Quarterly report pursuant to Section 13 or 15(d)

Segment Information - Summarized Segment Information (Detail)

v2.4.1.9
Segment Information - Summarized Segment Information (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Apr. 04, 2015
Mar. 29, 2014
Jan. 03, 2015
Segment Reporting Information [Line Items]      
Net sales $ 76,388us-gaap_SalesRevenueNet $ 68,028us-gaap_SalesRevenueNet  
Gross profit 21,478us-gaap_GrossProfit 20,701us-gaap_GrossProfit  
Operating costs 21,496us-gaap_OperatingExpenses [1] 20,206us-gaap_OperatingExpenses [1]  
Income (loss) from operations (18)us-gaap_OperatingIncomeLoss 495us-gaap_OperatingIncomeLoss  
Capital expenditures 2,151us-gaap_PaymentsToAcquirePropertyPlantAndEquipment 1,558us-gaap_PaymentsToAcquirePropertyPlantAndEquipment  
Depreciation and amortization expense 1,934us-gaap_DepreciationDepletionAndAmortization 2,368us-gaap_DepreciationDepletionAndAmortization  
Total assets, net of accumulated depreciation 83,839us-gaap_Assets 67,932us-gaap_Assets 82,907us-gaap_Assets
Base USAP      
Segment Reporting Information [Line Items]      
Net sales 76,325us-gaap_SalesRevenueNet
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		67,949us-gaap_SalesRevenueNet
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		 
Gross profit 21,415us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		20,622us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		 
Operating costs 20,720us-gaap_OperatingExpenses
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		[1] 19,645us-gaap_OperatingExpenses
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		[1]  
Income (loss) from operations 695us-gaap_OperatingIncomeLoss
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		977us-gaap_OperatingIncomeLoss
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		 
Capital expenditures 1,966us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		1,143us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		 
Depreciation and amortization expense 1,549us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		1,934us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		 
Total assets, net of accumulated depreciation 76,172us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		65,986us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember 		74,414us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_BaseUsapMember
AutoMD      
Segment Reporting Information [Line Items]      
Net sales 63us-gaap_SalesRevenueNet
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		79us-gaap_SalesRevenueNet
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		 
Gross profit 63us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		79us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		 
Operating costs 776us-gaap_OperatingExpenses
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		[1] 561us-gaap_OperatingExpenses
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		[1]  
Income (loss) from operations (713)us-gaap_OperatingIncomeLoss
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		(482)us-gaap_OperatingIncomeLoss
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		 
Capital expenditures 185us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		415us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		 
Depreciation and amortization expense 385us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		434us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		 
Total assets, net of accumulated depreciation $ 7,667us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		$ 1,946us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember 		$ 8,493us-gaap_Assets
/ us-gaap_StatementBusinessSegmentsAxis
= prts_AutoMdMember
[1] Operating costs for AutoMD primarily consist of depreciation and amortization on fixed assets and personnel costs. Indirect costs are not allocated to AutoMD.