CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 21,134	$ 29,429
Marketable securities	214,214	275,523
Accounts and other receivables	252	347
Prepaid and other current assets	10,333	12,394
Total current assets	245,933	317,693
Property and equipment, net	4,162	3,747
Operating lease right-of-use assets, net	2,864	4,001
Intangible assets	27,190	27,190
Other assets	107	104
Total assets	280,256	352,735
Current liabilities:
Accounts payable	3,586	3,340
Accrued expenses	18,471	12,835
Current portion of operating lease liabilities	1,547	1,445
Current portion of other long-term liabilities	4,232	990
Total current liabilities	27,836	18,610
Long-term portion of operating lease liabilities	1,299	2,588
Other long-term liabilities	4,403	5,333
Total liabilities	33,538	26,531
Commitments and contingent liabilities
Stockholders' equity:
Convertible preferred stock, $.01 par value; 3,000,000 shares authorized; no shares issued and outstanding at September 30, 2023 and December 31, 2022
Common stock, $.001 par value; 297,000,000 shares authorized; 47,264,197 and 47,200,695 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	47	47
Additional paid-in capital	1,598,591	1,580,829
Accumulated other comprehensive income	2,135	1,260
Accumulated deficit	(1,354,055)	(1,255,932)
Total stockholders' equity	246,718	326,204
Total liabilities and stockholders' equity	$ 280,256	$ 352,735