Note 9 - Stock-based Compensation - Share Based Compensation Performance Shares Award Outstanding (Details) - Performance Shares [Member] shares in Thousands	3 Months Ended
Apr. 02, 2022 shares
Balance, Shares (in shares)	1,246
Granted, Shares (in shares)	183
Effect of vesting multiplier, Shares (in shares)	358
Vested, Shares (in shares)	(638)
Balance, Shares (in shares)	1,149

The number of shares awarded and vested due to the effect of the vesting multiplier during the period on stock (or unit) option and non-option instrument plans.

No definition available.

Name:	lscc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndNonOptionEquityInstrumentsNonvestedEffectOfVestingMultiplier
Namespace Prefix:	lscc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration