Operating Segment, Geographic Information and Significant Customers - Customers Comprising Ten Percent or more Revenues (Detail) - Sales Revenue, Net	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Revenue, Major Customer [Line Items]
Concentration risk, percentage	0.00%	18.00%	0.00%	0.00%
Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	38.00%	41.00%	48.00%	39.00%
Customer Concentration Risk | Lockheed Martin Corporation
Revenue, Major Customer [Line Items]
Concentration risk, percentage	21.00%	14.00%	19.00%	17.00%
Customer Concentration Risk | Lockheed Martin Corporation [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	17.00%	27.00%	19.00%	22.00%
Customer Concentration Risk | Northrop Grumman Corporation
Revenue, Major Customer [Line Items]
Concentration risk, percentage			10.00%