The Southern California Regional Gamma Knife Center (Details) (USD $)	9 Months Ended						3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 CGK [Member]	Sep. 30, 2012 CGK [Member] USNC [Member]	Mar. 31, 2012 CGK [Member] USNC [Member]	Dec. 31, 2011 CGK [Member] USNC [Member]	Sep. 30, 2012 Neuro Partners LLC [Member]	Sep. 30, 2011 Neuro Partners LLC [Member]	Sep. 30, 2012 Neuro Partners LLC [Member]	Sep. 30, 2011 Neuro Partners LLC [Member]	Dec. 31, 2011 Neuro Partners LLC [Member]	Sep. 30, 2012 Neuro Partners LLC [Member] USNC [Member]
Schedule of Equity Method Investments [Line Items]
Renovation installation and operation agreement period			14 years
Ownership percentage (in hundredths)					39.00%	44.00%						20.00%
Initial ownership percentage (in hundredths)				27.00%
Neuro Partners LLC Condensed Income Statement Information [Abstract]
Net sales							$ 222,000	$ 222,000	$ 666,000	$ 666,000
Net income (loss)							(11,000)	95,000	(22,000)	76,000
USNC's equity in loss of Neuro Partners LLC	24,000	0					(2,000)	19,000	(4,000)	15,000
Neuro Partners LLC Condensed Balance Sheet Information [Abstract]
Current assets							432,000		432,000		482,000
Noncurrent assets							2,420,000		2,420,000		2,603,000
Total assets							2,852,000		2,852,000		3,085,000
Current liabilities							580,000		580,000		22,000
Noncurrent liabilities							2,449,000		2,449,000		3,144,000
Equity							(177,000)		(177,000)		(81,000)
Total liabilities and equity							$ 2,852,000		$ 2,852,000		$ 3,085,000