Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity and Share-Based Compensation - Restricted Stock Units (Details)

v2.4.1.9
Stockholders' Equity and Share-Based Compensation - Restricted Stock Units (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Jan. 03, 2015
Aug. 01, 2014
Apr. 03, 2014
Feb. 14, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period of unrecognized compensation expense 2 years 7 months 28 days      
Restricted Stock Units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Awards granted 1,015,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
     
Closing price of grant (in dollars per share)   $ 3.17us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
$ 2.93us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
$ 2.03us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
Awards forfeited 171,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
     
Compensation expense $ 1,345us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
     
Unrecognized compensation expense $ 757us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
     
Weighted-average period of unrecognized compensation expense 10 months 12 days      
Time-Based RSU Award        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Awards granted 738,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= prts_TimeBasedRestrictedStockUnitMember
     
Performance-based RSU Award        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Awards granted 277,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= prts_PerformanceBasedRestrictedStockUnitMember
     
Awards forfeited 106,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= prts_PerformanceBasedRestrictedStockUnitMember