Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20,608,000	$ 17,935,000
Less: accumulated depreciation and amortization	(10,741,000)	(9,928,000)
Property and equipment, net	9,867,000	8,007,000
Depreciation expense	926,000	821,000
Land and land improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,538,000	1,335,000
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	5,394,000	5,265,000
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,913,000	9,363,000
Rental equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,763,000	$ 1,972,000