CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue:
Total revenue	$ 343,899	$ 289,418	$ 1,029,664	$ 878,204
Cost of sales:
Amortization	4,762	5,530	14,064	23,403
Total cost of sales	41,365	36,308	116,677	115,796
Gross profit	302,534	253,110	912,987	762,408
Operating expenses:
Selling, general and administrative	120,682	97,576	353,263	280,443
Research and development	73,018	59,019	219,058	174,906
Amortization	3,787	3,491	11,342	10,421
Total operating expenses	197,487	160,086	583,663	465,770
Operating income	105,047	93,024	329,324	296,638
Interest income	3,188	3,213	9,610	7,674
Other income (expense), net	594	(974)	(1,498)	(2,289)
Income before income tax provision	108,829	95,263	337,436	302,023
Income tax provision	19,366	5,927	51,993	35,811
Net income	$ 89,463	$ 89,336	$ 285,443	$ 266,212
Earnings per share - basic:
Earnings per share	$ 1.06	$ 1.06	$ 3.40	$ 3.17
Weighted average shares	84,109	84,158	83,951	84,065
Earnings per share - diluted:
Earnings per share	$ 1.04	$ 1.04	$ 3.34	$ 3.09
Weighted average shares	85,733	86,043	85,570	86,060
Software licenses
Revenue:
Total revenue	$ 137,144	$ 109,103	$ 430,687	$ 350,296
Cost of sales:
Total cost of sales	5,708	4,291	16,620	12,301
Maintenance and service
Revenue:
Total revenue	206,755	180,315	598,977	527,908
Cost of sales:
Total cost of sales	$ 30,895	$ 26,487	$ 85,993	$ 80,092