Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 39,769	$ 46,156
Restricted cash	1,501	1,501
Accounts receivable, interest and other receivables	207	205
Prepaid expenses and other current assets	1,943	1,269
Total current assets	43,420	49,131
Property and equipment, net	14	12
Total assets	43,434	49,143
Current liabilities:
Accounts payable	212	90
Accrued expenses and other current liabilities	3,347	3,849
Warrant derivative liability	4,410	2,773
Total liabilities	7,969	6,712
Commitments and contingencies
Redeemable preferred stock: $0.01 par value; 10,000,000 shares authorized Series 1 redeemable convertible preferred stock, $0.01 par value, 1,517,500 shares authorized at March 31, 2022 and December 31, 2021, 452,000 shares issued and outstanding at March 31, 2022 and December 31, 2021	18,036	18,036
Stockholders’ equity:
Common stock, $0.01 par value; 80,000,000 shares authorized at March 31, 2022 and December 31, 2021, 8,676,903 shares issued and 8,609,157 shares outstanding at March 31, 2022; 8,497,025 shares issued and 8,429,279 shares outstanding at December 31, 2021	87	85
Treasury stock: 67,746 shares held at March 31, 2022 and December 31, 2021	(5,056)	(5,056)
Additional paid-in capital	580,753	580,156
Accumulated other comprehensive loss	(341)	(338)
Accumulated deficit	(558,014)	(550,452)
Total stockholders’ equity	17,429	24,395
Total liabilities, redeemable preferred stock and stockholders' equity	$ 43,434	$ 49,143