Summary of Significant Accounting Principles - Additional Information (Detail)	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Customer	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Equity method investments	$ 0			$ 0		$ 0
Guarantee or other funding obligations under equity method investment	0			0
Losses from equity method investment	$ 0		$ 0	$ 0	$ 0
Number of customers with revenues greater than 10% | Customer				0
Impairment loss - satellite network		$ 12,748,000		$ 12,748,000
Typical warranty coverage period on product sales				1 year
Sales [Member] | Customer Concentration Risk [Member] | Hub City Terminals, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Customers with revenues greater than 10%	11.00%
Sales [Member] | Customer Concentration Risk [Member] | Caterpillar Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Customers with revenues greater than 10%			13.50%		13.30%
Sales [Member] | Customer Concentration Risk [Member] | Komatsu Ltd. [Member]
Summary Of Significant Accounting Policies [Line Items]
Customers with revenues greater than 10%			11.60%		11.30%