Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Product	$ 181,119	$ 146,381	$ 141,913
Service	148,823	106,210	107,121
Total revenue	329,942	252,591	249,034
Cost of revenue:
Product	70,250	47,367	50,460
Service	58,196	37,613	36,917
Total cost of revenue	128,446	84,980	87,377
Gross profit	201,496	167,611	161,657
Operating expenses:
Research and development	101,481	72,841	77,908
Sales and marketing	83,403	68,539	72,841
General and administrative	47,642	35,948	39,846
Acquisition- and integration-related	14,763	1,152	131
Restructuring	9,436	2,740	2,148
Total operating expenses	256,725	181,220	192,874
Loss from operations	(55,229)	(13,609)	(31,217)
Interest income, net	263	769	207
Other income, net	1,274	1,424	1,122
Loss before income taxes	(53,692)	(11,416)	(29,888)
Income tax benefit (provision)	18,440	(2,516)	(2,007)
Net loss	$ (35,252)	$ (13,932)	$ (31,895)
Loss per share:
Basic (in dollars per share)	$ (0.60)	$ (0.28)	$ (0.64)
Diluted (in dollars per share)	$ (0.60)	$ (0.28)	$ (0.64)
Shares used to compute loss per share:
Basic (in shares)	58,822	49,385	49,560
Diluted (in shares)	58,822	49,385	49,560