Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 324,169	$ 289,473
Marketable securities	512,849	460,088
Accounts receivable, net of reserves of $6,145 and $7,364 at December 31, 2016 and 2015, respectively	368,596	380,399
Prepaid expenses and other current assets	104,303	123,228
Total current assets	1,309,917	1,253,188
Property and equipment, net	801,017	753,180
Marketable securities	779,311	774,674
Goodwill	1,228,503	1,150,244
Acquired intangible assets, net	149,463	156,095
Deferred income tax assets	8,982	4,700
Other assets	95,953	89,603
Total assets	4,373,146	4,181,684
Current liabilities:
Accounts payable	76,120	61,982
Accrued expenses	238,777	216,166
Deferred revenue	52,972	54,154
Other current liabilities	6,719	138
Total current liabilities	374,588	332,440
Deferred revenue	3,758	4,163
Deferred income tax liabilities	11,652	12,888
Convertible senior notes	640,087	618,047
Other liabilities	118,691	93,268
Total liabilities	1,148,776	1,060,806
Commitments and contingencies (Note 11)
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; 173,254,797 and 177,212,181 shares issued and outstanding at December 31, 2016 and 2015, respectively	1,733	1,772
Additional paid-in capital	4,239,588	4,437,420
Accumulated other comprehensive loss	(56,222)	(41,453)
Accumulated deficit	(960,729)	(1,276,861)
Total stockholders’ equity	3,224,370	3,120,878
Total liabilities and stockholders’ equity	$ 4,373,146	$ 4,181,684