Note 3 - Revenue From Contracts With Customers (Details Textual) $ in Millions	9 Months Ended
Sep. 26, 2020 USD ($)
Revenue From Contract With Customer, Processing Of Return Merchandise Authorizations	$ 3.0
Revenue From Contract With Customer, Net Impact From Release Of Accruals Offsetting By Return Merchandise Authorization	$ 0.4

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