The Southern California Regional Gamma Knife Center (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 29, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Apr. 02, 2016	Dec. 31, 2015	Nov. 01, 2014
Schedule of Cost-method Investments [Line Items]
Renovation installation and operation agreement period				14 years
First payment due								$ 12,000
Repayment of amounts advanced to unconsolidated entities				$ 20,000	$ 0
Neuro Partners, LLC and CGK Condensed Income Statement Information [Abstract]
Patient revenue		$ 775,000	$ 672,000	1,607,000	1,481,000
USNC's equity in earnings (loss) of Neuro Partners, LLC and CGK		$ 183,000	25,000	$ 338,000	(11,000)
CGK [Member]
Schedule of Cost-method Investments [Line Items]
Ownership percentage		39.00%		39.00%
Neuro Partners LLC [Member]
Schedule of Cost-method Investments [Line Items]
Ownership percentage		20.00%		20.00%
Share of guarantee in lease obligations	20.00%			20.00%
Lease term	5 years			7 years
Operating lease payable	$ 1,663,000
Prior year lease obligations	$ 668,000
Debt maturity period	60 months
First payment due						$ 31,000
Neuro Partners LLC and CGK [Member]
Schedule of Cost-method Investments [Line Items]
Repayment of amounts advanced to unconsolidated entities		$ 20,000
Remaining amount of advances to unconsolidated entities				$ 116,000
Neuro Partners, LLC and CGK Condensed Income Statement Information [Abstract]
Patient revenue		211,000	295,000	516,000	498,000
Net income (loss)		50,000	1,000	176,000	(69,000)
USNC's equity in earnings (loss) of Neuro Partners, LLC and CGK		(9,000)	$ (5,000)	9,000	$ (38,000)
Neuro Partners, LLC and CGK Condensed Balance Sheet Information [Abstract]
Current assets		143,000		143,000			$ 66,000
Noncurrent assets		980,000		980,000			394,000
Total assets		1,123,000		1,123,000			460,000
Current liabilities		567,000		567,000			1,359,000
Noncurrent liabilities		1,281,000		1,281,000			0
Deficit		(725,000)		(725,000)			(899,000)
Total liabilities and equity		$ 1,123,000		$ 1,123,000			$ 460,000