Organization and Basis of Presentation	12 Months Ended
Organization and Basis of Presentation	Jan. 26, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Semtech Corporation (together with its consolidated subsidiaries, the "Company" or "Semtech") is a global supplier of high-performance analog and mixed-signal semiconductors and advanced algorithms. 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. Basis of Presentation 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 fiscal years 2020, 2019 and 2018 each consisted of 52 weeks. Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). The Company’s Consolidated Statements of Income are referred to herein as the "Statements of Income," the Company’s Consolidated Balance Sheets are referred to herein as the "Balance Sheets" and the Company's Consolidated Statements of Cash Flows are referred to herein as the "Statements of Cash Flows." In the opinion of the Company, all adjustments of a normal and recurring nature necessary for a fair presentation, in all material respects, of the consolidated financial statements have been made. All intercompany balances have been eliminated. The Company consolidates entities that are not variable interest entities ("VIEs") when it owns, directly or indirectly, a majority interest in the entity or is otherwise able to control the entity. The Company consolidates VIEs in accordance with Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 810, "Consolidation." Entities for which the Company owns an interest, but does not consolidate, are accounted for under the equity method or cost method of accounting as minority investments and are included in “Other Assets” within the Balance Sheets. The ownership interest in a consolidated subsidiary of the Company held by outside parties is included in “Noncontrolling Interest” within the Balance Sheets. Use of Estimates The preparation of the consolidated 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 consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Correction of Immaterial Errors During the fourth quarter of fiscal year 2020, management identified certain immaterial errors related to share-based compensation expense of market-based awards granted during fiscal years 2018, 2019 and 2020. The errors resulted from adjustments to the grant date fair value of the market-based awards that were incorrectly accounted for as performance-based awards. The Company has corrected its consolidated financial statements for these errors for all annual periods presented in this Annual Report on Form 10-K, as well as the unaudited interim financial information presented in Note 21. Refer to Note 20 for a discussion of the Company's assessment of the errors and impact on its consolidated financial statements.