Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 66,104	$ 70,903
Prepaid expenses and other current assets	1,156	1,594
Total current assets	67,260	72,497
Furniture and equipment, net	312	338
Intangible assets	11,148	11,148
Operating lease right-of-use asset	81	107
Total assets	78,801	84,090
Current liabilities:
Accounts payable	2,224	1,364
Accrued expenses and other current liabilities	2,610	2,258
Total current liabilities	4,834	3,622
Operating lease liability - long-term, net of current portion	50	63
Warrant liability - long-term	1,252	1,412
Total liabilities	6,136	5,097
Commitments and contingencies (Note 7)
Stockholders' equity
Preferred stock, $0.001 par value; 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock, $0.001 par value; 100,000,000 shares authorized; 28,578,338 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	29	29
Additional paid-in capital	152,260	151,733
Accumulated other comprehensive income	53	41
Accumulated deficit	(79,677)	(72,810)
Total stockholders’ equity	72,665	78,993
Total liabilities and stockholders’ equity	$ 78,801	$ 84,090