Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Mar. 09, 2018	Jul. 01, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	U.S. Auto Parts Network, Inc.
Entity Central Index Key	0001378950
Current Fiscal Year End Date	--12-30
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	PRTS
Amendment Flag	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		34,858,147
Entity Public Float			$ 91.4