Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 79,526	$ 88,460
Restricted cash	110	110
Prepaid materials	1,095	1,487
Prepaid expenses and other current assets	987	2,162
Total current assets	81,718	92,219
Investment in equity securities	1,710	1,710
Other assets	2,430	2,323
Total Assets	85,858	96,252
Current liabilities
Accounts payable	1,056	806
Accrued expenses	1,907	973
Payroll liabilities	939	1,654
Other current liabilities	1,794	1,803
Total current liabilities	5,696	5,236
Total Liabilities	5,696	5,236
Commitments and contingencies (Note 13)
Stockholders' equity
Convertible preferred stock - $0.001 par value; 10,000,000 shares authorized; 582 shares issued and outstanding as of June 30, 2024 and December 31, 2023	0	0
Common stock - $0.18 par value; 350,000,000 and 175,000,000 shares authorized as of June 30, 2024 and December 31, 2023, respectively; 125,757,416 and 125,304,064 shares issued and outstanding as of June 30, 2024 and December 31, 2023, respectively	22,874	22,792
Additional paid-in capital	256,978	255,987
Treasury stock, at cost; 1,320,046 shares of common stock at June 30, 2024 and December 31, 2023	(1,475)	(1,475)
Accumulated deficit	(198,215)	(186,288)
Total Stockholders' Equity	80,162	91,016
Total Liabilities and Stockholders' Equity	$ 85,858	$ 96,252