CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 1,068	$ 2,356
Short-term investments	0	1,991
Unbilled receivables	0	30
Prepaid expenses and other current assets	332	641
Total current assets	1,400	5,018
Restricted cash	264	264
Property and equipment, net	548	775
Right-of-use assets	1,653	1,961
Other assets	42	67
Total assets	3,907	8,085
Current Liabilities:
Accounts payable	1,202	109
Accrued expenses	2,010	926
Lease liabilities	669	575
Convertible note payable, net of issuance costs (Note12)	984	0
Total current liabilities	4,865	1,610
Lease liabilities, net of current portion	1,525	2,075
Total liabilities	6,390	3,685
Commitments and contingencies (Note 7)
Stockholders' Equity (Deficit):
Preferred stock ($0.01 par value per share); 5,000,000 shares authorized; no shares issued or outstanding	0	0
Common stock ($0.01 par value per share); 60,000,000 shares authorized at December 31, 2023 and 2022, and 12,032,425 and 4,944,202 shares issued and outstanding at December 31, 2023 and 2022, respectively	120	49
Additional paid-in capital	411,814	404,277
Accumulated other comprehensive loss	(265)	(229)
Accumulated deficit	(414,152)	(399,697)
Total stockholders' equity (deficit)	(2,483)	4,400
Total liabilities and stockholders' equity (deficit)	$ 3,907	$ 8,085