3.	Balance Sheet Components

Property and Equipment

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

	September 30, 2016			December 31, 2015
	(Unaudited)
Prototype	$	6,405		$	6,492
Machinery and equipment		6,148			7,128
Leasehold improvements		4,621			1,532
Furniture and fixtures		363			350
Software		960			832
Construction in progress		5,331			1,851
Property and equipment, gross		23,828			18,185
Less: accumulated depreciation and amortization		(11,920	)		(10,879	)
Property and equipment, net	$	11,908		$	7,306

Depreciation and amortization expense related to property and equipment were $451 thousand, $280 thousand during the three months ended September 30, 2016 and 2015, and $1.2 million and $788 thousand during the nine months ended September 30, 2016 and 2015, respectively.

Intangible Assets

Intangible assets consisted of the following (in thousands):

	September 30, 2016			December 31, 2015
	(Unaudited)
License cost	$	512		$	500
Patents		104			104
Intangible assets, gross	$	616		$	604
Accumulated amortization		(514	)		(404	)
Intangible assets, net	$	102		$	200

Intangible amortization expense were $18 thousand, $42 thousand during the three months ended September 30, 2016 and 2015, and $110 thousand and $125 thousand during the nine months ended September 30, 2016 and 2015, respectively. Amortization of intangible assets was recorded in general and administrative expenses in the condensed consolidated statements of operations.

At September 30, 2016, the estimated future amortization expense of purchased intangible assets was as follows (in thousands):

Year Ending December 31,	Estimated Future Amortization Expense
	(Unaudited)
The remainder of 2016	$	5
2017		19
2018		19
2019		19
2020		19
2021		11
Thereafter		10
Total amortization expense	$	102

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	September 30, 2016		December 31, 2015
	(Unaudited)
Accrued payroll and related benefits	$	3,123	$	1,938
Accrued accounts payable		1,199		1,880
Sales tax and medical device excise tax payable		96		219
Accrued legal, accounting and governance fees		783		857
Other		417		519
Total accrued liabilities	$	5,618	$	5,413

Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	September 30, 2016			December 31, 2015
	(Unaudited)
Deferred revenue:
Product	$	10,900		$	5,050
Services		821			911
Distribution rights (see Note 7)		3,941			—
Total deferred revenue		15,662			5,961
Less: current portion of deferred revenue		(12,006	)		(5,616	)
Noncurrent portion of deferred revenue	$	3,656		$	345