Proceeds received from the sale of product line

No definition available.

Name:	atml_DisposalOfProductLineSaleProceeds
Namespace Prefix:	atml_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fee associated with disposal of property plant and equipment

+ References

No definition available.

+ Details

Name:	atml_Feeassociatedwithdisposalofpropertyplantandequipment
Namespace Prefix:	atml_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate value (measured at the lower of net carrying value or fair value less cost of disposal) for current assets (assets with expected useful life shorter than one year or one operating cycle, whichever is longer) of a disposal group, including a component of the entity (discontinued operation), to be sold or that has subsequently been disposed of through sale, as of the financial statement date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759

+ Details

Name:	us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 40

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.U.Q2)

-URI http://asc.fasb.org/extlink&oid=6955272&loc=d3e221323-122791

+ Details

Name:	us-gaap_DeferredGainOnSaleOfProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest income earned from interest bearing assets not separately disclosed.

+ References

No definition available.

+ Details

Name:	us-gaap_InterestIncomeOther
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=atml_NorthTynesideMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SALE OF ASSETS (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
SALE OF ASSETS (Narrative) (Details) (USD $)	Sep. 28, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Gains) losses on sale of assets, net		$ 4,364,000	$ 886,000	$ (264,000)
Fee associated with disposal of property plant and equipment		500,000
Interest Income, Other		1,300,000us-gaap_InterestIncomeOther
Disposal of Product Line Sale Proceeds	25,000,000atml_DisposalOfProductLineSaleProceeds
Assets of Disposal Group, Including Discontinued Operation, Current					7,000,000
Deferred Gain on Sale of Property			$ 4,400,000us-gaap_DeferredGainOnSaleOfProperty
North Tyneside [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity Method Investment, Ownership Percentage		50.20%