Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v2.4.1.9
Income Taxes - Additional Information (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended 0 Months Ended
Jan. 03, 2015
Dec. 28, 2013
Dec. 29, 2012
Oct. 08, 2014
Income Taxes [Line Items]        
Effective tax rate (2.00%)us-gaap_EffectiveIncomeTaxRateContinuingOperations (0.30%)us-gaap_EffectiveIncomeTaxRateContinuingOperations 2.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations  
Change in valuation allowance $ 2,366us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance $ 6,621us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance $ 14,080us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance  
Annual usage limitation 135prts_AnnualUsageLimitationOfOperatingLossCarryForwards      
Amount of tax benefit of the federal and state NOL carryforwards which was created by the exercise of stock options 41us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation      
Accrued expenses related to income taxes payable 33us-gaap_AccruedIncomeTaxes 26us-gaap_AccruedIncomeTaxes    
Deferred tax liability as a result of transaction 1,335us-gaap_DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates 0us-gaap_DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates    
Valuation allowance 45,867us-gaap_DeferredTaxAssetsValuationAllowance 43,509us-gaap_DeferredTaxAssetsValuationAllowance    
Federal        
Income Taxes [Line Items]        
Net operating loss carryforwards 57,552us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember
     
NOL carryforwards expire date 2029      
State        
Income Taxes [Line Items]        
Net operating loss carryforwards 73,610us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember
     
NOL carryforwards expire date 2015      
Whitney Automotive Group (WAG) | Federal        
Income Taxes [Line Items]        
Net operating loss carryforwards 2,690us-gaap_OperatingLossCarryforwards
/ us-gaap_BusinessAcquisitionAxis
= prts_WhitneyAutomotiveGroupMember
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember
     
AutoMD        
Income Taxes [Line Items]        
Effective tax rate (0.20%)us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
     
Common stock issued       7,000,000us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
Percentage ownership after issuance of shares       64.10%us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
Deferred tax liability as a result of transaction 1,335us-gaap_DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
     
Valuation allowance 195us-gaap_DeferredTaxAssetsValuationAllowance
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
     
AutoMD | Federal        
Income Taxes [Line Items]        
Net operating loss carryforwards $ 2,582us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember