Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Jun. 30, 2016
Current assets:
Cash and cash equivalents	$ 5,100	$ 10,139
Certificates of deposit (Note 3)	5,307	2,247
Accounts receivable, net of allowance for doubtful accounts of $30 and $30, respectively	854	605
Inventory	314	334
Prepaid expenses and other current assets	348	304
Total current assets	11,923	13,629
Property and equipment, net	1,013	577
Certificates of deposit, non-current (Note 3)	0	2,973
Restricted cash	181	181
Inventory, non-current	557	591
Other assets, net of accumulated amortization	267	151
Total assets	13,941	18,102
Current liabilities:
Accounts payable and accrued expenses	706	612
Accrued protocol expense	84	122
Accrued radioactive waste disposal	203	177
Accrued payroll and related taxes	25	72
Accrued vacation	122	111
Total current liabilities	1,140	1,094
Long-term liabilities:
Warrant derivative liability	0	27
Asset retirement obligation	554	580
Total liabilities	1,694	1,701
Commitments and contingencies (Note 8)
Shareholders' equity:
Common stock, $.001 par value; 192,998,329 shares authorized; 55,017,419 and 55,010,619 shares issued and outstanding	55	55
Additional paid-in capital	82,941	82,788
Accumulated deficit	(70,749)	(66,442)
Total shareholders' equity	12,247	16,401
Total liabilities and shareholders' equity	13,941	18,102
Series A Preferred Stock [Member]
Shareholders' equity:
Preferred Stock, Value, Issued	0	0
Series B Preferred Stock [Member]
Shareholders' equity:
Preferred Stock, Value, Issued	0	0
Series C Preferred Stock [Member]
Shareholders' equity:
Preferred Stock, Value, Issued	0	0
Series D Preferred Stock [Member]
Shareholders' equity:
Preferred Stock, Value, Issued	$ 0	$ 0