Fair Value Measurements (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 30, 2013	Mar. 31, 2012
Fair Value Measurements (Textual) [Abstract]
Transfers into or out of level 1 and level 2 assets	$ 0	$ 0
Original maturity of money market funds and short-term investments purchased	90 days

Cash equivalents money market funds and short term investments maturity period.

No definition available.

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Namespace Prefix:	prts_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration