v2.4.1.9
ACQUIRED INTANGIBLE ASSETS, NET (Schedule of Acquired Intangible Assets) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]    
Intangible assets, gross $ 31,808us-gaap_FiniteLivedIntangibleAssetsGross $ 27,287us-gaap_FiniteLivedIntangibleAssetsGross
Less: Accumulated amortization (14,529)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization (15,069)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Impairment loss recognized (820)acts_ImpairmentOfIntangibleAssetFiniteLived   
IPR&D not subject to amortization 420us-gaap_OtherIndefiniteLivedIntangibleAssets 420us-gaap_OtherIndefiniteLivedIntangibleAssets
Less: Impairment loss in respect of IPR&D recognized (420)acts_ImpairmentOfIntangibleAssetsIndefiniteLived (420)acts_ImpairmentOfIntangibleAssetsIndefiniteLived
Acquired intangible assets, net 16,459us-gaap_IntangibleAssetsNetExcludingGoodwill 12,218us-gaap_IntangibleAssetsNetExcludingGoodwill
Purchased software [Member]    
Finite-Lived Intangible Assets [Line Items]    
Intangible assets, gross 8,654us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_ComputerSoftwareIntangibleAssetMember
9,647us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_ComputerSoftwareIntangibleAssetMember
Less: Accumulated amortization (6,961)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_ComputerSoftwareIntangibleAssetMember
(7,054)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_ComputerSoftwareIntangibleAssetMember
Impairment loss recognized (168)acts_ImpairmentOfIntangibleAssetFiniteLived
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_ComputerSoftwareIntangibleAssetMember
  
Technology licenses [Member]    
Finite-Lived Intangible Assets [Line Items]    
Intangible assets, gross 23,154us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_LicensingAgreementsMember
17,640us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_LicensingAgreementsMember
Less: Accumulated amortization (7,568)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_LicensingAgreementsMember
(8,015)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_LicensingAgreementsMember
Impairment loss recognized $ (652)acts_ImpairmentOfIntangibleAssetFiniteLived
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_LicensingAgreementsMember