UNAUDITED 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
Revenue
Total revenue	[1]	$ 203,263	$ 190,957	$ 635,224	$ 633,862
Cost of revenue
Total cost of revenue	[1]	74,423	69,731	223,854	205,696
Gross profit	[1]	128,840	121,226	411,370	428,166
Operating expenses
Selling and marketing	[1]	87,490	69,363	269,845	214,244
Research and development	[1]	46,504	41,031	135,261	121,089
General and administrative	[1]	12,104	13,133	38,749	38,174
Total operating expenses	[1]	146,098	123,527	443,855	373,507
(Loss) income from operations	[1]	(17,258)	(2,301)	(32,485)	54,659
Foreign currency transaction gain (loss)	[1]	399	(5,052)	558	(6,549)
Interest income, net	[1]	683	140	2,076	547
Other income, net	[1]			363	287
(Loss) income before benefit from income taxes	[1]	(16,176)	(7,213)	(29,488)	48,944
Benefit from income taxes	[1]	(8,589)	(8,501)	(23,692)	(9,009)
Net (loss) income	[1]	$ (7,587)	$ 1,288	$ (5,796)	$ 57,953
(Loss) earnings per share
Basic	[1]	$ (0.10)	$ 0.01	$ (0.07)	$ 0.75
Diluted	[1]	$ (0.10)	$ 0.01	$ (0.07)	$ 0.70
Weighted-average number of common shares outstanding
Basic	[1]	78,700	77,691	78,525	77,258
Diluted	[1]	78,700	83,323	78,525	82,717
Cash dividends declared per share	[1]	$ 0.03	$ 0.03	$ 0.09	$ 0.09
Software license
Revenue
Total revenue	[1]	$ 52,342	$ 53,234	$ 184,899	$ 231,392
Cost of revenue
Total cost of revenue	[1]	1,255	1,276	3,772	3,826
Maintenance
Revenue
Total revenue	[1]	66,017	61,812	196,448	179,949
Cost of revenue
Total cost of revenue	[1]	6,079	6,716	18,035	20,945
Services
Revenue
Total revenue	[1]	84,904	75,911	253,877	222,521
Cost of revenue
Total cost of revenue	[1]	$ 67,089	$ 61,739	$ 202,047	$ 180,925

[1] On January 1, 2018, the Company adopted the ASC 606 revenue recognition standard and has adjusted prior periods to conform. See Note 2. "New Accounting Pronouncements" for additional information.