Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Current assets:
Cash and cash equivalents	$ 1,940	$ 2,392
Accounts receivable, net	1,758	2,044
Inventory	641	645
Prepaid expenses and other current assets	407	426
Total current assets	4,746	5,507
Property and equipment, net	1,814	1,735
Right of use asset, net	951	1,001
Restricted cash	182	181
Inventory, non-current	204	137
Other assets, net	128	138
Total assets	8,025	8,699
Current liabilities:
Accounts payable and accrued expenses	758	654
Lease liability	241	236
Accrued protocol expense	91	35
Accrued radioactive waste disposal	100	94
Accrued payroll and related taxes	110	352
Accrued vacation	222	204
Total current liabilities	1,522	1,575
Non-current liabilities:
Lease liability, non-current	715	769
Accrued payroll and related taxes, non-current	108	55
Asset retirement obligation	585	577
Total liabilities	2,930	2,976
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $.001 par value; 7,000,000 shares authorized: Series B: 5,000,000 shares allocated; 59,065 shares issued and outstanding
Common stock, $.001 par value; 200,000,000 shares authorized; 68,897,779 and 68,897,779 shares issued and outstanding	69	69
Additional paid-in capital	93,677	93,592
Accumulated deficit	(88,651)	(87,938)
Total stockholders' equity	5,095	5,723
Series B Preferred Stock [Member]
Stockholders' equity:
Total liabilities and stockholders' equity	$ 8,025	$ 8,699