Accrued Liabilities - Summary of Accrued Warranty Obligations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Payables And Accruals [Abstract]
Balance at January 1,	$ 2,199	$ 2,762
Warranty liabilites assumed from acquisition	96
Amortization of fair value adjustment of warranty liabilities acquired through acquisitions	(19)	(9)
Reduction of warranty liabilities within the one-year measurement period assumed in connection with the acquisition of GlobalTrak	(250)
Warranty expense	60	65
Warranty charges	(196)	(291)
Balance at March 31,	$ 1,890	$ 2,527