Quarterly report pursuant to Section 13 or 15(d)

Net Income (Loss) Per Share - Anti-Dilutive Securities Excluded from Calculation of Diluted Earnings Per Share (Detail)

v2.4.1.9
Net Income (Loss) Per Share - Anti-Dilutive Securities Excluded from Calculation of Diluted Earnings Per Share (Detail)
In Thousands, unless otherwise specified
3 Months Ended
Apr. 04, 2015
Mar. 29, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from calculation of diluted earnings per share 10,817us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 7,588us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Common stock warrants    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from calculation of diluted earnings per share 50us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_WarrantMember
20us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_WarrantMember
Series A Convertible Preferred Stock    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from calculation of diluted earnings per share 4,150us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= prts_SeriesConvertiblePreferredStockMember
4,150us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= prts_SeriesConvertiblePreferredStockMember
Restricted stock units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from calculation of diluted earnings per share 905us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
0us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
Options to purchase common stock    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from calculation of diluted earnings per share 5,712us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember
3,418us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AwardTypeAxis
= us-gaap_StockOptionMember