Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Feb. 28, 2015	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Change in goodwill					$ 0
Amortization of intangible assets		$ 291,000	$ 291,000		872,000	$ 908,000
Increase (decrease) in cost of intangible assets					$ 900,000
Customer Contracts and Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets basis over estimated useful lives					5 years
RF Solutions [Member] | Customer Contracts and Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Impairment of intangible assets				$ 1,100,000		4,700,000	$ 5,800,000
Continuing Operations [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets		300,000	300,000		$ 900,000	900,000
Discontinued Operations [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets		0	100,000		0	1,000,000
Cost of Revenues [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets		$ 200,000	$ 200,000		$ 500,000	$ 500,000
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets basis over estimated useful lives					1 year
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets basis over estimated useful lives					6 years
Nexgen Wireless, Inc. [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill acquired	$ 3,300,000