Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Jan. 31, 2013	Jun. 29, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	ATMEL CORP
Entity Central Index Key	0000872448
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Entity Voluntary Filers	No
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,814,721,375
Entity Common Stock, Shares Outstanding		439,341,816	419,481,576
Entity Well Known Seasoned Issuer	Yes
Document Fiscal Focus	2012
Document Fiscal Period Focus	FY