Segment, Customer Concentration and Geographical Information - Wireless Revenues by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue from External Customer [Line Items]
Total revenues	$ 11,699	$ 16,443	$ 37,108	$ 43,743
Wireless
Revenue from External Customer [Line Items]
Total revenues	11,699	16,443	37,108	43,743
Wireless | Family Safety
Revenue from External Customer [Line Items]
Total revenues	9,625	11,969	30,153	29,355
Wireless | CommSuite
Revenue from External Customer [Line Items]
Total revenues	1,070	3,463	3,932	11,535
Wireless | ViewSpot
Revenue from External Customer [Line Items]
Total revenues	989	971	3,003	2,717
Wireless | Other
Revenue from External Customer [Line Items]
Total revenues	$ 15	$ 40	$ 20	$ 136