Revenue - Disaggregated Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total Revenues	$ 16,070	$ 13,548	$ 40,708	$ 31,780
United States
Disaggregation of Revenue [Line Items]
Total Revenues	11,629	8,888	30,701	21,537
South America
Disaggregation of Revenue [Line Items]
Total Revenues	278	35	904	260
Europe
Disaggregation of Revenue [Line Items]
Total Revenues	1,907	2,532	4,935	4,513
Asia
Disaggregation of Revenue [Line Items]
Total Revenues	2,256	2,093	4,168	5,470
Total Foreign Revenues
Disaggregation of Revenue [Line Items]
Total Revenues	$ 4,441	$ 4,660	$ 10,007	$ 10,243