Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 618,766	$ 1,115,130
Short-term investments, available-for-sale	583,615	632,516
Accounts receivable, net of allowances of $4,530 and $4,645 at December 31, 2018 and 2017, respectively	688,420	712,535
Inventories, net	21,905	13,912
Prepaid expenses and other current assets	174,195	147,330
Total current assets	2,086,901	2,621,423
Long-term investments, available-for-sale	574,319	984,328
Property and equipment, net	243,396	252,932
Goodwill	1,802,670	1,614,494
Other intangible assets, net	167,187	141,952
Deferred tax assets, net	136,998	152,362
Other assets	124,578	52,685
Total assets	5,136,049	5,820,176
Current liabilities:
Accounts payable	75,551	66,893
Accrued expenses and other current liabilities	290,492	277,679
Income taxes payable	44,409	34,033
Current portion of deferred revenues	1,345,243	1,308,474
Convertible notes, short-term	1,155,445	0
Total current liabilities	2,911,140	1,687,079
Long-term portion of deferred revenues	489,329	555,769
Long-term debt	741,825	2,127,474
Long-term income taxes payable	285,627	335,457
Other liabilities	148,499	121,936
Commitments and contingencies
Temporary equity from Convertible notes	8,110	0
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; 309,761 and 305,751 shares issued and outstanding at December 31, 2018 and 2017, respectively	310	306
Additional paid-in capital	5,404,500	4,883,670
Retained earnings	4,169,019	3,509,484
Accumulated other comprehensive loss	(8,154)	(10,806)
Stockholders' equity before treasury stock	9,565,675	8,382,654
Less - common stock in treasury, at cost (178,327 and 162,044 shares at December 31, 2018 and 2017, respectively)	(9,014,156)	(7,390,193)
Total stockholders' equity	551,519	992,461
Total liabilities, temporary equity and stockholders' equity	$ 5,136,049	$ 5,820,176