Identifiable Intangible Assets and Goodwill - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Finite-Lived Intangible Assets [Line Items]
Research and development	$ 4,538,000	$ 2,725,000	$ 9,403,000	$ 5,786,000
Capitalized software development costs	2,600,000	600,000	4,300,000	1,600,000
Amortization of capitalized software development costs	1,500,000	700,000	3,100,000	1,500,000
Cost of sales	36,612,000	35,916,000	80,297,000	71,074,000
Amortization of identifiable intangible assets	210,000	0	$ 420,000	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		172,000	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	800,000	$ 200,000	1,700,000	400,000
Amortization of identifiable intangible assets	$ 200,000		$ 400,000
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life			3 years
Minimum | Internal use software
Finite-Lived Intangible Assets [Line Items]
Useful life			3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life			5 years
Maximum | Internal use software
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			$ 3,500,000	$ 2,500,000