Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013
Options
Beginning Balance	4,228
Granted	298
Exercised	(192)
Cancelled and expired	(8)
Ending Balance	4,326	4,228
Exercisable at June 30, 2013	3,493
Options vested and expected to vest at June 30, 2013	4,186
Weighted-Average Exercise Price
Beginning Balance	$ 11.49
Granted	$ 23.10
Exercised	$ 10.04
Cancelled and expired	$ 10.29
Ending Balance	$ 12.35	$ 11.49
Exercisable at June 30, 2013	$ 10.78
Options vested and expected to vest at June 30, 2013	$ 12.24
Weighted-Average Remaining Contractual Term (years)
Outstanding	5 years 6 months 4 days	5 years 4 months 13 days
Exercisable at June 30, 2013	4 years 8 months 19 days
Options vested and expected to vest at June 30, 2013	5 years 5 months 1 day
Aggregate Intrinsic Value
Outstanding at June 30, 2013	$ 40,584
Exercisable at June 30, 2013	37,729
Options vested and expected to vest at June 30, 2013	$ 39,701