Boca Oncology Partners (Details)	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011 USD ($)	Sep. 30, 2022 USD ($) ft²	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) ft²	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Boca Oncology Partners [Abstract]
Recorded investments			$ 152,000		$ 152,000		$ 141,000
Condensed Income Statement Information [Abstract]
Net income			(378,000)	$ (352,000)	(2,167,000)	$ (677,000)
USNC's equity in earnings (loss)			(156,000)	(77,000)	(1,287,000)	(351,000)
Condensed Balance Sheet Information [Abstract]
Current assets			703,000		703,000		2,243,000
TOTAL ASSETS			1,209,000		1,209,000		3,688,000
Current liabilities			336,000		336,000		626,000
Equity			862,000		862,000		3,028,000
TOTAL LIABILITIES AND EQUITY			1,209,000		1,209,000		3,688,000
Boca Oncology Partners RE, LLC ("BOPRE") [Member]
Condensed Income Statement Information [Abstract]
Rental income			0	0	0	0
Net income			16,000	19,000	52,000	75,000
Condensed Balance Sheet Information [Abstract]
Current assets			110,000		110,000		112,000
Noncurrent assets			757,000		757,000		757,000
TOTAL ASSETS			867,000		867,000		869,000
Current liabilities			0		0		0
Noncurrent liabilities			0		0		0
Equity			867,000		867,000		869,000
TOTAL LIABILITIES AND EQUITY			$ 867,000		$ 867,000		$ 869,000
Boca Oncology Partners, LLC [Member]
Boca Oncology Partners [Abstract]
Area of real estate property (in square foot) | ft²			6,000		6,000
Boca Oncology Partners RE, LLC ("BOPRE") [Member]
Boca Oncology Partners [Abstract]
Ownership percentage			24.36%		24.36%		24.36%
Recorded investments			$ 152,000		$ 152,000		$ 151,000
Condensed Income Statement Information [Abstract]
USNC's equity in earnings (loss)			$ 2,000	$ 4,000	$ 8,000	$ 16,000
Boca Oncology Partners RE, LLC ("BOPRE") [Member] | Boca West IMP [Member]
Boca Oncology Partners [Abstract]
Percentage of interest in medical office building		20.00%
Ownership percentage	23.75%
Additional investor purchased ownership percentage	3.75%
BOP and BOPRE [Member]
Boca Oncology Partners [Abstract]
Area of real estate property (in square foot) | ft²			32,000		32,000
Investments in unconsolidated entities		$ 225,000
Ownership percentage		22.50%