BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 60,011	$ 76,054
Receivables	0	1,111
Prepaid expenses and other current assets	1,350	1,666
Total current assets	61,361	78,831
Property and equipment, net	9,671	10,941
Right of use asset	2,357	4,420
Deposits	42	42
Other non-current assets	500	631
Total assets	73,931	94,865
Current liabilities:
Accounts payable	474	1,368
Current portion of long-term debt	20,051	7,868
Accrued expenses	5,725	6,076
Lease liability - current	525	729
Total current liabilities	26,775	16,041
Long-term debt	4,472	16,250
Lease liability - non-current	2,476	4,518
Other non-current liabilities	28	0
Total liabilities	33,751	36,809
Commitments and contingencies (Note 8)
Stockholders' equity:
Common stock $0.001 par value; 420,000,000 shares authorized, 216,174,542 shares issued and outstanding at June 30, 2022 and 350,000,000 shares authorized, 216,127,443 shares issued and outstanding at December 31, 2021	216	216
Additional paid-in capital	902,536	900,693
Accumulated deficit	(862,572)	(842,852)
Total stockholders' equity	40,180	58,057
Total liabilities and stockholders' equity	$ 73,931	$ 94,865