Stock-Based Compensation Expense (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2017 USD ($) installment $ / shares shares	Mar. 31, 2016 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted (in shares) \| shares	75,000	50,000
Aggregate grant date fair value \| $	$ 100	$ 100
Number of vesting period anniversaries \| installment	4
Vesting stock based compensation related to awards \| $	$ 538	$ 878
Unrecognized stock-based compensation expense \| $	$ 2,300
Weighted average remaining life for recognition of unrecognized compensation expense	2 years 1 month 15 days
Stock options exercised during period (in shares) \| shares	0	0
Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting period anniversaries \| installment	2
Award vesting percentage	30.00%
Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting period anniversaries \| installment	2
Award vesting percentage	20.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (USD per share) \| $ / shares	$ 0.97
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (USD per share) \| $ / shares	$ 24.00

Share Based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Fair Value

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Number of Annual Award Vesting Installments

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
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- Definition

Unrecognized cost of unvested share-based compensation awards.

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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

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

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

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

Percentage of vesting of share-based compensation awards.

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- Definition

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

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