Segment, Customer and Geographic Information - Continuing Operations - Result of Operations by Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Results of operations by segments
REVENUES	$ 23,665	$ 20,892	$ 68,136	$ 61,383
GROSS PROFIT	10,150	8,255	28,566	24,648
OPERATING INCOME (LOSS) FOR CONTINUING OPERATIONS	893	(300)	578	(1,675)
Depreciation	651	674	1,913	1,994
Intangible amortization	291	291	872	908
Capital expenditures	553	282	2,097	1,550
Operating Segments [Member] | Connected Solutions [Member]
Results of operations by segments
REVENUES	17,988	17,136	52,125	47,616
GROSS PROFIT	6,148	5,771	17,283	15,035
OPERATING INCOME (LOSS) FOR CONTINUING OPERATIONS	2,684	2,530	6,775	5,625
Depreciation	437	484	1,288	1,417
Intangible amortization	39	39	117	153
Capital expenditures	437	284	1,294	1,127
Operating Segments [Member] | RF Solutions [Member]
Results of operations by segments
REVENUES	5,739	3,814	16,157	13,931
GROSS PROFIT	4,006	2,497	11,275	9,620
OPERATING INCOME (LOSS) FOR CONTINUING OPERATIONS	883	(467)	2,319	344
Depreciation	140	190	419	577
Intangible amortization	252	252	755	755
Capital expenditures	103	16	388	90
Corporate, Non-Segment [Member]
Results of operations by segments
REVENUES	(62)	(58)	(146)	(164)
GROSS PROFIT	(4)	(13)	8	(7)
OPERATING INCOME (LOSS) FOR CONTINUING OPERATIONS	(2,674)	(2,363)	(8,516)	(7,644)
Depreciation	74	0	206	0
Intangible amortization	0	0	0	0
Capital expenditures	$ 13	$ (18)	$ 415	$ 333