Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Product	$ 2,759,942	$ 3,532,028
Service	2,372,788	183,758
Other		325,789
Total revenue	5,132,730	4,041,575
Cost of revenue	4,135,884	3,335,511
Gross margin	996,846	706,064
Operating expenses:
Selling, general and administrative	17,427,777	14,994,410
Research and development	7,900,311	4,601,718
Total operating expenses	25,328,088	19,596,128
Operating loss	(24,331,242)	(18,890,064)
Other income (expense):
Loss from change in stock warrant valuation	0	(239,683)
Interest expense	(1,867,466)	(1,719,475)
Interest income	112,413	85,859
Loss on settlement of convertible debt		(705,217)
Other	56,863	80,978
Total other income (expense)	(1,698,190)	(2,497,538)
Net loss before income taxes	(26,029,432)	(21,387,602)
Income taxes	10,118	10,189
Net loss	(26,039,550)	(21,397,791)
Accretion of stock issuance costs	0	(35,046)
Accretion of Series E warrant discount		(127,616)
Accretion of Series D and E redeemable convertible preferred stock dividends		(1,165,932)
Net loss attributable to common stockholders	$ (26,039,550)	$ (22,726,385)
Net loss per share attributable to common stockholders, basic and diluted	$ (3.66)	$ (5.03)
Shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,113,075	4,518,499