MACOM Technology Solutions (MTSI) 10-K 15 Nov 17 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Sep. 29, 2017	Nov. 10, 2017	Mar. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 29, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Registrant Name	MACOM Technology Solutions Holdings, Inc.
Entity Central Index Key	1,493,594
Current Fiscal Year End Date	--09-29
Entity Well-known Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Share Outstanding		64,263,802
Entity Public Float			$ 2.1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Current assets:
Cash and cash equivalents	$ 130,104	$ 332,977
Short term investments	84,121	23,776
Accounts receivable (less allowances of $9,410 and $3,279, respectively)	136,096	108,331
Inventories	136,074	114,935
Income tax receivable	18,493	21,607
Assets held for sale	35,571	0
Prepaid and other current assets	22,438	11,318
Total current assets	562,897	612,944
Property and equipment, net	131,019	99,167
Goodwill	313,765	120,024
Intangible assets, net	621,092	259,602
Deferred income taxes	948	89,606
Other long-term assets	7,402	7,208
Total assets	1,637,123	1,188,551
Current liabilities:
Current portion of lease	815	1,152
Current portion long-term debt	6,885	6,051
Accounts payable	47,038	30,579
Accrued liabilities	60,237	54,368
Liabilities held for sale	2,144	0
Total current liabilities	117,119	92,150
Lease payable, less current portion	17,275	2,463
Long-term debt, less current portion	661,471	573,882
Warrant liability	40,775	38,253
Other long-term liabilities	7,937	7,254
Deferred income taxes	15,172	11,765
Total liabilities	859,749	725,767
Stockholders' equity:
Preferred stock, $0.001 par value, 10,000 shares authorized, no shares issued	0	0
Common stock, $0.001 par value, 300,000 shares authorized; 64,279 and 53,709 shares issued and 64,256 and 53,685 shares outstanding as of September 29, 2017 and September 30, 2016, respectively, of which 0 and 3 shares, respectively, are subject to forfeiture	64	54
Treasury Stock, at cost, 23 shares as of both September 29, 2017 and September 30, 2016	(330)	(330)
Accumulated other comprehensive income	2,977	9,039
Additional paid-in capital	1,041,644	551,509
Accumulated deficit	(266,981)	(97,488)
Total stockholders' equity	777,374	462,784
Total liabilities and stockholders' equity	$ 1,637,123	$ 1,188,551

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Statement of Financial Position [Abstract]
Allowances for accounts receivable	$ 9,410	$ 3,279
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	300,000,000	300,000,000
Common stock, issued (in shares)	64,279,000	53,709,000
Common stock, outstanding (in shares)	64,256,000	53,685,000
Common stock, subject to forfeiture (in shares)	200	3,300
Treasury stock (in shares)	23,000	23,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Income Statement [Abstract]
Revenue	$ 698,772	$ 544,338	$ 420,609
Cost of revenue	371,888	262,729	217,019
Gross profit	326,884	281,609	203,590
Operating expenses:
Research and development	147,986	107,698	82,188
Selling, general and administrative	187,886	145,433	110,030
Impairment charges	4,352	11,765	0
Restructuring charges	2,744	3,465	1,280
Total operating expenses	342,968	268,361	193,498
(Loss) income from operations	(16,084)	13,248	10,092
Other (expense) income:
Warrant liability expense	(2,522)	(16,431)	(6,020)
Interest expense	(28,855)	(18,427)	(18,376)
Other (expense) income	(2,044)	39	(1,096)
Total other expense, net	(33,421)	(34,819)	(25,492)
Loss before income taxes	(49,505)	(21,571)	(15,400)
Income tax expense (benefit)	100,911	(17,983)	(9,858)
Loss from continuing operations	(150,416)	(3,588)	(5,542)
(Loss) income from discontinued operations	(19,077)	5,022	54,131
Net (loss) income	$ (169,493)	$ 1,434	$ 48,589
Basic (loss) income per share:
Income (loss) from continuing operations (in USD per share)	$ (2.48)	$ (0.07)	$ (0.11)
Income (loss) from discontinued operations (in USD per share)	(0.31)	0.09	1.06
(Loss) income per share-basic (in USD per share)	(2.79)	0.03	0.95
Diluted (loss) income per share:
Income (loss) from continuing operations (in USD per share)	(2.48)	(0.07)	(0.11)
(Loss) income from discontinued operations (in USD per share)	(0.31)	0.09	1.06
(Loss) income per share-diluted (in USD per share)	$ (2.79)	$ 0.03	$ 0.95
Shares used:
Basic (in shares)	60,704	53,364	51,146
Diluted (in shares)	60,704	53,364	51,146

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (169,493)	$ 1,434	$ 48,589
Unrealized loss on short term investments, net of tax	(63)	(2)	(97)
Foreign currency translation (loss) gain, net of tax	(5,999)	11,320	(918)
Other adjustments, net of tax	0	0	90
Other comprehensive (loss) income, net of tax	(6,062)	11,318	(925)
Total comprehensive (loss) income	$ (175,555)	$ 12,752	$ 47,664

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Additional Paid-In Capital	Accumulated Deficit
Treasury stock (in shares)			(23)
Beginning balance at Oct. 03, 2014	$ 228,567	$ 48	$ (330)	$ (1,354)	$ 377,714	$ (147,511)
Balance (in shares) at Oct. 03, 2014		47,548
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Proceeds from Stock Offering	127,761	$ 5			127,756
Net Proceeds from Stock Offering (in shares)		4,500
Stock option exercises	2,613				2,613
Stock option exercise (in shares)		288
Vesting of restricted common stock and units	1	$ 1
Vesting of restricted common stock and units (in shares)		704
Issuance of common stock pursuant to employee stock purchase plan	2,838				2,838
Issuance of common stock pursuant to employee stock purchase plan (in shares)		176
Shares repurchased for tax withholdings on restricted stock awards	(8,556)	$ (1)			(8,555)
Shares repurchased for tax withholdings on restricted stock awards (in shares)		(258)
Share-based compensation	20,655				20,655
Excess tax benefits	2,990				2,990
Other comprehensive income, net of tax	(925)			(925)
Net (loss) income	48,589					48,589
Ending balance at Oct. 02, 2015	424,533	$ 53	$ (330)	(2,279)	526,011	(98,922)
Balance (in shares) at Oct. 02, 2015		52,958
Treasury stock (in shares)			(23)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises	1,253				1,253
Stock option exercise (in shares)		130
Vesting of restricted common stock and units	1	$ 1
Vesting of restricted common stock and units (in shares)		750
Issuance of common stock pursuant to employee stock purchase plan	4,207				4,207
Issuance of common stock pursuant to employee stock purchase plan (in shares)		154
Shares repurchased for tax withholdings on restricted stock awards	(9,995)				(9,995)
Shares repurchased for tax withholdings on restricted stock awards (in shares)		(283)
Share-based compensation	26,954				26,954
Excess tax benefits	3,079				3,079
Other comprehensive income, net of tax	11,318			11,318
Net (loss) income	1,434					1,434
Ending balance at Sep. 30, 2016	$ 462,784	$ 54	$ (330)	9,039	551,509	(97,488)
Balance (in shares) at Sep. 30, 2016		53,709
Treasury stock (in shares)	23		(23)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises	$ 3,117	$ 0			3,117
Stock option exercise (in shares)	234	234
Vesting of restricted common stock and units		$ 0
Vesting of restricted common stock and units (in shares)		984
Issuance of common stock pursuant to employee stock purchase plan	$ 5,164				5,164
Issuance of common stock pursuant to employee stock purchase plan (in shares)		145
Shares repurchased for tax withholdings on restricted stock awards	(18,534)	$ 0			(18,534)
Shares repurchased for tax withholdings on restricted stock awards (in shares)		(382)
Share-based compensation	36,335				36,335
Stock Issued During Period, Value, Acquisitions	465,082	$ 10			465,072
Payments of Stock Issuance Costs	(1,019)				(1,019)
Stock Issued During Period, Shares, Acquisitions		9,589
Other comprehensive income, net of tax	(6,062)			(6,062)
Net (loss) income	(169,493)					(169,493)
Ending balance at Sep. 29, 2017	$ 777,374	$ 64	$ (330)	$ 2,977	$ 1,041,644	$ (266,981)
Balance (in shares) at Sep. 29, 2017		64,279
Treasury stock (in shares)	23		(23)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (169,493)	$ 1,434	$ 48,589
Adjustments to reconcile net (loss) income to net cash from operating activities (net of acquisitions):
Depreciation and intangible amortization	92,998	70,591	54,708
Share-based compensation	36,335	26,954	19,435
Warrant liability expense	2,522	16,431	6,020
Acquired inventory step-up amortization	44,022	2,061	5,533
Deferred financing costs amortization and write offs	3,373	1,717	1,651
Acquisition prepaid compensation amortization	506	4,457	9,623
Gain from discontinued operations	(25,520)	(7,500)	(63,256)
Deferred income taxes	92,171	(9,936)	7,835
Impairment of assets	4,352	12,955	3,500
Changes in assets held for sale from discontinued operations	218	0	0
Other adjustments, net	2,400	1,083	740
Change in operating assets and liabilities (net of acquisition):
Accounts receivable	(15,754)	(17,209)	(13,089)
Inventories	(4,094)	(24,708)	92
Prepaid expenses and other assets	1,126	(2,412)	3,932
Accounts payable	3,449	(1,075)	(1,858)
Accrued and other liabilities	(15,176)	10,862	(22,679)
Income taxes	7,615	(6,473)	(12,512)
Prepaid compensation	0	0	(14,586)
Net cash from operating activities	61,050	79,232	33,678
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of businesses, net	(270,008)	(85,517)	(208,352)
Purchases of property and equipment	(32,804)	(31,326)	(38,252)
Proceeds from sale of assets	215	0	1,500
Proceeds from sales and maturities of investments	44,555	51,573	0
Purchases of investments	(105,048)	(36,316)	(40,183)
Proceeds associated with discontinued operations	25,520	7,500	81,208
Acquisition of intellectual property	0	(777)	(3,346)
Net cash used in investing activities	(337,570)	(94,863)	(207,425)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from notes payable	96,558	247,625	0
Proceeds from stock option exercises and employee stock purchases	8,281	5,460	5,450
Payments on notes payable	(4,747)	(4,138)	(3,500)
Payments of capital leases and assumed debt	(1,137)	(9,938)	(1,504)
Repurchase of common stock	(18,534)	(9,995)	(8,626)
Proceeds from stock offering, net of issuance costs	0	0	127,761
Proceeds from revolving credit facility	0	0	100,000
Payments on revolving credit facility	0	0	(100,000)
Excess tax benefits	0	3,079	2,990
Other adjustments	(6,768)	(4,739)	(164)
Net cash from financing activities	73,653	227,354	122,407
Foreign currency effect on cash	(6)	(1,058)	(243)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(202,873)	210,665	(51,583)
CASH AND CASH EQUIVALENTS — Beginning of year	332,977	122,312	173,895
CASH AND CASH EQUIVALENTS — End of year	130,104	332,977	122,312
Equity interests issued and issuable	$ 465,082	$ 0	$ 0

Description of Business

Description of Business	12 Months Ended
	Sep. 29, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS MACOM Technology Solutions Holdings, Inc. (the Company) was incorporated in Delaware on March 25, 2009. We are a leading provider of high-performance analog semiconductor solutions that enable next-generation Internet applications, the cloud connected apps economy, and the modern, networked battlefield across the radio frequency (RF), microwave, millimeterwave and lightwave spectrum. We design and manufacture differentiated, high-value products for customers who demand high performance, quality and reliability.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 29, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation, Basis of Presentation and Reclassification —We have one reportable segment, semiconductors and modules. The accompanying consolidated financial statements include our accounts and the accounts of our majority-owned subsidiaries. Certain prior period financial statement amounts, such as debt and leases payable and deferred revenue have been adjusted to conform to currently reported presentations . All intercompany balances and transactions have been eliminated in consolidation. We have a 52 or 53-week fiscal year ending on the Friday closest to the last day of September. The fiscal years 2017 , 2016 and 2015 included 52 weeks. To offset the effect of holidays, for fiscal years in which there are 53 weeks, we typically include the extra week arising in our fiscal years in the first quarter. Use of Estimates —The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities during the reporting periods, the reported amounts of revenue and expenses during the reporting periods and the disclosure of contingent assets and liabilities at the date of the financial statements. On an ongoing basis, we base estimates and assumptions on historical experience, currently available information and various other factors that management believes to be reasonable under the circumstances. Actual results may differ from these estimates and assumptions. Discontinued Operations— In the second quarter of fiscal year 2017, we announced a plan to divest AppliedMicro's compute business (the Compute business). In the fourth quarter of fiscal year 2015, we divested our Automotive business. The operating results of these businesses are reflected in discontinued operations. Foreign Currency Translation and Remeasurement —Our consolidated financial statements are presented in U.S. dollars. While the majority of our foreign operations use the U.S. dollar as the functional currency, the financial statements of our foreign operations for which the functional currency is not the U.S. dollar are translated into U.S. dollars at the exchange rates in effect at the balance sheet dates (for assets and liabilities) and at average exchange rates (for revenue and expenses). The unrealized translation gains and losses on the net investment in these foreign operations are accumulated as a component of other comprehensive income (loss). The financial statements of our foreign operations where the functional currency is the U.S. dollar, but where the underlying transactions are transacted in a different currency, are remeasured at the exchange rate in effect at the balance sheet date with respect to monetary assets and liabilities. Nonmonetary assets and liabilities, such as inventories and property and equipment and related statements of operations accounts, such as cost of revenue and depreciation, are remeasured at historical exchange rates. Revenue and expenses, other than cost of revenue, amortization and depreciation, are translated at the average exchange rate for the period in which the transaction occurred. The net gains and losses on foreign currency remeasurement are reflected in selling, general and administrative expense in the accompanying consolidated statements of operations. Net foreign exchange transaction gains and losses for all periods presented were immaterial. Cash and Cash Equivalents —Cash equivalents are primarily composed of short-term, highly-liquid instruments with an original maturity of three months or less and consist primarily of money market funds and commercial paper. Investments —We classify our investments as available-for-sale. Our investments classified as available-for-sale are recorded at fair value based upon third party pricing at period end. Unrealized gains and losses that are deemed temporary in nature are recorded in accumulated other comprehensive income and loss as a separate component of stockholders’ equity. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums and discounts are amortized (accreted) over the life of the related security as an adjustment to its yield. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of investments sold. Inventories —Inventories are stated at the lower of cost or market. We use a combination of standard cost and moving weighted-average cost methodologies to determine the cost basis for our inventories, approximating a first-in, first-out basis. The standard cost of finished goods and work-in-process inventory is composed of material, labor and manufacturing overhead, which approximates actual cost. In addition to stating inventory at the lower of cost or market, we also evaluate inventory each reporting period for excess quantities and obsolescence, establishing reserves when necessary based upon historical experience, assessment of economic conditions and expected demand. Once recorded, these reserves are considered permanent adjustments to the carrying value of inventory. Property and Equipment —Property and equipment are stated at cost, less accumulated depreciation and amortization. Expenditures for maintenance and repairs are charged to expense as incurred, whereas major improvements that significantly extend the useful life of the assets are capitalized as additions to property and equipment. Property and equipment are depreciated or amortized using the straight-line method over the following estimated useful lives: Asset Classification Estimated Useful Life In Years Buildings and improvements 20 – 40 Machinery and equipment 2 – 7 Computer equipment and software 2 – 5 Furniture and fixtures 7 – 10 Leasehold improvements Shorter of useful life or term of lease Goodwill and Indefinite-Lived Intangible Assets —We have goodwill and certain intangible assets with indefinite lives which are not subject to amortization; these are reviewed for impairment annually as of the end of our August fiscal month end and more frequently if events or changes in circumstances indicate that the assets may be impaired. For our assessment of goodwill impairment, we compare the carrying value of the reporting unit to the fair value of the Company. For our assessment of in-service indefinite-lived assets we compare the carrying value of the asset to the estimated fair value of the asset. For indefinite-lived assets not in service, such as in-process research and development, we perform both qualitative and quantitative assessments using an assumption of "more likely than not" to determine if there are any impairment indicators. If impairment exists, a loss is recorded to write down the value of the assets to their implied fair values. During the fiscal year ended September 29, 2017 , we recorded impairment charges of $4.4 million related to indefinite-lived intangible assets. S ee Note 16 - Intangible Assets , for further detail of these impairment charges. There were no significant expenses related to abandoned in-process research and development projects in any prior period presented. Impairment of Long-Lived Assets —Long-lived assets include property and equipment and definite-lived intangible assets subject to amortization. We evaluate long-lived assets for recoverability when events or changes in circumstances indicate that their carrying amounts may not be recoverable. Circumstances which could trigger a review include, but are not limited to, significant decreases in the market price of the asset or asset group, significant adverse changes in the business climate or legal factors, the accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of the asset, current period cash flow or operating losses combined with a history of losses or a forecast of continuing losses associated with the use of the asset and a current expectation that the asset will more likely than not, be sold or disposed of significantly before the end of its previously estimated useful life. In evaluating a long-lived asset for recoverability, we estimate the undiscounted cash flows expected to result from our use and eventual disposition of the asset. If the sum of the expected undiscounted cash flows is less than the carrying amount of the asset, an impairment loss, equal to the excess of the carrying amount over the fair value of the asset, is recognized. In fiscal year 2016 we recorded impairment charges of $ 13.8 million related to our strategic decision to exit a product line and end programs associated with our GaN-on Silicon Carbide (GaN-on-SiC) license and technology transfer. There were no impairments of definite life long-lived assets in any other periods presented. Intangible assets related to in-process research and development acquired are not amortized until the underlying asset begins revenue-generating activity, at which time it is amortized over its estimated useful life. Intangibles related to abandoned in-process research and development projects are expensed in the period the project is abandoned. Other Intangible Assets —Our other intangible assets, including acquired technology and customer relationships, are definite-lived assets and are subject to amortization. We amortize definite-lived assets over their estimated useful lives, which range from five to fourteen years, generally based on the pattern over which we expect to receive the economic benefit from these assets. Revenue Recognition —We recognize revenue when: (i) persuasive evidence of an arrangement exists; (ii) delivery or services have been rendered; (iii) the price is fixed or determinable; and (iv) collectability is reasonably assured. We recognize revenue with the transfer of title and risk of loss and provide for reserves for returns and other allowances. We generally do not provide customers other than distributors the right to return product, with the exception of warranty related matters. Shipping and handling fees billed to customers are recorded as revenue while the related costs are classified as a component cost of revenue. We provide warranties for certain products and accrue the costs of warranty claims in the period the related revenue is recorded. Prior to fiscal year 2015, we had concluded that we had insufficient information as well as limited experience in estimating the effect of the right of distributors to return product and price protection and, accordingly, used the sell through approach of revenue recognition. Under this approach, we would recognize revenue from sales after the distributor resold the product to its end customer (the sell through basis). After concluding an extensive three year study of distributor related transactions, we completed an evaluation of our revenue recognition policy and concluded that it was appropriate to recognize revenue to distributors at the time of shipment to the distributor (sell-in basis). During fiscal year 2015, we concluded that we had sufficient data to predict future price adjustments from distributors and had a basis of being able to reasonably estimate these future price adjustments. Accordingly, on a consolidated basis, revenue from distribution customers was impacted by a change in estimate. Revenues from distributors accounted for approximately 10-15% of total consolidated revenue at that time. The terms of certain agreements with distribution customers provide for rights of return and compensation credits until such time as our products are sold by the distributors to their end customers. We have agreements with some distribution customers for various programs, including compensation, volume-based pricing, obsolete inventory, new products and stock rotation. Sales to these distribution customers, as well as the existence of compensation programs, are in accordance with terms set forth in written agreements with these distribution customers. In general, credits allowed under these programs are capped based upon individual distributor agreements. We record charges associated with these programs as a reduction of revenue at the time of sale with a corresponding adjustment to accounts receivable based upon historical activity. Our policy is to use a 12 months rolling historical experience rate and an estimated general reserve percentage in order to estimate the necessary allowance to be recorded. During the fiscal year ended October 2, 2015, we recorded corresponding adjustments related to this change in estimate to recognize previously deferred revenues. The full-year impact of this change in estimate resulted in additional revenue of $17.4 million and a net income of $7.7 million , or $0.15 earnings per share during fiscal year 2015. We also established a new reserve of $6.0 million for the fiscal year ended October 2, 2015 related to future rebates and returns under various programs associated with our distributor agreements. Research and Development Costs —Costs incurred in the research and development of products are expensed as incurred. Income Taxes —Deferred tax assets and liabilities are recognized based on temporary differences between the financial reporting and income tax bases of assets and liabilities, using rates anticipated to be in effect when such temporary differences reverse. A valuation allowance against net deferred tax assets is required if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. We provide reserves for potential payments of tax to various tax authorities related to uncertain tax positions and other issues. Reserves are based on a determination of whether and how much of a tax benefit is taken by us in our tax filings or positions that are more likely than not to be realized following an examination by taxing authorities. We recognize the financial statement benefit of an uncertain tax position only after considering the probability that a tax authority would sustain the position in an examination. For tax positions meeting a “more-likely-than-not” threshold, the amount recognized in the financial statements is the benefit expected to be realized upon settlement with the tax authority. For tax positions not meeting the threshold, no financial statement benefit is recognized. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of income tax expense. Earnings Per Share —Basic net (loss) income per share is computed by dividing net (loss) income by the weighted-average number of common shares outstanding during the period, excluding the dilutive effect of common stock equivalents. Diluted net income (loss) per share reflects the dilutive effect of common stock equivalents, such as stock options, warrants and restricted stock units, using the treasury stock method. Fair Value Measurements —Financial assets and liabilities are measured at fair value. Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability at the measurement date under current market conditions in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, we group financial assets and liabilities in a three-tier fair value hierarchy, according to the inputs used in measuring fair value as follows: Level 1—observable inputs such as quoted prices in active markets for identical assets and liabilities; Level 2—inputs other than quoted prices in active markets that are observable either directly or indirectly, such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical assets and liabilities in markets that are not active and model-based valuation techniques for which significant assumptions are observable in active markets; and, Level 3—unobservable inputs for which there is little or no market data, requiring us to develop our own assumptions for model-based valuation techniques. This hierarchy requires us to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Money market funds are actively traded and consist of highly liquid investments with original maturities of 90 days or less. They are measured at their net asset value (NAV) and classified as Level 1. Corporate and agency bonds and commercial paper are categorized as Level 2 assets except where sufficient quoted prices exist in active markets, in which case such securities are categorized as Level 1 assets. These securities are valued using third-party pricing services. These services may use, for example, model-based pricing methods that utilize observable market data as inputs. We generally use quoted prices for recent trading activity of assets with similar characteristics to the debt security or bond being valued. The securities and bonds priced using such methods are generally classified as Level 2. Broker dealer bids or quotes on securities with similar characteristics may also be used. The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to the short-term nature of these assets and liabilities. Contingent Consideration —We estimate and record at the acquisition date, the fair value of contingent consideration making up part of the purchase price consideration for acquisitions. Additionally, at each reporting period, we estimate the change in the fair value of contingent consideration and any change in fair value is recognized in the consolidated statements of operations. We estimate the fair value of contingent consideration by discounting the associated expected cash flows, using a probability-weighted, discounted cash flow model. The estimate of the fair value of contingent consideration requires subjective assumptions to be made regarding future operating results, discount rates and probabilities assigned to various potential operating result scenarios. Share-Based Compensation —We account for all share-based compensation arrangements using the fair value method. We recognize compensation expense over the requisite service period of the award, which is generally the vesting period, using the straight-line method and providing that the minimum amount of compensation recorded is equal to the vested portion of the award. We record the expense in the consolidated statements of operations in the same manner in which the award recipients’ salary costs are classified. For restricted stock awards with service conditions we use the closing stock price on the date of grant to estimate the fair value of the awards. We use the Black-Scholes option-pricing model to estimate the fair value of stock options with service and performance conditions, inclusive of assumptions for risk-free interest rates, dividends, expected terms and estimated volatility. We derive the risk-free interest rate assumption from the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to the expected term of the award being valued. We base the assumed dividend yield on its expectation of not paying dividends in the foreseeable future. We calculate the weighted-average expected term of the options using the simplified method, which is a method of applying a formula that uses the vesting term and the contractual term to compute the expected term of a stock option. The decision to use the simplified method is based on a lack of relevant historical data, due to our limited operating experience. In addition, due to our limited historical data, we incorporate the historical volatility of comparable companies with publicly available share prices to determine estimated volatility. The accounting for share-based compensation requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Share-based awards that are settled in cash are recorded as liabilities. The measurement of the liability and compensation cost for these awards is based on the fair value of the award, and is recorded in operating income over the award’s vesting period. Changes in our payment obligation prior to the settlement date of a stock-based award are recorded as compensation cost in operating income in the period of the change. The final payment amount for such awards is established on the date of the exercise of the award by the employee. Guarantees and Indemnification Obligations —We enter into agreements in the ordinary course of business with, among others, customers, distributors and original equipment manufacturers (OEM). Most of these agreements require us to indemnify the other party against third-party claims alleging that a Company product infringes a patent and/or copyright. Certain agreements in which we grant limited licenses to Company intellectual property require us to indemnify the other party against third-party claims alleging that the use of the licensed intellectual property infringes a third-party's intellectual property. Certain of these agreements require us to indemnify the other party against certain claims relating to property damage, personal injury or the acts or omissions, its employees, agents or representatives. In addition, from time to time, we have made certain guarantees in the form of warranties regarding the performance of Company products to customers. We have agreements with certain vendors, creditors, lessors and service providers pursuant to which we have agreed to indemnify the other party for specified matters, such as acts and omissions, its employees, agents or representatives. We have procurement or license agreements with respect to technology used in our products and agreements in which we obtain rights to a product from an OEM. Under some of these agreements, we have agreed to indemnify the supplier for certain claims that may be brought against such party with respect to our acts or omissions relating to the supplied products or technologies. Our certificate of incorporation and agreements with certain of our directors and officers and certain of our subsidiaries’ directors and officers provide them indemnification rights, to the extent legally permissible, against liabilities incurred by them in connection with legal actions in which they may become involved by reason of their service as a director or officer. As a matter of practice, we have maintained director and officer liability insurance coverage, including coverage for directors and officers of acquired companies. We have not experienced any losses related to these indemnification obligations in any period presented and no claims with respect thereto were outstanding as of September 29, 2017 and September 30, 2016 . We do not expect significant claims related to these indemnification obligations and, consequently, have concluded that the fair value of these obligations is negligible. No liabilities related to indemnification liabilities have been established. Recent Accounting Pronouncements —In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers: Deferral of the Effective Date , which delayed the effective date of the new standard from January 1, 2017 to January 1, 2018. The FASB also agreed to allow entities to choose to adopt the standard as of the original effective date. We are still in the process of completing our gap analysis on the impact of this guidance. At this time, with the consideration that we currently recognize distributor revenue based on sell-in accounting, we do not expect the adoption of Topic 606 to have a material impact on our financial position and results of operations. The standard permits the use of either the retrospective or cumulative effect transition method, and we are currently evaluating the method of adoption. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern , which provides guidance on management's responsibility to assess whether there is substantial doubt about a company's ability to continue as a going concern. The guidance is effective for annual periods ending after December 15, 2016 and interim periods thereafter. As of September 29, 2017, we have adopted this guidance and performed the required assessment which did not have a significant impact on our consolidated financial statement disclosures. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Liabilities . This update makes amendments to the guidance in U.S. GAAP on the classification and measurement of financial instruments. The new standard significantly revises an entity's accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. It also amends certain disclosure requirements associated with the fair value of financial instruments. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases , which increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Certain qualitative and quantitative disclosures are required, as well as a retrospective recognition and measurement of impacted leases. The new guidance is effective for fiscal years and interim periods within those years beginning after December 15, 2018, with early adoption permitted. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures and we anticipate that this new guidance will materially impact our financial statements as we have a significant number of operating leases. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. Early adoption is permitted and the updated standard must be adopted no later than our fiscal first quarter of fiscal year 2018. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments . This update amends the guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For available for sale debt securities, credit losses should be measured in a manner similar to current GAAP; however, this update will require that credit losses be presented as an allowance rather than as a write-down. ASU 2016-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments . This update addresses debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory . This update amends the guidance on recognizing the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendment eliminates the exception for an intra entity transfer of an asset other than inventory. ASU 2016-16 is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures.

Acquisitions

Acquisitions	12 Months Ended
	Sep. 29, 2017
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS Acquisition of Applied Micro Circuits Corporation— On January 26, 2017, we completed the acquisition of Applied Micro Circuits Corporation (AppliedMicro), a global provider of silicon solutions for next-generation cloud infrastructure and Cloud Data Centers, as well as connectivity products for edge, metro and long-haul communications equipment (the AppliedMicro Acquisition). We acquired AppliedMicro in order to expand our business in enterprise and Cloud Data Center applications. In connection with the AppliedMicro Acquisition, we acquired all of the outstanding common stock of AppliedMicro for total consideration of $695.4 million , which included cash paid of $287.1 million , less $56.8 million of cash acquired, and equity issued at a fair value of $465.1 million . In conjunction with the equity issued, we granted vested out-of-the-money stock options and unvested restricted stock units to replace outstanding vested out-of-the-money stock options and unvested restricted stock units of AppliedMicro. The total fair value of granted vested out-of-money stock options and unvested restricted stock units was $14.5 million , of which $9.3 million was attributable to pre-combination service and was included in the total consideration transferred. We funded the AppliedMicro Acquisition with cash on hand and short term investments. For the fiscal year ended September 29, 2017 , we recorded transaction costs of $11.9 million . We recorded transaction costs related to the acquisition in selling, general and administrative expense, except for $1.0 million related to equity issuance costs that were recorded to additional paid in capital. The AppliedMicro Acquisition was accounted for as a stock purchase and the operations of AppliedMicro have been included in our consolidated financial statements since the date of acquisition. We recognized the AppliedMicro assets acquired and liabilities assumed based upon the fair value of such assets and liabilities measured as of the date of acquisition. The aggregate purchase price for AppliedMicro has been allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair value at the date of acquisition. The excess of the purchase price over the fair value of the acquired net assets represents cost and revenue synergies specific to the Company, as well as non-capitalizable intangible assets, such as the employee workforce acquired, and has been allocated to goodwill, none of which will be tax deductible. The purchase accounting is preliminary and subject to completion including certain fair value measurements, particularly the finalization of the valuation assessment of the acquired tangible and intangible assets. The adjustments arising from the completion of the outstanding matters may materially affect the preliminary purchase accounting. In connection with the acquisition of AppliedMicro, we announced a plan to divest a portion of AppliedMicro's business specifically related to its Compute business. Accordingly, these assets and liabilities are accounted for as discontinued operations and classified as assets and liabilities held for sale. The following table summarizes the total estimated acquisition consideration (in thousands): Cash consideration paid to AppliedMicro common stockholders $ 287,060 Common stock issued (9,544,125 shares of our common stock at $47.53 per share) 453,632 Equity consideration for vested "in-the-money" stock options and unvested restricted stock units 2,143 Fair value of the replacement equity awards attributable to pre-acquisition service 9,307 Total consideration paid, less cash acquired $ 752,142 The preliminary allocation of purchase price as of September 29, 2017 is as follows (in thousands): Preliminary Allocation Allocation Adjustments Adjusted Allocation March 31, 2017 September 29, 2017 Current assets $ 70,338 $ 96 $ 70,434 Intangible assets 410,348 2,500 412,848 Assets held for sale 32,458 8,486 40,944 Other assets 13,504 (3,704 ) 9,800 Total assets acquired 526,648 7,378 534,026 Liabilities held for sale 4,444 — 4,444 Other liabilities 17,890 (263 ) 17,627 Total liabilities assumed 22,334 (263 ) 22,071 Net assets acquired 504,314 7,641 511,955 Consideration: Cash paid upon closing 230,298 — 230,298 Common stock issued 455,775 — 455,775 Equity instruments issued 9,307 — 9,307 Total consideration $ 695,380 $ — $ 695,380 Goodwill $ 191,066 $ (7,641 ) $ 183,425 The components of the acquired intangible assets were as follows (in thousands): Included In Assets Held For Sale Included In Retained Business Useful Lives (Years) Developed technology $ 9,600 $ 78,448 7 years Customer relationships — 334,400 14 years $ 9,600 $ 412,848 The overall weighted-average life of the identified intangible assets acquired in the AppliedMicro Acquisition is estimated to be 12.7 years and the assets are being amortized over their estimated useful lives based upon the pattern over which we expect to receive the economic benefit from these assets. The following is a summary of AppliedMicro revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 29, 2017 (in thousands): Amount Revenue $ 110,117 Loss from continuing operations (27,222 ) Loss from discontinued operations (44,599 ) The pro forma statements of operations data for the fiscal years ended September 29, 2017 and September 30, 2016 , below, give effect to the AppliedMicro Acquisition, described above, as if it had occurred at October 2, 2015. These amounts have been calculated after applying our accounting policies and adjusting the results of AppliedMicro to reflect: transaction costs, retention compensation expense, the impact of the step-up to the value of acquired inventory, as well as the additional intangible amortization that would have been charged assuming the fair value adjustments had been applied and incurred since October 2, 2015. This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 29, 2017 September 30, 2016 Revenue $ 755,728 $ 707,299 Loss from continuing operations (104,828 ) (53,613 ) Loss from discontinued operations (43,734 ) (72,730 ) Acquisition of Assets of Picometrix LLC— On August 9, 2017, we completed the acquisition of certain assets of Picometrix LLC (Picometrix), a supplier of optical-to-electrical converters for Cloud Data Center infrastructure (the Picometrix Acquisition). We acquired Picometrix in order to expand our business in enterprise and Cloud Data Center applications. The purchase consideration was $33.5 million , comprised of an upfront cash payment of $29.5 million , and $4.0 million placed in escrow for potential satisfaction of certain indemnification obligations that may arise from the closing date through December 15, 2018. For the fiscal year ended September 29, 2017 , we recorded transaction costs of $0.2 million in selling, general and administrative expense. The Picometrix Acquisition was accounted for as an asset purchase, and the operations of Picometrix have been included in our consolidated financial statements since the date of acquisition. We recognized the Picometrix assets acquired based upon the fair value of such assets measured as of the date of acquisition. The aggregate purchase price for the Picometrix assets has been allocated to the tangible and identifiable intangible assets acquired based on their estimated fair value at the date of acquisition. The excess of the purchase price over the fair value of the acquired assets represents cost and revenue synergies specific to the Company, as well as non-capitalizable intangible assets, such as the employee workforce acquired, and has been allocated to goodwill, all of which will be tax deductible. The purchase accounting is preliminary and subject to completion including certain fair value measurements, particularly the finalization of the valuation assessment of the acquired tangible and intangible assets. The adjustments arising from the completion of the outstanding matters may materially affect the preliminary purchase accounting. The preliminary allocation of purchase price as of September 29, 2017 is as follows (in thousands): Preliminary Allocation September 29, 2017 Current assets $ 7,375 Intangible assets 19,000 Other assets 3,301 Total assets acquired 29,676 Current liabilities 2,169 Other liabilities 190 Total liabilities assumed 2,359 Net assets acquired 27,317 Consideration: Cash paid upon closing, net of cash acquired 33,500 Goodwill $ 6,183 The pro forma financial information for fiscal year 2017 , including revenue and net income, is immaterial, and has not been separately presented. Other Acquisitions — On July 31, 2017, we completed the acquisition of certain assets of Antario Technologies, Inc. (Antario) a privately-held company based in Taiwan and in California. The total cash consideration was approximately $5.8 million , of which $4.8 million was paid upon closing, and approximately $1.0 million was withheld for potential satisfaction of certain indemnification obligations that may arise from the closing date through July 31, 2018. We have recorded a preliminary allocation of the purchase price for the assets of Antario, which resulted in goodwill of $1.6 million and intangible assets, including acquired technology and customer relationships, of $4.1 million . The Antario transaction was accounted for as an asset purchase and the operations have been included in our consolidated financial statements since the acquisition date. Pro forma financial disclosures are not presented herein as the financial results of Antario are considered immaterial. On May 26, 2017, we completed the acquisition of Triple Play Communications Corporation (TPC) a privately-held company based in Melbourne, Florida. The total cash consideration was approximately $2.6 million , of which $2.2 million was paid upon closing, and approximately $0.4 million was withheld for potential satisfaction of certain indemnification obligations from the closing date through November 23, 2018. We have recorded a preliminary allocation of the purchase price for TPC, which resulted in goodwill of $3.9 million and intangible assets, including customer relationships, of $0.2 million . TPC was accounted for as a stock purchase and the operations have been included in our consolidated financial statements since the acquisition date. Pro forma financial disclosures are not presented herein as the financial results of TPC are considered immaterial. Acquisition of FiBest Limited — On December 9, 2015, we completed the acquisition of FiBest Limited (FiBest) a Japan-based merchant market component supplier of optical sub-assemblies (FiBest Acquisition). We acquired FiBest to expand our position in optical networking components. In connection with the FiBest Acquisition, all of the outstanding equity interests (including outstanding options) of FiBest were exchanged for aggregate consideration of $ 59.1 million including cash of $ 47.5 million and assumed debt of $ 11.6 million . We funded the FiBest Acquisition with cash on hand. There were no transaction costs recorded for the fiscal year ended September 29, 2017. For the fiscal year ended September 30, 2016, we recorded transaction costs of $2.7 million as selling, general and administrative expense related to this acquisition. The FiBest Acquisition was accounted for as a stock purchase and the operations of FiBest have been included in our consolidated financial statements since the date of acquisition. We recognized the FiBest assets acquired and liabilities assumed based upon the fair value of such assets and liabilities measured as of the date of acquisition. The aggregate purchase price for FiBest is being allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The excess of the purchase price over the fair value of the acquired net assets represents cost and revenue synergies specific to the Company, as well as non-capitalizable intangible assets, such as the employee workforce acquired, and has been allocated to goodwill, none of which will be tax deductible. During the fiscal quarter ended December 30, 2016, we recorded an adjustment of $0.2 million primarily related to other liabilities and an adjustment of the deferred tax liability associated with the FiBest Acquisition. We finalized our allocation of purchase price during the fiscal quarter ended December 30, 2016. The final allocation of purchase price as of December 30, 2016, is as follows (in thousands): Preliminary Allocation as of September 30, 2016 Allocation Adjustments Final Allocation Current assets $ 10,445 $ — $ 10,445 Intangible assets 45,650 — 45,650 Other assets 3,317 — 3,317 Total assets acquired 59,412 — 59,412 Debt 11,627 — 11,627 Deferred income taxes 11,658 (106 ) 11,552 Other liabilities 3,968 326 4,294 Total liabilities assumed 27,253 220 27,473 Net assets acquired 32,159 (220 ) 31,939 Consideration: Cash paid upon closing, net of cash acquired 47,517 — 47,517 Goodwill $ 15,358 $ 220 $ 15,578 The components of the acquired intangible assets on a preliminary basis were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 9,400 7 Customer relationships 36,250 10 $ 45,650 The overall weighted-average life of the identified intangible assets acquired in the FiBest Acquisition is estimated to be 9.4 years and the assets are being amortized over their estimated useful lives based upon the pattern over which we expect to receive the economic benefit from these assets. The following is a summary of FiBest revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 30, 2016 (in thousands): Amount Revenue $ 30,540 Loss before income taxes (4,616 ) Unaudited Supplemental Pro Forma Data— The pro forma statements of operations data for the fiscal year ended September 30, 2016 and October 2, 2015 below give effect to the FiBest Acquisition, described above, as if it had occurred at October 4, 2014. These amounts have been calculated after applying our accounting policies and adjusting the results of FiBest to reflect; transaction costs, retention compensation expense, the impact of the step-up to the value of acquired inventory, as well as the additional intangible amortization that would have been charged assuming the fair value adjustments had been applied and incurred since October 4, 2014. This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 30, 2016 October 2, 2015 Revenue $ 551,964 $ 444,991 Net (loss) income (3,324 ) 36,715 Acquisition of Aeroflex/Metelics Inc. — On December 14, 2015, we acquired Aeroflex/Metelics, Inc. (Metelics), a diode supplier for aggregate cash consideration of $37.1 million , subject to customary working capital and other adjustments (Metelics Acquisition). We acquired Metelics to expand our diode business. We funded the acquisition with cash on hand. The Metelics Acquisition was accounted for as a stock purchase and the operations of Metelics have been included in our consolidated financial statements since the date of acquisition. For the fiscal year ended September 29, 2017 , we recorded no transaction costs related to this acquisition. For the fiscal year ended September 30, 2016 , we recorded transaction costs of $0.5 million as selling, general and administrative expenses related to this acquisition. We recognized the Metelics assets acquired and liabilities assumed based upon the fair value of such assets and liabilities measured as of the date of acquisition. The aggregate purchase price for Metelics is being allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The excess of the purchase price over the fair value of the acquired net assets represents cost and revenue synergies specific to the Company, as well as non-capitalizable intangible assets, such as the employee workforce acquired, and has been allocated to goodwill, which will be tax deductible due to a 338(h)(10) election. We finalized our allocation of purchase price during the fiscal quarter ended December 30, 2016. The final allocation of purchase price as of December 30, 2016, is as follows (in thousands): Preliminary Allocation as of September 30, 2016 Allocation Adjustments Final Allocation Current assets $ 12,614 $ — $ 12,614 Intangible assets 20,900 — 20,900 Other assets 3,089 — 3,089 Total assets acquired 36,603 — 36,603 Other liabilities 7,201 — 7,201 Total liabilities assumed 7,201 — 7,201 Net assets acquired 29,402 — 29,402 Consideration: Cash paid upon closing, net of cash acquired 37,125 — 37,125 Goodwill $ 7,723 $ — $ 7,723 The components of the acquired intangible assets on a preliminary basis were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 1,000 7 Customer relationships 19,900 10 $ 20,900 The overall weighted-average life of the identified intangible assets acquired in the Metelics Acquisition is estimated to be 9.9 years and the assets are being amortized over their estimated useful lives based upon the pattern over which we expect to receive the economic benefit from these assets. The following is a summary of Metelics revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 30, 2016 (in thousands): Amount Revenue $ 33,552 Income before income taxes 3,372 Unaudited Supplemental Pro Forma Data— The pro forma statements of operations data for the fiscal year ended September 30, 2016 and October 2, 2015, below, give effect to the Metelics Acquisition, described above, as if it had occurred at October 4, 2014. These amounts have been calculated after applying our accounting policies and adjusting the results of Metelics to reflect the transaction costs, the impact of the step-up to the value of acquired inventory, as well as, the additional intangible amortization that would have been charged assuming the fair value adjustments had been applied and incurred since October 4, 2014. This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 30, 2016 October 2, 2015 Revenue $ 553,174 $ 459,048 Net income 1,183 45,107 Acquisition of BinOptics Corporation — On December 15, 2014 , we completed the acquisition of BinOptics Corporation (BinOptics), a supplier of high-performance photonic semiconductor products (BinOptics Acquisition). In accordance with the related Agreement and Plan of Merger, all of the outstanding equity interests (including outstanding warrants) of BinOptics were exchanged for aggregate consideration of approximately $208.4 million in cash. In addition we paid $14.6 million as part of a related retention escrow agreement designed to retain certain BinOptics employees. This $14.6 million was included in the terms of the purchase agreement and has been accounted for as a post-closing prepaid expense. We funded the BinOptics Acquisition with a combination of cash on hand and the incurrence of $100.0 million of additional borrowings under our existing Revolving Facility. For the fiscal year ended October 2, 2015, we recorded transaction costs of approximately $4.2 million related to the BinOptics Acquisition in selling, general and administrative expense in the accompanying consolidated statements of operations. The BinOptics Acquisition was accounted for as a purchase and the operations of BinOptics have been included in our consolidated financial statements since the date of acquisition. We have recognized BinOptics' assets acquired and liabilities assumed based upon the fair value of such assets and liabilities measured as of the date of acquisition. The aggregate purchase price for BinOptics has been allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The excess of the purchase price over the fair value of the acquired net assets represents cost and revenue synergies specific to the Company, as well as non-capitalizable intangible assets, such as the employee workforce acquired, and has been allocated to goodwill, none of which is tax deductible. We finalized our allocation of purchase price during the first quarter of fiscal year 2016. The final allocation of purchase price as of January 1, 2016, was as follows (in thousands): Preliminary Allocation as of October 2, 2015 Allocation Adjustments Final Allocation Current assets $ 23,674 $ (1,100 ) $ 22,574 Intangible assets 136,900 400 137,300 Other assets 9,194 — 9,194 Total assets acquired 169,768 (700 ) 169,068 Debt 2,535 — 2,535 Deferred income taxes 33,345 99 33,444 Other liabilities 13,106 — 13,106 Total liabilities assumed 48,986 99 49,085 Net assets acquired 120,782 (799 ) 119,983 Consideration: Cash paid upon closing, net of cash acquired 208,352 — 208,352 Goodwill $ 87,570 $ 799 $ 88,369 The components of the acquired intangible assets were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 17,500 7 Customer relationships 119,800 10 $ 137,300 The overall weighted-average life of the identified intangible assets acquired in the BinOptics Acquisition is estimated to be 9.6 years and the assets are being amortized over their estimated useful lives based upon the pattern over which we expect to receive the economic benefit from these assets. The following is a summary of BinOptics revenue and earnings included in our consolidated statements of operations for the fiscal year ended October 2, 2015 (in thousands): Fiscal Year Ended October 2, 2015 Revenue $ 61,549 Income before income taxes 354 Unaudited Supplemental Pro Forma Data— The pro forma statements of operations data for the fiscal year ended October 2, 2015, below, give effect to the BinOptics Acquisition, described above, as if it had occurred at September 28, 2013. These amounts have been calculated after applying our accounting policies and adjusting the results of BinOptics to reflect the additional depreciation and amortization that would have been charged assuming the fair value adjustments to property, plant and equipment and intangible assets and additional interest expense on acquisition-related borrowings had been applied and incurred since September 28, 2013. This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. October 2, 2015 Revenue $ 428,440 Net income from continuing operations (3,489 )

Investments

Investments	12 Months Ended
	Sep. 29, 2017
Investments, Debt and Equity Securities [Abstract]
Investments	. INVESTMENTS All investments are short term in nature and are invested in corporate bonds, commercial paper and agency bonds, and are classified as available-for-sale. The amortized cost, gross unrealized holding gains or losses and fair value of our available-for-sale investments by major investments type as of September 29, 2017 and September 30, 2016 are summarized in the tables below (in thousands): September 29, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Corporate bonds $ 26,366 $ 10 $ (166 ) $ 26,210 Commercial paper 57,943 4 (36 ) 57,911 Total investments $ 84,309 $ 14 $ (202 ) $ 84,121 September 30, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Corporate bonds $ 14,894 $ 9 $ (104 ) $ 14,799 Commercial paper 2,978 — (3 ) 2,975 Agency bonds 6,004 1 (3 ) 6,002 Total investments $ 23,876 $ 10 $ (110 ) $ 23,776 The contractual maturities of available-for-sale investments were as follows (in thousands): September 29, 2017 Less than 1 year $ 60,433 Over 1 year 23,688 Total investments $ 84,121 Available-for-sale investments are reported at fair value and as such, their associated unrealized gains and losses are reported as a separate component of stockholders’ equity within accumulated other comprehensive income (loss). We have determined that the gross unrealized losses on available for sale securities at September 29, 2017 and September 30, 2016 are temporary in nature. We review our investments to identify and evaluate investments that have indications of possible impairment. The techniques used to measure the fair value of our investments are described in Note 5 - Fair Value . Factors considered in determining whether a loss is temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and our intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. Substantially all of our fixed income securities are rated investment grade or better. We received proceeds from sales of available-for-sale securities of $44.6 million during the fiscal year ended September 29, 2017 . During the fiscal year ended September 30, 2016 we received proceeds from sales of available-for-sale securities of $51.6 million . Such sales resulted in the recording of gross realized gains of zero and $0.1 million and gross realized losses of $0.1 million and $0.2 million during the fiscal years ended September 29, 2017 and September 30, 2016 , respectively, which have been recorded within other (expense) income.

Fair Value

Fair Value	12 Months Ended
	Sep. 29, 2017
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE We group our financial assets and liabilities measured at fair value on a recurring basis in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets with insufficient volume or infrequent transactions (less active markets) or model-driven valuations in which all significant inputs are observable or can be derived principally from, or corroborated with, observable market data. Level 3 - Fair value is derived from valuation techniques in which one or more significant inputs are unobservable, including assumptions and judgments made by us. Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis We measure certain assets and liabilities at fair value on a recurring basis such as our financial instruments and derivatives. There have been no transfers between Level 1, 2 or 3 assets or liabilities during the fiscal year ended September 29, 2017 . Assets and liabilities measured at fair value on a recurring basis consist of the following (in thousands): September 29, 2017 Fair Value Active Markets for Identical Assets (Level 1) Observable Inputs (Level 2) Unobservable Inputs (Level 3) Assets Money market funds $ 36 $ 36 $ — $ — Commercial paper 57,911 — 57,911 — Corporate bonds 26,210 — 26,210 — Total assets measured at fair value $ 84,157 $ 36 $ 84,121 $ — Liabilities Contingent consideration $ 1,679 $ — $ — $ 1,679 Common stock warrant liability 40,775 — — 40,775 Total liabilities measured at fair value $ 42,454 $ — $ — $ 42,454 September 30, 2016 Fair Value Active Markets for Identical Assets (Level 1) Observable Inputs (Level 2) Unobservable Inputs (Level 3) Assets Money market funds $ 1,172 $ 1,172 $ — $ — Commercial paper 102,928 — 102,928 — US treasuries and agency bonds 6,002 — 6,002 — Corporate bonds 14,799 — 14,799 — Total assets measured at fair value $ 124,901 $ 1,172 $ 123,729 $ — Liabilities Contingent consideration $ 848 $ — $ — $ 848 Warrant liability 38,253 — — 38,253 Total liabilities measured at fair value $ 39,101 $ — $ — $ 39,101 The quantitative information utilized in the fair value calculation of our Level 3 liabilities are as follows: Liabilities Valuation Technique Unobservable Input September 29, 2017 September 30, 2016 Contingent consideration Discounted cash flow Discount rate 9.2% 12.9% Probability of achievement 70% - 100% 75% - 100% Timing of cash flows 2 - 8 months 1 year Warrant liability Black-scholes model Volatility 44.9% 43.2% Discount rate 1.62% 1.14% Expected life 3.2 years 4.2 years Exercise price $14.05 $14.05 Stock price $44.61 $42.34 Dividend rate —% —% The fair values of the contingent consideration liabilities were estimated based upon a risk-adjusted present value of the probability-weighted expected payments by us. Specifically, we considered base, upside and downside scenarios for the operating metrics upon which the contingent payments are to be based. Probabilities were assigned to each scenario and the probability-weighted payments were discounted to present value using risk-adjusted discount rates. The changes in assets and liabilities with inputs classified within Level 3 of the fair value hierarchy consist of the following (in thousands): Fiscal Year 2017 September 30, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 29, Contingent consideration $ 848 $ 180 $ 1,701 $ (1,050 ) $ — $ 1,679 Warrant liability $ 38,253 $ 2,522 $ — $ — $ — $ 40,775 Fiscal Year 2016 October 2, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 30, Contingent consideration $ 1,150 $ 98 $ — $ (400 ) $ — $ 848 Warrant liability $ 21,822 $ 16,431 $ — $ — $ — $ 38,253 Fiscal Year 2015 October 3, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 October 2, Trading securities $ 250 $ — $ 500 $ (750 ) $ — $ — Contingent consideration $ 820 $ 330 $ — $ — $ — $ 1,150 Warrant liability $ 15,802 $ 6,020 $ — $ — $ — $ 21,822

Accounts Receivables Allowances

Accounts Receivables Allowances	12 Months Ended
	Sep. 29, 2017
Receivables [Abstract]
Accounts Receivables Allowances	ACCOUNTS RECEIVABLES ALLOWANCES Summarized below is the activity in our accounts receivable allowances including customer returns, doubtful accounts and other items as follows (in thousands): Fiscal Year 2017 2016 2015 Balance - beginning of year $ 3,279 $ 5,745 $ 725 Provision, net 29,512 10,453 11,010 Charge-offs (23,381 ) (12,919 ) (5,990 ) Balance - end of year $ 9,410 $ 3,279 $ 5,745 The balances at the end of fiscal years 2017 , 2016 and 2015 primarily include compensation credits and customer returns allowances of $8.9 million , $3.0 million and $5.5 million , respectively, and allowances for doubtful accounts of $0.3 million for fiscal year 2017 and $0.2 million for fiscal years 2016 and 2015 .

Inventories

Inventories	12 Months Ended
	Sep. 29, 2017
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following (in thousands): September 29, 2017 September 30, 2016 Raw materials $ 78,999 $ 67,378 Work-in-process 13,962 9,157 Finished goods 43,113 38,400 Total $ 136,074 $ 114,935

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Sep. 29, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consist of the following (in thousands): September 29, September 30, Land, buildings and improvements $ — $ 12,572 Construction in process 22,195 9,415 Machinery and equipment 160,955 126,432 Leasehold improvements 13,809 12,152 Furniture and fixtures 2,078 1,469 Capital lease assets 20,410 3,207 Computer equipment and software 16,539 12,954 Total property and equipment 235,986 178,201 Less accumulated depreciation and amortization (104,967 ) (79,034 ) Property and equipment — net $ 131,019 $ 99,167 In fiscal year 2017 capital lease assets includes $16.9 million of assets related to our corporate facility lease obligation, with the remaining balance primarily related to leased equipment. In fiscal year 2016 the capital lease assets are primarily related to leased equipment. Depreciation and amortization expense related to property and equipment for fiscal years 2017 , 2016 and 2015 was $ 27.3 million , $20.4 million and $15.7 million , respectively.

Debt

Debt	12 Months Ended
	Sep. 29, 2017
Debt Disclosure [Abstract]
Debt	DEBT As of September 29, 2017 , we had $686.7 million of outstanding Term Loan borrowings under the Credit Agreement and $160.0 million of borrowing capacity under our Revolving Facility. The history of our Term Loans, Credit Agreement and Revolving Facility are further discussed below. On May 8, 2014, we entered into a credit agreement (Credit Agreement) with a syndicate of lenders that provided for term loans in an aggregate principal amount of $350.0 million , which were scheduled to mature in May 2021 (Initial Term Loans) and a revolving credit facility of $100.0 million initially (as increased by the amendments described below, Revolving Facility). In February 2015, we executed an amendment to the Credit Agreement that increased our aggregate borrowing capacity under the Revolving Facility to $130 million . The Initial Term Loans were issued with an original issue discount of 0.75% , which is being amortized over the term of the Initial Term Loans using the straight-line method, which approximates the effective interest rate method. On August 31, 2016, we entered into an amendment (2016 Incremental Term Loan Amendment) to our Credit Agreement which provided for incremental term loans in an aggregate principal amount of $250.0 million , which were scheduled to mature in May 2021 (2016 Incremental Term Loans). The terms of the 2016 Incremental Term Loans were identical to the terms of the Initial Term Loans, other than with respect to upfront fees, original issue discount and arrangement, structuring or similar fees payable in connection therewith. The 2016 Incremental Term Loans were issued with an original issue discount of 0.95% , which is being amortized over the term of the 2016 Incremental Term Loans using the straight-line method, which approximates the effective interest rate method. On March 10, 2017, we entered into multiple amendments to our Credit Agreement (the March 2017 Amendments), which consisted of (i) the Second Incremental Amendment, by and among MACOM, Barclays Bank PLC and Goldman Sachs Bank USA, as administrative agent, (ii) the Refinancing Amendment, by and among MACOM, the lenders party thereto and Goldman Sachs Bank USA, as administrative agent and (iii) Amendment No. 4 to the Credit Agreement, by and among MACOM, the revolving credit lenders and Goldman Sachs Bank USA, as administrative agent. Pursuant to the March 2017 Amendments, we increased the revolving credit commitments available under our revolving credit facility by $30.0 million to $160.0 million . No amounts were drawn under the Revolving Facility on the closing date of the March 2017 Amendments or as of September 29, 2017 . In addition, pursuant to the March 2017 Amendments, our existing term loans were refinanced at a reduced interest rate. Further, pursuant to the March 2017 Amendments, the Credit Agreement was amended to provide that the financial covenant under the Revolving Facility would only be tested if, as of the last date of any fiscal quarter, the aggregate amount outstanding under the Revolving Facility (other than with respect to (a) undrawn letters of credit in an amount not to exceed $5.0 million and (b) letters of credit that have been cash collateralized pursuant to the Credit Agreement) exceeds 35% of the revolving credit commitments under the Revolving Facility. Prior to the March 2017 Amendments, the threshold for testing the financial covenant was set at 25% of the revolving credit commitments under the Revolving Facility. On May 19, 2017, we entered into two amendments to our Credit Agreement (the May 2017 Amendments) which consisted of (i) the Second Refinancing Amendment, among MACOM, Morgan Stanley Senior Funding, Inc. and the other term lenders party thereto and Goldman Sachs Bank USA, as administrative agent (the Second Refinancing Amendment), and (ii) the Second Incremental Term Loan Amendment, among MACOM, Morgan Stanley Senior Funding, Inc. and the other lenders party thereto and Goldman Sachs Bank USA, as administrative agent (the Second Incremental Term Loan Amendment). Pursuant to the Second Refinancing Amendment, our then existing term loans of $588.5 million were refinanced with a new tranche of term loans. The refinanced term loans will mature in May 2024 and bear interest at: (i) for LIBOR loans for any interest period, a rate per annum equal to the LIBOR rate as determined by the administrative agent, plus an applicable margin of 2.25% ; and (ii) for base rate loans, a rate per annum equal to the greater of (a) the prime rate quoted in the print edition of the Wall Street Journal, Money Rates Section, (b) the federal funds rate plus one-half of 1.00% and (c) the LIBOR rate applicable to a one-month interest period plus 1.00% (but, in each case, not less than 1.00% ), plus an applicable margin of 1.25% . The effective interest rate on our term loans was 3.5% as of September 29, 2017 . Pursuant to the Second Incremental Term Loan Amendment, we borrowed an additional $100.0 million of incremental term loans (the 2017 Incremental Term Loans, together with the Initial Term Loans and the 2016 Incremental Term Loans, Term Loans) on the same terms as the new tranche of term loans incurred pursuant to the Second Refinancing Amendment. The 2017 Incremental Term Loans and the new tranche of term B loans were issued with an original issue discount of 0.50% , which is being amortized over the term of the existing Term Loans using the straight-line method, which approximates the effective interest rate method. We incurred $8.7 million in fees for the issuance of the Credit Agreement in May 2014, and $3.2 million in fees for the issuance of the 2016 Incremental Term Loan Amendment in August 2016, which were initially recorded as deferred financing costs and are being amortized over the life of the related Term Loans as interest expense. In March 2017, we incurred an additional $1.0 million in fees for the issuance of the March 2017 Amendments, and in May 2017, we incurred an additional $11.1 million in fees for the issuance of the May 2017 Amendments. In connection with the March 2017 Amendments and the May 2017 Amendments, we determined that $0.9 million and $1.1 million of deferred costs previously capitalized should be expensed during our second and third fiscal quarters, respectively, as a loss on extinguishment of debt related to syndicated lenders whose debt was extinguished. As of September 29, 2017 , approximately $13.7 million of deferred financing costs remain unamortized, of which $12.5 million related to the 2017 Incremental Term Loans is recorded as a direct reduction of the recognized debt liabilities in our accompanying consolidated balance sheet, and $1.2 million related to the Revolving Facility is recorded in other assets in our accompanying consolidated balance sheet. The Term Loans are secured by a first priority lien on substantially all of our assets and provide that we must comply with certain financial and non-financial covenants. The combined Term Loans are payable in quarterly principal installments of approximately $1.7 million on the last business day of each calendar quarter, with the remainder due on the maturity date. In the event that we divest a business, the net cash proceeds of the divestment are generally required, subject to certain exceptions, to be applied to repayment of outstanding Term Loans except to the extent we reinvest such proceeds in assets useful for our business within 18 months of receiving the proceeds. If we enter into a binding agreement to reinvest such proceeds within 18 months of receiving them, we have until the later of 18 months following our receipt of the proceeds and 6 months following the date of such agreement to complete the reinvestment. As of September 29, 2017 , the following remained outstanding on the Term Loans: Principal balance $ 686,741 Unamortized discount (5,835 ) Total term loans 680,906 Current portion 6,885 Long-term, less current portion $ 674,021 As of September 29, 2017 , the minimum principal payments under the Term Loans in future fiscal years were as follows (in thousands): 2018 $ 6,885 2019 6,885 2020 6,885 2021 6,885 2022 6,885 Thereafter 652,316 Total $ 686,741 The fair value of the Term Loans was estimated to be approximately $696.2 million as of September 29, 2017 and was determined using Level 2 inputs, including a quoted rate from a bank.

Capital Lease and Financing Obl

Capital Lease and Financing Obligations (Notes)	12 Months Ended
	Sep. 29, 2017
Capital Lease and Financing Obligations [Abstract]
Capital Leases in Financial Statements of Lessee Disclosure	10. CAPITAL LEASE AND FINANCING OBLIGATIONS Corporate Facility Financing Obligation On May 26, 2016, we entered into a Purchase and Sale Agreement (Purchase Agreement) with Calare Properties, Inc., a Delaware corporation (together with its affiliates, the Buyer), for the sale and subsequent leaseback of our corporate headquarters, located at 100 Chelmsford Street, Lowell, Massachusetts. The transactions contemplated by the Purchase Agreement closed on December 28, 2016, at which time we also entered into three lease agreements with the Buyer including: (1) a 20 -year leaseback of the facility located at 100 Chelmsford Street (the 100 Chelmsford Lease), (2) a 20 -year build-to-suit lease arrangement for the construction and subsequent lease back of a new facility to be located at 144 Chelmsford Street (the 144 Chelmsford Lease), and (3) a 14 -year building lease renewal of an adjacent facility at 121 Hale Street (the 121 Hale Lease, and together with the 100 Chelmsford Lease and the 144 Chelmsford Lease, the Leases). Because the transactions contemplated by the Purchase Agreement and the related Leases were negotiated and consummated at the same time and in contemplation of one another to achieve the same commercial objective, the transactions are accounted for by us as a single unit of accounting. In addition, the Leases were determined to represent a failed sale-leaseback due to our continuing involvement in the properties in the form of non-recourse financing. As a result, the Leases are accounted for under the financing method and we will be the deemed accounting owner under the arrangement, including the assets to be constructed under the 144 Chelmsford Lease. We will continue to recognize the existing building and improvements sold under the Purchase Agreement, capitalize the 121 Hale Street building as well as the assets constructed under the Leases, and depreciate the assets over the shorter of their estimated useful lives or the lease terms. The sale proceeds from the Purchase Agreement of $8.2 million (which includes $4.2 million in cash and $4.0 million in construction allowances) and the fair value of the 121 Hale Street building of $4.0 million were recognized as a financing obligation on our balance sheet and are being amortized over the 20 -year lease term based on the minimum lease payments required under the Leases and our incremental borrowing rate. Future construction costs funded by the Buyer under the 144 Chelmsford Lease will be recognized as additional financing obligations on our balance sheet as incurred, and will be amortized over the 20 -year lease term based on the minimum lease payments required under the Leases and our incremental borrowing rate. As of September 29, 2017 , we have recorded $3.6 million of construction costs as additional financing obligations within long-term debt in our accompanying consolidated financial statements. As a result of the failed sale-leaseback accounting, we calculated a financing obligation as of the December 28, 2016 inception of the lease based on the future minimum lease payments discounted at 8.5% . The discount rate represents the estimated incremental borrowing rate over the lease term of 20 years. The minimum lease payments are recorded as interest expense and in part as a payment of principal reducing the financing obligation. The real property assets in the transaction remain on the consolidated balance sheets and continue to be depreciated over their remaining useful lives. As of September 29, 2017 , approximately $15.8 million of the financing obligation was outstanding associated with the Leases, of which $3.6 million was associated with the 144 Chelmsford Lease that has not yet been placed in service. Acquired Capital Leases In connection with the FiBest Acquisition in December 2015 and the BinOptics Acquisition in December 2014 we assumed certain capital lease obligations, of which approximately $2.3 million was outstanding as of September 29, 2017 . Future Minimum Payments Under Capital lease Obligations As of September 29, 2017 , future minimum payments under capital lease obligations and financing obligations related to the Leases were as follows (in thousands): Fiscal year ending: Amount 2018 $ 1,895 2019 1,791 2020 1,619 2021 1,485 2022 1,276 Thereafter 19,264 Total minimum capital lease payments $ 27,330 Less amount representing interest $ (14,698 ) Present value of net minimum capital lease payments $ 12,632

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 29, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Operating Leases —We have non-cancelable operating lease agreements for office, research and development and manufacturing space in the United States and foreign locations. We also have operating leases for certain equipment, automobiles and services in the United States and foreign jurisdictions. These lease agreements expire at various dates through 2026, and certain agreements contain provisions for extension at substantially the same terms as currently in effect. Lease escalation clauses, rent abatements and/or concessions, such as rent holidays and landlord or tenant incentives or allowances, are typically included in the determination of straight-line rent expense over the lease term. Future minimum lease payments for the next five fiscal years as of September 29, 2017 , are as follows (in thousands): 2018 $ 11,116 2019 9,001 2020 5,985 2021 3,828 2022 3,113 Thereafter 7,999 Total minimum lease payments $ 41,042 Rent expense incurred under non-cancelable operating leases was $10.9 million , $7.0 million and $6.5 million in fiscal years 2017 , 2016 and 2015 , respectively. Asset Retirement Obligations —We are obligated under certain facility leases to restore those facilities to the condition in which we or our predecessors first occupied the facilities. We are required to remove leasehold improvements and equipment installed in these facilities prior to termination of the leases. As of the end of fiscal years 2017 , 2016 and 2015 , the estimated costs for the removal of these assets are recorded as asset retirement obligations was $2.3 million , $4.3 million and $1.3 million , respectively. Unused Letter of Credit —As of September 29, 2017 , we had outstanding unused letters of credit from a bank aggregating $0.4 million . Purchase Commitments —As of September 29, 2017 , we had outstanding non-cancelable purchase commitments aggregating to $ 1.8 million pursuant to inventory supply arrangements. Litigation —From time to time we may be subject to commercial disputes, employment issues, claims by other companies in the industry that we have infringed their intellectual property rights and other similar claims and litigations. Any such claims may lead to future litigation and material damages and defense costs. Other than as set forth below, we were not involved in any material pending legal proceedings during the year ended September 29, 2017 . GaN Lawsuit Against Infineon — On April 26, 2016, we and our wholly-owned subsidiary Nitronex, LLC brought suit against Infineon Technologies Americas Corporation (Infineon Americas) and Infineon Technologies AG (Infineon AG and collectively, with Infineon Americas, Infineon) in the Federal District Court for the Central District of California, seeking injunctive relief, monetary damages, and specific performance of certain contractual obligations. On July 19, 2016, we filed a first amended complaint, and, on November 21, 2016, we filed a second amended complaint. After motions to dismiss certain claims from MACOM’s second amended complaint were denied on February 28, 2017, Infineon AG answered on March 24, 2017, asserting no counterclaims. Infineon Americas also answered and counterclaimed on March 24, 2017 and then submitted amended counterclaims on April 14, 2017. The court dismissed one of the counterclaims on June 5, 2017, and Infineon filed further amended counterclaims on June 19, 2017. MACOM answered the counterclaims on August 16, 2017. The suit arises out of agreements relating to GaN patents that were executed in 2010 by Nitronex Corporation (acquired by us in 2014) and International Rectifier Corporation (International Rectifier) (acquired by Infineon AG in 2015). We assert claims for breach of contract, breach of the covenant of good faith and fair dealing, declaratory judgment of contractual rights, declaratory judgment of non-infringement of patents, and, against Infineon AG only, intentional interference with contract. If successful, the relief sought in our second amended complaint would, among other remedies, require Infineon to assign back to us certain GaN-related Nitronex patents that were previously assigned to International Rectifier and enjoin Infineon from proceeding with its marketing and sales of certain types of GaN-on-Si products. In an order dated October 31, 2016, the Court granted us a preliminary injunction against Infineon, which then issued on December 7, 2016 and was modified on March 6, 2017. The preliminary injunction declares that an exclusive licensing arrangement between us and Infineon that Infineon had purported to terminate is still in effect and prohibits Infineon Americas and others acting in concert with it from engaging in certain activities in our exclusive field, which includes RF power amplifiers for cellular base stations. Infineon appealed the preliminary injunction order to the Federal Circuit on January 3, 2017, and MACOM appealed the modification order on April 5, 2017. The appeals are fully briefed and were argued together on September 6, 2017, with a decision expected in the next few months. Meanwhile, the district court case is proceeding, with trial set to begin on February 26, 2019. With respect to the above legal proceeding, we have not been able to reasonably estimate the amount or range of any possible loss, and accordingly have not accrued or disclosed any related amounts of possible loss in the accompanying consolidated financial statements.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Sep. 29, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS We established a defined contribution savings plan under Section 401(k) of the Internal Revenue Code of 1986, as amended (Section 401(k)) on October 1, 2009 ( 401 (k) Plan). The 401 (k) Plan follows a calendar year, covers substantially all U.S. employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis, subject to legal limitations. Our contributions to the plan may be made at the discretion of the board of directors. During the fiscal year ended September 29, 2017 , we contributed $2.4 million to our 401 (k) Plan for calendar year 2016 . There were no contributions made by us to the 401 (k) Plan for calendar year 2017 through September 29, 2017 . Our employees located in foreign jurisdictions meeting minimum age and service requirements participate in defined contribution plans whereby participants may defer a portion of their annual compensation on a pretax basis, subject to legal limitations. Company contributions to these plans are discretionary and vary per region. We expensed contributions of $1.3 million , $1.1 million and $1.0 million for fiscal years 2017 , 2016 and 2015 , respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Sep. 29, 2017
Other Liabilities Disclosure [Abstract]
Accrued Liabilities	ACCRUED LIABILITIES Accrued liabilities consist of the following (in thousands): September 29, September 30, Compensation and benefits $ 32,505 $ 32,563 Distribution costs 5,777 3,584 Income taxes payable 4,184 — Product warranty 3,672 1,039 Professional fees 2,140 1,706 Deferred revenue 1,994 340 Contingent consideration 1,679 848 Rent and utilities 1,257 1,310 Purchase price holdback 1,000 — Asset retirement obligations 959 2,932 Restructuring costs 627 3,104 Interest payable 532 4,314 Other 3,911 2,628 Total $ 60,237 $ 54,368

Restructurings

Restructurings	12 Months Ended
	Sep. 29, 2017
Restructuring and Related Activities [Abstract]
Restructurings	RESTRUCTURINGS We have periodically implemented restructuring actions in connection with broader plans to reduce staffing, reduce our internal manufacturing footprint and, generally, reduce operating costs. The restructuring expenses are primarily comprised of direct and incremental costs related to headcount reductions including severance and outplacement fees for the terminated employees, as well as facility closure costs. The following is a summary of the costs incurred and remaining balances included in accrued expenses related to restructuring actions taken (in thousands): Total Balance - October 3, 2014 $ 801 Current period charges 1,280 Payments (1,138 ) Balance - October 2, 2015 943 Current period charges 3,465 Payments (1,304 ) Balance - September 30, 2016 3,104 Current period charges 2,744 Payments (5,221 ) Balance at September 29, 2017 $ 627 The restructuring expenses recorded to date are expected to be paid through the remainder of calendar year 2017 . We expect to incur additional restructuring costs in the range of approximately $3.6 million and $4.5 million during our fiscal year 2018 as we complete restructuring actions primarily associated with facility consolidations.

Product Warranties

Product Warranties	12 Months Ended
	Sep. 29, 2017
Guarantees [Abstract]
Product Warranties	PRODUCT WARRANTIES We establish a product warranty liability at the time of revenue recognition. Product warranties generally have terms of 12 months and cover nonconformance with specifications and defects in material or workmanship. For sales to distributors, our warranty generally begins when the product is resold by the distributor. The liability is based on estimated costs to fulfill customer product warranty obligations and utilizes historical product failure rates. Should actual warranty obligations differ from estimates, revisions to the warranty liability may be required. Product warranty liability activity is as follows (in thousands): Fiscal Years 2017 2016 2015 Balance — beginning of year $ 1,039 $ 656 $ 446 Acquired 952 413 50 Provisions 1,737 (30 ) 160 Direct charges (56 ) — — Balance — end of year $ 3,672 $ 1,039 $ 656

Intangible Assets

Intangible Assets	12 Months Ended
	Sep. 29, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS Amortization expense related to intangible assets is as follows (in thousands): Fiscal Years 2017 2016 2015 Cost of revenue $ 30,286 $ 26,615 $ 27,285 Selling, general and administrative 35,456 23,640 11,695 Total $ 65,742 $ 50,255 $ 38,980 Intangible assets consist of the following (in thousands): September 29, September 30, Acquired technology $ 251,655 $ 165,397 Customer relationships 556,648 207,674 In-process research and development — 8,000 Trade name 3,400 3,400 Total 811,703 384,471 Less accumulated amortization (190,611 ) (124,869 ) Intangible assets — net $ 621,092 $ 259,602 A summary of the activity in intangible assets and goodwill follows (in thousands): Intangible Assets Total Acquired Customer In-Process Research and Development Trade Name Goodwill Balance at October 2, 2015 $ 318,006 $ 162,536 $ 144,070 $ 8,000 $ 3,400 $ 93,346 Acquired 65,350 10,400 54,950 — — 20,412 Fair value adjustment 1,678 78 1,600 — — 3,475 Currency translation adjustments 8,857 1,803 7,054 — — 2,791 Impairments of intangible assets (10,088 ) (10,088 ) — — — — Other intangibles purchased 668 668 — — — — Balance at September 30, 2016 384,471 165,397 207,674 8,000 3,400 120,024 Acquired 436,181 83,518 352,663 — — 195,145 Placed in service — 3,648 — (3,648 ) — — Fair value adjustment — — — — — 220 Currency translation adjustments (4,597 ) (908 ) (3,689 ) — — (1,624 ) Impairments of intangible assets (4,352 ) — — (4,352 ) — — Balance at September 29, 2017 $ 811,703 $ 251,655 $ 556,648 $ — $ 3,400 $ 313,765 As of September 29, 2017 , our estimated amortization of our intangible assets in future fiscal years, subject to the completion of the purchase price allocation for the AppliedMicro, Picometrix, Antario and TPC acquisitions, was as follows (in thousands): 2018 2019 2020 2021 2022 Thereafter Amortization expense $ 82,798 90,429 88,030 79,161 65,468 211,806 Our trade name is an indefinite-lived intangible asset. During development, in-process research and development (IPR&D) is not subject to amortization and is tested for impairment annually or more frequently if events or changes in circumstances indicate that the asset might be impaired. The impairment test consists of both a qualitative and quantitative assessment using an assumption of ‘more likely than not’ to determine if there were any impairment indicators. If impairment exists, a loss is recognized in an amount equal to that excess. Once an IPR&D project is complete, it becomes a definite long-lived intangible asset and is evaluated for impairment in accordance with our policy for long-lived assets. During the fourth quarter of fiscal year 2017, we completed the last IPR&D project and placed the acquired technology into service. Prior to placing the technology into service we performed an impairment assessment, at which time we determined that the value of the technology was impaired by $4.4 million , which was expensed in our fiscal fourth quarter of 2017. The remaining $3.6 million was placed in service as acquired technology. Accumulated amortization for the acquired technology and customer relationships was $106.8 million and $83.9 million , respectively, as of September 29, 2017 , and $ 76.7 million and $ 48.1 million, respectively, as of September 30, 2016 . During the second quarter of fiscal year 2016, we made a strategic decision to exit the product line and end programs associated with our GaN-on-SiC license and technology transfer to focus on development of our GaN-on-Si efforts. As a result of this strategic decision, we determined that the intangible assets and contractual commitments under the long-term technology licensing and transfer agreement signed in July 2013, as well as certain dedicated fixed assets and inventory, would no longer have any future benefit. The associated charges incurred during the nine months ended July 1, 2016 were $ 13.8 million , which included a write-off of $ 10.1 million of intangible assets, $ 0.6 million of property and equipment, $ 1.1 million of contractual commitments and $ 2.0 million of inventory.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 29, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Deferred income taxes reflect the net effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and amounts used for income tax purposes. The components of our deferred tax assets and liabilities are as follows (in thousands): September 29, September 30, Deferred tax assets (liabilities): Federal and foreign net operating losses and credits $ 396,871 $ 85,256 Intangible assets (180,544 ) (49,725 ) Property and equipment (1,045 ) (2,730 ) Other non-current deferred tax assets 20,756 21,855 Discontinued operations — 9,100 Deferred compensation 9,291 5,545 Deferred gain 14,853 19,011 Valuation allowance (274,406 ) (10,471 ) Total deferred tax (liability) asset $ (14,224 ) $ 77,841 Included in the above table are the attributes of our Japan jurisdiction which is in a net liability position of $ 8.8 million relating primarily to intangible assets. In fiscal year 2016 we adopted ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes. Upon adoption we included our current deferred income tax assets with our noncurrent deferred income tax assets; no adjustments were made to deferred tax liabilities. As of September 29, 2017 , we had $1,084.8 million of gross federal net operating loss (NOL) carryforwards consisting of $772.7 million relating to the AppliedMicro Acquisition, $158.9 million relating to the Mindspeed Acquisition, $26.2 million relating to the BinOptics Acquisition and $127.0 million relating to losses generated by MACOM. The federal NOL carryforwards will expire at various dates through 2036. The reported net operating loss carryforward includes any limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, which applies to an ownership change as defined under Section 382. During the fourth quarter of fiscal year 2016, we identified and corrected a prior period error where we understated our income tax benefit during 2013 through 2015. This was a result of the incorrect recording of intercompany pretax income among a few of our operating entities and due to the fact that these entities had different statutory tax rates. The out-of-period correction resulted in a $ 3.9 million increase in income tax benefit in the fiscal year ended September 30, 2016 of which $ 1.7 million , $ 1.0 million and $ 1.2 million related to the prior fiscal years 2015, 2014 and 2013, respectively. The domestic and foreign income (loss) from continuing operations before taxes were as follows (in thousands): Fiscal Years 2017 2016 2015 United States $ (111,432 ) $ (46,593 ) $ (34,251 ) Foreign 61,927 25,022 18,851 (Loss) income from operations before income taxes $ (49,505 ) $ (21,571 ) $ (15,400 ) The components of the provision (benefit) for income taxes are as follows (in thousands): Fiscal Years 2017 2016 2015 Current: Federal $ 100 $ (5,861 ) $ (19,015 ) State 225 (766 ) 688 Foreign 7,307 906 1,092 Current provision (benefit) 7,632 (5,721 ) (17,235 ) Deferred: Federal (42,637 ) (8,163 ) 10,845 State (4,037 ) (502 ) (4,131 ) Foreign (466 ) (2,603 ) (1,302 ) Change in valuation allowance 140,419 (994 ) 1,965 Deferred provision (benefit) 93,279 (12,262 ) 7,377 Total provision (benefit) $ 100,911 $ (17,983 ) $ (9,858 ) We recognize deferred tax assets to the extent that we believe that these assets are more likely than not to be realized. In making this determination, we consider available positive and negative evidence and factors that may impact the valuation of our deferred tax asset including results of recent operations, future reversals of existing taxable temporary differences, projected future taxable income, and tax-planning strategies. A significant piece of objective negative evidence evaluated was the cumulative U.S. loss incurred over the three-year period ended September 29, 2017 which we believe limited our ability to consider other subjective evidence, such as our projections for future growth. Certain transaction and integration related expenses incurred in the U.S., associated primarily with the AppliedMicro Acquisition during the three months ended March 31, 2017, resulted for the first time in significant negative objective evidence in the form of adjusted cumulative losses in the U.S. over the past three-year period. This resulted in our determination that there was not sufficient objectively verifiable positive evidence to offset this negative objective evidence and we concluded that a full valuation allowance totaling $93.5 million was required for our U.S. deferred tax assets as of September 29, 2017. In addition, a full valuation allowance was established against the U.S. deferred tax assets acquired in connection with the AppliedMicro Acquisition. The $274.4 million of valuation allowance as of September 29, 2017 relates primarily to federal and state NOLs and tax credit carryforwards assumed in the AppliedMicro Acquisition along with an establishment of a full valuation allowance against our U.S. deferred tax assets, and UK tax credit and NOL carryforwards whose recovery is not considered more likely than not. The $10.5 million of valuation allowance as of September 30, 2016 related primarily to state NOL and tax credit carryforwards assumed in the Mindspeed Acquisition and UK tax credit and NOL carryforwards whose recovery is not considered more likely than not. The change during the year ending September 29, 2017 of $263.9 million primarily relates to state NOL and tax credit carryforwards assumed in the AppliedMicro Acquisition along with an establishment of a full valuation allowance against our U.S. deferred tax assets. Our effective tax rates differ from the federal and statutory rate as follows: Fiscal Years 2017 2016 2015 Federal statutory rate 35.0% 35.0% 35.0% Foreign rate differential 31.9 40.1 30.5 State taxes net of federal benefit 0.2 1.0 3.5 Warrant liabilities (1.8) (26.7) (13.7) Change in valuation allowance (270.0) 3.0 (6.0) Research and development credits 12.8 16.9 16.1 Correction of prior period — 18.3 — Provision to return adjustments (4.0) 3.5 9.9 Nondeductible compensation expense (4.1) (9.2) (8.9) Nondeductible legal fees (3.9) (1.8) (4.1) Other permanent differences 0.1 3.3 1.6 Effective income tax rate (203.8)% 83.4% 63.9% For fiscal years 2017 , 2016 and 2015 , the effective tax rates to calculate the tax benefit on $49.5 million , $21.6 million and $15.4 million , respectively, of pre-tax loss from continuing operations were (203.8)% , 83.4% and 63.9% , respectively. The effective income tax rate for fiscal years 2017 , 2016 and 2015 were primarily impacted by a lower income tax rate in many foreign jurisdictions in which our foreign subsidiaries operate, research and development tax credits, and the fair market value adjustment of warrant liabilities. For fiscal year 2017, the effective tax rate was also impacted by an establishment of a full valuation allowance against our U.S. deferred tax assets. For fiscal years 2015 and 2016, the rate was impacted by a retroactive enactment of the R&D tax credit from fiscal years 2014 and 2015, respectively, and a larger shift of the revenue associated with foreign entities taxed at lower rates as part of our auto divestiture. All earnings of foreign subsidiaries are considered indefinitely reinvested for the periods presented. Undistributed earnings of all foreign subsidiaries as of September 29, 2017 aggregated $158.6 million , with Ireland and Grand Cayman accounting for $58.3 million and $90.1 million , respectively. It is not practicable to determine the U.S. federal and state deferred tax liabilities associated with such foreign earnings. Activity related to unrecognized tax benefits is as follows (in thousands): Amount Balance - October 2, 2015 (1,670 ) Additions based on tax positions — Reductions based on tax positions — Balance - September 30, 2016 $ (1,670 ) Additions based on tax positions — Reductions based on tax positions — Balance at September 29, 2017 $ (1,670 ) The balance of the unrecognized tax benefit as of September 29, 2017 , is included in other long-term liabilities in the accompanying consolidated balance sheets. Due to the establishment of a full valuation allowance against our U.S. deferred tax assets, only $0.3 million of the entire balance of unrecognized tax benefits, if recognized, will reduce income tax expense. It is our policy to recognize any interest and penalties accrued related to unrecognized tax benefits in income tax expense. During fiscal year 2017 , we did not make any payment of interest and penalties. There was nothing accrued in the consolidated balance sheets for the payment of interest and penalties at September 29, 2017 , as the remaining unrecognized tax benefits would only serve to reduce our current federal and state NOL carryforwards, if ultimately recognized. A summary of the fiscal tax years that remain subject to examination, as of September 29, 2017 , for the Company’s significant tax jurisdictions are: Jurisdiction Tax Years Subject to Examination United States—federal 2013 - forward United States—various states 2013 - forward Ireland 2012 - forward Generally, we are no longer subject to federal income tax examinations for years before 2013, except to the extent of loss and tax credit carryforwards from those years.

Share - Based Compensation Plan

Share - Based Compensation Plans	12 Months Ended
	Sep. 29, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share - Based Compensation Plans	SHARE-BASED COMPENSATION PLANS Stock Plans We have three equity incentive plans: the Amended and Restated 2009 Stock Incentive Plan (2009 Plan), the 2012 Omnibus Incentive Plan, as amended (2012 Plan) and the 2012 Employee Stock Purchase Plan, as amended and restated (ESPP). Upon the closing of our initial public offering, all shares that were reserved under the 2009 Plan but not awarded were assumed by the 2012 Plan. No additional awards will be made under the 2009 Plan. Under the 2012 Plan, we have the ability to issue incentive stock options (ISOs), nonqualified stock options (NQs), stock appreciation rights, restricted stock (RSAs), restricted stock units (RSUs), performance-based stock units (PRSUs) and other equity-based awards to employees, directors and outside consultants. The ISOs and NQs must be granted at a price per share not less than the fair value of our common stock on the date of grant. Options granted to date primarily vest based on certain market-based and performance-based criteria as described below. Certain of the share-based awards granted and outstanding as of September 29, 2017 , are subject to accelerated vesting upon a sale of the Company or similar changes in control. Options granted generally have a term of seven to ten years. As of September 29, 2017 , we had 13.0 million shares available for future issuance under the 2012 Plan. The financial impact of any modifications to share-based awards during the periods presented was not material. Outside of the three equity plans described above, we also grant incentive stock units (ISUs) liability awards to our international employees which typically vest over 4 years and for which the fair value is determined by our underlying stock price, which are settled in cash. As of September 29, 2017 , we had approximately 203,000 ISU awards outstanding with a liability value of $4.4 million recorded as accrued compensation. The related expense for these cash based incentive awards was $3.9 million , $4.0 million and $1.8 million in fiscal years 2017 , 2016 and 2015 , respectively. Share-Based Compensation The following table shows a summary of share-based compensation expense included in the Consolidated Statement of Operations during the periods presented (in thousands): Fiscal Years 2017 2016 2015 Cost of revenue $ 3,189 $ 2,150 $ 1,949 Research and development 10,565 6,568 5,447 Selling, general and administrative 22,581 18,236 12,039 Total $ 36,335 $ 26,954 $ 19,435 Amounts presented above include share-based compensation expense of $0.8 million for fiscal year 2017, which is recorded as discontinued operations related to employees of our Compute business and share-based compensation expense of $0.4 million for fiscal year 2015 related to employees terminated in conjunction with the Automotive divestiture in August 2015. As of September 29, 2017 , the total unrecognized compensation costs, adjusted for estimated forfeitures, related to outstanding stock options, restricted stock awards and units including awards with time-based and performance-based vesting was $62.1 million , which we expect to recognize over a weighted-average period of 2.5 years . Stock Options A summary of stock option activity for fiscal year 2017 is as follows (in thousands, except per share amounts): Number of Shares Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value Options outstanding - September 30, 2016 1,048 $ 23.18 Granted (1) 379 44.74 Exercised (234 ) 13.34 Forfeited, canceled or expired (16 ) 56.80 Options outstanding - September 29, 2017 1,177 $ 31.61 4.99 16,445 Options vested and expected to vest - September 29, 2017 1,177 $ 31.61 4.99 16,445 Options exercisable - September 29, 2017 397 $ 23.00 4.16 9,701 (1) Includes 59,107 shares that were converted in connection with the AppliedMicro Acquisition. Aggregate intrinsic value represents the difference between our closing stock price on September 29, 2017 , and the exercise price of outstanding, in-the-money options. The total intrinsic value of options exercised was $8.9 million , $3.7 million and $7.1 million for fiscal year 2017 , 2016 and 2015 , respectively. Stock Options with Performance-based Vesting Criteria We granted approximately 230,000 non-qualified stock options in 2016 and 2015 which will vest subject to certain performance metrics such as revenue and gross margin targets being achieved. The aggregate fair value of these stock options was approximately $2.4 million on the date of grant, and the options are subject to vesting based on performance and service conditions being met. We used a Black-Scholes option pricing model for estimating the fair value on the date of grant which ranged from $ 10.12 to $10.54 per option share. The fair value of stock options is affected by valuation assumptions, including volatility, the Company’s stock price, expected term of the option, risk-free interest rate and expected dividends. These stock options will fully vest and become exercisable if certain performance criteria are met or exceeded in any period of four consecutive fiscal quarters completed during the term of the options based on pre-established revenue and gross margin targets. The stock options have a term of seven years, assuming continued employment with or services to the Company, and have a weighted average exercise price of $ 34.22 and equal to the closing price of the Company’s common stock on the date of grant. As of September 29, 2017 , 50,000 shares of the performance-based stock options granted in fiscal year 2015 had vested as their performance metric had been met and all of the expense associated with these options had been fully recognized. The weighted average Black-Scholes input assumptions used for calculating the fair value of these performance-based stock options are as follows: Fiscal Years 2016 2015 Risk-free interest rate 1.15 % 1.2 % Expected term (years) 4 4 Expected volatility 31.8 % 36.2 % Expected dividends — % — % Stock Options with Market-based Vesting Criteria In January 2017, we granted 10,000 non-qualified stock options with a grant date fair value of $0.2 million that are subject to vesting only upon the market price of our underlying public stock closing above a certain price target within seven years of the date of grant. These non-qualified stock options with market related vesting conditions were valued using a Monte Carlo simulation model. Share-based compensation expense is recognized regardless of the number of awards that are earned based on the market condition and is recognized on a straight-line basis over the estimated service period of approximately three years. In the event that the Company’s underlying public stock achieves the target price of $80.70 per share based on a 30 day trailing average prior to the end of the estimated service period, any remaining unamortized compensation cost will be recognized. In November 2016, we granted 310,000 non-qualified stock options with a grant date fair value of $4.1 million that are subject to vesting only upon the market price of our underlying public stock closing above a certain price target within seven years of the date of grant. These non-qualified stock options with market related vesting conditions were valued using a Monte Carlo simulation model. Share-based compensation expense is recognized regardless of the number of awards that are earned based on the market condition and is recognized on a straight-line basis over the estimated service period of approximately three years. In the event that the Company’s underlying public stock achieves the target price of $66.96 per share based on a 30 day trailing average prior to the end of the estimated service period, any remaining unamortized compensation cost will be recognized During fiscal year 2016, we granted 300,000 non-qualified stock options with a grant date fair value of $ 3.5 million that are subject to vesting only upon the market price of our underlying public stock closing above a certain price target within seven years of the date of grant. These non-qualified stock options with market related vesting conditions were valued using a Monte Carlo simulation model. Share-based compensation expense is recognized regardless of the number of awards that are earned based on the market condition and is recognized on a straight-line basis over the estimated service period of approximately three years. In the event that the Company’s underlying public stock achieves the target price of $ 64.22 per share based on a 30 day trailing average prior to the end of the estimated service period, any remaining unamortized compensation cost will be recognized. During fiscal year 2015, we granted 30,000 stock options awards, with an exercise price of $ 29.80 , under the 2012 Plan with a grant date fair value of $ 0.4 million that are subject to vesting only upon the market price of the Company's underlying public stock closing at $ 63.60 for at least a consecutive three trading day period. These stock options' fair value of $ 12.38 per option was estimated using a Monte Carlo simulation model based on the market conditions vesting condition. Compensation cost is recognized on a straight-line basis over the estimated service period of approximately three years, expiring in September 2022. On July 26, 2017, our common stock closed above $63.60 per share for a consecutive three trading day period which resulted in the vesting of these market-based stock options and the corresponding expense was accelerated and fully recognized. The weighted average Monte Carlo input assumptions used for calculating the fair value of these market-based stock options are as follows: Fiscal Years 2017 2016 2015 Risk-free interest rate 1.9 % 2.1 % 1.9 % Expected term (years) 7 7 7 Expected volatility 32.3 % 36.5 % 37.4 % Restricted Stock Awards and Units A summary of restricted stock awards and units activity for fiscal year 2017 is as follows (in thousands): Number of Shares Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value Issued and unvested - September 30, 2016 1,708 $ 32.76 $ 72,165 Granted (1) 1,276 37.92 Vested (984 ) 26.63 Forfeited, canceled or expired (93 ) 36.30 Issued and unvested shares - September 29, 2017 1,907 39.20 $ 85,093 (1) Includes 306,089 shares that were converted in connection with the AppliedMicro Acquisition. As of September 29, 2017 , the aggregate intrinsic value of vesting restricted stock units including time-based and performance-based units was $79.3 million for fiscal year 2017 . The total fair value of restricted stock awards and units vested was $51.2 million , $26.5 million and $23.3 million for the fiscal years 2017 , 2016 and 2015 , respectively. In addition to RSUs, we also issue PRSUs with specific performance vesting criteria. These PRSUs have both a service and performance-based vesting condition and awards are divided into three equal tranches and vest based on achieving certain adjusted earnings per share (EPS) growth metrics. The service condition requires participants to be employed on May 15th of the following year once the performance condition has been met. Depending on the actual performance achieved, a participant may earn between 0% to 300% of the targeted shares for each tranche, which is determined based on a straight-line interpolation applied for the achievement between the specified performance ranges. As of September 29, 2017 , the performance condition for 75,349 target shares had been met, and 203,011 shares with a total grant date fair value of $7.1 million are expected to vest in May 2018 when the service condition is achieved. We granted 69,109 PRSUs shares during fiscal year 2017. The amount of incremental PRSU awards that could ultimately vest if all performance criteria are achieved would be 442,605 shares assuming a maximum of 300% of the targeted shares. Employee Stock Purchase Plan (ESPP) The ESPP allows eligible employees to purchase shares of our common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. In administering the ESPP, the board of directors has limited discretion to set the length of the offering periods thereunder. As of September 29, 2017 , total unrecognized compensation cost related to the ESPP was not material. In fiscal years 2017 , 2016 and 2015 , approximately 146,149 , 154,187 and 175,900 , respectively, of shares of common stock were issued under the ESPP. The 2012 Plan contains an “evergreen” provision, pursuant to which the number of shares of common stock available for issuance under the 2012 Plan can be increased on the first day of each fiscal year by the lesser of (a) 4.0% of outstanding common stock on a fully diluted basis as of the end of the immediately preceding fiscal year, (b) 1.9 million shares of common stock and (c) a lesser amount determined by the board of directors; provided, however, that any shares from any increases in previous years that are not actually issued will continue to be available for issuance under the 2012 Plan. The ESPP also contains an “evergreen” provision, pursuant to which the number of shares of common stock available for issuance under the ESPP can be increased on the first day of each fiscal year by the lesser of (a) 1.25% of outstanding common stock on a fully diluted basis as of the end of the immediately preceding fiscal year, (b) 550,000 shares of common stock and (c) a lesser amount determined by the board of directors; provided, however, that any shares from any increases in previous years that are not actually issued will continue to be available for issuance under the ESPP. In fiscal year 2017 , pursuant to the evergreen provisions, the number of shares of common stock available for issuance under the 2012 Plan and the ESPP were increased by 1.9 million shares and 550,000 shares, respectively.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Sep. 29, 2017
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY We have authorized 10 million shares of $0.001 par value preferred stock and 300 million shares of $0.001 par value common stock as of September 29, 2017 and September 30, 2016 . The outstanding shares of common stock as of September 29, 2017 and September 30, 2016 , presented in the accompanying consolidated statements of stockholders’ equity, exclude 200 and 3,300 unvested shares of restricted stock awards, respectively, issued as compensation to employees that were subject to forfeiture. Common Stock Warrants —In March 2012, we issued warrants to purchase 1,281,358 shares of common stock for $14.05 per share. The warrants expire December 21, 2020 , or earlier as per the terms of the agreement, including immediately following consummation of a sale of all or substantially all assets or capital stock or other equity securities, including by merger, consolidation, recapitalization or similar transactions. We do not currently have sufficient registered and available shares to immediately satisfy a request for registration, if such a request were made. As of September 29, 2017 , no exercise of the warrants had occurred and no request had been made to register the warrants or any underlying securities for resale by the holders. We are recording the estimated fair values of the warrants as a long-term liability in the accompanying consolidated financial statements with changes in the estimated fair value being recorded in the accompanying statements of operations.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Sep. 29, 2017
Related Party Transactions [Abstract]
Related-Party Transactions	RELATED-PARTY TRANSACTIONS GaAs Labs, LLC (GaAs Labs), a former stockholder and an affiliate of directors John and Susan Ocampo, continues to engage us to provide administrative and business development services to GaAs Labs on a time and materials basis. There are no minimum service requirements or payment obligations and the agreement may be terminated by either party with 30 days notice. In the fiscal years 2017 , 2016 and 2015 we recorded no material billings to GaAs Labs. Cadence Design Systems, Inc. (Cadence) provides us with certain engineering licenses on an ongoing basis. Geoffrey Ribar, who joined our board of directors on March 22, 2017, served as an officer of Cadence through September 30, 2017. During fiscal year 2017 , we made payments of $6.3 million to Cadence subsequent to Mr. Ribar joining the board of directors. In fiscal years 2017 and 2016 we recorded no material revenue associated with product sales to a public company with a common director. In fiscal year 2015 , we recorded revenue of $1.1 million associated with product sales to a public company with a common director.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Sep. 29, 2017
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	DISCONTINUED OPERATIONS In connection with the acquisition of AppliedMicro, we announced a plan to divest its Compute business. As of September 29, 2017, the Compute business was being actively marketed, and we expected to complete any such divestment within twelve months from the date of acquisition. We are accounting for the business as a discontinued operation. For additional information related to the divestiture of the Compute business refer to Note 27 - Subsequent Events. In August of fiscal year 2015, we sold our Automotive business to Autoliv ASP Inc. (Autoliv) as the Automotive business was not consistent with our long-term strategic vision from both a growth and profitability perspective. The agreed consideration included $82.1 million in cash paid at closing and $18.0 million payable in eighteen months pending resolution of any contingencies as part of an indemnification agreement, plus the opportunity to receive up to an additional $30.0 million in cash based on achievement of revenue-based earnout targets through 2019. Additionally, we entered into a Consulting Agreement pursuant to which we may provide Autoliv with certain non-design advisory services for a period of two years following the closing of the transaction for up to $15.0 million in cash (the Consulting Agreement), from which we have recorded $7.5 million as other income during both fiscal years 2017 and 2016. During fiscal year 2015, we recorded a pre-tax gain on the sale of the Automotive business of $ 61.8 million based on the $82.1 million received at closing on August 17, 2015, as described above. During fiscal year 2017, we received $18.0 million , the full amount of the indemnification escrow. The remainder of the consideration to be received from Autoliv, if any, including any additional amounts related to the Consulting Agreement, will be accounted for in discontinued operations when the contingencies are finalized and the proceeds, if any, become realizable. In fiscal year 2014, subsequent to closing the Mindspeed Acquisition, we divested the wireless business of Mindspeed. The operations of the wireless business are included in discontinued operations through the date of sale. There was no initial gain or loss on the sale, which closed in February 2014. The selling price of the wireless business was $12.3 million and was received upon settlement of all indemnification holdbacks during fiscal year 2014. The final settlement of $1.6 million was received in September 2015, and recorded as a pre-tax gain within discontinued operations. The accompanying consolidated statement of operations includes the following operating results related to these divested businesses (in thousands): Fiscal Years 2017 2016 2015 Revenue (1) $ 660 $ — $ 71,712 Cost of revenue (1) 2,252 — 46,931 Gross (loss) profit (1,592 ) — 24,781 Operating expenses: Research and development (1) 29,167 — 2,319 Selling, general and administrative (1) 13,840 — 2,441 Total operating expenses 43,007 — 4,760 (Loss) income from discontinued operations (1) (44,599 ) — 20,021 Other income (2) 7,500 7,500 4,000 Gain on sale (3) 18,022 308 63,321 (Loss) income before income taxes (19,077 ) 7,808 87,342 Income tax provision (benefit) — 2,786 33,211 (Loss) income from discontinued operations (19,077 ) 5,022 54,131 Above includes depreciation & amortization of (2) — — 189 Cash flow from Operating Activities (4) (42,776 ) — (8,522 ) Cash flow from Investing Activities (2) 25,522 7,500 (505 ) (1) Amounts for fiscal year 2015 are associated with the Automotive business, and amounts for fiscal year 2017 are associated with the Compute business. (2) Amounts are associated with the Automotive business. (3) Fiscal year 2015 amounts include $1.6 million associated with the Mindspeed wireless business, and the remaining amounts are associated with the Automotive business. (4) Amounts for fiscal year 2015 are associated with the Automotive business and Mindspeed wireless business, and amounts for fiscal year 2017 are associated with the Compute business. For the fiscal year ended September 29, 2017, we recorded assets held for sale of $35.6 million , which included inventory and other assets of $1.3 million , property and equipment of $7.8 million , goodwill and intangibles of $28.4 million , as well as a $2.0 million provision for disposition costs. During the same period, liabilities held for sale amounted to $2.1 million .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Sep. 29, 2017
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table set forth the computation for basic and diluted net income (loss) per share of common stock (in thousands, except per share data): Fiscal Years 2017 2016 2015 Numerator: Loss from continuing operations $ (150,416 ) $ (3,588 ) $ (5,542 ) (Loss) income from discontinued operations (19,077 ) 5,022 54,131 Net (loss) income (169,493 ) 1,434 48,589 Net (loss) income attributable to common stockholders $ (169,493 ) $ 1,434 $ 48,589 Denominator: Weighted average common shares outstanding-basic 60,704 53,364 51,146 Weighted average common shares outstanding-diluted 60,704 53,364 51,146 Common stock earnings per share-basic: Continuing operations $ (2.48 ) $ (0.07 ) $ (0.11 ) Discontinued operations (0.31 ) 0.09 1.06 Net common stock earnings per share-basic $ (2.79 ) $ 0.03 $ 0.95 Common stock earnings per share-diluted: Continuing operations $ (2.48 ) $ (0.07 ) $ (0.11 ) Discontinued operations (0.31 ) 0.09 1.06 Net common stock earnings per share-diluted $ (2.79 ) $ 0.03 $ 0.95 The table above excludes the effects of 1,877,401 , 1,855,049 and 2,055,779 shares for fiscal years 2017 , 2016 and 2015 , respectively, of potential shares of common stock issuable upon exercise of stock options, restricted stock and restricted stock units and warrants as the inclusion would be antidilutive.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Sep. 29, 2017
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION As of September 29, 2017 and September 30, 2016 , we had $7.6 million and $ 0.8 million , respectively, in unpaid amounts related to purchases of property and equipment and intangibles included in accounts payable and accrued liabilities during each period. These amounts have been excluded from the payments for purchases of property and equipment in the accompanying consolidated statements of cash flows until paid. In January 2017, we issued common stock with a fair value of $465.1 million in connection with the AppliedMicro Acquisition. This was accounted for as a non-cash transaction as no shares were purchased or sold as part of the transaction. As of September 29, 2017 , we capitalized $3.6 million relating to the construction of the 144 Chelmsford Street facility. This was accounted for as a non-cash transaction as the costs were paid by Calare Properties, Inc. The following is supplemental cash flow information regarding noncash investing and financing activities (in thousands): Fiscal Years 2017 2016 2015 Cash paid for interest $ 30,529 $ 16,335 $ 15,607 Cash paid (refunded) for income taxes $ (3,161 ) $ (373 ) $ 22,676

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Sep. 29, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The components of accumulated other comprehensive income (loss), net of income taxes, are as follows: Foreign Currency Items Other Items Total Balance - October 2, 2015 $ (2,182 ) $ (97 ) $ (2,279 ) Foreign currency translation, net of tax 11,320 — 11,320 Unrealized gain/loss on short term investments — (2 ) (2 ) Balance - September 30, 2016 9,138 (99 ) 9,039 Foreign currency translation, net of tax (5,999 ) — (5,999 ) Unrealized gain/loss on short term investments — (63 ) (63 ) Balance at September 29, 2017 $ 3,139 $ (162 ) $ 2,977

Geographic and Significant Cust

Geographic and Significant Customer Information	12 Months Ended
	Sep. 29, 2017
Segment Reporting [Abstract]
Geographic and Significant Customer Information	GEOGRAPHIC AND SIGNIFICANT CUSTOMER INFORMATION We have one reportable operating segment that designs, develops, manufactures and markets semiconductors and modules. The determination of the number of reportable operating segments is based on the chief operating decision maker’s use of financial information for the purposes of assessing performance and making operating decisions. In evaluating financial performance and making operating decisions, the chief operating decision maker primarily uses consolidated revenue, gross profit and operating income (loss). Information about our operations in different geographic regions, based upon customer locations, is presented below (in thousands): Fiscal Years Revenue by Geographic Region 2017 2016 2015 United States $ 265,038 $ 155,998 $ 152,974 China 206,136 201,911 127,428 Asia Pacific, excluding China (1) 170,826 144,872 103,941 Other Countries (2) 56,772 41,557 36,266 Total $ 698,772 $ 544,338 $ 420,609 (1) Asia Pacific represents Taiwan, Japan, Singapore, India, Thailand, South Korea, Australia, Malaysia, New Zealand, the Philippines and Vietnam. (2) No international country or region represented greater than 10% of the total revenue as of the dates presented, other than China and the Asia-Pacific region as presented above. As of September 29, September 30, Long-Lived Assets by Geographic Region United States $ 101,044 $ 79,832 Asia Pacific (1) 24,945 16,614 Other Countries (2) 5,030 2,721 Total $ 131,019 $ 99,167 (1) Asia Pacific represents Taiwan, Japan, Singapore, India, Thailand, South Korea, Australia, Malaysia, New Zealand, the Philippines, Vietnam and China. (2) No international country or region represented greater than 10% of the total net long-lived assets as of the dates presented, other than the Asia-Pacific region as presented above. The following is a summary of customer concentrations as a percentage of total sales and accounts receivable as of and for the periods presented: Fiscal Years Revenue 2017 2016 2015 Customer A 11 % 11 % 18 % Customer B 10 % 15 % 8 % Customer C 6 % 12 % 12 % September 29, September 30, Accounts Receivable Customer A 13 % 11 % Customer B 5 % 11 % Customer C 6 % 16 % Customer D 14 % 2 % No other customer represented more than 10% of revenue or accounts receivable in the periods presented in the accompanying consolidated financial statements. In fiscal years 2017 , 2016 and 2015 , our top ten customers represented an aggregate of 52% , 62% and 57% of total revenue, respectively.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Sep. 29, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	QUARTERLY FINANCIAL DATA (UNAUDITED) (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Fiscal Year Fiscal Year 2017 Revenue $ 151,752 $ 186,084 $ 194,555 $ 166,381 $ 698,772 Gross profit 78,495 68,864 92,629 86,896 326,884 (Loss) income from continuing operations (2,171 ) (134,267 ) (13,977 ) (1 ) (150,416 ) Income (loss) from discontinued operations (1) 1,206 4,136 (13,700 ) (10,719 ) (19,077 ) Per share data (2) Loss from continuing operations, basic $ (0.04 ) $ (2.21 ) $ (0.22 ) $ (0.00 ) $ (2.48 ) Income (loss) from discontinued operations, basic $ 0.02 $ 0.07 $ (0.21 ) $ (0.17 ) $ (0.31 ) Per share data (2) (3) Loss from continuing operations, diluted $ (0.04 ) $ (2.21 ) $ (0.22 ) $ (0.21 ) $ (2.48 ) Income (loss) from discontinued operations, diluted $ 0.02 $ 0.07 $ (0.21 ) $ (0.16 ) $ (0.31 ) Fiscal Year 2016 Revenue $ 115,774 $ 133,579 $ 142,288 $ 152,697 $ 544,338 Gross profit 60,318 65,525 73,962 81,804 281,609 (Loss) income from continuing operations (16,770 ) (12,045 ) 21,353 3,874 (3,588 ) Income from discontinued operations 1,199 1,396 1,199 1,228 5,022 Per share data (2) (Loss) income from continuing operations, basic $ (0.32 ) $ (0.23 ) $ 0.40 $ 0.07 $ (0.07 ) Income from discontinued operations, basic $ 0.02 $ 0.03 $ 0.02 $ 0.02 $ 0.09 Per share data (2) (3) (Loss) income from continuing operations, diluted $ (0.32 ) $ (0.23 ) $ 0.11 $ 0.07 $ (0.07 ) Income from discontinued operations, diluted $ 0.02 $ 0.03 $ 0.02 $ 0.02 $ 0.09 ____________ (1) During the second quarter of fiscal year 2017, we announced a plan to divest the Compute business of AppliedMicro, and have included the results of the Compute business as discontinued operations in each subsequent quarter. (2) Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding and included common stock equivalents in each period. Therefore, the sums of the quarters do not necessarily equal the full year earnings per share. (3) Diluted income (loss) per share for the fiscal fourth quarter 2017 and fiscal third quarter 2016 excludes $14.0 million and $15.3 million , respectively, related to warrant liability gain.

Subsequent Events

Subsequent Events	12 Months Ended
	Sep. 29, 2017
Subsequent Events [Abstract]
Subsequent Events	27. SUBSEQUENT EVENTS On October 27, 2017, we and MACOM Connectivity Solutions, LLC (MACOM Connectivity), formerly known as AppliedMicro, our wholly-owned, indirect subsidiary, entered into a Purchase Agreement (the Purchase Agreement) with Project Denver Holdings LLC (Buyer), to sell the Compute business. In consideration for the transfer and sale of the Compute business, MACOM Connectivity received an equity interest in the Buyer valued at approximately $36.5 million and representing less than 20% of the Buyer's total outstanding equity. Under the Purchase Agreement, we agreed to guarantee the financial obligations of MACOM Connectivity, thereunder and to cause the delivery of the Compute business assets transferable to Buyer according to its terms. The transactions contemplated by the Purchase Agreement closed contemporaneously with its signing, with the exception of the transfer of certain assets and entities related to the Compute business that are held outside of the United States, which will be transferred upon receipt of applicable foreign approvals.

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 29, 2017
Accounting Policies [Abstract]
Principles of Consolidation, Basis of Presentation and Reclassification	Principles of Consolidation, Basis of Presentation and Reclassification —We have one reportable segment, semiconductors and modules. The accompanying consolidated financial statements include our accounts and the accounts of our majority-owned subsidiaries. Certain prior period financial statement amounts, such as debt and leases payable and deferred revenue have been adjusted to conform to currently reported presentations . All intercompany balances and transactions have been eliminated in consolidation. We have a 52 or 53-week fiscal year ending on the Friday closest to the last day of September. The fiscal years 2017 , 2016 and 2015 included 52 weeks. To offset the effect of holidays, for fiscal years in which there are 53 weeks, we typically include the extra week arising in our fiscal years in the first quarter.
Use of Estimates	Use of Estimates —The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities during the reporting periods, the reported amounts of revenue and expenses during the reporting periods and the disclosure of contingent assets and liabilities at the date of the financial statements. On an ongoing basis, we base estimates and assumptions on historical experience, currently available information and various other factors that management believes to be reasonable under the circumstances. Actual results may differ from these estimates and assumptions.
Discontinued Operations	Discontinued Operations— In the second quarter of fiscal year 2017, we announced a plan to divest AppliedMicro's compute business (the Compute business). In the fourth quarter of fiscal year 2015, we divested our Automotive business. The operating results of these businesses are reflected in discontinued operations.
Foreign Currency Translation and Remeasurement	Foreign Currency Translation and Remeasurement —Our consolidated financial statements are presented in U.S. dollars. While the majority of our foreign operations use the U.S. dollar as the functional currency, the financial statements of our foreign operations for which the functional currency is not the U.S. dollar are translated into U.S. dollars at the exchange rates in effect at the balance sheet dates (for assets and liabilities) and at average exchange rates (for revenue and expenses). The unrealized translation gains and losses on the net investment in these foreign operations are accumulated as a component of other comprehensive income (loss). The financial statements of our foreign operations where the functional currency is the U.S. dollar, but where the underlying transactions are transacted in a different currency, are remeasured at the exchange rate in effect at the balance sheet date with respect to monetary assets and liabilities. Nonmonetary assets and liabilities, such as inventories and property and equipment and related statements of operations accounts, such as cost of revenue and depreciation, are remeasured at historical exchange rates. Revenue and expenses, other than cost of revenue, amortization and depreciation, are translated at the average exchange rate for the period in which the transaction occurred. The net gains and losses on foreign currency remeasurement are reflected in selling, general and administrative expense in the accompanying consolidated statements of operations. Net foreign exchange transaction gains and losses for all periods presented were immaterial.
Cash and Cash Equivalents	Cash and Cash Equivalents —Cash equivalents are primarily composed of short-term, highly-liquid instruments with an original maturity of three months or less and consist primarily of money market funds and commercial paper.
Investments	Investments —We classify our investments as available-for-sale. Our investments classified as available-for-sale are recorded at fair value based upon third party pricing at period end. Unrealized gains and losses that are deemed temporary in nature are recorded in accumulated other comprehensive income and loss as a separate component of stockholders’ equity. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums and discounts are amortized (accreted) over the life of the related security as an adjustment to its yield. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of investments sold.
Inventories	Inventories —Inventories are stated at the lower of cost or market. We use a combination of standard cost and moving weighted-average cost methodologies to determine the cost basis for our inventories, approximating a first-in, first-out basis. The standard cost of finished goods and work-in-process inventory is composed of material, labor and manufacturing overhead, which approximates actual cost. In addition to stating inventory at the lower of cost or market, we also evaluate inventory each reporting period for excess quantities and obsolescence, establishing reserves when necessary based upon historical experience, assessment of economic conditions and expected demand. Once recorded, these reserves are considered permanent adjustments to the carrying value of inventory.
Property and Equipment	Property and Equipment —Property and equipment are stated at cost, less accumulated depreciation and amortization. Expenditures for maintenance and repairs are charged to expense as incurred, whereas major improvements that significantly extend the useful life of the assets are capitalized as additions to property and equipment. Property and equipment are depreciated or amortized using the straight-line method over the following estimated useful lives: Asset Classification Estimated Useful Life In Years Buildings and improvements 20 – 40 Machinery and equipment 2 – 7 Computer equipment and software 2 – 5 Furniture and fixtures 7 – 10 Leasehold improvements Shorter of useful life or term of lease
Goodwill and Indefinite-lived Intangible Assets	Goodwill and Indefinite-Lived Intangible Assets —We have goodwill and certain intangible assets with indefinite lives which are not subject to amortization; these are reviewed for impairment annually as of the end of our August fiscal month end and more frequently if events or changes in circumstances indicate that the assets may be impaired. For our assessment of goodwill impairment, we compare the carrying value of the reporting unit to the fair value of the Company. For our assessment of in-service indefinite-lived assets we compare the carrying value of the asset to the estimated fair value of the asset. For indefinite-lived assets not in service, such as in-process research and development, we perform both qualitative and quantitative assessments using an assumption of "more likely than not" to determine if there are any impairment indicators. If impairment exists, a loss is recorded to write down the value of the assets to their implied fair values. During the fiscal year ended September 29, 2017 , we recorded impairment charges of $4.4 million related to indefinite-lived intangible assets. S ee Note 16 - Intangible Assets , for further detail of these impairment charges.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets —Long-lived assets include property and equipment and definite-lived intangible assets subject to amortization. We evaluate long-lived assets for recoverability when events or changes in circumstances indicate that their carrying amounts may not be recoverable. Circumstances which could trigger a review include, but are not limited to, significant decreases in the market price of the asset or asset group, significant adverse changes in the business climate or legal factors, the accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of the asset, current period cash flow or operating losses combined with a history of losses or a forecast of continuing losses associated with the use of the asset and a current expectation that the asset will more likely than not, be sold or disposed of significantly before the end of its previously estimated useful life. In evaluating a long-lived asset for recoverability, we estimate the undiscounted cash flows expected to result from our use and eventual disposition of the asset. If the sum of the expected undiscounted cash flows is less than the carrying amount of the asset, an impairment loss, equal to the excess of the carrying amount over the fair value of the asset, is recognized. In fiscal year 2016 we recorded impairment charges of $ 13.8 million related to our strategic decision to exit a product line and end programs associated with our GaN-on Silicon Carbide (GaN-on-SiC) license and technology transfer. There were no impairments of definite life long-lived assets in any other periods presented. Intangible assets related to in-process research and development acquired are not amortized until the underlying asset begins revenue-generating activity, at which time it is amortized over its estimated useful life. Intangibles related to abandoned in-process research and development projects are expensed in the period the project is abandoned.
Other Intangible Assets	Other Intangible Assets —Our other intangible assets, including acquired technology and customer relationships, are definite-lived assets and are subject to amortization. We amortize definite-lived assets over their estimated useful lives, which range from five to fourteen years, generally based on the pattern over which we expect to receive the economic benefit from these assets.
Revenue Recognition	Revenue Recognition —We recognize revenue when: (i) persuasive evidence of an arrangement exists; (ii) delivery or services have been rendered; (iii) the price is fixed or determinable; and (iv) collectability is reasonably assured. We recognize revenue with the transfer of title and risk of loss and provide for reserves for returns and other allowances. We generally do not provide customers other than distributors the right to return product, with the exception of warranty related matters. Shipping and handling fees billed to customers are recorded as revenue while the related costs are classified as a component cost of revenue. We provide warranties for certain products and accrue the costs of warranty claims in the period the related revenue is recorded. Prior to fiscal year 2015, we had concluded that we had insufficient information as well as limited experience in estimating the effect of the right of distributors to return product and price protection and, accordingly, used the sell through approach of revenue recognition. Under this approach, we would recognize revenue from sales after the distributor resold the product to its end customer (the sell through basis). After concluding an extensive three year study of distributor related transactions, we completed an evaluation of our revenue recognition policy and concluded that it was appropriate to recognize revenue to distributors at the time of shipment to the distributor (sell-in basis). During fiscal year 2015, we concluded that we had sufficient data to predict future price adjustments from distributors and had a basis of being able to reasonably estimate these future price adjustments. Accordingly, on a consolidated basis, revenue from distribution customers was impacted by a change in estimate. Revenues from distributors accounted for approximately 10-15% of total consolidated revenue at that time. The terms of certain agreements with distribution customers provide for rights of return and compensation credits until such time as our products are sold by the distributors to their end customers. We have agreements with some distribution customers for various programs, including compensation, volume-based pricing, obsolete inventory, new products and stock rotation. Sales to these distribution customers, as well as the existence of compensation programs, are in accordance with terms set forth in written agreements with these distribution customers. In general, credits allowed under these programs are capped based upon individual distributor agreements. We record charges associated with these programs as a reduction of revenue at the time of sale with a corresponding adjustment to accounts receivable based upon historical activity. Our policy is to use a 12 months rolling historical experience rate and an estimated general reserve percentage in order to estimate the necessary allowance to be recorded. During the fiscal year ended October 2, 2015, we recorded corresponding adjustments related to this change in estimate to recognize previously deferred revenues. The full-year impact of this change in estimate resulted in additional revenue of $17.4 million and a net income of $7.7 million , or $0.15 earnings per share during fiscal year 2015. We also established a new reserve of $6.0 million for the fiscal year ended October 2, 2015 related to future rebates and returns under various programs associated with our distributor agreements.
Research and Development Costs	Research and Development Costs —Costs incurred in the research and development of products are expensed as incurred.
Income Taxes	Income Taxes —Deferred tax assets and liabilities are recognized based on temporary differences between the financial reporting and income tax bases of assets and liabilities, using rates anticipated to be in effect when such temporary differences reverse. A valuation allowance against net deferred tax assets is required if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. We provide reserves for potential payments of tax to various tax authorities related to uncertain tax positions and other issues. Reserves are based on a determination of whether and how much of a tax benefit is taken by us in our tax filings or positions that are more likely than not to be realized following an examination by taxing authorities. We recognize the financial statement benefit of an uncertain tax position only after considering the probability that a tax authority would sustain the position in an examination. For tax positions meeting a “more-likely-than-not” threshold, the amount recognized in the financial statements is the benefit expected to be realized upon settlement with the tax authority. For tax positions not meeting the threshold, no financial statement benefit is recognized. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of income tax expense.
Earnings Per Share	Earnings Per Share —Basic net (loss) income per share is computed by dividing net (loss) income by the weighted-average number of common shares outstanding during the period, excluding the dilutive effect of common stock equivalents. Diluted net income (loss) per share reflects the dilutive effect of common stock equivalents, such as stock options, warrants and restricted stock units, using the treasury stock method.
Fair Value Measurements	Fair Value Measurements —Financial assets and liabilities are measured at fair value. Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability at the measurement date under current market conditions in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, we group financial assets and liabilities in a three-tier fair value hierarchy, according to the inputs used in measuring fair value as follows: Level 1—observable inputs such as quoted prices in active markets for identical assets and liabilities; Level 2—inputs other than quoted prices in active markets that are observable either directly or indirectly, such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical assets and liabilities in markets that are not active and model-based valuation techniques for which significant assumptions are observable in active markets; and, Level 3—unobservable inputs for which there is little or no market data, requiring us to develop our own assumptions for model-based valuation techniques. This hierarchy requires us to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Money market funds are actively traded and consist of highly liquid investments with original maturities of 90 days or less. They are measured at their net asset value (NAV) and classified as Level 1. Corporate and agency bonds and commercial paper are categorized as Level 2 assets except where sufficient quoted prices exist in active markets, in which case such securities are categorized as Level 1 assets. These securities are valued using third-party pricing services. These services may use, for example, model-based pricing methods that utilize observable market data as inputs. We generally use quoted prices for recent trading activity of assets with similar characteristics to the debt security or bond being valued. The securities and bonds priced using such methods are generally classified as Level 2. Broker dealer bids or quotes on securities with similar characteristics may also be used. The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to the short-term nature of these assets and liabilities.
Contingent Consideration	Contingent Consideration —We estimate and record at the acquisition date, the fair value of contingent consideration making up part of the purchase price consideration for acquisitions. Additionally, at each reporting period, we estimate the change in the fair value of contingent consideration and any change in fair value is recognized in the consolidated statements of operations. We estimate the fair value of contingent consideration by discounting the associated expected cash flows, using a probability-weighted, discounted cash flow model. The estimate of the fair value of contingent consideration requires subjective assumptions to be made regarding future operating results, discount rates and probabilities assigned to various potential operating result scenarios.
Share-Based Compensation	Share-Based Compensation —We account for all share-based compensation arrangements using the fair value method. We recognize compensation expense over the requisite service period of the award, which is generally the vesting period, using the straight-line method and providing that the minimum amount of compensation recorded is equal to the vested portion of the award. We record the expense in the consolidated statements of operations in the same manner in which the award recipients’ salary costs are classified. For restricted stock awards with service conditions we use the closing stock price on the date of grant to estimate the fair value of the awards. We use the Black-Scholes option-pricing model to estimate the fair value of stock options with service and performance conditions, inclusive of assumptions for risk-free interest rates, dividends, expected terms and estimated volatility. We derive the risk-free interest rate assumption from the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to the expected term of the award being valued. We base the assumed dividend yield on its expectation of not paying dividends in the foreseeable future. We calculate the weighted-average expected term of the options using the simplified method, which is a method of applying a formula that uses the vesting term and the contractual term to compute the expected term of a stock option. The decision to use the simplified method is based on a lack of relevant historical data, due to our limited operating experience. In addition, due to our limited historical data, we incorporate the historical volatility of comparable companies with publicly available share prices to determine estimated volatility. The accounting for share-based compensation requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Share-based awards that are settled in cash are recorded as liabilities. The measurement of the liability and compensation cost for these awards is based on the fair value of the award, and is recorded in operating income over the award’s vesting period. Changes in our payment obligation prior to the settlement date of a stock-based award are recorded as compensation cost in operating income in the period of the change. The final payment amount for such awards is established on the date of the exercise of the award by the employee.
Guarantees and Indemnification Obligations	Guarantees and Indemnification Obligations —We enter into agreements in the ordinary course of business with, among others, customers, distributors and original equipment manufacturers (OEM). Most of these agreements require us to indemnify the other party against third-party claims alleging that a Company product infringes a patent and/or copyright. Certain agreements in which we grant limited licenses to Company intellectual property require us to indemnify the other party against third-party claims alleging that the use of the licensed intellectual property infringes a third-party's intellectual property. Certain of these agreements require us to indemnify the other party against certain claims relating to property damage, personal injury or the acts or omissions, its employees, agents or representatives. In addition, from time to time, we have made certain guarantees in the form of warranties regarding the performance of Company products to customers. We have agreements with certain vendors, creditors, lessors and service providers pursuant to which we have agreed to indemnify the other party for specified matters, such as acts and omissions, its employees, agents or representatives. We have procurement or license agreements with respect to technology used in our products and agreements in which we obtain rights to a product from an OEM. Under some of these agreements, we have agreed to indemnify the supplier for certain claims that may be brought against such party with respect to our acts or omissions relating to the supplied products or technologies. Our certificate of incorporation and agreements with certain of our directors and officers and certain of our subsidiaries’ directors and officers provide them indemnification rights, to the extent legally permissible, against liabilities incurred by them in connection with legal actions in which they may become involved by reason of their service as a director or officer. As a matter of practice, we have maintained director and officer liability insurance coverage, including coverage for directors and officers of acquired companies. We have not experienced any losses related to these indemnification obligations in any period presented and no claims with respect thereto were outstanding as of September 29, 2017 and September 30, 2016 . We do not expect significant claims related to these indemnification obligations and, consequently, have concluded that the fair value of these obligations is negligible. No liabilities related to indemnification liabilities have been established.
Recent Accounting Pronouncements	Recent Accounting Pronouncements —In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers: Deferral of the Effective Date , which delayed the effective date of the new standard from January 1, 2017 to January 1, 2018. The FASB also agreed to allow entities to choose to adopt the standard as of the original effective date. We are still in the process of completing our gap analysis on the impact of this guidance. At this time, with the consideration that we currently recognize distributor revenue based on sell-in accounting, we do not expect the adoption of Topic 606 to have a material impact on our financial position and results of operations. The standard permits the use of either the retrospective or cumulative effect transition method, and we are currently evaluating the method of adoption. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern , which provides guidance on management's responsibility to assess whether there is substantial doubt about a company's ability to continue as a going concern. The guidance is effective for annual periods ending after December 15, 2016 and interim periods thereafter. As of September 29, 2017, we have adopted this guidance and performed the required assessment which did not have a significant impact on our consolidated financial statement disclosures. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Liabilities . This update makes amendments to the guidance in U.S. GAAP on the classification and measurement of financial instruments. The new standard significantly revises an entity's accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. It also amends certain disclosure requirements associated with the fair value of financial instruments. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases , which increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Certain qualitative and quantitative disclosures are required, as well as a retrospective recognition and measurement of impacted leases. The new guidance is effective for fiscal years and interim periods within those years beginning after December 15, 2018, with early adoption permitted. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures and we anticipate that this new guidance will materially impact our financial statements as we have a significant number of operating leases. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payment transactions for both public and nonpublic entities, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. Early adoption is permitted and the updated standard must be adopted no later than our fiscal first quarter of fiscal year 2018. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments . This update amends the guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For available for sale debt securities, credit losses should be measured in a manner similar to current GAAP; however, this update will require that credit losses be presented as an allowance rather than as a write-down. ASU 2016-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments . This update addresses debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures. In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory . This update amends the guidance on recognizing the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendment eliminates the exception for an intra entity transfer of an asset other than inventory. ASU 2016-16 is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. We are evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 29, 2017
Accounting Policies [Abstract]
Schedule of Estimated Useful Life	Property and equipment are depreciated or amortized using the straight-line method over the following estimated useful lives: Asset Classification Estimated Useful Life In Years Buildings and improvements 20 – 40 Machinery and equipment 2 – 7 Computer equipment and software 2 – 5 Furniture and fixtures 7 – 10 Leasehold improvements Shorter of useful life or term of lease

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Sep. 29, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table summarizes the total estimated acquisition consideration (in thousands): Cash consideration paid to AppliedMicro common stockholders $ 287,060 Common stock issued (9,544,125 shares of our common stock at $47.53 per share) 453,632 Equity consideration for vested "in-the-money" stock options and unvested restricted stock units 2,143 Fair value of the replacement equity awards attributable to pre-acquisition service 9,307 Total consideration paid, less cash acquired $ 752,142
Allocation of Purchase Price	The final allocation of purchase price as of December 30, 2016, is as follows (in thousands): Preliminary Allocation as of September 30, 2016 Allocation Adjustments Final Allocation Current assets $ 10,445 $ — $ 10,445 Intangible assets 45,650 — 45,650 Other assets 3,317 — 3,317 Total assets acquired 59,412 — 59,412 Debt 11,627 — 11,627 Deferred income taxes 11,658 (106 ) 11,552 Other liabilities 3,968 326 4,294 Total liabilities assumed 27,253 220 27,473 Net assets acquired 32,159 (220 ) 31,939 Consideration: Cash paid upon closing, net of cash acquired 47,517 — 47,517 Goodwill $ 15,358 $ 220 $ 15,578 The final allocation of purchase price as of January 1, 2016, was as follows (in thousands): Preliminary Allocation as of October 2, 2015 Allocation Adjustments Final Allocation Current assets $ 23,674 $ (1,100 ) $ 22,574 Intangible assets 136,900 400 137,300 Other assets 9,194 — 9,194 Total assets acquired 169,768 (700 ) 169,068 Debt 2,535 — 2,535 Deferred income taxes 33,345 99 33,444 Other liabilities 13,106 — 13,106 Total liabilities assumed 48,986 99 49,085 Net assets acquired 120,782 (799 ) 119,983 Consideration: Cash paid upon closing, net of cash acquired 208,352 — 208,352 Goodwill $ 87,570 $ 799 $ 88,369 The final allocation of purchase price as of December 30, 2016, is as follows (in thousands): Preliminary Allocation as of September 30, 2016 Allocation Adjustments Final Allocation Current assets $ 12,614 $ — $ 12,614 Intangible assets 20,900 — 20,900 Other assets 3,089 — 3,089 Total assets acquired 36,603 — 36,603 Other liabilities 7,201 — 7,201 Total liabilities assumed 7,201 — 7,201 Net assets acquired 29,402 — 29,402 Consideration: Cash paid upon closing, net of cash acquired 37,125 — 37,125 Goodwill $ 7,723 $ — $ 7,723 The preliminary allocation of purchase price as of September 29, 2017 is as follows (in thousands): Preliminary Allocation Allocation Adjustments Adjusted Allocation March 31, 2017 September 29, 2017 Current assets $ 70,338 $ 96 $ 70,434 Intangible assets 410,348 2,500 412,848 Assets held for sale 32,458 8,486 40,944 Other assets 13,504 (3,704 ) 9,800 Total assets acquired 526,648 7,378 534,026 Liabilities held for sale 4,444 — 4,444 Other liabilities 17,890 (263 ) 17,627 Total liabilities assumed 22,334 (263 ) 22,071 Net assets acquired 504,314 7,641 511,955 Consideration: Cash paid upon closing 230,298 — 230,298 Common stock issued 455,775 — 455,775 Equity instruments issued 9,307 — 9,307 Total consideration $ 695,380 $ — $ 695,380 Goodwill $ 191,066 $ (7,641 ) $ 183,425 The preliminary allocation of purchase price as of September 29, 2017 is as follows (in thousands): Preliminary Allocation September 29, 2017 Current assets $ 7,375 Intangible assets 19,000 Other assets 3,301 Total assets acquired 29,676 Current liabilities 2,169 Other liabilities 190 Total liabilities assumed 2,359 Net assets acquired 27,317 Consideration: Cash paid upon closing, net of cash acquired 33,500 Goodwill $ 6,183
Components of Acquired Intangible Assets on a Preliminary Basis	The components of the acquired intangible assets on a preliminary basis were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 1,000 7 Customer relationships 19,900 10 $ 20,900 The components of the acquired intangible assets on a preliminary basis were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 9,400 7 Customer relationships 36,250 10 $ 45,650 The components of the acquired intangible assets were as follows (in thousands): Amount Useful Lives (Years) Developed technology $ 17,500 7 Customer relationships 119,800 10 $ 137,300 The components of the acquired intangible assets were as follows (in thousands): Included In Assets Held For Sale Included In Retained Business Useful Lives (Years) Developed technology $ 9,600 $ 78,448 7 years Customer relationships — 334,400 14 years $ 9,600 $ 412,848
Summary of Unaudited Supplemental Pro Forma Data	The following is a summary of BinOptics revenue and earnings included in our consolidated statements of operations for the fiscal year ended October 2, 2015 (in thousands): Fiscal Year Ended October 2, 2015 Revenue $ 61,549 Income before income taxes 354 This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. October 2, 2015 Revenue $ 428,440 Net income from continuing operations (3,489 ) This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 30, 2016 October 2, 2015 Revenue $ 551,964 $ 444,991 Net (loss) income (3,324 ) 36,715 This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 30, 2016 October 2, 2015 Revenue $ 553,174 $ 459,048 Net income 1,183 45,107 The following is a summary of AppliedMicro revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 29, 2017 (in thousands): Amount Revenue $ 110,117 Loss from continuing operations (27,222 ) Loss from discontinued operations (44,599 ) This pro forma data is presented for informational purposes only and does not purport to be indicative of our future results of operations. Fiscal Year Ended September 29, 2017 September 30, 2016 Revenue $ 755,728 $ 707,299 Loss from continuing operations (104,828 ) (53,613 ) Loss from discontinued operations (43,734 ) (72,730 ) The following is a summary of FiBest revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 30, 2016 (in thousands): Amount Revenue $ 30,540 Loss before income taxes (4,616 ) The following is a summary of Metelics revenue and earnings included in our accompanying consolidated statements of operations for the fiscal year ended September 30, 2016 (in thousands): Amount Revenue $ 33,552 Income before income taxes 3,372

Investments (Tables)

Investments (Tables)	12 Months Ended
	Sep. 29, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Available for Sale Investments	The amortized cost, gross unrealized holding gains or losses and fair value of our available-for-sale investments by major investments type as of September 29, 2017 and September 30, 2016 are summarized in the tables below (in thousands): September 29, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Corporate bonds $ 26,366 $ 10 $ (166 ) $ 26,210 Commercial paper 57,943 4 (36 ) 57,911 Total investments $ 84,309 $ 14 $ (202 ) $ 84,121 September 30, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Corporate bonds $ 14,894 $ 9 $ (104 ) $ 14,799 Commercial paper 2,978 — (3 ) 2,975 Agency bonds 6,004 1 (3 ) 6,002 Total investments $ 23,876 $ 10 $ (110 ) $ 23,776
Summary of Contractual Maturities of Investments	The contractual maturities of available-for-sale investments were as follows (in thousands): September 29, 2017 Less than 1 year $ 60,433 Over 1 year 23,688 Total investments $ 84,121

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Sep. 29, 2017
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis consist of the following (in thousands): September 29, 2017 Fair Value Active Markets for Identical Assets (Level 1) Observable Inputs (Level 2) Unobservable Inputs (Level 3) Assets Money market funds $ 36 $ 36 $ — $ — Commercial paper 57,911 — 57,911 — Corporate bonds 26,210 — 26,210 — Total assets measured at fair value $ 84,157 $ 36 $ 84,121 $ — Liabilities Contingent consideration $ 1,679 $ — $ — $ 1,679 Common stock warrant liability 40,775 — — 40,775 Total liabilities measured at fair value $ 42,454 $ — $ — $ 42,454 September 30, 2016 Fair Value Active Markets for Identical Assets (Level 1) Observable Inputs (Level 2) Unobservable Inputs (Level 3) Assets Money market funds $ 1,172 $ 1,172 $ — $ — Commercial paper 102,928 — 102,928 — US treasuries and agency bonds 6,002 — 6,002 — Corporate bonds 14,799 — 14,799 — Total assets measured at fair value $ 124,901 $ 1,172 $ 123,729 $ — Liabilities Contingent consideration $ 848 $ — $ — $ 848 Warrant liability 38,253 — — 38,253 Total liabilities measured at fair value $ 39,101 $ — $ — $ 39,101
Quantitative Information Used in Fair Value Calculation of Level 3 Liabilities	The quantitative information utilized in the fair value calculation of our Level 3 liabilities are as follows: Liabilities Valuation Technique Unobservable Input September 29, 2017 September 30, 2016 Contingent consideration Discounted cash flow Discount rate 9.2% 12.9% Probability of achievement 70% - 100% 75% - 100% Timing of cash flows 2 - 8 months 1 year Warrant liability Black-scholes model Volatility 44.9% 43.2% Discount rate 1.62% 1.14% Expected life 3.2 years 4.2 years Exercise price $14.05 $14.05 Stock price $44.61 $42.34 Dividend rate —% —%
Changes in Assets with Inputs Classified within Level 3 of Fair Value	The changes in assets and liabilities with inputs classified within Level 3 of the fair value hierarchy consist of the following (in thousands): Fiscal Year 2017 September 30, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 29, Contingent consideration $ 848 $ 180 $ 1,701 $ (1,050 ) $ — $ 1,679 Warrant liability $ 38,253 $ 2,522 $ — $ — $ — $ 40,775 Fiscal Year 2016 October 2, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 30, Contingent consideration $ 1,150 $ 98 $ — $ (400 ) $ — $ 848 Warrant liability $ 21,822 $ 16,431 $ — $ — $ — $ 38,253 Fiscal Year 2015 October 3, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 October 2, Trading securities $ 250 $ — $ 500 $ (750 ) $ — $ — Contingent consideration $ 820 $ 330 $ — $ — $ — $ 1,150 Warrant liability $ 15,802 $ 6,020 $ — $ — $ — $ 21,822
Changes in Liabilities with Inputs Classified within Level 3 of Fair Value	The changes in assets and liabilities with inputs classified within Level 3 of the fair value hierarchy consist of the following (in thousands): Fiscal Year 2017 September 30, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 29, Contingent consideration $ 848 $ 180 $ 1,701 $ (1,050 ) $ — $ 1,679 Warrant liability $ 38,253 $ 2,522 $ — $ — $ — $ 40,775 Fiscal Year 2016 October 2, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 September 30, Contingent consideration $ 1,150 $ 98 $ — $ (400 ) $ — $ 848 Warrant liability $ 21,822 $ 16,431 $ — $ — $ — $ 38,253 Fiscal Year 2015 October 3, Net Realized/Unrealized Losses (Gains) Included in Earnings Purchases and Issuances Sales and Settlements Transfers in and/or (out) of Level 3 October 2, Trading securities $ 250 $ — $ 500 $ (750 ) $ — $ — Contingent consideration $ 820 $ 330 $ — $ — $ — $ 1,150 Warrant liability $ 15,802 $ 6,020 $ — $ — $ — $ 21,822

Accounts Receivables Allowanc40

Accounts Receivables Allowances (Tables)	12 Months Ended
	Sep. 29, 2017
Receivables [Abstract]
Rollforward of Accounts Receivable Allowances	Summarized below is the activity in our accounts receivable allowances including customer returns, doubtful accounts and other items as follows (in thousands): Fiscal Year 2017 2016 2015 Balance - beginning of year $ 3,279 $ 5,745 $ 725 Provision, net 29,512 10,453 11,010 Charge-offs (23,381 ) (12,919 ) (5,990 ) Balance - end of year $ 9,410 $ 3,279 $ 5,745

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Sep. 29, 2017
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consist of the following (in thousands): September 29, 2017 September 30, 2016 Raw materials $ 78,999 $ 67,378 Work-in-process 13,962 9,157 Finished goods 43,113 38,400 Total $ 136,074 $ 114,935

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Sep. 29, 2017
Property, Plant and Equipment [Abstract]
Components of Property, Plant and Equipment	Property, plant and equipment consist of the following (in thousands): September 29, September 30, Land, buildings and improvements $ — $ 12,572 Construction in process 22,195 9,415 Machinery and equipment 160,955 126,432 Leasehold improvements 13,809 12,152 Furniture and fixtures 2,078 1,469 Capital lease assets 20,410 3,207 Computer equipment and software 16,539 12,954 Total property and equipment 235,986 178,201 Less accumulated depreciation and amortization (104,967 ) (79,034 ) Property and equipment — net $ 131,019 $ 99,167

Debt (Tables)

Debt (Tables)	12 Months Ended
	Sep. 29, 2017
Debt Disclosure [Abstract]
Schedule of Remained Outstanding on Term Loans	As of September 29, 2017 , the following remained outstanding on the Term Loans: Principal balance $ 686,741 Unamortized discount (5,835 ) Total term loans 680,906 Current portion 6,885 Long-term, less current portion $ 674,021
Schedule of Minimum Principal Payments under Term Loans	As of September 29, 2017 , the minimum principal payments under the Term Loans in future fiscal years were as follows (in thousands): 2018 $ 6,885 2019 6,885 2020 6,885 2021 6,885 2022 6,885 Thereafter 652,316 Total $ 686,741

Capital Lease and Financing O44

Capital Lease and Financing Obligations (Tables)	12 Months Ended
	Sep. 29, 2017
Capital Lease and Financing Obligations [Abstract]
Schedule of Future Minimum Lease Payments for Capital Leases	As of September 29, 2017 , future minimum payments under capital lease obligations and financing obligations related to the Leases were as follows (in thousands): Fiscal year ending: Amount 2018 $ 1,895 2019 1,791 2020 1,619 2021 1,485 2022 1,276 Thereafter 19,264 Total minimum capital lease payments $ 27,330 Less amount representing interest $ (14,698 ) Present value of net minimum capital lease payments $ 12,632

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 29, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments for Operating Leases	Future minimum lease payments for the next five fiscal years as of September 29, 2017 , are as follows (in thousands): 2018 $ 11,116 2019 9,001 2020 5,985 2021 3,828 2022 3,113 Thereafter 7,999 Total minimum lease payments $ 41,042

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Sep. 29, 2017
Other Liabilities Disclosure [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands): September 29, September 30, Compensation and benefits $ 32,505 $ 32,563 Distribution costs 5,777 3,584 Income taxes payable 4,184 — Product warranty 3,672 1,039 Professional fees 2,140 1,706 Deferred revenue 1,994 340 Contingent consideration 1,679 848 Rent and utilities 1,257 1,310 Purchase price holdback 1,000 — Asset retirement obligations 959 2,932 Restructuring costs 627 3,104 Interest payable 532 4,314 Other 3,911 2,628 Total $ 60,237 $ 54,368

Restructurings (Tables)

Restructurings (Tables)	12 Months Ended
	Sep. 29, 2017
Restructuring and Related Activities [Abstract]
Summary of Costs Related to Restructuring Actions	The following is a summary of the costs incurred and remaining balances included in accrued expenses related to restructuring actions taken (in thousands): Total Balance - October 3, 2014 $ 801 Current period charges 1,280 Payments (1,138 ) Balance - October 2, 2015 943 Current period charges 3,465 Payments (1,304 ) Balance - September 30, 2016 3,104 Current period charges 2,744 Payments (5,221 ) Balance at September 29, 2017 $ 627

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Sep. 29, 2017
Guarantees [Abstract]
Schedule of Product Warranty Liability Activity	Product warranty liability activity is as follows (in thousands): Fiscal Years 2017 2016 2015 Balance — beginning of year $ 1,039 $ 656 $ 446 Acquired 952 413 50 Provisions 1,737 (30 ) 160 Direct charges (56 ) — — Balance — end of year $ 3,672 $ 1,039 $ 656

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Sep. 29, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Amortization Expense Related to Amortizable Intangible Assets	Amortization expense related to intangible assets is as follows (in thousands): Fiscal Years 2017 2016 2015 Cost of revenue $ 30,286 $ 26,615 $ 27,285 Selling, general and administrative 35,456 23,640 11,695 Total $ 65,742 $ 50,255 $ 38,980
Summary of Intangible Assets	Intangible assets consist of the following (in thousands): September 29, September 30, Acquired technology $ 251,655 $ 165,397 Customer relationships 556,648 207,674 In-process research and development — 8,000 Trade name 3,400 3,400 Total 811,703 384,471 Less accumulated amortization (190,611 ) (124,869 ) Intangible assets — net $ 621,092 $ 259,602
Summary of Activity in Intangible Assets and Goodwill	A summary of the activity in intangible assets and goodwill follows (in thousands): Intangible Assets Total Acquired Customer In-Process Research and Development Trade Name Goodwill Balance at October 2, 2015 $ 318,006 $ 162,536 $ 144,070 $ 8,000 $ 3,400 $ 93,346 Acquired 65,350 10,400 54,950 — — 20,412 Fair value adjustment 1,678 78 1,600 — — 3,475 Currency translation adjustments 8,857 1,803 7,054 — — 2,791 Impairments of intangible assets (10,088 ) (10,088 ) — — — — Other intangibles purchased 668 668 — — — — Balance at September 30, 2016 384,471 165,397 207,674 8,000 3,400 120,024 Acquired 436,181 83,518 352,663 — — 195,145 Placed in service — 3,648 — (3,648 ) — — Fair value adjustment — — — — — 220 Currency translation adjustments (4,597 ) (908 ) (3,689 ) — — (1,624 ) Impairments of intangible assets (4,352 ) — — (4,352 ) — — Balance at September 29, 2017 $ 811,703 $ 251,655 $ 556,648 $ — $ 3,400 $ 313,765
Summary of Estimated Amortization of Intangible Assets in Future Fiscal Years	As of September 29, 2017 , our estimated amortization of our intangible assets in future fiscal years, subject to the completion of the purchase price allocation for the AppliedMicro, Picometrix, Antario and TPC acquisitions, was as follows (in thousands): 2018 2019 2020 2021 2022 Thereafter Amortization expense $ 82,798 90,429 88,030 79,161 65,468 211,806

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 29, 2017
Income Tax Disclosure [Abstract]
Components of Deferred Tax Assets and Liabilities	The components of our deferred tax assets and liabilities are as follows (in thousands): September 29, September 30, Deferred tax assets (liabilities): Federal and foreign net operating losses and credits $ 396,871 $ 85,256 Intangible assets (180,544 ) (49,725 ) Property and equipment (1,045 ) (2,730 ) Other non-current deferred tax assets 20,756 21,855 Discontinued operations — 9,100 Deferred compensation 9,291 5,545 Deferred gain 14,853 19,011 Valuation allowance (274,406 ) (10,471 ) Total deferred tax (liability) asset $ (14,224 ) $ 77,841
Summary of Domestic and Foreign Income (Loss) from Continuing Operations Before Taxes	The domestic and foreign income (loss) from continuing operations before taxes were as follows (in thousands): Fiscal Years 2017 2016 2015 United States $ (111,432 ) $ (46,593 ) $ (34,251 ) Foreign 61,927 25,022 18,851 (Loss) income from operations before income taxes $ (49,505 ) $ (21,571 ) $ (15,400 )
Components of Provision (Benefit) for Income Taxes	The components of the provision (benefit) for income taxes are as follows (in thousands): Fiscal Years 2017 2016 2015 Current: Federal $ 100 $ (5,861 ) $ (19,015 ) State 225 (766 ) 688 Foreign 7,307 906 1,092 Current provision (benefit) 7,632 (5,721 ) (17,235 ) Deferred: Federal (42,637 ) (8,163 ) 10,845 State (4,037 ) (502 ) (4,131 ) Foreign (466 ) (2,603 ) (1,302 ) Change in valuation allowance 140,419 (994 ) 1,965 Deferred provision (benefit) 93,279 (12,262 ) 7,377 Total provision (benefit) $ 100,911 $ (17,983 ) $ (9,858 )
Reconciliation of Effective Tax Rates	Our effective tax rates differ from the federal and statutory rate as follows: Fiscal Years 2017 2016 2015 Federal statutory rate 35.0% 35.0% 35.0% Foreign rate differential 31.9 40.1 30.5 State taxes net of federal benefit 0.2 1.0 3.5 Warrant liabilities (1.8) (26.7) (13.7) Change in valuation allowance (270.0) 3.0 (6.0) Research and development credits 12.8 16.9 16.1 Correction of prior period — 18.3 — Provision to return adjustments (4.0) 3.5 9.9 Nondeductible compensation expense (4.1) (9.2) (8.9) Nondeductible legal fees (3.9) (1.8) (4.1) Other permanent differences 0.1 3.3 1.6 Effective income tax rate (203.8)% 83.4% 63.9%
Activity Related to Unrecognized Tax Benefits	Activity related to unrecognized tax benefits is as follows (in thousands): Amount Balance - October 2, 2015 (1,670 ) Additions based on tax positions — Reductions based on tax positions — Balance - September 30, 2016 $ (1,670 ) Additions based on tax positions — Reductions based on tax positions — Balance at September 29, 2017 $ (1,670 )
Summary of Fiscal Tax Years Examination by Jurisdictions	A summary of the fiscal tax years that remain subject to examination, as of September 29, 2017 , for the Company’s significant tax jurisdictions are: Jurisdiction Tax Years Subject to Examination United States—federal 2013 - forward United States—various states 2013 - forward Ireland 2012 - forward

Share - Based Compensation Pl51

Share - Based Compensation Plans (Tables)	12 Months Ended
	Sep. 29, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Effects of Stock-Based Compensation Expense Related to Stock-Based Awards to Employees and Nonemployees	The following table shows a summary of share-based compensation expense included in the Consolidated Statement of Operations during the periods presented (in thousands): Fiscal Years 2017 2016 2015 Cost of revenue $ 3,189 $ 2,150 $ 1,949 Research and development 10,565 6,568 5,447 Selling, general and administrative 22,581 18,236 12,039 Total $ 36,335 $ 26,954 $ 19,435
Summary of Stock Option Activity	A summary of stock option activity for fiscal year 2017 is as follows (in thousands, except per share amounts): Number of Shares Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Term (in Years) Aggregate Intrinsic Value Options outstanding - September 30, 2016 1,048 $ 23.18 Granted (1) 379 44.74 Exercised (234 ) 13.34 Forfeited, canceled or expired (16 ) 56.80 Options outstanding - September 29, 2017 1,177 $ 31.61 4.99 16,445 Options vested and expected to vest - September 29, 2017 1,177 $ 31.61 4.99 16,445 Options exercisable - September 29, 2017 397 $ 23.00 4.16 9,701
Weighted Average Assumptions used for Calculating Fair Value of Stock Options Granted	The weighted average Monte Carlo input assumptions used for calculating the fair value of these market-based stock options are as follows: Fiscal Years 2017 2016 2015 Risk-free interest rate 1.9 % 2.1 % 1.9 % Expected term (years) 7 7 7 Expected volatility 32.3 % 36.5 % 37.4 % The weighted average Black-Scholes input assumptions used for calculating the fair value of these performance-based stock options are as follows: Fiscal Years 2016 2015 Risk-free interest rate 1.15 % 1.2 % Expected term (years) 4 4 Expected volatility 31.8 % 36.2 % Expected dividends — % — %
Summary of Restricted Stock Awards and Unit Activity	A summary of restricted stock awards and units activity for fiscal year 2017 is as follows (in thousands): Number of Shares Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value Issued and unvested - September 30, 2016 1,708 $ 32.76 $ 72,165 Granted (1) 1,276 37.92 Vested (984 ) 26.63 Forfeited, canceled or expired (93 ) 36.30 Issued and unvested shares - September 29, 2017 1,907 39.20 $ 85,093

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Sep. 29, 2017
Discontinued Operations and Disposal Groups [Abstract]
Summary of Operating Results Related to Divested Businesses	The accompanying consolidated statement of operations includes the following operating results related to these divested businesses (in thousands): Fiscal Years 2017 2016 2015 Revenue (1) $ 660 $ — $ 71,712 Cost of revenue (1) 2,252 — 46,931 Gross (loss) profit (1,592 ) — 24,781 Operating expenses: Research and development (1) 29,167 — 2,319 Selling, general and administrative (1) 13,840 — 2,441 Total operating expenses 43,007 — 4,760 (Loss) income from discontinued operations (1) (44,599 ) — 20,021 Other income (2) 7,500 7,500 4,000 Gain on sale (3) 18,022 308 63,321 (Loss) income before income taxes (19,077 ) 7,808 87,342 Income tax provision (benefit) — 2,786 33,211 (Loss) income from discontinued operations (19,077 ) 5,022 54,131 Above includes depreciation & amortization of (2) — — 189 Cash flow from Operating Activities (4) (42,776 ) — (8,522 ) Cash flow from Investing Activities (2) 25,522 7,500 (505 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Sep. 29, 2017
Earnings Per Share [Abstract]
Computation for Basic and Diluted Net Income (Loss) Per Share of Common Stock	The following table set forth the computation for basic and diluted net income (loss) per share of common stock (in thousands, except per share data): Fiscal Years 2017 2016 2015 Numerator: Loss from continuing operations $ (150,416 ) $ (3,588 ) $ (5,542 ) (Loss) income from discontinued operations (19,077 ) 5,022 54,131 Net (loss) income (169,493 ) 1,434 48,589 Net (loss) income attributable to common stockholders $ (169,493 ) $ 1,434 $ 48,589 Denominator: Weighted average common shares outstanding-basic 60,704 53,364 51,146 Weighted average common shares outstanding-diluted 60,704 53,364 51,146 Common stock earnings per share-basic: Continuing operations $ (2.48 ) $ (0.07 ) $ (0.11 ) Discontinued operations (0.31 ) 0.09 1.06 Net common stock earnings per share-basic $ (2.79 ) $ 0.03 $ 0.95 Common stock earnings per share-diluted: Continuing operations $ (2.48 ) $ (0.07 ) $ (0.11 ) Discontinued operations (0.31 ) 0.09 1.06 Net common stock earnings per share-diluted $ (2.79 ) $ 0.03 $ 0.95

Supplemental Cash Flow Inform54

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Sep. 29, 2017
Supplemental Cash Flow Elements [Abstract]
Schedule of Supplemental Cash Flow Information Regarding Noncash Investing and Financing Activities	The following is supplemental cash flow information regarding noncash investing and financing activities (in thousands): Fiscal Years 2017 2016 2015 Cash paid for interest $ 30,529 $ 16,335 $ 15,607 Cash paid (refunded) for income taxes $ (3,161 ) $ (373 ) $ 22,676

Accumulated Other Comprehensi55

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Sep. 29, 2017
Equity [Abstract]
Summary of Accumulated Other Comprehensive Income, Net of Income Taxes	The components of accumulated other comprehensive income (loss), net of income taxes, are as follows: Foreign Currency Items Other Items Total Balance - October 2, 2015 $ (2,182 ) $ (97 ) $ (2,279 ) Foreign currency translation, net of tax 11,320 — 11,320 Unrealized gain/loss on short term investments — (2 ) (2 ) Balance - September 30, 2016 9,138 (99 ) 9,039 Foreign currency translation, net of tax (5,999 ) — (5,999 ) Unrealized gain/loss on short term investments — (63 ) (63 ) Balance at September 29, 2017 $ 3,139 $ (162 ) $ 2,977

Geographic and Significant Cu56

Geographic and Significant Customer Information (Tables)	12 Months Ended
	Sep. 29, 2017
Segment Reporting [Abstract]
Summary of Different Geographic Regions	Information about our operations in different geographic regions, based upon customer locations, is presented below (in thousands): Fiscal Years Revenue by Geographic Region 2017 2016 2015 United States $ 265,038 $ 155,998 $ 152,974 China 206,136 201,911 127,428 Asia Pacific, excluding China (1) 170,826 144,872 103,941 Other Countries (2) 56,772 41,557 36,266 Total $ 698,772 $ 544,338 $ 420,609 (1) Asia Pacific represents Taiwan, Japan, Singapore, India, Thailand, South Korea, Australia, Malaysia, New Zealand, the Philippines and Vietnam. (2) No international country or region represented greater than 10% of the total revenue as of the dates presented, other than China and the Asia-Pacific region as presented above. As of September 29, September 30, Long-Lived Assets by Geographic Region United States $ 101,044 $ 79,832 Asia Pacific (1) 24,945 16,614 Other Countries (2) 5,030 2,721 Total $ 131,019 $ 99,167 (1) Asia Pacific represents Taiwan, Japan, Singapore, India, Thailand, South Korea, Australia, Malaysia, New Zealand, the Philippines, Vietnam and China. (2) No international country or region represented greater than 10% of the total net long-lived assets as of the dates presented, other than the Asia-Pacific region as presented above.
Summary of Customer Concentrations as Percentage of Total Sales and Accounts Receivable	The following is a summary of customer concentrations as a percentage of total sales and accounts receivable as of and for the periods presented: Fiscal Years Revenue 2017 2016 2015 Customer A 11 % 11 % 18 % Customer B 10 % 15 % 8 % Customer C 6 % 12 % 12 % September 29, September 30, Accounts Receivable Customer A 13 % 11 % Customer B 5 % 11 % Customer C 6 % 16 % Customer D 14 % 2 %

Quarterly Financial Data (Una57

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Sep. 29, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Data	(In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Fiscal Year Fiscal Year 2017 Revenue $ 151,752 $ 186,084 $ 194,555 $ 166,381 $ 698,772 Gross profit 78,495 68,864 92,629 86,896 326,884 (Loss) income from continuing operations (2,171 ) (134,267 ) (13,977 ) (1 ) (150,416 ) Income (loss) from discontinued operations (1) 1,206 4,136 (13,700 ) (10,719 ) (19,077 ) Per share data (2) Loss from continuing operations, basic $ (0.04 ) $ (2.21 ) $ (0.22 ) $ (0.00 ) $ (2.48 ) Income (loss) from discontinued operations, basic $ 0.02 $ 0.07 $ (0.21 ) $ (0.17 ) $ (0.31 ) Per share data (2) (3) Loss from continuing operations, diluted $ (0.04 ) $ (2.21 ) $ (0.22 ) $ (0.21 ) $ (2.48 ) Income (loss) from discontinued operations, diluted $ 0.02 $ 0.07 $ (0.21 ) $ (0.16 ) $ (0.31 ) Fiscal Year 2016 Revenue $ 115,774 $ 133,579 $ 142,288 $ 152,697 $ 544,338 Gross profit 60,318 65,525 73,962 81,804 281,609 (Loss) income from continuing operations (16,770 ) (12,045 ) 21,353 3,874 (3,588 ) Income from discontinued operations 1,199 1,396 1,199 1,228 5,022 Per share data (2) (Loss) income from continuing operations, basic $ (0.32 ) $ (0.23 ) $ 0.40 $ 0.07 $ (0.07 ) Income from discontinued operations, basic $ 0.02 $ 0.03 $ 0.02 $ 0.02 $ 0.09 Per share data (2) (3) (Loss) income from continuing operations, diluted $ (0.32 ) $ (0.23 ) $ 0.11 $ 0.07 $ (0.07 ) Income from discontinued operations, diluted $ 0.02 $ 0.03 $ 0.02 $ 0.02 $ 0.09 ____________ (1) During the second quarter of fiscal year 2017, we announced a plan to divest the Compute business of AppliedMicro, and have included the results of the Compute business as discontinued operations in each subsequent quarter. (2) Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding and included common stock equivalents in each period. Therefore, the sums of the quarters do not necessarily equal the full year earnings per share. (3) Diluted income (loss) per share for the fiscal fourth quarter 2017 and fiscal third quarter 2016 excludes $14.0 million and $15.3 million , respectively, related to warrant liability gain

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 30, 2016USD ($)	Sep. 30, 2016USD ($)	Jul. 01, 2016USD ($)	Apr. 01, 2016USD ($)	Jan. 01, 2016USD ($)	Sep. 29, 2017USD ($)segment$ / shares	Sep. 30, 2016USD ($)$ / shares	Oct. 02, 2015USD ($)$ / shares
Description Of Business And Basis Of Presentation [Line Items]
Number of reportable operating segments | segment									1
Change in estimate, rolling average period									12 months
Revenue	$ 166,381	$ 194,555	$ 186,084	$ 151,752	$ 152,697	$ 142,288	$ 133,579	$ 115,774	$ 698,772	$ 544,338	$ 420,609
Net (loss) income									$ (169,493)	$ 1,434	$ 48,589
Earnings per share (in USD per share) | $ / shares									$ (2.79)	$ 0.03	$ 0.95
Reserve related to future rebates and returns	$ 93,500								$ 93,500
Allowance for Rebates and Returns
Description Of Business And Basis Of Presentation [Line Items]
Reserve related to future rebates and returns											$ 6,000
Adjustments Related to Change in Estimate
Description Of Business And Basis Of Presentation [Line Items]
Revenue											17,400
Net (loss) income											$ 7,700
Earnings per share (in USD per share) | $ / shares											$ 0.15
Minimum
Description Of Business And Basis Of Presentation [Line Items]
Definite-lived intangible asset useful life									5 years
Change in estimate as a percent of revenue											10.00%
Maximum
Description Of Business And Basis Of Presentation [Line Items]
Definite-lived intangible asset useful life									14 years
Change in estimate as a percent of revenue											15.00%

Summary of Significant Accoun59

Summary of Significant Accounting policies - Schedule of Estimated Useful Life (Detail)	12 Months Ended
	Sep. 29, 2017
Minimum | Buildings and improvements
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	20 years
Minimum | Machinery and equipment
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	2 years
Minimum | Computer equipment and software
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	2 years
Minimum | Furniture and fixtures
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	7 years
Maximum | Buildings and improvements
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	40 years
Maximum | Machinery and equipment
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	7 years
Maximum | Computer equipment and software
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	5 years
Maximum | Furniture and fixtures
Property Plant And Equipment Estimated Useful Lives [Line Items]
Estimated Useful Life In Years	10 years

Acquisitons - Additional Inform

Acquisitons - Additional Information (Detail) - USD ($)	Aug. 09, 2017	Jul. 31, 2017	May 26, 2017	Jan. 26, 2017	Dec. 14, 2015	Dec. 09, 2015	Dec. 15, 2014	Dec. 30, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Business Acquisition [Line Items]
Equity interests issued and issuable				$ 465,100,000						$ 465,082,000	$ 0	$ 0
Purchase price holdback										1,000,000	0
Goodwill										313,765,000	120,024,000
Contingent consideration										1,679,000	848,000
Aggregate cash consideration										270,008,000	85,517,000	208,352,000
Applied Micro Circuits Corporation
Business Acquisition [Line Items]
Aggregate consideration				695,400,000						695,380,000
Cash paid				287,100,000
Cash acquired from acquisition				56,800,000
Equity interests issued and issuable				465,100,000
Equity interests issued and issuable				453,632,000
Transaction costs										$ 11,900,000
Weighted average life of identified intangible assets acquired										12 years 8 months 12 days
Payments to acquire businesses				287,060,000
Goodwill										$ 183,425,000
Intangible assets										412,848,000
Aggregate cash consideration										230,298,000
Debt assumed										4,444,000
Applied Micro Circuits Corporation | Equity Issuance Costs
Business Acquisition [Line Items]
Transaction costs										1,000,000
Applied Micro Circuits Corporation | Adjustment
Business Acquisition [Line Items]
Aggregate consideration										0
Goodwill										(7,641,000)
Intangible assets										2,500,000
Aggregate cash consideration										0
Debt assumed										0
Picometrix
Business Acquisition [Line Items]
Aggregate consideration	$ 29,500,000
Transaction costs										200,000
Payments to acquire businesses	33,500,000									33,500,000
Indemnification assets	$ 4,000,000
Goodwill										6,183,000
Intangible assets										$ 19,000,000
FiBest Limited
Business Acquisition [Line Items]
Aggregate consideration						$ 59,100,000
Weighted average life of identified intangible assets acquired										9 years 4 months 24 days
Goodwill								$ 15,578,000
Intangible assets								45,650,000
Aggregate cash consideration						47,500,000		47,517,000
Debt assumed						$ 11,600,000		11,627,000
Adjustment to financial liabilities								200,000
FiBest Limited | Selling, general and administrative
Business Acquisition [Line Items]
Transaction costs										$ 0	2,700,000
FiBest Limited | Adjustment
Business Acquisition [Line Items]
Goodwill								220,000
Intangible assets								0
Aggregate cash consideration								0
Debt assumed								0
Aeroflex/Metelics Inc.
Business Acquisition [Line Items]
Weighted average life of identified intangible assets acquired										9 years 10 months 24 days
Goodwill								7,723,000
Intangible assets								20,900,000
Aggregate cash consideration					$ 37,100,000			37,125,000
Aeroflex/Metelics Inc. | Selling, general and administrative
Business Acquisition [Line Items]
Transaction costs										$ 0	$ 500,000
Aeroflex/Metelics Inc. | Adjustment
Business Acquisition [Line Items]
Goodwill								0
Intangible assets								0
Aggregate cash consideration								$ 0
BinOptics Corporation
Business Acquisition [Line Items]
Aggregate consideration							$ 208,400,000
Weighted average life of identified intangible assets acquired										9 years 7 months 6 days
Goodwill									$ 88,369,000
Intangible assets									137,300,000
Aggregate cash consideration									208,352,000
Debt assumed									2,535,000
Additional borrowing under revolving credit facility							100,000,000
Goodwill, tax deductible										$ 0
BinOptics Corporation | Selling, general and administrative
Business Acquisition [Line Items]
Transaction costs												$ 4,200,000
BinOptics Corporation | Retention Escrow Agreement
Business Acquisition [Line Items]
Aggregate consideration							$ 14,600,000
BinOptics Corporation | Adjustment
Business Acquisition [Line Items]
Goodwill									799,000
Intangible assets									400,000
Aggregate cash consideration									0
Debt assumed									$ 0
Antario
Business Acquisition [Line Items]
Aggregate consideration		$ 4,800,000
Payments to acquire businesses		5,800,000
Purchase price holdback		$ 1,000,000
Goodwill										1,600,000
Intangible assets										4,100,000
Triple Play Communications
Business Acquisition [Line Items]
Aggregate consideration			$ 2,200,000
Payments to acquire businesses			2,600,000
Goodwill										3,900,000
Intangible assets										200,000
Contingent consideration			$ 400,000
Employee Stock Options And Restricted Stock | Applied Micro Circuits Corporation
Business Acquisition [Line Items]
Equity interest issued or issuable value assigned				14,500,000
Equity interests issued and issuable				$ 9,300,000						9,307,000
Employee Stock Options And Restricted Stock | Applied Micro Circuits Corporation | Adjustment
Business Acquisition [Line Items]
Equity interests issued and issuable										$ 0

Acquisitions - Schedule of Aggr

Acquisitions - Schedule of Aggregate Purchase Price Allocated to Tangible and Identifiable Intangible Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ / shares in Units, $ in Thousands	Aug. 09, 2017	Jan. 26, 2017	Dec. 14, 2015	Dec. 09, 2015	Dec. 15, 2014	Dec. 30, 2016	Jan. 01, 2016	Mar. 31, 2017	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Consideration:
Cash paid upon closing, net of cash acquired									$ 270,008	$ 85,517	$ 208,352
Goodwill									313,765	120,024
Equity interests issued and issuable		$ 465,100							465,082	0	0
Applied Micro Circuits Corporation
Business Acquisition [Line Items]
Payments to acquire businesses		287,060
Current assets									70,434
Intangible assets									412,848
Assets held for sale									40,944
Other assets									9,800
Total assets acquired									534,026
Liabilities assumed:
Debt									4,444
Other liabilities									17,627
Total liabilities assumed									22,071
Net assets acquired									511,955
Consideration:
Cash paid upon closing, net of cash acquired									230,298
Goodwill									183,425
Equity interests issued and issuable		453,632
Equity consideration for vested in-the-money stock options and unvested restricted stock units		2,143
Fair value of the replacement equity awards attributable to pre-acquisition service		9,307
Total consideration		695,400							695,380
Total consideration paid, less cash acquired		$ 752,142
Equity interest issued (in shares)		9,544,125
Share price (in USD per share)		$ 47.53
Applied Micro Circuits Corporation | Preliminary Allocation as of September 30, 2016
Business Acquisition [Line Items]
Current assets								$ 70,338
Intangible assets								410,348
Assets held for sale								32,458
Other assets								13,504
Total assets acquired								526,648
Liabilities assumed:
Debt								4,444
Other liabilities								17,890
Total liabilities assumed								22,334
Net assets acquired								504,314
Consideration:
Cash paid upon closing, net of cash acquired								230,298
Goodwill								191,066
Total consideration								695,380
Applied Micro Circuits Corporation | Allocation Adjustments
Business Acquisition [Line Items]
Current assets									96
Intangible assets									2,500
Assets held for sale									8,486
Other assets									(3,704)
Total assets acquired									7,378
Liabilities assumed:
Debt									0
Other liabilities									(263)
Total liabilities assumed									(263)
Net assets acquired									7,641
Consideration:
Cash paid upon closing, net of cash acquired									0
Goodwill									(7,641)
Total consideration									0
Aeroflex/Metelics Inc.
Business Acquisition [Line Items]
Current assets						$ 12,614
Intangible assets						20,900
Other assets						3,089
Total assets acquired						36,603
Liabilities assumed:
Other liabilities						7,201
Total liabilities assumed						7,201
Net assets acquired						29,402
Consideration:
Cash paid upon closing, net of cash acquired			$ 37,100			37,125
Goodwill						7,723
Aeroflex/Metelics Inc. | Preliminary Allocation as of September 30, 2016
Business Acquisition [Line Items]
Current assets										12,614
Intangible assets										20,900
Other assets										3,089
Total assets acquired										36,603
Liabilities assumed:
Other liabilities										7,201
Total liabilities assumed										7,201
Net assets acquired										29,402
Consideration:
Cash paid upon closing, net of cash acquired										37,125
Goodwill										7,723
Aeroflex/Metelics Inc. | Allocation Adjustments
Business Acquisition [Line Items]
Current assets						0
Intangible assets						0
Other assets						0
Total assets acquired						0
Liabilities assumed:
Other liabilities						0
Total liabilities assumed						0
Net assets acquired						0
Consideration:
Cash paid upon closing, net of cash acquired						0
Goodwill						0
FiBest Limited
Business Acquisition [Line Items]
Current assets						10,445
Intangible assets						45,650
Other assets						3,317
Total assets acquired						59,412
Liabilities assumed:
Debt				$ 11,600		11,627
Deferred income taxes						11,552
Other liabilities						4,294
Total liabilities assumed						27,473
Net assets acquired						31,939
Consideration:
Cash paid upon closing, net of cash acquired				47,500		47,517
Goodwill						15,578
Total consideration				$ 59,100
FiBest Limited | Preliminary Allocation as of September 30, 2016
Business Acquisition [Line Items]
Current assets										10,445
Intangible assets										45,650
Other assets										3,317
Total assets acquired										59,412
Liabilities assumed:
Debt										11,627
Deferred income taxes										11,658
Other liabilities										3,968
Total liabilities assumed										27,253
Net assets acquired										32,159
Consideration:
Cash paid upon closing, net of cash acquired										47,517
Goodwill										$ 15,358
FiBest Limited | Allocation Adjustments
Business Acquisition [Line Items]
Current assets						0
Intangible assets						0
Other assets						0
Total assets acquired						0
Liabilities assumed:
Debt						0
Deferred income taxes						(106)
Other liabilities						326
Total liabilities assumed						220
Net assets acquired						(220)
Consideration:
Cash paid upon closing, net of cash acquired						0
Goodwill						$ 220
Picometrix
Business Acquisition [Line Items]
Payments to acquire businesses	$ 33,500								33,500
Current assets									7,375
Intangible assets									19,000
Other assets									3,301
Total assets acquired									29,676
Liabilities assumed:
Current liabilities									2,169
Other liabilities									190
Total liabilities assumed									2,359
Net assets acquired									27,317
Consideration:
Goodwill									6,183
Total consideration	$ 29,500
BinOptics Corporation
Business Acquisition [Line Items]
Current assets							$ 22,574
Intangible assets							137,300
Other assets							9,194
Total assets acquired							169,068
Liabilities assumed:
Debt							2,535
Deferred income taxes							33,444
Other liabilities							13,106
Total liabilities assumed							49,085
Net assets acquired							119,983
Consideration:
Cash paid upon closing, net of cash acquired							208,352
Goodwill							88,369
Total consideration					$ 208,400
BinOptics Corporation | Preliminary Allocation as of September 30, 2016
Business Acquisition [Line Items]
Current assets											23,674
Intangible assets											136,900
Other assets											9,194
Total assets acquired											169,768
Liabilities assumed:
Debt											2,535
Deferred income taxes											33,345
Other liabilities											13,106
Total liabilities assumed											48,986
Net assets acquired											120,782
Consideration:
Cash paid upon closing, net of cash acquired											208,352
Goodwill											$ 87,570
BinOptics Corporation | Allocation Adjustments
Business Acquisition [Line Items]
Current assets							(1,100)
Intangible assets							400
Other assets							0
Total assets acquired							(700)
Liabilities assumed:
Debt							0
Deferred income taxes							99
Other liabilities							0
Total liabilities assumed							99
Net assets acquired							(799)
Consideration:
Cash paid upon closing, net of cash acquired							0
Goodwill							$ 799
Common Stock | Applied Micro Circuits Corporation
Consideration:
Equity interests issued and issuable									455,775
Common Stock | Applied Micro Circuits Corporation | Preliminary Allocation as of September 30, 2016
Consideration:
Equity interests issued and issuable								455,775
Common Stock | Applied Micro Circuits Corporation | Allocation Adjustments
Consideration:
Equity interests issued and issuable									0
Employee Stock Options And Restricted Stock | Applied Micro Circuits Corporation
Consideration:
Equity interests issued and issuable		$ 9,300							9,307
Employee Stock Options And Restricted Stock | Applied Micro Circuits Corporation | Preliminary Allocation as of September 30, 2016
Consideration:
Equity interests issued and issuable								$ 9,307
Employee Stock Options And Restricted Stock | Applied Micro Circuits Corporation | Allocation Adjustments
Consideration:
Equity interests issued and issuable									$ 0

Acquisitions - Components of Ac

Acquisitions - Components of Acquired Intangible Assets on a Preliminary Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 436,181	$ 65,350
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	83,518	10,400
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	352,663	$ 54,950
Applied Micro Circuits Corporation
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	412,848
Applied Micro Circuits Corporation | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 78,448
Acquired intangible assets, Useful Lives (Years)	7 years
Applied Micro Circuits Corporation | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 334,400
Acquired intangible assets, Useful Lives (Years)	14 years
FiBest Limited
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 45,650
FiBest Limited | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 9,400
Acquired intangible assets, Useful Lives (Years)	7 years
FiBest Limited | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 36,250
Acquired intangible assets, Useful Lives (Years)	10 years
Aeroflex/Metelics Inc.
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 20,900
Aeroflex/Metelics Inc. | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 1,000
Acquired intangible assets, Useful Lives (Years)	7 years
Aeroflex/Metelics Inc. | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 19,900
Acquired intangible assets, Useful Lives (Years)	10 years
BinOptics Corporation
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 137,300
BinOptics Corporation | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 17,500
Acquired intangible assets, Useful Lives (Years)	7 years
BinOptics Corporation | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 119,800
Acquired intangible assets, Useful Lives (Years)	10 years
Discontinued Operations, Held-for-sale [Member] | Applied Micro Circuits Corporation
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 9,600
Discontinued Operations, Held-for-sale [Member] | Applied Micro Circuits Corporation | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	9,600
Discontinued Operations, Held-for-sale [Member] | Applied Micro Circuits Corporation | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 0

Acquisitions - Summary of Reven

Acquisitions - Summary of Revenue and Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Business Acquisition [Line Items]
(Loss) income from discontinued operations	$ (10,719)	$ (13,700)	$ 4,136	$ 1,206	$ 1,228	$ 1,199	$ 1,396	$ 1,199	$ (19,077)	$ 5,022	$ 54,131
Applied Micro Circuits Corporation
Business Acquisition [Line Items]
Revenue									110,117
Income (loss) before income taxes									(27,222)
(Loss) income from discontinued operations									$ (44,599)
FiBest Limited
Business Acquisition [Line Items]
Revenue										30,540
Income (loss) before income taxes										(4,616)
Aeroflex/Metelics Inc.
Business Acquisition [Line Items]
Revenue										33,552
Income (loss) before income taxes										$ 3,372
BinOptics Corporation
Business Acquisition [Line Items]
Revenue											61,549
Income (loss) before income taxes											$ 354

Acquisitions - Summary of Unaud

Acquisitions - Summary of Unaudited Supplemental Pro Forma Data (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Applied Micro Circuits Corporation
Business Acquisition [Line Items]
Revenue	$ 755,728	$ 707,299
Net (loss) income	(104,828)	(53,613)
Loss from discontinued operations	$ (43,734)	(72,730)
FiBest Limited
Business Acquisition [Line Items]
Revenue		551,964	$ 444,991
Net (loss) income		(3,324)	36,715
Aeroflex/Metelics Inc.
Business Acquisition [Line Items]
Revenue		553,174	459,048
Net (loss) income		$ 1,183	45,107
BinOptics Corporation
Business Acquisition [Line Items]
Revenue			428,440
Net (loss) income			$ (3,489)

Investments - Summary of Availa

Investments - Summary of Available for Sale Investments (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 84,309	$ 23,876
Gross Unrealized Holding Gains	14	10
Gross Unrealized Holding Losses	(202)	(110)
Aggregate Fair Value	84,121	23,776
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,366	14,894
Gross Unrealized Holding Gains	10	9
Gross Unrealized Holding Losses	(166)	(104)
Aggregate Fair Value	26,210	14,799
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	57,943	2,978
Gross Unrealized Holding Gains	4	0
Gross Unrealized Holding Losses	(36)	(3)
Aggregate Fair Value	$ 57,911	2,975
US Government Corporations and Agencies Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		6,004
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses		(3)
Aggregate Fair Value		$ 6,002

Investments - Summary of Contra

Investments - Summary of Contractual Maturities of Investments (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Less than 1 year	$ 60,433
Over 1 year	23,688
Total investments	$ 84,121	$ 23,776

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales of available-for-sale securities	$ 44.6	$ 51.6
Gross realized gains on available-for-sale securities	0	0.1
Gross realized losses on available-for-sale securities	$ 0.1	$ 0.2

Fair Value - Assets and Liabili

Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 84,157	$ 124,901
Total liabilities measured at fair value	42,454	39,101
Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	1,679	848
Common stock warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	40,775	38,253
US treasuries and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		6,002
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	26,210	14,799
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	36	1,172
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	57,911	102,928
Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	36	1,172
Total liabilities measured at fair value	0	0
Active Markets for Identical Assets (Level 1) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Active Markets for Identical Assets (Level 1) | Common stock warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Active Markets for Identical Assets (Level 1) | US treasuries and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		0
Active Markets for Identical Assets (Level 1) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Active Markets for Identical Assets (Level 1) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	36	1,172
Active Markets for Identical Assets (Level 1) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	84,121	123,729
Total liabilities measured at fair value	0	0
Observable Inputs (Level 2) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Observable Inputs (Level 2) | Common stock warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	0	0
Observable Inputs (Level 2) | US treasuries and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		6,002
Observable Inputs (Level 2) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	26,210	14,799
Observable Inputs (Level 2) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Observable Inputs (Level 2) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	57,911	102,928
Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Total liabilities measured at fair value	42,454	39,101
Unobservable Inputs (Level 3) | Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	1,679	848
Unobservable Inputs (Level 3) | Common stock warrant liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	40,775	38,253
Unobservable Inputs (Level 3) | US treasuries and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		0
Unobservable Inputs (Level 3) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Unobservable Inputs (Level 3) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Unobservable Inputs (Level 3) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 0	$ 0

Fair Value - Quantitative Infor

Fair Value - Quantitative Information Used in Fair Value Calculation of Level 3 Liabilities (Details) - $ / shares	Dec. 28, 2016	Sep. 29, 2017	Sep. 30, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	8.50%
Unobservable Inputs (Level 3) | Discounted cash flow | Fair Value, Measurements, Recurring | Contingent consideration
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate		9.20%	12.90%
Expected term			1 year
Unobservable Inputs (Level 3) | Discounted cash flow | Fair Value, Measurements, Recurring | Contingent consideration | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of achievement		70.00%
Expected term		2 months
Unobservable Inputs (Level 3) | Discounted cash flow | Fair Value, Measurements, Recurring | Contingent consideration | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probability of achievement		100.00%
Expected term		8 months
Unobservable Inputs (Level 3) | Black-scholes model | Fair Value, Measurements, Recurring | Common stock warrant liability
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate		1.62%	1.14%
Expected term		3 years 2 months 23 days	4 years 2 months 23 days
Volatility		44.90%	43.20%
Exercise price (in USD per share)		$ 14.05	$ 14.05
Share price (in USD per share)		$ 44.61	$ 42.34
Dividend rate		0.00%	0.00%

Fair Value - Changes in Assets

Fair Value - Changes in Assets and Liabilities with Inputs Classified within Level 3 of Fair Value (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Contingent consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 848	$ 1,150	$ 820
Net Realized/Unrealized Losses (Gains) Included in Earnings	180	98	(330)
Purchases and Issuances	1,701	0	0
Sales and Settlements	(1,050)	(400)	0
Transfers in and/or (out) of Level 3	0	0	0
Ending balance	1,679	848	1,150
Warrant liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	38,253	21,822	15,802
Net Realized/Unrealized Losses (Gains) Included in Earnings	2,522	16,431	(6,020)
Purchases and Issuances	0	0	0
Sales and Settlements	0	0	0
Transfers in and/or (out) of Level 3	0	0	0
Ending balance	$ 40,775	38,253	21,822
Trading securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		$ 0	250
Net Realized/Unrealized Losses (Gains) Included in Earnings			0
Purchases and Issuances			500
Sales and Settlements			(750)
Transfers in and/or (out) of Level 3			0
Ending balance			$ 0

Accounts Receivables Allowanc71

Accounts Receivables Allowances- Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance - beginning of year	$ 3,279	$ 5,745	$ 725
Provision, net	29,512	10,453	11,010
Charge-offs	(23,381)	(12,919)	(5,990)
Balance - end of year	9,410	3,279	5,745
Compensation Credits and Customer Returns Allowance
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance - beginning of year	3,000	5,500
Balance - end of year	8,900	3,000	5,500
Allowance for Doubtful Accounts
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance - beginning of year	200	200
Balance - end of year	$ 300	$ 200	$ 200

Inventories - Components of Inv

Inventories - Components of Inventories (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 78,999	$ 67,378
Work-in-process	13,962	9,157
Finished goods	43,113	38,400
Total	$ 136,074	$ 114,935

Property Plant and Equipment -

Property Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 235,986	$ 178,201
Less accumulated depreciation and amortization	(104,967)	(79,034)
Property and equipment — net	131,019	99,167
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	0	12,572
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	22,195	9,415
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	160,955	126,432
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	13,809	12,152
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	2,078	1,469
Capital lease assets
Property, Plant and Equipment [Line Items]
Total property and equipment	20,410	3,207
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 16,539	$ 12,954

Property Plant and Equipment 74

Property Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 27,300	$ 20,400	$ 15,700
Property, Plant and Equipment [Line Items]
Total property and equipment	235,986	178,201
Capital lease assets
Property, Plant and Equipment [Line Items]
Total property and equipment	20,410	$ 3,207
Corporate Facility Leases | Capital lease assets
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 16,900

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	May 19, 2017	Mar. 10, 2017	Sep. 29, 2017	Mar. 09, 2017	Dec. 30, 2016	Aug. 31, 2016	Jan. 01, 2016	Dec. 09, 2015	Feb. 28, 2015	May 08, 2014
Debt Instrument [Line Items]
Write off of deferred debt issuance cost	$ 1,100,000	$ 900,000
Deferred financing costs, net			$ 13,700,000
FiBest Limited
Debt Instrument [Line Items]
Debt assumed					$ 11,627,000			$ 11,600,000
BinOptics Corporation
Debt Instrument [Line Items]
Debt assumed							$ 2,535,000
Term Loans
Debt Instrument [Line Items]
Line of credit effective interest rate			3.50%
Borrowings outstanding			$ 680,906,000
Quarterly principal installments			$ 1,700,000
Maximum period for reinvestment of business divestiture proceeds			18 months
Maximum period for completion of reinvestment of business divestiture proceeds			6 months
Deferred financing costs, net			$ 12,500,000
Principal balance			686,741,000
Estimated fair value of term loans			$ 696,200,000
Term Loans | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate			2.25%
Term Loans | One Month LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Term Loans | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate			0.50%
Term Loans | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate			1.25%
Term Loans | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Deferred financing costs, net			$ 1,200,000
Credit Agreement
Debt Instrument [Line Items]
Deferred financing costs										$ 8,700,000
Credit Agreement | Term Loans
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 350,000,000
Discount rate	0.50%									0.75%
Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		160,000,000	160,000,000						$ 130,000,000	$ 100,000,000
Line of credit facility increase (decrease)		30,000,000
Borrowings outstanding		0	$ 0
Maximum letters of credit outstanding		$ 5,000,000
Maximum letters of credit outstanding as a percentage of borrowings outstanding		35.00%		25.00%
Term Loans
Debt Instrument [Line Items]
Principal balance	$ 588,500,000
Term Loans | Second Incremental Term Loan Amendment
Debt Instrument [Line Items]
Debt instrument face amount	100,000,000
Incremental Term Loan Amendment
Debt Instrument [Line Items]
Deferred financing costs						$ 3,200,000
Incremental Term Loan Amendment | Term Loans
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 250,000,000
Discount rate						0.95%
March 2017 Amendments
Debt Instrument [Line Items]
Deferred financing costs		$ 1,000,000
May 2017 Amendments
Debt Instrument [Line Items]
Deferred financing costs	$ 11,100,000

Debt - Schedule of Remained Out

Debt - Schedule of Remained Outstanding on Term Loans (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Debt Instrument [Line Items]
Current portion	$ 6,885	$ 6,051
Long-term, less current portion	661,471	$ 573,882
Term Loans
Debt Instrument [Line Items]
Principal balance	686,741
Unamortized discount	(5,835)
Total term loans	680,906
Current portion	6,885
Long-term, less current portion	$ 674,021

Debt - Schedule of Minimum Prin

Debt - Schedule of Minimum Principal Payments under Term Loans (Detail) - Term Loans $ in Thousands	Sep. 29, 2017USD ($)
Debt Instrument [Line Items]
2,018	$ 6,885
2,019	6,885
2,020	6,885
2,021	6,885
2,022	6,885
Thereafter	652,316
Total	$ 686,741

Capital Lease and Financing O78

Capital Lease and Financing Obligations (Details) - USD ($) $ in Millions	Dec. 28, 2016	Sep. 29, 2017
Capital Leased Assets [Line Items]
Discount rate	8.50%
100 Chelmsford Street
Capital Leased Assets [Line Items]
Lease Term	20 years
Financing obligations associated with leased facility	$ 8.2
Proceeds from corporate facility financing	4.2
Construction allowances	$ 4
144 Chelmsford Street Lease
Capital Leased Assets [Line Items]
Lease Term	20 years
Capital lease obligations incurred		$ 3.6
121 Hale Street
Capital Leased Assets [Line Items]
Lease Term	14 years
Financing obligations associated with leased facility	$ 4
Corporate Facility Leases
Capital Leased Assets [Line Items]
Lease Term	20 years
Financing obligations associated with leased facility		15.8
FiBest and Bin Optics
Capital Leased Assets [Line Items]
Financing obligations associated with leased facility		$ 2.3

Capital Lease and Financing O79

Capital Lease and Financing Obligations Future Minimum Lease Payments (Details) $ in Thousands	Sep. 29, 2017USD ($)
Capital Lease and Financing Obligations [Abstract]
2,018	$ 1,895
2,019	1,791
2,020	1,619
2,021	1,485
2,022	1,276
Thereafter	19,264
Total minimum capital lease payments	27,330
Less amount representing interest	(14,698)
Present value of net minimum capital lease payments	$ 12,632

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Foreign Jurisdictions
Employee Benefit Plan [Line Items]
Discretionary matching contribution	$ 1,300,000	$ 1,100,000	$ 1,000,000
Calender Year 2015 | US
Employee Benefit Plan [Line Items]
Discretionary matching contribution	2,400,000
Calender Year 2016 | US
Employee Benefit Plan [Line Items]
Discretionary matching contribution	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Lease Payments for Operating Leases (Detail) $ in Thousands	Sep. 29, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 11,116
2,019	9,001
2,020	5,985
2,021	3,828
2,022	3,113
Thereafter	7,999
Total minimum lease payments	$ 41,042

Commitments and Contingencies82

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Sep. 29, 2017	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Loss Contingencies [Line Items]
Rent expenses		$ 10.9	$ 7	$ 6.5
Asset retirement obligation	$ 2.3	2.3	$ 4.3	$ 1.3
Outstanding non-cancelable purchase commitments	1.8
Letter of Credit
Loss Contingencies [Line Items]
Outstanding unused letters of credit	$ 0.4	$ 0.4

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Other Liabilities Disclosure [Abstract]
Compensation and benefits	$ 32,505	$ 32,563
Distribution costs	5,777	3,584
Income taxes payable	4,184	0
Product warranty	3,672	1,039
Professional fees	2,140	1,706
Deferred revenue	1,994	340
Contingent consideration	1,679	848
Rent and utilities	1,257	1,310
Purchase price holdback	1,000	0
Asset retirement obligations	959	2,932
Restructuring costs	627	3,104
Interest payable	532	4,314
Other	3,911	2,628
Total	$ 60,237	$ 54,368

Restructurings - Summary of Cos

Restructurings - Summary of Costs Related to Restructuring Actions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 3,104	$ 943	$ 801
Current period charges	2,744	3,465	1,280
Payments	(5,221)	(1,304)	(1,138)
Ending balance	$ 627	$ 3,104	$ 943

Restructurings- Additional Deta

Restructurings- Additional Details (Details) $ in Millions	Sep. 29, 2017USD ($)
Minimum
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring costs	$ 3.6
Maximum
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring costs	$ 4.5

Product Warranties - Additional

Product Warranties - Additional Information (Detail)	12 Months Ended
	Sep. 29, 2017
Guarantees [Abstract]
Term of product warranties	12 months

Product Warranties - Schedule o

Product Warranties - Schedule of Product Warranty Liability Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance — beginning of year	$ 1,039	$ 656	$ 446
Acquired	952	413	50
Provisions	1,737	(30)	160
Direct charges	(56)	0	0
Balance — end of year	$ 3,672	$ 1,039	$ 656

Intangible Assets - Summary of

Intangible Assets - Summary of Amortization Expense of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Finite-Lived Intangible Assets [Line Items]
Total	$ 65,742	$ 50,255	$ 38,980
Cost of revenue
Finite-Lived Intangible Assets [Line Items]
Total	30,286	26,615	27,285
Selling, general and administrative
Finite-Lived Intangible Assets [Line Items]
Total	$ 35,456	$ 23,640	$ 11,695

Intangible Assets - Summary o89

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Total	$ 811,703	$ 384,471
Less accumulated amortization	(190,611)	(124,869)
Intangible assets — net	621,092	259,602
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Total	0	8,000
Trade name
Finite-Lived Intangible Assets [Line Items]
Total	3,400	3,400
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Total	251,655	165,397
Less accumulated amortization	(106,800)	(76,700)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Total	556,648	207,674
Less accumulated amortization	$ (83,900)	$ (48,100)

Intangible Assets - Summary o90

Intangible Assets - Summary of Activity in Intangible Assets and Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 29, 2017	Sep. 29, 2017	Sep. 30, 2016
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		$ 384,471	$ 318,006
Acquired		436,181	65,350
Placed in service		0
Fair value adjustment		0	1,678
Currency translation adjustments		(4,597)	8,857
Impairments of intangible assets		(4,352)	(10,088)
Other intangibles purchased			668
Ending balance	$ 811,703	811,703	384,471
In-process research and development
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		8,000	8,000
Acquired		0	0
Placed in service		(3,648)
Fair value adjustment		0	0
Currency translation adjustments		0	0
Impairments of intangible assets	(4,352)		0
Other intangibles purchased			0
Ending balance	0	0	8,000
Trade name
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		3,400	3,400
Acquired		0	0
Placed in service		0
Fair value adjustment		0	0
Currency translation adjustments		0	0
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	3,400	3,400	3,400
Goodwill
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		120,024	93,346
Acquired		195,145	20,412
Placed in service		0
Fair value adjustment		220	3,475
Currency translation adjustments		(1,624)	2,791
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	313,765	313,765	120,024
Acquired technology
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		165,397	162,536
Acquired		83,518	10,400
Placed in service	3,648
Fair value adjustment		0	78
Currency translation adjustments		(908)	1,803
Impairments of intangible assets		0	(10,088)
Other intangibles purchased			668
Ending balance	251,655	251,655	165,397
Customer relationships
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		207,674	144,070
Acquired		352,663	54,950
Placed in service		0
Fair value adjustment		0	1,600
Currency translation adjustments		(3,689)	7,054
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	$ 556,648	$ 556,648	$ 207,674

Intangible Assets - Summary o91

Intangible Assets - Summary of Estimated Amortization of Intangible Assets (Detail) $ in Thousands	Sep. 29, 2017USD ($)
Amortization expense
2,018	$ 82,798
2,019	90,429
2,020	88,030
2,021	79,161
2,022	65,468
Thereafter	$ 211,806

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 29, 2017	Jul. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Finite-Lived Intangible Assets [Line Items]
Impairments of intangible assets			$ (4,352)	$ (10,088)
Placed in service			0
Accumulated amortization	$ 190,611		190,611	124,869
Impairment charges		$ 13,800	4,352	12,955	$ 3,500
Impairment charges			4,352	11,765	$ 0
Inventory impairment charges		2,000
Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Impairment charges		10,100
Fixed Assets
Finite-Lived Intangible Assets [Line Items]
Impairment charges		600
Contractual Commitments
Finite-Lived Intangible Assets [Line Items]
Impairment charges		$ 1,100
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Impairments of intangible assets			0	(10,088)
Placed in service	3,648
Accumulated amortization	106,800		106,800	76,700
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Impairments of intangible assets			0	0
Placed in service			0
Accumulated amortization	83,900		83,900	48,100
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Impairments of intangible assets	$ (4,352)			$ 0
Placed in service			$ (3,648)

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Sep. 30, 2016
Deferred tax assets (liabilities):
Federal and foreign net operating losses and credits	$ 396,871	$ 85,256
Intangible assets	(180,544)	(49,725)
Property and equipment	(1,045)	(2,730)
Other non-current deferred tax assets	20,756	21,855
Discontinued operations	0	9,100
Deferred compensation	9,291	5,545
Deferred gain	14,853	19,011
Valuation allowance	(274,406)	(10,471)
Total deferred tax (liability) asset	$ (14,224)	$ 77,841

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Income Taxes [Line Items]
Income tax expense (benefit)	$ 100,911	$ (17,983)	$ (9,858)
Reserve related to future rebates and returns	93,500
Valuation allowance change	140,419	(994)	1,965
Income (loss) from operations before income taxes	$ (49,505)	$ (21,571)	$ (15,400)
Effective income tax rate	(203.80%)	83.40%	63.90%
Undistributed earnings	$ 158,600
Unrecognized tax benefits	300
Out of Period Adjustment
Income Taxes [Line Items]
Income tax expense (benefit)	3,900
Japan
Income Taxes [Line Items]
Deferred tax liability	8,800
United States
Income Taxes [Line Items]
Valuation allowance change	263,900
Ireland
Income Taxes [Line Items]
Undistributed earnings	58,300
Grand Cayman
Income Taxes [Line Items]
Undistributed earnings	90,100
Federal
Income Taxes [Line Items]
Operating loss carryforwards	1,084,800
Applied Micro Circuits Corporation
Income Taxes [Line Items]
Valuation allowance amount	274,400
Applied Micro Circuits Corporation | Federal
Income Taxes [Line Items]
Operating loss carryforwards	772,700
Mindspeed Wireless Business | Federal
Income Taxes [Line Items]
Operating loss carryforwards	158,900
BinOptics Corporation | Federal
Income Taxes [Line Items]
Operating loss carryforwards	26,200
Mindspeed Acquisition
Income Taxes [Line Items]
Valuation allowance amount		$ 10,500
Tax Year 2015 | Out of Period Adjustment
Income Taxes [Line Items]
Income tax expense (benefit)	1,700
Tax Year 2014 | Out of Period Adjustment
Income Taxes [Line Items]
Income tax expense (benefit)	1,000
Tax Year 2013 | Out of Period Adjustment
Income Taxes [Line Items]
Income tax expense (benefit)	1,200
MACOM | Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 127,000

Income Taxes - Summary of Domes

Income Taxes - Summary of Domestic and Foreign Income (Loss) from Continuing Operations Before Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Income Tax Disclosure [Abstract]
United States	$ (111,432)	$ (46,593)	$ (34,251)
Foreign	61,927	25,022	18,851
(Loss) income from operations before income taxes	$ (49,505)	$ (21,571)	$ (15,400)

Income Taxes - Components of Pr

Income Taxes - Components of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Current:
Federal	$ 100	$ (5,861)	$ (19,015)
State	225	(766)	688
Foreign	7,307	906	1,092
Current provision (benefit)	7,632	(5,721)	(17,235)
Deferred:
Federal	(42,637)	(8,163)	10,845
State	(4,037)	(502)	(4,131)
Foreign	(466)	(2,603)	(1,302)
Change in valuation allowance	140,419	(994)	1,965
Deferred provision (benefit)	93,279	(12,262)	7,377
Total provision (benefit)	$ 100,911	$ (17,983)	$ (9,858)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rates (Detail)	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Income Tax Disclosure [Abstract]
Federal statutory rate	35.00%	35.00%	35.00%
Foreign rate differential	31.90%	40.10%	30.50%
State taxes net of federal benefit	0.20%	1.00%	3.50%
Warrant liabilities	(1.80%)	(26.70%)	(13.70%)
Change in valuation allowance	(270.00%)	3.00%	(6.00%)
Research and development credits	12.80%	16.90%	16.10%
Correction of prior period	0.00%	18.30%	0.00%
Provision to return adjustments	(4.00%)	3.50%	9.90%
Nondeductible compensation expense	(4.10%)	(9.20%)	(8.90%)
Nondeductible legal fees	(3.90%)	(1.80%)	(4.10%)
Other permanent differences	0.10%	3.30%	1.60%
Effective income tax rate	(203.80%)	83.40%	63.90%

Income Taxes - Activity Related

Income Taxes - Activity Related to Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Beginning balance	$ (1,670)	$ (1,670)
Additions based on tax positions	0	0
Reductions based on tax positions	0	0
Ending balance	$ (1,670)	$ (1,670)

Share-Based Compensation Plans

Share-Based Compensation Plans - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended			24 Months Ended
	Jan. 31, 2017USD ($)$ / sharesshares	Nov. 30, 2016USD ($)$ / sharesshares	Sep. 29, 2017USD ($)trancheplan$ / sharesshares	Sep. 30, 2016USD ($)$ / sharesshares	Oct. 02, 2015USD ($)$ / sharesshares	Sep. 30, 2016USD ($)$ / sharesshares	Jul. 26, 2017$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans | plan			3
Number of shares available for future issuance (in shares)			13,000,000
Compensation and benefits | $			$ 32,505	$ 32,563		$ 32,563
Share-based compensation expense | $			36,335	26,954	$ 19,435
Unrecognized compensation costs | $			$ 62,100
Weighted average period for recognition of unrecognized compensation costs			2 years 6 months
Options granted (in shares)			379,000
Intrinsic value of options recognized | $			$ 8,900	$ 3,700	7,100
Exercise price of options (in USD per share) | $ / shares			$ 44.74
Number of shares (in shares)			1,177,000
Common stock, issued (in shares)			64,279,000	53,709,000		53,709,000
Incentive Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
ISU awards outstanding (in shares)			203,000
Compensation and benefits | $			$ 4,400
Share-based compensation expense | $			$ 3,900	$ 4,000	$ 1,800
Stock Options with Performance-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term						7 years
Options granted (in shares)						230,000
Options, aggregate grant date fair value | $						$ 2,400
Exercise price of options (in USD per share) | $ / shares						$ 34.22
Number of shares (in shares)			50,000
Total fair value of restricted stock awards and units vesting | $			$ 7,100
Stock Options with Market-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term	7 years	7 years		7 years
Weighted average period for recognition of unrecognized compensation costs	3 years	3 years		3 years	3 years
Options granted (in shares)	10,000	310,000		300,000	30,000
Options, aggregate grant date fair value | $	$ 200	$ 4,100		$ 3,500	$ 400
Grant date fair value of options (in USD per share) | $ / shares					$ 12.38
Exercise price of options (in USD per share) | $ / shares					29.80
Target price per share of common stock for recognition of unrecognized compensation cost (in USD per share) | $ / shares	$ 80.7	$ 66.96		$ 64.22
Trailing average period for target price per share of common stock for recognition of unrecognized compensation cost			30 days
Target price per share of common stock at which options become subject to vesting (in USD per share) | $ / shares					$ 63.60
Number of consecutive trading days			3 days
Share price (in USD per share) | $ / shares							$ 63.60
Restricted Stock Awards and Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			1,276,000
Total fair value of restricted stock awards and units vesting | $			$ 51,200	$ 26,500	$ 23,300
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of vesting restricted stock units | $			$ 79,300
PRSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			69,109
Number of tranches | tranche			3
Instruments other than options vested and expected to vest outstanding (in shares)			203,011
Employee Stock | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum ESPP payroll deductions			15.00%
Common stock, issued (in shares)			146,149	154,187	175,900	154,187
Maximum percentage annual increase of share available for future issuance			1.25%
Annual increase of share available for future issuance (in shares)			550,000
Employee Stock | 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage annual increase of share available for future issuance			4.00%
Annual increase of share available for future issuance (in shares)			1,900,000
Compute Business
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $			$ 800
Automotive Divestiture
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $					$ 400
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term			7 years
Minimum | Stock Options with Performance-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of options (in USD per share) | $ / shares						$ 10.12
Minimum | PRSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Instruments other than options vested and expected to vest outstanding (in shares)			75,349
Minimum | PRSU awards | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			0.00%
Minimum | PRSU awards | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			0.00%
Minimum | PRSU awards | Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term			10 years
Maximum | Stock Options with Performance-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of options (in USD per share) | $ / shares						$ 10.54
Maximum | PRSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			300.00%
Incremental PRSU that could vest if all performance criteria are achieved			442,605
Maximum | PRSU awards | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			300.00%
Maximum | PRSU awards | Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earnings percentage of targeted shares			300.00%
Maximum | Employee Stock | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of share available for future issuance (in shares)			550,000
Maximum | Employee Stock | 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of share available for future issuance (in shares)			1,900,000
Applied Micro Circuits Corporation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)			59,107
Applied Micro Circuits Corporation | Restricted Stock Awards and Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			306,089

Share-Based Compensation Pla100

Share-Based Compensation Plans - Effects of Stock-Based Compensation Expense Related to Stock-Based Awards to Employees and Non-Employees (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 36,335	$ 26,954	$ 19,435
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3,189	2,150	1,949
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	10,565	6,568	5,447
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 22,581	$ 18,236	$ 12,039

Share-Based Compensation Pla101

Share-Based Compensation Plans - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 29, 2017USD ($)$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	1,048
Granted (in shares) | shares	379
Exercised (in shares) | shares	(234)
Forfeited, canceled or expired (in shares) | shares	(16)
Ending balance (in shares) | shares	1,177
Weighted-Average Exercise Price per Share
Beginning balance (in USD per share) | $ / shares	$ 23.18
Granted (in USD per share) | $ / shares	44.74
Exercised (in USD per share) | $ / shares	13.34
Forfeited, canceled or expired (in USD per share) | $ / shares	56.80
Ending balance (in USD per share) | $ / shares	$ 31.61
Options Outstanding, Additional Disclosures
Aggregate Intrinsic Value | $	$ 16,445
Weighted-Average Remaining Contractual Term (in Years)	4 years 11 months 26 days
Options Vested and Expected to Vest
Number of shares (in shares) | shares	1,177
Weighted-Average Exercise Price Per Share (in USD per share) | $ / shares	$ 31.61
Weighted-Average Remaining Contractual Term (in Years)	4 years 11 months 26 days
Aggregate Intrinsic Value | $	$ 16,445
Options Exercisable
Number of Shares (in shares) | shares	397
Weighted-Average Exercise Price per Share (in USD per share) | $ / shares	$ 23
Weighted-Average Remaining Contractual Term (in Years)	4 years 1 month 27 days
Aggregate Intrinsic Value | $	$ 9,701

Share-Based Compensation Pla102

Share-Based Compensation Plans - Weighted Average Assumptions used for Calculating Fair Value of Stock Options Granted (Detail)	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Stock Options with Market-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.90%	2.10%	1.90%
Expected term (years)	7 years	7 years	7 years
Expected volatility	32.30%	36.50%	37.40%
Stock Options with Performance-based Vesting Criteria
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate		1.15%	1.20%
Expected term (years)		4 years	4 years
Expected volatility		31.80%	36.20%
Expected dividends		0.00%	0.00%

Share-Based Compensation Pla103

Share-Based Compensation Plans - Summary of Restricted Stock Awards and Units Activity (Detail) - Restricted Stock Awards and Units - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016
Number of Shares
Beginning balance- unvested (in shares)	1,708
Granted (in shares)	1,276
Vested (in shares)	(984)
Forfeited, canceled or expired (in shares)	(93)
Ending balance- unvested (in shares)	1,907
Weighted-Average Grant Date Fair Value
Beginning balance- unvested (in USD per share)	$ 32.76
Granted (in USD per share)	37.92
Vested (in USD per share)	26.63
Forfeited, canceled or expired (in USD per share)	36.30
Ending balance- unvested (in USD per share)	$ 39.20
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 85,093	$ 72,165

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	Sep. 29, 2017	Sep. 30, 2016	Mar. 31, 2012
Class of Warrant or Right [Line Items]
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	300,000,000	300,000,000
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, subject to forfeiture (in shares)	200	3,300
Common stock warrants price per share (in USD per share)			$ 14.05
Common Stock
Class of Warrant or Right [Line Items]
Common stock warrants (in shares)			1,281,358

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Gaas Labs Llc
Related Party Transaction [Line Items]
Minimum service requirements or payment obligations	$ 0
Notice period to terminate agreement	30 days
Revenue from product and service sales to related parties	$ 0	$ 0	$ 0
Public Company with a Common Director
Related Party Transaction [Line Items]
Revenue from product and service sales to related parties			$ 1,100,000
Cadence | Public Company with a Common Director
Related Party Transaction [Line Items]
Expenses from transactions with related party	6,300,000
Public Company with a Common Director
Related Party Transaction [Line Items]
Revenue from product and service sales to related parties	$ 0	$ 0

Discontinued Operations - Addit

Discontinued Operations - Additional information (Detail) - USD ($)	Sep. 29, 2017	Aug. 17, 2015	Sep. 30, 2015	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015	Oct. 03, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 35,571,000			$ 35,571,000	$ 0
Inventory and other current assets	1,300,000			1,300,000
Property and equipment	7,800,000			7,800,000
Goodwill and intangible assets	28,400,000			28,400,000
Provision for disposal costs	2,000,000			2,000,000
Liabilities held for sale	$ 2,144,000			2,144,000	0
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other income				7,500,000	7,500,000	$ 4,000,000
Gain on sale				18,022,000	$ 308,000	63,321,000
Discontinued Operations, Disposed of by Sale | Automotive Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration on sale of business		$ 82,100,000
Cash consideration on sale of business, amounts payable from counterparty		$ 18,000,000
Cash consideration on sale of business, period for cash payables due		18 months
Gain on sale				$ 18,000,000		61,800,000
Discontinued Operations, Disposed of by Sale | Automotive Business | Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Additional cash proceeds to be received from revenue-based earnout		$ 30,000,000
Discontinued Operations, Disposed of by Sale | Consulting Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-design advisory services period		2 years
Discontinued Operations, Disposed of by Sale | Consulting Agreement | Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration on sale of business		$ 15,000,000
Discontinued Operations, Disposed of by Sale | Mindspeed Wireless Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of assets							$ 12,300,000
Gain on sale			$ 1,600,000			$ 1,600,000
Compute Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected disposal period	12 months

Discontinued Operations - Summa

Discontinued Operations - Summary of Operating Results Through Dates of Divestiture Related to Divested Businesses (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Operating expenses:
(Loss) income from discontinued operations		$ (10,719)	$ (13,700)	$ 4,136	$ 1,206	$ 1,228	$ 1,199	$ 1,396	$ 1,199	$ (19,077)	$ 5,022	$ 54,131
Cash flow from Investing Activities (2)										25,520	7,500	81,208
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue (1)										660	0	71,712
Cost of revenue (1)										2,252	0	46,931
Gross (loss) profit										(1,592)	0	24,781
Operating expenses:
Research and development (1)										29,167	0	2,319
Selling, general and administrative (1)										13,840	0	2,441
Total operating expenses										43,007	0	4,760
(Loss) income from discontinued operations (1)										(44,599)	0	20,021
Other income (2)										7,500	7,500	4,000
Gain on sale (3)										18,022	308	63,321
(Loss) income before income taxes										(19,077)	7,808	87,342
Income tax provision (benefit)										0	2,786	33,211
(Loss) income from discontinued operations										(19,077)	5,022	54,131
Above includes depreciation & amortization of (2)										0	0	189
Cash flow from Operating Activities (4)										(42,776)	0	(8,522)
Cash flow from Investing Activities (2)										25,522	$ 7,500	(505)
Discontinued Operations, Disposed of by Sale | Automotive Business
Operating expenses:
Gain on sale (3)										$ 18,000		61,800
Discontinued Operations, Disposed of by Sale | Mindspeed Wireless Business
Operating expenses:
Gain on sale (3)	$ 1,600											$ 1,600

Earnings Per Share - Computatio

Earnings Per Share - Computation for Basic and Diluted Net Income (Loss) Per Share of Common Stock (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Numerator:
Loss from continuing operations	$ (1)	$ (13,977)	$ (134,267)	$ (2,171)	$ 3,874	$ 21,353	$ (12,045)	$ (16,770)	$ (150,416)	$ (3,588)	$ (5,542)
(Loss) income from discontinued operations	$ (10,719)	$ (13,700)	$ 4,136	$ 1,206	$ 1,228	$ 1,199	$ 1,396	$ 1,199	(19,077)	5,022	54,131
Net (loss) income									(169,493)	1,434	48,589
Net (loss) income attributable to common stockholders									$ (169,493)	$ 1,434	$ 48,589
Denominator:
Weighted average common shares outstanding-basic (in shares)									60,704	53,364	51,146
Weighted average common shares outstanding-diluted (in shares)									60,704	53,364	51,146
Basic (loss) income per share:
Continuing operations (in USD per share)	$ 0	$ (0.22)	$ (2.21)	$ (0.04)	$ 0.07	$ 0.40	$ (0.23)	$ (0.32)	$ (2.48)	$ (0.07)	$ (0.11)
Discontinued operations (in USD per share)									(0.31)	0.09	1.06
(Loss) income per share-basic (in USD per share)									(2.79)	0.03	0.95
Diluted (loss) income per share:
Continuing operations (in USD per share)	$ (0.21)	$ (0.22)	$ (2.21)	$ (0.04)	$ 0.07	$ 0.11	$ (0.23)	$ (0.32)	(2.48)	(0.07)	(0.11)
Discontinued operations (in USD per share)									(0.31)	0.09	1.06
(Loss) income per share-diluted (in USD per share)									$ (2.79)	$ 0.03	$ 0.95

Earnings Per Share - Common Equ

Earnings Per Share - Common Equivalent Shares Excluded from Calculation from Net Income Per Share (Detail) - shares	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded from earnings per share (in shares)	1,877,401	1,855,049	2,055,779

Supplemental Cash Flow Infor110

Supplemental Cash Flow Information - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 26, 2017	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Business Acquisition [Line Items]
Unpaid amounts related to purchase of assets		$ 7,600	$ 800
Equity interests issued and issuable	$ 465,100	465,082	$ 0	$ 0
Fixed assets acquired		$ 3,600

Supplemental Cash Flow Infor111

Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information Regarding Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 30,529	$ 16,335	$ 15,607
Cash paid (refunded) for income taxes	$ (3,161)	$ (373)	$ 22,676

Accumulated Other Comprehens112

Accumulated Other Comprehensive Income (Loss) - Summary of Accumulated Other Comprehensive Income, Net of Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 462,784	$ 424,533
Ending balance	777,374	462,784
Foreign currency translation, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	9,138	(2,182)
Other comprehensive income	(5,999)	11,320
Ending balance	3,139	9,138
Other Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(99)	(97)
Ending balance	(162)	(99)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	9,039	(2,279)
Ending balance	2,977	9,039
Unrealized gain/loss on short term investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income	$ (63)	$ (2)

Geographic and Significant C113

Geographic and Significant Customer Information - Summary of Different Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Segment Reporting Information [Line Items]
Revenue	$ 166,381	$ 194,555	$ 186,084	$ 151,752	$ 152,697	$ 142,288	$ 133,579	$ 115,774	$ 698,772	$ 544,338	$ 420,609
Long-lived assets	131,019				99,167				131,019	99,167
United States
Segment Reporting Information [Line Items]
Revenue									265,038	155,998	152,974
Long-lived assets	101,044				79,832				101,044	79,832
China
Segment Reporting Information [Line Items]
Revenue									206,136	201,911	127,428
Asia Pacific, excluding China
Segment Reporting Information [Line Items]
Revenue									170,826	144,872	103,941
Long-lived assets	24,945				16,614				24,945	16,614
Other Countries
Segment Reporting Information [Line Items]
Revenue									56,772	41,557	$ 36,266
Long-lived assets	$ 5,030				$ 2,721				$ 5,030	$ 2,721

Geographic and Significant C114

Geographic and Significant Customer Information - Summary of Customer Concentrations as Percentage of Total Sales and Accounts Receivable (Detail) - Customer Concentration Risk	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Total Sales
Segment Reporting Information [Line Items]
Concentration risk, percentage	52.00%	62.00%	57.00%
Total Sales | Customer A
Segment Reporting Information [Line Items]
Concentration risk, percentage	11.00%	11.00%	18.00%
Total Sales | Customer B
Segment Reporting Information [Line Items]
Concentration risk, percentage	10.00%	15.00%	8.00%
Total Sales | Customer C
Segment Reporting Information [Line Items]
Concentration risk, percentage	6.00%	12.00%	12.00%
Accounts Receivable | Customer A
Segment Reporting Information [Line Items]
Concentration risk, percentage	13.00%	11.00%
Accounts Receivable | Customer B
Segment Reporting Information [Line Items]
Concentration risk, percentage	5.00%	11.00%
Accounts Receivable | Customer C
Segment Reporting Information [Line Items]
Concentration risk, percentage	6.00%	16.00%
Accounts Receivable | Customer D
Segment Reporting Information [Line Items]
Concentration risk, percentage	14.00%	2.00%

Geographic and Significant C115

Geographic and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Sep. 29, 2017segmentcustomer	Sep. 30, 2016customer	Oct. 02, 2015customer
Segment Reporting Information [Line Items]
Number of reportable operating segments | segment	1
Total Revenue | Customer Concentration Risk
Segment Reporting Information [Line Items]
Number of major customers | customer	10	10	10
Concentration risk, percentage	52.00%	62.00%	57.00%

Quarterly Financial Data - Sche

Quarterly Financial Data - Schedule of Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 166,381	$ 194,555	$ 186,084	$ 151,752	$ 152,697	$ 142,288	$ 133,579	$ 115,774	$ 698,772	$ 544,338	$ 420,609
Gross profit	86,896	92,629	68,864	78,495	81,804	73,962	65,525	60,318	326,884	281,609	203,590
Loss from continuing operations	(1)	(13,977)	(134,267)	(2,171)	3,874	21,353	(12,045)	(16,770)	(150,416)	(3,588)	(5,542)
(Loss) income from discontinued operations	$ (10,719)	$ (13,700)	$ 4,136	$ 1,206	$ 1,228	$ 1,199	$ 1,396	$ 1,199	$ (19,077)	$ 5,022	$ 54,131
Per share data
Income (loss) from continuing operations (in USD per share)	$ 0	$ (0.22)	$ (2.21)	$ (0.04)	$ 0.07	$ 0.40	$ (0.23)	$ (0.32)	$ (2.48)	$ (0.07)	$ (0.11)
Income (loss) from discontinued operations (in USD per share)	(0.17)	(0.21)	0.07	0.02	0.02	0.02	0.03	0.02	(0.31)	0.09	1.06
Per share data
Income (loss) from continuing operations (in USD per share)	(0.21)	(0.22)	(2.21)	(0.04)	0.07	0.11	(0.23)	(0.32)	(2.48)	(0.07)	(0.11)
Income (loss) from discontinued operations (in USD per share)	$ (0.16)	$ (0.21)	$ 0.07	$ 0.02	$ 0.02	$ 0.02	$ 0.03	$ 0.02	$ (0.31)	$ 0.09	$ 1.06
Warrant liability gain	$ 14,000					$ 15,300

Subsequent Events- Narrative (D

Subsequent Events- Narrative (Details) - Compute Business - Subsequent Event $ in Millions	Oct. 27, 2017USD ($)
Subsequent Event [Line Items]
Consideration on sale of business	$ 36.5
Equity interest in Buyer	20.00%