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Stockholders' Equity and Share-Based Compensation - Summary of Assumptions Used for Fair Value of Option Grant (Detail) (Option Grant)
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12 Months Ended | ||
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Jan. 03, 2015
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Dec. 28, 2013
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Dec. 29, 2012
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected life | 5 years 8 months 23 days | ||
| Risk-free interest rate | 1.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate | ||
| Expected dividend yield | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate | 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate |
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Minimum
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected life | 5 years 3 months 18 days | 5 years 2 months 15 days | |
| Risk-free interest rate |
2.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
1.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
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| Expected volatility |
62.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
67.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
71.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
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Maximum
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected life | 5 years 4 months 13 days | 5 years 8 months 23 days | |
| Risk-free interest rate |
2.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
2.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
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| Expected volatility |
68.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
73.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
74.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_OptionGrantMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
| X | ||||||||||
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- Definition
The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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