Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 545,761	$ 618,766
Short-term investments, available-for-sale	43,055	583,615
Accounts receivable, net of allowances of $9,557 and $4,530 at December 31, 2019 and 2018, respectively	720,359	688,420
Inventories, net	15,898	21,905
Prepaid expenses and other current assets	187,659	174,195
Total current assets	1,512,732	2,086,901
Long-term investments, available-for-sale	16,640	574,319
Property and equipment, net	231,894	243,396
Operating lease right-of-use assets	206,154
Goodwill	1,798,408	1,802,670
Other intangible assets, net	108,478	167,187
Deferred tax assets, net	361,814	136,998
Other assets	152,806	124,578
Total assets	4,388,926	5,136,049
Current liabilities:
Accounts payable	84,538	75,551
Accrued expenses and other current liabilities	331,680	290,492
Income taxes payable	60,036	44,409
Current portion of deferred revenues	1,352,333	1,345,243
Convertible notes, short-term	0	1,155,445
Total current liabilities	1,828,587	2,911,140
Long-term portion of deferred revenues	443,458	489,329
Long-term debt	742,926	741,825
Long-term income taxes payable	259,391	285,627
Operating lease liabilities	209,382
Other liabilities	67,526	148,499
Commitments and contingencies
Temporary equity from Convertible notes	0	8,110
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; 318,760 and 309,761 shares issued and outstanding at December 31, 2019 and 2018, respectively	319	310
Additional paid-in capital	6,249,065	5,404,500
Retained earnings	4,660,145	4,169,019
Accumulated other comprehensive loss	(5,127)	(8,154)
Stockholders' equity before treasury stock	10,904,402	9,565,675
Less - common stock in treasury, at cost (188,693 and 178,327 shares at December 31, 2019 and 2018, respectively)	(10,066,746)	(9,014,156)
Total stockholders' equity	837,656	551,519
Total liabilities, temporary equity and stockholders' equity	$ 4,388,926	$ 5,136,049