CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net revenues	$ 505,289	$ 385,267	$ 1,432,472	$ 1,052,090
Cost of net revenues	133,508	92,779	367,701	253,060
Gross profit	371,781	292,488	1,064,771	799,030
Operating expenses:
Selling, general and administrative	213,873	169,524	625,585	483,636
Research and development	32,700	24,201	93,095	71,389
Total operating expenses	246,573	193,725	718,680	555,025
Income from operations	125,208	98,763	346,091	244,005
Interest income	2,234	1,826	6,327	4,462
Other income (expense), net	(837)	1,924	(7,759)	4,145
Net income before provision for income taxes and equity in losses of investee	126,605	102,513	344,659	252,612
Provision for income taxes	24,601	18,344	35,206	26,508
Equity in losses of investee, net of tax	1,132	1,614	6,610	4,950
Net income	$ 100,872	$ 82,555	$ 302,843	$ 221,154
Net income per share:
Basic (in usd per share)	$ 1.26	$ 1.03	$ 3.78	$ 2.76
Diluted (in usd per share)	$ 1.24	$ 1.01	$ 3.71	$ 2.71
Shares used in computing net income per share:
Basic (in shares)	80,111	80,163	80,122	80,086
Diluted (in shares)	81,359	81,789	81,538	81,757