CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Software license	$ 288,334	$ 279,995	$ 275,588
Maintenance	244,347	220,336	202,802
Services	307,901	249,935	204,305
Total revenue	840,582	750,266	682,695
Cost of revenue:
Software license	5,085	4,943	4,125
Maintenance	27,905	25,505	21,903
Services	246,683	208,808	187,418
Total cost of revenue	279,673	239,256	213,446
Gross profit	560,909	511,010	469,249
Operating expenses:
Selling and marketing	307,210	278,849	241,387
Research and development	162,886	145,548	126,374
General and administrative	52,153	45,951	36,738
Acquisition-related		2,903	89
Total operating expenses	522,249	473,251	404,588
Income from operations	38,660	37,759	64,661
Foreign currency transaction (loss)/gain	(900)	2,247	(4,168)
Interest income, net	731	776	1,056
Other expense, net	(1,391)	(5,580)	(1,044)
Income before provision for income taxes	37,100	35,202	60,505
Provision for income taxes	4,166	8,216	24,183
Net income	$ 32,934	$ 26,986	$ 36,322
Earnings per share:
Basic	$ 0.43	$ 0.35	$ 0.47
Diluted	$ 0.40	$ 0.34	$ 0.46
Weighted-average number of common shares outstanding:
Basic	77,431	76,343	76,507
Diluted	82,832	79,732	79,043