BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 2,574	$ 17,399
Short-term investments available-for-sale	38,025	26,712
Restricted cash		986
Accounts receivables	907	1,011
Unbilled receivables	1,815	1,570
Prepaid expenses	2,024	2,559
Other current assets	20	171
Total current assets	45,365	50,408
Investments available-for-sale		6,233
Property and equipment, net	13,320	11,456
Goodwill	33,141	33,141
Restricted cash	757	756
Other non-current assets	335	351
Total assets	92,918	102,345
Current liabilities:
Accounts payable	2,946	3,228
Accrued expenses and other current liabilities	7,223	7,275
Deferred revenue		258
Current portion of capital lease	60	58
Current portion of notes payable	571	157
Warrant liability		267
Deferred rent	456	432
Total current liabilities	11,256	11,675
Deferred revenue	2,500	2,500
Non-current portion of capital lease	206	237
Non-current portion of notes payable	1,653	753
Deferred rent	8,077	6,940
Total liabilities	23,692	22,105
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.01 par value, 300,000,000 shares authorized at June 30, 2013 and 200,000,000 shares authorized at December 31, 2012; and 153,165,006 shares issued and 152,709,576 shares outstanding at June 30, 2013 and 148,398,747 shares issued and 147,943,317 shares outstanding at December 31, 2012	1,532	1,484
Additional paid-in capital	450,300	438,939
Accumulated deficit	(380,793)	(358,163)
Treasury stock, 455,430 shares, cost basis	(2,450)	(2,450)
Accumulated other comprehensive income	637	430
Total stockholders' equity	69,226	80,240
Total liabilities and stockholders' equity	$ 92,918	$ 102,345