Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Jun. 30, 2016
Current assets:
Cash and cash equivalents	$ 6,668	$ 10,139
Certificates of deposit (Note 3)	5,279	2,247
Accounts receivable, net of allowance for doubtful accounts of $30 and $30, respectively	627	605
Inventory	381	334
Prepaid expenses and other current assets	224	304
Total current assets	13,179	13,629
Property and equipment, net	779	577
Certificates of deposit, non-current (Note 3)	0	2,973
Restricted cash	181	181
Inventory, non-current	568	591
Other assets, net of accumulated amortization	278	151
Total assets	14,985	18,102
Current liabilities:
Accounts payable and accrued expenses	312	612
Accrued protocol expense	156	122
Accrued radioactive waste disposal	195	177
Accrued payroll and related taxes	90	72
Accrued vacation	118	111
Total current liabilities	871	1,094
Long-term liabilities:
Warrant derivative liability	0	27
Asset retirement obligation	547	580
Total liabilities	1,418	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	82,901	82,788
Accumulated deficit	(69,389)	(66,442)
Total shareholders' equity	13,567	16,401
Total liabilities and shareholders' equity	14,985	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