Operating Segment, Geographic Information and Significant Customers - Customers Comprising Ten Percent or more Revenues (Detail) - Sales Revenue, Net	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Revenue, Major Customer [Line Items]
Concentration risk, percentage	0.00%	11.00%	0.00%	10.00%
Customer Concentration Risk
Revenue, Major Customer [Line Items]
Concentration risk, percentage	49.00%	45.00%	49.00%	38.00%
Customer Concentration Risk | Lockheed Martin Corporation
Revenue, Major Customer [Line Items]
Concentration risk, percentage	20.00%	13.00%	19.00%	19.00%
Customer Concentration Risk | Raytheon Company
Revenue, Major Customer [Line Items]
Concentration risk, percentage	17.00%	22.00%	19.00%	19.00%
Customer Concentration Risk | Northrop Grumman Corporation
Revenue, Major Customer [Line Items]
Concentration risk, percentage	12.00%	10.00%	11.00%