CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 30,308	$ 24,228
Short-term investments	0	14,932
Restricted cash	62	62
Contract and other receivables	4	0
Prepaid materials, net	3,010	3,010
Prepaid expenses and other current assets	1,178	1,847
Total current assets	34,562	44,079
Property and equipment, net	493	536
Intangibles, net	58	62
Right of use asset	1,902	2,039
Total assets	37,015	46,716
Current liabilities:
Accounts payable	581	175
Accrued liabilities	671	961
Accrued research and development expenses	538	1,252
Accrued compensation	1,022	2,205
Current portion of term loan, less debt issuance costs	3,716	4,511
Other current liabilities	2,294	2,553
Total current liabilities	8,822	11,657
Lease liability, less current portion	1,598	1,768
Total liabilities	10,420	13,425
Commitments and Contingencies
Stockholders’ equity:
Common stock, $0.001 par value; 300,000,000 shares authorized at March 31, 2023 and December 31, 2022; 16,859,733 and 16,840,261 shares issued and outstanding at March 31, 2023 (unaudited) and December 31, 2022, respectively	17	17
Additional paid-in capital	516,888	516,457
Accumulated other comprehensive loss	0	(12)
Accumulated deficit	(490,315)	(483,176)
Total stockholders’ equity	26,595	33,291
Total liabilities and stockholders’ equity	37,015	46,716
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