Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Revenue:
Device and related	$ 7,315	$ 13,434		$ 4,352
Engineering services	38	787		4,309
Total revenue	7,353	14,221		8,661
Cost of revenue:
Device and related	5,270	10,715		3,926
Engineering services	14	559		3,556
Total cost of revenue	5,284	11,274		7,482
Gross profit	2,069	2,947		1,179
Operating expenses:
Sales and marketing	13,156	10,997		9,258
Research and development	9,483	8,879		6,480
General and administrative	10,715	10,853		7,002
Restructuring	659	0		0
Change in fair value, contingent consideration	(332)	(196)		0
Total operating expenses	33,681	30,533		22,740
Loss from operations	(31,612)	(27,586)		(21,561)
Other income, net:
Interest expense	(648)	(16)		(13)
Warrant issuance expense	0	0		(487)
Gain on warrant liability	3,909	4,286		2,505
Loss on repurchase of warrants	(1,067)	0		0
Interest income	0	12		11
Other expense, net	296	(166)		(45)
Total other income, net	2,490	4,116		1,971
Net loss	(29,122)	(23,470)		(19,590)
Less: Preferred deemed dividend	0	10,345		4,655
Net loss applicable to common shareholders	(29,122)	(33,815)	[1]	(24,245)
Foreign currency translation adjustments	(419)	80		(1)
Comprehensive loss applicable to common shareholders	$ (29,541)	$ (33,735)		$ (24,246)
Basic net loss per share applicable to common shareholders	$ (0.82)	$ (1.87)	[1]	$ (1.66)
Diluted net loss per share applicable to common shareholders	$ (0.82)	$ (2.05)	[1]	$ (1.83)
Weighted average number of shares outstanding, basic (in shares)	35,609	18,126	[1]	14,606
Weighted average number of shares outstanding, diluted (in shares)	35,609	18,622	[1]	14,609

[1] Recognition of previously deferred revenue and cost of goods in the year ended December 31, 2016 reduced net loss applicable to common stockholders by $2,358, or $0.13 per share (see Note 2. Basis of Presentation and Summary of Significant Accounting Policies and Estimates – Medical Device Revenue and Cost of Revenue Recognition).