4. Balance Sheet Components

Allowance for Doubtful Accounts

Activity related to the allowance for doubtful accounts consisted of the following (in thousands):

	Nine Months Ended September 30, 2015			Year Ended December 31, 2014
Balance, beginning of period	$	13		$	20
Additions to the allowance		29			129
Write-offs of bad debt		(12	)		(119	)
Recovery of previously reserved items		(7	)		(17	)
Balance, end of period	$	23		$	13

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):

	September 30, 2015		December 31, 2014
Prepaid expenses	$	3,483	$	1,846
Refundable tax		439		492
Deferred commissions		1,209		871
Gain on unsettled foreign currency forward contracts		–		5
Other current assets		1,746		1,211
Prepaid expenses and other current assets	$	6,877	$	4,425

Property and Equipment, Net

Property and equipment, net consist of the following (in thousands):

	September 30, 2015			December 31, 2014
Computer equipment	$	30,560		$	26,406
Furniture, fixtures, and equipment		696			716
Leasehold improvements		2,986			2,447
Total property and equipment(1)		34,242			29,569
Less accumulated depreciation and amortization(2)		(23,462	)		(20,088	)
Property and equipment, net	$	10,780		$	9,481

(1)	Includes assets under capital lease of $5.4 million as of September 30, 2015 and December 31, 2014, respectively.
(2)	Includes accumulated amortization of $3.7 million and $2.8 million relating to assets under capital lease as of September 30, 2015 and December 31, 2014, respectively.

Depreciation expense was $1.4 million and $1.1 million for the three months ended September 30, 2015 and 2014, respectively, and $3.6 million and $2.6 million for the nine months ended September 30, 2015 and 2014, respectively. Included in these amounts were depreciation expenses for assets acquired under capital leases in the amount of $0.3 million and $0.9 million for the three and nine months ended September 30, 2015, respectively, and $0.3 million and $0.6 million for the three and nine months ended September 30, 2014, respectively.

Other Assets

Other assets consist of the following (in thousands):

	September 30, 2015		December 31, 2014
Deferred costs and commissions		895		674
Facility deposits for operating leases		891		891
Others		83		44
Other assets	$	1,869	$	1,609

Accumulated Other Comprehensive Loss

The components of accumulated other comprehensive loss, net of tax, are as follows (in thousands):

	September 30, 2015		December 31, 2014
Foreign currency translation adjustments	$	1,901	$	1,626
Net unrealized loss on foreign currency contracts designated as cash flow hedges		517		353
Total accumulated other comprehensive loss	$	2,418	$	1,979