Accounting Policies - Schedule of Revenues on Disaggregated Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenues	$ 6,945	$ 5,862	$ 12,408	$ 11,438
Wireless [Member]
Disaggregation Of Revenue [Line Items]
Revenues	6,506	4,629	11,322	8,988
Wireless [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Revenues	262	72	262	72
Wireless [Member] | Platform [Member]
Disaggregation Of Revenue [Line Items]
Revenues	5,646	3,653	9,873	7,254
Wireless [Member] | Services [Member]
Disaggregation Of Revenue [Line Items]
Revenues	572	671	1,066	1,361
Wireless [Member] | Contract [Member]
Disaggregation Of Revenue [Line Items]
Revenues	26	233	121	301
Graphics [Member]
Disaggregation Of Revenue [Line Items]
Revenues	439	1,233	1,086	2,450
Graphics [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 439	$ 1,233	$ 1,086	$ 2,450