Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 27, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jun. 30, 2015	May. 05, 2015
Business Acquisition [Line Items]
Business acquisition, acquired entity name				Nexgen Wireless, Inc.
Business acquisition, effective date				Feb. 27, 2015
Asset purchase, date of agreement				Feb. 27, 2015
Goodwill		$ 3,493		$ 3,493		$ 161
Decrease in goodwill		600
Increase (decrease) in cost of intangible assets				9,800
Revenue		26,526	$ 27,932	80,477	$ 77,769
Amortization of intangible assets		1,125	465	2,963	1,503
Pro Forma [Member]
Business Acquisition [Line Items]
Amortization of intangible assets			$ 600	400	$ 2,000
Nexgen Wireless, Inc. [Member]
Business Acquisition [Line Items]
Provisional purchase consideration	$ 21,400
Cash paid	18,250
Contingent consideration related to claims escrow	2,250	91		$ 91
Potential earn-out at fair value	100
Business acquisition estimated excess working capital paid	$ 800
Weighted average amortization period of intangible assets	5 years
Percentage of revenue				78.00%
Goodwill		3,332		$ 3,332
Assembled workforce, goodwill earned		1,500		1,500
Decrease in goodwill		600
Revenue						$ 23,800
Amortization of intangible assets				3,000
Nexgen APA Amendment [Member]
Business Acquisition [Line Items]
Contingent consideration related to claims escrow		5,000		5,000				$ 1,000
Portion of accounts receivable transferred								800
Escrowed funds payable								2,250
Adjustment to contingent consideration				900
Nexgen APA Amendment [Member] | Estimated Fair Value [Member]
Business Acquisition [Line Items]
Contingent consideration related to claims escrow		500		$ 500			$ 1,000	$ 2,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Increase (decrease) in cost of intangible assets		600
Customer Relationships [Member] | Nexgen Wireless, Inc. [Member]
Business Acquisition [Line Items]
Increase (decrease) in cost of intangible assets		$ 600