Document and Entity Information - USD ($)	12 Months Ended
	Dec. 30, 2017	Mar. 02, 2018	Jul. 01, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	LATTICE SEMICONDUCTOR CORP
Entity Central Index Key	0000855658
Document Type	10-K
Document Period End Date	Dec. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-30
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		124,210,928
Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Filer	No
Entity Public Float			$ 613,585,307