Revenue Recognition - Schedule of Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 54,847	$ 45,380	$ 155,270	$ 134,309
Mission Systems | Revision of Prior Period, Reclassification, Adjustment
Disaggregation of Revenue [Line Items]
Revenue		100
ISR Solutions | Revision of Prior Period, Reclassification, Adjustment
Disaggregation of Revenue [Line Items]
Revenue				900
Product
Disaggregation of Revenue [Line Items]
Revenue	20,470	15,904	51,437	46,149
Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	37,347	29,841	102,389	87,663
Government
Disaggregation of Revenue [Line Items]
Revenue	17,500	15,539	52,881	46,646
Point in Time | Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	29,739	23,934	77,373	66,916
Point in Time | Restaurant/Retail | Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	29,739	23,599	77,373	65,849
Point in Time | Restaurant/Retail | Grocery
Disaggregation of Revenue [Line Items]
Revenue		335		1,067
Point in Time | Restaurant/Retail | Mission Systems
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Point in Time | Restaurant/Retail | ISR Solutions
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Point in Time | Restaurant/Retail | Product
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Over Time | Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	7,608	5,907	25,016	20,747
Over Time | Restaurant/Retail | Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	7,608	5,508	25,016	18,718
Over Time | Restaurant/Retail | Grocery
Disaggregation of Revenue [Line Items]
Revenue		399		2,029
Over Time | Restaurant/Retail | Mission Systems
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Over Time | Restaurant/Retail | ISR Solutions
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Over Time | Restaurant/Retail | Product
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Over Time | Government
Disaggregation of Revenue [Line Items]
Revenue	17,500	15,539	52,881	46,646
Over Time | Government | Restaurant/Retail
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	0
Over Time | Government | Grocery
Disaggregation of Revenue [Line Items]
Revenue		0		0
Over Time | Government | Mission Systems
Disaggregation of Revenue [Line Items]
Revenue	8,084	8,444	24,620	25,177
Over Time | Government | ISR Solutions
Disaggregation of Revenue [Line Items]
Revenue	8,943	7,057	27,457	20,603
Over Time | Government | Product
Disaggregation of Revenue [Line Items]
Revenue	$ 473	$ 38	$ 804	$ 866