Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 21,838	$ 28,699
Prepaid expenses and other current assets	650	309
Total current assets	22,488	29,008
Property and equipment, net	176	196
Long-term prepaid maintenance and supplies	91	91
Security deposit	14	14
Operating lease right-of-use asset	801	900
Financing lease right-of-use-asset	5,212	5,851
Total assets	28,782	36,060
Current liabilities:
Accounts payable	434	338
Accrued expenses	213	203
Accrued payroll related expenses	510	601
Current operating lease liability	243	216
Current financing lease liability	1,395	1,395
Total current liabilities	2,795	2,753
Long-term operating lease liability	658	768
Long-term financing lease liability	3,579	4,158
Total liabilities	7,032	7,679
Commitments and contingencies (see Note 10)
Stockholders’ equity:
Preferred stock $0.001 par value, authorized 2,500 shares; none issued and outstanding at June 30, 2022 and December 31, 2021	0	0
Common stock: $0.001 par value, authorized 47,500 shares; 23,457 and 23,207 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively;	23	23
Additional paid-in capital	196,148	194,212
Accumulated deficit	(174,421)	(165,854)
Total stockholders’ equity	21,750	28,381
Total liabilities and stockholders’ equity	$ 28,782	$ 36,060