CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 70,023	$ 56,845
Restricted cash	1,115	364
Marketable securities	263,676	115,901
Interest and other receivables	1,655	3,144
Prepaid and other current assets	4,879	3,992
Total current assets	341,348	180,246
Noncurrent marketable securities	43,298
Property and equipment, net	1,177	793
Operating leases, right-of-use assets	3,556	4,147
Deposits and other assets	4,697	5,389
Total assets	394,076	190,575
Current liabilities:
Accounts payable	6,161	10,190
Accrued compensation and benefits	13,759	11,534
Operating lease liabilities	949	925
Debt	46,893	20,945
Accrued liabilities	40,308	33,100
Total current liabilities	108,070	76,694
Noncurrent operating lease liabilities	3,006	3,671
Noncurrent debt	35,051	30,212
Total liabilities	146,127	110,577
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 3,000,000 shares authorized; no shares issued and outstanding at December 31, 2023 and 2022
Common stock, $0.001 par value; 1,350,000,000 shares authorized; 544,912,215 and 390,262,524 shares issued and outstanding at December 31, 2023 and 2022, respectively	545	390
Additional paid-in capital	1,844,988	1,493,469
Accumulated deficit	(1,597,769)	(1,413,642)
Accumulated other comprehensive loss	185	(219)
Total stockholders' equity	247,949	79,998
Total liabilities and stockholders' equity	$ 394,076	$ 190,575