Note 9 - GKCE Acquisition - Assets Acquired and Liabilities Assumed (Details) - USD ($)		9 Months Ended
	Jun. 12, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Goodwill		$ 1,265,000		$ 1,265,000
First working capital payment		0	$ (43,000)
Estimated subsequent working capital payment		$ 0	$ (354,000)
Gamma Knife Center Ecuador S.A. (GKCE) [Member]
Cash and cash equivalents	$ 432,000
Accounts receivable	854,000
Prepaid expense and other	22,000
Purchased intangible assets	78,000
Goodwill	1,265,000
Total assets acquired	3,374,000
Accounts payable	(193,000)
Income taxes payable	(141,000)
Deferred income taxes	(66,000)
Employee compensation and benefits	(91,000)
Total liabilities assumed	(491,000)
Consideration allocated to assets acquired and liabilities assumed	2,883,000
First working capital payment	(515,000)
Estimated subsequent working capital payment	(368,000)
Base purchase consideration	2,000,000
Gamma Knife Center Ecuador S.A. (GKCE) [Member] | Building [Member]
Tangible assets	385,000
Gamma Knife Center Ecuador S.A. (GKCE) [Member] | Land [Member]
Tangible assets	19,000
Gamma Knife Center Ecuador S.A. (GKCE) [Member] | Medical Equipment [Member]
Tangible assets	$ 319,000