CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 138,144	$ 32,335
Marketable securities	152,042	135,721
Restricted cash	0	297
Accounts receivable - billed	2,197	7,510
Account receivable - unbilled	2,137	3,100
Prepaid expenses and other current assets	15,582	9,195
Total current assets	310,102	188,158
Property and equipment, net	29,421	19,737
Intangible assets, net	11,005	12,577
Goodwill	53,062	54,612
Other non-current assets	1,044	918
Total assets	404,634	276,002
Current liabilities:
Accounts payable	8,201	12,908
Accrued expenses	13,270	19,397
Current portion of notes payable	493	603
Deferred rent	1,212	1,138
Other current liabilities	1,697	70
Total current liabilities	24,873	34,116
Deferred revenue	2,500	2,500
Non-current portion of notes payable	45	395
Deferred rent	7,106	7,734
Other non-current liabilities	3,094	1,639
Total liabilities	37,618	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 September 30, 2015 and December 31, 2014, respectively	0	0
Common stock, $0.01 par value, 600,000,000 shares authorized at September 30, 2015 and 300,000,000 shares authorized at December 31, 2014; 270,274,501 shares issued and 269,819,071 shares outstanding at September 30, 2015 and 239,287,294 shares issued and 238,831,864 shares outstanding at December 31, 2014	2,703	2,393
Additional paid-in capital	947,055	729,373
Accumulated deficit	(571,224)	(493,093)
Treasury stock, 455,430 shares, cost basis at both September 30, 2015 and December 31, 2014	(2,450)	(2,450)
Accumulated other comprehensive loss	(9,068)	(6,605)
Total stockholders’ equity	367,016	229,618
Total liabilities and stockholders’ equity	$ 404,634	$ 276,002