Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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

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Percentage of vesting of share-based compensation awards.

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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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Officers' Compensation, Annual Salary

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Officers' Compensation, Cash Bonus Eligibility, Percent Of Base Salary

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Chief Executive Officer Transition (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Jan. 03, 2018	Nov. 30, 2017	Dec. 31, 2016	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common shares (in shares)				1,405,054
Option term			5 years 8 months 12 days
Exercise price (in usd per share)				$ 7.94
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance costs				$ 525
Stock-based compensation expense				$ 674
Percent vesting monthly for the three years following first anniversary of start date \| Amended and Restated 2017 Inducement Equity Incentive Plan \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		2.00%
Subsequent Event \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Base salary	$ 540
Cash signing bonus	$ 330
Percent of base salary eligible for cash bonus annually	50.00%
Subsequent Event \| Amended and Restated 2017 Inducement Equity Incentive Plan \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common shares (in shares)	1,588,832
Option term	10 years
Exercise price (in usd per share)	$ 6.30
Vesting period	4 years
Subsequent Event \| Percent vesting one year from start date \| Amended and Restated 2017 Inducement Equity Incentive Plan \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%