CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 31,537	$ 9,925
Restricted cash	363	363
Marketable securities	179,490	186,350
Interest and other receivables	759	722
Prepaid and other current assets	3,115	2,497
Total current assets	215,264	199,857
Noncurrent marketable securities	33,289	63,387
Property and equipment, net	620	658
Operating leases, right-of-use assets	5,163	5,295
Deposits and other assets	4,272	1,531
Total assets	258,608	270,728
Current liabilities:
Accounts payable	4,459	6,919
Accrued compensation and benefits	3,446	8,218
Operating lease liabilities	883	878
Accrued liabilities	19,764	14,925
Total current liabilities	28,552	30,940
Noncurrent operating lease liabilities	4,672	4,799
Noncurrent debt	24,222	24,042
Commitments and contingencies
Stockholders' equity:
Common stock	318	310
Additional paid-in capital	1,384,262	1,366,188
Accumulated deficit	(1,183,453)	(1,155,629)
Accumulated other comprehensive gain	35	78
Total stockholders' equity	201,162	210,947
Total liabilities and stockholders' equity	$ 258,608	$ 270,728