Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 257,448	$ 238,650
Marketable securities	386,055	519,642
Accounts receivable, net of reserves of $11,693 and $9,023 at June 30, 2015, and December 31, 2014, respectively	342,930	329,578
Prepaid expenses and other current assets	119,365	128,981
Deferred income tax assets	45,678	45,704
Total current assets	1,151,476	1,262,555
Property and equipment, net	704,571	601,591
Marketable securities	881,452	869,992
Goodwill	1,135,947	1,051,294
Acquired intangible assets, net	165,730	132,412
Deferred income tax assets	1,890	1,955
Other assets	90,039	81,747
Total assets	4,131,105	4,001,546
Current liabilities:
Accounts payable	85,311	77,412
Accrued expenses	205,373	204,686
Deferred revenue	56,271	49,679
Other current liabilities	1,287	2,234
Total current liabilities	348,242	334,011
Deferred revenue	4,488	3,829
Deferred income tax liabilities	38,833	39,299
Convertible senior notes	614,484	604,851
Other liabilities	79,746	74,221
Total liabilities	$ 1,085,793	$ 1,056,211
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; 180,577,257 shares issued and 178,789,941 shares outstanding at June 30, 2015, and 178,300,603 shares issued and outstanding at December 31, 2014	1,805	1,783
Additional paid-in capital	4,647,275	4,559,430
Accumulated other comprehensive loss	(24,379)	(17,611)
Treasury stock, at cost, 1,787,316 shares at June 30, 2015, and no shares at December 31, 2014	(126,068)	0
Accumulated deficit	(1,453,321)	(1,598,267)
Total stockholders’ equity	3,045,312	2,945,335
Total liabilities and stockholders’ equity	$ 4,131,105	$ 4,001,546