Note 2 - Property and Equipment - Summary of Property and Equipment (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Property and equipment, gross		$ 74,237,000
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization, Total	$ 79,620,000
Accumulated depreciation	(54,442,000)	(50,770,000)
Net property and equipment	25,178,000	23,467,000
Property and equipment, net	25,178,000	23,467,000
Non-US [Member]
Net property and equipment	4,038,000	2,201,000
Property and equipment, net	4,038,000	2,201,000
Medical Equipment and Facilities [Member]
Property and equipment, gross	73,884,000	73,709,000
Office Equipment [Member]
Property and equipment, gross	300,000	422,000
Construction in Progress [Member]
Property and equipment, gross	$ 5,436,000	$ 106,000