Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Cash and cash equivalents	$ 16,766	$ 10,784
Marketable securities	67,366	49,501
Interest receivable	331	337
Accounts receivable	919	366
Prepaid expenses	310	326
Total current assets	85,692	61,314
Property and equipment, net	1,603	1,673
Other assets	41	12
Total assets	87,336	62,999
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued liabilities	5,515	5,654
Accrued compensation and employee benefits	1,672	1,357
Deferred revenue	17	81
Total current liabilities	7,204	7,092
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value; 80,000,000 shares authorized, 52,554,795 and 45,377,739 shares issued and outstanding at December 31, 2011 and 2010, respectively	526	454
Additional paid-in capital	332,839	272,954
Accumulated deficit	(253,245)	(217,495)
Accumulated other comprehensive income / (loss)	12	(6)
Total stockholders' equity	80,132	55,907
Total liabilities and stockholders' equity	$ 87,336	$ 62,999