Summary of Significant Accounting Policies - Schedule of Estimated Economic Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Mar. 31, 2018
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of property and equipment	Shorter of 5 years or the life of lease
Furniture and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	5 years
Furniture and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	7 years
Computer Hardware [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	2 years
Computer Hardware [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	5 years
Computer Software Property and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	3 years
Computer Software Property and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	5 years