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Stockholders' Equity and Share-Based Compensation - Summary of Assumptions Used for Fair Value of Surrendered Stock Options and New Stock Options (Detail)
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12 Months Ended |
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Jan. 03, 2015
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| Surrendered Stock Options | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Expected dividend yield |
0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate / us-gaap_AwardTypeAxis = prts_SurrenderedStockOptionsMember |
| Surrendered Stock Options | Minimum | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Expected life | 1 year 11 months 4 days |
| Risk-free interest rate |
0.50%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_SurrenderedStockOptionsMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
| Expected volatility |
55.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_SurrenderedStockOptionsMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
| Surrendered Stock Options | Maximum | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Expected life | 6 years 10 months 13 days |
| Risk-free interest rate |
2.40%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_SurrenderedStockOptionsMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
| Expected volatility |
73.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_SurrenderedStockOptionsMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
| New Stock Options | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Expected life | 5 years 10 months 2 days |
| Risk-free interest rate |
2.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate / us-gaap_AwardTypeAxis = prts_NewStockOptionsMember |
| Expected volatility |
72.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate / us-gaap_AwardTypeAxis = prts_NewStockOptionsMember |
| Expected dividend yield |
0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate / us-gaap_AwardTypeAxis = prts_NewStockOptionsMember |
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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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- 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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- 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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- 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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