Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, beginning balance	$ 2,647	$ 12,490	$ 19,967
Amortization of intangibles	(1,416)	(7,087)	(7,477)
Adjustment/writeoff		(2,756)
Intangible assets, ending balance	$ 1,231	$ 2,647	$ 12,490