CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 54,123	$ 29,429
Marketable securities	224,264	275,523
Accounts and other receivables	1,314	347
Prepaid and other current assets	9,896	12,394
Total current assets	289,597	317,693
Property and equipment, net	3,995	3,747
Operating lease right-of-use assets, net	3,633	4,001
Intangible assets	27,190	27,190
Other assets	104	104
Total assets	324,519	352,735
Current liabilities:
Accounts payable	3,374	3,340
Accrued expenses	9,374	12,835
Current portion of operating lease liabilities	1,493	1,445
Current portion of other long-term liabilities	978	990
Total current liabilities	15,219	18,610
Long-term portion of operating lease liabilities	2,157	2,588
Other long-term liabilities	4,403	5,333
Total liabilities	21,779	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 March 31, 2023 and December 31, 2022		0
Common stock, $.001 par value; 297,000,000 shares authorized; 47,244,681 and 47,200,695 shares issued and outstanding at March 31, 2023 and December 31, 2022, respectively	47	47
Additional paid-in capital	1,585,863	1,580,829
Accumulated other comprehensive income	2,123	1,260
Accumulated deficit	(1,285,293)	(1,255,932)
Total stockholders' equity	302,740	326,204
Total liabilities and stockholders' equity	$ 324,519	$ 352,735