Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Revenue	$ 31,403	$ 22,973	$ 17,800
Costs and expenses:
Cost of revenue	15,009	12,361	9,777
Research and development	14,979	11,635	8,990
Selling, general and administrative	29,912	15,486	9,529
Total costs and expenses	59,900	39,482	28,296
Loss from operations	(28,497)	(16,509)	(10,496)
Other income (expense):
Interest income	68	21	10
Interest expense	(1,942)	(804)	(599)
Other income (expense)	(66)	(29)	80
Revaluation of preferred stock warrant liability	1,156	(387)	73
Total other income (expense)	(784)	(1,199)	(436)
Net loss	(29,281)	(17,708)	(10,932)
Accretion of mandatorily redeemable convertible preferred stock	(4,653)	(7,533)	(5,251)
Net loss attributable to common stockholders	$ (33,934)	$ (25,241)	$ (16,183)
Net loss per share-basic and diluted	$ (4.44)	$ (71.10)	$ (50.10)
Weighted average shares used in computing basic and diluted net loss per share	7,643	355	323