Segment, Customer Concentration and Geographical Information - Wireless Revenues by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue from External Customer [Line Items]
Total revenues	$ 12,674	$ 15,919	$ 25,409	$ 27,300
Wireless
Revenue from External Customer [Line Items]
Total revenues	12,674	15,919	25,409	27,300
Wireless | Family Safety
Revenue from External Customer [Line Items]
Total revenues	10,161	11,119	20,528	17,385
Wireless | CommSuite
Revenue from External Customer [Line Items]
Total revenues	1,433	3,944	2,862	8,073
Wireless | ViewSpot
Revenue from External Customer [Line Items]
Total revenues	1,080	817	2,014	1,746
Wireless | Other
Revenue from External Customer [Line Items]
Total revenues	$ 0	$ 39	$ 5	$ 96