CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 32,335	$ 119,471
Marketable securities	135,721	13,597
Restricted cash	297	1,417
Accounts receivable - billed	7,510	1,911
Accounts receivable - unbilled	3,100	4,988
Prepaid expenses and other current assets	9,195	3,617
Total current assets	188,158	145,001
Property and equipment, net	19,737	14,251
Intangible assets, net	12,577	16,250
Goodwill	54,612	58,707
Other non-current assets	918	916
Total assets	276,002	235,125
Current liabilities:
Accounts payable	12,908	5,985
Accrued expenses	19,397	10,411
Current portion of notes payable	603	877
Deferred rent	1,138	470
Other current liabilities	70	379
Total current liabilities	34,116	18,122
Deferred revenue	2,500	2,500
Non-current portion of notes payable	395	1,004
Deferred rent	7,734	8,502
Other non-current liabilities	1,639	1,763
Total liabilities	46,384	31,891
Commitments and contingencies	0	0
Stockholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.01 par value, 300,000,000 shares authorized at December 31, 2014 and 2013; and 239,287,294 shares issued and 238,831,864 shares outstanding at December 31, 2014 and 209,110,744 shares issued and 208,655,314 shares outstanding at December 31, 2013	2,393	2,091
Additional paid-in capital	729,373	612,900
Accumulated deficit	(493,093)	(410,146)
Treasury stock, 455,430 shares, cost basis	(2,450)	(2,450)
Accumulated other comprehensive income (loss)	(6,605)	839
Total stockholders' equity	229,618	203,234
Total liabilities and stockholders' equity	$ 276,002	$ 235,125