Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2015

Balance Sheet Related Disclosures [Abstract]

Schedule of Property and Equipment

Property and equipment consisted of the following (in thousands):

	December 31
	2015			2014
Prototype	$	6,492		$	6,342
Machine and equipment		7,128			4,214
Leasehold improvements		1,532			1,270
Furniture and fixtures		350			263
Software		832			647
Construction in progress		1,851			—
Property and equipment, gross		18,185			12,736
Less: accumulated depreciation and amortization		(10,879	)		(9,805	)
Property and equipment, net	$	7,306		$	2,931

Summary of Intangible Assets

Intangible assets consisted of the following (in thousands):

	December 31
	2015			2014
License cost	$	500		$	500
Patents		104			—
Intangible assets, gross	$	604		$	500
Accumulated amortization		(404	)		(236	)
Intangible assets, net	$	200		$	264

Summary of Estimated Future Amortization Expense

At December 31, 2015, the estimated future amortization expense of purchased intangible assets was as follows (in thousands):

Year Ended December 31,	EstimatedFuture Amortization Expense
2016	$	115
2017		18
2018		18
2019		18
2020		18
Thereafter		13
Total amortization expense	$	200

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	December 31
	2015		2014
Accrued payroll and related benefits	$	1,938	$	1,652
Accrued accounts payable		1,880		143
Sales tax and medical device excise tax payable		219		499
Accrued legal and accounting		857		901
Accrued interest		—		142
Other		519		296
Total accrued liabilities	$	5,413	$	3,633

Schedule of Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	December 31
	2015			2014
Deferred revenue:
Product	$	5,050		$	6,919
Services		911			442
Total deferred revenue		5,961			7,361
Less: current portion of deferred revenue		(5,616	)		(7,361	)
Noncurrent portion of deferred revenue	$	345		$	—