Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Product	$ 180,172	$ 162,185	$ 131,507
Professional services	15,621	16,508	14,256
Total revenues	195,793	178,693	145,763
Cost of revenues:
Product	49,816	43,494	37,419
Professional services	22,378	23,179	17,873
Total cost of revenues	72,194	66,673	55,292
Gross profit	123,599	112,020	90,471
Operating expenses:
Research and development	52,818	52,275	55,742
Sales and marketing	78,684	90,141	86,083
General and administrative	26,708	24,633	24,613
Total operating expenses	158,210	167,049	166,438
Loss from operations	(34,611)	(55,029)	(75,967)
Other income (expense), net:
Interest income	277	205	249
Interest expense	(171)	(269)	(314)
Other, net	903	78	(349)
Total other income (expense), net	1,009	14	(414)
Loss before provision for (benefit from) income taxes	(33,602)	(55,015)	(76,381)
Provision for (benefit from) income taxes	1,251	1,138	(1,010)
Net loss	$ (34,853)	$ (56,153)	$ (75,371)
Basic and diluted net loss per share (dollars per share)	$ (0.46)	$ (0.79)	$ (1.12)
Shares used in basic and diluted per share calculations	75,217	70,751	67,381