Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016
Options
Outstanding at beginning of period	2,244
Granted	152
Exercised	(604)
Cancelled and expired	(14)
Outstanding at end of period	1,778	2,244
Exercisable at end of period	1,293
Options vested and expected to vest at end of period	1,726
Weighted-Average Exercise Price
Outstanding at beginning of period	$ 20.55
Granted	105.00
Exercised	13.66
Cancelled and expired	60.25
Outstanding at end of period	29.79	$ 20.55
Exercisable at end of period	17.82
Options vested and expected to vest at end of period	$ 28.92
Weighted-Average Remaining Contractual Term (years)
Outstanding	5 years 5 months 16 days	5 years 2 months 9 days
Exercisable at end of period	4 years 5 months 5 days
Options vested and expected to vest at end of period	5 years 4 months 17 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 147,680
Exercisable at end of period	122,671
Options vested and expected to vest at end of period	$ 144,841