PTC (PTC) 10-Q 2 May 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Entity Registrant Name	PTC Inc.
Entity Central Index Key	857,005
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		115,386,106

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
ASSETS
Cash and cash equivalents	$ 299,776	$ 280,003
Short term marketable securities	22,797	18,408
Accounts receivable, net of allowance for doubtful accounts of $746 and $1,062 at March 31, 2018 and September 30, 2017, respectively	127,151	152,299
Prepaid expenses	62,094	49,913
Other current assets	137,342	165,933
Total current assets	649,160	666,556
Property and equipment, net	59,210	63,600
Goodwill	1,191,603	1,182,772
Acquired intangible assets, net	230,030	257,908
Long term marketable securities	32,467	31,907
Deferred tax assets	129,862	123,166
Other assets	36,482	34,475
Total assets	2,328,814	2,360,384
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	29,918	35,160
Accrued expenses and other current liabilities	73,631	80,761
Accrued compensation and benefits	82,544	110,957
Accrued income taxes	15,952	5,735
Deferred revenue	487,281	446,296
Total current liabilities	689,326	678,909
Long term debt	642,837	712,406
Deferred tax liabilities	5,704	17,880
Deferred revenue	10,496	12,611
Other liabilities	52,727	53,142
Total liabilities	1,401,090	1,474,948
Commitments and contingencies (Note 13)
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000 shares authorized; none issued	0	0
Common stock, $0.01 par value; 500,000 shares authorized; 116,338 and 115,333 shares issued and outstanding at March 31, 2018 and September 30, 2017, respectively	1,163	1,153
Additional paid-in capital	1,618,588	1,609,030
Accumulated deficit	(629,597)	(650,840)
Accumulated other comprehensive loss	(62,430)	(73,907)
Total stockholders’ equity	927,724	885,436
Total liabilities and stockholders’ equity	$ 2,328,814	$ 2,360,384

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Current assets:
Allowance for doubtful accounts	$ 746	$ 1,062
Stockholders’ equity:
Preferred stock, par value (in USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	116,338,000	115,333,000
Common stock, shares outstanding	116,338,000	115,333,000

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Revenues [Abstract]
Subscription	$ 112,931	$ 65,780	$ 212,939	$ 120,142
Support	126,683	141,718	257,880	293,196
Total recurring revenue	239,614	207,498	470,819	413,338
Perpetual license	22,839	27,372	56,824	61,751
Total subscription, support and license revenue	262,453	234,870	527,643	475,089
Professional services	45,430	45,170	86,884	91,278
Total revenue	307,883	280,040	614,527	566,367
Cost of revenue:
Cost of license and subscription revenue	23,119	20,555	47,495	40,685
Cost of support revenue	23,030	22,576	45,230	45,393
Total cost of software revenue	46,149	43,131	92,725	86,078
Cost of professional services revenue	37,482	38,699	73,864	77,867
Total cost of revenue	83,631	81,830	166,589	163,945
Gross margin	224,252	198,210	447,938	402,422
Operating expenses:
Sales and marketing	98,330	87,777	197,645	178,467
Research and development	62,194	57,710	126,163	115,624
General and administrative	33,353	36,800	68,357	73,495
Amortization of acquired intangible assets	7,895	7,946	15,716	16,013
Restructuring and other charges, net	114	464	219	6,749
Total operating expenses	201,886	190,697	408,100	390,348
Operating income	22,366	7,513	39,838	12,074
Interest expense	(10,379)	(11,725)	(20,426)	(22,040)
Interest income and other expense, net	(441)	3,156	(1,395)	2,407
Income (loss) before income taxes	11,546	(1,056)	18,017	(7,559)
Provision (benefit) for income taxes	3,624	48	(3,782)	2,686
Net income (loss)	$ 7,922	$ (1,104)	$ 21,799	$ (10,245)
Earnings(loss) per share—Basic (in USD per share)	$ 0.07	$ (0.01)	$ 0.19	$ (0.09)
Earnings(loss) per share—Diluted (in USD per share)	$ 0.07	$ (0.01)	$ 0.19	$ (0.09)
Weighted average shares outstanding—Basic (in shares)	116,241	115,709	115,986	115,498
Weighted average shares outstanding—Diluted (in shares)	117,905	115,709	117,780	115,498

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 7,922	$ (1,104)	$ 21,799	$ (10,245)
Other comprehensive income (loss), net of tax:
Unrealized hedge gain (loss) arising during the period, net of tax of $0.3 million and $0.1 million in the second quarter of 2018 and 2017, respectively, and $0.4 million and $0.4 million in the first six months of 2018 and 2017, respectively	(2,046)	(515)	(2,959)	2,522
Net hedge (gain) loss reclassified into earnings, net of tax of $0.2 million and $0.1 million in the second quarter of 2018 and 2017, respectively, and $0.3 million and $0.1 million in the first six months of 2018 and 2017, respectively	1,511	(496)	2,084	(852)
Unrealized gain (loss) on hedging instruments	(535)	(1,011)	(875)	1,670
Foreign currency translation adjustment, net of tax of $0 for each period	7,540	4,992	12,769	(13,660)
Unrealized gain (loss) on marketable securities, net of tax of $0 for each period	(267)	68	(446)	(71)
Amortization of net actuarial pension loss included in net income, net of tax of $0.2 million in both the second quarter of 2018 and 2017, and $0.3 million and $0.4 million in the first six months of 2018 and 2017, respectively	386	574	757	1,090
Change in unamortized pension loss during the period related to changes in foreign currency	(465)	(312)	(728)	1,378
Other comprehensive income (loss)	6,659	4,311	11,477	(9,593)
Comprehensive income (loss)	$ 14,581	$ 3,207	$ 33,276	$ (19,838)

Consolidated Statements Of Com6

Consolidated Statements Of Comprehensive Income (Loss) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Statement of Comprehensive Income [Abstract]
Unrealized hedge gain (loss) arising during the period, tax	$ 300,000	$ 100,000	$ 400,000	$ 400,000
Net hedge loss reclassified into earnings, tax	200,000	100,000	300,000	100,000
Foreign currency translation adjustment, tax	0	0	0	0
Unrealized gain (loss) marketable securities tax	0	0	0	0
Amortization of net actuarial pension loss included in net income, tax	$ 200,000	$ 200,000	$ 300,000	$ 400,000

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Cash flows from operating activities:
Net income (loss)	$ 21,799	$ (10,245)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation and amortization	42,727	42,683
Stock-based compensation	35,357	39,565
Non-cash portion of restructuring charges	0	260
Other non-cash items, net	189	479
Loss on disposal of fixed assets	22	0
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	32,027	15,373
Accounts payable and accrued expenses	(9,474)	11,183
Accrued compensation and benefits	(29,656)	(51,769)
Deferred revenue	59,027	27,457
Accrued income taxes	(14,134)	(14,680)
Other current assets and prepaid expenses	(7,540)	(11,424)
Other noncurrent assets and liabilities	5,931	(20,332)
Net cash provided by operating activities	136,275	28,550
Cash flows from investing activities:
Additions to property and equipment	(11,139)	(14,789)
Purchase of intangible asset	(3,000)	0
Purchases of short- and long-term marketable securities	(13,794)	(3,420)
Proceeds from maturities of short- and long-term marketable securities	8,240	4,700
Acquisitions of businesses, net of cash acquired	(3,000)	0
Proceeds from sales of investments	0	15,218
Net cash provided (used) by investing activities	(22,693)	1,709
Cash flows from financing activities:
Borrowings under credit facility	50,000	100,000
Repayments of borrowings under credit facility	(120,000)	(140,000)
Proceeds from issuance of common stock	7,472	3,978
Credit facility origination costs	0	(184)
Contingent consideration	(3,176)	(2,711)
Payments of withholding taxes in connection with vesting of stock-based awards	(33,942)	(19,166)
Net cash used in financing activities	(99,646)	(58,083)
Effect of exchange rate changes on cash and cash equivalents	5,837	(6,795)
Net increase (decrease) in cash and cash equivalents	19,773	(34,619)
Cash and cash equivalents, beginning of period	280,003	277,935
Cash and cash equivalents, end of period	$ 299,776	$ 243,316

Basis of Presentation

Basis of Presentation	6 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation General The accompanying unaudited condensed consolidated financial statements include the accounts of PTC Inc. and its wholly owned subsidiaries and have been prepared by management in accordance with accounting principles generally accepted in the United States of America and in accordance with the rules and regulations of the Securities and Exchange Commission regarding interim financial reporting. Accordingly, they do not include all the information and footnotes required by generally accepted accounting principles for complete financial statements. While we believe that the disclosures presented are adequate in order to make the information not misleading, these unaudited quarterly financial statements should be read in conjunction with our annual consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2017 . In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all adjustments, consisting only of those of a normal recurring nature, necessary for a fair statement of our financial position, results of operations and cash flows at the dates and for the periods indicated. The September 30, 2017 Consolidated Balance Sheet included herein is derived from our audited consolidated financial statements. Unless otherwise indicated, all references to a year mean our fiscal year, which ends on September 30. Our fiscal quarters end on a Saturday following a thirteen-week calendar, and may result in different quarter end dates year to year. The second quarter of 2018 ended on March 31, 2018 and the second quarter of 2017 ended on April 1, 2017 . The results of operations for the six months ended March 31, 2018 are not necessarily indicative of the results expected for the remainder of the fiscal year. Reclassifications Effective with the beginning of the third quarter of 2017, we are reporting cost of license and subscription revenue separately from cost of support revenue and are presenting cost of revenue in three categories: 1) cost of license and subscription revenue, 2) cost of support revenue, and 3) cost of professional services revenue. Cost of license and subscription includes the cost of perpetual and subscription licenses; cost of support includes the cost of supporting both perpetual and subscription licenses. Costs of revenue for previous periods in the accompanying Consolidated Statements of Operations are presented on a basis consistent with the current period presentation. Effective at the beginning of fiscal 2018, in accordance with the adoption of ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, excess tax benefits are now classified as an operating activity on the statement of cash flows rather than as a financing activity. The prior period excess tax benefits have been reclassified for comparability. Segments In fiscal 2017, we had three operating and reportable segments: (1) the Solutions Group, which included license, subscription, support and cloud services revenue for our core CAD, SLM and PLM products; (2) the IoT Group, which included license, subscription, support and cloud services revenue for our IoT, analytics and augmented reality solutions; and (3) Professional Services, which included consulting, implementation and training revenue. With a change in our organizational structure to streamline our operations, we merged our Solution Group segment with our IoT Group segment and revised the information that our chief executive officer, who is also our chief operating decision maker ("CODM"), regularly reviews for purposes of allocating resources and assessing performance. As a result, effective with the beginning of the first quarter of fiscal 2018, we changed our operating and reportable segments from three to two : (1) Software Products, which includes license, subscription and related support revenue (including updates and technical support) for all our products; and (2) Professional Services, which includes consulting, implementation and training services. Revenue and operating income in Note 10. Segment Information have been reclassified to conform to the current period presentation. Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements Stock Compensation In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. We adopted ASU No. 2016-09 in the first quarter of 2018. Effective with the adoption, stock-based compensation excess tax benefits or deficiencies are reflected in the Consolidated Statements of Operations as a component of the provision for income taxes when the awards vest or are settled. Previously they were recognized in equity. Upon adoption, under the modified retrospective transition method, we recognized the previously unrecognized excess tax benefits of $37.0 million as increases in deferred tax assets for tax loss carryovers and tax credits, $36.9 million of which were offset by an increase in our U.S. valuation allowance. Additionally, on our Consolidated Statements of Cash Flows excess tax benefits from stock-based awards will no longer be separately classified as a financing activity apart from other income tax, and will be presented as an operating activity. As a result of the adoption of ASU 2016-09, the Consolidated Statement of Cash Flows for the six months ended April 1, 2017 was adjusted as follows: a $0.1 million increase to net cash provided by operating activities and a $0.1 million decrease to net cash used in financing activities. Finally, we have elected to account for forfeitures as they occur, rather than estimate expected forfeitures, which resulted in a cumulative effect adjustment of $0.7 million to reduce retained earnings as of October 1, 2017. Pending Accounting Pronouncements Derivative Financial Instruments In August 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2017-12, "Derivatives and Hedging (Topic 815) Targeted Improvements to Accounting for Hedging Activities", which amends and simplifies existing guidance to allow companies to more accurately present the economic effects of risk management activities in the financial statements. The guidance is effective for annual reporting periods beginning after December 15, 2018 (our fiscal 2020) including interim reporting periods within those annual reporting periods and early adoption is permitted. We are currently evaluating the impact of the new guidance on our consolidated financial statements. Income Taxes In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). The purpose of ASU 2016-16 is to simplify the income tax accounting of an intra-entity transfer of an asset other than inventory and to record its effect when the transfer occurs. The guidance is effective for annual reporting periods beginning after December 15, 2017 (our fiscal 2019) including interim reporting periods within those annual reporting periods and early adoption is permitted. We are currently evaluating the impact of the new guidance on our consolidated financial statements. We expect to record a net deferred tax asset of approximately $77 million upon adoption, primarily relating to deductible amortization of intangible assets in Ireland. Post adoption, our effective tax rate will no longer include the benefit of this amortization, which is reflected in our effective tax rate reconciliation under the current guidance. Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which will replace the existing guidance in ASC 840, Leases. The updated standard aims to increase transparency and comparability among organizations by requiring lessees to recognize lease assets and lease liabilities on the balance sheet and to disclose important information about leasing arrangements. ASU 2016-02 is effective for annual periods beginning after December 15, 2018 (our fiscal 2020) and interim periods within those annual periods. Early adoption is permitted and modified retrospective application is required. We are currently evaluating the impact of the new guidance on our consolidated financial statements. Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 (ASU 2014-09). ASU 2014-09 supersedes nearly all existing revenue recognition guidance under U.S. GAAP. The FASB has also issued additional standards to provide clarification and implementation guidance on ASU 2014-09. The core principle of ASU 2014-09 is to recognize revenue when promised goods or services are transferred to a customer in an amount that reflects the consideration that is expected to be received for those goods or services. Under the new guidance, an entity is required to evaluate revenue recognition through a five-step process: (1) identifying a contract with a customer; (2) identifying the performance obligations in the contract; (3) determining the transaction price; (4) allocating the transaction price to the performance obligations in the contract; and (5) recognizing revenue when (or as) the entity satisfies a performance obligation. The standard also requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. In applying the principles of ASU 2014-09, it is possible more judgment and estimates may be required within the revenue recognition process than is required under existing U.S. GAAP, including identifying performance obligations, estimating the amount of variable consideration to include in the transaction price, and estimating the value of each performance obligation to allocate the total transaction price to each separate performance obligation. ASU 2014-09 is effective for us in our first quarter of fiscal 2019. Companies may adopt ASU 2014-09 using either the retrospective method, under which each prior reporting period is presented under ASU 2014-09, with the option to elect certain permitted practical expedients, or the modified retrospective method, under which a company adopts ASU 2014-09 from the beginning of the year of initial application with no restatement of comparative periods, with the cumulative effect of initially applying ASU 2014-09 recognized at the date of initial application, with certain additional required disclosures. We currently expect to adopt ASU 2014-09 using the modified retrospective method. While we are continuing to assess the impact of the new standard, we currently believe the most significant impact relates to accounting for our subscription arrangements that include term-based on-premise software licenses bundled with support. Under current GAAP, revenue attributable to these subscription licenses is recognized ratably over the term of the arrangement because VSOE does not exist for the undelivered support element as it is not sold separately. Under the new standard, the requirement to have VSOE for undelivered elements to enable the separation of revenue for the delivered software licenses is eliminated. Accordingly, under the new standard we will be required to recognize as revenue a portion of the subscription fee upon delivery of the software license. We currently expect revenue related to our perpetual licenses and related support contracts, professional services and cloud offerings to remain substantially unchanged. Due to the complexity of certain of our contracts, the actual revenue recognition treatment required under the new standard may be dependent on contract-specific terms and, therefore, may vary in some instances. Upon implementation of the new standard in fiscal 2019, we expect to make prospective revisions to contract terms with our customers that will result in shortening the initial, non-cancellable term of our multi-year subscriptions to one year for contracts entered into or renewed after October 1, 2018. This change will result in annual contractual periods for most of our software subscriptions, the license portion of which will be recognized at the beginning of each annual contract period upon delivery of the licenses and the support portion of which will be recognized ratably over the one-year contractual period. As a result, we anticipate one year of subscription revenue will be recognized for each contract each year; however, more of the revenue will be recognized in the quarter that the contract period begins and less will be recognized in the subsequent three quarters of the contract than under the current accounting rules. Under the modified retrospective method, we will evaluate each contract that is ongoing on the adoption date as if that contract had been accounted for under ASU 2014-09 from contract inception. Some license revenue related to subscription arrangements that would have been recognized in future periods under current GAAP will be recast under ASU 2014-09 as if the revenue had been recognized in prior periods. Under this transition method, we will not adjust historical reported revenue amounts. Instead, the revenue that would have been recognized under this method prior to the adoption date will be an adjustment to retained earnings and will not be recognized as revenue in future periods as previously expected. Because we expect that license revenue associated with subscription contracts will be recognized up front instead of over time under ASU 2014-09, we expect some portion of our deferred revenue to be adjusted to retained earnings upon adoption, which we expect will be a material amount. During the first year of adoption, we will record and disclose the amount of this retained earnings adjustment and intend to provide supplemental disclosure of how this revenue would have been recognized under the current rules. Another significant provision under ASU 2014-09 includes the capitalization and amortization of costs associated with obtaining a contract, such as sales commissions. Currently, we expense sales commissions in the period incurred. Under ASU 2014-09, direct and incremental costs to acquire a contract are capitalized and amortized using a systematic basis over the pattern of transfer of the goods and services to which the asset relates. While we are continuing to assess the impact of this provision of ASU 2014-09, we likely will be required to capitalize incremental costs such as commissions and amortize those costs over the period the capitalized assets are expected to contribute to future cash flows. Furthermore, we have made and will continue to make investments in systems and processes to enable timely and accurate reporting under the new standard. We currently expect that necessary operational and internal control structural changes will be implemented prior to the adoption date.

Deferred Revenue and Related Cu

Deferred Revenue and Related Customer Receivables	6 Months Ended
	Mar. 31, 2018
Deferred Revenue And Financing Receivables [Abstract]
Deferred Revenue and Related Customer Receivables	Deferred Revenue and Related Customer Receivables Deferred Revenue Deferred revenue primarily relates to software agreements billed to customers for which the subscription and support services have not yet been provided. The liability associated with performing these subscription and support services is included in deferred revenue and, if not yet paid, the related customer receivable is included in prepaid expenses and other current assets. Billed but uncollected support and subscription-related amounts included in other current assets at March 31, 2018 and September 30, 2017 were $132.1 million and $160.9 million , respectively.

Restructuring and Headquarters

Restructuring and Headquarters Relocation Charges	6 Months Ended
	Mar. 31, 2018
Restructuring [Abstract]
Restructuring and Headquarters Relocation Charges	Restructuring and Other Charges Restructuring Charges (Credits) In fiscal 2016, we initiated a plan to restructure our workforce and consolidate select facilities to reduce our cost structure and to realign our investments with what we believe to be our higher growth opportunities. The actions resulted in total restructuring charges of $84.7 million , primarily associated with termination benefits associated with approximately 800 employees. This restructuring plan is substantially complete. The following table summarizes restructuring accrual activity for the six months ended March 31, 2018 : Employee severance and related benefits Facility closures and related costs Total (in thousands) October 1, 2017 $ 1,736 $ 4,508 $ 6,244 Credit to operations, net (395 ) (339 ) (734 ) Cash disbursements (1,120 ) (806 ) (1,926 ) Foreign exchange impact 22 (47 ) (25 ) Accrual, March 31, 2018 $ 243 $ 3,316 $ 3,559 The following table summarizes restructuring accrual activity for the six months ended April 1, 2017 : Employee severance and related benefits Facility closures and related costs Total (in thousands) October 1, 2016 $ 35,177 $ 1,431 $ 36,608 Charges to operations, net 2,861 3,888 6,749 Cash disbursements (28,060 ) (880 ) (28,940 ) Other non-cash charges — (260 ) (260 ) Foreign exchange impact (1,002 ) (6 ) (1,008 ) Accrual, April 1, 2017 $ 8,976 $ 4,173 $ 13,149 Of the accrual for facility closures and related costs, as of March 31, 2018, $1.9 million is included in accrued expenses and other current liabilities and $1.4 million is included in other liabilities in the Consolidated Balance Sheets. The accrual for facility closures is net of assumed sublease income of $3.4 million . The accrual for employee severance and related benefits is included in accrued compensation and benefits in the Consolidated Balance Sheets. Other - Headquarters relocation charges Headquarters relocation charges represent accelerated depreciation expense recorded in anticipation of exiting our current headquarters facility. In 2019, we will be moving into a new worldwide headquarters in the Boston Seaport District, and we will be vacating our current headquarters space. Because our current headquarters lease will not expire until November 2022, we are seeking to sublease that space. If we are unable to sublease our current headquarters space for an amount at least equal to our rent obligations under the current headquarters lease, we will bear overlapping rent obligations for those premises and will be required to record a charge related to any rent shortfall. A charge for such shortfall will be recorded in the earlier of the period that we cease using the space (which will likely occur in the second quarter of our fiscal 2019) or the period we exit the lease contract. Additionally, we will incur other costs associated with the move which will be recorded as incurred. In the second quarter of 2018, we incurred an incremental $1.0 million of accelerated depreciation expense related to shortening the estimated useful lives of leasehold improvements in our current facility.

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Mar. 31, 2018
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Stock-Based Compensation	Stock-based Compensation We measure the cost of employee services received in exchange for restricted stock unit (RSU) awards based on the fair value of RSU awards on the date of grant. That cost is recognized over the period during which an employee is required to provide service in exchange for the award. Our equity incentive plan provides for grants of nonqualified and incentive stock options, common stock, restricted stock, RSUs and stock appreciation rights to employees, directors, officers and consultants. We award RSUs as the principal equity incentive awards, including performance-based awards that are earned based on achievement of performance criteria established by the Compensation Committee of our Board of Directors. Each RSU represents the contingent right to receive one share of our common stock. Beginning in the first quarter of 2018, we account for forfeitures as they occur, rather than estimate expected forfeitures. Our employee stock purchase plan (ESPP), initiated in the fourth quarter of 2016, allows eligible employees to contribute up to 10% of their base salary, up to a maximum of $25,000 per year and subject to other plan limitations, toward the purchase of our common stock at a discounted price. The purchase price of the shares on each purchase date is equal to 85% of the lower of the fair market value of our common stock on the first and last trading days of each offering period. The ESPP is qualified under Section 423 of the Internal Revenue Code. We estimate the fair value of each purchase right under the ESPP on the date of grant using the Black-Scholes option valuation model and use the straight-line attribution approach to record the expense over the six-month offering period. Restricted stock unit activity for the six months ended March 31, 2018 Shares Weighted Average Grant Date Fair Value (Per Share) (in thousands) Balance of outstanding restricted stock units October 1, 2017 3,487 $ 45.57 Granted (1) 1,355 $ 62.86 Vested (1,376 ) $ 44.42 Forfeited or not earned (471 ) $ 51.37 Balance of outstanding restricted stock units March 31, 2018 2,995 $ 53.03 _________________ (1) Restricted stock granted includes 184,000 shares from prior period TSR awards that were earned upon achievement of the performance criteria and vested in November 2018. Restricted Stock Units Grant Period Performance-based RSUs (1) Service-based RSUs (2) (Number of Units in thousands) First six months of 2018 461 710 _________________ (1) Substantially all the performance-based RSUs were granted to our executive officers. Approximately 189,000 shares are eligible to vest based upon annual performance measures, measured over a three -year period. RSUs not earned for a period may be earned in the third period. An additional 250,000 shares are eligible to vest based upon a 2018 performance measure. To the extent earned, those performance-based RSUs will vest in three substantially equal installments on November 15, 2018, November 15, 2019 and November 15, 2020, or the date the Compensation Committee determines the extent to which the applicable performance criteria have been achieved for each performance period. (2) The service-based RSUs were granted to employees, our executive officers and our directors. Substantially all service-based RSUs will vest in three substantially equal annual installments on or about the anniversary of the date of grant. Compensation expense recorded for our stock-based awards was classified in our Consolidated Statements of Operations as follows: Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Cost of license and subscription revenue $ 408 $ 314 $ 821 $ 607 Cost of support revenue 690 1,355 1,498 2,499 Cost of professional services revenue 1,669 1,539 3,375 2,995 Sales and marketing 5,038 4,130 9,917 7,751 Research and development 3,383 3,951 6,343 6,948 General and administrative 5,838 10,288 13,403 18,765 Total stock-based compensation expense $ 17,026 $ 21,577 $ 35,357 $ 39,565 Stock-based compensation expense includes $1.0 million and $2.1 million in the second quarter and first six months of 2018, respectively, and $0.7 million and $1.3 million in the second quarter and first six months of 2017, respectively, related to the ESPP.

Earnings per Share (EPS) and Co

Earnings per Share (EPS) and Common Stock	6 Months Ended
	Mar. 31, 2018
Earnings Per Share and Common Stock
Earnings(loss) per Share (EPS) and Common Stock	Earnings per Share (EPS) and Common Stock EPS Basic EPS is calculated by dividing net income by the weighted average number of shares outstanding during the period. Diluted EPS is calculated by dividing net income by the weighted average number of shares outstanding plus the dilutive effect, if any, of outstanding RSUs using the treasury stock method. The calculation of the dilutive effect of outstanding equity awards under the treasury stock method includes consideration of unrecognized compensation expense as additional proceeds. Three months ended Six months ended Calculation of Basic and Diluted EPS March 31, April 1, March 31, April 1, (in thousands, except per share data) Net income (loss) $ 7,922 $ (1,104 ) $ 21,799 $ (10,245 ) Weighted average shares outstanding—Basic 116,241 115,709 115,986 115,498 Dilutive effect of restricted stock units 1,664 — 1,794 — Weighted average shares outstanding—Diluted 117,905 115,709 117,780 115,498 Earnings (loss) per share—Basic $ 0.07 $ (0.01 ) $ 0.19 $ (0.09 ) Earnings (loss) per share—Diluted $ 0.07 $ (0.01 ) $ 0.19 $ (0.09 ) There were no antidilutive shares for the six months ended March 31, 2018 . Total antidilutive shares were 1.8 million for the six months ended April 1, 2017 . For the six months ended April 1, 2017 the diluted net loss per share is the same as the basic net loss per share as the effects of all our potential common stock equivalents are antidilutive, because we reported a loss for the period. Common Stock Repurchases Our Articles of Organization authorize us to issue up to 500 million shares of our common stock. Our Board of Directors periodically authorizes the repurchase of shares of our common stock. Our Board of Directors has authorized us to repurchase up to $500 million of our common stock from October 1, 2017 through September 30, 2020. We did not repurchase any shares in the second quarter and first six months of either 2018 or 2017. As described in Note 14 - Subsequent Events , in the third quarter of fiscal 2018 we entered into a $100 million accelerated share repurchase agreement. All shares of our common stock repurchased are automatically restored to the status of authorized and unissued.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets In 2017, we had three operating and reportable segments: (1) Solutions Group, (2) IoT Group and (3) Professional Services. Effective with the beginning of the first quarter of 2018, we changed our operating and reportable segments from three to two : (1) Software Products and (2) Professional Services. We assess goodwill for impairment at the reporting unit level. Our reporting units are determined based on the components of our operating segments that constitute a business for which discrete financial information is available and for which operating results are regularly reviewed by segment management. Our reporting units are the same as our operating segments. As of March 31, 2018 , goodwill and acquired intangible assets in the aggregate attributable to our Software Products segment was $1,391.0 million and our Professional Services segment was $30.6 million . As of September 30, 2017 , goodwill and acquired intangible assets in the aggregate attributable to our Software Products segment was $1,410.0 million and our Professional Services segment was $30.6 million . Acquired intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. We evaluate goodwill for impairment in the third quarter of our fiscal year, or on an interim basis if an event occurs or circumstances change that would, more likely than not, reduce the fair value of a reporting segment below its carrying value. Factors that could trigger an impairment review include significant under-performance relative to historical or projected future operating results, significant changes in our use of the acquired assets or the strategy for our overall business, significant negative industry or economic trends, a significant decline in our stock price for a sustained period and a reduction of our market capitalization relative to net book value. We completed our annual goodwill impairment review as of July 1, 2017 and we also completed a qualitative assessment of our goodwill by reporting unit prior to the change in our segments described above and concluded that no impairment charge was required as of those dates. Goodwill and acquired intangible assets consisted of the following: March 31, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value (in thousands) Goodwill (not amortized) $ 1,191,603 $ 1,182,772 Intangible assets with finite lives (amortized) (1): Purchased software $ 365,904 $ 243,809 $ 122,095 $ 362,955 $ 228,377 $ 134,578 Capitalized software 22,877 22,877 — 22,877 22,877 — Customer lists and relationships 362,895 259,569 103,326 359,932 241,554 118,378 Trademarks and trade names 19,270 14,661 4,609 19,138 14,186 4,952 Other 4,096 4,096 — 4,030 4,030 — $ 775,042 $ 545,012 $ 230,030 $ 768,932 $ 511,024 $ 257,908 Total goodwill and acquired intangible assets $ 1,421,633 $ 1,440,680 (1) The weighted-average useful lives of purchased software, customer lists and relationships, and trademarks and trade names with a remaining net book value are 9 years, 10 years, and 10 years, respectively. Goodwill Changes in goodwill presented by reportable segments were as follows: Software Products Professional Services Total (in thousands) Balance, October 1, 2017 $ 1,152,917 $ 29,855 $ 1,182,772 Acquisition 4,350 — 4,350 Foreign currency translation adjustment 4,368 113 4,481 Balance, March 31, 2018 $ 1,161,635 $ 29,968 $ 1,191,603 Amortization of Intangible Assets The aggregate amortization expense for intangible assets with finite lives was classified in our Consolidated Statements of Operations as follows: Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Amortization of acquired intangible assets $ 7,895 $ 7,946 $ 15,716 $ 16,013 Cost of license and subscription revenue 6,556 6,389 13,231 12,777 Total amortization expense $ 14,451 $ 14,335 $ 28,947 $ 28,790

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required to be recorded at fair value, we consider the principal or most advantageous market in which we would transact and consider assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions, and risk of nonperformance. Generally accepted accounting principles prescribe a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs that may be used to measure fair value: • Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2: inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; or • Level 3: unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Money market funds, time deposits and corporate notes/bonds are classified within Level 1 of the fair value hierarchy because they are valued based on quoted market prices in active markets. Certificates of deposit, commercial paper and certain U.S. government agency securities are classified within Level 2 of the fair value hierarchy. These instruments are valued based on quoted prices in markets that are not active or based on other observable inputs consisting of market yields, reported trades and broker/dealer quotes. The principal market in which we execute our foreign currency contracts is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large financial institutions. Our foreign currency contracts’ valuation inputs are based on quoted prices and quoted pricing intervals from public data sources and do not involve management judgment. These contracts are typically classified within Level 2 of the fair value hierarchy. The fair value of our contingent consideration arrangements is determined based on our evaluation of the probability and amount of any earn-out that will be achieved based on expected future performances by the acquired entities. These arrangements are classified within Level 3 of the fair value hierarchy. Our significant financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2018 and September 30, 2017 were as follows: March 31, 2018 Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Cash equivalents $ 82,291 $ — $ — $ 82,291 Marketable securities Certificates of deposit — 219 — 219 Corporate notes/bonds 52,650 — — 52,650 U.S. government agency securities — 2,395 — 2,395 Forward contracts — 827 — 827 $ 134,941 $ 3,441 $ — $ 138,382 Financial liabilities: Contingent consideration related to acquisitions $ — $ — $ 6,743 $ 6,743 Forward contracts — 4,837 — 4,837 $ — $ 4,837 $ 6,743 $ 11,580 September 30, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Cash equivalents $ 49,845 $ — $ — $ 49,845 Marketable securities Certificates of deposit — 240 — 240 Corporate notes/bonds 47,673 — — 47,673 U.S. government agency securities — 2,402 — 2,402 Forward contracts — 1,163 — 1,163 $ 97,518 $ 3,805 $ — $ 101,323 Financial liabilities: Contingent consideration related to acquisitions $ — $ — $ 8,400 $ 8,400 Forward contracts — 4,347 — 4,347 $ — $ 4,347 $ 8,400 $ 12,747 Changes in the fair value of Level 3 contingent consideration liability associated with our acquisitions were as follows: Contingent Consideration (in thousands) Kepware Other Total Balance, October 1, 2017 $ 8,400 $ — $ 8,400 Addition to contingent consideration — 2,100 2,100 Payment of contingent consideration (3,757 ) — (3,757 ) Balance, March 31, 2018 $ 4,643 $ 2,100 $ 6,743 Contingent Consideration (in thousands) ColdLight Kepware Total Balance, October 1, 2016 $ 2,500 $ 17,070 $ 19,570 Change in present value of contingent consideration — 148 148 Payment of contingent consideration (1,250 ) (1,800 ) (3,050 ) Balance, April 1, 2017 $ 1,250 $ 15,418 $ 16,668 In the Consolidated Balance Sheet as of March 31, 2018 , $5.7 million of the contingent consideration liability is included in accrued expenses and other current liabilities with the remaining $1.1 million in other liabilities. Of the $3.8 million payments in the first six months of 2018, $3.2 million represents the fair value of the liabilities recorded at the acquisition date and is included in financing activities in the Consolidated Statements of Cash Flows. Of the $3.1 million payments in the first six months of 2017, $2.7 million represents the fair value of the liabilities recorded at the acquisition date and is included in financing activities in the Consolidated Statements of Cash Flows. In connection with our acquisition of Kepware, the former shareholders were eligible to receive additional consideration of up to $18.0 million , which was contingent on the achievement of certain Financial Performance, Product Integration and Business Integration targets (as defined in the Stock Purchase Agreement) within 24 months from April 1, 2016. If such targets were achieved within the defined 12 month, 18 month and 24 month earn-out periods, the consideration corresponding to each target would be earned and payable in cash. The estimated undiscounted range of outcomes for the contingent consideration was $16.9 million to $18.0 million at the acquisition date. As of March 31, 2018, our estimate of the liability was $4.6 million , net of $13.4 million in payments made since the date of acquisition.

Marketable Securities

Marketable Securities	6 Months Ended
	Mar. 31, 2018
Marketable Securities [Abstract]
Marketable Securities	Marketable Securities The amortized cost and fair value of marketable securities as of March 31, 2018 and September 30, 2017 were as follows: March 31, 2018 Amortized cost Gross unrealized gains Gross unrealized losses Fair value (in thousands) Certificates of deposit $ 220 $ — $ (1 ) $ 219 Corporate notes/bonds 53,225 — (575 ) 52,650 U.S. government agency securities 2,408 — (13 ) 2,395 $ 55,853 $ — $ (589 ) $ 55,264 September 30, 2017 Amortized cost Gross unrealized gains Gross unrealized losses Fair value (in thousands) Certificates of deposit $ 240 $ — $ — $ 240 Corporate notes/bonds 47,811 2 (140 ) 47,673 U.S. government agency securities 2,407 — (5 ) 2,402 $ 50,458 $ 2 $ (145 ) $ 50,315 Our investment portfolio consists of certificates of deposit, commercial paper, corporate notes/bonds and government securities that have a maximum maturity of three years. The longer the duration of these securities, the more susceptible they are to changes in market interest rates and bond yields. All unrealized losses are due to changes in market interest rates, bond yields and/or credit ratings. We review our investments to identify and evaluate investments that have an indication of possible impairment. We concluded that, at March 31, 2018 , the unrealized losses were temporary. The following tables summarize the fair value and gross unrealized losses aggregated by category and the length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2018 and September 30, 2017 . March 31, 2018 Less than twelve months Greater than twelve months Total Fair Value Gross unrealized loss Fair Value Gross unrealized loss Fair Value Gross unrealized loss (in thousands) Certificates of deposit $ 219 $ (1 ) $ — $ — $ 219 $ (1 ) Corporate notes/bonds 30,712 (413 ) 21,938 (162 ) 52,650 (575 ) U.S. government agency securities — — 2,395 (13 ) 2,395 (13 ) $ 30,931 $ (414 ) $ 24,333 $ (175 ) $ 55,264 $ (589 ) September 30, 2017 Less than twelve months Greater than twelve months Total Fair Value Gross unrealized loss Fair Value Gross unrealized loss Fair Value Gross unrealized loss (in thousands) Certificates of deposit $ 240 $ — $ — $ — $ 240 $ — Corporate notes/bonds 15,254 (43 ) 28,885 (97 ) 44,139 (140 ) U.S. government agency securities — — 2,402 (5 ) 2,402 (5 ) $ 15,494 $ (43 ) $ 31,287 $ (102 ) $ 46,781 $ (145 ) The following table presents our available-for-sale marketable securities by contractual maturity date as of March 31, 2018 and September 30, 2017 . March 31, 2018 September 30, 2017 Amortized cost Fair value Amortized cost Fair value (in thousands) (in thousands) Due in one year or less $ 22,772 $ 22,636 $ 18,274 $ 18,244 Due after one year through three years 33,081 32,628 32,184 32,071 $ 55,853 $ 55,264 $ 50,458 $ 50,315

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments Our earnings and cash flows are subject to fluctuations due to changes in foreign currency exchange rates. Our most significant foreign currency exposures relate to Western European countries, Japan, China and Canada. Our foreign currency risk management strategy is principally designed to mitigate the future potential financial impact of changes in the U.S. Dollar value of anticipated transactions and balances denominated in foreign currency, resulting from changes in foreign currency exchange rates. We enter into derivative transactions, specifically foreign currency forward contracts, to manage the exposures to foreign currency exchange risk to reduce earnings volatility. We do not enter into derivatives transactions for trading or speculative purposes. Non-Designated Hedges We hedge our net foreign currency monetary assets and liabilities primarily resulting from foreign currency denominated receivables and payables with foreign exchange forward contracts to reduce the risk that our earnings and cash flows will be adversely affected by changes in foreign currency exchange rates. These contracts have maturities of up to approximately three months. Generally, we do not designate these foreign currency forward contracts as hedges for accounting purposes and changes in the fair value of these instruments are recognized immediately in earnings. Because we enter into forward contracts only as an economic hedge, any gain or loss on the underlying foreign-denominated balance would be offset by the loss or gain on the forward contract. Gains and losses on forward contracts and foreign denominated receivables and payables are included in interest income and other expense, net. As of March 31, 2018 and September 30, 2017 , we had outstanding forward contracts with notional amounts equivalent to the following: Currency Hedged March 31, September 30, (in thousands) Canadian / U.S. Dollar $ 7,500 $ 12,809 Swiss Franc / Euro — 7,157 Swiss Franc / U.S. Dollar 13,135 605 Chinese Yuan offshore / Euro — 10,423 Euro / U.S. Dollar 320,627 244,000 Japanese Yen / Euro 18,864 17,694 Israeli Shekel / U.S. Dollar 6,684 8,820 Japanese Yen / U.S. Dollar 5,611 3,198 Swedish Krona / U.S. Dollar 12,619 4,627 Danish Krona / U.S. Dollar 4,629 1,743 Brazilian Real / U.S. Dollar 3,117 — All other 8,725 7,443 Total $ 401,511 $ 318,519 The following table shows the effect of our non-designated hedges in the Consolidated Statements of Operations for the three and six months ended March 31, 2018 and April 1, 2017 : Derivatives Not Designated as Hedging Instruments Location of Gain or (Loss) Recognized in Income Net realized and unrealized gain or (loss) (excluding the underlying foreign currency exposure being hedged) Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Forward Contracts Interest income and other expense, net $ 2,435 $ 238 $ 3,022 $ (8,091 ) In the three and six months ended March 31, 2018 , foreign currency losses, net were $1.8 million and $3.2 million , respectively. In the three and six months ended April 1, 2017 , foreign currency losses, net were $1.0 million and $2.5 million , respectively. Cash Flow Hedges Our foreign exchange risk management program objective is to identify foreign exchange exposures and implement appropriate hedging strategies to minimize earnings fluctuations resulting from foreign exchange rate movements. We designate certain foreign exchange forward contracts as cash flow hedges of Euro, Yen and SEK denominated intercompany forecasted revenue transactions (supported by third party sales). All foreign exchange forward contracts are carried at fair value on the Consolidated Balance Sheets and the maximum duration of foreign exchange forward contracts is 15 months. Cash flow hedge relationships are designated at inception, and effectiveness is assessed prospectively and retrospectively using regression analysis on monthly. As the forward contracts are highly effective in offsetting changes to future cash flows on the hedged transactions, we record the effective portion of changes in these cash flow hedges in accumulated other comprehensive income and subsequently reclassify it into earnings in the period during which the hedged transactions are recognized in earnings. Changes in the fair value of foreign exchange forward contracts due to changes in time value are included in the assessment of effectiveness. Our derivatives are not subject to any credit contingent features. We manage credit risk with counterparties by trading among several counterparties and we review our counterparties’ credit at least quarterly. As of March 31, 2018 and September 30, 2017 , we had outstanding forward contracts designated as cash flow hedges with notional amounts equivalent to the following: Currency Hedged March 31, September 30, (in thousands) Euro / U.S. Dollar $ 55,744 $ 64,831 Japanese Yen / U.S. Dollar 20,077 22,675 SEK / U.S. Dollar 15,116 14,091 Total $ 90,937 $ 101,597 The following table shows the effect of our derivative instruments designated as cash flow hedges in the Consolidated Statements of Operations for the three and six months ended March 31, 2018 and April 1, 2017 (in thousands): Derivatives Designated as Hedging Instruments Gain or (Loss) Recognized in OCI-Effective Portion Location of Gain or (Loss) Reclassified from OCI into Income-Effective Portion Gain or (Loss) Reclassified from OCI into Income-Effective Portion Location of Gain or (Loss) Recognized-Ineffective Portion Gain or (Loss) Recognized-Ineffective Portion Three months ended Three months ended Three months ended March 31, April 1, March 31, April 1, March 31, April 1, Forward Contracts $ (2,339 ) $ (589 ) Subscription, support and license revenue $ (1,728 ) $ 567 Interest income and other expense, net $ (16 ) $ (4 ) Six months ended Six months ended Six months ended March 31, April 1, March 31, April 1, March 31, April 1, Forward Contracts $ (3,382 ) $ 2,882 Subscription, support and license revenue $ (2,382 ) $ 974 Interest income and other expense, net $ (35 ) $ 5 As of March 31, 2018 , we estimated that all amounts reported in accumulated other comprehensive income will be reclassified to income within the next twelve months. If an underlying forecast transaction does not occur, or it becomes probable that it will not occur, the related hedge gains and losses on the cash flow hedge would be immediately reclassified to interest income and other expense, net on the Consolidated Statements of Operations. For the three and six months ended March 31, 2018 and April 1, 2017 , there were no such gains or losses. The following table shows our derivative instruments measured at gross fair value as reflected in the Consolidated Balance Sheets: Fair Value of Derivatives Designated As Hedging Instruments Fair Value of Derivatives Not Designated As Hedging Instruments March 31, September 30, March 31, September 30, (in thousands) (in thousands) Derivative assets (1): Forward Contracts $ 296 $ 540 $ 531 $ 623 Derivative liabilities (2): Forward Contracts $ 3,119 $ 2,352 $ 1,718 $ 1,995 (1) As of March 31, 2018, $827 thousand current derivative assets are recorded in other current assets, in the Consolidated Balance Sheets. As of September 30, 2017, $1,128 thousand current derivative assets are recorded in other current assets, and $35 thousand long-term derivative assets are recorded in other assets in the Consolidated Balance Sheets. (2) As of March 31, 2018, $4,837 thousand current derivative liabilities are recorded in accrued expenses and other current liabilities in the Consolidated Balance Sheets. As of September 30, 2017, $4,329 thousand current derivative liabilities are recorded in accrued expenses and other current liabilities, and $18 thousand long term derivative liabilities are recorded in other liabilities in the Consolidated Balance Sheets. Offsetting Derivative Assets and Liabilities We have entered into master netting arrangements that allow net settlements under certain conditions. Although netting is permitted, it is currently our policy and practice to record all derivative assets and liabilities on a gross basis in the Consolidated Balance Sheets. The following table sets forth the offsetting of derivative assets as of March 31, 2018 : Gross Amounts Offset in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets As of March 31, 2018 Gross Amount of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount (in thousands) Forward Contracts $ 827 $ — $ 827 $ (827 ) $ — $ — The following table sets forth the offsetting of derivative liabilities as of March 31, 2018 : Gross Amounts Offset in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets As of March 31, 2018 Gross Amount of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets Financial Instruments Cash Collateral Pledged Net Amount (in thousands) Forward Contracts $ 4,837 $ — $ 4,837 $ (827 ) $ — $ 4,010

Segment Information

Segment Information	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information Effective with the beginning of fiscal 2018, we changed our segments, see Note 1. Basis of Presentation for additional information. We operate within a single industry segment -- computer software and related services. Operating segments as defined under GAAP are components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. Our chief operating decision maker is our President and Chief Executive Officer. We have two operating and reportable segments: (1) Software Products, which includes license, subscription and related support revenue (including updates and technical support) for all our products; and (2) Professional Services, which includes consulting, implementation and training services. We do not allocate sales & marketing or general and administrative expense to our operating segments as these activities are managed on a consolidated basis. Additionally, segment profit does not include stock-based compensation, amortization of intangible assets, restructuring charges and certain other identified costs that we do not allocate to the segments for purposes of evaluating their operational performance. The revenue and profit attributable to our operating segments are summarized below. We do not produce asset information by reportable segment; therefore, it is not reported. Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Software Products Revenue $ 262,453 $ 234,870 $ 527,643 $ 475,089 Operating Costs (1) 97,306 88,832 196,995 178,871 Profit 165,147 146,038 330,648 296,218 Professional Services Revenue 45,430 45,170 86,884 91,278 Operating Costs (2) 35,909 37,269 70,689 75,093 Profit 9,521 7,901 16,195 16,185 Total segment revenue 307,883 280,040 614,527 566,367 Total segment costs 133,215 126,101 267,684 253,964 Total segment profit 174,668 153,939 346,843 312,403 Unallocated operating expenses: Sales and marketing expenses 93,292 83,647 187,728 170,716 General and administrative expenses 27,382 25,957 54,814 54,007 Restructuring and headquarters relocation charges, net 114 464 219 6,749 Intangibles amortization 14,451 14,335 28,947 28,790 Stock-based compensation 17,026 21,577 35,357 39,565 Other unallocated operating expenses (3) 37 446 (60 ) 502 Total operating income 22,366 7,513 39,838 12,074 Interest expense (10,379 ) (11,725 ) (20,426 ) (22,040 ) Interest income and other expense, net (441 ) 3,156 (1,395 ) 2,407 Income (loss) before income taxes $ 11,546 $ (1,056 ) $ 18,017 $ (7,559 ) (1) Operating costs for the Software Products segment includes all cost of software revenue and research and development costs, excluding stock-based compensation and intangible amortization. (2) Operating costs for the Professional Services segment includes all cost of professional services revenue, excluding stock-based compensation, intangible amortization, and fair value adjustments for deferred services costs. (3) Other unallocated operating expenses include acquisition-related costs and fair value adjustments for deferred services costs.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes In the second quarter and first six months of 2018 , our effective tax rate was 31% on pre-tax income of $11.5 million , and (21)% on pre-tax income of $18.0 million , respectively, compared to (5)% on a pre-tax loss of $1.1 million , and (36)% on a pre-tax loss of $7.6 million in the second quarter and first six months of 2017 , respectively. In the first six months of 2018 and 2017 , our effective tax rate was lower than the statutory federal income tax rates ( 21% and 35% , respectively) due to U.S. tax reform, as described below, and our corporate structure in which our foreign taxes are at a net effective tax rate lower than the U.S. rate. A significant amount of our foreign earnings is generated by our subsidiaries organized in Ireland. In 2018 and 2017, the foreign rate differential predominantly relates to these Irish earnings. Our foreign rate differential in 2018 and 2017 includes the continuing rate benefit from a business realignment completed on September 30, 2014 in which intellectual property was transferred between two wholly-owned foreign subsidiaries. For the second quarter and first six months of 2018 and 2017 , this realignment resulted in tax benefits of approximately $7 million and $9 million , and $4 million and $12 million , respectively. On December 22, 2017, the United States enacted tax reform legislation through the Tax Cuts and Jobs Act, (the "Tax Act"), which significantly changed existing U.S. tax laws by a reduction of the corporate tax rate, the implementation of a new system of taxation for non-U.S. earnings, the imposition of a one-time tax on the deemed repatriation of undistributed earnings of non-U.S. subsidiaries, and by the expansion of the limitations on the deductibility of executive compensation and interest expense. As we have a September 30 fiscal year-end, there is a blended U.S. statutory federal rate of approximately 24.5% for our fiscal year ending September 30, 2018 and 21% for subsequent fiscal years. The Tax Act also provides that net operating losses generated in years ending after December 31, 2017 will be carried forward indefinitely and can no longer be carried back, and that net operating losses generated in years beginning after December 31, 2017 can only reduce taxable income by up to 80% when utilized in a future period. We estimate no federal income taxes payable as a result of the deemed repatriation of undistributed earnings as we estimate that the tax will be offset by a combination of current year losses and existing attributes which had a full valuation allowance recorded against the related deferred tax assets. In the first six months of 2018, we recorded a reasonable estimate of state income taxes payable on the deemed repatriation of $7.1 million . We also recorded a deferred tax benefit of $14.1 million as a reasonable estimate of the impact of the Tax Act on our net U.S. deferred income tax balances. This was primarily attributable to the reduction of the federal tax rate on the net deferred tax liability in the U.S., and the ability to realize net operating losses from the reversal of existing deferred tax assets which can now be carried forward indefinitely and can therefore be netted against deferred tax liabilities for indefinite lived intangible assets. We are continuing to assess the effects of the Tax Act on our indefinite reinvestment assertion and the realizability of our U.S. deferred tax assets. We are not able to make reasonable estimates at this time of the effects of certain provisions of the Tax Act that will apply to us beginning in our fiscal year ended September 30, 2019, including the Global Intangible Low Tax Income tax (the "GILTI" tax). The changes included in the Tax Act are broad and complex. The final transition impacts of the Tax Act may differ from the above estimates, possibly materially, due to, among other things, changes in interpretations of the Tax Act, any legislative action to address questions that arise because of the Tax Act, actions taken by U.S. state governments and taxing authorities in response to the Tax Act, any changes in accounting standards for income taxes or related interpretations in response to the Tax Act, or any updates or changes to estimates we have utilized to calculate the transition impacts, including impacts from changes to current year earnings estimates and foreign currency exchange rates of foreign subsidiaries. The Securities Exchange Commission has issued rules that allow for a measurement period of up to one year after the enactment date of the Tax Act to finalize the recording of the related tax impacts. We currently anticipate finalizing and recording any resulting adjustments by the end of our current fiscal year ending September 30, 2018. We have concluded, based on the weight of available evidence, that a full valuation allowance continues to be required against our U.S. net deferred tax assets as they are not more likely than not to be realized in the future. We will continue to reassess our valuation allowance requirements each financial reporting period. In the normal course of business, PTC and its subsidiaries are examined by various taxing authorities, including the Internal Revenue Service in the U.S. We regularly assess the likelihood of additional assessments by tax authorities and provide for these matters as appropriate. We are currently under audit by tax authorities in several jurisdictions. Audits by tax authorities typically involve examination of the deductibility of certain permanent items, limitations on net operating losses and tax credits. Although we believe our tax estimates are appropriate, the final determination of tax audits and any related litigation could result in material changes in our estimates. As of March 31, 2018 and September 30, 2017, we had unrecognized tax benefits of $14.3 million and $14.8 million , respectively. If all our unrecognized tax benefits as of March 31, 2018 were to become recognizable in the future, we would record a benefit to the income tax provision of $14.3 million , which would be partially offset by an increase in the U.S. valuation allowance of $3.9 million . Although we believe our tax estimates are appropriate, the final determination of tax audits and any related litigation could result in favorable or unfavorable changes in our estimates. We believe it is reasonably possible that within the next 12 months the amount of unrecognized tax benefits related to the resolution of multi-jurisdictional tax positions could be reduced by up to $7 million as audits close and statutes of limitations expire. In the fourth quarter of 2016, we received an assessment of approximately $12 million from the tax authorities in Korea. The assessment relates to various tax issues but primarily to foreign withholding taxes. We have appealed and intend to vigorously defend our positions. We believe that upon completion of a multi-level appeal process it is more likely than not that our positions will be sustained. Accordingly, we have not recorded a tax reserve for this matter. We paid this assessment in the first quarter of 2017 and have recorded the amount in other assets, pending resolution of the appeal process. In the first quarter of 2018, as a result of the adoption of ASU 2016-09, we recognized previously unrecognized tax benefits of $37.0 million as increases in deferred tax assets for tax loss carryovers and tax credits, primarily in the U.S. A corresponding increase to the valuation allowance was recorded for $36.9 million to the extent that it was not more likely than not that these benefits would be realized.

Debt

Debt	6 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt	Debt At March 31, 2018 and September 30, 2017 , we had the following long-term debt obligations: March 31, September 30, (in thousands) 6.000% Senior notes due 2024 $ 500,000 $ 500,000 Credit facility revolver 148,125 218,125 Total debt 648,125 718,125 Unamortized debt issuance costs for the Senior notes (1) (5,288 ) (5,719 ) Total debt, net of issuance costs (2) $ 642,837 $ 712,406 (1) Unamortized debt issuance costs related to the credit facility were $1.5 million and $2.0 million as of March 31, 2018 and September 30, 2017, respectively, and were included in other assets. (2) As of March 31, 2018 and September 30, 2017 all debt was included in long-term debt. Senior Notes In May 2016, we issued $500 million in aggregate principal amount of 6.0% senior, unsecured long-term debt at par value, due in 2024. We used the net proceeds from the sale of the notes to repay a portion of our outstanding revolving loan under our current credit facility. Interest is payable semi-annually on November 15 and May 15. The debt indenture includes covenants that limit our ability to, among other things, incur additional debt, grant liens on our properties or capital stock, enter into sale and leaseback transactions or asset sales, and make capital distributions. We were in compliance with all the covenants as of March 31, 2018 . On or after May 15, 2019, we may redeem the senior notes at any time in whole or from time to time in part at specified redemption prices. In certain circumstances constituting a change of control, we would be required to make an offer to repurchase the senior notes at a purchase price equal to 101% of the aggregate principal amount of the notes, plus accrued and unpaid interest. Our ability to repurchase the senior notes in such event may be limited by law, by the indenture associated with the senior notes, by our then-available financial resources or by the terms of other agreements to which we may be party at such time. If we fail to repurchase the senior notes as required by the indenture, it would constitute an event of default under the indenture governing the senior notes which, in turn, may also constitute an event of default under other obligations. As of March 31, 2018 , the total estimated fair value of the Notes was approximately $526.3 million , based on quoted prices for the notes on that date. Credit Agreement In November 2015, we entered into a multi-currency credit facility with a syndicate of sixteen banks for which JPMorgan Chase Bank, N.A. acts as Administrative Agent. We use the credit facility for general corporate purposes, including acquisitions of businesses, share repurchases and working capital requirements. As of March 31, 2018 , the fair value of our credit facility approximates its book value. The credit facility consists of a $600 million revolving loan commitment. The loan commitment may be increased by an additional $500 million (in the form of revolving loans or term loans, or a combination thereof) if the existing or additional lenders are willing to make such increased commitments. The revolving loan commitment does not require amortization of principal and may be repaid in whole or in part prior to the scheduled maturity date at our option without penalty or premium. The credit facility matures on September 15, 2019, when all remaining amounts outstanding will be due and payable in full. PTC and certain eligible foreign subsidiaries may borrow under the credit facility. Any borrowings by PTC Inc. under the credit facility would be guaranteed by PTC Inc.’s material domestic subsidiaries that become parties to the subsidiary guaranty, if any. As of the filing of this Form 10-Q, there are no subsidiary guarantors of the obligations under the credit facility. Any borrowings by eligible foreign subsidiary borrowers would be guaranteed by PTC Inc. and any subsidiary guarantors. In addition, PTC's and certain of its material domestic subsidiaries' owned property (including equity interests) is subject to first priority perfected liens in favor of the lenders of this credit facility. 100% of the voting equity interests of certain of PTC’s domestic subsidiaries and 65% of its material first-tier foreign subsidiaries are pledged as collateral for the obligations under the credit facility. As of March 31, 2018 , we had $148.1 million in loans outstanding under the credit facility. Loans under the credit facility bear interest at variable rates which reset every 30 to 180 days depending on the rate and period selected by PTC as described below. As of March 31, 2018 , the annual interest rate for borrowings outstanding was 3.25% . Interest rates on borrowings outstanding under the credit facility range from 1.25% to 1.75% above an adjusted LIBO rate for Euro currency borrowings or would range from 0.25% to 0.75% above the defined base rate (the greater of the Prime Rate, the FRBNY rate plus 0.5% , or an adjusted LIBO rate plus 1% ) for base rate borrowings, in each case based upon PTC’s total leverage ratio. Additionally, PTC may borrow certain foreign currencies at rates set in the same range above the respective London interbank offered interest rates for those currencies, based on PTC’s total leverage ratio. A quarterly commitment fee on the undrawn portion of the credit facility is required, ranging from 0.175% to 0.30% per annum based upon PTC’s total leverage ratio. The credit facility limits PTC’s and its subsidiaries’ ability to, among other things: incur liens or guarantee obligations; pay dividends (other than to PTC) and make other distributions; make investments and enter into joint ventures; dispose of assets; and engage in transactions with affiliates, except on an arms-length basis. Under the credit facility, PTC and its material domestic subsidiaries may not invest cash or property in, or loan to, PTC’s foreign subsidiaries in aggregate amounts exceeding $75.0 million for any purpose and an additional $200.0 million for acquisitions of businesses. In addition, under the credit facility, PTC and its subsidiaries must maintain the following financial ratios: • a total leverage ratio, defined as consolidated total indebtedness to the consolidated trailing four quarters EBITDA, not to exceed 4.50 to 1.00 as of the last day of any fiscal quarter; • a senior secured leverage ratio, defined as senior consolidated total indebtedness (which excludes unsecured indebtedness) to the consolidated trailing four quarters EBITDA, not to exceed 3.00 to 1.00 as of the last day of any fiscal quarter; and • a fixed charge coverage ratio, defined as the ratio of consolidated trailing four quarters EBITDA less consolidated capital expenditures to consolidated fixed charges, of not less than 3.50 to 1.00 as of the last day of any fiscal quarter. As of March 31, 2018 , our total leverage ratio was 2.14 to 1.00 , our senior secured leverage ratio was 0.52 to 1.00 and our fixed charge coverage ratio was 7.51 to 1.00 and we were in compliance with all financial and operating covenants of the credit facility. Any failure to comply with the financial or operating covenants of the credit facility would prevent PTC from being able to borrow additional funds, and would constitute a default, permitting the lenders to, among other things, accelerate the amounts outstanding, including all accrued interest and unpaid fees, under the credit facility and to terminate the credit facility. A change in control of PTC, as defined in the agreement, also constitutes an event of default, permitting the lenders to accelerate the indebtedness and terminate the credit facility.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal and Regulatory Matters Korean Tax Audit In July 2016, we received an assessment of approximately $12 million from the tax authorities in Korea related to an ongoing tax audit. See Note 11. Income Taxes for additional information. Legal Proceedings We are subject to various other legal proceedings and claims that arise in the ordinary course of business. We do not believe that resolving the legal proceedings and claims that we are currently subject to will have a material adverse impact on our financial condition, results of operations or cash flows. However, the results of legal proceedings cannot be predicted with certainty. Should any of these legal proceedings and claims be resolved against us, the operating results for a reporting period could be adversely affected. Accruals With respect to legal proceedings and claims, we record an accrual for a contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. For legal proceedings and claims for which the likelihood that a liability has been incurred is more than remote but less than probable, we estimate the range of possible outcomes. As of March 31, 2018 , we estimate approximately $1.2 million to $3.4 million in legal proceedings and claims, of which we had accrued $1.2 million . Accounts Receivable Accounts receivable as of March 31, 2018 includes an amount invoiced under a multi-year contract for which the period of performance, and related revenue recognized, has spanned a number of years (with no revenue recognized since the first quarter of 2017). The invoiced amount is being disputed by the customer. If we are unable to recover amounts owed through a mutual business resolution, we intend to vigorously pursue collection of the full invoiced amount. If we are unsuccessful in collecting the full invoiced amount, there could be a write-down of accounts receivable and professional services revenue, which could range from $0 to $17.3 million . Guarantees and Indemnification Obligations We enter into standard indemnification agreements in the ordinary course of our business. Under such agreements with our business partners or customers, we indemnify, hold harmless, and agree to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally in connection with patent, copyright or other intellectual property infringement claims by any third party with respect to our products, as well as claims relating to property damage or personal injury resulting from the performance of services by us or our subcontractors. The maximum potential amount of future payments we could be required to make under these indemnification agreements is unlimited. Historically, our costs to defend lawsuits or settle claims relating to such indemnity agreements have been minimal and, accordingly, we believe the estimated fair value of liabilities under these agreements is immaterial. We warrant that our software products will perform in all material respects in accordance with our standard published specifications in effect at the time of delivery of the licensed products for a specified period of time. Additionally, we generally warrant that our consulting services will be performed consistent with generally accepted industry standards. In most cases, liability for these warranties is capped. If necessary, we would provide for the estimated cost of product and service warranties based on specific warranty claims and claim history; however, we have not incurred significant cost under our product or services warranties. As a result, we believe the estimated fair value of these liabilities is immaterial.

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events	6 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Borrowings In April 2018, we borrowed $150 million and subsequently repaid $50 million under our credit facility. The borrowings were made for the repurchase of shares of our common stock and to fund working capital requirements. Share Repurchases We resumed our share repurchase program and entered into a $100 million accelerated share repurchase ("ASR") agreement with a major financial institution ("Bank") on April 20, 2018. We used cash from borrowings under our credit facility to make the repurchase. On April 20, 2018, 951,814 shares were repurchased at the market price of $84.05 per share, totaling $80 million . The remaining $20 million represents the amount held back by the Bank pending final settlement of the ASR. Upon settlement of the ASR, the total shares repurchased by us will equal up to $100 million divided by a share price equal to the average daily volume weighted-average price of our common stock during the term of the ASR program less a fixed per share discount. Final settlement of the ASR will occur no later than June 26, 2018 at the Bank's discretion. All shares repurchased are automatically restored to the status of authorized and unissued.

Restructuring and Headquarter22

Restructuring and Headquarters Relocation Charges (Tables)	6 Months Ended
	Mar. 31, 2018
Restructuring [Abstract]
Restructuring Accrual Activity	The following table summarizes restructuring accrual activity for the six months ended March 31, 2018 : Employee severance and related benefits Facility closures and related costs Total (in thousands) October 1, 2017 $ 1,736 $ 4,508 $ 6,244 Credit to operations, net (395 ) (339 ) (734 ) Cash disbursements (1,120 ) (806 ) (1,926 ) Foreign exchange impact 22 (47 ) (25 ) Accrual, March 31, 2018 $ 243 $ 3,316 $ 3,559 The following table summarizes restructuring accrual activity for the six months ended April 1, 2017 : Employee severance and related benefits Facility closures and related costs Total (in thousands) October 1, 2016 $ 35,177 $ 1,431 $ 36,608 Charges to operations, net 2,861 3,888 6,749 Cash disbursements (28,060 ) (880 ) (28,940 ) Other non-cash charges — (260 ) (260 ) Foreign exchange impact (1,002 ) (6 ) (1,008 ) Accrual, April 1, 2017 $ 8,976 $ 4,173 $ 13,149

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Mar. 31, 2018
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Schedule of Restricted Stock and Restricted Stock Unit Activity	Restricted stock unit activity for the six months ended March 31, 2018 Shares Weighted Average Grant Date Fair Value (Per Share) (in thousands) Balance of outstanding restricted stock units October 1, 2017 3,487 $ 45.57 Granted (1) 1,355 $ 62.86 Vested (1,376 ) $ 44.42 Forfeited or not earned (471 ) $ 51.37 Balance of outstanding restricted stock units March 31, 2018 2,995 $ 53.03 _________________ (1) Restricted stock granted includes 184,000 shares from prior period TSR awards that were earned upon achievement of the performance criteria and vested in November 2018.
Schedule of Restricted Stock Unit Grants for the Period	Restricted Stock Units Grant Period Performance-based RSUs (1) Service-based RSUs (2) (Number of Units in thousands) First six months of 2018 461 710 _________________ (1) Substantially all the performance-based RSUs were granted to our executive officers. Approximately 189,000 shares are eligible to vest based upon annual performance measures, measured over a three -year period. RSUs not earned for a period may be earned in the third period. An additional 250,000 shares are eligible to vest based upon a 2018 performance measure. To the extent earned, those performance-based RSUs will vest in three substantially equal installments on November 15, 2018, November 15, 2019 and November 15, 2020, or the date the Compensation Committee determines the extent to which the applicable performance criteria have been achieved for each performance period. (2) The service-based RSUs were granted to employees, our executive officers and our directors. Substantially all service-based RSUs will vest in three substantially equal annual installments on or about the anniversary of the date of grant.
Schedule of Classification of Compensation Expense	Compensation expense recorded for our stock-based awards was classified in our Consolidated Statements of Operations as follows: Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Cost of license and subscription revenue $ 408 $ 314 $ 821 $ 607 Cost of support revenue 690 1,355 1,498 2,499 Cost of professional services revenue 1,669 1,539 3,375 2,995 Sales and marketing 5,038 4,130 9,917 7,751 Research and development 3,383 3,951 6,343 6,948 General and administrative 5,838 10,288 13,403 18,765 Total stock-based compensation expense $ 17,026 $ 21,577 $ 35,357 $ 39,565

Earnings per Share (EPS) and 24

Earnings per Share (EPS) and Common Stock (Tables)	6 Months Ended
	Mar. 31, 2018
Earnings Per Share and Common Stock
Earnings(loss) per Share Basic and Diluted	Three months ended Six months ended Calculation of Basic and Diluted EPS March 31, April 1, March 31, April 1, (in thousands, except per share data) Net income (loss) $ 7,922 $ (1,104 ) $ 21,799 $ (10,245 ) Weighted average shares outstanding—Basic 116,241 115,709 115,986 115,498 Dilutive effect of restricted stock units 1,664 — 1,794 — Weighted average shares outstanding—Diluted 117,905 115,709 117,780 115,498 Earnings (loss) per share—Basic $ 0.07 $ (0.01 ) $ 0.19 $ (0.09 ) Earnings (loss) per share—Diluted $ 0.07 $ (0.01 ) $ 0.19 $ (0.09 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Acquired Intangible Assets	Goodwill and acquired intangible assets consisted of the following: March 31, 2018 September 30, 2017 Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value (in thousands) Goodwill (not amortized) $ 1,191,603 $ 1,182,772 Intangible assets with finite lives (amortized) (1): Purchased software $ 365,904 $ 243,809 $ 122,095 $ 362,955 $ 228,377 $ 134,578 Capitalized software 22,877 22,877 — 22,877 22,877 — Customer lists and relationships 362,895 259,569 103,326 359,932 241,554 118,378 Trademarks and trade names 19,270 14,661 4,609 19,138 14,186 4,952 Other 4,096 4,096 — 4,030 4,030 — $ 775,042 $ 545,012 $ 230,030 $ 768,932 $ 511,024 $ 257,908 Total goodwill and acquired intangible assets $ 1,421,633 $ 1,440,680 (1) The weighted-average useful lives of purchased software, customer lists and relationships, and trademarks and trade names with a remaining net book value are 9 years, 10 years, and 10 years, respectively.
Schedule of Goodwill	Changes in goodwill presented by reportable segments were as follows: Software Products Professional Services Total (in thousands) Balance, October 1, 2017 $ 1,152,917 $ 29,855 $ 1,182,772 Acquisition 4,350 — 4,350 Foreign currency translation adjustment 4,368 113 4,481 Balance, March 31, 2018 $ 1,161,635 $ 29,968 $ 1,191,603
Amortization of Intangible Assets	The aggregate amortization expense for intangible assets with finite lives was classified in our Consolidated Statements of Operations as follows: Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Amortization of acquired intangible assets $ 7,895 $ 7,946 $ 15,716 $ 16,013 Cost of license and subscription revenue 6,556 6,389 13,231 12,777 Total amortization expense $ 14,451 $ 14,335 $ 28,947 $ 28,790

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	Our significant financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2018 and September 30, 2017 were as follows: March 31, 2018 Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Cash equivalents $ 82,291 $ — $ — $ 82,291 Marketable securities Certificates of deposit — 219 — 219 Corporate notes/bonds 52,650 — — 52,650 U.S. government agency securities — 2,395 — 2,395 Forward contracts — 827 — 827 $ 134,941 $ 3,441 $ — $ 138,382 Financial liabilities: Contingent consideration related to acquisitions $ — $ — $ 6,743 $ 6,743 Forward contracts — 4,837 — 4,837 $ — $ 4,837 $ 6,743 $ 11,580 September 30, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Cash equivalents $ 49,845 $ — $ — $ 49,845 Marketable securities Certificates of deposit — 240 — 240 Corporate notes/bonds 47,673 — — 47,673 U.S. government agency securities — 2,402 — 2,402 Forward contracts — 1,163 — 1,163 $ 97,518 $ 3,805 $ — $ 101,323 Financial liabilities: Contingent consideration related to acquisitions $ — $ — $ 8,400 $ 8,400 Forward contracts — 4,347 — 4,347 $ — $ 4,347 $ 8,400 $ 12,747
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Changes in the fair value of Level 3 contingent consideration liability associated with our acquisitions were as follows: Contingent Consideration (in thousands) Kepware Other Total Balance, October 1, 2017 $ 8,400 $ — $ 8,400 Addition to contingent consideration — 2,100 2,100 Payment of contingent consideration (3,757 ) — (3,757 ) Balance, March 31, 2018 $ 4,643 $ 2,100 $ 6,743 Contingent Consideration (in thousands) ColdLight Kepware Total Balance, October 1, 2016 $ 2,500 $ 17,070 $ 19,570 Change in present value of contingent consideration — 148 148 Payment of contingent consideration (1,250 ) (1,800 ) (3,050 ) Balance, April 1, 2017 $ 1,250 $ 15,418 $ 16,668

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Mar. 31, 2018
Marketable Securities [Abstract]
Marketable Securities	The amortized cost and fair value of marketable securities as of March 31, 2018 and September 30, 2017 were as follows: March 31, 2018 Amortized cost Gross unrealized gains Gross unrealized losses Fair value (in thousands) Certificates of deposit $ 220 $ — $ (1 ) $ 219 Corporate notes/bonds 53,225 — (575 ) 52,650 U.S. government agency securities 2,408 — (13 ) 2,395 $ 55,853 $ — $ (589 ) $ 55,264 September 30, 2017 Amortized cost Gross unrealized gains Gross unrealized losses Fair value (in thousands) Certificates of deposit $ 240 $ — $ — $ 240 Corporate notes/bonds 47,811 2 (140 ) 47,673 U.S. government agency securities 2,407 — (5 ) 2,402 $ 50,458 $ 2 $ (145 ) $ 50,315
Unrealized Gain (Loss) on Investments	The following tables summarize the fair value and gross unrealized losses aggregated by category and the length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2018 and September 30, 2017 . March 31, 2018 Less than twelve months Greater than twelve months Total Fair Value Gross unrealized loss Fair Value Gross unrealized loss Fair Value Gross unrealized loss (in thousands) Certificates of deposit $ 219 $ (1 ) $ — $ — $ 219 $ (1 ) Corporate notes/bonds 30,712 (413 ) 21,938 (162 ) 52,650 (575 ) U.S. government agency securities — — 2,395 (13 ) 2,395 (13 ) $ 30,931 $ (414 ) $ 24,333 $ (175 ) $ 55,264 $ (589 ) September 30, 2017 Less than twelve months Greater than twelve months Total Fair Value Gross unrealized loss Fair Value Gross unrealized loss Fair Value Gross unrealized loss (in thousands) Certificates of deposit $ 240 $ — $ — $ — $ 240 $ — Corporate notes/bonds 15,254 (43 ) 28,885 (97 ) 44,139 (140 ) U.S. government agency securities — — 2,402 (5 ) 2,402 (5 ) $ 15,494 $ (43 ) $ 31,287 $ (102 ) $ 46,781 $ (145 )
Investments Classified by Contractual Maturity Date	The following table presents our available-for-sale marketable securities by contractual maturity date as of March 31, 2018 and September 30, 2017 . March 31, 2018 September 30, 2017 Amortized cost Fair value Amortized cost Fair value (in thousands) (in thousands) Due in one year or less $ 22,772 $ 22,636 $ 18,274 $ 18,244 Due after one year through three years 33,081 32,628 32,184 32,071 $ 55,853 $ 55,264 $ 50,458 $ 50,315

Derivative Financial Instrume28

Derivative Financial Instruments (Tables)	6 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Forward Contracts	As of March 31, 2018 and September 30, 2017 , we had outstanding forward contracts with notional amounts equivalent to the following: Currency Hedged March 31, September 30, (in thousands) Canadian / U.S. Dollar $ 7,500 $ 12,809 Swiss Franc / Euro — 7,157 Swiss Franc / U.S. Dollar 13,135 605 Chinese Yuan offshore / Euro — 10,423 Euro / U.S. Dollar 320,627 244,000 Japanese Yen / Euro 18,864 17,694 Israeli Shekel / U.S. Dollar 6,684 8,820 Japanese Yen / U.S. Dollar 5,611 3,198 Swedish Krona / U.S. Dollar 12,619 4,627 Danish Krona / U.S. Dollar 4,629 1,743 Brazilian Real / U.S. Dollar 3,117 — All other 8,725 7,443 Total $ 401,511 $ 318,519 As of March 31, 2018 and September 30, 2017 , we had outstanding forward contracts designated as cash flow hedges with notional amounts equivalent to the following: Currency Hedged March 31, September 30, (in thousands) Euro / U.S. Dollar $ 55,744 $ 64,831 Japanese Yen / U.S. Dollar 20,077 22,675 SEK / U.S. Dollar 15,116 14,091 Total $ 90,937 $ 101,597
Net Gains and Losses on Foreign Currency Exposures	The following table shows the effect of our non-designated hedges in the Consolidated Statements of Operations for the three and six months ended March 31, 2018 and April 1, 2017 : Derivatives Not Designated as Hedging Instruments Location of Gain or (Loss) Recognized in Income Net realized and unrealized gain or (loss) (excluding the underlying foreign currency exposure being hedged) Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Forward Contracts Interest income and other expense, net $ 2,435 $ 238 $ 3,022 $ (8,091 ) The following table shows the effect of our derivative instruments designated as cash flow hedges in the Consolidated Statements of Operations for the three and six months ended March 31, 2018 and April 1, 2017 (in thousands): Derivatives Designated as Hedging Instruments Gain or (Loss) Recognized in OCI-Effective Portion Location of Gain or (Loss) Reclassified from OCI into Income-Effective Portion Gain or (Loss) Reclassified from OCI into Income-Effective Portion Location of Gain or (Loss) Recognized-Ineffective Portion Gain or (Loss) Recognized-Ineffective Portion Three months ended Three months ended Three months ended March 31, April 1, March 31, April 1, March 31, April 1, Forward Contracts $ (2,339 ) $ (589 ) Subscription, support and license revenue $ (1,728 ) $ 567 Interest income and other expense, net $ (16 ) $ (4 ) Six months ended Six months ended Six months ended March 31, April 1, March 31, April 1, March 31, April 1, Forward Contracts $ (3,382 ) $ 2,882 Subscription, support and license revenue $ (2,382 ) $ 974 Interest income and other expense, net $ (35 ) $ 5
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table shows our derivative instruments measured at gross fair value as reflected in the Consolidated Balance Sheets: Fair Value of Derivatives Designated As Hedging Instruments Fair Value of Derivatives Not Designated As Hedging Instruments March 31, September 30, March 31, September 30, (in thousands) (in thousands) Derivative assets (1): Forward Contracts $ 296 $ 540 $ 531 $ 623 Derivative liabilities (2): Forward Contracts $ 3,119 $ 2,352 $ 1,718 $ 1,995 (1) As of March 31, 2018, $827 thousand current derivative assets are recorded in other current assets, in the Consolidated Balance Sheets. As of September 30, 2017, $1,128 thousand current derivative assets are recorded in other current assets, and $35 thousand long-term derivative assets are recorded in other assets in the Consolidated Balance Sheets. (2) As of March 31, 2018, $4,837 thousand current derivative liabilities are recorded in accrued expenses and other current liabilities in the Consolidated Balance Sheets. As of September 30, 2017, $4,329 thousand current derivative liabilities are recorded in accrued expenses and other current liabilities, and $18 thousand long term derivative liabilities are recorded in other liabilities in the Consolidated Balance Sheets.
Offsetting Assets	The following table sets forth the offsetting of derivative assets as of March 31, 2018 : Gross Amounts Offset in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets As of March 31, 2018 Gross Amount of Recognized Assets Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets Presented in the Consolidated Balance Sheets Financial Instruments Cash Collateral Received Net Amount (in thousands) Forward Contracts $ 827 $ — $ 827 $ (827 ) $ — $ —
Offsetting Liabilities	The following table sets forth the offsetting of derivative liabilities as of March 31, 2018 : Gross Amounts Offset in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets As of March 31, 2018 Gross Amount of Recognized Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Liabilities Presented in the Consolidated Balance Sheets Financial Instruments Cash Collateral Pledged Net Amount (in thousands) Forward Contracts $ 4,837 $ — $ 4,837 $ (827 ) $ — $ 4,010

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Revenue and Operating Income	The revenue and profit attributable to our operating segments are summarized below. We do not produce asset information by reportable segment; therefore, it is not reported. Three months ended Six months ended March 31, April 1, March 31, April 1, (in thousands) Software Products Revenue $ 262,453 $ 234,870 $ 527,643 $ 475,089 Operating Costs (1) 97,306 88,832 196,995 178,871 Profit 165,147 146,038 330,648 296,218 Professional Services Revenue 45,430 45,170 86,884 91,278 Operating Costs (2) 35,909 37,269 70,689 75,093 Profit 9,521 7,901 16,195 16,185 Total segment revenue 307,883 280,040 614,527 566,367 Total segment costs 133,215 126,101 267,684 253,964 Total segment profit 174,668 153,939 346,843 312,403 Unallocated operating expenses: Sales and marketing expenses 93,292 83,647 187,728 170,716 General and administrative expenses 27,382 25,957 54,814 54,007 Restructuring and headquarters relocation charges, net 114 464 219 6,749 Intangibles amortization 14,451 14,335 28,947 28,790 Stock-based compensation 17,026 21,577 35,357 39,565 Other unallocated operating expenses (3) 37 446 (60 ) 502 Total operating income 22,366 7,513 39,838 12,074 Interest expense (10,379 ) (11,725 ) (20,426 ) (22,040 ) Interest income and other expense, net (441 ) 3,156 (1,395 ) 2,407 Income (loss) before income taxes $ 11,546 $ (1,056 ) $ 18,017 $ (7,559 ) (1) Operating costs for the Software Products segment includes all cost of software revenue and research and development costs, excluding stock-based compensation and intangible amortization. (2) Operating costs for the Professional Services segment includes all cost of professional services revenue, excluding stock-based compensation, intangible amortization, and fair value adjustments for deferred services costs. (3) Other unallocated operating expenses include acquisition-related costs and fair value adjustments for deferred services costs.

Debt Debt (Tables)

Debt Debt (Tables)	6 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Debt	At March 31, 2018 and September 30, 2017 , we had the following long-term debt obligations: March 31, September 30, (in thousands) 6.000% Senior notes due 2024 $ 500,000 $ 500,000 Credit facility revolver 148,125 218,125 Total debt 648,125 718,125 Unamortized debt issuance costs for the Senior notes (1) (5,288 ) (5,719 ) Total debt, net of issuance costs (2) $ 642,837 $ 712,406 (1) Unamortized debt issuance costs related to the credit facility were $1.5 million and $2.0 million as of March 31, 2018 and September 30, 2017, respectively, and were included in other assets. (2) As of March 31, 2018 and September 30, 2017 all debt was included in long-term debt.

Basis of Presentation (Details)

Basis of Presentation (Details) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)Segment	Dec. 30, 2017Segment	Apr. 01, 2017USD ($)	Sep. 30, 2017Segment	Oct. 01, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | Segment	2	2		3
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Windfall Tax Deductions Not Yet Recognized					$ 37
Windfall Tax Deductions Not Yet Recognized Offset Valuation Allowance					36.9
Excess Tax Benefit from Share-based Compensation, Operating Activities			$ 0.1
Excess tax benefits realized from stock-based awards			$ 0.1
forfeiture adjustment					$ 0.7
Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Tax Assets, Other	$ 77

Deferred Revenue and Related 32

Deferred Revenue and Related Customer Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017
Other Assets
Deferred Revenue and Financing Receivables [Line Items]
Billed but uncollected support and subscription related receivable	$ 132.1	$ 160.9

Restructuring and Headquarter33

Restructuring and Headquarters Relocation Charges - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended		29 Months Ended
	Mar. 31, 2018USD ($)	Apr. 01, 2017USD ($)	Mar. 31, 2018USD ($)	Apr. 01, 2017USD ($)	Mar. 31, 2018USD ($)employee	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	$ 114	$ 464	$ 219	$ 6,749	$ 84,700
Restructuring and Related Cost, Number of Positions Eliminated | employee					800
Headquarters relocation charges	1,000
Employee severance and related benefits
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net			(395)	2,861
Restructuring Reserve	243	8,976	243	8,976	$ 243	$ 1,736	$ 35,177
Facility closures and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net			(339)	3,888
Restructuring Reserve	3,316	4,173	3,316	4,173	3,316	4,508	1,431
Assumed Sublease Income	3,400		3,400		3,400
Total 2016 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net			(734)	6,749
Restructuring Reserve	3,559	$ 13,149	3,559	$ 13,149	3,559	$ 6,244	$ 36,608
Accrued Expenses and Other Current Liabilities [Member] | Facility closures and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	1,900		1,900		1,900
Other Noncurrent Liabilities [Member] | Facility closures and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 1,400		$ 1,400		$ 1,400

Restructuring and Headquarter34

Restructuring and Headquarters Relocation Charges - Schedule of Restructuring Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		29 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Credit to operations, net	$ 114	$ 464	$ 219	$ 6,749	$ 84,700
Employee severance and related benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			1,736	35,177
Credit to operations, net			(395)	2,861
Cash disbursements			(1,120)	(28,060)
Other non-cash charges				0
Foreign exchange impact			22	(1,002)
Restructuring reserve, ending balance	243	8,976	243	8,976	243
Facility closures and related costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			4,508	1,431
Credit to operations, net			(339)	3,888
Cash disbursements			(806)	(880)
Other non-cash charges				(260)
Foreign exchange impact			(47)	(6)
Restructuring reserve, ending balance	3,316	4,173	3,316	4,173	3,316
Total 2016 Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			6,244	36,608
Credit to operations, net			(734)	6,749
Cash disbursements			(1,926)	(28,940)
Other non-cash charges				(260)
Foreign exchange impact			(25)	(1,008)
Restructuring reserve, ending balance	$ 3,559	$ 13,149	$ 3,559	$ 13,149	$ 3,559

Stock-based Compensation (Narra

Stock-based Compensation (Narrative) (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2018USD ($)shares / unit	Apr. 01, 2017USD ($)	Mar. 31, 2018USD ($)shares / unit	Apr. 01, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Common Stock Issuable per Restricted Stock Unit | shares / unit	1		1
ESPP maximum contribution percentage	10.00%		10.00%
ESPP maximum contribution amount by employee			$ 25,000
ESPP purchase price as a % of stock price	85.00%		85.00%
Stock-based compensation	$ 17,026,000	$ 21,577,000	$ 35,357,000	$ 39,565,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1,000,000	$ 700,000	$ 2,100,000	$ 1,300,000

Stock-based Compensation (Sched

Stock-based Compensation (Schedule of Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs) shares in Thousands	6 Months Ended
	Mar. 31, 2018$ / sharesshares
Shares
Balance of outstanding restricted stock units, beginning, Shares | shares	3,487
Granted, shares | shares	1,355
Vested, Shares | shares	(1,376)
Forfeited or not earned, Shares | shares	(471)
Balance of outstanding restricted stock units, ending, Shares | shares	2,995
Weighted Average Grant Date Fair Value (Per Share)
Balance of outstanding restricted stock units, beginning (in USD per share) | $ / shares	$ 45.57
Granted (in USD per share) | $ / shares	62.86
Vested (in USD per share) | $ / shares	44.42
Forfeited or not earned (in USD per share) | $ / shares	51.37
Balance of outstanding restricted stock units, ending (in USD per share) | $ / shares	$ 53.03

Stock-based Compensation (Sch37

Stock-based Compensation (Schedule of Restricted Stock Unit Grants For The Period) (Details) shares in Thousands	6 Months Ended
	Mar. 31, 2018installmentshares
TSR Units [Member]
Granted, shares	184
Performance-Based Restricted Stock Units [Member]
Granted, shares	461
Award vesting period	3 years
Number of equal annual installments | installment	3
Service-Based Restricted Stock Units [Member]
Granted, shares	710
Number of equal annual installments | installment	3
Catch-Up Provision [Member] | Maximum | Performance-Based Restricted Stock Units [Member]
Granted, shares	189
No Catch-Up Provision [Member] | Maximum | Performance-Based Restricted Stock Units [Member]
Granted, shares	250

Stock-based Compensation (Sch38

Stock-based Compensation (Schedule of Classification of Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Total stock-based compensation expense	$ 17,026	$ 21,577	$ 35,357	$ 39,565
Cost of license and subscription revenue
Total stock-based compensation expense	408	314	821	607
Cost of support revenue
Total stock-based compensation expense	690	1,355	1,498	2,499
Cost of professional services revenue
Total stock-based compensation expense	1,669	1,539	3,375	2,995
Sales and marketing
Total stock-based compensation expense	5,038	4,130	9,917	7,751
Research and development
Total stock-based compensation expense	3,383	3,951	6,343	6,948
General and administrative
Total stock-based compensation expense	$ 5,838	$ 10,288	$ 13,403	$ 18,765

Earnings per Share (EPS) and 39

Earnings per Share (EPS) and Common Stock (Earnings per Share Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Earnings Per Share and Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			0	1,800
Net income (loss)	$ 7,922	$ (1,104)	$ 21,799	$ (10,245)
Weighted average shares outstanding—Basic (in shares)	116,241	115,709	115,986	115,498
Dilutive effect of employee stock options, restricted shares and restricted stock units (in shares)	1,664	0	1,794	0
Weighted average shares outstanding—Diluted (in shares)	117,905	115,709	117,780	115,498
Earnings(loss) per share—Basic (in USD per share)	$ 0.07	$ (0.01)	$ 0.19	$ (0.09)
Earnings(loss) per share—Diluted (in USD per share)	$ 0.07	$ (0.01)	$ 0.19	$ (0.09)

Earnings per Share (EPS) and 40

Earnings per Share (EPS) and Common Stock (Narrative) (Details) - USD ($)	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Apr. 20, 2018	Sep. 30, 2017
Earnings Per Share and Common Stock
Stock option restricted shares and restricted stock units excluded from computation of EPS, shares	0	1,800,000
Common stock, shares authorized	500,000,000			500,000,000
Stock Repurchase Program, Authorized Amount	$ 500,000,000
Subsequent Event [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Accelerated Share Repurchases, Settlement (Payment) or Receipt			$ 100,000,000

Goodwill and Intangible Asset41

Goodwill and Intangible Assets (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)Segment	Dec. 30, 2017Segment	Mar. 31, 2018USD ($)	Sep. 30, 2017USD ($)Segment
Number of operating segments | Segment	2	2		3
Number of reportable segments | Segment	2			3
Intangible Assets, Net (Including Goodwill)	$ 1,421,633		$ 1,421,633	$ 1,440,680
Foreign currency translation adjustment			4,481
Goodwill	1,191,603		1,191,603	1,182,772
Professional Services
Intangible Assets, Net (Including Goodwill)	30,600		30,600	30,600
Foreign currency translation adjustment			113
Goodwill	29,968		29,968	29,855
Software Products
Intangible Assets, Net (Including Goodwill)	1,391,000		1,391,000	1,410,000
Foreign currency translation adjustment			4,368
Goodwill	$ 1,161,635		$ 1,161,635	$ 1,152,917

Goodwill and Intangible Asset42

Goodwill and Intangible Assets (Goodwill and Acquired Intangible Assets) (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Sep. 30, 2017
Goodwill (not amortized), Net Book Value	$ 1,191,603	$ 1,182,772
Intangible assets with finite lives (amortized), Gross Carrying Amount	775,042	768,932
Intangible assets with finite lives (amortized), Accumulated Amortization	545,012	511,024
Intangible assets with finite lives (amortized), Net Book Value	230,030	257,908
Intangible Assets, Net (Including Goodwill)	1,421,633	1,440,680
Purchased software
Intangible assets with finite lives (amortized), Gross Carrying Amount	365,904	362,955
Intangible assets with finite lives (amortized), Accumulated Amortization	243,809	228,377
Intangible assets with finite lives (amortized), Net Book Value	$ 122,095	134,578
Acquired finite-lived intangible asset, weighted average useful life	9 years
Capitalized software
Intangible assets with finite lives (amortized), Gross Carrying Amount	$ 22,877	22,877
Intangible assets with finite lives (amortized), Accumulated Amortization	22,877	22,877
Intangible assets with finite lives (amortized), Net Book Value	0	0
Customer lists and relationships
Intangible assets with finite lives (amortized), Gross Carrying Amount	362,895	359,932
Intangible assets with finite lives (amortized), Accumulated Amortization	259,569	241,554
Intangible assets with finite lives (amortized), Net Book Value	$ 103,326	118,378
Acquired finite-lived intangible asset, weighted average useful life	10 years
Trademarks and trade names
Intangible assets with finite lives (amortized), Gross Carrying Amount	$ 19,270	19,138
Intangible assets with finite lives (amortized), Accumulated Amortization	14,661	14,186
Intangible assets with finite lives (amortized), Net Book Value	$ 4,609	4,952
Acquired finite-lived intangible asset, weighted average useful life	10 years
Other
Intangible assets with finite lives (amortized), Gross Carrying Amount	$ 4,096	4,030
Intangible assets with finite lives (amortized), Accumulated Amortization	4,096	4,030
Intangible assets with finite lives (amortized), Net Book Value	$ 0	$ 0

Goodwill and Intangible Asset43

Goodwill and Intangible Assets (Schedule of Goodwill) (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2018USD ($)
Goodwill [Line Items]
Balance, October 1, 2017	$ 1,182,772
Acquisition	4,350
Foreign currency translation adjustment	4,481
Balance, March 31, 2018	1,191,603
Software Products
Goodwill [Line Items]
Balance, October 1, 2017	1,152,917
Acquisition	4,350
Foreign currency translation adjustment	4,368
Balance, March 31, 2018	1,161,635
Professional Services
Goodwill [Line Items]
Balance, October 1, 2017	29,855
Acquisition	0
Foreign currency translation adjustment	113
Balance, March 31, 2018	$ 29,968

Goodwill and Intangible Asset44

Goodwill and Intangible Assets (Amortization of Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 7,895	$ 7,946	$ 15,716	$ 16,013
Cost of license and subscription revenue	6,556	6,389	13,231	12,777
Total amortization expense	$ 14,451	$ 14,335	$ 28,947	$ 28,790

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Sep. 30, 2017
Financial assets:
Cash equivalents			$ 82,291	$ 49,845
Fair value			55,264	50,315
Forward contracts			827	1,163
Financial assets, fair value			138,382	101,323
Financial liabilities:
Contingent consideration related to acquisitions	$ 8,400		6,743	8,400
Forward contracts			4,837	4,347
Liabilities, Fair Value Disclosure, Recurring			11,580	12,747
Business Combination. Contingent Consideration [Roll Forward]
Beginning balance	8,400
Payment of contingent consideration	(3,800)	$ (3,100)
Ending balance	6,743
Level 1
Financial assets:
Cash equivalents			82,291	49,845
Financial assets, fair value			134,941	97,518
Level 2
Financial assets:
Forward contracts			827	1,163
Financial assets, fair value			3,441	3,805
Financial liabilities:
Forward contracts			4,837	4,347
Liabilities, Fair Value Disclosure, Recurring			4,837	4,347
Level 3
Financial liabilities:
Contingent consideration related to acquisitions	8,400	19,570	6,743	8,400
Liabilities, Fair Value Disclosure, Recurring			6,743	8,400
Business Combination. Contingent Consideration [Roll Forward]
Beginning balance	8,400	19,570
Addition to Contingent Consideration	2,100
Change in present value of contingent consideration		148
Payment of contingent consideration	(3,757)	(3,050)
Ending balance	6,743	16,668
Kepware
Financial liabilities:
Contingent consideration related to acquisitions	4,600		4,600
Business Combination. Contingent Consideration [Roll Forward]
Ending balance	4,600
Kepware | Level 3
Financial liabilities:
Contingent consideration related to acquisitions	8,400	17,070	4,643	8,400
Business Combination. Contingent Consideration [Roll Forward]
Beginning balance	8,400	17,070
Addition to Contingent Consideration	0
Change in present value of contingent consideration		148
Payment of contingent consideration	(3,757)	(1,800)
Ending balance	4,643	15,418
Other | Level 3
Financial liabilities:
Contingent consideration related to acquisitions	0		2,100	0
Business Combination. Contingent Consideration [Roll Forward]
Beginning balance	0
Addition to Contingent Consideration	2,100
Payment of contingent consideration	0
Ending balance	$ 2,100
ColdLight | Level 3
Financial liabilities:
Contingent consideration related to acquisitions		2,500
Business Combination. Contingent Consideration [Roll Forward]
Beginning balance		2,500
Change in present value of contingent consideration		0
Payment of contingent consideration		(1,250)
Ending balance		$ 1,250
Certificates of deposit
Financial assets:
Fair value			219	240
Certificates of deposit | Level 2
Financial assets:
Fair value			219	240
Corporate notes/bonds
Financial assets:
Fair value			52,650	47,673
Corporate notes/bonds | Level 1
Financial assets:
Fair value			52,650	47,673
U.S. government agency securities
Financial assets:
Fair value			2,395	2,402
U.S. government agency securities | Level 2
Financial assets:
Fair value			$ 2,395	$ 2,402

Fair Value Measurement (Narrati

Fair Value Measurement (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended		27 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	$ 6,743		$ 6,743	$ 8,400
Payment of contingent consideration	3,800	$ 3,100
Business Combination, Consideration Transferred, Liabilities Incurred	3,200	2,700
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	6,743	16,668	6,743	8,400	$ 19,570
Payment of contingent consideration	3,757	3,050
Level 3 | Accrued Expenses and Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	5,700		5,700
Level 3 | Other Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	1,100		1,100
Kepware
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	4,600		4,600
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	18,000		18,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low	16,900		16,900
payment of contingent consideration			13,400
Kepware | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration related to acquisitions	4,643	15,418	$ 4,643	$ 8,400	$ 17,070
Payment of contingent consideration	$ 3,757	$ 1,800

Marketable Securities (Details)

Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 55,853	$ 50,458
Gross unrealized gains	0	2
Gross unrealized losses	(589)	(145)
Fair value	55,264	50,315
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	30,931	15,494
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(414)	(43)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	24,333	31,287
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(175)	(102)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	55,264	46,781
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(589)	(145)
Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis	22,772	18,274
Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value	22,636	18,244
Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis	33,081	32,184
Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value	32,628	32,071
Available-for-sale Debt Securities, Amortized Cost Basis	55,853	50,458
Available-for-sale Securities, Debt Securities	55,264	50,315
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	220	240
Gross unrealized gains	0	0
Gross unrealized losses	(1)	0
Fair value	219	240
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	219	240
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	219	240
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1)	0
Corporate notes/bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	53,225	47,811
Gross unrealized gains	0	2
Gross unrealized losses	(575)	(140)
Fair value	52,650	47,673
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	30,712	15,254
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(413)	(43)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	21,938	28,885
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(162)	(97)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	52,650	44,139
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(575)	(140)
U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	2,408	2,407
Gross unrealized gains	0	0
Gross unrealized losses	(13)	(5)
Fair value	2,395	2,402
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,395	2,402
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(13)	(5)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,395	2,402
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (13)	$ (5)

Derivative Financial Instrume48

Derivative Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1.8	$ 1	$ 3.2	$ 2.5
Forward Contracts | Not Designated as Hedging Instrument
Derivative, Remaining Maturity	3 months
Forward Contracts | Designated as Hedging Instrument
Derivative, Remaining Maturity	15 months

Derivative Financial Instrume49

Derivative Financial Instruments (Notional Amounts Of Outstanding Forward Contracts) (Details) - Forward Contracts - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Designated as Hedging Instrument
Notional amounts	$ 90,937	$ 101,597
Designated as Hedging Instrument | Euro / U.S. Dollar
Notional amounts	55,744	64,831
Designated as Hedging Instrument | Japanese Yen / U.S. Dollar
Notional amounts	20,077	22,675
Designated as Hedging Instrument | Swedish Krona / U.S. Dollar
Notional amounts	15,116	14,091
Not Designated as Hedging Instrument
Notional amounts	401,511	318,519
Not Designated as Hedging Instrument | Canadian / U.S. Dollar
Notional amounts	7,500	12,809
Not Designated as Hedging Instrument | Swiss Franc / Euro
Notional amounts	0	7,157
Not Designated as Hedging Instrument | Switzerland, Francs
Notional amounts	13,135	605
Not Designated as Hedging Instrument | Chinese Yuan offshore / Euro
Notional amounts	0	10,423
Not Designated as Hedging Instrument | Euro / U.S. Dollar
Notional amounts	320,627	244,000
Not Designated as Hedging Instrument | Japanese Yen / Euro
Notional amounts	18,864	17,694
Not Designated as Hedging Instrument | Israeli Shekel / U.S. Dollar
Notional amounts	6,684	8,820
Not Designated as Hedging Instrument | Japanese Yen / U.S. Dollar
Notional amounts	5,611	3,198
Not Designated as Hedging Instrument | Swedish Krona / U.S. Dollar
Notional amounts	12,619	4,627
Not Designated as Hedging Instrument | Danish Krona / U.S. Dollar
Notional amounts	4,629	1,743
Not Designated as Hedging Instrument | Brazilian Real / U.S. Dollar
Notional amounts	3,117	0
Not Designated as Hedging Instrument | All other
Notional amounts	$ 8,725	$ 7,443

Derivative Financial Instrume50

Derivative Financial Instruments (Derivative Instruments and Hedging Activities Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI-Effective Portion	$ (2,046)	$ (515)	$ (2,959)	$ 2,522
Forward Contracts | Designated as Hedging Instrument | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI-Effective Portion	(2,339)	(589)	(3,382)	2,882
Forward Contracts | Subscription, support and license revenue | Designated as Hedging Instrument | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	(1,728)	567	(2,382)	974
Forward Contracts | Interest income and other expense, net | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Net realized and unrealized gain or (loss) (excluding the underlying foreign currency exposure being hedged)	(2,435)	(238)	(3,022)	8,091
Forward Contracts | Interest income and other expense, net | Designated as Hedging Instrument | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized-Ineffective Portion	$ (16)	$ (4)	$ (35)	$ 5

Derivative Financial Instrume51

Derivative Financial Instruments Derivative Financial Instruments (Gross Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Derivative [Line Items]
Forward contracts	$ 827	$ 1,163
Forward contracts	4,837	4,347
Not Designated as Hedging Instrument | Forward Contracts
Derivative [Line Items]
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	531	623
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	1,718	1,995
Designated as Hedging Instrument | Forward Contracts
Derivative [Line Items]
Foreign Currency Cash Flow Hedge Asset at Fair Value	296	540
Foreign Currency Cash Flow Hedge Liability at Fair Value	3,119	2,352
Other Current Assets [Member] | Forward Contracts
Derivative [Line Items]
Forward contracts	827	1,128
Other Noncurrent Assets | Forward Contracts
Derivative [Line Items]
Forward contracts	0	35
Other Current Liabilities [Member] | Forward Contracts
Derivative [Line Items]
Forward contracts	4,837	4,329
Other Noncurrent Liabilities [Member] | Forward Contracts
Derivative [Line Items]
Forward contracts	$ 0	$ 18

Derivative Financial Instrume52

Derivative Financial Instruments (Offsetting Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amount of Recognized Assets	$ 827
Gross Amounts Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	827	$ 1,163
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(827)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Received	0
Net Amount	$ 0

Derivative Financial Instrume53

Derivative Financial Instruments (Offsetting Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amount of Recognized Liabilities	$ 4,837
Gross Amounts Offset in the Consolidated Balance Sheets	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	4,837	$ 4,347
Gross Amounts Not Offset in the Consolidated Balance Sheets, Financial Instruments	(827)
Gross Amounts Not Offset in the Consolidated Balance Sheets, Cash Collateral Pledged	0
Net Amount	$ 4,010

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended	29 Months Ended
	Mar. 31, 2018USD ($)Segment	Dec. 30, 2017Segment	Apr. 01, 2017USD ($)	Mar. 31, 2018USD ($)	Apr. 01, 2017USD ($)	Sep. 30, 2017Segment	Mar. 31, 2018USD ($)
Number of operating segments | Segment	2	2				3
Number of reportable segments | Segment	2					3
Revenue	$ 307,883		$ 280,040	$ 614,527	$ 566,367
Operating Costs	83,631		81,830	166,589	163,945
Gross margin	224,252		198,210	447,938	402,422
Sales and marketing	98,330		87,777	197,645	178,467
General and administrative	33,353		36,800	68,357	73,495
Restructuring and other charges, net	114		464	219	6,749		$ 84,700
Amortization of acquired intangible assets	7,895		7,946	15,716	16,013
Operating income	22,366		7,513	39,838	12,074
Interest expense	(10,379)		(11,725)	(20,426)	(22,040)
Interest income and other expense, net	441		(3,156)	1,395	(2,407)
Income (loss) before income taxes	11,546		(1,056)	18,017	(7,559)
Operating Segments
Revenue	307,883		280,040	614,527	566,367
Operating Costs	133,215		126,101	267,684	253,964
Gross margin	174,668		153,939	346,843	312,403
Operating Segments | Software Products
Revenue	262,453		234,870	527,643	475,089
Operating Costs	97,306		88,832	196,995	178,871
Gross margin	165,147		146,038	330,648	296,218
Operating Segments | Professional Services
Revenue	45,430		45,170	86,884	91,278
Operating Costs	35,909		37,269	70,689	75,093
Gross margin	9,521		7,901	16,195	16,185
Unallocated
Sales and marketing	93,292		83,647	187,728	170,716
General and administrative	27,382		25,957	54,814	54,007
Restructuring and other charges, net	114		464	219	6,749
Amortization of acquired intangible assets	14,451		14,335	28,947	28,790
Stock-based compensation	17,026		21,577	35,357	39,565
Other unallocated operating expenses	$ 37		$ 446	$ (60)	$ 502

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Mar. 31, 2018	Apr. 01, 2017	Mar. 31, 2018	Apr. 01, 2017	Oct. 01, 2017	Sep. 30, 2017
Income Tax Disclosure [Line Items]
Effective income tax rate		31.00%	(5.00%)	(21.00%)	(36.00%)
Income before income taxes		$ 11,546	$ (1,056)	$ 18,017	$ (7,559)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%	35.00%
Operating Loss Carryforwards, Limitations on Use				0.8
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount		(7,000)	$ (4,000)	$ (9,000)	$ (12,000)
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent				24.50%
Unrecognized tax benefits		14,300		$ 14,300			$ 14,800
Income tax provision upon recognition of unrecognized tax benefit		14,300		14,300
Unrecognized tax benefits that would impact valuation allowance		3,900		3,900
Potentail reduction in unrecognized tax benefits and accrued interest over next 12 months		$ (7,000)		(7,000)
Korea
Income Tax Disclosure [Line Items]
Income tax examination, estimate of possible loss	$ 12,000
US Tax on Undistributed Foreign Earnings [Member]
Income Tax Disclosure [Line Items]
Current Federal, State and Local, Tax Expense (Benefit)				7,100
Net Decrease in Deferred Tax Liability [Member]
Income Tax Disclosure [Line Items]
Deferred Income Tax Expense (Benefit)				$ 14,100
Accounting Standards Update 2016-09 [Member]
Income Tax Disclosure [Line Items]
Windfall Tax Deductions Not Yet Recognized						$ 37,000
Windfall Tax Deductions Not Yet Recognized Offset Valuation Allowance						$ 36,900

Debt (Details)

Debt (Details)	May 15, 2019	Mar. 31, 2018USD ($)	Sep. 30, 2017USD ($)	Jul. 01, 2017USD ($)	Jul. 02, 2016USD ($)	May 31, 2016USD ($)	Sep. 30, 2015bank
Debt Instrument [Line Items]
Senior Notes		$ 500,000,000	$ 500,000,000			$ 500,000,000
Long-term Debt, Gross		648,125,000	718,125,000
debt net of unamortized debt issuance cost		$ 642,837,000	$ 712,406,000
Debt Instrument, Interest Rate, Stated Percentage		6.00%	6.00%			6.00%
Voting interest in domestic subsidiaries pledged against credit facility		100.00%
Voting interest in foreign subsidiaries pledged against credit facility		65.00%
Leverage Ratio, Actual		2.14
Debt Instrument, Covenant Compliance, Senior Debt Leverage Ratio, actual		0.52
Fixed charge coverage ratio, actual		7.51
Line of Credit [Member]
Debt Instrument [Line Items]
Long-term portion of long term debt		$ 148,125,000	$ 218,125,000
Credit facility amount				$ 600,000,000
Additional borrowing capacity on credit facility if agreed to by lenders					$ 500,000,000
Line of Credit Facility, Interest Rate at Period End		3.25%
Component of Base Rate, Basis Spread on Federal Reserve Bank of New York (FRBNY) rate		0.50%
Component of Base Rate, Basis Spread on Adjusted LIBOR		1.00%
Investment limit in foreign subsidiaries		$ 75,000,000
Cash investment limit for acquisition of business		$ 200,000,000
Debt Instrument, Covenant Compliance, Leverage Ratio Four		4.50
Minimum fixed charge coverage ratio allowed under debt covenant		3.50
Debt Instrument, Covenant Compliance, maximum Senior Debt Leverage Ratio after covenant modification trigger event		3
Line of Credit [Member] | Minimum
Debt Instrument [Line Items]
Line of Credit Facility, Variable Interest Rate, Length of Time Between Updates		30 days
Credit facility commitment fees percentage		0.175%
Line of Credit [Member] | Maximum
Debt Instrument [Line Items]
Line of Credit Facility, Variable Interest Rate, Length of Time Between Updates		180 days
Credit facility commitment fees percentage		0.30%
Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Number of Banks in Credit Facility | bank							16
London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member] | Minimum
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member] | Maximum
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Base Rate [Member] | Line of Credit [Member] | Minimum
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.25%
Base Rate [Member] | Line of Credit [Member] | Maximum
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.75%
Scenario, Forecast [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	101.00%
Other Noncurrent Assets | Line of Credit [Member]
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense		$ (1,500,000)	(2,000,000)
Senior Notes [Member]
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense		(5,288,000)	$ (5,719,000)
Debt Instrument, Fair Value Disclosure		$ 526,300,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	1 Months Ended
	Jul. 31, 2016	Mar. 31, 2018	Sep. 30, 2017
Loss Contingencies [Line Items]
Accounts receivable, net of allowance for doubtful accounts of $746 and $1,062 at March 31, 2018 and September 30, 2017, respectively		$ 127,151	$ 152,299
Pending Litigation
Loss Contingencies [Line Items]
Loss contingency accrual		1,200
Korea
Loss Contingencies [Line Items]
Income tax examination, estimate of possible loss	$ 12,000
Minimum | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss		1,200
Minimum | Customer Contracts
Loss Contingencies [Line Items]
Accounts receivable, net of allowance for doubtful accounts of $746 and $1,062 at March 31, 2018 and September 30, 2017, respectively		0
Maximum | Pending Litigation
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss		3,400
Maximum | Customer Contracts
Loss Contingencies [Line Items]
Accounts receivable, net of allowance for doubtful accounts of $746 and $1,062 at March 31, 2018 and September 30, 2017, respectively		$ 17,300

Subsequent Events Subsequent 58

Subsequent Events Subsequent Events (Details) - USD ($)	Apr. 20, 2018	Apr. 30, 2018	Jun. 26, 2018	Mar. 31, 2018	Apr. 01, 2017
Subsequent Event [Line Items]
Borrowings under credit facility				$ 50,000,000	$ 100,000,000
Repayments of Lines of Credit				$ 120,000,000	$ 140,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Borrowings under credit facility		$ 150,000,000
Repayments of Lines of Credit		$ 50,000,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt	$ 100,000,000
Accelerated Share Repurchase Agreement [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Accelerated Share Repurchases, Initial Number of Shares	951,814
Accelerated Share Repurchases, Initial Price Paid Per Share	$ 84.05
Additional Paid-in Capital [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Repurchased and Retired During Period, Value	$ 80,000,000		$ 20,000,000