Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Current assets:
Cash and cash equivalents	$ 63,828	$ 2,392
Accounts receivable, net	2,013	2,044
Inventory	980	645
Prepaid expenses and other current assets	481	426
Total current assets	67,302	5,507
Non-current assets:
Property and equipment, net	1,958	1,735
Right of use asset, net	768	1,001
Restricted cash	182	181
Inventory, non-current	76	137
Other assets, net	130	138
Total assets	70,416	8,699
Current liabilities:
Accounts payable and accrued expenses	730	654
Lease liability	252	236
Accrued protocol expense	98	35
Accrued radioactive waste disposal	100	94
Accrued payroll and related taxes	362	352
Accrued vacation	259	204
Total current liabilities	1,801	1,575
Non-current liabilities:
Lease liability, non-current	524	769
Accrued payroll and related taxes, non-current	77	55
Asset retirement obligation	608	577
Total liabilities	3,010	2,976
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $.001 par value; 7,000,000 shares authorized: Series B: 5,000,000 shares allocated; no and 59,065 shares issued and outstanding
Common stock, $.001 par value; 200,000,000 shares authorized; 141,915,266 and 68,897,779 shares issued and outstanding	142	69
Additional paid-in capital	158,589	93,592
Accumulated deficit	(91,325)	(87,938)
Total stockholders' equity	67,406	5,723
Series B Preferred Stock [Member]
Stockholders' equity:
Total liabilities and stockholders' equity	$ 70,416	$ 8,699