value of tangible assets:
Intangible assets	14,500
F5 Networks Acquisition of Nginx | Non-competition Agreements
Fair value of tangible assets:
Intangible assets	$ 300

Business Combinations Allocatio

Business Combinations Allocation of Purchase Price and Estimated Useful Life (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Identifiable intangible assets:
Goodwill	$ 1,065,379	$ 1,065,379
F5 Networks Acquisition of Nginx
Acquired Finite-Lived Intangible Assets [Line Items]
Net tangible assets	44,494
Identifiable intangible assets:
Identifiable intangible assets amounts	$ 89,300
Identifiable intangible assets useful life	8 years 1 month 6 days
Goodwill	$ 509,414
Total purchase price	643,208
F5 Networks Acquisition of Nginx | Developed Technology Rights
Identifiable intangible assets:
Identifiable intangible assets amounts	$ 62,500
Identifiable intangible assets useful life	7 years
F5 Networks Acquisition of Nginx | Customer Relationships
Identifiable intangible assets:
Identifiable intangible assets amounts	$ 12,000
Identifiable intangible assets useful life	15 years
F5 Networks Acquisition of Nginx | Trade Names
Identifiable intangible assets:
Identifiable intangible assets amounts	$ 14,500
Identifiable intangible assets useful life	7 years
F5 Networks Acquisition of Nginx | Non-competition Agreements
Identifiable intangible assets:
Identifiable intangible assets amounts	$ 300
Identifiable intangible assets useful life	2 years

Business Combinations Narrative

Business Combinations Narrative (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)
Business Acquisition [Line Items]
Transaction costs	$ 4,000
F5 Networks Acquisition of Nginx
Business Acquisition [Line Items]
Identifiable intangible assets useful life	8 years 1 month 6 days
Tax deductible goodwill	$ 450,700
Transaction costs	19,000
Total purchase price	643,208
F5 Networks Acquisition of Nginx | General and Administrative Expense
Business Acquisition [Line Items]
Transaction costs	$ 1,000

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Financial Assets Measured at Fair Value on a Recurring Basis) (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Cash equivalents, fair value	$ 291,565	$ 293,642
Investments, fair value	1,030,370	1,025,107
Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	991	249
Corporate Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	264,425	259,547
Debt Securities, Available-for-sale, Noncurrent	274,477	298,916
Municipal Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	9,190	12,129
Debt Securities, Available-for-sale, Noncurrent		2,524
U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	131,808	78,992
Debt Securities, Available-for-sale, Noncurrent	7,559	5,515
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	20,347	22,146
Debt Securities, Available-for-sale, Noncurrent	30,008	51,447
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Cash equivalents, fair value	249,178	140,238
Debt Securities, Available-for-sale, Noncurrent	0	0
Investments, fair value	249,178	140,238
Level 1 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 1 | Corporate Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 1 | Municipal Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 1 | U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 1 | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Cash equivalents, fair value	42,387	153,404
Investments, fair value	781,192	884,869
Level 2 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	991	249
Level 2 | Corporate Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	264,425	259,547
Debt Securities, Available-for-sale, Noncurrent	274,477	298,916
Level 2 | Municipal Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	9,190	12,129
Debt Securities, Available-for-sale, Noncurrent		2,524
Level 2 | U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	131,808	78,992
Debt Securities, Available-for-sale, Noncurrent	7,559	5,515
Level 2 | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	20,347	22,146
Debt Securities, Available-for-sale, Noncurrent	30,008	51,447
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Cash equivalents, fair value	0	0
Debt Securities, Available-for-sale, Noncurrent	0	0
Investments, fair value	0	0
Level 3 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 3 | Corporate Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 3 | Municipal Bonds and Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 3 | U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	0	0
Level 3 | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Current	$ 0	$ 0

Short-Term and Long-Term Inve_3

Short-Term and Long-Term Investments (Schedule of Short-Term and Long-Term Investments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Schedule of Investments [Line Items]
Interest income from investments	$ 5,600	$ 7,000
Short-Term Investments
Schedule of Investments [Line Items]
Cost or amortized cost	426,304		$ 372,745
Gross unrealized gains	522		435
Gross unrealized losses	(65)		(117)
Fair value	426,761		373,063
Short-Term Investments | Certificates of Deposit
Schedule of Investments [Line Items]
Cost or amortized cost	991		249
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Fair value	991		249
Short-Term Investments | Corporate Bonds and Notes
Schedule of Investments [Line Items]
Cost or amortized cost	264,006		259,242
Gross unrealized gains	463		402
Gross unrealized losses	(44)		(97)
Fair value	264,425		259,547
Short-Term Investments | Municipal Bonds and Notes
Schedule of Investments [Line Items]
Cost or amortized cost	9,188		12,128
Gross unrealized gains	5		6
Gross unrealized losses	(3)		(5)
Fair value	9,190		12,129
Short-Term Investments | U.S. Government Securities
Schedule of Investments [Line Items]
Cost or amortized cost	131,784		78,988
Gross unrealized gains	42		18
Gross unrealized losses	(18)		(14)
Fair value	131,808		78,992
Short-Term Investments | U.S. Government Agency Securities
Schedule of Investments [Line Items]
Cost or amortized cost	20,335		22,138
Gross unrealized gains	12		9
Gross unrealized losses	0		(1)
Fair value	20,347		22,146
Long-Term Investments
Schedule of Investments [Line Items]
Cost or amortized cost	311,976		358,394
Gross unrealized gains	272		479
Gross unrealized losses	(204)		(471)
Fair value	312,044		358,402
Long-Term Investments | Corporate Bonds and Notes
Schedule of Investments [Line Items]
Cost or amortized cost	274,383		298,888
Gross unrealized gains	267		469
Gross unrealized losses	(173)		(441)
Fair value	274,477		298,916
Long-Term Investments | Municipal Bonds and Notes
Schedule of Investments [Line Items]
Cost or amortized cost			2,528
Gross unrealized gains			2
Gross unrealized losses			(6)
Fair value			2,524
Long-Term Investments | U.S. Government Securities
Schedule of Investments [Line Items]
Cost or amortized cost	7,558		5,515
Gross unrealized gains	5		3
Gross unrealized losses	(4)		(3)
Fair value	7,559		5,515
Long-Term Investments | U.S. Government Agency Securities
Schedule of Investments [Line Items]
Cost or amortized cost	30,035		51,463
Gross unrealized gains	0		5
Gross unrealized losses	(27)		(21)
Fair value	$ 30,008		$ 51,447

Short-Term and Long-Term Inve_4

Short-Term and Long-Term Investments (Schedule of Investments That Have Been in a Continuous Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Fair Value
Less than 12 months	$ 284,137	$ 296,652
12 months or greater	65,073	127,404
Total	349,210	424,056
Gross Unrealized Losses
Less than 12 months	(229)	(468)
12 months or greater	(40)	(120)
Total	(269)	(588)
Corporate Bonds and Notes
Fair Value
Less than 12 months	171,910	237,747
12 months or greater	62,543	109,613
Total	234,453	347,360
Gross Unrealized Losses
Less than 12 months	(180)	(434)
12 months or greater	(37)	(104)
Total	(217)	(538)
Municipal Bonds and Notes
Fair Value
Less than 12 months	1,421	864
12 months or greater	2,530	7,800
Total	3,951	8,664
Gross Unrealized Losses
Less than 12 months	0	0
12 months or greater	(3)	(11)
Total	(3)	(11)
U.S. Government Securities
Fair Value
Less than 12 months	79,687	27,095
12 months or greater	0	9,991
Total	79,687	37,086
Gross Unrealized Losses
Less than 12 months	(22)	(12)
12 months or greater	0	(5)
Total	(22)	(17)
U.S. Government Agency Securities
Fair Value
Less than 12 months	31,119	30,946
12 months or greater	0	0
Total	31,119	30,946
Gross Unrealized Losses
Less than 12 months	(27)	(22)
12 months or greater	0	0
Total	$ (27)	$ (22)

Balance Sheet Details Cash and

Balance Sheet Details Cash and Cash Equivalent (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Balance Sheet Details [Abstract]
Cash and cash equivalents	$ 735,457	$ 599,219
Restricted cash included in other assets, net	3,188	3,035
Total cash, cash equivalents and restricted cash	$ 738,645	$ 602,254	$ 481,273	$ 425,894

Balance Sheet Details Inventori

Balance Sheet Details Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Balance Sheet Details [Abstract]
Finished goods	$ 21,463	$ 22,441
Raw materials	10,918	11,960
Inventories	$ 32,381	$ 34,401

Balance Sheet Details Other Cur

Balance Sheet Details Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Balance Sheet Details [Abstract]
Contract assets	$ 85,118	$ 79,407
Prepaid expenses	55,170	49,051
Capitalized contract acquisition costs	27,752	28,228
Other	20,164	26,188
Other Assets, Current	$ 188,204	$ 182,874

Balance Sheet Details Other Ass

Balance Sheet Details Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Balance Sheet Details [Abstract]
Intangible assets	$ 104,315	$ 108,903
Contract assets	50,128	53,085
Capitalized contract acquisition costs	30,401	31,218
Other	13,007	10,575
Other Assets, Noncurrent	$ 197,851	$ 203,781

Balance Sheet Details Accrued L

Balance Sheet Details Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Balance Sheet Details [Abstract]
Payroll and benefits	$ 110,446	$ 138,453
Operating lease liabilities, current	42,519	0
Income and other tax accruals	39,503	31,801
Other	57,882	65,615
Accrued Liabilities, Current	$ 250,350	$ 235,869

Balance Sheet Details Other Lon

Balance Sheet Details Other Long-term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Balance Sheet Details [Abstract]
Income taxes payable	$ 44,520	$ 42,324
Deferred rent	0	66,103
Other	18,091	23,426
Other long-term liabilities	$ 62,611	$ 131,853

Leases Lease (Details)

Leases Lease (Details) ft² in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)ft²	Sep. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 303,435	$ 0
Sublease Income	5,600
Sublease income payment remainder of fiscal year	1,200
Payment to be received in year two	4,400
Payment to be received in year three	4,400
Payment to be received in year four	$ 4,400
Office Building
Lessee, Lease, Description [Line Items]
Operating lease, number of square feet | ft²	515
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 304,800
Lease liabilities	$ 386,400

Leases Operating Lease Expense

Leases Operating Lease Expense (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease expense	$ 11,318
Short-term lease expense	814
Variable lease expense	5,839
Total lease expense	$ 17,971

Leases Supplemental Balance She

Leases Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 303,435	$ 0
Operating lease liabilities, current	(42,519)	0
Operating lease liabilities, long-term	(342,303)	$ 0
Total lease liabilities	$ 384,822
Weighted average remaining lease term (in years)	11 years 1 month 6 days
Weighted average discount rate	2.65%

Leases Maturities of Lease Liab

Leases Maturities of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020 (remainder)	$ 39,193
2021	51,202
2022	48,737
2023	36,259
2024	32,938
2025	28,436
Thereafter	215,966
Total lease payments	452,731
Less: imputed interest	(67,909)
Total lease liabilities	$ 384,822

Leases Operating Lease Future M

Leases Operating Lease Future MInimum ASC 840 (Details) $ in Thousands	Sep. 30, 2019USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2020	$ 54,046
2021	50,712
2022	47,550
2023	36,514
2024	33,971
Thereafter	242,826
Operating leases, future minimum payments due	465,619
Operating Leases, Future Minimum Payments Receivable [Abstract]
2020	683
2021	1,051
2022	1,082
2023	368
2024	0
Thereafter	0
Operating leases, future minimum payments receivable	3,184
Future Minimum Operating Net Lease Payments Fiscal Year Maturity [Abstract]
2020	53,363
2021	49,661
2022	46,468
2023	36,146
2024	33,971
Thereafter	242,826
Future minimum operating net lease payments	$ 462,435

Commitments And Contingencies (

Commitments And Contingencies (Details)	3 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Product warranty period	1 year

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Effective tax rate	22.80%	20.80%
Unrecognized tax benefit	$ 44.1

Net Income Per Share (Details)

Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator
Net income	$ 98,527	$ 130,905
Denominator
Weighted average shares outstanding — basic (shares)	60,649	60,216
Dilutive effect of common shares from stock options and restricted stock units	166	429
Weighted average shares outstanding — diluted (shares)	60,815	60,645
Basic net income per share (dollars per share)	$ 1.62	$ 2.17
Diluted net income per share (dollars per share)	$ 1.62	$ 2.16

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)segmentgeographic_region	Dec. 31, 2018USD ($)	Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Number of geographic regions | geographic_region	3
Net revenues	$ 569,305	$ 543,770
Long-lived assets	229,800		$ 223,426
United States
Segment Reporting Information [Line Items]
Net revenues	275,499	264,751
Long-lived assets	198,595		194,176
Other
Segment Reporting Information [Line Items]
Net revenues	26,063	26,893
Total Americas
Segment Reporting Information [Line Items]
Net revenues	301,562	291,644
EMEA
Segment Reporting Information [Line Items]
Net revenues	155,952	148,984
Long-lived assets	14,678		13,451
Asia Pacific
Segment Reporting Information [Line Items]
Net revenues	111,791	$ 103,142
Other countries
Segment Reporting Information [Line Items]
Long-lived assets	$ 16,527		$ 15,799
Ingram Micro, Inc. | Net Revenue | Geographic Concentration
Segment Reporting Information [Line Items]
Concentration risk percentage	16.50%	16.80%
Westcon Group, Inc. | Net Revenue | Geographic Concentration
Segment Reporting Information [Line Items]
Concentration risk percentage	11.00%	11.30%
Arrow ECS | Net Revenue | Geographic Concentration
Segment Reporting Information [Line Items]
Concentration risk percentage	10.10%	10.90%

Restructuring Charges Narrative

Restructuring Charges Narratives (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)employee	Dec. 31, 2018USD ($)
Restructuring Charges [Abstract]
Number of employees in reduction of force program | employee	75
Restructuring charges | $	$ 7,800	$ 0

Restructuring Charges (Details)

Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Accrued expenses (Beginning balance)	$ 0
Restructuring charges	7,800	$ 0
Cash payments	(5,282)
Non-cash items	0
Accrued expenses (Ending balance)	$ 2,518

Subsequent Event (Details)

Subsequent Event (Details) - USD ($)	Jan. 31, 2020	Jan. 24, 2020	Feb. 05, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Transaction costs				$ 4,000,000
Subsequent Event | Term Loan Facility
Subsequent Event [Line Items]
Aggregate principal amount		$ 400,000,000
Redemption percentage		1.25%
Outstanding line of credit balance			$ 400,000,000
Subsequent Event | Term Loan Facility | London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Interest rate at end of period		1.125%
Subsequent Event | Term Loan Facility | London Interbank Offered Rate (LIBOR) | Minimum
Subsequent Event [Line Items]
Interest rate		1.125%
Subsequent Event | Term Loan Facility | London Interbank Offered Rate (LIBOR) | Maximum
Subsequent Event [Line Items]
Interest rate		1.75%
Subsequent Event | Term Loan Facility | Alternate Base Rate
Subsequent Event [Line Items]
Interest rate at end of period		0.125%
Subsequent Event | Term Loan Facility | Alternate Base Rate | Minimum
Subsequent Event [Line Items]
Interest rate		0.125%
Subsequent Event | Term Loan Facility | Alternate Base Rate | Maximum
Subsequent Event [Line Items]
Interest rate		0.75%
Subsequent Event | Revolving Credit Facility
Subsequent Event [Line Items]
Aggregate principal amount	$ 350,000,000
Conditional increase in borrowing capacity	$ 150,000,000
Subsequent Event | Revolving Credit Facility | Minimum
Subsequent Event [Line Items]
Commitment fee percentage	0.125%
Subsequent Event | Revolving Credit Facility | Maximum
Subsequent Event [Line Items]
Commitment fee percentage	0.30%
Subsequent Event | Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum
Subsequent Event [Line Items]
Interest rate	1.125%
Subsequent Event | Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum
Subsequent Event [Line Items]
Interest rate	1.75%
Subsequent Event | Revolving Credit Facility | Alternate Base Rate | Minimum
Subsequent Event [Line Items]
Interest rate	0.125%
Subsequent Event | Revolving Credit Facility | Alternate Base Rate | Maximum
Subsequent Event [Line Items]
Interest rate	0.75%
Subsequent Event | Shape Security, Inc.
Subsequent Event [Line Items]
Total purchase price		$ 1,000,000,000

Uncategorized Items - ffiv10q12

Label	Element	Value
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 36,048,000
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 36,048,000