CB Oncology Partners (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Sep. 02, 2017
Condensed Income Statement Information [Abstract]
Patient revenue		$ 1,061,000	$ 747,000
USNC's equity in income (loss)		(139,000)	(146,000)
Condensed Balance Sheet Information [Abstract]
Current assets		3,451,000		$ 3,007,000
TOTAL ASSETS		4,614,000		4,173,000
Current liabilities		322,000		410,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY		4,614,000		4,173,000
CB Oncology Partners LLC [Member]
CB Oncology Partners [Abstract]
Ownership percentage	28.58%					24.00%
Capital called from members	$ 500,000
Advances converted into equity	121,000
Contribution in cash	$ 212,000
Outstanding amount		2,155,000		2,154,000
Outstanding amount, less allowances		1,251,000		1,251,000
Due from related parties		$ 904,000			$ 903,000
Note bearing interest		6.00%
Interest earned from the amounts owed by entity		$ 31,000	31,000
Accrued interest		304,000		273,000
CB Oncology Partners LLC [Member] | Investment in Unconsolidated Entity [Member]
Condensed Income Statement Information [Abstract]
Patient revenue		471,000	467,000
Net income (loss)		62,000	(216,000)
USNC's equity in income (loss)		18,000	$ (52,000)
Condensed Balance Sheet Information [Abstract]
Current assets		446,000		385,000
Noncurrent assets		4,121,000		4,271,000
TOTAL ASSETS		4,567,000		4,656,000
Current liabilities		3,154,000		3,181,000
Noncurrent liabilities		3,547,000		3,684,000
Deficit		(2,134,000)		(2,209,000)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY		$ 4,567,000		$ 4,656,000