CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 33,406	$ 11,885
Prepaid expenses and other current assets	2,063	2,132
Total current assets	35,469	14,017
Property and equipment, net	106	27
Right-of-use lease asset	1,227	1,264
Total assets	36,802	15,308
Current liabilities:
Accounts payable	514	890
Accrued and other current liabilities	1,972	1,530
Total current liabilities	2,486	2,420
Lease liability	1,057	1,191
Total liabilities	3,543	3,611
Stockholders' equity:
Preferred stock, value
Common stock, $0.001 par value; 100,000,000 shares authorized at December 31, 2019 and December 31, 2020; 859,998 and 6,246,896 shares issued and outstanding at December 31, 2019 and December 31, 2020.	6	1
Additional paid-in capital	400,071	370,142
Accumulated other comprehensive loss	(746)	(819)
Accumulated deficit	(366,072)	(357,627)
Total stockholders' equity	33,259	11,697
Total liabilities and stockholders' equity	36,802	15,308
6% Convertible Exchangeable Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value
Series A Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value
Series B Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value

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).