Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015
Options
Outstanding at beginning of period	2,892
Granted	164
Exercised	(721)
Cancelled and expired	(2)
Outstanding at end of period	2,333	2,892
Exercisable at end of period	1,690
Options vested and expected to vest at end of period	2,273
Weighted-Average Exercise Price
Outstanding at beginning of period	$ 14.72
Granted	71.15
Exercised	11.42
Cancelled and expired	13.81
Outstanding at end of period	19.71	$ 14.72
Exercisable at end of period	13.83
Options vested and expected to vest at end of period	$ 19.33
Weighted-Average Remaining Contractual Term (years)
Outstanding	5 years 4 months 6 days	5 years 2 months 5 days
Exercisable at end of period	4 years 3 months 7 days
Options vested and expected to vest at end of period	5 years 3 months 7 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 164,775
Exercisable at end of period	129,224
Options vested and expected to vest at end of period	$ 161,336