Number of directors.

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Number of employees.

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Unrecognized cost of unvested share-based compensation awards.

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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 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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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.

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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.

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The estimated measure of the maximum 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.

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The estimated measure of the minimum 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.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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No definition available.

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

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

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

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No definition available.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

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.

+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 718
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-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Percentage of vesting of share-based compensation awards.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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.

+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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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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Number of non-vested options outstanding.

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No definition available.

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Number of options vested.

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Value, before forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

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No definition available.

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The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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Stock-Based Compensation - Additional Information (Detail)			12 Months Ended
	Dec. 28, 2016 USD ($) shares	Nov. 15, 2016 shares	Dec. 27, 2017 shares	Dec. 28, 2016 USD ($) Director Employee $ / shares shares	Dec. 30, 2015 USD ($) Director shares	Dec. 31, 2014 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding	2,191,728			2,191,728	2,151,214	3,070,176
Common stock, options vested				1,746,501
Common stock, options unvested	445,227			445,227
Options to purchase common stock granted				347,053
Stock-based compensation expense \| $				$ 1,063,000	$ 539,000	$ 1,093,000
Aggregate intrinsic value of options outstanding \| $	$ 12,000,000			12,000,000
Aggregate intrinsic value of options exercisable \| $	11,400,000			11,400,000
Intrinsic value of options exercised \| $				900,000	14,900,000	11,500,000
Stock-based compensation expense \| $				900,000	$ 500,000	$ 1,100,000
Unrecognized compensation expense \| $	$ 1,200,000			$ 1,200,000
Unrecognized compensation expense, recognition period				2 years 10 months 24 days
Exercise price equal to the fair market value of the common stock on the date of grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options to purchase common stock granted				329,673	0
Option vesting period				4 years
Premium Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding	1,611,718			1,611,718
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted, percent						50.00%
Options granted, description				Of the total options granted in fiscal 2014, 50% were performance based and vested according to whether certain financial targets were met, and the remaining 50% vested over a term of four.
Authorized number of common stock for issuance, shares	4,402,240			4,402,240
Number of share available for grant	665,095			665,095
Weighted average grant date fair Value \| $ / shares				$ 4.13		$ 6.23
Expected volatility				32.40%
Expected life				5 years 9 months		5 years 9 months
Risk-free interest rates, Minimum				1.13%		1.70%
Risk-free interest rates, Maximum				1.76%		1.72%
Expected dividends				0.00%		0.00%
Expected volatility, Minimum						32.40%
Expected volatility, Maximum						41.00%
Performance Based Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding	0			0
Common stock, options vested	80,799	17,380
Stock-based compensation expense \| $				$ 600,000
Options expiration period				10 years
Performance Based Stock Options [Member] \| Scenario Forecast [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options vested			17,378
Time Based Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, options outstanding	2,191,728			2,191,728
Options expiration period				10 years
Restricted Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense \| $				$ 200,000	$ 100,000
Unrecognized compensation expense, recognition period				2 years 6 months
Number of directors granted shares \| Director				5	3
Number of employees granted shares \| Employee				2
Unrecognized compensation expense \| $	$ 500,000			$ 500,000
Restricted Shares [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense \| $						$ 100,000
Restricted Shares [Member] \| Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting period				3 years
Restricted shares granted					2,636
Value of restricted grants \| $				$ 50,000	$ 50,000
Restricted Shares [Member] \| Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting period				4 years
Restricted shares granted				5,178
Restricted Shares [Member] \| One and Two Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares granted				3,903
Restricted Shares [Member] \| Three, Four and Five Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares granted				3,699