FAIR VALUE OF ASSETS AND LIABILITIES (Narrative) (Details)	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Maximum percentage of assets measured using Level 3 valuation methodologies to total assets	1.00%	1.00%

Represents the maximum percentage of assets measured using Level 3 valuation methodologies to total assets.

No definition available.

Name:	atml_MaximumPercentageOfAssetsMeasuredUsingLevel3ValuationMethodologiesToTotalAssets
Namespace Prefix:	atml_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant