Goodwill and Intangible Assets, Net - Components of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets, Net [Abstract]
Gross	$ 61,648	$ 61,766
Accumulated Amortization	(33,872)	(32,725)
Net	27,776	29,041
Gross value of fully amortized intangible assets	6,500	6,000
Distribution rights
Finite-Lived Intangible Assets, Net [Abstract]
Gross	353	344
Accumulated Amortization	(177)	(165)
Net	176	179
Patents
Finite-Lived Intangible Assets, Net [Abstract]
Gross	13,258	13,250
Accumulated Amortization	(5,088)	(5,310)
Net	8,170	7,940
Trademarks and trade names
Finite-Lived Intangible Assets, Net [Abstract]
Gross	2,776	2,786
Accumulated Amortization	(1,663)	(1,594)
Net	1,113	1,192
Developed and core technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross	12,544	12,560
Accumulated Amortization	(6,565)	(6,071)
Net	5,979	6,489
Capitalized software development costs
Finite-Lived Intangible Assets, Net [Abstract]
Gross	142	142
Accumulated Amortization	(95)	(77)
Net	47	65
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross	32,425	32,534
Accumulated Amortization	(20,134)	(19,395)
Net	12,291	13,139
Order backlog
Finite-Lived Intangible Assets, Net [Abstract]
Gross	150	150
Accumulated Amortization	(150)	(113)
Net	$ 0	$ 37