Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue:
Product and service	$ 11,264	$ 8,389	$ 30,278	$ 21,283
Collaboration	1,079	0	1,697	0
Total revenue	12,343	8,389	31,975	21,283
Costs and expenses:
Cost of product and service revenue	5,271	3,784	14,456	10,188
Research and development	5,961	3,784	15,967	10,469
Selling, general and administrative	12,515	7,988	36,069	20,822
Total costs and expenses	23,747	15,556	66,492	41,479
Loss from operations	(11,404)	(7,167)	(34,517)	(20,196)
Other income (expense):
Interest income	65	22	204	28
Interest expense	(697)	(538)	(3,248)	(1,412)
Other expense	(112)	(17)	(97)	(30)
Revaluation of preferred stock warrant liability	0	0	0	1,156
Total other income (expense)	(744)	(533)	(3,141)	(258)
Net loss	(12,148)	(7,700)	(37,658)	(20,454)
Accretion of mandatorily redeemable convertible preferred stock	0	0	0	(4,653)
Net loss attributable to common stockholders	$ (12,148)	$ (7,700)	$ (37,658)	$ (25,107)
Net loss per share - basic and diluted	$ (0.67)	$ (0.53)	$ (2.13)	$ (4.74)
Shares used in computing basic and diluted net loss per share	18,134	14,616	17,711	5,292