Property and Equipment (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment, Gross	$ 98,458,000	$ 100,157,000
Accumulated depreciation	(52,337,000)	(51,666,000)
Net property and equipment	46,121,000	48,491,000
Medical equipment and facilities [Member]
Property, Plant and Equipment, Gross	93,966,000	95,923,000
Office equipment [Member]
Property, Plant and Equipment, Gross	585,000	576,000
Deposits and construction in progress [Member]
Property, Plant and Equipment, Gross	1,907,000	1,658,000
Deposits towards purchase of proton beam systems [Member]
Property, Plant and Equipment, Gross	$ 2,000,000	$ 2,000,000

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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