Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 28, 2017	Jun. 29, 2016	Jun. 28, 2017	Jun. 29, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding (shares)	2,302,319		2,302,319
Common stock, options vested (shares)			1,835,285
Common stock, options unvested (shares)	467,034		467,034
Stock options exercised (shares)	17,661	115,340	17,661	115,340
Number of options granted at fair market value (shares)	128,252	319,798	128,252	319,798
Unrecognized compensation expense	$ 1,500		$ 1,500
Unrecognized compensation expense, recognition period			3 years 19 days
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	169,676	7,806	169,676	7,806
Stock-based compensation expense (less than $0.1 million in 2016)	$ 0	$ 0	$ 414	$ 139
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost	$ 100		$ 100
Premium Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding (shares)	1,563,549		1,563,549
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested restricted shares outstanding (shares)	194,387		194,387
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 2,500		$ 2,500
Unrecognized compensation expense, recognition period			3 years 7 months 14 days

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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- Definition

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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- Definition

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

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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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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- Definition

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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- Definition

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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- Definition

Number of non-vested options outstanding.

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- Definition

Number of options vested.

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- Definition

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

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