Summary of Significant Accounting Principles - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2015 USD ($) Customer	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2015 USD ($) Customer	Dec. 31, 2015 USD ($) Customer
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		0	0
Inventories finished goods and purchased parts		$ 13,682,000		$ 13,682,000		16,912,000
Inventories raw materials		8,036,000		8,036,000		$ 3,800,000
Impairment loss - satellite network		10,680,000		$ 10,680,000	$ 12,748,000
Warranty period				1 year
OG2 Satellite Impairment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment loss - satellite network	$ 12,748,000	$ 10,680,000
Hub City Terminals Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers with revenues greater than 10% | Customer			1
Caterpillar Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers with accounts receivable greater than 10% | Customer				1		1
Sales [Member] | Customer Concentration Risk [Member] | Hub City Terminals Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage			11.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Caterpillar Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage				10.70%		11.60%