CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 27,844	$ 20,457
Marketable securities-short term	56,246	60,238
Prepaid expenses and other current assets	5,616	1,119
Total current assets	89,706	81,814
Marketable securities-long term	43,158	2,154
Property and equipment, net	3,243	3,517
Other assets	1,405	1,381
Total assets	137,512	88,866
Current liabilities:
Accounts payable and accrued expenses	26,198	16,836
Note payable	1,700	1,700
Current portion of deferred revenue	33,170	27,825
Current portion of deferred gain on sale leaseback	552	552
Total current liabilities	61,620	46,913
Deferred revenue, net of current portion	48,179	54,627
Deferred gain on sale leaseback, net of current portion	1,611	1,888
Total liabilities	111,410	103,428
Commitments and contingencies
Stockholders' equity (deficit) :
Preferred stock, $0.01 par value; 1,000,000 shares authorized; no shares issued or outstanding
Common stock, $0.01 par value; 100,000,000 shares authorized; 53,700,171 and 44,973,335 shares issued and outstanding at June 30, 2011 and December 31, 2010, respectively	537	450
Additional paid-in capital	436,496	383,713
Accumulated other comprehensive income (loss)	57	(7)
Accumulated deficit	(410,988)	(398,718)
Total stockholders' equity (deficit)	26,102	(14,562)
Total liabilities and stockholders' equity (deficit)	$ 137,512	$ 88,866