CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ASSETS
Cash and cash equivalents	$ 283,120	$ 293,856
Accounts receivable	93	35
Unbilled receivable	5,405	11
Non-cash royalty receivable	15,533	22,451
Prepaid and other current assets	15,421	7,901
Total current assets	319,572	324,254
Property and equipment, net of accumulated depreciation	5,417	5,760
Operating lease right-of-use assets	13,648	14,072
Other assets	7,325	10,986
Total assets	345,962	355,072
LIABILITIES AND SHAREHOLDERS? EQUITY
Accounts payable	12,916	9,538
Accrued compensation	2,882	4,620
Other accrued liabilities	32,820	29,320
Convertible 4.5% senior notes, net of deferred financing costs of $4 and $7, respectively	2,096	2,093
Current portion of liability related to the sale of future royalties, net of deferred financing costs of $267 and $319, respectively	29,007	44,357
Current portion of operating lease liability	3,117	3,146
Current portion of deferred revenue	51,515	29,249
Total current liabilities	134,353	122,323
Deferred revenue, net of current portion	58,522	80,860
Operating lease liability, net of current portion	17,878	18,651
Liability related to the sale of future royalties, net of current portion and deferred financing costs of $525 and $584, respectively	38,609	41,082
Other long-term liabilities	2,480	2,586
Total liabilities	251,842	265,502
Commitments and contingencies (Note I)
Shareholders? deficit:
Preferred stock, $.01 par value; authorized 5,000 shares; no shares issued and outstanding as of each of March 31, 2021 and December 31, 2020
Common stock, $.01 par value; authorized 300,000 shares; issued and outstanding 199,941 and 194,998 shares as of March 31, 2021 and December 31, 2020, respectively	1,999	1,950
Additional paid-in capital	1,458,012	1,419,460
Accumulated deficit	(1,365,891)	(1,331,840)
Total shareholders equity	94,120	89,570
Total liabilities and shareholders? equity	$ 345,962	$ 355,072