Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Property and Equipment

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

	December 31,
	2017			2016
Prototype	$	11,929		$	6,405
Machine and equipment		7,831			6,057
Leasehold improvements		4,438			4,371
Furniture and fixtures		558			368
Software		1,142			1,028
Construction in progress		-			5,498
Property and equipment, gross		25,898			23,727
Less: accumulated depreciation and amortization		(14,334	)		(12,167	)
Property and equipment, net	$	11,564		$	11,560

Summary of Intangible Assets

Intangible assets consisted of the following (in thousands):

	December 31,
	2017			2016
License cost	$	512		$	512
Patents		104			104
Intangible assets, gross		616			616
Accumulated amortization		(538	)		(519	)
Intangible assets, net	$	78		$	97

Summary of Estimated Future Amortization Expense

At December 31, 2017, the estimated future amortization expense of purchased intangible assets was as follows (in thousands):

Year Ended December 31,	EstimatedFuture Amortization Expense
2018	$	19
2019		19
2020		19
2021		10
2022		3
Thereafter		8
Total amortization expense	$	78

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	December 31,
	2017		2016
Accrued payroll and related benefits	$	3,944	$	4,274
Accrued accounts payable		2,671		1,202
Tax payable		149		13
Accrued legal and accounting		322		509
Other		121		336
Total accrued liabilities	$	7,207	$	6,334

Schedule of Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	December 31,
	2017			2016
Deferred revenue:
Product	$	18,861		$	5,050
Services		1,182			1,561
Distribution rights		3,346			3,822
Total deferred revenue		23,389			10,433
Less: current portion of deferred revenue		(20,151	)		(6,515	)
Noncurrent portion of deferred    revenue	$	3,238		$	3,918