CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 53,902	$ 60,383
Restricted cash	62	62
Contract and other receivables	8	0
Prepaid materials, net	3,010	3,010
Prepaid expenses and other current assets	951	1,780
Total current assets	57,933	65,235
Property and equipment, net	394	281
Intangibles, net	74	83
Right of use asset	2,436	2,564
Other assets	148	291
Total assets	60,985	68,454
Current liabilities:
Accounts payable	625	285
Accrued liabilities	827	821
Accrued research and development expenses	608	810
Accrued compensation	858	2,016
Current portion of term loan, less debt issuance costs	826	0
Other current liabilities	957	1,295
Total current liabilities	4,701	5,227
Term loan, less debt issuance costs	3,588	4,673
Lease liability, less current portion	2,262	2,417
Other long-term liabilities	1,193	1,179
Total liabilities	11,744	13,496
Commitments and Contingencies	0	0
Stockholders’ equity:
Common stock, $0.001 par value; 400,000,000 shares authorized at March 31, 2022 and December 31, 2021; 145,981,180 and 145,971,184 shares issued and outstanding at March 31, 2022 (unaudited) and December 31, 2021, respectively	146	146
Additional paid-in capital	510,662	509,660
Accumulated deficit	(461,572)	(454,853)
Total stockholders’ equity	49,241	54,958
Total liabilities and stockholders’ equity	60,985	68,454
Class A-1 Convertible Preferred Stock
Stockholders’ equity:
Preferred stock	0	0
Class A-2 Convertible Preferred Stock
Stockholders’ equity:
Preferred stock	1	1
Class A-3 Convertible Preferred Stock
Stockholders’ equity:
Preferred stock	0	0
Class A-4 Convertible Preferred Stock
Stockholders’ equity:
Preferred stock	$ 4	$ 4