Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements of Operations [Abstract]
Revenue	$ 15,926	$ 10,322	$ 43,168	$ 27,007
Cost of revenue	6,109	4,261	16,420	11,710
Gross profit	9,817	6,061	26,748	15,297
Operating expenses:
Research and development	4,336	3,008	12,046	7,981
General and administrative	1,841	879	4,719	2,912
Sales and marketing	11,078	8,869	27,436	25,333
Total operating expenses	17,255	12,756	44,201	36,226
Loss from operations	(7,438)	(6,695)	(17,453)	(20,929)
Interest and other income, net	22	37	48	158
Net loss	(7,416)	(6,658)	(17,405)	(20,771)
Accretion of redeemable convertible preferred stock	(23)	(53)	(128)	(158)
Net loss attributable to common stockholders	$ (7,439)	$ (6,711)	$ (17,533)	$ (20,929)
Basic and diluted net loss per share attributable to common stockholders	$ (0.47)	$ (1.52)	$ (2.01)	$ (4.77)
Weighted average number of shares of common stock used in computing basic and diluted net loss per share	15,955,532	4,414,373	8,707,865	4,383,615

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