3.	BALANCE SHEET COMPONENTS

Prepaid Expenses and Other Current Assets

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

	December 31,
	2015		2014
Prepaid expenses	$	2,799	$	2,020
Other		283		542
Prepaid expenses and other current assets	$	3,082	$	2,562

Property and Equipment, net

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

	December 31,			December 31,
	2015			2014
Computer equipment	$	13,195		$	11,590
Leasehold improvements		9,882			6,121
Capitalized software costs		1,888			1,754
Office equipment		2,336			1,402
Software licenses		1,768			963
Building, leased		16,438			15,583
Property and equipment – gross		45,507			37,413
Less: accumulated depreciation and amortization		(13,753	)		(8,845	)
Property and equipment – net	$	31,754		$	28,568

Depreciation and amortization expense, excluding amortization of capitalized software and intangible assets, for the years ended December 31, 2015, 2014, and 2013 was $5,862,000, $3,444,000, and $2,371,000, respectively.

The Company capitalized software development costs of $135,000, $185,000, and $907,000 for the years ended December 31, 2015, 2014 and 2013, respectively. Amortization of capitalized software development costs totaled $317,000, $791,000, and $835,000 during the years ended December 31, 2015, 2014 and 2013, respectively. During the year ended December 31, 2014, the Company wrote off $160,000 of cost incurred to integrate acquired technology. The net book value of capitalized software development costs was $351,000 and $535,000 as of December 31, 2015 and 2014, respectively.

During the year ended December 31, 2013, the Company executed a lease for a new 64,000 square foot office building in San Luis Obispo, California. This facility provides additional capacity to accommodate continued growth, and became operational in the second quarter of 2015. Both the landlord and the Company incurred costs to construct the facility according to the Company’s operating specifications, and as a result, the Company has concluded that it is the “deemed owner” of the building (for accounting purposes only) during the construction period. During the year ended December 31, 2015, 2014 and 2013, the landlord incurred building construction costs of $855,000, $11,924,000, and $3,659,000, respectively, which the Company has recorded as an asset, with a corresponding construction financing obligation. During April 2015, the Company began to occupy the facility. Upon completion of the construction, the Company was also the “deemed owner” of the building for accounting purposes as the asset did not qualify for sale-leaseback accounting treatment due to the Company’s continuing involvement. As such, costs included in construction-in-progress for the building was recorded to “Building, Leased” within “Property and equipment, net” and the related financing obligation of $16,236,000 remained recorded as of December 31, 2015. The obligation is being settled through monthly lease payments to the landlord upon completion of the construction, and the asset is being depreciated over the initial term of the lease. The lease has an original term of 15 years and the Company also has an option to extend the term of the lease for three consecutive terms of five years each. The Company is responsible to pay landlord’s insurance costs, real property taxes, and operating expenses related to the premises as additional rent. The Company is also responsible for all tenant improvements and, at inception, was required to deposit $2,533,000 into a restricted account to pay for these improvements. As of December 31, 2015 and 2014, the remaining balance in the deposit account was zero and $772,000, respectively.

Accrued Expenses and Other Liabilities

Accrued expenses and other liabilities consisted of the following (in thousands):

	December 31,
	2015		2014
Accrued payroll	$	3,918	$	3,353
Accrued vacation		1,699		1,323
Employee stock purchase plan contributions		1,496		—
Other liabilities		798		543
Total accrued expenses and other liabilities	$	7,911	$	5,219