Document and Entity Information - shares	6 Months Ended
	Jul. 04, 2015	Aug. 05, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Jul. 04, 2015
Amendment Flag	false
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	PRTS
Entity Registrant Name	U.S. Auto Parts Network, Inc.
Entity Central Index Key	0001378950
Current Fiscal Year End Date	--01-02
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		34,001,972