Segment, Customer Concentration and Geographical Information - Wireless Revenues by Product (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue from External Customer [Line Items]
Total revenues	$ 12,735	$ 11,381
Wireless [Member]
Revenue from External Customer [Line Items]
Total revenues	12,735	11,381
Wireless [Member] | SafePath [Member]
Revenue from External Customer [Line Items]
Total revenues	10,366	6,267
Wireless [Member] | CommSuite [Member]
Revenue from External Customer [Line Items]
Total revenues	1,429	4,128
Wireless [Member] | ViewSpot [Member]
Revenue from External Customer [Line Items]
Total revenues	935	930
Wireless [Member] | Other [Member]
Revenue from External Customer [Line Items]
Total revenues	$ 5	$ 56