XML 34 R71.htm IDEA: XBRL DOCUMENT v2.4.1.9
Income Taxes - Reconciliation of Change in Federal and State Unrecognized Tax Benefits (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Income Tax Disclosure [Abstract]      
Balance at the beginning of the year $ 1,982us-gaap_UnrecognizedTaxBenefits    
Increases (decreases) for prior year tax positions 1,982us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions 1,982us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions  
Increases (decreases) for current year tax positions 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreaseResultingFromCurrentPeriodTaxPositions 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreaseResultingFromCurrentPeriodTaxPositions 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreaseResultingFromCurrentPeriodTaxPositions
Increases (decreases) related to settlements 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreasesRelatedToSettlements 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreasesRelatedToSettlements 0atrc_UnrecognizedTaxBenefitsIncreasesOrDecreasesRelatedToSettlements
Decreases related to statute lapse 0us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations 0us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations 0us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Balance at the end of the year $ 1,982us-gaap_UnrecognizedTaxBenefits $ 1,982us-gaap_UnrecognizedTaxBenefits