Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,021,708	$ 1,115,130
Short-term investments, available-for-sale	487,367	632,516
Accounts receivable, net of allowances of $3,737 and $4,645 at June 30, 2018 and December 31, 2017, respectively	528,386	712,535
Inventories, net	20,282	13,912
Prepaid expenses and other current assets	208,648	147,330
Total current assets	2,266,391	2,621,423
Long-term investments, available-for-sale	825,444	984,328
Property and equipment, net	246,025	252,932
Goodwill	1,662,438	1,614,494
Other intangible assets, net	141,989	141,952
Deferred tax assets, net	119,760	152,362
Other assets	104,015	52,685
Total assets	5,366,062	5,820,176
Current liabilities:
Accounts payable	86,533	66,893
Accrued expenses and other current liabilities	277,275	277,679
Income taxes payable	1,261	34,033
Current portion of convertible notes	1,406,157	0
Current portion of deferred revenues	1,243,032	1,308,474
Total current liabilities	3,014,258	1,687,079
Long-term portion of deferred revenues	480,942	555,769
Long-term debt	741,277	2,127,474
Long-term income taxes payable	321,651	335,457
Other liabilities	143,677	121,936
Commitments and contingencies
Temporary equity from convertible notes	28,081	0
Stockholders' equity:
Preferred stock at $.01 par value: 5,000 shares authorized, none issued and outstanding	0	0
Common stock at $.001 par value: 1,000,000 shares authorized; 307,662 and 305,751 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	308	306
Additional paid-in capital	5,116,339	4,883,670
Retained earnings	3,893,354	3,509,484
Accumulated other comprehensive loss	(18,718)	(10,806)
Stockholders' equity before treasury stock	8,991,283	8,382,654
Less - common stock in treasury, at cost (172,244 and 162,044 shares at June 30, 2018 and December 31, 2017, respectively)	(8,355,107)	(7,390,193)
Total stockholders' equity	636,176	992,461
Total liabilities, temporary equity and stockholders' equity	$ 5,366,062	$ 5,820,176