Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 28, 2018	Mar. 29, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding (shares)	2,225,251
Common stock, options vested (shares)	1,909,440
Common stock, options unvested (shares)	315,811
Stock options exercised (shares)	0	0
Number of options granted at fair market value (shares)	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	0	0
Stock-based compensation	$ 531	$ 141
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost	$ 500
Premium Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding (shares)	1,599,944
Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense	$ 900
Unrecognized compensation expense, recognition period	2 years 5 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting, Number	33,545
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense, recognition period	2 years 11 months 2 days
Unvested restricted shares outstanding (shares)	170,830
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 1,800

Unrecognized cost of unvested share-based compensation awards.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Net number of non-option equity instruments granted to participants.

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Gross number of share options (or share units) granted during the period.

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

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An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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Number of shares for which recognition of compensation cost was accelerated.

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- Definition

Number of non-vested options outstanding.

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Number of options vested.

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Number of share options (or share units) exercised during the current period.

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