Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 289,473	$ 238,650
Marketable securities	460,088	519,642
Accounts receivable, net of reserves of $7,364 and $9,023 at December 31, 2015 and 2014, respectively	380,399	329,578
Prepaid expenses and other current assets	123,228	128,981
Deferred income tax assets	0	45,704
Total current assets	1,253,188	1,262,555
Property and equipment, net	753,180	601,591
Marketable securities	774,674	869,992
Goodwill	1,150,244	1,051,294
Acquired intangible assets, net	156,095	132,412
Deferred income tax assets	4,700	1,955
Other assets	95,844	81,747
Total assets	4,187,925	4,001,546
Current liabilities:
Accounts payable	61,982	77,412
Accrued expenses	216,166	204,686
Deferred revenue	54,154	49,679
Other current liabilities	138	2,234
Total current liabilities	332,440	334,011
Deferred revenue	4,163	3,829
Deferred income tax liabilities	12,888	39,299
Convertible senior notes	624,288	604,851
Other liabilities	93,268	74,221
Total liabilities	$ 1,067,047	$ 1,056,211
Commitments and contingencies (Note 10)
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; 177,212,181 shares and 178,300,603 shares issued and outstanding at December 31, 2015 and 2014, respectively	1,772	1,783
Additional paid-in capital	4,437,420	4,559,430
Accumulated other comprehensive loss	(41,453)	(17,611)
Accumulated deficit	(1,276,861)	(1,598,267)
Total stockholders’ equity	3,120,878	2,945,335
Total liabilities and stockholders’ equity	$ 4,187,925	$ 4,001,546