Interim Financial Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Contract retentions	$ 1,596		$ 1,596		$ 1,065
Allowance for doubtful accounts	$ 246		$ 246		$ 208
Licensing contract term			5 years
Minimum
Deferred Revenue Arrangement [Line Items]
Royalty percent earned on licensing agreement	4.00%		4.00%
Maximum
Deferred Revenue Arrangement [Line Items]
Royalty percent earned on licensing agreement	6.00%		6.00%
Cost of Goods Sold
Deferred Revenue Arrangement [Line Items]
Prior period reclassification adjustment	$ 78	$ 60	$ 243	$ 86
General and Administrative Expense
Deferred Revenue Arrangement [Line Items]
Prior period reclassification adjustment	$ (78)	$ (60)	$ (243)	$ (86)