Status of Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Shares
Outstanding	4,249,168	3,708,773
Vested and expected to vest	4,106,671
Vested	2,503,676
Weighted-Average Exercise Price Per Share
Outstanding	$ 14.77	$ 9.43
Vested and expected to vest	$ 14.47
Vested	$ 9.67
Remaining Contractual Life
Outstanding	6 years 7 months 6 days
Vested and expected to vest	6 years 7 months 6 days
Vested	5 years 2 months 12 days
Aggregate Intrinsic Value
Outstanding	$ 57,709
Vested and expected to vest	57,009
Vested	$ 46,722

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Share based compensation arrangement by share based payment award options vested weighted average exercise Price.

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Share based compensation arrangement by share based payment award options vested weighted average remaining contractual life.

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

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Number of options outstanding, including both vested and non-vested options.

+ References

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-Publisher FASB

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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 remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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Weighted average remaining contractual term for fully vested and expected to vest options that are 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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Number of options vested.

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