Identifiable Intangible Assets and Goodwill - Narrative (Details)	1 Months Ended	3 Months Ended			9 Months Ended
	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Finite-Lived Intangible Assets [Line Items]
Research and development		$ 4,210,000		$ 3,448,000	$ 13,613,000	$ 9,233,000
Capitalized software development costs		2,400,000		700,000	6,700,000	2,300,000
Amortization of capitalized software development costs		1,700,000		500,000	4,900,000	1,500,000
Cost of sales		43,176,000		36,384,000	123,473,000	107,459,000
Amortization of identifiable intangible assets		257,000		0	$ 677,000	0
Number of operating segments | segment					2
Goodwill		41,214,000			$ 41,214,000		$ 41,386,000
Settlement of working capital for acquisitions	$ 200,000		$ 200,000		191,000	0
Goodwill impairment charge		0		0	0	0
Restaurant/Retail And Government Reporting Segments
Finite-Lived Intangible Assets [Line Items]
Goodwill		41,200,000			41,200,000		$ 41,400,000
Acquisitions
Finite-Lived Intangible Assets [Line Items]
Cost of sales		1,600,000		$ 700,000	4,700,000	2,400,000
Amortization of identifiable intangible assets		$ 300,000			$ 700,000
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life					3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life					5 years
Internally developed software costs not meeting general release threshold
Finite-Lived Intangible Assets [Line Items]
Research and development					$ 5,300,000	$ 2,500,000