Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017
Options
Outstanding at beginning of period	1,646
Granted	123
Exercised	(223)
Cancelled and expired	(22)
Outstanding at end of period	1,524	1,646
Exercisable at end of period	1,147
Options vested and expected to vest at end of period	1,487
Weighted-Average Exercise Price
Outstanding at beginning of period	$ 32.09
Granted	134.24
Exercised	15.92
Cancelled and expired	109.07
Outstanding at end of period	41.62	$ 32.09
Exercisable at end of period	22.95
Options vested and expected to vest at end of period	$ 40.93
Weighted-Average Remaining Contractual Term (years)
Outstanding	5 years 9 months 11 days	5 years 5 months 16 days
Exercisable at end of period	4 years 9 months 3 days
Options vested and expected to vest at end of period	5 years 8 months 19 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 154,937
Exercisable at end of period	138,019
Options vested and expected to vest at end of period	$ 152,210