CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 31,325	$ 34,871
Restricted cash	364	364
Marketable securities	135,345	148,851
Interest and other receivables	5,239	1,763
Prepaid and other current assets	3,651	1,357
Total current assets	175,924	187,206
Noncurrent marketable securities	10,945	28,651
Property and equipment, net	643	650
Operating leases, right-of-use assets	4,586	4,727
Deposits and other assets	6,323	4,800
Total assets	198,421	226,034
Current liabilities:
Accounts payable	6,245	6,687
Accrued compensation and benefits	3,682	8,099
Operating lease liabilities	907	901
Accrued liabilities	35,796	29,834
Total current liabilities	46,630	45,521
Noncurrent operating lease liabilities	4,125	4,267
Noncurrent debt	50,179	49,830
Commitments and contingencies
Stockholders' equity:
Common stock	324	324
Additional paid-in capital	1,399,713	1,398,006
Accumulated deficit	(1,301,839)	(1,271,741)
Accumulated other comprehensive loss	(711)	(173)
Total stockholders' equity	97,487	126,416
Total liabilities and stockholders' equity	$ 198,421	$ 226,034