Document and Entity Information	6 Months Ended
	Jun. 29, 2013	Aug. 02, 2013
Document Information [Line Items]
Entity Registrant Name	LATTICE SEMICONDUCTOR CORP
Entity Central Index Key	0000855658
Document Type	10-Q
Document Period End Date	Jun. 29, 2013
Amendment Flag	false
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-28
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		116,097,047