Semtech (SMTC) 10-Q 30 May 18 2019 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Apr. 29, 2018	May 25, 2018
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Apr. 29, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,019
Document Fiscal Period Focus	Q1
Entity Registrant Name	SEMTECH CORP
Entity Central Index Key	88,941
Current Fiscal Year End Date	--01-27
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,184,781

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Net sales	$ 130,429	$ 143,802
Cost of sales	58,960	58,887
Gross profit	71,469	84,915
Operating costs and expenses:
Selling, general and administrative	41,406	34,015
Product development and engineering	26,199	25,983
Intangible amortization	6,961	6,286
Loss on disposition of business operations	0	375
Total operating costs and expenses	74,566	66,659
Operating (loss) income	(3,097)	18,256
Interest expense, net	(2,190)	(2,046)
Non-operating income (expense), net	190	(632)
(Loss) income before taxes and equity in net losses of equity method investments	(5,097)	15,578
Provision for taxes	(17,510)	3,757
Net income before equity in net losses of equity method investments	12,413	11,821
Equity in net losses of equity method investments	(31)	0
Net income	$ 12,382	$ 11,821
Earnings per share:
Basic (in dollars per share)	$ 0.19	$ 0.18
Diluted (in dollars per share)	$ 0.18	$ 0.18
Weighted average number of shares used in computing earnings per share:
Basic (in shares)	66,324	65,839
Diluted (in shares)	68,195	67,376

Condensed Consolidated Stateme3

Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Net income	$ 12,382	$ 11,821
Other comprehensive income, net:
Unrealized gain on convertible debt	0	750
Change in employee benefit plans	(16)	21
Other comprehensive income, net	31	901
Comprehensive income	12,413	12,722
Foreign Exchange Contract [Member]
Other comprehensive income, net:
Unrealized (loss) gain	47	183
Realized gain on foreign currency cash flow hedges	$ 0	$ (53)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Current assets:
Cash and cash equivalents	$ 303,349	$ 307,923
Accounts receivable, less allowances of $2,710 and $9,089, respectively	65,568	53,183
Inventories	65,458	71,067
Prepaid taxes	12,874	11,809
Other current assets	20,143	17,250
Total current assets	467,392	461,232
Non-current assets:
Property, plant and equipment, net of accumulated depreciation of $184,686 and $179,604, respectively	122,469	124,586
Deferred tax assets	24,907	4,236
Goodwill	341,897	341,897
Other intangible assets, net	53,246	60,207
Other assets	88,894	93,618
TOTAL ASSETS	1,098,805	1,085,776
Current liabilities:
Accounts payable	38,676	37,208
Accrued liabilities	54,400	60,832
Deferred revenue	4,973	12,758
Current portion - long-term debt	16,358	15,410
Total current liabilities	114,407	126,208
Non-current liabilities:
Deferred tax liabilities	15,812	14,682
Long term debt, less current portion	206,552	211,114
Other long-term liabilities	68,680	68,759
Commitments and contingencies (Note 11)
Stockholders’ equity:
Common stock, $0.01 par value, 250,000,000 shares authorized, 78,136,144 issued and 66,140,592 outstanding and 78,136,144 issued and 66,280,129 outstanding, respectively	785	785
Treasury stock, at cost, 11,995,552 shares and 11,856,015 shares, respectively	(268,864)	(251,974)
Additional paid-in capital	438,364	415,056
Retained earnings	524,238	502,346
Accumulated other comprehensive loss	(1,169)	(1,200)
Total stockholders’ equity	693,354	665,013
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 1,098,805	$ 1,085,776

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts, receivables	$ 2,710	$ 9,089
Accumulated depreciation	$ 184,686	$ 179,604
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	78,136,144	78,136,144
Common stock, shares outstanding	66,140,592	66,280,129
Treasury stock, shares	11,995,552	11,856,015

Condensed Consolidated Stateme6

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Cash flows from operating activities:
Net income	$ 12,382	$ 11,821
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	12,453	11,301
Accretion of deferred financing costs and debt discount	136	146
Deferred income taxes	(15,614)	3,151
Share-based compensation and warrant costs	35,516	13,286
(Gain) loss on disposition of business operations and assets	(10)	436
Equity in net losses of equity method investments	31	0
Contingencies	0	(50)
Corporate owned life insurance, net	(254)	248
Changes in assets and liabilities:
Accounts receivable, net	(7,844)	(4,471)
Inventories	5,609	(11,292)
Other assets	(1,098)	3,265
Accounts payable	3,203	(4,147)
Accrued liabilities	(6,852)	(12,536)
Deferred revenue	(180)	299
Income taxes payable	(1,698)	(3,222)
Other liabilities	(751)	2,124
Net cash provided by operating activities	35,029	10,359
Cash flows from investing activities:
Proceeds from sales of property, plant and equipment	27	6
Purchase of property, plant and equipment	(4,935)	(5,175)
Purchase of investments	(5,490)	(4,750)
Proceeds from sale of investments	1,601	0
Net cash used in investing activities	(8,797)	(9,919)
Cash flows from financing activities:
Payments of term loans	(3,750)	(3,750)
Payment for employee share-based compensation payroll taxes	(5,769)	(3,467)
Proceeds from exercise of stock options	4,038	1,159
Repurchase of outstanding common stock	(25,325)	(9,966)
Net cash used in financing activities	(30,806)	(16,024)
Net decrease in cash and cash equivalents	(4,574)	(15,584)
Cash and cash equivalents at beginning of period	307,923	297,134
Cash and cash equivalents at end of period	303,349	281,550
Supplemental disclosure of cash flow information
Income taxes paid	648	1,869
Interest paid	1,929	1,809
Non-cash items
Capital expenditures in accounts payable	2,054	1,511
Convertible debt	$ 0	$ 2,175

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Apr. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Nature of Business Semtech Corporation (together with its consolidated subsidiaries, the "Company" or "Semtech") is a global supplier of analog and mixed-signal semiconductor products. The end customers for the Company’s products are primarily original equipment manufacturers ("OEMs") that produce and sell electronics. The Company designs, develops and markets a wide range of products for commercial applications, the majority of which are sold into the enterprise computing, communications, high-end consumer and industrial end-markets. Enterprise Computing: datacenters, passive optical networks, desktops, notebooks, servers, monitors, printers and other computer peripherals. Communications: base stations, optical networks, carrier networks, switches and routers, cable modems, wireless LAN and other communication infrastructure equipment. High-End Consumer: handheld products, smartphones, wireless charging, set-top boxes, digital televisions, tablets, digital video recorders and other consumer equipment. Industrial: video broadcast equipment, Video-over-IP solutions, automated meter reading, Internet of Things ("IoT"), smart grid, wireless charging, military and aerospace, medical, security systems, automotive, industrial and home automation and other industrial equipment. Fiscal Year The Company reports results on the basis of 52 and 53 week periods and ends its fiscal year on the last Sunday in January. The other quarters generally end on the last Sunday of April, July and October. All quarters consist of 13 weeks except for one 14 -week period in the fourth quarter of 53 -week years. The first quarter of fiscal years 2019 and 2018 each consisted of 13 weeks. Principles of Consolidation The accompanying interim unaudited consolidated financial statements have been prepared by the Company, in accordance with accounting principles generally accepted in the United States ("GAAP") and on the same basis as the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended January 28, 2018 . In the opinion of the Company, these interim unaudited consolidated financial statements contain all adjustments (consisting of normal recurring adjustments) necessary to present fairly, in all material respects, the financial position of the Company for the interim periods presented. All intercompany balances have been eliminated. Certain information and footnote disclosures normally included in annual consolidated financial statements have been condensed or omitted pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Because the interim unaudited consolidated financial statements do not include all of the information and notes required by GAAP for a complete set of consolidated financial statements, they should be read in conjunction with the audited consolidated financial statements and notes included in the Company's Annual Report on Form 10-K for the year ended January 28, 2018. The results reported in these interim unaudited consolidated financial statements should not be regarded as indicative of results that may be expected for any subsequent period or for the entire year. The Company’s interim unaudited consolidated statements of income are referred to herein as the "Statements of Income." The Company’s interim unaudited consolidated balance sheets are referred to herein as the "Balance Sheets" and interim unaudited consolidated statements of cash flows as the "Statements of Cash Flows." Segment Information The Company’s Chief Executive Officer ("CEO") has been identified as the Chief Operating Decision Maker ("CODM") as defined by guidance regarding segment disclosures (see Note 13 for further discussion). Prior to the first quarter of fiscal year 2019, the Company had four operating segments. However as of April 29, 2018 , the Company identified three operating segments that aggregate into one reportable segment, the Semiconductor Products Group. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Recent Accounting Standards Adopted In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers (Accounting Standards Codification ("ASC") 606), which requires an entity to recognize revenue from the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance addresses, in particular, contracts with more than one performance obligation, as well as the accounting for some costs to obtain or fulfill a contract with a customer, and provides for additional disclosures with respect to revenues and cash flows arising from contracts with customers. The Company adopted the standard, effective January 29, 2018, using the modified retrospective transition method which resulted in an adjustment to retained earnings for the cumulative effect of applying the standard to all contracts not completed as of the adoption date. The primary change associated with the adoption relates to the Company’s sales to distributors with return or price adjustment rights where the Company will no longer defer revenue until the resale by the distributor to the end customer, but rather, will record revenue at the time control transfers to the distributor. The Company estimated the effects of returns and allowances provided to these distributors. Upon adoption, including the effect of income taxes, opening retained earnings as of January 29, 2018 increased by $11.1 million net, as a result of these changes. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Asset Transfers Other Than Inventory (Topic 740). This accounting standard update is aimed at recognizing the income tax consequences of intra-entity transfers of assets other than inventory when they occur. This removes the exception to postpone the recognition of income tax consequences of intra-entity transfers until the asset has been sold to an outside party. In the first quarter of 2019, the Company adopted ASU 2016-16 using a modified retrospective transition method, resulting in a $1.8 million decrease in retained earnings, a $3.7 million net increase in deferred income tax assets, and a $5.5 million decrease in pre-paid taxes. Accounting Guidance Issued but Not Adopted as of April 29, 2018 In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815). This standard addresses narrow issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity. Part I addresses the complexity of accounting for certain financial instruments with down round features. Part II addresses the difficulty of navigating Topic 480, Distinguishing Liabilities from Equity, because of the existence of pending content in the ASC that results from the indefinite deferral of accounting requirements concerning mandatorily redeemable financial instruments of certain non-public entities and certain mandatorily redeemable non-controlling interests. The new standard is effective for interim and annual fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company does not expect the adoption of this pronouncement to have a material impact on the Company’s consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815). The new standard is designed to refine and expand hedge accounting for both financial (e.g., interest rate) and commodity risks. Its provisions create more transparency around how economic results are presented, both on the face of the financial statements and in the footnotes. It also makes certain targeted improvements to simplify the application of hedge accounting guidance. The new standard is effective for interim and annual fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption, including adoption in an interim period, is permitted. The Company is currently evaluating the impact this ASU will have on its consolidated condensed financial statements and disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which will require that substantially all leases be recognized by lessees on their balance sheets as a right-of-use asset and corresponding lease liability, including leases currently accounted for as operating leases. The new standard also will result in enhanced quantitative and qualitative disclosures, including descriptions of significant judgments made by management, to provide greater insight into the extent of expense recognized and expected to be recognized from existing leases. The standard requires modified retrospective adoption and will be effective for the Company as of the beginning of fiscal year 2020. The Company expects the valuation of right of use assets and lease liabilities, previously described as operating leases, to be the present value of the Company's forecasted future lease commitments. The Company is continuing to assess the overall impacts of the new standard, including the discount rate to be applied in these valuations.

Revenue

Revenue	3 Months Ended
	Apr. 29, 2018
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The Company derives its revenue primarily from the sale of semiconductor products into various end markets. Revenue is recognized when control of these products is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for these products. Control is generally transferred when products are shipped and, to a lesser extent, when the products are delivered. Recovery of costs associated with product design and engineering services are recognized during the period in which services are performed and are reported as a reduction to product development and engineering expense. Historically, these recoveries have not exceeded the cost of the related development efforts. The Company includes revenue related to granted technology licenses as part of "Net sales." Historically, revenue from these arrangements has not been significant though it is part of its recurring ordinary business. The Company determines revenue recognition through the following five steps: • Identification of the contract, or contracts, with a customer • Identification of the performance obligations in the contract • Determination of the transaction price • Allocation of the transaction price to the performance obligations in the contract • Recognition of revenue when, or as, performance obligations are satisfied The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. The Company’s revenue contracts generally represent a single performance obligation to sell its products to trade customers. Net sales reflect the transaction prices for contracts, which include units shipped at selling prices reduced by variable consideration. Determination of variable consideration requires judgment by the Company. Variable consideration includes expected sales returns and other price adjustments. Variable consideration is estimated using the expected value method considering all reasonably available information, including the Company’s historical experience and its current expectations, and is reflected in the transaction price when sales are recorded. Sales returns are generally accepted at the Company’s discretion or from distributors with such rights. The Company’s contracts with trade customers do not have significant financing components or non-cash consideration. The Company records net sales excluding taxes collected on its sales to its trade customers. The Company provides an assurance type warranty which is typically not sold separately and does not represent a separate performance obligation. The Company’s payment terms are generally aligned with shipping terms. The following presents the amounts by which financial statement line items were affected in the current period due to the adoption of ASC 606 as compared with the guidance that was in effect before the change: Three Months Ended Statements of Income April 29, 2018 (in thousands, except per share amounts) Increase/(decrease) Net sales $ 4,462 Cost of sales 1,016 Provision for taxes 724 Net income 2,722 Earnings per share: Basic $ 0.04 Diluted $ 0.04 Balance Sheets April 29, 2018 (in thousands) Increase/(decrease) Deferred revenue $ (15,737 ) Excludes line items that were not materially affected by the Company's adoption of ASC 606. The adoption had no impact to total net cash provided by or used in operating, investing or financing activities in the Statements of Cash Flows. Contract Modifications: If a contract is modified, which does not normally occur, changes in contract specifications and requirements must be accounted for. The Company considers contract modifications to exist when the modification either creates new or changes the existing enforceable rights and obligations. Most of the Company’s contract modifications are to distributor agreements for adding new goods or services that are considered distinct from the existing contract and the change in contract price reflects the standalone selling price of the distinct service. Disaggregated Revenue: The Company disaggregates revenue from contracts with customers by types of products and geography, as it believes it best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Refer to “Note 13 : Segment Information” for further information on revenues by product line and geographic region. Contract Balances: Accounts receivable represents the Company’s unconditional right to receive consideration from its customer. Contract assets consist of the Company’s right to consideration in exchange for goods or services that the Company has transferred to a customer when that right is conditioned on something other than the passage of time. ASC 606 also requires an entity to present a revenue contract as a contract liability in instances when a customer pays consideration, or an entity has a right to an amount of consideration that is unconditional (e.g. receivable), before the entity transfers a good or service to the customer. The opening and closing contract asset and contract liability balances are not material. There were no impairment losses recognized on the Company’s accounts receivable and contract assets during the three months ended April 29, 2018. There were no significant changes in the contract assets and the contract liabilities during the three months ended April 29, 2018. Practical Expedients: Unsatisfied Performance Obligations: Because all of the Company’s performance obligations relate to contracts with a duration of less than one year, the Company elected to apply the optional exemption provided in ASC 606 and, therefore, is not required to disclose the aggregate amount of the transaction price allocated to performance obligations that are unsatisfied or partially unsatisfied at the end of the reporting period. Contract Costs: All incremental customer contract acquisition costs are expensed as they are incurred as the amortization period of the asset that the Company otherwise would have recognized is one year or less in duration. Significant Financing Component: The Company does not adjust the promised amount of consideration for the effects of a significant financing component as the Company expects, at contract inception, that the period between when the Company transfers a promised good or service to a customer and when the customer pays for that good or service will be one year or less. Sales Tax Exclusion from the Transaction Price: The Company excludes from the measurement of the transaction price all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from the customer. Shipping and Handling Activities: The Company accounts for shipping and handling activities performed after a customer obtains control of the good as activities to fulfill the promise to transfer the good.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Apr. 29, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share The computation of basic and diluted earnings per common share was as follows: Three Months Ended (in thousands, except per share amounts) April 29, 2018 April 30, 2017 Net income $ 12,382 $ 11,821 Weighted average common shares outstanding - basic 66,324 65,839 Dilutive effect of stock options and restricted stock units 1,871 1,537 Weighted average common shares outstanding - diluted 68,195 67,376 Basic earnings per common share $ 0.19 $ 0.18 Diluted earnings per common share $ 0.18 $ 0.18 Anti-dilutive shares not included in the above calculations 146 686 Basic earnings per common share is computed by dividing income available to common stockholders by the weighted-average number of shares of common stock outstanding during the reporting period. Diluted earnings per common share incorporates the incremental shares issuable, calculated using the treasury stock method, upon the assumed exercise of non-qualified stock options, the vesting of restricted stock units and performance unit awards if the conditions have been met.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Apr. 29, 2018
Share-based Compensation [Abstract]
Share-Based Compensation	Share-Based Compensation Financial Statement Effects and Presentation . The following table summarizes pre-tax share-based compensation included in the Statements of Income for the three months ended April 29, 2018 and April 30, 2017 . Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Revenue offset $ 21,501 $ 5,280 Cost of sales 328 564 Selling, general and administrative 11,462 5,557 Product development and engineering 2,225 1,885 Share-based compensation $ 35,516 $ 13,286 Net change in share-based compensation capitalized into inventory $ — $ (414 ) Warrant . On October 5, 2016, the Company issued a warrant (the "Warrant") to Comcast Cable Communications Management LLC ("Comcast") to purchase up to 1,086,957 shares (the "Warrant Shares") of the common stock of Semtech Corporation. The Warrant was issued by the Company to Comcast in connection with an agreement between the parties regarding the intended trial deployment by Comcast of a low-power wide-area Network ("LPWAN") in the United States, based on the Company’s LoRa® devices and wireless radio frequency technology. The Warrant is accounted for as equity and the cost is recognized as an offset to net sales over the respective performance period. The Warrant consists of five performance tranches. The cost associated with each tranche has been recognized based on the fair value at each reporting date until vesting which is the measurement date. On April 27, 2018, the Company accelerated the vesting of the remaining 586,956 unvested shares from the Warrant, resulting in the full recognition of the remaining costs to be recognized for the Warrant. For the three -month period ended April 29, 2018 , the revenue offset reflects the cost associated with the Warrant of $21.5 million , including $15.9 million related to the acceleration. The Warrant is now fully-vested and exercisable for a total of 869,565 shares, with no additional costs to be recognized in future periods. Performance-Based Restricted Stock Units . The Company grants performance-based restricted stock units to select employees. The performance-based restricted stock units are valued as of the measurement date and expense is recognized on a straight line basis for the awards expected to vest based on the probability of attainment of the performance condition for each separately vesting portion of the award. In the first quarter of fiscal year 2019 , the Company granted 200,442 performance-based restricted stock units that have a pre-defined market condition and a service condition that are accounted for as equity awards. The market condition is determined based upon the Company’s total stockholder return ("TSR") benchmarked against the TSR of the S&P SPDR Semiconductor ETF (NYSE:XSD) over a one , two and three year period ( one-third of the awards vesting each performance period ). The fiscal year 2019 award recipients must be employed for the entire performance period and be an active employee at the time of vesting of the awards. The Company used a Monte Carlo simulation to determine the grant-date fair value for these awards, which takes into consideration the possible outcomes pertaining to the TSR market condition. The grant-date fair value per unit of the awards granted in the first quarter of fiscal year 2019 for each one, two and three year performance period is $33.02 , $34.85 and $36.52 , respectively. Award Modifications . During the first quarter of fiscal year 2019, the Company modified the terms of 159,000 fully vested shares held by 8 employees. As a result of the modification, additional compensation cost of $2.8 million was recognized during the first quarter of fiscal year 2019.

Investments

Investments	3 Months Ended
	Apr. 29, 2018
Investments [Abstract]
Investments	Investments Cash and cash equivalents includes investments in money market funds that are valued based on the net asset value of the funds. The cash equivalents consist primarily of money market funds that are Level 1 measurements. The investments in these funds were $ 30.0 million and $0.0 million as of April 29, 2018 and January 28, 2018 , respectively. The following table summarizes the Company’s available-for-sale securities: April 29, 2018 January 28, 2018 (in thousands) Market Value Adjusted Cost Gross Unrealized Gain Market Value Adjusted Cost Gross Unrealized Gain Convertible debt $ 2,500 $ 2,500 $ — $ 1,960 $ 1,960 $ — Total other assets $ 2,500 $ 2,500 $ — $ 1,960 $ 1,960 $ — The following table summarizes the maturities of the Company’s available-for-sale securities: April 29, 2018 January 28, 2018 (in thousands) Market Value Adjusted Cost Market Value Adjusted Cost Within 1 year $ 2,000 $ 2,000 $ 1,960 $ 1,960 After 1 year through 5 years 500 500 — — Total investments $ 2,500 $ 2,500 $ 1,960 $ 1,960 The Company's available-for-sales securities consisted of investments in convertible debt instruments issued by privately-held companies and is included in "Other current assets" within the Balance Sheets. The Company currently has a $30.0 million investment, which includes $3.0 million of restricted deposits, in a private entity that is accounted for at cost and included in "Other assets" within the Balance Sheets. As part of its investment, the Company received a call option that allows the Company to purchase all of the outstanding equity of the entity. The call option, which was out-of-the-money at inception, is exercisable until June 30, 2018.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Apr. 29, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Instruments Measured at Fair Value on a Recurring Basis Financial assets and liabilities measured and recorded at fair value on a recurring basis were presented within the Company's Balance Sheets as follows: Fair Value as of April 29, 2018 Fair Value as of January 28, 2018 (in thousands) Total (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Financial assets: Cash equivalents $ 30,000 $ 30,000 $ — $ — $ — $ — $ — $ — Derivative financial instruments 64 — 64 — — — — — Convertible debt 2,500 — — 2,500 1,960 — — 1,960 Total financial assets $ 32,564 $ 30,000 $ 64 $ 2,500 $ 1,960 $ — $ — $ 1,960 Financial liabilities: AptoVision Earn-out $ 21,000 $ — $ — $ 21,000 $ 21,000 $ — $ — $ 21,000 Cycleo Earn-out 668 — — 668 668 — — 668 Total financial liabilities $ 21,668 $ — $ — $ 21,668 $ 21,668 $ — $ — $ 21,668 During the three months ended April 29, 2018 , the Company had no transfers of financial assets or liabilities between Level 1, Level 2 or Level 3. As of April 29, 2018 and January 28, 2018 , the Company had not elected the fair value option for any financial assets and liabilities for which such an election would have been permitted. The fair values of the foreign exchange forward contracts are valued using Level 2 inputs. Foreign currency forward contracts are valued using readily available foreign currency forward and interest rate curves. The fair value of each contract is determined by comparing the contract rate to the forward rate and discounting to the present value. Contracts in a gain position are recorded in the Balance Sheets within the caption "Other current assets" and the value of contracts in a loss position are recorded within the caption "Accrued liabilities" within the Balance Sheets. Please see Note 16 for further discussion of the Company’s derivative instruments. The convertible debt is valued using probability weighted cash flows (Level 3 inputs). The AptoVision Earn-out liability is valued utilizing estimates of annual revenue, adjusted earnings and product development targets (Level 3 inputs) through July 2020. These estimates represent inputs for which market data are not available and are developed using the best information available about the assumptions that market participants would use when pricing the liability. The Cycleo Earn-out liability (see Note 11 ) is valued utilizing estimates of annual revenue and operating income (Level 3 inputs) through April 2020. These estimates represent inputs for which market data are not available and are developed using the best information available about the assumptions that market participants would use when pricing the liability. The Company measures contingent earn-out liabilities at fair value on a recurring basis using significant unobservable inputs classified within Level 3 of the fair value hierarchy. The Company uses a Monte Carlo valuation method as a valuation technique to determine the value of the earn-out liability. The significant unobservable inputs used in the fair value measurements are revenue projections over the earn-out period, and the probability outcome percentages assigned to each scenario. Significant increases or decreases to either of these inputs in isolation would result in a significantly higher or lower liability, with a higher liability capped by the contractual maximum of the contingent earn-out obligation. Ultimately, the liabilities will be equivalent to the amount paid, and the difference between the fair value estimate and amount paid will be recorded in earnings. For the Cycleo Earn-out and AptoVision Earn-out, these companies have business profiles comparable to a start-up company. Accordingly, their respective revenue projections are subject to significant revisions. This characteristic can result in volatile changes to the measurement of fair value for a given earn-out. The Company reviews and re-assesses the estimated fair value of contingent consideration on a recurring basis, and the updated fair value could differ materially from the previous estimates. Changes in the estimated fair value of the Company’s contingent earn-out liabilities related to the time component of the present value calculation are reported in "Interest expense" within the Statements of Income. Adjustments to the estimated fair value related to changes in all other unobservable inputs are reported in operating income. A reconciliation of the change in the earn-out liability during the three months ended April 29, 2018 is as follows: (in thousands) AptoVision Cycleo Total Balance at January 28, 2018 $ 21,000 $ 668 $ 21,668 Changes in the fair value of contingent earn-out obligations — — — Current acquisitions — — — Payments — — — Balance as of April 29, 2018 $ 21,000 $ 668 $ 21,668 Instruments Not Recorded at Fair Value on a Recurring Basis Some of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate fair value due to their liquid or short-term nature. Such financial assets and financial liabilities include: cash and cash equivalents, net receivables, certain other assets, accounts payable, accrued expenses, accrued personnel costs, and other current liabilities. The Company’s long-term debt is not recorded at fair value on a recurring basis, but is measured at fair value for disclosure purposes. The fair value of the Company’s Term Loans (as defined in Note 9 ) is $127.5 million and $131.3 million as of April 29, 2018 and January 28, 2018 , respectively. The fair value of the Company's Revolving Commitments (as defined in Note 9 ) is $97.0 million as of both April 29, 2018 and January 28, 2018 , respectively. These are based on Level 2 inputs which are derived from transactions with similar amounts, maturities, credit ratings and payment terms. Assets and Liabilities Recorded at Fair Value on a Non-Recurring Basis The Company reduces the carrying amounts of its goodwill, intangible assets, long-lived assets and non-marketable equity securities to fair value when held for sale or determined to be impaired. For its investment in non-marketable equity interests, the Company has not identified events or changes in circumstances that may have a significant adverse effect on the fair value of its equity investments during the first three months of fiscal year 2019 .

Inventories

Inventories	3 Months Ended
	Apr. 29, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories, consisting of material, material overhead, labor, and manufacturing overhead, are stated at the lower of cost (first-in, first-out) or market and consist of the following: (in thousands) April 29, 2018 January 28, 2018 Raw materials $ 1,583 $ 1,651 Work in progress 42,078 46,884 Finished goods 21,797 22,532 Inventories $ 65,458 $ 71,067

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Apr. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill – Changes in the carrying amount of goodwill by applicable reporting unit were as follows: (in thousands) Signal Integrity Wireless and Sensing Total Balance at January 28, 2018 $ 274,085 $ 67,812 $ 341,897 Additions — — — Balance at April 29, 2018 $ 274,085 $ 67,812 $ 341,897 As a result of the realignment of its operating segments, during the first quarter of fiscal year 2019, the Company combined the Wireless and Sensing and the Power and High-Reliability reporting units (see Note 13). Goodwill of $49.4 million related to the Power and High-Reliability reporting unit which was previously a separate reporting unit is now included in the Wireless and Sensing reporting unit’s goodwill balance. The reporting units are the same as the operating segments which are part of a single reportable segment. The difference between the fair value and the carrying amount of these reporting units is one of several factors the Company will consider before reaching its conclusion about whether to perform the first step of the goodwill impairment test. Purchased Intangibles – The following table sets forth the Company’s finite-lived intangible assets resulting from business acquisitions, which continue to be amortized: April 29, 2018 January 28, 2018 (in thousands) Estimated Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core technologies 5-8 years $ 164,930 $ (121,156 ) $ 43,774 $ 164,930 $ (115,628 ) $ 49,302 Customer relationships 3-10 years 34,031 (26,859 ) 7,172 34,031 (25,426 ) 8,605 Total finite-lived intangible assets $ 198,961 $ (148,015 ) $ 50,946 $ 198,961 $ (141,054 ) $ 57,907 Amortization expenses recorded in the Statements of Income for each period were as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Core technologies $ 5,528 $ 5,186 Customer relationships 1,433 1,100 Total amortization expense $ 6,961 $ 6,286 The following table sets forth the Company’s indefinite-lived intangible assets resulting from additions to IPR&D: (in thousands) Net Carrying Value Value at January 28, 2018 $ 2,300 In-process research and development through acquisitions — Value at April 29, 2018 $ 2,300 The Company reviews indefinite-lived intangible assets for impairment as of November 30, each year, by comparing the carrying amount of the asset to the future discounted cash flows that asset is expected to generate.

Credit Facilities

Credit Facilities	3 Months Ended
	Apr. 29, 2018
Debt Instruments [Abstract]
Credit Facilities	Credit Facilities On November 15, 2016 (the "Closing Date"), Semtech Corporation, with certain of its domestic subsidiaries as guarantors (the "Guarantors"), entered into the amended and restated credit facility with the lenders party thereto ("Lenders"), and HSBC Bank USA, National Association, as administrative agent and as swing line lender and letter of credit issuer (the "Credit Agreement"). The Credit Agreement amended and restated the Company's prior credit agreement. The Company accounted for the Credit Agreement as a debt modification. Pursuant to the Credit Agreement, the Lenders provided the Company with senior secured first lien credit facilities in an aggregate principal amount of $400.0 million , consisting of term loans in an aggregate initial principal amount of $150.0 million (the "Term Loans") and revolving credit commitments in an aggregate principal amount of $250.0 million (the "Revolving Commitments"). Up to $40.0 million of the Revolving Commitments may be used to obtain letters of credit, up to $25.0 million of the Revolving Commitments may be used to obtain swing line loans, and up to $40.0 million of the Revolving Commitments may be used to obtain revolving loans and letters of credit in certain currencies other than U.S. Dollars. Each of the Term Loans and the Revolving Commitments is scheduled to mature on November 12, 2021 . As of April 29, 2018 , there were no amounts outstanding under the letters of credit, swing line loans and alternative currency sub facilities. All of the proceeds of the Credit Agreement were used to repay in full all of the obligations outstanding under the Company’s prior credit facility and to pay transaction costs in connection with such refinancing. As of November 15, 2016, $247.0 million of borrowings were outstanding under the Credit Agreement, consisting of $150.0 million in term loans and $97.0 million in revolving loans, and there was $153.0 million of undrawn revolving commitments. The proceeds of the revolving credit facility may be used by the Company for capital expenditures, permitted acquisitions, permitted dividends, working capital and general corporate purposes. The Credit Agreement provides that, subject to certain conditions, the Company may request the establishment of one or more additional term loan facilities and/or increases to the Revolving Commitments in an aggregate principal amount not to exceed the sum of (a) $150.0 million and (b) the aggregate principal amount of all voluntary prepayments of term loans made prior to the date of incurrence of such additional term loan facilities and/or increases to the revolving commitments. The Lenders will have an opportunity to, but are not required to participate in the additional term loan facilities and/or revolving commitment increases. If the Lenders do not agree to provide such incremental facilities, the Company may request such additional and/or increased facilities from additional lenders. Interest on loans made under the Credit Agreement in U.S. Dollars accrues, at the Company's option, at a rate per annum equal to (1) the Base Rate (as defined below) plus a margin ranging from 0.25% to 1.25% depending upon the Company's consolidated leverage ratio or (2) LIBOR (determined with respect to deposits in U.S. Dollars) for an interest period to be selected by the Company plus a margin ranging from 1.25% to 2.25% depending upon the Company's consolidated leverage ratio (such margin, the "Applicable Margin"). The "Base Rate" is equal to a fluctuating rate equal to the highest of (a) the prime rate of the administrative agent, (b) ½ of 1% above the federal funds effective rate published by the Federal Reserve Bank of New York and (c) one-month LIBOR (determined with respect to deposits in U.S. Dollars) plus 1% . Interest on loans made under the Credit Agreement in alternative currencies accrues at a rate per annum equal to LIBOR (determined with respect to deposits in the applicable alternative currency) (other than loans made in Canadian Dollars, for which a special reference rate for Canadian Dollars applies) for an interest period to be selected by the Company plus the Applicable Margin. Commitment fees on the unused portion of the revolving commitments accrue at a rate per annum ranging from 0.20% to 0.45% depending upon the Company's consolidated leverage ratio. With respect to letters of credit, the Company will pay the administrative agent, for the account of the lenders under the revolving credit facility, letter of credit participation fees at a rate per annum equal to the applicable margin then in effect with respect to LIBOR-based loans under the revolving commitments on the face amount of all outstanding letters of credit. The Company also will pay HSBC Bank USA, N.A., as the issuing bank, a fronting fee for each letter of credit issued under the Credit Agreement at a rate equal to 0.125% per annum based on the maximum amount available to be drawn under each such letter of credit, as well as its customary documentation fees. All obligations of the Company under the Credit Agreement are unconditionally guaranteed by each of the Guarantors, which currently consist of all of the direct and indirect domestic subsidiaries of Semtech Corporation. Semtech Corporation and the Guarantors have also pledged substantially all of their assets, including sixty-five percent ( 65.0% ) of such Guarantor's equity interest in direct non-U.S. subsidiaries, to secure their obligations under the Credit Agreement, including the Company's owned real property located in Camarillo, California. The outstanding principal balance of the Term Loans is subject to repayment in quarterly installments. No amortization is required with respect to the revolving credit facility. The Company may voluntarily prepay borrowings under the Credit Agreement at any time and from time to time, without premium or penalty, other than customary "breakage costs" and fees for LIBOR-based loans. The Term Loans are required to be prepaid using the proceeds of certain dispositions of assets and receipt of insurance proceeds, subject to agreed-upon thresholds and exceptions and customary reinvestment rights. The Credit Agreement contains customary covenants, including limitations on Company’s ability to, among other things, incur indebtedness, create liens on assets, engage in certain fundamental corporate changes, make investments, sell or otherwise dispose of assets, repurchase stock, pay dividends or make similar distributions, engage in certain transactions with affiliates and make capital expenditures. In addition, the Company must comply with the following financial covenants, tested at the end of each fiscal quarter on a trailing four-quarter basis: (i) a minimum consolidated interest coverage ratio of 3.00 to 1.00 and (ii) a maximum consolidated leverage ratio of 3.00 to 1.00 provided that, such maximum consolidated leverage ratio may be increased to 3.25 to 1.00 or 3.50 to 1.00, as applicable, for the four consecutive fiscal quarters ending on or after the date of consummation of a permitted acquisition which constitutes a "Material Acquisition" under the Credit Agreement, subject to the satisfaction of certain conditions. As of April 29, 2018 , the Company was in compliance with all financial covenants. The Credit Agreement also contains customary provisions pertaining to events of default. If any event of default occurs, the principal, interest, and any other monetary obligations on all the then outstanding amounts can become due and payable immediately by action of the administrative agent acting upon the instructions of or with the consent of the Lenders representing more than 50% of the revolving commitments and outstanding term loans or automatically upon the occurrence of certain bankruptcy events related to the Company. As of April 29, 2018 , the interest rates payable on both the Term Loans and the Revolving Commitments was 3.51% . Scheduled maturities of current and long-term Term Loans are as follows: (in thousands) Fiscal Year Ending: 2019 $ 12,188 2020 18,750 2021 19,687 2022 76,875 Total debt $ 127,500 As of April 29, 2018 , we had $153.0 million of unused borrowing capacity under the Revolving Commitments, after deducting $97.0 million for draw down on the Revolving Commitments, which is due on or before November 12, 2021.

Income Taxes

Income Taxes	3 Months Ended
	Apr. 29, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate differs from the statutory federal income tax rate of 21% primarily due to regional mix of income and a partial release of the valuation allowance in the U.S. The valuation allowance was released in the current quarter as a result of the Company obtaining the information necessary to evaluate the impact of the Global Intangible Low-Taxed Income (“GILTI”) provisions, enacted as part of the Tax Cuts and Jobs Act (“Tax Act”) on December 22, 2017. This item was left open under Staff Accounting Bulletin 118 (“SAB 118”) in the financial statements for the year ended January 28, 2018 and the Company has now made a reasonable estimate based on the most current information available. The Tax Act made significant changes to U.S. income tax laws, including transitioning from a worldwide tax system to a territorial tax system. This change in the U.S. international tax system included the introduction of several new tax regimes that are effective as of January 1, 2018, including the GILTI provisions. The GILTI provisions effectively tax the foreign earnings of U.S. multinational companies at 10.5% , half the current corporate tax rate. During the three months ended April 29, 2018, the Company finalized its analysis regarding the interplay of the foreign tax credits associated with this income, which are allowed against the U.S. tax liability generated as a result of the GILTI provision, and the potential impact on the related valuation allowance. As a result, the Company recorded a tax benefit of $15.8 million related to the reduction of the valuation allowance on certain U.S. deferred tax assets generated prior to fiscal year 2019. While management believes the provisional amounts recorded during the three months ended April 29, 2018 and the year ended January 28, 2018 represent reasonable estimates of the ultimate impact U.S. tax reform will have on the Company's consolidated financial statements, it is possible the Company may continue to materially adjust these amounts for related administrative guidance, notices, implementation regulations, potential legislative amendments and interpretations as the Act continues to evolve. These adjustments could have an impact on the Company's tax assets and liabilities, effective tax rate, net income and earnings per share. The Company uses a two-step approach to recognize and measure uncertain tax positions ("UTP"). The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits (before federal impact of state items) is as follows: (in thousands) Balance at January 28, 2018 $ 16,059 Additions based on tax positions related to the current year 733 Balance as of April 29, 2018 $ 16,792 Included in the balance of gross unrecognized tax benefits at April 29, 2018 and January 28, 2018 , are $4.5 million and 3.9 million , respectively, of net tax benefits (after federal impact of state items), that, if recognized, would impact the effective tax rate, prior to consideration of any required valuation allowance. The liability for UTP is reflected within the Balance Sheets as follows: (in thousands) April 29, 2018 January 28, 2018 Deferred tax assets - non-current $ 12,252 $ 12,135 Other long-term liabilities 4,540 3,924 Total accrued taxes $ 16,792 $ 16,059 The Company’s policy is to include net interest and penalties related to unrecognized tax benefits within the "Provision for taxes" in the Statements of Income. Tax years prior to 2013 (the Company’s fiscal year 2014) are generally not subject to examination by the U.S. Internal Revenue Service ("IRS") except for items involving tax attributes that have been carried forward to tax years whose statute of limitations remains open. For state returns, the Company is generally not subject to income tax examinations for calendar years prior to 2012 (the Company’s fiscal year 2013). The Company has a significant tax presence in Switzerland for which Swiss tax filings have been examined through fiscal year 2017. The Company is also subject to routine examinations by various foreign tax jurisdictions in which it operates. The Company believes that adequate provisions have been made for any adjustments that may result from tax examinations. However, the outcome of tax audits cannot be predicted with certainty. If any issues addressed in the Company’s tax audits are resolved in a manner not consistent with the Company's expectations, the Company could be required to adjust its provision for income taxes in the period such resolution occurs. The Company’s regional income from continuing operations before taxes and equity in net losses of equity method investments is as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Domestic $ (7,700 ) $ (4,167 ) Foreign 2,603 19,745 Total $ (5,097 ) $ 15,578

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Apr. 29, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies In accordance with accounting standards regarding loss contingencies, the Company accrues an undiscounted liability for those contingencies where the incurrence of a loss is probable and the amount can be reasonably estimated. The Company also discloses the amount accrued and the amount of a reasonably possible loss in excess of the amount accrued, if such disclosure is necessary for its consolidated financial statements not to be misleading. The Company does not record liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated, or when the liability is believed to be only reasonably possible or remote. The Company evaluates, at least quarterly, developments in its legal matters that could affect the amount of liability that has been previously accrued, and makes adjustments as appropriate. Significant judgment is required to determine both probability and the estimated amount. The Company may be unable to estimate a possible loss or range of possible loss due to various reasons, including, among others: (i) if the damages sought are indeterminate; (ii) if the proceedings are in early stages, (iii) if there is uncertainty as to the outcome of pending appeals, motions or settlements, (iv) if there are significant factual issues to be determined or resolved, and (v) if there are novel or unsettled legal theories presented. In such instances, there is considerable uncertainty regarding the ultimate resolution of such matters, including a possible eventual loss, if any. Because the outcomes of litigation and other legal matters are inherently unpredictable, the Company’s evaluation of legal matters or proceedings often involves a series of complex assessments by management about future events and can rely heavily on estimates and assumptions. While the consequences of certain unresolved matters and proceedings are not presently determinable, and an estimate of the probable and reasonably possible loss or range of loss in excess of amounts accrued for such proceedings cannot be reasonably made, an adverse outcome from such proceedings could have a material adverse effect on the Company’s earnings in any given reporting period. However, in the opinion of management, after consulting with legal counsel, any ultimate liability related to current outstanding claims and lawsuits, individually or in the aggregate, is not expected to have a material adverse effect on the Company’s consolidated financial statements, as a whole. However, legal matters are inherently unpredictable and subject to significant uncertainties, some of which are beyond the Company’s control. As such, even though the Company intends to vigorously defend itself with respect to its legal matters, there can be no assurance that the final outcome of these matters will not materially and adversely affect the Company’s business, financial condition, operating results, or cash flows. From time to time, the Company is involved in various claims, litigation, and other legal actions that are normal to the nature of its business, including with respect to IP, contract, product liability, employment, and environmental matters. In the opinion of management, after consulting with legal counsel, any ultimate liability related to current outstanding claims and lawsuits, individually or in the aggregate, is not expected to have a material adverse effect on the Company’s consolidated financial statements, as a whole. The Company’s currently pending legal matters of note are discussed below: Environmental Matters The Company vacated a former facility in Newbury Park, California in 2002, but continues to address groundwater and soil contamination at the site. The Company’s efforts to address site conditions have been at the direction of the Los Angeles Regional Water Quality Control Board (“RWQCB”). In October 2013, an order was issued including a scope of proposed additional site work, monitoring, and proposed remediation activities. The Company filed appeals of the October 2013 order seeking reconsideration by the RWQCB and review by the State Water Resources Control Board ("SWRCB") of the removal of two other potentially responsible parties, and seeking clarification of certain other factual findings. In April 2015, the RWQCB denied the Company’s request to name the two other potentially responsible parties to the order, but did correct certain findings of fact identified by the Company in its petition for reconsideration. The SWRCB has not yet ruled on the Company’s petition for review of the RWQCB’s action as the petition was filed with a request it be held in abeyance. The Company has been complying with RWQCB orders and direction, and is implementing an approved remedial action plan (prepared by an environmental firm retained by the Company) addressing the cleanup of soil, groundwater, and soil vapor at the site. The Company has accrued liabilities where it is probable that a loss will be incurred and the cost or amount of loss can be reasonably estimated. Based on the latest determinations by the RWQCB and the most recent actions taken pursuant to the remedial action plan, the Company continues to estimate the range of probable loss between $4.1 million and $7.2 million . Given the uncertainties associated with environmental assessment and the remediation activities, the Company is unable to determine a best estimate within the range of loss. Therefore, the Company has recorded the minimum amount of probable loss. These estimates could change as a result of changes in planned remedial actions, further actions from the regulatory agency, remediation technology, and other factors. Indemnification The Company has entered into agreements with its current and former executives and directors indemnifying them against certain liabilities incurred in connection with the performance of their duties. The Company’s Certificate of Incorporation and Bylaws contain comparable indemnification obligations with respect to the Company’s current directors and employees. Product Warranties The Company’s general warranty policy provides for repair or replacement of defective parts. In some cases, a refund of the purchase price is offered. In certain instances the Company has agreed to other or additional warranty terms, including indemnification provisions. The product warranty accrual reflects the Company’s best estimate of probable liability under its product warranties. The Company accrues for known warranty issues if a loss is probable and can be reasonably estimated, and accrues for estimated incurred but unidentified issues based on historical experience. Historically, warranty expense has been immaterial to the Company’s consolidated financial statements. Earn-out Liability Pursuant to the terms of the amended earn-out arrangement ("Cycleo Earn-out") with the former shareholders of Cycleo SAS ("Cycleo Earn-out Beneficiaries"), which the Company acquired on March 7, 2012, the Company potentially may make payments totaling up to approximately $16.0 million based on the achievement of a combination of certain revenue and operating income milestones over a defined period ("Cycleo Defined Earn-out Period"). The Cycleo Defined Earn-out Period covers the period April 27, 2015 to April 26, 2020. For certain of the Cycleo Earn-out Beneficiaries, payment of the earn-out liability is contingent upon continued employment and is accounted for as post-acquisition compensation expense over the service period. The portion of the earn-out liability that is not dependent on continued employment is not considered as compensation expense. The Company has recorded a liability for the Cycleo Earn-out of $5.9 million and $5.5 million as of April 29, 2018 and January 28, 2018 , respectively, of which $2.2 million is expected to be paid within twelve months. Pursuant to the terms of the AptoVision Earn-out with the former shareholders of AptoVision ("AptoVision Earn-out Beneficiaries"), which the Company acquired on July 1, 2017, the Company potentially may make payments totaling up to approximately $47.0 million based on the achievement of a combination of certain net revenue, adjusted earnings and product development targets measured from the acquisition date through July 26, 2020. A summary of earn-out liabilities, included in "Accrued liabilities" and "Other long-term liabilities", by classification follows: Balance at April 29, 2018 Balance at January 28, 2018 (in thousands) Cycleo AptoVision Total Cycleo AptoVision Total Compensation expense $ 4,806 $ — $ 4,806 $ 4,408 $ — $ 4,408 Not conditional upon continued employment 668 21,000 21,668 668 21,000 21,668 Interest expense 444 — 444 444 — 444 Total liability $ 5,918 $ 21,000 $ 26,918 $ 5,520 $ 21,000 $ 26,520 Amount expected to be settled within twelve months $ 2,155 $ 8,688 $ 10,843

Concentration of Risk

Concentration of Risk	3 Months Ended
	Apr. 29, 2018
Risks and Uncertainties [Abstract]
Concentration of Risk	Concentration of Risk The following significant customers accounted for at least 10% of net sales in one or more of the periods indicated: Three Months Ended (percentage of net sales) April 29, 2018 April 30, 2017 Arrow Electronics (and affiliates) 12 % 9 % Trend-tek Technology Ltd (and affiliates) 12 % 10 % Samsung Electronics (and affiliates) 8 % 7 % Premier Technical Sales Korea, Inc. (and affiliates) (1) 5 % 7 % (1) Premier is a distributor with a concentration of sales to Samsung. The above percentages represent the Company's estimate of the sales activity related to Samsung that is passing through this distributor. The following table shows the customers that have an outstanding receivable balance that represents at least 10% of total net receivables for the periods indicated: Balance as of (percentage of net sales) April 29, 2018 January 28, 2018 Trend-tek Technology Ltd (and affiliates) 12 % 8 % Frontek Technology Corporation 10 % 9 % Outside Subcontractors and Suppliers The Company relies on a limited number of third-party subcontractors and suppliers for the production of silicon wafers, packaging and certain other tasks. Disruption or termination of supply sources or subcontractors, including due to natural disasters such as an earthquake or other causes, could delay shipments and could have a material adverse effect on the Company. Although there are generally alternate sources for these materials and services, qualification of the alternate sources could cause delays sufficient to have a material adverse effect on the Company. Several of the Company’s third-party subcontractors and suppliers, including third-party foundries that supply silicon wafers, are located in foreign countries, including China, Israel and Taiwan.A significant amount of the Company’s assembly and test operations are conducted by third-party contractors in China, Malaysia, Taiwan, Thailand, South Korea and the Philippines. For the first quarter of fiscal years 2019 and 2018 , respectively, approximately 14% and 21% , respectively, of the Company’s silicon in terms of cost of wafers was supplied by a third-party foundry in China, and these percentages could be higher in future periods. In the first quarter of fiscal year 2019 , authorized distributors accounted for approximately 69% of the Company’s net sales compared to approximately 64% in the first quarter of fiscal year 2018 , excluding consideration of any impact from the Warrant Shares. Generally, the Company does not have long-term contracts with its distributors and most can terminate th eir agreement with little or no notice. For the first quarter of fiscal year 2019 , the Company's two largest distributors were based in Asia.

Segment Information

Segment Information	3 Months Ended
	Apr. 29, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information Segment Information The Company’s CEO functions as the CODM. The Company’s CODM makes operating decisions and assesses performance based on these operating segments. As part of a realignment strategy, during the first quarter of fiscal year 2019, the Company restructured and combined the Power and High Reliability operating segment with the Wireless and Sensing operating segment to better align resources with our LoRa® initiatives. This resulted in the Company having three operating segments compared to previously having four operating segments. The three operating segments: Protection, Signal Integrity, and Wireless and Sensing, all have similar economic characteristics and have been aggregated into one reportable segment identified in the table below as the "Semiconductor Products Group". The Company’s assets are commingled among the various operating segments and the CODM does not use that information in making operating decisions or assessing performance. Therefore, the Company has not included asset information by segment below. Net sales by segment are as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Semiconductor Products Group $ 130,429 $ 143,802 Total $ 130,429 $ 143,802 Income by segment and reconciliation to consolidated operating income: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Semiconductor Products Group $ 40,812 $ 39,222 Operating income by segment 40,812 39,222 Items to reconcile segment operating income to consolidated income before taxes Share-based compensation 35,516 13,286 Intangible amortization 6,961 6,286 Other non-segment related expenses 1,432 1,204 Amortization of fair value adjustments related to acquired property, plant and equipment — 190 Interest expense, net 2,190 2,046 Non-operating expense, net (190 ) 632 (Loss) income before taxes $ (5,097 ) $ 15,578 Information by Product Line The Company operates exclusively in the semiconductor industry and primarily within the analog and mixed-signal sector. The table below provides net sales activity by product line on a comparative basis: Three Months Ended (in thousands, except percentages) April 29, 2018 April 30, 2017 Signal Integrity $ 65,599 50 % $ 68,058 49 % Protection 40,792 31 % 42,249 29 % Wireless and Sensing 45,539 35 % 38,775 26 % Other: Warrant Shares (1) (21,501 ) (16 )% (5,280 ) (4 )% Total net sales $ 130,429 100 % $ 143,802 100 % (1) The cost of the Warrant granted was recognized as an offset to net sales over the respective performance period. Information by Sales Channel Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Distributor $ 111,340 $ 100,542 Direct 40,590 48,540 Other: Warrant Shares (21,501 ) (5,280 ) Total net sales $ 130,429 $ 143,802 Geographic Information The Company generates virtually all of its sales from its Semiconductor Products Group through sales of analog and mixed-signal devices. Net sales activity by geographic region is as follows: Three Months Ended April 29, 2018 April 30, 2017 Asia-Pacific 68 % 75 % North America 27 % 22 % Europe 9 % 7 % Other: Warrant Shares (4 )% (4 )% 100 % 100 % The Company attributes sales to a country based on the ship-to address. The table below summarizes sales activity to countries that represented greater than 10% of total net sales for at least one of the periods presented: Three Months Ended (percentage of total sales) April 29, 2018 April 30, 2017 China (including Hong Kong) 50 % 52 % United States 14 % 9 %

Stock Repurchase Program

Stock Repurchase Program	3 Months Ended
	Apr. 29, 2018
Equity [Abstract]
Stock Repurchase Program	Stock Repurchase Program Stock Repurchase Program The Company maintains a stock repurchase program that was initially approved by its Board of Directors in March 2008. The stock repurchase program does not have an expiration date and the Company’s Board of Directors has authorized expansion of the program over the years. The following table summarizes activity under the program for the presented periods: Three Months Ended April 29, 2018 April 30, 2017 (in thousands, except number of shares) Shares Value Shares Value Shares repurchased under the stock repurchase program 645,114 $ 25,325 300,000 $ 9,961 Total treasury shares required 645,114 $ 25,325 300,000 $ 9,961 As of April 29, 2018 , the Company had repurchased $176.7 million in shares of its common stock under the program since inception and the remaining authorization under the program was $21.7 million . Under the program, the Company may repurchase its common stock at any time or from time to time, without prior notice, subject to market conditions and other considerations. The Company’s repurchases may be made through Rule 10b5-1 and/or Rule 10b-18 or other trading plans, open market purchases, privately negotiated transactions, block purchases or other transactions. The Company intends to fund repurchases under the program from cash on hand. The Company has no obligation to repurchase any shares under the program and may suspend or discontinue it at any time. On May 24, 2018, the Company's Board of Directors authorized the expansion of the stock repurchase program by $250.0 million , bringing the total available authorization under the program to $271.7 million .

Restructuring

Restructuring	3 Months Ended
	Apr. 29, 2018
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring From time to time, the Company takes steps to realign the business to focus on high-growth areas, provide customer value and make the Company more efficient. As a result, the Company has re-aligned resources and infrastructure, which resulted in restructuring expense of $0.3 million and $6.3 million as of April 29, 2018 and January 28, 2018 , respectively. Restructuring related liabilities are included in "Accrued liabilities" within the Balance Sheets as of April 29, 2018 and January 28, 2018 , respectively. Restructuring charges are presented in "Selling, general and administrative" within the Statements of Income. Activity under the restructuring plans is summarized in the following table: (in thousands) One-time employee termination benefits Contract commitments Total Balance at January 28, 2018 $ 4,063 $ 686 $ 4,749 Charges 346 — 346 Cash payments (2,691 ) (149 ) (2,840 ) Balance at April 29, 2018 $ 1,718 $ 537 $ 2,255

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Apr. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivatives and Hedging Activities The Company is exposed to certain risk arising from both its business operations and economic conditions and principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company, on a routine basis and in the normal course of business, experiences expenses denominated in Swiss Franc ("CHF"), Canadian Dollar ("CAD") and Great British Pound ("GBP"). Such expenses expose the Company to exchange rate fluctuations between these foreign currencies and the U.S. Dollar ("USD"). The Company uses derivative financial instruments in the form of forward contracts to mitigate risk associated with adverse movements in these foreign currency exchange rates on a portion of foreign denominated expenses expected to be realized during the current and following fiscal year. Currency forward contracts involve fixing the exchange rate for delivery of a specified amount of foreign currency on a specified date. The Company’s accounting treatment for these instruments is based on whether or not the instruments are designated as a hedging instrument. The Company is currently applying hedge accounting to all foreign currency derivatives and has designated these hedges as cash flow hedges. At April 29, 2018 , the Company had the following outstanding foreign exchange contracts: (in thousands) Foreign Exchange Contracts Number of Instruments Sell Notional Value Buy Notional Value Sell USD/Buy CAD Forward Contract 9 $ 12,829 C$ 16,500 Total 9 These contracts met the criteria for cash flow hedges and the unrealized gains or losses, after tax, are recorded as a component of "Accumulated other comprehensive loss" within the Balance Sheet. The effective portions of cash flow hedges are recorded in accumulated other comprehensive income or loss ("AOCI") until the hedged item is recognized in selling, general and administrative ("SG&A") expense within the Statements of Income when the underlying hedged expense is recognized. Any ineffective portions of cash flow hedges are recorded in "Non-operating expense, net" within the Company’s Statements of Income. The Company presents its derivative assets and liabilities at their gross fair values on the Balance Sheets. The Company had no outstanding foreign exchange contracts at January 28, 2018 . The table below summarizes the carrying values of derivative instruments as of April 29, 2018 : Carrying Values of Derivative Instruments as of April 29, 2018 (in thousands) Fair Value - Assets (2) Fair Value - (Liabilities) (2) Derivative Net Carrying Value Derivatives designated as hedging instruments Foreign exchange contracts (1) $ 64 $ — $ 64 Total derivatives $ 64 $ — $ 64 (1) Assets are included in "Other current assets" and liabilities are included in "Accrued liabilities" within the Balance Sheets. (2) The fair values of the foreign exchange forward contracts are valued using Level 2 inputs. Please refer to Note 6 . The following table summarizes the amount of income recognized from derivative instruments for the three months ended April 29, 2018 and April 30, 2017 as well as the line items within the accompanying Statements of Income where the results are recorded for cash flow hedges: Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain or Loss into Income (Effective Portion) Amount of Gain Reclassified from AOCI into Income (Effective Portion) Location of Gain or Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain or Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Three Months Ended Three Months Ended Three Months Ended (in thousands) April 29, 2018 April 30, 2017 April 29, 2018 April 30, 2017 April 29, 2018 April 30, 2017 Sell USD/Buy CAD Forward Contract $ 65 $ (35 ) SG&A $ (1 ) $ — SG&A $ — $ — Sell USD/Buy GBP Forward Contract — 234 SG&A — (59 ) SG&A — — $ 65 $ 199 $ (1 ) $ (59 ) $ — $ — The amount of gains related to the effective portion of derivative instruments designated as cash flow hedges included in AOCI within the Balance Sheets for the three months ended April 29, 2018 and April 30, 2017 was $0.1 million and $0.1 million , respectively. Any gains or losses under these contracts are expected to be realized and reclassified to selling, general and administrative expenses within the next nine months .

Organization and Basis of Pre23

Organization and Basis of Presentation (Policy)	3 Months Ended
	Apr. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Fiscal Year	Fiscal Year The Company reports results on the basis of 52 and 53 week periods and ends its fiscal year on the last Sunday in January. The other quarters generally end on the last Sunday of April, July and October. All quarters consist of 13 weeks except for one 14 -week period in the fourth quarter of 53 -week years. The first quarter of fiscal years 2019 and 2018 each consisted of 13 weeks.
Principles of Consolidation	Principles of Consolidation The accompanying interim unaudited consolidated financial statements have been prepared by the Company, in accordance with accounting principles generally accepted in the United States ("GAAP") and on the same basis as the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended January 28, 2018 . In the opinion of the Company, these interim unaudited consolidated financial statements contain all adjustments (consisting of normal recurring adjustments) necessary to present fairly, in all material respects, the financial position of the Company for the interim periods presented. All intercompany balances have been eliminated. Certain information and footnote disclosures normally included in annual consolidated financial statements have been condensed or omitted pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Because the interim unaudited consolidated financial statements do not include all of the information and notes required by GAAP for a complete set of consolidated financial statements, they should be read in conjunction with the audited consolidated financial statements and notes included in the Company's Annual Report on Form 10-K for the year ended January 28, 2018. The results reported in these interim unaudited consolidated financial statements should not be regarded as indicative of results that may be expected for any subsequent period or for the entire year. The Company’s interim unaudited consolidated statements of income are referred to herein as the "Statements of Income." The Company’s interim unaudited consolidated balance sheets are referred to herein as the "Balance Sheets" and interim unaudited consolidated statements of cash flows as the "Statements of Cash Flows.
Segment Information	Segment Information The Company’s Chief Executive Officer ("CEO") has been identified as the Chief Operating Decision Maker ("CODM") as defined by guidance regarding segment disclosures (see Note 13 for further discussion). Prior to the first quarter of fiscal year 2019, the Company had four operating segments. However as of April 29, 2018 , the Company identified three operating segments that aggregate into one reportable segment, the Semiconductor Products Group.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Standards Adopted In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers (Accounting Standards Codification ("ASC") 606), which requires an entity to recognize revenue from the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance addresses, in particular, contracts with more than one performance obligation, as well as the accounting for some costs to obtain or fulfill a contract with a customer, and provides for additional disclosures with respect to revenues and cash flows arising from contracts with customers. The Company adopted the standard, effective January 29, 2018, using the modified retrospective transition method which resulted in an adjustment to retained earnings for the cumulative effect of applying the standard to all contracts not completed as of the adoption date. The primary change associated with the adoption relates to the Company’s sales to distributors with return or price adjustment rights where the Company will no longer defer revenue until the resale by the distributor to the end customer, but rather, will record revenue at the time control transfers to the distributor. The Company estimated the effects of returns and allowances provided to these distributors. Upon adoption, including the effect of income taxes, opening retained earnings as of January 29, 2018 increased by $11.1 million net, as a result of these changes. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Asset Transfers Other Than Inventory (Topic 740). This accounting standard update is aimed at recognizing the income tax consequences of intra-entity transfers of assets other than inventory when they occur. This removes the exception to postpone the recognition of income tax consequences of intra-entity transfers until the asset has been sold to an outside party. In the first quarter of 2019, the Company adopted ASU 2016-16 using a modified retrospective transition method, resulting in a $1.8 million decrease in retained earnings, a $3.7 million net increase in deferred income tax assets, and a $5.5 million decrease in pre-paid taxes. Accounting Guidance Issued but Not Adopted as of April 29, 2018 In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815). This standard addresses narrow issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity. Part I addresses the complexity of accounting for certain financial instruments with down round features. Part II addresses the difficulty of navigating Topic 480, Distinguishing Liabilities from Equity, because of the existence of pending content in the ASC that results from the indefinite deferral of accounting requirements concerning mandatorily redeemable financial instruments of certain non-public entities and certain mandatorily redeemable non-controlling interests. The new standard is effective for interim and annual fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company does not expect the adoption of this pronouncement to have a material impact on the Company’s consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815). The new standard is designed to refine and expand hedge accounting for both financial (e.g., interest rate) and commodity risks. Its provisions create more transparency around how economic results are presented, both on the face of the financial statements and in the footnotes. It also makes certain targeted improvements to simplify the application of hedge accounting guidance. The new standard is effective for interim and annual fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption, including adoption in an interim period, is permitted. The Company is currently evaluating the impact this ASU will have on its consolidated condensed financial statements and disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which will require that substantially all leases be recognized by lessees on their balance sheets as a right-of-use asset and corresponding lease liability, including leases currently accounted for as operating leases. The new standard also will result in enhanced quantitative and qualitative disclosures, including descriptions of significant judgments made by management, to provide greater insight into the extent of expense recognized and expected to be recognized from existing leases. The standard requires modified retrospective adoption and will be effective for the Company as of the beginning of fiscal year 2020. The Company expects the valuation of right of use assets and lease liabilities, previously described as operating leases, to be the present value of the Company's forecasted future lease commitments. The Company is continuing to assess the overall impacts of the new standard, including the discount rate to be applied in these valuations.
Earnings Per Share	Basic earnings per common share is computed by dividing income available to common stockholders by the weighted-average number of shares of common stock outstanding during the reporting period. Diluted earnings per common share incorporates the incremental shares issuable, calculated using the treasury stock method, upon the assumed exercise of non-qualified stock options, the vesting of restricted stock units and performance unit awards if the conditions have been met.
Share-based Compensation, Warrant	The Warrant was issued by the Company to Comcast in connection with an agreement between the parties regarding the intended trial deployment by Comcast of a low-power wide-area Network ("LPWAN") in the United States, based on the Company’s LoRa® devices and wireless radio frequency technology. The Warrant is accounted for as equity and the cost is recognized as an offset to net sales over the respective performance period. The Warrant consists of five performance tranches. The cost associated with each tranche has been recognized based on the fair value at each reporting date until vesting which is the measurement date.
Share-based Compensation, Performance-based RSUs	The Company grants performance-based restricted stock units to select employees. The performance-based restricted stock units are valued as of the measurement date and expense is recognized on a straight line basis for the awards expected to vest based on the probability of attainment of the performance condition for each separately vesting portion of the award.
Fair Value of Financial Instruments	Assets and Liabilities Recorded at Fair Value on a Non-Recurring Basis The Company reduces the carrying amounts of its goodwill, intangible assets, long-lived assets and non-marketable equity securities to fair value when held for sale or determined to be impaired. As of April 29, 2018 and January 28, 2018 , the Company had not elected the fair value option for any financial assets and liabilities for which such an election would have been permitted. The fair values of the foreign exchange forward contracts are valued using Level 2 inputs. Foreign currency forward contracts are valued using readily available foreign currency forward and interest rate curves. The fair value of each contract is determined by comparing the contract rate to the forward rate and discounting to the present value. Contracts in a gain position are recorded in the Balance Sheets within the caption "Other current assets" and the value of contracts in a loss position are recorded within the caption "Accrued liabilities" within the Balance Sheets. Please see Note 16 for further discussion of the Company’s derivative instruments. The convertible debt is valued using probability weighted cash flows (Level 3 inputs). The AptoVision Earn-out liability is valued utilizing estimates of annual revenue, adjusted earnings and product development targets (Level 3 inputs) through July 2020. These estimates represent inputs for which market data are not available and are developed using the best information available about the assumptions that market participants would use when pricing the liability. The Cycleo Earn-out liability (see Note 11 ) is valued utilizing estimates of annual revenue and operating income (Level 3 inputs) through April 2020. These estimates represent inputs for which market data are not available and are developed using the best information available about the assumptions that market participants would use when pricing the liability. The Company measures contingent earn-out liabilities at fair value on a recurring basis using significant unobservable inputs classified within Level 3 of the fair value hierarchy. The Company uses a Monte Carlo valuation method as a valuation technique to determine the value of the earn-out liability. The significant unobservable inputs used in the fair value measurements are revenue projections over the earn-out period, and the probability outcome percentages assigned to each scenario. Significant increases or decreases to either of these inputs in isolation would result in a significantly higher or lower liability, with a higher liability capped by the contractual maximum of the contingent earn-out obligation. Ultimately, the liabilities will be equivalent to the amount paid, and the difference between the fair value estimate and amount paid will be recorded in earnings. For the Cycleo Earn-out and AptoVision Earn-out, these companies have business profiles comparable to a start-up company. Accordingly, their respective revenue projections are subject to significant revisions. This characteristic can result in volatile changes to the measurement of fair value for a given earn-out. The Company reviews and re-assesses the estimated fair value of contingent consideration on a recurring basis, and the updated fair value could differ materially from the previous estimates. Changes in the estimated fair value of the Company’s contingent earn-out liabilities related to the time component of the present value calculation are reported in "Interest expense" within the Statements of Income. Adjustments to the estimated fair value related to changes in all other unobservable inputs are reported in operating income. Instruments Not Recorded at Fair Value on a Recurring Basis Some of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate fair value due to their liquid or short-term nature. Such financial assets and financial liabilities include: cash and cash equivalents, net receivables, certain other assets, accounts payable, accrued expenses, accrued personnel costs, and other current liabilities. The Company’s long-term debt is not recorded at fair value on a recurring basis, but is measured at fair value for disclosure purposes.
Inventory	Inventories, consisting of material, material overhead, labor, and manufacturing overhead, are stated at the lower of cost (first-in, first-out) or market
Interest and Penalties on Unrecognized Tax Benefits	The Company’s policy is to include net interest and penalties related to unrecognized tax benefits within the "Provision for taxes" in the Statements of Income.
Commitments and Contingencies	In accordance with accounting standards regarding loss contingencies, the Company accrues an undiscounted liability for those contingencies where the incurrence of a loss is probable and the amount can be reasonably estimated. The Company also discloses the amount accrued and the amount of a reasonably possible loss in excess of the amount accrued, if such disclosure is necessary for its consolidated financial statements not to be misleading. The Company does not record liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated, or when the liability is believed to be only reasonably possible or remote. The Company evaluates, at least quarterly, developments in its legal matters that could affect the amount of liability that has been previously accrued, and makes adjustments as appropriate. Significant judgment is required to determine both probability and the estimated amount. The Company may be unable to estimate a possible loss or range of possible loss due to various reasons, including, among others: (i) if the damages sought are indeterminate; (ii) if the proceedings are in early stages, (iii) if there is uncertainty as to the outcome of pending appeals, motions or settlements, (iv) if there are significant factual issues to be determined or resolved, and (v) if there are novel or unsettled legal theories presented. In such instances, there is considerable uncertainty regarding the ultimate resolution of such matters, including a possible eventual loss, if any. Because the outcomes of litigation and other legal matters are inherently unpredictable, the Company’s evaluation of legal matters or proceedings often involves a series of complex assessments by management about future events and can rely heavily on estimates and assumptions. While the consequences of certain unresolved matters and proceedings are not presently determinable, and an estimate of the probable and reasonably possible loss or range of loss in excess of amounts accrued for such proceedings cannot be reasonably made, an adverse outcome from such proceedings could have a material adverse effect on the Company’s earnings in any given reporting period. However, in the opinion of management, after consulting with legal counsel, any ultimate liability related to current outstanding claims and lawsuits, individually or in the aggregate, is not expected to have a material adverse effect on the Company’s consolidated financial statements, as a whole. However, legal matters are inherently unpredictable and subject to significant uncertainties, some of which are beyond the Company’s control.
Product Warranties	Product Warranties The Company’s general warranty policy provides for repair or replacement of defective parts. In some cases, a refund of the purchase price is offered. In certain instances the Company has agreed to other or additional warranty terms, including indemnification provisions. The product warranty accrual reflects the Company’s best estimate of probable liability under its product warranties. The Company accrues for known warranty issues if a loss is probable and can be reasonably estimated, and accrues for estimated incurred but unidentified issues based on historical experience. Historically, warranty expense has been immaterial to the Company’s consolidated financial statements
Derivatives	The Company’s accounting treatment for these instruments is based on whether or not the instruments are designated as a hedging instrument. The Company is currently applying hedge accounting to all foreign currency derivatives and has designated these hedges as cash flow hedges. These contracts met the criteria for cash flow hedges and the unrealized gains or losses, after tax, are recorded as a component of "Accumulated other comprehensive loss" within the Balance Sheet. The effective portions of cash flow hedges are recorded in accumulated other comprehensive income or loss ("AOCI") until the hedged item is recognized in selling, general and administrative ("SG&A") expense within the Statements of Income when the underlying hedged expense is recognized. Any ineffective portions of cash flow hedges are recorded in "Non-operating expense, net" within the Company’s Statements of Income. The Company presents its derivative assets and liabilities at their gross fair values on the Balance Sheets.
Revenue	The Company derives its revenue primarily from the sale of semiconductor products into various end markets. Revenue is recognized when control of these products is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for these products. Control is generally transferred when products are shipped and, to a lesser extent, when the products are delivered. Recovery of costs associated with product design and engineering services are recognized during the period in which services are performed and are reported as a reduction to product development and engineering expense. Historically, these recoveries have not exceeded the cost of the related development efforts. The Company includes revenue related to granted technology licenses as part of "Net sales." Historically, revenue from these arrangements has not been significant though it is part of its recurring ordinary business. The Company determines revenue recognition through the following five steps: • Identification of the contract, or contracts, with a customer • Identification of the performance obligations in the contract • Determination of the transaction price • Allocation of the transaction price to the performance obligations in the contract • Recognition of revenue when, or as, performance obligations are satisfied The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. The Company’s revenue contracts generally represent a single performance obligation to sell its products to trade customers. Net sales reflect the transaction prices for contracts, which include units shipped at selling prices reduced by variable consideration. Determination of variable consideration requires judgment by the Company. Variable consideration includes expected sales returns and other price adjustments. Variable consideration is estimated using the expected value method considering all reasonably available information, including the Company’s historical experience and its current expectations, and is reflected in the transaction price when sales are recorded. Sales returns are generally accepted at the Company’s discretion or from distributors with such rights. The Company’s contracts with trade customers do not have significant financing components or non-cash consideration. The Company records net sales excluding taxes collected on its sales to its trade customers. The Company provides an assurance type warranty which is typically not sold separately and does not represent a separate performance obligation. The Company’s payment terms are generally aligned with shipping terms.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Apr. 29, 2018
Revenue from Contract with Customer [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following presents the amounts by which financial statement line items were affected in the current period due to the adoption of ASC 606 as compared with the guidance that was in effect before the change: Three Months Ended Statements of Income April 29, 2018 (in thousands, except per share amounts) Increase/(decrease) Net sales $ 4,462 Cost of sales 1,016 Provision for taxes 724 Net income 2,722 Earnings per share: Basic $ 0.04 Diluted $ 0.04 Balance Sheets April 29, 2018 (in thousands) Increase/(decrease) Deferred revenue $ (15,737 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Apr. 29, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Common Share	The computation of basic and diluted earnings per common share was as follows: Three Months Ended (in thousands, except per share amounts) April 29, 2018 April 30, 2017 Net income $ 12,382 $ 11,821 Weighted average common shares outstanding - basic 66,324 65,839 Dilutive effect of stock options and restricted stock units 1,871 1,537 Weighted average common shares outstanding - diluted 68,195 67,376 Basic earnings per common share $ 0.19 $ 0.18 Diluted earnings per common share $ 0.18 $ 0.18 Anti-dilutive shares not included in the above calculations 146 686

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Apr. 29, 2018
Share-based Compensation [Abstract]
Allocation Of Stock-Based Compensation	The following table summarizes pre-tax share-based compensation included in the Statements of Income for the three months ended April 29, 2018 and April 30, 2017 . Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Revenue offset $ 21,501 $ 5,280 Cost of sales 328 564 Selling, general and administrative 11,462 5,557 Product development and engineering 2,225 1,885 Share-based compensation $ 35,516 $ 13,286 Net change in share-based compensation capitalized into inventory $ — $ (414 )

Investments (Tables)

Investments (Tables)	3 Months Ended
	Apr. 29, 2018
Investments [Abstract]
Summary Of Investments	The following table summarizes the Company’s available-for-sale securities: April 29, 2018 January 28, 2018 (in thousands) Market Value Adjusted Cost Gross Unrealized Gain Market Value Adjusted Cost Gross Unrealized Gain Convertible debt $ 2,500 $ 2,500 $ — $ 1,960 $ 1,960 $ — Total other assets $ 2,500 $ 2,500 $ — $ 1,960 $ 1,960 $ —
Schedule Of Investments, Classified By Maturity Period	The following table summarizes the maturities of the Company’s available-for-sale securities: April 29, 2018 January 28, 2018 (in thousands) Market Value Adjusted Cost Market Value Adjusted Cost Within 1 year $ 2,000 $ 2,000 $ 1,960 $ 1,960 After 1 year through 5 years 500 500 — — Total investments $ 2,500 $ 2,500 $ 1,960 $ 1,960

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Apr. 29, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Financial assets and liabilities measured and recorded at fair value on a recurring basis were presented within the Company's Balance Sheets as follows: Fair Value as of April 29, 2018 Fair Value as of January 28, 2018 (in thousands) Total (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Financial assets: Cash equivalents $ 30,000 $ 30,000 $ — $ — $ — $ — $ — $ — Derivative financial instruments 64 — 64 — — — — — Convertible debt 2,500 — — 2,500 1,960 — — 1,960 Total financial assets $ 32,564 $ 30,000 $ 64 $ 2,500 $ 1,960 $ — $ — $ 1,960 Financial liabilities: AptoVision Earn-out $ 21,000 $ — $ — $ 21,000 $ 21,000 $ — $ — $ 21,000 Cycleo Earn-out 668 — — 668 668 — — 668 Total financial liabilities $ 21,668 $ — $ — $ 21,668 $ 21,668 $ — $ — $ 21,668
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	A reconciliation of the change in the earn-out liability during the three months ended April 29, 2018 is as follows: (in thousands) AptoVision Cycleo Total Balance at January 28, 2018 $ 21,000 $ 668 $ 21,668 Changes in the fair value of contingent earn-out obligations — — — Current acquisitions — — — Payments — — — Balance as of April 29, 2018 $ 21,000 $ 668 $ 21,668

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Apr. 29, 2018
Inventory Disclosure [Abstract]
Summary Of Inventories	Inventories, consisting of material, material overhead, labor, and manufacturing overhead, are stated at the lower of cost (first-in, first-out) or market and consist of the following: (in thousands) April 29, 2018 January 28, 2018 Raw materials $ 1,583 $ 1,651 Work in progress 42,078 46,884 Finished goods 21,797 22,532 Inventories $ 65,458 $ 71,067

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Apr. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Amounts of Goodwill	Changes in the carrying amount of goodwill by applicable reporting unit were as follows: (in thousands) Signal Integrity Wireless and Sensing Total Balance at January 28, 2018 $ 274,085 $ 67,812 $ 341,897 Additions — — — Balance at April 29, 2018 $ 274,085 $ 67,812 $ 341,897
Schedule of Finite-lived Intangible Assets Acquired	The following table sets forth the Company’s finite-lived intangible assets resulting from business acquisitions, which continue to be amortized: April 29, 2018 January 28, 2018 (in thousands) Estimated Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core technologies 5-8 years $ 164,930 $ (121,156 ) $ 43,774 $ 164,930 $ (115,628 ) $ 49,302 Customer relationships 3-10 years 34,031 (26,859 ) 7,172 34,031 (25,426 ) 8,605 Total finite-lived intangible assets $ 198,961 $ (148,015 ) $ 50,946 $ 198,961 $ (141,054 ) $ 57,907 Amortization expenses recorded in the Statements of Income for each period were as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Core technologies $ 5,528 $ 5,186 Customer relationships 1,433 1,100 Total amortization expense $ 6,961 $ 6,286
Schedule of Indefinite-Lived Intangible Assets	The following table sets forth the Company’s indefinite-lived intangible assets resulting from additions to IPR&D: (in thousands) Net Carrying Value Value at January 28, 2018 $ 2,300 In-process research and development through acquisitions — Value at April 29, 2018 $ 2,300

Credit Facilities (Tables)

Credit Facilities (Tables)	3 Months Ended
	Apr. 29, 2018
Debt Instruments [Abstract]
Schedule Maturities of Current and Long-term Term Loans	Scheduled maturities of current and long-term Term Loans are as follows: (in thousands) Fiscal Year Ending: 2019 $ 12,188 2020 18,750 2021 19,687 2022 76,875 Total debt $ 127,500

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Apr. 29, 2018
Income Tax Disclosure [Abstract]
Summary of Income Tax Contingencies	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits (before federal impact of state items) is as follows: (in thousands) Balance at January 28, 2018 $ 16,059 Additions based on tax positions related to the current year 733 Balance as of April 29, 2018 $ 16,792
Liability For Uncertain Tax Positions	The liability for UTP is reflected within the Balance Sheets as follows: (in thousands) April 29, 2018 January 28, 2018 Deferred tax assets - non-current $ 12,252 $ 12,135 Other long-term liabilities 4,540 3,924 Total accrued taxes $ 16,792 $ 16,059
Regional Income (Loss) From Continuing Operations Before Income Taxes	The Company’s regional income from continuing operations before taxes and equity in net losses of equity method investments is as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Domestic $ (7,700 ) $ (4,167 ) Foreign 2,603 19,745 Total $ (5,097 ) $ 15,578

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Apr. 29, 2018
Commitments and Contingencies Disclosure [Abstract]
Summary of Earn-out Liabilities by Classification	A summary of earn-out liabilities, included in "Accrued liabilities" and "Other long-term liabilities", by classification follows: Balance at April 29, 2018 Balance at January 28, 2018 (in thousands) Cycleo AptoVision Total Cycleo AptoVision Total Compensation expense $ 4,806 $ — $ 4,806 $ 4,408 $ — $ 4,408 Not conditional upon continued employment 668 21,000 21,668 668 21,000 21,668 Interest expense 444 — 444 444 — 444 Total liability $ 5,918 $ 21,000 $ 26,918 $ 5,520 $ 21,000 $ 26,520 Amount expected to be settled within twelve months $ 2,155 $ 8,688 $ 10,843

Concentration of Risk (Tables)

Concentration of Risk (Tables)	3 Months Ended
	Apr. 29, 2018
Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Schedule Of Significant Customers Accounting For At Least 10% Of Net Sales	The following significant customers accounted for at least 10% of net sales in one or more of the periods indicated: Three Months Ended (percentage of net sales) April 29, 2018 April 30, 2017 Arrow Electronics (and affiliates) 12 % 9 % Trend-tek Technology Ltd (and affiliates) 12 % 10 % Samsung Electronics (and affiliates) 8 % 7 % Premier Technical Sales Korea, Inc. (and affiliates) (1) 5 % 7 % (1) Premier is a distributor with a concentration of sales to Samsung. The above percentages represent the Company's estimate of the sales activity related to Samsung that is passing through this distributor. The following table shows the customers that have an outstanding receivable balance that represents at least 10% of total net receivables for the periods indicated: Balance as of (percentage of net sales) April 29, 2018 January 28, 2018 Trend-tek Technology Ltd (and affiliates) 12 % 8 % Frontek Technology Corporation 10 % 9 %

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Apr. 29, 2018
Segment Reporting Information [Line Items]
Net Sales by Segment	Net sales by segment are as follows: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Semiconductor Products Group $ 130,429 $ 143,802 Total $ 130,429 $ 143,802
Income by Segment and Reconciliation to Consolidated Operating Income	Income by segment and reconciliation to consolidated operating income: Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Semiconductor Products Group $ 40,812 $ 39,222 Operating income by segment 40,812 39,222 Items to reconcile segment operating income to consolidated income before taxes Share-based compensation 35,516 13,286 Intangible amortization 6,961 6,286 Other non-segment related expenses 1,432 1,204 Amortization of fair value adjustments related to acquired property, plant and equipment — 190 Interest expense, net 2,190 2,046 Non-operating expense, net (190 ) 632 (Loss) income before taxes $ (5,097 ) $ 15,578
Net Sales Activity By Product Line	The table below provides net sales activity by product line on a comparative basis: Three Months Ended (in thousands, except percentages) April 29, 2018 April 30, 2017 Signal Integrity $ 65,599 50 % $ 68,058 49 % Protection 40,792 31 % 42,249 29 % Wireless and Sensing 45,539 35 % 38,775 26 % Other: Warrant Shares (1) (21,501 ) (16 )% (5,280 ) (4 )% Total net sales $ 130,429 100 % $ 143,802 100 %
Schedule of Revenue from External Customers by Sales Channel	Three Months Ended (in thousands) April 29, 2018 April 30, 2017 Distributor $ 111,340 $ 100,542 Direct 40,590 48,540 Other: Warrant Shares (21,501 ) (5,280 ) Total net sales $ 130,429 $ 143,802
Net Sales Activity By Geographic Region	Net sales activity by geographic region is as follows: Three Months Ended April 29, 2018 April 30, 2017 Asia-Pacific 68 % 75 % North America 27 % 22 % Europe 9 % 7 % Other: Warrant Shares (4 )% (4 )% 100 % 100 %
Summary Of Sales Activity To Countries That Represented Greater Than 10% Of Total Net Sales	The table below summarizes sales activity to countries that represented greater than 10% of total net sales for at least one of the periods presented: Three Months Ended (percentage of total sales) April 29, 2018 April 30, 2017 China (including Hong Kong) 50 % 52 % United States 14 % 9 %

Stock Repurchase Program (Table

Stock Repurchase Program (Tables)	3 Months Ended
	Apr. 29, 2018
Equity [Abstract]
Class of Treasury Stock	The following table summarizes activity under the program for the presented periods: Three Months Ended April 29, 2018 April 30, 2017 (in thousands, except number of shares) Shares Value Shares Value Shares repurchased under the stock repurchase program 645,114 $ 25,325 300,000 $ 9,961 Total treasury shares required 645,114 $ 25,325 300,000 $ 9,961

Restructuring (Tables)

Restructuring (Tables)	3 Months Ended
	Apr. 29, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	Activity under the restructuring plans is summarized in the following table: (in thousands) One-time employee termination benefits Contract commitments Total Balance at January 28, 2018 $ 4,063 $ 686 $ 4,749 Charges 346 — 346 Cash payments (2,691 ) (149 ) (2,840 ) Balance at April 29, 2018 $ 1,718 $ 537 $ 2,255

Derivatives and Hedging Activ38

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Apr. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Open Foreign Currency Contracts	At April 29, 2018 , the Company had the following outstanding foreign exchange contracts: (in thousands) Foreign Exchange Contracts Number of Instruments Sell Notional Value Buy Notional Value Sell USD/Buy CAD Forward Contract 9 $ 12,829 C$ 16,500 Total 9
Summary of the Carrying Values of Derivative Instruments	The table below summarizes the carrying values of derivative instruments as of April 29, 2018 : Carrying Values of Derivative Instruments as of April 29, 2018 (in thousands) Fair Value - Assets (2) Fair Value - (Liabilities) (2) Derivative Net Carrying Value Derivatives designated as hedging instruments Foreign exchange contracts (1) $ 64 $ — $ 64 Total derivatives $ 64 $ — $ 64 (1) Assets are included in "Other current assets" and liabilities are included in "Accrued liabilities" within the Balance Sheets. (2) The fair values of the foreign exchange forward contracts are valued using Level 2 inputs. Please refer to Note 6 .
Summary of Gain (Loss) Recognized From Derivative Instruments	The following table summarizes the amount of income recognized from derivative instruments for the three months ended April 29, 2018 and April 30, 2017 as well as the line items within the accompanying Statements of Income where the results are recorded for cash flow hedges: Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain or Loss into Income (Effective Portion) Amount of Gain Reclassified from AOCI into Income (Effective Portion) Location of Gain or Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain or Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Three Months Ended Three Months Ended Three Months Ended (in thousands) April 29, 2018 April 30, 2017 April 29, 2018 April 30, 2017 April 29, 2018 April 30, 2017 Sell USD/Buy CAD Forward Contract $ 65 $ (35 ) SG&A $ (1 ) $ — SG&A $ — $ — Sell USD/Buy GBP Forward Contract — 234 SG&A — (59 ) SG&A — — $ 65 $ 199 $ (1 ) $ (59 ) $ — $ —

Organization and Basis of Pre39

Organization and Basis of Presentation (Fiscal Year) (Details)	3 Months Ended
	Apr. 29, 2018weeksweek	Apr. 30, 2017weeks
52 Week Fiscal Year [Member]
Organization And Basis Of Presentation [Line Items]
Number of weeks in the fiscal year reporting period	52
Number of weeks in a quarter for 52 week fiscal period	13	13
53 Week Fiscal Year [Member]
Organization And Basis Of Presentation [Line Items]
Number of weeks in the fiscal year reporting period	53
Number of weeks in the 4th quarter for 53 week fiscal period | week	14

Organization and Basis of Pre40

Organization and Basis of Presentation (Segment Information) (Details)	3 Months Ended	12 Months Ended
	Apr. 29, 2018reportable_segmentoperating_segment	Jan. 28, 2018operating_segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | operating_segment	3	4
Number of reportable segments | reportable_segment	1

Organization and Basis of Pre41

Organization and Basis of Presentation (Recent Accounting Pronouncements) (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Jan. 28, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Document Fiscal Year Focus	2,019
Retained earnings	$ 524,238	$ 502,346
Prepaid taxes	12,874	$ 11,809
Accounting Standards Update 2014-09 | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	11,100
Accounting Standards Update 2016-16 | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	1,800
Deferred tax assets	3,700
Prepaid taxes	$ 5,500

Revenue (Effect of Adoption on

Revenue (Effect of Adoption on Financial Statements) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017	Jan. 28, 2018
Statements of Income
Net sales	$ 130,429	$ 143,802
Cost of sales	58,960	58,887
Provision for taxes	(17,510)	3,757
Net income	$ 12,382	$ 11,821
Basic (in dollars per share)	$ 0.19	$ 0.18
Diluted (in dollars per share)	$ 0.18	$ 0.18
Balance Sheets
Other current assets	$ 20,143		$ 17,250
Accrued liabilities	54,400		60,832
Deferred revenue	4,973		$ 12,758
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Statements of Income
Net sales	4,462
Cost of sales	1,016
Provision for taxes	724
Net income	$ 2,722
Basic (in dollars per share)	$ 0.04
Diluted (in dollars per share)	$ 0.04
Balance Sheets
Deferred revenue	$ (15,737)

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 12,382	$ 11,821
Weighted average common shares outstanding - basic	66,324	65,839
Dilutive effect of options and restricted stock units	1,871	1,537
Weighted average common shares outstanding - diluted	68,195	67,376
Basic earnings per common share (in dollars per share)	$ 0.19	$ 0.18
Diluted earnings per common share (in dollars per share)	$ 0.18	$ 0.18
Anti-dilutive shares not included in the above calculations	146	686

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	Apr. 27, 2018shares	Oct. 05, 2016shares	Apr. 29, 2018USD ($)employee$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares subject to purchase under warrants		1,086,957
Warrants vested (in shares)	586,956
Warrant vesting costs | $			$ 21.5
Warrant vesting costs due to acceleration | $			$ 15.9
Number of securities called by warrants (in shares)			869,565
Document Fiscal Year Focus			2,019
Number of shares affected (in shares)			159,000
Number of employees affected | employee			8
Additional compensation cost | $			$ 2.8
Market Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards granted			200,442
Description of award vesting rights			one-third of the awards vesting each performance period
Performance Period One | Market Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period			1 year
Grant date fair value per unit | $ / shares			$ 33.02
Performance Period Two | Market Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period			2 years
Grant date fair value per unit | $ / shares			$ 34.85
Performance Period Three | Market Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period			3 years
Grant date fair value per unit | $ / shares			$ 36.52

Share-Based Compensation - Allo

Share-Based Compensation - Allocation of Share-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 35,516	$ 13,286
Inventories [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Net change in share-based compensation capitalized into inventory	0	(414)
Revenue Offset [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	21,501	5,280
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	328	564
Selling, General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	11,462	5,557
Product Development And Engineering [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 2,225	$ 1,885

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Other Assets [Member]
Investment [Line Items]
Total investment in a private entity	$ 30,000
Restricted deposits	3,000
Agency Securities [Member] | Level 1 [Member]
Investment [Line Items]
Investments in money market funds	$ 30,004	$ 0

Investments - Summary Of Invest

Investments - Summary Of Investments (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Investment [Line Items]
Available-for-sale securities, market value	$ 2,500	$ 1,960
Available-for-sale securities, adjusted cost	2,500	1,960
Available-for-sale securities, gross unrealized gain	0	0
Convertible debt
Investment [Line Items]
Available-for-sale securities, market value	2,500	1,960
Available-for-sale securities, adjusted cost	2,500	1,960
Available-for-sale securities, gross unrealized gain	$ 0	$ 0

Investments - Summary of Maturi

Investments - Summary of Maturities of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Investment [Line Items]
Available-for-sale securities, market value	$ 2,500	$ 1,960
Available-for-sale securities, adjusted cost	2,500	1,960
Within 1 Year [Member]
Investment [Line Items]
Available-for-sale securities, market value	2,000	1,960
Available-for-sale securities, adjusted cost	2,000	1,960
After 1 Year Through 5 Years [Member]
Investment [Line Items]
Available-for-sale securities, market value	500	0
Available-for-sale securities, adjusted cost	$ 500	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Term Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt	$ 127,500
Level 2 [Member] | Term Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt		$ 131,300
Level 2 [Member] | Revolving Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 97,000	$ 97,000

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Agency Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	$ 30,004	$ 0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	64	0
Total financial assets	32,564	1,960
Total financial liabilities	21,668	21,668
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	0	0
Total financial assets	30,000	0
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	64	0
Total financial assets	64	0
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	0	0
Total financial assets	2,500	1,960
Total financial liabilities	21,668	21,668
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	30,000	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	30,000	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	2,500	1,960
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	2,500	1,960
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc.
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	21,000	21,000
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	21,000	21,000
Fair Value, Measurements, Recurring [Member] | Cycleo
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	668	668
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	$ 668	$ 668

Fair Value Measurements - Level

Fair Value Measurements - Level 3 Reconciliation of the Earn-out Liability (Details) $ in Thousands	3 Months Ended
	Apr. 29, 2018USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 21,668
Changes in the fair value of contingent earn-out obligations	0
Current acquisitions	0
Payments	0
Ending balance	21,668
AptoVision Technologies Inc.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	21,000
Changes in the fair value of contingent earn-out obligations	0
Current acquisitions	0
Payments	0
Ending balance	21,000
Cycleo
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	668
Changes in the fair value of contingent earn-out obligations	0
Current acquisitions	0
Payments	0
Ending balance	$ 668

Inventories - Summary of Invent

Inventories - Summary of Inventories (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 1,583	$ 1,651
Work in progress	42,078	46,884
Finished goods	21,797	22,532
Inventories	$ 65,458	$ 71,067

Goodwill and Intangible Asset53

Goodwill and Intangible Assets - Narrative (Details) $ in Thousands	3 Months Ended
	Apr. 29, 2018USD ($)
Wireless and Sensing [Member]
Goodwill [Line Items]
Goodwill, Transferred from Other Product Group	$ 49,400

Goodwill and Intangible Asset54

Goodwill and Intangible Assets - Changes in Carrying Amounts of Goodwill (Details) $ in Thousands	3 Months Ended
	Apr. 29, 2018USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 341,897
Additions	0
Ending balance	341,897
Signal Integrity [Member]
Goodwill [Roll Forward]
Beginning balance	274,085
Additions	0
Ending balance	274,085
Wireless and Sensing [Member]
Goodwill [Roll Forward]
Beginning balance	67,812
Additions	0
Ending balance	$ 67,812

Goodwill and Intangible Asset55

Goodwill and Intangible Assets - Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Jan. 28, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 198,961	$ 198,961
Accumulated amortization	(148,015)	(141,054)
Net carrying amount	50,946	57,907
Core Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	164,930	164,930
Accumulated amortization	(121,156)	(115,628)
Net carrying amount	$ 43,774	49,302
Core Technologies [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	5 years
Core Technologies [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	8 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 34,031	34,031
Accumulated amortization	(26,859)	(25,426)
Net carrying amount	$ 7,172	$ 8,605
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	3 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	10 years

Goodwill and Intangible Asset56

Goodwill and Intangible Assets - Schedule of Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Goodwill [Line Items]
Intangible amortization	$ 6,961	$ 6,286
Core Technologies [Member]
Goodwill [Line Items]
Intangible amortization	5,528	5,186
Customer Relationships [Member]
Goodwill [Line Items]
Intangible amortization	$ 1,433	$ 1,100

Goodwill and Intangible Asset57

Goodwill and Intangible Assets - Schedule of Indefinite-lived Intangible Assets Resulting From Additions to IPR&D (Details) $ in Thousands	3 Months Ended
	Apr. 29, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance, net carrying amount	$ 2,300
In-process research and development through acquisitions	0
Ending balance, net carrying amount	$ 2,300

Credit Facilities - Narrative (

Credit Facilities - Narrative (Details) - USD ($)	Nov. 15, 2016	Apr. 29, 2018
Facilities, maximum borrowing capacity	$ 400,000,000
Maturity date of term loans and revolving commitments	Nov. 12, 2021
Facilities, amount outstanding	$ 247,000,000
Percentage of equity interest in direct non-U.S. subsidiaries that are included as pledged assets	65.00%
Minimum lenders represented as percentage of revolving commitments and outstanding term loans that may demand repayment in event of default	50.00%
Minimum [Member]
Interest coverage ratio	3
Total leverage ratio following a material acquisition	3.25
Maximum [Member]
Total leverage ratio	3
Total leverage ratio following a material acquisition	3.50
Base Rate [Member]
Description of variable rate basis	The "Base Rate" is equal to a fluctuating rate equal to the highest of (a) the prime rate of the administrative agent, (b) ½ of 1% above the federal funds effective rate published by the Federal Reserve Bank of New York and (c) one-month LIBOR (determined with respect to deposits in U.S. Dollars) plus 1%.
Base Rate [Member] | Minimum [Member]
Basis spread on variable rate	0.25%
Base Rate [Member] | Maximum [Member]
Basis spread on variable rate	1.25%
LIBOR [Member]
Basis spread on variable rate	1.00%
LIBOR [Member] | Minimum [Member]
Basis spread on variable rate	1.25%
LIBOR [Member] | Maximum [Member]
Basis spread on variable rate	2.25%
Federal Funds [Member]
Basis spread on variable rate	1.00%
Term Loans [Member]
Facilities, maximum borrowing capacity	$ 150,000,000
Facilities, amount outstanding	150,000,000
Interest rate payable at period end		3.51%
Swingline Loans [Member]
Facilities, maximum borrowing capacity	25,000,000
Facilities, amount outstanding		$ 0
Revolving Loans and Letters of Credit in Certain Foreign Currencies [Member]
Facilities, maximum borrowing capacity	40,000,000
Facilities, amount outstanding		0
Letter of Credit [Member]
Facilities, maximum borrowing capacity	$ 40,000,000
Facilities, amount outstanding		$ 0
Fronting fee percentage for each letter of credit issued	0.125%
Revolving Loans [Member]
Facilities, maximum borrowing capacity	$ 250,000,000
Facilities, amount outstanding	97,000,000
Undrawn revolving commitments	$ 153,000,000
Interest rate payable at period end		3.51%
Unused borrowing capacity		$ 153,000,000
Revolving Loans [Member] | Minimum [Member]
Facilities, unused capacity, commitment fee percentage	0.20%
Revolving Loans [Member] | Maximum [Member]
Facilities, unused capacity, commitment fee percentage	0.45%
Additional Term Loan Facilities Or Revolving Commitments [Member]
Facilities, maximum borrowing capacity	$ 150,000,000
United States of America, Dollars [Member]
Description of variable rate basis	(1) the Base Rate (as defined below) plus a margin ranging from 0.25% to 1.25% depending upon the Company's consolidated leverage ratio or (2) LIBOR (determined with respect to deposits in U.S. Dollars) for an interest period to be selected by the Company plus a margin ranging from 1.25% to 2.25% depending upon the Company's consolidated leverage ratio (such margin, the "Applicable Margin").

Credit Facilities - Scheduled M

Credit Facilities - Scheduled Maturities of Term Loans (Details) - Term Loans [Member] $ in Thousands	Apr. 29, 2018USD ($)
Debt Instrument [Line Items]
2,019	$ 12,188
2,020	18,750
2,021	19,687
2,022	76,875
Total debt	$ 127,500

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 29, 2018	Jan. 28, 2018
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	21.00%
Increase (decrease) In global tax rate, percent	10.50%
Income tax benefit	$ 15.8
Percentage of uncertain tax positions evaluating criteria	50.00%
Net tax benefits, if recognized, would impact the effective tax rate	$ 4.5	$ 3.9

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Contingencies (Details) $ in Thousands	3 Months Ended
	Apr. 29, 2018USD ($)
Income Tax Contingency [Line Items]
Beginning balance	$ 16,059
Additions based on tax positions related to the current year	733
Ending balance	$ 16,792

Income Taxes - Liability For Un

Income Taxes - Liability For Uncertain Tax Positions (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Income Tax Contingency [Line Items]
Liability for UTP	$ 16,792	$ 16,059
Non-current deferred tax asset [Member]
Income Tax Contingency [Line Items]
Liability for UTP	12,252	12,135
Other long-term liabilities [Member]
Income Tax Contingency [Line Items]
Liability for UTP	$ 4,540	$ 3,924

Income Taxes - Regional Income

Income Taxes - Regional Income (Loss) From Continuing Operations Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Income Tax Disclosure [Abstract]
Domestic	$ (7,700)	$ (4,167)
Foreign	2,603	19,745
(Loss) income before taxes and equity in net losses of equity method investments	$ (5,097)	$ 15,578

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018	Jul. 01, 2017
Commitments and Contingencies [Line Items]
Earn-out liability booked	$ 26,918	$ 26,520
Amount expected to be settled within twelve months	10,843
Cycleo
Commitments and Contingencies [Line Items]
Potential payments under earn-out arrangements, high estimate	16,000
Earn-out liability booked	5,918	5,520
Amount expected to be settled within twelve months	2,155
AptoVision Technologies Inc.
Commitments and Contingencies [Line Items]
Earn-out liability booked	21,000	$ 21,000
Amount expected to be settled within twelve months	8,688
Minimum [Member] | Environmental Issue
Commitments and Contingencies [Line Items]
Loss contingency, estimate of possible loss	4,100
Maximum [Member] | AptoVision Technologies Inc.
Commitments and Contingencies [Line Items]
Potential payments under earn-out arrangements, high estimate			$ 47,000
Maximum [Member] | Environmental Issue
Commitments and Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 7,200

Commitments and Contingencies65

Commitments and Contingencies - Summary of Earn-out Liability (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	$ 26,918	$ 26,520
Amount expected to be settled within twelve months	10,843
Compensation Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	4,806	4,408
Not Conditional Upon Continued Employment [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	21,668	21,668
Interest Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	444	444
Cycleo
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	5,918	5,520
Amount expected to be settled within twelve months	2,155
Cycleo | Compensation Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	4,806	4,408
Cycleo | Not Conditional Upon Continued Employment [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	668	668
Cycleo | Interest Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	444	444
AptoVision Technologies Inc.
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	21,000	21,000
Amount expected to be settled within twelve months	8,688
AptoVision Technologies Inc. | Compensation Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	0	0
AptoVision Technologies Inc. | Not Conditional Upon Continued Employment [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	21,000	21,000
AptoVision Technologies Inc. | Interest Expense [Member]
Business Acquisition, Contingent Consideration [Line Items]
Earn-out liability booked	$ 0	$ 0

Concentration of Risk - Narrati

Concentration of Risk - Narrative (Details)	3 Months Ended		12 Months Ended
	Apr. 29, 2018	Apr. 30, 2017	Jan. 28, 2018
Concentration Risk [Line Items]
Description of geographic concentration risk related to distributors	For the third quarter of fiscal year 2018, our two largest distributors were based in Asia.
Accounts Receivable [Member]
Concentration Risk [Line Items]
Minimum concentration risk threshold	10.00%		10.00%
Net sales [Member]
Concentration Risk [Line Items]
Minimum concentration risk threshold	10.00%
Concentration risk, percentage	100.00%	100.00%
Net sales [Member] | Distributor concentration risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	69.00%	64.00%
China | Cost of Silicon Wafers [Member] | Supplier concentration risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	21.00%

Concentration of Risk - Schedul

Concentration of Risk - Schedule of Significant Customers Accounting for at Least 10% of Net Sales During Period (Details)		3 Months Ended		12 Months Ended
		Apr. 29, 2018	Apr. 30, 2017	Jan. 28, 2018
Net sales [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		100.00%	100.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Trend-tek Technology Ltd And Affiliates [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		12.00%		8.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Frontek Technology Corporation [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		10.00%		9.00%
Customer Concentration Risk [Member] | Net sales [Member] | Arrow Electronics And Affiliates [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		12.00%	9.00%
Customer Concentration Risk [Member] | Net sales [Member] | Trend-tek Technology Ltd And Affiliates [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		12.00%	10.00%
Customer Concentration Risk [Member] | Net sales [Member] | Samsung Electronics And Affiliates [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		8.00%	7.00%
Customer Concentration Risk [Member] | Net sales [Member] | Premier Technical Sales Korea, Inc. And Affiliates [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	[1]	5.00%	7.00%
[1]	Premier is a distributor with a concentration of sales to Samsung. The above percentages represent the Company's estimate of the sales activity related to Samsung that is passing through this distributor.

Segment Information - Narrative

Segment Information - Narrative (Details)	3 Months Ended	12 Months Ended
	Apr. 29, 2018reportable_segmentoperating_segment	Jan. 28, 2018operating_segment
Segment Reporting Information [Line Items]
Number of operating segments | operating_segment	3	4
Number of reportable segments | reportable_segment	1
Net sales [Member]
Segment Reporting Information [Line Items]
Minimum concentration risk threshold	10.00%

Segment Information - Net Sales

Segment Information - Net Sales Activity by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Revenue from External Customer [Line Items]
Net sales	$ 130,429	$ 143,802
Semiconductor Products Group [Member]
Revenue from External Customer [Line Items]
Net sales	$ 130,429	$ 143,802

Segment Information - Income by

Segment Information - Income by Segment and Reconciliation to Income Before Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Segment Reporting Information [Line Items]
Operating income	$ (3,097)	$ 18,256
Items to reconcile segment operating income to consolidated income before taxes
Share-based compensation	35,516	13,286
Intangible amortization	6,961	6,286
Interest expense, net	2,190	2,046
Non-operating expense, net	(190)	632
(Loss) income before taxes and equity in net losses of equity method investments	(5,097)	15,578
Corporate, Non-Segment [Member]
Items to reconcile segment operating income to consolidated income before taxes
Share-based compensation	35,516	13,286
Intangible amortization	6,961	6,286
Other non-segment related expenses	1,432	1,204
Amortization of fair value adjustments related to acquired property, plant and equipment	0	190
Interest expense, net	2,190	2,046
Non-operating expense, net	(190)	632
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income	40,812	39,222
Semiconductor Products Group [Member]
Segment Reporting Information [Line Items]
Operating income	$ 40,812	$ 39,222

Segment Information - Revenue b

Segment Information - Revenue by Product Line (Details) - USD ($)	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Revenue from External Customer [Line Items]
Net sales	$ 130,429,000	$ 143,802,000
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales	65,599,000	68,058,000
Protection [Member]
Revenue from External Customer [Line Items]
Net sales	40,792,000	42,249,000
Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Net sales	45,539,000	38,775,000
Other: Warrant Shares
Revenue from External Customer [Line Items]
Net sales offset	$ (21,501,000)	$ (5,280,000)
Net sales [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	100.00%	100.00%
Net sales [Member] | Signal Integrity [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	50.00%	49.00%
Net sales [Member] | Protection [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	31.00%	29.00%
Net sales [Member] | Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	35.00%	26.00%
Net sales [Member] | Other: Warrant Shares
Revenue from External Customer [Line Items]
Concentration risk, percentage	(16.00%)	(4.00%)

Segment Information - Revenue72

Segment Information - Revenue by Sales Channel (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 130,429	$ 143,802
Sales Channel, Through Intermediary
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	111,340	100,542
Sales Channel, Directly to Consumer
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	40,590	48,540
Other: Warrant Shares
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue offset	$ (21,501)	$ (5,280)

Segment Information - Net Sal73

Segment Information - Net Sales Activity by Geographic Region (Details) - Net sales [Member]	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	100.00%	100.00%
Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	68.00%	75.00%
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	27.00%	22.00%
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	9.00%	7.00%
Other: Warrant Shares
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	(4.00%)	(4.00%)

Segment Information - Summary o

Segment Information - Summary of Sales Activity to Countries that Represented Greater than 10% of Total Net Sales (Details) - Net sales [Member]	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	100.00%	100.00%
Geographic Concentration Risk [Member] | China Including Hong Kong [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	50.00%	52.00%
Geographic Concentration Risk [Member] | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage	14.00%	9.00%

Stock Repurchase Program - Narr

Stock Repurchase Program - Narrative (Details) - USD ($)	May 24, 2018	Apr. 29, 2018
Equity, Class of Treasury Stock [Line Items]
Remaining authorization under stock repurchase program		$ 21,700,000
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Stock purchase authorized amount,Increase during the period	$ 250,000,000
Stock purchase authorized amount	$ 271,700,000

Stock Repurchase Program - Summ

Stock Repurchase Program - Summary of Stock Repurchases (Details) - USD ($) $ in Thousands	3 Months Ended		121 Months Ended
	Apr. 29, 2018	Apr. 30, 2017	Apr. 29, 2018
Equity, Class of Treasury Stock [Line Items]
Shares repurchased under the stock repurchase program, shares	645,114	300,000
Shares repurchased under the stock repurchase program, value	$ 25,325	$ 9,961	$ 176,700
Stock Repurchase Program WIth No Expiration Date [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased under the stock repurchase program, shares	645,114	300,000
Shares repurchased under the stock repurchase program, value	$ 25,325	$ 9,961

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 29, 2018	Jan. 28, 2018
Restructuring Reserve [Roll Forward]
Balance at January 28, 2018	$ 4,749
Charges	346	$ 6,300
Cash payments	(2,840)
Balance at April 29, 2018	2,255	4,749
One-time employee termination benefits
Restructuring Reserve [Roll Forward]
Balance at January 28, 2018	4,063
Charges	346
Cash payments	(2,691)
Balance at April 29, 2018	1,718	4,063
Contract commitments
Restructuring Reserve [Roll Forward]
Balance at January 28, 2018	686
Charges	0
Cash payments	(149)
Balance at April 29, 2018	$ 537	$ 686

Derivatives and Hedging Activ78

Derivatives and Hedging Activities - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Objectives for using derivative instruments	The Company is exposed to certain risk arising from both its business operations and economic conditions and principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company, on a routine basis and in the normal course of business, experiences expenses denominated in Swiss Franc ("CHF"), Canadian Dollar ("CAD") and Great British Pound ("GBP"). Such expenses expose the Company to exchange rate fluctuations between these foreign currencies and the U.S. Dollar ("USD"). The Company uses derivative financial instruments in the form of forward contracts to mitigate risk associated with adverse movements in these foreign currency exchange rates on a portion of foreign denominated expenses expected to be realized during the current and following fiscal year.
Amount of losses related to the effective portion of derivative instrument included in AOCI	$ 0.1	$ 0.1
Period over which any gains or losses under foreign exchange contracts are expected to be realized	9 months

Derivatives and Hedging Activ79

Derivatives and Hedging Activities - Summary of Open Foreign Currency Contracts (Details) $ in Thousands, $ in Thousands	Apr. 29, 2018CAD ($)	Apr. 29, 2018USD ($)
Derivative [Line Items]
Number of Instruments	9	9
Sell USD/Buy CAD Forward Contract [Member]
Derivative [Line Items]
Number of Instruments	9	9
Short [Member] | Sell USD/Buy CAD Forward Contract [Member]
Derivative [Line Items]
Notional Value		$ 12,829
Long [Member] | Sell USD/Buy CAD Forward Contract [Member]
Derivative [Line Items]
Notional Value	$ 16,500

Derivatives and Hedging Activ80

Derivatives and Hedging Activities - Summary of the Carrying Values of Derivative Instruments (Details) - USD ($)		Apr. 29, 2018	Jan. 28, 2018
Derivatives, Fair Value [Line Items]
Fair Value - Assets	[1],[2]	$ 64,000
Fair Value - (Liabilities)	[1],[2]	0
Derivative Net Carrying Value		64,000
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Net Carrying Value	[1]	64,000	$ 0
Level 2 [Member] | Foreign Exchange Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Value - Assets	[1],[2]	64,000
Level 2 [Member] | Foreign Exchange Contract [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair Value - (Liabilities)	[1],[2]	$ 0
[1]	Assets are included in "Other current assets" and liabilities are included in "Accrued liabilities" within the Balance Sheets.
[2]	The fair values of the foreign exchange forward contracts are valued using Level 2 inputs. Please refer to Note 6.

Derivatives and Hedging Activ81

Derivatives and Hedging Activities - Summary of Gain (Loss) Recognized From Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 29, 2018	Apr. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	$ 65	$ 199
SG&A
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss reclassified from AOCI into income (effective portion)	(1)	(59)
Amount of gain (loss) recognized into income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0
Sell USD/Buy CAD Forward Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	65	(35)
Sell USD/Buy CAD Forward Contract [Member] | SG&A
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss reclassified from AOCI into income (effective portion)	(1)	0
Amount of gain (loss) recognized into income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0
Sell USD/Buy GBP Forward Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	0	234
Sell USD/Buy GBP Forward Contract [Member] | SG&A
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss reclassified from AOCI into income (effective portion)	0	(59)
Amount of gain (loss) recognized into income on derivative (ineffective portion and amount excluded from effectiveness testing)	$ 0	$ 0