Stock Option Plans - Activity of Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, shares	1,203,990
Granted, shares	66,690
Forfeited, shares	(169,936)
Exercised, shares	(186,919)
Ending balance, shares	913,825
Beginning balance, weighted average exercise price	$ 13.26
Granted, Weighted-Average Exercise Price	$ 41.80
Forfeited, Weighted-Average Exercise Price	$ 25.78
Exercised, Weighted Average Exercise Price	$ 10.48
Ending Balance, Weighted-Average Exercise Price	$ 13.58
Vested and expected to vest, Shares	779,907
Vested and expected to vest, Weighted Average Exercise Price	$ 11.09
Vested and expected to vest, Weighted Average Remaining Contractual Term	3 years 10 months 24 days
Vested and expected to vest, Aggregate Intrinsic Value	$ 22,692
Exercisable, Shares	674,565
Exercisable, Weighted Average Exercise Price	$ 8.87
Exercisable, Weighted Average Remaining Contractual Term	3 years 2 months 12 days
Exercisable, Intrinsic Value	$ 21,128

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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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.

+ References

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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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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

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Weighted average price of options that were either forfeited or expired.

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-Publisher FASB

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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

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

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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-Publisher FASB

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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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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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- Definition

As of the balance sheet date, the weighted-average exercise price for outstanding 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 outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

+ References

No definition available.

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

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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