Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 593,299	$ 347,845
Marketable securities	217,208	125,710
Deferred tax assets	399	1,913
Prepaid expenses and other current assets	4,546	4,521
Total current assets	815,452	479,989
Marketable securities	125,938	18,448
Property and equipment, net	16,803	15,740
Intangible assets, net	26,337	28,219
Goodwill	13,128	13,128
Restricted cash and other non-current assets	1,511	1,215
Total assets	999,169	556,739
Current liabilities:
Accounts payable	2,339	2,954
Accrued expenses and other current liabilities	20,024	14,649
Deferred revenue, current portion	5,670	25,375
Total current liabilities	28,033	42,978
Deferred rent, net of current portion	8,223	8,674
Deferred revenue, net of current portion	38,724	5,302
Contingent consideration, net of current portion	4,590	6,321
Deferred tax liabilities	399	1,913
Other non-current liabilities	234	294
Total liabilities	$ 80,203	$ 65,482
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at June 30, 2015 and December 31, 2014
Common stock, $0.01 par value, 125,000 shares authorized; 35,958 and 32,340 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 360	$ 323
Additional paid-in capital	1,142,625	638,389
Accumulated other comprehensive loss	(53)	(71)
Accumulated deficit	(223,966)	(147,384)
Total stockholders' equity	918,966	491,257
Total liabilities and stockholders' equity	$ 999,169	$ 556,739