Revenues - Schedule of Revenues on Disaggregated Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 11,381	$ 13,322
Wireless [Member]
Disaggregation Of Revenue [Line Items]
Revenues	11,381	13,215
Wireless [Member] | License and Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenues	1,587	555
Wireless [Member] | Hosted Environment Usage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenues	4,141	4,549
Wireless [Member] | Cloud Based Usage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenues	4,963	7,647
Wireless [Member] | Consulting Services and Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 690	$ 571