Note 3 - Revenue From Contracts With Customers (Details Textual) - USD ($) $ in Millions	12 Months Ended
Jan. 02, 2021	Dec. 28, 2019
Revenue From Contract With Customer, Processing Of Return Merchandise Authorizations	$ 6.1	$ 5.0
Revenue From Contract With Customer, Net Impact From Release Of Accruals Offsetting By Return Merchandise Authorization	$ 0.9	$ 0.1

Represents net impact from release of accruals offsetting by return merchandise authorization for revenue from contract with customer.

No definition available.

Name:	lscc_RevenueFromContractWithCustomerNetImpactFromReleaseOfAccrualsOffsettingByReturnMerchandiseAuthorization
Namespace Prefix:	lscc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration