Property and Equipment (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 40,301	$ 41,480
Outside of the United States
Property, Plant and Equipment [Line Items]
Property and equipment, net	3,455
Gamma Knife
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 943
Medical Equipment and Facilities | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Medical Equipment and Facilities | Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
PBRT Equipment
Property, Plant and Equipment [Line Items]
Useful life	20 years