Operating Segment, Geographic Information and Significant Customers - Geographic Distribution of Revenues and Long Lived Assets from Continuing Operations (Detail) $ in Thousands	3 Months Ended
	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	1
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	$ 144,056	$ 106,069
Identifiable long-lived assets	50,829		$ 50,980
Components
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	40,400	32,812
Modules and Sub-assemblies
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	51,592	47,732
Integrated Subsystems
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	52,064	25,525
Total Sensor & Effector
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	78,691	74,297
Radar
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	40,979	36,540
Electronic Warfare
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	24,054	28,008
Other Sensor & Effector
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	13,658	9,749
C4I
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	44,224	12,825
Other End Applications
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	21,141	18,947
Domestic
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	130,579	89,678
International/Foreign Military Sales
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	13,477	16,391
US
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	131,349	97,715
Europe
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	11,438	7,478
Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	1,269	876
Reportable Geographical Components | US
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	132,996	99,462
Identifiable long-lived assets	46,919		47,997
Reportable Geographical Components | Europe
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	11,796	7,500
Identifiable long-lived assets	3,891		2,974
Reportable Geographical Components | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	1,269	876
Identifiable long-lived assets	19		9
Geography Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	(2,005)	(1,769)
Identifiable long-lived assets	0		$ 0
Geography Eliminations | US
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	1,647	1,747
Geography Eliminations | Europe
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	358	22
Geography Eliminations | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	$ 0	$ 0