Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue:
Product	$ 5,020	$ 2,435	$ 5,119	$ 5,702
Service	56	159	419	229
Grant	240		240
Total revenue	5,316	2,594	5,778	5,931
Cost of revenue:
Product	5,766	2,753	6,311	7,858
Service	325	158	1,390	413
Total cost of revenue	6,091	2,911	7,701	8,271
Gross margin	(775)	(317)	(1,923)	(2,340)
Operating expenses:
Research and development	2,902	2,291	7,408	7,451
Selling and marketing	1,124	993	3,315	3,572
General and administrative	4,282	3,483	15,779	9,395
Total operating expenses	8,308	6,767	26,502	20,418
Loss from operations	(9,083)	(7,084)	(28,425)	(22,758)
Interest income		1	1	1
Interest expense	(1,053)	(525)	(2,376)	(1,505)
Other income (expense), net	(124)	39	(89)	82
Loss before provision for income taxes	(10,260)	(7,569)	(30,889)	(24,180)
Net loss	(10,260)	(7,569)	(30,889)	(24,180)
Deemed capital contribution on repurchase of Series A preferred stock				9
Net loss attributable to common stockholders	$ (10,260)	$ (7,569)	$ (30,889)	$ (24,171)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.35)	$ (8.41)	$ (2.96)	$ (27.25)
Weighted-average common shares used to compute net loss per share attributable to common stockholders, basic and diluted	29,157,069	900,062	10,433,051	887,189