Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 86,508	$ 24,930
Short-term investments	39,000	20,000
Prepaid expenses and other current assets	1,567	1,395
Total current assets	127,075	46,325
Right-of-use asset	394	966
Other assets	45	165
Total assets	127,514	47,456
Current liabilities:
Accounts payable	1,557	1,544
Accrued expenses	3,281	4,197
Current portion of operating lease liabilities	365	649
Total current liabilities	5,203	6,390
Long-term portion of operating lease liabilities		397
Total liabilities	5,203	6,787
Commitments (Note 7)
Stockholders' equity:
Preferred Stock
Common stock, $0.001 par value per share, 150,000,000 shares authorized; 13,016,955 and 3,347,386 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively	13	4
Additional paid-in capital	481,709	301,562
Accumulated other comprehensive loss
Accumulated deficit	(455,809)	(260,897)
Total stockholders' equity	122,311	40,669
Total liabilities and stockholders' equity	127,514	$ 47,456
Series X redeemable convertible preferred stock
Stockholders' equity:
Preferred Stock	$ 96,398

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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- 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).