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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-Publisher FASB

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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 share-based awards, other than options, awarded to employees as compensation.

+ References

No definition available.

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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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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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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Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Apr. 30, 2007
Limited Partners' Capital Account [Line Items]
Total fair value of other stock awards vested	$ 12
Employee Stock Purchase Plan [Member]
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	17	5
Stock Options [Member]
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	157	109
Unrecognized stock-based compensation expense	931
Unrecognized stock-based compensation expense, weighted average period	1 year 4 months 24 days
Restricted Stock and Restricted Stock Unit [Member]
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	3,667
Unrecognized stock-based compensation expense, weighted average period	2 years
Performance Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	2,483
Unrecognized stock-based compensation expense, weighted average period	1 month 6 days
Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 486	$ 461
Non-Employee Director [Member] \| Restricted Stock Awards [Member]
Limited Partners' Capital Account [Line Items]
Options vesting period	3 years
Minimum [Member] \| 2006 Stock Incentive Plan [Member]
Limited Partners' Capital Account [Line Items]
Options vesting period	1 year
Maximum [Member] \| 2006 Stock Incentive Plan [Member]
Limited Partners' Capital Account [Line Items]
Options vesting period	4 years
Options granted period	10 years
Class A Common Stock [Member] \| 2006 Stock Incentive Plan [Member]
Limited Partners' Capital Account [Line Items]
Common stock, issued shares			2,475,000
Number of shares available for future grant	495,000