Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 89,603	$ 206,279
Marketable securities	125,771
Deferred tax assets	3,106	693
Prepaid expenses and other current assets	4,840	5,015
Total current assets	223,320	211,987
Marketable securities	48,446
Property and equipment, net	14,978	10,920
Intangible assets, net	29,159
Goodwill	13,128
Restricted cash and other non-current assets	1,162	1,483
Total assets	330,193	224,390
Current liabilities:
Accounts payable	3,641	4,359
Accrued expenses and other current liabilities	9,677	5,175
Deferred revenue, current portion	25,206	25,340
Total current liabilities	38,524	34,874
Deferred rent, net of current portion	8,724	6,740
Deferred revenue, net of current portion	11,458	30,208
Contingent consideration, net of current portion	6,166
Deferred tax liabilities	3,106	693
Other non-current liabilities	323	208
Total liabilities	68,301	72,723
Commitments and contingencies (Note 5)
Stockholders' equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at September 30, 2014 and December 31, 2013
Common stock, $0.01 par value, 125,000 shares authorized; 28,702 and 23,940 shares issued and outstanding at September 30, 2014 and December 31, 2013, respectively	287	239
Additional paid-in capital	389,519	250,103
Accumulated other comprehensive loss	(74)
Accumulated deficit	(127,840)	(98,675)
Total stockholders' equity	261,892	151,667
Total liabilities and stockholders' equity	$ 330,193	$ 224,390