Organization and Basis of Presentation	12 Months Ended
Jan. 29, 2017
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 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, 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 fiscal years ended January 29, 2017 and January 25, 2015 each consisted of 52 weeks. The fiscal year ended January 31, 2016 consisted of 53 weeks. Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). All intercompany balances have been eliminated. On March 4, 2015, the Company completed the acquisition of Triune Systems, L.L.C. ("Triune"). On January 13, 2015, the Company completed the acquisition of select assets from EnVerv, Inc. ("EnVerv"). The consolidated financial statements include the operating results of Triune and EnVerv commencing as of the acquisition dates. 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 16 for further discussion). In fiscal year 2016, the Company identified five operating segments in total. Four of the operating segments aggregated 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. As a result, the financial activity associated with the Systems Innovation Group was reported separately from the Company's Semiconductor Products Group. This separate reporting was included in the "All others" category. On August 5, 2016, the Company completed its divestiture of its Snowbush Intellectual Property ("Snowbush IP") business (previously part of the Company’s Systems Innovation Group) to Rambus Inc. ("Rambus") for a purchase price of $32.0 million in cash along with the opportunity to receive additional payments from Rambus through 2022 based upon a percentage of sales by Rambus of new products expected to be developed by Rambus from the disposed assets. Therefore, as of January 29, 2017, the Company no longer has a Systems Innovation Group or an "All others" category, resulting in four operating segments that aggregate into one reportable segment, the Semiconductor Products Group. 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.

Organization and Basis of Presentation

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, 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 fiscal years ended January 29, 2017 and January 25, 2015 each consisted of 52 weeks. The fiscal year ended January 31, 2016 consisted of 53 weeks.

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). All intercompany balances have been eliminated.

On March 4, 2015, the Company completed the acquisition of Triune Systems, L.L.C. ("Triune"). On January 13, 2015, the Company completed the acquisition of select assets from EnVerv, Inc. ("EnVerv"). The consolidated financial statements include the operating results of Triune and EnVerv commencing as of the acquisition dates.

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 16 for further discussion). In fiscal year 2016, the Company identified five operating segments in total. Four of the operating segments aggregated 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. As a result, the financial activity associated with the Systems Innovation Group was reported separately from the Company's Semiconductor Products Group. This separate reporting was included in the "All others" category. On August 5, 2016, the Company completed its divestiture of its Snowbush Intellectual Property ("Snowbush IP") business (previously part of the Company’s Systems Innovation Group) to Rambus Inc. ("Rambus") for a purchase price of $32.0 million in cash along with the opportunity to receive additional payments from Rambus through 2022 based upon a percentage of sales by Rambus of new products expected to be developed by Rambus from the disposed assets. Therefore, as of January 29, 2017, the Company no longer has a Systems Innovation Group or an "All others" category, resulting in four operating segments that aggregate into one reportable segment, the Semiconductor Products Group.

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.