Segment, Customer Concentration and Geographical Information - Wireless Revenues by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue from External Customer [Line Items]
Total revenues	$ 12,629	$ 11,782	$ 38,883	$ 31,068
Wireless [Member]
Revenue from External Customer [Line Items]
Total revenues	12,509	11,614	38,424	30,422
Wireless [Member] | SafePath [Member]
Revenue from External Customer [Line Items]
Total revenues	6,755	5,200	21,948	11,108
Wireless [Member] | CommSuite [Member]
Revenue from External Customer [Line Items]
Total revenues	4,542	4,602	13,411	13,957
Wireless [Member] | ViewSpot [Member]
Revenue from External Customer [Line Items]
Total revenues	1,157	1,260	2,873	3,673
Wireless [Member] | Netwise [Member]
Revenue from External Customer [Line Items]
Total revenues	33	493	118	1,492
Wireless [Member] | Other [Member]
Revenue from External Customer [Line Items]
Total revenues	$ 22	$ 59	$ 74	$ 192