CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 8,902	$ 20,054
Prepaid expenses and other current assets	4,187	5,741
Total current assets	13,089	25,795
Other assets	21	21
Total assets	13,110	25,816
Current liabilities:
Accounts payable	3,631	2,076
Accrued and other current liabilities	4,728	4,855
Accrued clinical site costs	575	914
Convertible note payable and accrued interest - short term	10,069	7,703
D&O insurance payable	314
Warrant liabilities	10	37
Total current liabilities	19,327	15,585
Convertible note payable and accrued interest - long term		2,822
Total liabilities	19,327	18,407
Common stock, $0.001 par value, 500,000,000 shares authorized; 83,919,554 and 66,442,989 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	84	67
Additional paid-in capital	242,533	230,339
Accumulated other comprehensive loss	(22)
Accumulated deficit	(248,815)	(222,997)
Total stockholders' (deficit) equity	(6,217)	7,409
Total liabilities and stockholders' (deficit) equity	13,110	25,816
Series A Convertible Preferred Stock
Current liabilities:
Preferred stock, $0.001 par value, 50,000,000 shares authorized; Series A convertible preferred stock, $0.001 par value, 12,000,000 shares authorized; 3,000,000 and 0 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	$ 3