Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue from Contract with Customer [Abstract]
Percentage of total revenue accounted for percentage-of-completion revenue, less than	0.10%	0.10%	0.10%	0.10%
Product sales as a percentage of total revenue	95.00%	95.00%	95.00%	95.00%
Performance obligation, description of timing			Practical Expedients and Exemptions The Company has elected to apply several practical expedients as discussed below: Sales commissions are expensed when incurred because the amortization period would have been one year or less. These costs are recorded within segment selling and administrative expenses. The majority of the Company’s services are short-term in nature with a contract term of one year or less. For those contracts, the Company has utilized the practical expedient in ASC 606-10-50-14, exempting the Company from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. The Company’s payment terms are short-term in nature with settlements of one year or less. The Company has utilized the practical expedient in ASC 606-10-32-18, exempting the Company from adjusting the promised amount of consideration for the effects of a significant financing component given that the period between when the Company transfers a promised good or service to a customer and when the customer pays for that good or service will be one year or less. In most service contracts, the Company has the right to consideration from a customer in an amount that corresponds directly with the value to the customer of the Company’s performance completed to date. For these contracts, the Company has utilized the practical expedient in ASC 606-10-55-18, allowing the Company to recognize revenue in the amount to which it has a right to invoice. Accordingly, the Company does not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less and (ii) contracts for which the Company recognizes revenue at the amount to which it has the right to invoice for services performed.
Disaggregation of Revenue [Line Items]
Revenue	$ 70,989	$ 79,458	$ 190,591	$ 244,589
Cost of revenue (excluding depreciation and amortization)	54,083	57,191	146,522	167,389
Products
Disaggregation of Revenue [Line Items]
Revenue	69,671	77,956	186,552	240,306
Cost of revenue (excluding depreciation and amortization)	52,647	55,846	142,670	163,587
Services
Disaggregation of Revenue [Line Items]
Revenue	1,318	1,502	4,039	4,283
Cost of revenue (excluding depreciation and amortization)	$ 1,436	$ 1,345	$ 3,852	$ 3,802