CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 17,799	$ 18,592
Prepaid expenses and other current assets	1,753	1,960
Total current assets	19,552	20,552
Other assets	673	733
Total assets	20,225	21,285
Current liabilities:
Accounts payable	2,553	3,890
Accrued expenses and other	8,980	9,058
Accrued dividends payable	0	64
Total current liabilities	11,533	13,012
Convertible notes payable and accrued interest, net of discounts - related party (Note 3)	30,200	29,964
Derivative liabilities (Note 4)	1,342	573
Borrowing and accrued interest under convertible line of credit, net of debt discount - related party (Note 9)	19,741	9,864
Other liabilities	55	66
Total liabilities	62,871	53,479
Commitments and contingencies (Note 10)
Series C super dividend redeemable convertible preferred stock; 1,000 shares authorized, 176 shares issued and outstanding at March 31, 2023 and December 31, 2022, redemption value: $8,256,000, liquidation value: $1,760,000 at March 31, 2023	1,723	1,723
Stockholders' equity (deficit):
Undesignated stock, $0.01 par value; 20,000,000 shares authorized, 20,000,000 designated at March 31, 2023 and December 31, 2022, respectively	0	0
Series A 12% convertible preferred stock; 1,742,500 shares authorized, 1,260,000 issued and outstanding at March 31, 2023 and December 31, 2022, liquidation value $1,260,500 at March 31, 2023	510	510
Common stock, $0.001 par value; 150,000,000 shares authorized at March 31, 2023 and December 31, 2022, 59,582,253 and 59,426,005 issued and outstanding at March 31, 2023 and December 31, 2022, respectively	59	59
Additional paid-in capital	276,156	275,081
Retained deficit	(321,094)	(309,567)
Total stockholders' equity (deficit)	(44,369)	(33,917)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 20,225	$ 21,285