Summary of Intangible Assets (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Gross Carrying Amount		$ 8,361	$ 6,161
Total intangible assets, Accumulated Amortization		4,778	4,419
Total intangible assets, Net		$ 3,583	1,742
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Weighted Average Amortization Period (Years)		4 years 6 months
Total intangible assets, Gross Carrying Amount		$ 272	272
Total intangible assets, Accumulated Amortization		227	211
Total intangible assets, Net		$ 45	61
Customer backlog
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Weighted Average Amortization Period (Years)		1 year 6 months
Total intangible assets, Gross Carrying Amount		$ 93	93
Total intangible assets, Accumulated Amortization		$ 93	93
Core technologies
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Weighted Average Amortization Period (Years)		5 years 1 month 6 days
Total intangible assets, Gross Carrying Amount		$ 5,796	5,796
Total intangible assets, Accumulated Amortization		4,325	4,115
Total intangible assets, Net		$ 1,471	$ 1,681
NB-IoT technologies
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Weighted Average Amortization Period (Years)	[1]	7 years
Total intangible assets, Gross Carrying Amount	[1]	$ 2,200
Total intangible assets, Accumulated Amortization	[1]	133
Total intangible assets, Net	[1]	$ 2,067

[1] During the first quarter of 2018, the Company entered into an agreement to acquire certain NB-IoT technologies to be used in the Company's research and development activities in the amount of $2,800, of which $600 has not been received. Of the $2,200, $1,350 has not resulted in cash outflows as of March 31, 2018.