CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 28,401	$ 39,143
Marketable securities	328,416	369,107
Accounts and other receivables	97	172
Prepaid and other current assets	11,065	2,417
Total current assets	367,979	410,839
Property and equipment, net	3,744	3,551
Operating lease right-of-use assets, net	3,944	2,970
Intangible assets, net	27,190	27,190
Other assets	104	104
Total assets	402,961	444,654
Current liabilities:
Accounts payable	902	1,228
Accrued expenses	11,229	12,000
Litigation settlement payable	15,000
Current portion of operating lease liabilities	1,425	1,746
Current portion of other long-term liabilities	1,393	1,554
Total current liabilities	29,949	16,528
Long-term portion of operating lease liabilities	2,586	1,296
Other long-term liabilities	5,333	7,354
Total liabilities	37,868	25,178
Commitments and contingent liabilities
Stockholders' equity:
Convertible preferred stock, $.01 par value; 3,000,000 shares authorized; no shares issued and outstanding at June 30, 2022 and December 31, 2021
Common stock, $.001 par value; 297,000,000 shares authorized; 46,764,703 and 46,730,198 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively	47	47
Additional paid-in capital	1,568,124	1,561,142
Accumulated other comprehensive income	(417)	1,894
Accumulated deficit	(1,202,661)	(1,143,607)
Total stockholders' equity	365,093	419,476
Total liabilities and stockholders' equity	$ 402,961	$ 444,654