CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 167,384	$ 32,335
Marketable securities	147,554	135,721
Restricted cash	0	297
Accounts receivable - billed	2,342	7,510
Account receivable - unbilled	2,498	3,100
Prepaid expenses and other current assets	13,201	9,195
Total current assets	332,979	188,158
Property and equipment, net	26,134	19,737
Intangible assets, net	11,360	12,577
Goodwill	53,307	54,612
Other non-current assets	918	918
Total assets	424,698	276,002
Current liabilities:
Accounts payable	7,117	12,908
Accrued expenses	16,522	19,397
Current portion of notes payable	532	603
Deferred rent	1,187	1,138
Other current liabilities	1,695	70
Total current liabilities	27,053	34,116
Deferred revenue	2,500	2,500
Non-current portion of notes payable	149	395
Deferred rent	7,320	7,734
Other non-current liabilities	73	1,639
Total liabilities	37,095	46,384
Commitments and contingences	0	0
Stockholders’ equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares issued and outstanding as of June 30, 2015 and December 31, 2014, respectively	0	0
Common stock, $0.01 par value, 600,000,000 shares authorized at June 30, 2015 and 300,000,000 shares authorized at December 31, 2014; 269,095,405 shares issued and 268,639,975 shares outstanding at June 30, 2015 and 239,287,294 shares issued and 238,831,864 shares outstanding at December 31, 2014	2,691	2,393
Additional paid-in capital	934,176	729,373
Accumulated deficit	(538,104)	(493,093)
Treasury stock, 455,430 shares, cost basis at both June 30, 2015 and December 31, 2014	(2,450)	(2,450)
Accumulated other comprehensive loss	(8,710)	(6,605)
Total stockholders’ equity	387,603	229,618
Total liabilities and stockholders’ equity	$ 424,698	$ 276,002