Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Schedule of Property and Equipment

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

	March 31, 2018			December 31, 2017
Prototype	$	11,938		$	11,929
Machinery and equipment		9,731			7,831
Leasehold improvements		4,565			4,438
Software		1,120			1,142
Furniture and fixtures		588			558
Property and equipment, gross		27,942			25,898
Less: accumulated depreciation and amortization		(14,987	)		(14,334	)
Property and equipment, net	$	12,955		$	11,564

Summary of Intangible Assets

Intangible assets consisted of the following (in thousands):

	March 31, 2018			December 31, 2017
License cost	$	512		$	512
Patents		104			104
Intangible assets, gross		616			616
Accumulated amortization		(543	)		(538	)
Intangible assets, net	$	73		$	78

Summary of Estimated Future Amortization Expense

At March 31, 2018, the estimated future amortization expense of intangible assets was as follows (in thousands):

Year Ending December 31,	EstimatedFuture Amortization Expense
The remainder of 2018	$	14
2019		19
2020		19
2021		10
2022		3
2023		1
Thereafter		7
Total amortization expense	$	73

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2018		December 31, 2017
Accrued payroll and related benefits	$	5,062	$	3,944
Accrued accounts payable		2,180		2,671
Accrued legal, accounting and governance fees		198		322
Tax payable		401		149
Other		56		121
Total accrued liabilities	$	7,897	$	7,207

Schedule of Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	March 31, 2018			December 31, 2017
Deferred revenue:
Product	$	6,551		$	18,861
Services		3,234			1,182
Distribution rights		3,228			3,346
Total deferred revenue		13,013			23,389
Less: current portion of deferred revenue		(9,670	)		(20,151	)
Noncurrent portion of deferred revenue	$	3,343		$	3,238