Summary of Restructuring Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			$ 1,179	$ 1,591	$ 441
Restructuring costs	$ 200	$ 1,700		192	1,731
Cash payments			(186)	(476)	(441)
Other				(128)	(140)
Restructuring Reserve, Ending Balance		1,591	993	1,179	1,591
Personnel and Facilities | Antenna Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			1,179	1,591
Restructuring costs				192	1,731
Cash payments			(186)	(476)
Other				(128)	(140)
Restructuring Reserve, Ending Balance		$ 1,591	$ 993	$ 1,179	$ 1,591