CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue		$ 74,200	$ 48,227	$ 142,659	$ 90,461
Cost of revenue	[1]	22,936	16,162	44,452	30,452
Gross profit		51,264	32,065	98,207	60,009
Operating expenses:
Research and development	[1]	22,134	14,227	43,731	27,485
Sales and marketing	[1]	39,350	27,242	75,522	50,645
General and administrative	[1]	16,076	11,536	31,937	21,663
Total operating expenses	[1]	77,560	53,005	151,190	99,793
Operating loss		(26,296)	(20,940)	(52,983)	(39,784)
Other income (expense), net		134	(343)	64	(574)
Loss before provision for income taxes		(26,162)	(21,283)	(52,919)	(40,358)
Provision for income taxes		92	199	506	292
Net loss		$ (26,254)	$ (21,482)	$ (53,425)	$ (40,650)
Net loss per share, basic and diluted (usd per share)		$ (0.28)	$ (0.25)	$ (0.58)	$ (0.50)
Weighted-average shares used to compute basic and diluted net loss per share (in shares)		92,174	86,390	91,351	81,390

[1] (1) Includes share-based compensation expense as follows: Three Months EndedJune 30, Six Months EndedJune 30,2016 2015 2016 2015Cost of revenue$1,802 $1,114 $3,435 $2,004Research and development6,749 4,446 13,376 8,510Sales and marketing5,684 3,937 11,123 6,369General and administrative4,410 3,890 8,407 6,731