Acquisition - Additional Information (Detail) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013	Oct. 09, 2013 Antenna	Mar. 31, 2014 Antenna
Business Acquisition [Line Items]
Purchase price of acquired company	$ 793,000				$ 27,100,000	$ 27,141,000
Cash purchase price deposited in escrow					4,200,000
Acquisition-related costs	206,000					200,000
Revenue since acquisition date						4,700,000
Net earnings(loss) since acquisition date						(2,200,000)
Purchase price adjustment against goodwill	(594,000)	[1]				600,000
Goodwill	36,869,000			36,869,000		16,418,000
Deferred tax assets						36,700,000
Defered tax assets, valuation allowance						24,200,000
Deferred tax liability						6,900,000
Deferred tax assets, net						5,600,000
Amortization expense of acquired intangibles assets	$ 3,756,000		$ 2,777,000			$ 10,400,000

[1] The purchase price adjustments identified during the first quarter of 2014 have been retroactively applied as of December 31, 2013.