Organization and Basis of Presentation (Policy)	9 Months Ended
Organization and Basis of Presentation (Policy)	Oct. 25, 2015
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 53-week years. The third quarter of fiscal years 2016 and 2015 each consisted of 13 weeks.
Principles of Consolidation	Principles of Consolidation The accompanying interim condensed consolidated financial statements have been prepared by the Company, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). In the opinion of the Company, these unaudited 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 significant intercompany balances have been eliminated. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been condensed or omitted pursuant to such rules and regulations, and the Company believes that the included disclosures are adequate to make the information presented not misleading. The Company evaluated all subsequent events through the date these interim condensed consolidated financial statements were issued. In January 2015, the Company completed the acquisition of EnVerv, Inc. (“EnVerv”). In March 2015, the Company completed the acquisition of Triune Systems, L.L.C. (“Triune”). These interim condensed consolidated financial statements include the results of operations of EnVerv and Triune commencing as of their acquisition dates. These interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended January 25, 2015. The results reported in these interim condensed consolidated financial statements should not be regarded as indicative of results that may be expected for any subsequent period or for the entire year.
Segment Information	Segment Information In the first quarter of fiscal year 2016, the Company completed a reassessment of its operations in light of its recent strategic business decisions. Based on this reassessment, the Company has identified five operating segments in total. Four of the operating segments aggregate into one reportable segment, the Semiconductor Products Group. The remaining operating segment, the Systems Innovation Group (shown as “All others”), could not be aggregated with the other operating segments and did not meet the criteria for a separate reportable segment as defined by the guidance regarding segment disclosure. The Company’s Chief Executive Officer (“CEO”) has been identified as the Chief Operating Decision Maker (“CODM”) as defined by the segment disclosure guidance (see Note 14 for further discussion) and now receives discrete financial information pertaining to the Systems Innovation Group. As a result, the financial activity associated with the Systems Innovation Group is being reported separately from the Company’s reportable segment. This separate reporting is included in the “All others” category.
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 as of 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 Pronouncements In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes, which eliminates the current requirement for companies to present deferred tax liabilities and assets as current and non-current in a classified balance sheet. Instead, companies will be required to classify all deferred tax assets and liabilities as non-current. The amendments are effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Earlier application is permitted. The Company is evaluating the effect of adopting this pronouncement, but the adoption is not expected to have a material impact on the Company’s consolidated financial statements. In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. ASU 2014-08 changes the requirements for reporting discontinued operations in FASB Accounting Standards Codification (“ASC”) Subtopic 205-20, such that a disposal of a component of an entity or a group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. ASU 2014-08 requires an entity to present, for each comparative period, the assets and liabilities of a disposal group that includes a discontinued operation separately in the asset and liability sections, respectively, of the statement of financial position, as well as additional disclosures about discontinued operations. Additionally, ASU 2014-08 requires disclosures about a disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements and expands the disclosures about an entity’s significant continuing involvement with a discontinued operation. The Company adopted the provisions of this new accounting standard at the beginning of fiscal year 2016, and has assessed the impact on its consolidated financial statements to be immaterial. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which requires an entity to recognize revenue from the transfer 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. Public entities are required to apply the amendments on either a full- or modified-retrospective basis for annual periods beginning after December 15, 2017 and for interim periods within those annual periods. This update will be effective for the Company beginning in the first quarter of fiscal year 2018. Early adoption is not permitted. The Company is currently assessing the basis of adoption and evaluating the impact of the adoption of the update on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. The new standard intends to simplify the presentation of debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability. The new guidance is effective for annual reporting periods beginning after December 15, 2015, including interim reporting periods within that reporting period and early application is permitted. The Company plans to adopt the provisions of this new accounting standard at the beginning of fiscal year 2017. The adoption of this standard is not expected to have a significant impact on the Company’s consolidated financial statements.
Earnings Per Share	Basic earnings per common share is computed by dividing net 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 incorporate the incremental shares issuable, calculated using the treasury stock method, upon the assumed exercise of stock options and the vesting of restricted stock.
Revenue Recognition	Revenue Recognition The Company recognizes product revenue when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable and collectability is reasonably assured. Recovery of costs associated with product design and engineering services are recognized during the period in which services are performed. The product design and engineering recovery, when recognized, will be 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 in “Net sales” within the condensed consolidated statements of operations. Historically, revenue from these arrangements has not been significant though it is part of the Company’s recurring ordinary business. The Company defers revenue recognition on shipment of products to certain customers, principally distributors, under agreements which provide for limited pricing credits or return privileges, until these products are sold through to end-users or the return privileges lapse. For sales subject to certain pricing credits or return privileges, the amount of future pricing credits or inventory returns cannot be reasonably estimated given the relatively long period in which a particular product may be held by the customer. Therefore, the Company has concluded that sales to customers under these arrangements are not fixed and determinable at the date of the sale and revenue recognition has been deferred. The Company estimates the deferred gross margin on these sales by applying an average gross profit margin to the actual gross sales. The average gross profit margin is calculated for each category of material using standard costs which is expected to approximate actual costs at the date of sale. The estimated deferred gross margins on these sales, where there are no outstanding receivables, are included in “Deferred revenue” within the condensed consolidated balance sheets. The Company records a provision for estimated sales returns and rebates in the same period as the related revenues are recorded. The Company bases these estimates on historical sales returns, rebates and other known factors. Actual returns could be different from Company estimates and current provisions for sales returns and allowances, resulting in future charges to earnings. The Company reviews material subject to return for impairment for purposes of computing deferred cost of sales. There were no significant impairments of deferred cost of sales in the third quarter or first nine months of fiscal year 2016 or fiscal year 2015.
Share-based Compensation, Option and Incentive Plans	Stock-based Payment Arrangements The Company has various equity award plans that provide for granting stock-based awards to employees and non-employee directors of the Company. The plans provide for the granting of several available forms of stock-based compensation. As of October 25, 2015, the Company has granted stock options, restricted stock and restricted stock units under the plans and has also issued some stock-based compensation outside of the plans, including stock options, restricted stock and restricted stock units issued as inducements to join the Company. Grant Date Fair Values and Underlying Assumptions: Contractual Terms The Company uses the Black-Scholes pricing model to value stock options. The estimated fair value of restricted stock units, for which vesting is not linked to a market condition, is calculated based on the market price of the Company’s common stock on the date of grant. For restricted stock units that vest according to a market condition, the Company uses a Monte Carlo simulation model to value the award. Some of the restricted stock units granted in the first nine months of fiscal year 2016 and prior years are classified as liabilities rather than equity. For grants classified as equity, stock-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized as an expense over the grantee’s requisite service period. For grants classified as liabilities, stock-based compensation cost is measured at fair value at the end of each reporting period until the date of settlement, and is recognized as an expense over the grantee’s requisite service period. Expected volatilities are based on historical volatility using daily and monthly stock price observations.
Investments	Investments that have original maturities of three months or less are accounted for as cash equivalents. This includes money market funds, time deposits and United States (“U.S.”) government obligations. Temporary and long-term investments consist of government, bank and corporate obligations, with original maturity dates in excess of three months. Temporary investments have original maturities in excess of three months, but mature within twelve months of the balance sheet date. Long-term investments have original maturities in excess of twelve months. The Company determines the cost of securities sold based on the specific identification method. Realized gains or losses are reported in “Non-operating expense, net” within the condensed consolidated statements of operations. The Company classifies its investments as “available-for-sale” because it may sell some securities prior to maturity. The Company’s investments are subject to market risk, primarily interest rate and credit risks. The Company’s investments are managed by a limited number of outside professional managers that operate within investment guidelines set by the Company. These guidelines include specified permissible investments, minimum credit quality ratings and maximum average duration restrictions and are intended to limit market risk by restricting the Company’s investments to high quality debt instruments with relatively short-term maturities.
Fair Value of Financial Instruments	Available-for-sale securities included in Level 2 are valued utilizing inputs obtained from an independent service (the “Service”), which uses quoted market prices for identical or comparable instruments rather than direct observations of quoted prices in active markets. The Service gathers observable inputs for all of our fixed income securities from a variety of industry data providers, for example, large custodial institutions and other third-party sources. Once the observable inputs are gathered by the Service, all data points are considered and an average price is determined. The Service’s providers utilize a variety of inputs to determine their quoted prices. The Company reviews and evaluates the values provided by the Service and agrees with the valuation methods and assumptions used in determining the fair value of investments. The Company believes this method provides a reasonable estimate for fair value. 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. 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.
Goodwill Policy	Goodwill is not amortized, but is tested for impairment using a two-step method on an annual basis and whenever events or changes in circumstances indicate that the carrying value may not be recoverable. The recoverability of goodwill is measured at the reporting unit level by comparing the reporting unit’s carrying amount, including goodwill, to the fair market value of the reporting unit. Goodwill is allocated to three reporting units (Signal Integrity, Power and High Reliability and Wireless, Sensing and Timing) (see Note 14). 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.
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 warranty terms, including some 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.