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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(ii)
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- Definition

Unrecognized cost of unvested share-based compensation awards.

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-Publisher FASB
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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

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Amount of cash inflow from issuance of shares under share-based compensation arrangement, excluding stock option exercises.

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- Definition

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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- 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

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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No definition available.

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

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Stock Incentive Plans - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2018	Jun. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 700,000
Share-based compensation expense, tax benefit recognized	0
Share-based compensation costs, capitalized	0
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate proceeds from the issuance of shares		$ 100,000	$ 100,000
Shares issued under ESPP		52,612	34,176
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of RSUs	800,000
Total unrecognized compensation costs related to stock options and RSUs	$ 1,600,000
Stock options and RSUs expected weighted average period	2 years 2 months 1 day
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs related to stock options and RSUs	$ 1,900,000
Stock options and RSUs expected weighted average period	6 years 10 months 6 days
Intrinsic value of options	$ 3,200,000