Purchased Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 16,704	$ 16,354
Accumulated amortization	9,252	8,030
Net carrying amount	7,452	8,324
Developed Technology Rights [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	4,282	4,282
Accumulated amortization	2,249	1,820
Net carrying amount	2,033	2,462
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	9,011	9,011
Accumulated amortization	3,942	3,191
Net carrying amount	5,069	5,820
Order or Production Backlog [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	2,779	2,779
Accumulated amortization	2,779	2,779
Noncompete Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	282	282
Accumulated amortization	282	240
Net carrying amount		$ 42
Licensing Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	350
Net carrying amount	$ 350