CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 36,559	$ 33,406
Prepaid expenses and other current assets	4,383	2,063
Total current assets	40,942	35,469
Property and equipment, net	64	106
Right-of-use lease asset	30	1,227
Non-current deposits	1,551	0
Total assets	42,587	36,802
Current liabilities:
Accounts payable	2,117	514
Accrued and other current liabilities	3,177	1,972
Total current liabilities	5,294	2,486
Lease liability	30	1,057
Total liabilities	5,324	3,543
Stockholders' equity:
Preferred stock, value
Common stock, $0.001 par value; 100,000,000 shares authorized at December 31, 2020 and December 31, 2021; 6,246,896 and 9,993,135 shares issued and outstanding at December 31, 2020 and December 31, 2021.	10	6
Additional paid-in capital	422,960	400,071
Accumulated other comprehensive loss	(748)	(746)
Accumulated deficit	(384,959)	(366,072)
Total stockholders' equity	37,263	33,259
Total liabilities and stockholders' equity	42,587	36,802
6% convertible exchangeable preferred stock
Stockholders' equity:
Preferred stock, value	0	0
Series A convertible preferred stock
Stockholders' equity:
Preferred stock, value	0	0
Series B Convertible Preferred Stock
Stockholders' equity:
Preferred stock, value	$ 0	$ 0

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).