Note 10 - Related Party Transactions - Schedule of Related Party Transactions (Details) - US Subsidiary Of Elekta Member - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Equipment purchases and de-install costs	$ 231,000	$ 97,000	$ 1,594,000	$ 1,616,000
Costs incurred to maintain equipment	272,000	125,000	820,000	593,000
Total related party transactions	503,000	$ 222,000	2,414,000	$ 2,209,000
Commitments	10,551,000		10,551,000		$ 6,624,000
Accounts payable and other accrued liabilities	$ 748,000		$ 748,000		$ 1,992,000