Document and Entity Information
| Document and Entity Information | Oct. 01, 2020 |
| Cover [Abstract] | |
| Entity Registrant Name | SEMTECH CORP |
| Amendment Flag | true |
| Entity Central Index Key | 0000088941 |
| Document Type | 8-K/A |
| Document Period End Date | Oct. 1, 2020 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-06395 |
| Entity Tax Identification Number | 95-2119684 |
| Entity Address, Address Line One | 200 Flynn Road |
| Entity Address, City or Town | Camarillo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 93012-8790 |
| City Area Code | 805 |
| Local Phone Number | 498-2111 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | SMTC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Description | As previously reported on the Initial Form 8-K filed on October 1, 2020 (the “Initial Form 8-K”), the Board of Directors (the “Board”) of Semtech Corporation (the “Company”) had appointed each of Paula LuPriore and Martin S.J. Burvill to serve as a director of the Company effective October 1, 2020. The Board has determined that each of Ms. LuPriore and Mr. Burvill is an independent director under the listing standards of the Nasdaq Stock Market (“Nasdaq”). As of the date of the Initial Form 8-K, Ms. LuPriore and Mr. Burvill had not been appointed to any committees of the Board. |