5.	Balance Sheet Components

Property and Equipment

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

	September 30, 2015			December 31, 2014
	(Unaudited)
Prototype	$	6,471		$	6,342
Machine and equipment		5,605			4,214
Leasehold improvements		1,274			1,270
Furniture and fixtures		347			263
Software		790			647
Construction in progress		1,402			—
Property and equipment, gross		15,889			12,736
Less: accumulated depreciation and amortization		(10,593	)		(9,805	)
Property and equipment, net	$	5,296		$	2,931

Depreciation and amortization expense related to property and equipment was $280 thousand, $207 thousand, $788 thousand and $612 thousand during the three months ended September 30, 2015 and 2014 and the nine months ended September 30, 2015 and 2014, respectively.

Intangible Assets

Intangible assets consisted of the following (in thousands):

	September 30, 2015			December 31, 2014
	(Unaudited)
Intangible assets – license cost	$	500		$	500
Accumulated amortization		(361	)		(236	)
Intangible assets, net	$	139		$	264

Intangible amortization expense was $42 thousand, $42 thousand, $125 thousand and $125 thousand during the three months ended September 30, 2015 and 2014 and the nine months ended September 30, 2015 and 2014, respectively, which were recorded in general and administrative expenses in the condensed consolidated statements of operations.

At September 30, 2015, 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 2015	$	42
2016		97
Total amortization expense	$	139

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	September 30, 2015		December 31, 2014
	(Unaudited)
Accrued payroll and related benefits	$	1,779	$	1,652
Accrued accounts payable		478		946
Sales tax and medical device excise tax payable		33		499
Accrued legal and accounting		410		901
Accrued interest		—		142
Accrued debt facility fee		1,500		—
Other		814		296
Total accrued liabilities	$	5,014	$	4,436

Deferred Revenue

Deferred revenue consisted of the following (in thousands):

	September 30, 2015			December 31, 2014
	(Unaudited)
Deferred revenue:
Product	$	5,050		$	6,919
Services		573			442
Total deferred revenue		5,623			7,361
Less: current portion of deferred revenue		(5,249	)		(7,361	)
Noncurrent portion of deferred revenue	$	374		$	—