CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 17,966	$ 18,592
Prepaid expenses and other current assets	1,502	1,960
Total current assets	19,468	20,552
Other assets	613	733
Total assets	20,081	21,285
Current liabilities:
Accounts payable	1,976	3,890
Accrued expenses and other	7,913	9,058
Accrued dividends payable	64	64
Total current liabilities	9,953	13,012
Convertible notes payable and accrued interest, net of discounts - related party (Note 3)	30,433	29,964
Derivative liabilities (Note 4)	852	573
Borrowing and accrued interest under convertible line of credit, net of debt discount - related party (Note 9)	29,926	9,864
Other liabilities	44	66
Total liabilities	71,208	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 June 30, 2023 and December 31, 2022, redemption value: $8,282,000, liquidation value: $1,760,000 at June 30, 2023	1,723	1,723
Stockholders' equity (deficit):
Undesignated stock, $0.01 par value; 20,000,000 shares authorized, 20,000,000 designated at June 30, 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 June 30, 2023 and December 31, 2022, liquidation value $1,260,000 at June 30, 2023	510	510
Common stock, $0.001 par value; 150,000,000 shares authorized at June 30, 2023 and December 31, 2022, 59,582,253 and 59,426,005 issued and outstanding at June 30, 2023 and December 31, 2022, respectively	59	59
Additional paid-in capital	276,852	275,081
Accumulated deficit	(330,271)	(309,567)
Total stockholders' equity (deficit)	(52,850)	(33,917)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 20,081	$ 21,285