Stockholders' Equity - Stock Options Outstanding, Exercisable and Expected to Vest (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Stock options outstanding, exercisable and expected to vest
Options outstanding, Number of Shares	844,898	857,311	470,985
Options outstanding, Weighted Average Exercise Price	$ 8.84	$ 9.49	$ 8.69
Options outstanding, Weighted Average Remaining Contractual Life (years)	4 years 7 months 9 days
Options outstanding, Aggregate Intrinsic Value	$ 12
Options vested and expected to vest, Number of Shares	797,921
Options vested and expected to vest, Weighted Average Exercise Price	$ 8.87
Options vested and expected to vest, Weighted Average Remaining Contractual Life (years)	4 years 6 months 10 days
Options vested and expected to vest, Aggregate Intrinsic Value	$ 12
Options exercisable, Number of Shares	418,316
Options exercisable, Weighted Average Exercise Price	$ 9.12
Options exercisable, Weighted Average Remaining Contractual Life (years)	3 years 4 months 17 days
Options exercisable, Aggregate Intrinsic Value	$ 12

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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