Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 40,368	$ 88,539
Marketable securities	34,728	12,108
Accounts receivable, net	12,996	0
Other receivables	617	1,028
Inventories	9,230	0
Prepaid expenses and other current assets	3,072	2,277
Total current assets	101,011	103,952
Property and equipment, net	476	455
Facility and equipment under lease	1,694	2,505
Other assets	157	4,636
Total assets	103,338	111,548
Current liabilities:
Accounts payable and other accrued liabilities	38,105	41,258
Accrued payroll and benefits	4,580	11,971
Total current liabilities	42,685	53,229
Loan payable, long-term	28,666	0
Other long-term liabilities	4,099	10,766
Total liabilities	75,450	63,995
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value; 300,000,000 shares authorized; 202,827,831 and 164,502,013 issued and outstanding at December 31, 2022 and 2021, respectively	203	165
Additional paid-in capital	1,149,926	1,094,353
Accumulated other comprehensive loss	(2,917)	(3,042)
Accumulated deficit	(1,119,324)	(1,043,923)
Total stockholders’ equity	27,888	47,553
Total liabilities and stockholders’ equity	$ 103,338	$ 111,548