Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 26,238	$ 144,514
Marketable securities	105,780	0
Prepaid expenses and other current assets	2,527	2,591
Total current assets	134,545	147,105
Property and equipment, net	1,850	2,243
Operating lease, right-of-use ("ROU") asset	3,541	4,089
Other assets	320	320
Total assets	140,256	153,757
Current liabilities:
Accounts payable	6,532	867
Accrued expenses	3,301	8,775
Operating lease obligations, current portion	1,051	989
Total current liabilities	10,884	10,631
Operating lease obligations, long-term portion	2,444	3,048
Total liabilities	13,328	13,679
Stockholders' equity:
Common stock, $0.0001 par value: 300,000 shares authorized; 101,284 and 101,303 shares issued at June 30, 2022 and December 31, 2021, respectively; 100,968 and 100,832 shares outstanding at June 30, 2022 and December 31, 2021, respectively	10	10
Additional paid-in-capital	376,675	373,657
Accumulated other comprehensive loss	(512)	0
Accumulated deficit	(249,245)	(233,589)
Total stockholders' equity	126,928	140,078
Total liabilities and stockholders' equity	$ 140,256	$ 153,757

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).