Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 326,644	$ 289,473
Marketable securities	542,062	460,088
Accounts receivable, net of reserves of $8,487 and $7,364 at June 30, 2016, and December 31, 2015, respectively	364,401	380,399
Prepaid expenses and other current assets	132,477	123,228
Total current assets	1,365,584	1,253,188
Property and equipment, net	786,835	753,180
Marketable securities	731,232	774,674
Goodwill	1,150,137	1,150,244
Acquired intangible assets, net	142,668	156,095
Deferred income tax assets	2,455	4,700
Other assets	90,811	89,603
Total assets	4,269,722	4,181,684
Current liabilities:
Accounts payable	68,249	61,982
Accrued expenses	234,013	216,166
Deferred revenue	67,163	54,154
Other current liabilities	7,117	138
Total current liabilities	376,542	332,440
Deferred revenue	3,735	4,163
Deferred income tax liabilities	10,248	12,888
Convertible senior notes	628,970	618,047
Other liabilities	99,754	93,268
Total liabilities	1,119,249	1,060,806
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000,000 shares authorized; 700,000 shares designated as Series A Junior Participating Preferred Stock; no shares issued or outstanding	0	0
Common stock, $0.01 par value; 700,000,000 shares authorized; 179,061,970 shares issued and 175,110,207 shares outstanding at June 30, 2016, and 177,212,181 shares issued and outstanding at December 31, 2015	1,791	1,772
Additional paid-in capital	4,508,376	4,437,420
Accumulated other comprehensive loss	(31,616)	(41,453)
Treasury stock, at cost, 3,951,763 shares at June 30, 2016, and no shares at December 31, 2015	(199,710)	0
Accumulated deficit	(1,128,368)	(1,276,861)
Total stockholders’ equity	3,150,473	3,120,878
Total liabilities and stockholders’ equity	$ 4,269,722	$ 4,181,684