Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
REVENUE:
Total revenue	$ 576.9	$ 472.6
COST OF REVENUE:
Total cost of revenue	128.7	113.0
GROSS PROFIT:
Total gross profit	448.2	359.6
OPERATING EXPENSES:
Research and development	80.3	68.6
Sales and marketing	260.0	215.9
General and administrative	28.8	24.5
Gain on intellectual property matter	(36.8)	0.0
Total operating expenses	332.3	309.0
OPERATING INCOME	115.9	50.6
INTEREST INCOME—NET	9.2	10.2
OTHER EXPENSE—NET	(8.0)	(0.5)
INCOME BEFORE INCOME TAXES	117.1	60.3
PROVISION FOR INCOME TAXES	13.1	1.5
NET INCOME	$ 104.0	$ 58.8
Net income per share (Note 8):
Basic (in dollars per share)	$ 0.61	$ 0.35
Diluted (in dollars per share)	$ 0.60	$ 0.34
Weighted-average shares outstanding:
Basic (in shares)	170.6	170.2
Diluted (in shares)	174.2	174.8
Product [Member]
REVENUE:
Total revenue	$ 192.3	$ 162.7
COST OF REVENUE:
Total cost of revenue	76.3	70.2
GROSS PROFIT:
Total gross profit	116.0	92.5
Service [Member]
REVENUE:
Total revenue	384.6	309.9
COST OF REVENUE:
Total cost of revenue	52.4	42.8
GROSS PROFIT:
Total gross profit	$ 332.2	$ 267.1