Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 125,537	$ 136,377
Restricted cash	110	110
Prepaid expenses	5,304	2,488
Research and development rebate receivable	900	1,072
Other current assets	1,570	1,193
Total current assets	133,421	141,240
Other assets	627	22
Total Assets	134,048	141,262
Current liabilities
Accounts payable	2,052	1,717
Accrued expenses	834	204
Payroll liabilities	875	1,184
Other current liabilities	31	21
Total current liabilities	3,792	3,126
Total Liabilities	3,792	3,126
Commitments and contingencies (Note 13)
Stockholders' equity
Preferred stock - $0.001 par value; 10,000 shares authorized; 1 share issued and outstanding as of June 30, 2022 and December 31, 2021	0	0
Common stock - $0.18 par value; 175,000 shares authorized; 126,624 shares issued and outstanding as of June 30, 2022 and December 31, 2021	22,792	22,792
Additional paid-in capital - common stock	247,573	243,996
Accumulated deficit	(140,691)	(129,234)
Total Stockholders' Equity	130,256	138,136
Total Liabilities and Stockholders' Equity	134,048	141,262
Series B Preferred Stock [Member]
Stockholders' equity
Additional paid-in capital - Series B convertible preferred stock	$ 582	$ 582