Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment, Net [Abstract]
Gamma knife	$ 0	$ 5,337,000
Leasehold improvements	0	2,138,000
Less: Depreciation and amortization	0	(3,748,000)
Total property and equipment	0	3,727,000
Depreciation expense	754,000	830,000
Amortization expense	$ 229,000	$ 305,000