Commitments and Contingencies - Additional Information (Detail) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 07, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Employee	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Restructuring and related activities, initiation date	Aug. 07, 2019
Restructuring and related charges, description				The severance payments for these employees were paid during the second and third quarters of 2020
Restructuring expenses	$ 600	$ 25	$ 295	$ 124	$ 295
Number of employees | Employee				12
Refund liability related to estimated sales returns		109		$ 109		$ 147
Warranties		250		250		444
Warranty Reserves [Member]
Commitments And Contingencies Disclosure [Line Items]
Refund liability related to estimated sales returns		100		100		100
Warranties		$ 250	$ 400	$ 250	$ 400	$ 444	$ 339
Warranty Reserves [Member] | Antenna [Member]
Commitments And Contingencies Disclosure [Line Items]
Repair and replacement warranty				5 years
Tianjin [Member]
Commitments And Contingencies Disclosure [Line Items]
Number of employees | Employee				96
Colorado Office [Member]
Commitments And Contingencies Disclosure [Line Items]
Lease expiration month and year				2020-10