Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 738,462	$ 1,036,455
Marketable securities	831,749	855,650
Accounts receivable, net of reserves of $1,745 and $1,534 at September 30, 2019, and December 31, 2018, respectively	516,657	479,889
Prepaid expenses and other current assets	167,040	163,360
Total current assets	2,253,908	2,535,354
Marketable securities	734,116	209,066
Property and equipment, net	1,079,914	910,618
Operating lease right-of-use assets	349,155
Acquired intangible assets, net	166,407	168,348
Goodwill	1,583,479	1,487,404
Deferred income tax assets	39,321	34,913
Other assets	151,134	116,067
Total assets	6,357,434	5,461,770
Current liabilities:
Accounts payable	108,187	99,089
Accrued expenses	304,333	328,304
Deferred revenue	98,842	69,083
Convertible senior notes	0	686,552
Operating lease liabilities	86,959
Other current liabilities	4,202	27,681
Total current liabilities	602,523	1,210,709
Deferred revenue	4,526	4,557
Deferred income tax liabilities	21,797	19,624
Convertible senior notes	1,823,448	874,080
Operating lease liabilities	296,750
Other liabilities	106,790	160,940
Total liabilities	2,855,834	2,269,910
Commitments and contingencies (Note 8)
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; 165,211,770 shares issued and 161,659,502 shares outstanding at September 30, 2019, and 162,904,550 shares issued and outstanding at December 31, 2018	1,652	1,629
Additional paid-in capital	3,919,264	3,670,033
Accumulated other comprehensive loss	(56,424)	(48,912)
Treasury stock, at cost, 3,552,268 shares at September 30, 2019, and no shares at December 31, 2018	(291,788)	0
Accumulated deficit	(71,104)	(430,890)
Total stockholders’ equity	3,501,600	3,191,860
Total liabilities and stockholders’ equity	$ 6,357,434	$ 5,461,770