Intangibles - Amortization of Intangible Assets Acquired (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Capitalized patent costs	$ 7,136	$ 6,779
Intangible assets acquired:
Gross intangible assets	10,406	10,049
Accumulated amortization	(3,947)	(3,436)
Intangibles, net	6,459	6,613
Purchased Patents and Intellectual Property [Member]
Intangible assets acquired:
Intangible assets amount	250	250
Existing Technology [Member]
Intangible assets acquired:
Intangible assets amount	1,560	1,560
Customer Relationships [Member]
Intangible assets acquired:
Intangible assets amount	290	290
Backlog [Member]
Intangible assets acquired:
Intangible assets amount	760	760
Tradenames [Member]
Intangible assets acquired:
Intangible assets amount	290	290
Non-solicitation Agreements [Member]
Intangible assets acquired:
Intangible assets amount	$ 120	$ 120