Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Dec. 31, 2019	Jun. 30, 2019
Current assets:
Cash and cash equivalents	$ 3,180	$ 5,326
Accounts receivable, net	1,409	1,154
Inventory	545	530
Prepaid expenses and other current assets	497	305
Total current assets	5,631	7,315
Property and equipment, net	1,736	1,609
Right of use asset, net (Note 9)	1,116
Restricted cash	181	181
Inventory, non-current	127	155
Other assets, net of accumulated amortization	142	162
Total assets	8,933	9,422
Current liabilities:
Accounts payable and accrued expenses	632	683
Lease liability (Note 9)	229
Accrued protocol expense	24	133
Accrued radioactive waste disposal	89	74
Accrued payroll and related taxes	203	89
Accrued vacation	163	142
Total current liabilities	1,340	1,121
Long-term liabilities:
Non-current Lease Liability	889
Asset retirement obligation	563	621
Total liabilities	2,792	1,742
Commitments and contingencies (Note 7)
Shareholders' equity:
Common stock, $.001 par value; 200,000,000 shares authorized; 67,388,047 shares issued and outstanding	67	67
Additional paid-in capital	92,279	92,105
Accumulated deficit	(86,205)	(84,492)
Total shareholders' equity	6,141	7,680
Total liabilities and shareholders' equity	8,933	9,422
Series B Preferred Stock [Member]
Shareholders' equity:
Preferred stock