CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Total revenues	$ 310,324	$ 268,462	$ 615,541	$ 519,462
Cost of revenues	110,034	103,668	218,120	192,666
Gross profit	200,290	164,794	397,421	326,796
Operating expenses:
Research and development	99,329	87,152	191,534	173,578
Sales and marketing	39,302	35,673	79,399	75,167
General and administrative	19,199	23,635	38,470	40,151
Restructuring and impairment charges	275	1,774	1,178	9,361
Total operating expenses	158,105	148,234	310,581	298,257
Income from operations	42,185	16,560	86,840	28,539
Interest and other, net	2,268	(338)	10,499	(871)
Income before taxes on income	44,453	16,222	97,339	27,668
Provision for (benefit from) taxes on income	6,024	(304)	10,290	(26,701)
Net income	$ 38,429	$ 16,526	$ 87,049	$ 54,369
Net income per share - basic (in USD per share)	$ 0.70	$ 0.31	$ 1.60	$ 1.04
Net income per share - diluted (in USD per share)	$ 0.68	$ 0.30	$ 1.55	$ 1.00
Shares used in computing net income per share:
Basic (in shares)	54,707	52,615	54,469	52,219
Diluted (in shares)	56,480	54,466	56,180	54,149