Consolidated Balance Sheet Detail - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Property Plant And Equipment [Line Items]
Total property and equipment	$ 95,516	$ 78,426
Less: accumulated depreciation	(20,625)	(14,896)
Total property and equipment, net	74,891	63,530
Land [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	1,254	1,286
Plant and Equipment [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	49,368	44,797
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Total property and equipment	$ 44,894	$ 32,343