CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 47,820	$ 70,105
Accounts receivable	2,096	1,516
Other current assets	1,061	919
Total current assets	50,977	72,540
Auction rate securities	3,240	3,332
Fixed assets, at cost, net of accumulated depreciation and amortization	3,915	4,038
Other assets	200	200
Total assets	58,332	80,110
Current liabilities:
Accounts payable and accrued expenses	3,983	6,331
Deferred revenue - current	204	204
Other current liabilities	115	115
Total current liabilities	4,302	6,650
Deferred revenue - long term	60	162
Other liabilities	999	1,497
Total liabilities	5,361	8,309
Commitments and contingencies (Note 8)
Stockholders' equity:
Common stock	44	44
Additional paid-in capital	468,408	463,440
Accumulated deficit	(412,480)	(388,674)
Accumulated other comprehensive loss	(260)	(268)
Treasury Stock	(2,741)	(2,741)
Total stockholders' equity	52,971	71,801
Total liabilities and stockholders' equity	$ 58,332	$ 80,110