Option Activity and Changes (Detail)	9 Months Ended
Sep. 29, 2018 $ / shares shares
Shares
Options outstanding at December 30, 2017 \| shares	2,925,861
Options granted \| shares	421,125
Options cancelled and forfeited \| shares	(936,428)
Options exercised \| shares	(321,190)
Options outstanding at September 29, 2018 \| shares	2,089,368
Options exercisable at September 29, 2018 \| shares	1,331,565
Weighted Average Exercise Price
Options outstanding at December 30, 2017 \| $ / shares	$ 7.62
Options granted \| $ / shares	5.13
Options cancelled and forfeited \| $ / shares	9.31
Options exercised \| $ / shares	4.87
Options outstanding at September 29, 2018 \| $ / shares	6.78
Options exercisable at September 29, 2018 \| $ / shares	$ 6.60

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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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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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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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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

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