Business Segments - Schedule of Revenues by Major Customers (Detail) - Total revenue - Customer concentration risk	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
INOX Wind Limited
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for YMC Inc. for the six months ended September 2017)	46.00%	68.00%	35.00%	51.00%
Navy Surface Warfare Center Carderock [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for YMC Inc. for the six months ended September 2017)	0.00%	0.00%	16.00%	0.00%
YMC, Inc.
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for YMC Inc. for the six months ended September 2017)	15.00%	0.00%		0.00%