Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Land	$ 4,474	$ 4,046
Building and building improvements	13,669	10,900
Capital lease asset	16,784	16,784
Leasehold improvements	37,292	34,854
Machinery and equipment	33,677	27,989
Furniture and fixtures	7,578	3,899
Construction in progress	10,458	9,257
Total cost	123,932	107,729
Less accumulated depreciation	(26,235)	(19,952)
Property and equipment, net	$ 97,697	$ 87,777