Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Support contract timing			12 months
Customer deposits	$ 1,700	$ 1,500	$ 1,700	$ 1,500
Performance obligations	18,091	12,027	18,091	12,027	$ 11,082	$ 12,486
Recognition of revenue			11,437	7,727
Revenue	68,950	45,691	123,417	100,423
Service
Disaggregation of Revenue [Line Items]
Revenue	27,185	15,300	45,213	34,075
Restaurant/Retail
Disaggregation of Revenue [Line Items]
Recognition of revenue	8,800	3,600	11,400	7,700
Revenue	51,124	27,633	87,708	65,042
Restaurant/Retail | Hardware, Software And Service
Disaggregation of Revenue [Line Items]
Revenue		27,600		65,000
Government
Disaggregation of Revenue [Line Items]
Performance obligations	141,207		141,207		150,500
Funded performance obligations	32,100		32,100		$ 27,800
Revenue	$ 17,826	18,058	$ 35,709	35,381
Government | ISR solutions And Product
Disaggregation of Revenue [Line Items]
Revenue		$ 9,900		$ 18,800
Minimum
Disaggregation of Revenue [Line Items]
Payment period			30 days
Maximum
Disaggregation of Revenue [Line Items]
Payment period			90 days