Annual report pursuant to Section 13 and 15(d)

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail)

v2.4.1.9
Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Jan. 03, 2015
Sep. 27, 2014
Jun. 28, 2014
Mar. 29, 2014
Dec. 28, 2013
Sep. 28, 2013
Jun. 29, 2013
Mar. 30, 2013
Jan. 03, 2015
Dec. 28, 2013
Dec. 29, 2012
Numerator:                      
Net loss attributable to U.S. Auto Parts stockholders' $ (2,406)us-gaap_NetIncomeLoss $ (2,494)us-gaap_NetIncomeLoss $ (2,180)us-gaap_NetIncomeLoss $ 201us-gaap_NetIncomeLoss $ (1,325)us-gaap_NetIncomeLoss $ (1,399)us-gaap_NetIncomeLoss $ (9,567)us-gaap_NetIncomeLoss $ (3,343)us-gaap_NetIncomeLoss $ (6,879)us-gaap_NetIncomeLoss $ (15,634)us-gaap_NetIncomeLoss $ (35,978)us-gaap_NetIncomeLoss
Dividends on Series A Convertible Preferred Stock                 (240)us-gaap_PreferredStockDividendsIncomeStatementImpact (184)us-gaap_PreferredStockDividendsIncomeStatementImpact 0us-gaap_PreferredStockDividendsIncomeStatementImpact
Net loss available to common shares                 $ (7,119)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic $ (15,818)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic $ (35,978)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Denominator:                      
Weighted-average common shares outstanding (basic and diluted) (in shares)                 33,489us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted 32,697us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted 30,818us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted
Basic and diluted net loss per share (in dollars per share) $ (0.07)us-gaap_EarningsPerShareBasicAndDiluted $ (0.08)us-gaap_EarningsPerShareBasicAndDiluted $ (0.07)us-gaap_EarningsPerShareBasicAndDiluted $ 0.00us-gaap_EarningsPerShareBasicAndDiluted $ (0.04)us-gaap_EarningsPerShareBasicAndDiluted $ (0.04)us-gaap_EarningsPerShareBasicAndDiluted $ (0.29)us-gaap_EarningsPerShareBasicAndDiluted $ (0.11)us-gaap_EarningsPerShareBasicAndDiluted $ (0.21)us-gaap_EarningsPerShareBasicAndDiluted $ (0.48)us-gaap_EarningsPerShareBasicAndDiluted $ (1.17)us-gaap_EarningsPerShareBasicAndDiluted