CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
ASSETS
Cash and cash equivalents	$ 437,661	$ 478,750
Accounts receivable	1,190	4,467
Unbilled receivable	3,643	2,345
Contract assets	3,000	3,000
Non-cash royalty receivable	2,417	4,115
Prepaid and other current assets	8,807	7,322
Total current assets	456,718	499,999
Property and equipment, net of accumulated depreciation	4,431	4,663
Operating lease right-of-use assets	11,888	12,392
Other assets	8,672	8,711
Total assets	481,709	525,765
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable	16,060	18,434
Accrued compensation	3,408	5,469
Other accrued liabilities	28,730	23,077
Current portion of liability related to the sale of future royalties, net of deferred financing costs of $199 and $198, respectively	8,741	6,077
Current portion of operating lease liability	3,762	3,537
Current portion of deferred revenue	23,417	44,351
Total current liabilities	84,118	100,945
Deferred revenue, net of current portion	46,694	47,717
Operating lease liability, net of current portion	14,263	15,244
Liability related to the sale of future royalties, net of current portion and deferred financing costs of $323 and $381, respectively	29,490	34,967
Other long-term liabilities	676	1,306
Total liabilities	175,241	200,179
Commitments and contingencies (Note H)
Shareholders' equity:
Preferred stock, $.01 par value; authorized 5,000 shares; no shares issued and outstanding as of each of March 31, 2022 and December 31, 2021
Common stock, $.01 par value; authorized 300,000 shares; 220,536 and 220,361 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively	2,205	2,204
Additional paid-in capital	1,799,551	1,794,525
Accumulated deficit	(1,495,288)	(1,471,143)
Total shareholders' equity	306,468	325,586
Total liabilities and shareholders' equity	$ 481,709	$ 525,765