Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 24,228	$ 60,383
Short-term investments	14,932	0
Restricted cash	62	62
Prepaid materials, net	3,010	3,010
Prepaid expenses and other current assets	1,847	1,780
Total current assets	44,079	65,235
Property and equipment, net	536	281
Intangibles, net	62	83
Right of use asset	2,039	2,564
Other assets	0	291
Total assets	46,716	68,454
Current liabilities:
Accounts payable	175	285
Accrued liabilities	961	821
Accrued research and development expenses	1,252	810
Accrued compensation	2,205	2,016
Current portion of term loan, less debt issuance costs	4,511	0
Other current liabilities	2,553	1,295
Total current liabilities	11,657	5,227
Operating lease liability, less current portion	1,768	2,417
Term loan, less current portion and debt issuance costs	0	4,673
Other long-term liabilities	0	1,179
Total liabilities	13,425	13,496
Commitments and Contingencies
Stockholders’ equity (deficit):
Common stock, $0.001 par value; 300,000,000 and 400,000,000 shares authorized at December 31, 2022 and 2021, respectively; 16,840,261 and 14,597,118 shares issued and outstanding at December 31, 2022 and 2021, respectively	17	15
Additional paid-in capital	516,457	509,791
Accumulated other comprehensive loss	(12)	0
Accumulated deficit	(483,176)	(454,853)
Total stockholders’ equity	33,291	54,958
Total liabilities and stockholders’ equity	46,716	68,454
Class A-1 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	0	0
Class A-2 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	1	1
Class A-3 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	0	0
Class A-4 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	$ 4	$ 4