Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 11,382	$ 17,578
Short-term investments	11,872	12,136
Accounts receivable, less current expected credit loss of $111 and $111, respectively	7,104	6,729
Inventories, net	537	439
Prepaid expenses and other current assets	1,295	1,439
Total current assets	32,190	38,321
Property and equipment, net of accumulated depreciation of $18,763 and $18,703, respectively	4,572	4,539
Goodwill	2,116	2,116
Other intangible assets, net of accumulated amortization of $483 and $468, respectively	343	358
Right-of-use operating lease assets, net	582	609
Long-term investments	8,879	3,664
Other assets	764	781
Total assets	49,446	50,388
Current liabilities:
Accounts payable	1,852	2,421
Accrued liabilities:
Operating lease liabilities - current	105	81
Employee compensation	1,289	1,252
Other accrued liabilities	1,284	1,934
Total current liabilities	4,530	5,688
Operating lease liabilities - non-current	512	533
Deferred income taxes, net	172	172
Other liabilities	276	281
Total liabilities	5,490	6,674
Stockholders’ equity:
Common stock, $.01 par value, 40,000,000 shares authorized, 31,361,303 and 31,361,303 shares issued, and 30,385,297 and 30,385,297 shares outstanding, respectively	313	313
Additional paid-in capital	164,957	164,853
Accumulated deficit	(117,248)	(117,529)
Accumulated other comprehensive loss	(1,891)	(1,748)
Nil coupon perpetual loan notes	76	76
Treasury stock, at cost	(2,251)	(2,251)
Total stockholders’ equity	43,956	43,714
Total liabilities and stockholders’ equity	$ 49,446	$ 50,388