Summary of Significant Accounting Policies - Additional Information (Detail)		3 Months Ended		12 Months Ended
	Dec. 02, 2020 USD ($)	Mar. 31, 2021 USD ($) Customer Vendor	Mar. 31, 2020 USD ($) Customer	Dec. 31, 2020 USD ($) Customer
Summary Of Significant Accounting Policies [Line Items]
Equity method investments		$ 0		$ 0
Guarantee or other funding obligations under equity method investment		302,277,000		301,430,000
Earnings or losses from equity method investment		0	$ 0
Revenue recognized from customer contracts		1,993,000
Remaining deferred revenues recognized			1,900,000
Note payable - related party		1,332,000		1,400,000
Revenues		61,935,000	$ 66,090,000
Inventories finished goods and purchased parts		22,279,000		23,529,000
Inventories raw materials		6,645,000		$ 6,458,000
impairment loss		6,656,000
Satellite Network [Member]
Summary Of Significant Accounting Policies [Line Items]
impairment loss		$ 6,656,000
Revenues [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of customers with revenues greater than 10% | Customer			0
Revenues [Member] | Customer Concentration Risk [Member] | Carrier Global Corporation [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		12.70%
Number of customers with revenues greater than 10% | Customer		1
Revenues [Member] | Customer Concentration Risk [Member] | Sanmina Corporation [Member] | Mexico [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		86.50%	85.70%
Number of vendors | Vendor		1
Revenues		$ 22,434,000	$ 21,992,000
Accounts Receivable | Carrier Global Corporation [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		11.80%		10.80%
Number of customers with accounts receivable greater than 12% | Customer		1		1
Senior Secured Notes [Member]
Summary Of Significant Accounting Policies [Line Items]
Senior secured notes principal amount	$ 220,000
Maximum [Member] | Revenues [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage			10.00%
ASU 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Warranty period		1 year
Estimated life of communicator		3 years
ASU 2014-09 [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Additional term of the agreement		2 years
ASU 2014-09 [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Additional term of the agreement		5 years
Equity Method Investment, Guarantee or Other Funding [Member]
Summary Of Significant Accounting Policies [Line Items]
Guarantee or other funding obligations under equity method investment		$ 0	$ 0