Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Dec. 31, 2022	Jun. 30, 2022	[1]
Current assets
Cash and cash equivalents	$ 15,889	$ 26,453
Short-term investments	30,953	26,173
Accounts receivable	112	56
Cost and estimated revenue in excess of billings	4	2
Inventory, net:
Raw materials	1,012	864
Work-in-process	167	136
Finished goods	318	518
Prepaid expenses and other current assets	979	748
Total current assets	49,434	54,950
Property and equipment, net	1,554	1,098
Operating leases, right-of-use assets, net	336	162
Other assets, net	11	11
Total assets	51,335	56,221
Current liabilities
Accounts payable	301	169
Payroll related accruals	711	816
Accrued expenses and other liabilities	965	961
Income tax payable	1	2
Term note payable - related party	0	500
Lease liabilities, current	291	234
Total current liabilities	2,269	2,682
Lease liabilities, net of current portion	356	303
Total liabilities	2,625	2,985
Commitments and contingencies (Note 13)
Stockholders’ equity
Convertible preferred stock, $0.001 par value, 2,500,000 shares authorized; 280,898 shares of Series D issued and outstanding at December 31, 2022 and June 30, 2022	0	0
Common stock, $0.001 par value, 250,000,000 shares authorized at December 31, 2022 and June 30, 2022; 1,690,450 and 1,685,595 shares issued and outstanding at December 31, 2022 and June 30, 2022, respectively	190,643	190,642
Additional paid-in capital	80,295	79,505
Accumulated deficit	(220,659)	(215,712)
Accumulated other comprehensive loss	(1,569)	(1,199)
Total stockholders’ equity	48,710	53,236
Total liabilities and stockholders’ equity	$ 51,335	$ 56,221

[1] The balance sheet at June 30, 2022, has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by the United States generally accepted accounting principles for complete financial statements.