CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 29,036	$ 9,925
Restricted cash	363	363
Marketable securities	147,084	186,350
Interest and other receivables	610	722
Prepaid and other current assets	2,262	2,497
Total current assets	179,355	199,857
Noncurrent marketable securities	39,362	63,387
Property and equipment, net	608	658
Operating leases, right-of-use assets	4,892	5,295
Deposits and other assets	4,880	1,531
Total assets	229,097	270,728
Current liabilities:
Accounts payable	4,714	6,919
Accrued compensation and benefits	6,615	8,218
Operating lease liabilities	895	878
Accrued liabilities	26,246	14,925
Total current liabilities	38,470	30,940
Noncurrent operating lease liabilities	4,405	4,799
Noncurrent debt	34,669	24,042
Commitments and contingencies
Stockholders' equity:
Common stock	321	310
Additional paid-in capital	1,390,940	1,366,188
Accumulated deficit	(1,239,724)	(1,155,629)
Accumulated other comprehensive gain	16	78
Total stockholders' equity	151,553	210,947
Total liabilities and stockholders' equity	$ 229,097	$ 270,728