5. Balance Sheet Components

Allowance for Doubtful Accounts

The following table presents a reconciliation of the allowance for doubtful accounts:


	December 31,		December 31,
	2015		2014
	(in thousands)
Beginning balance	$	527	$	508
Provision for estimated bad debts		529		349
Write offs		(85)		(330)
Ending balance	$	971	$	527

Property and Equipment, net

The Company’s property and equipment consisted of the following:


		December 31,		December 31,
	Useful Life	2015		2014
		(in thousands)
Machinery and equipment	3-5 years	$	20,670	$	18,632
Furniture and fixtures	3 years		217		217
Computer equipment	3 years		911		700
Capitalized software held for internal use	3 years		1,037		—
Leasehold improvements	Life of lease		1,686		1,036
Construction-in-process			1,979		3,583
			26,500		24,168
Less: Accumulated depreciation and amortization			(13,790)		(9,594)
Total Property and Equipment, net		$	12,710	$	14,574

All of the Company’s long-lived assets are located in the United States.

In September 2015, the Company paid off the Equipment Financing Facility, thus none of the Company's equipment is subject to pledge.

The Company periodically evaluates the carrying value of long-lived assets when events or circumstances warrant such a review. The carrying value of a long-lived asset is considered impaired when the estimated realizable value of the asset is less than the carrying value of the asset. In that event, a loss is recognized based on the amount by which the carrying value exceeds the fair value of the long-lived asset. Fair value is determined based on the estimated realizable value of the long-lived asset.

The Company recorded an asset impairment charge of $1.0 million against a specific group of machinery and equipment during the year ended December 31, 2015. The Company no longer uses this specific group of machinery and equipment because of outsourcing to its partners. The impairment charge was recorded to reflect reductions in the estimated realizable value of the machinery and equipment as a result of planning for its sale in the secondary market. The Company recorded the total impairment charge of $1.0 million in cost of product revenue. The Company sold some of the impaired machinery and equipment during the fourth quarter of 2015 for $0.5 million and classified the remaining impaired machinery and equipment as held for sale at the estimated realizable value of $0.2 million. The remaining impaired machinery was sold in January 2016 for $0.2 million.

Accrued Compensation

The Company’s accrued compensation consisted of the following:


	December 31,		December 31,
	2015		2014
	(in thousands)
Accrued paid time off	$	2,024	$	1,577
Accrued commissions		3,691		2,651
Accrued bonuses		1,348		1,141
Other accrued compensation		1,489		611
Total accrued compensation	$	8,552	$	5,980

Other Accrued Liabilities

The Company’s other accrued liabilities consisted of the following:


	December 31,		December 31,
	2015		2014
	(in thousands)
Accrued expenses	$	17,870	$	8,560
Accrued rent		450		551
Deferred lease obligation		42		99
Accrued interest		—		764
Sales tax payable		346		367
Total other accrued liabilities	$	18,708	$	10,341