(3) Balance Sheet Information

The following tables provide details of selected consolidated balance sheet items:

Activity in the allowance for doubtful accounts was as follows:


Balance at June 30, 2016	$	193
Charged to expense		60
Write-offs		(9)
Balance at December 31, 2016	$	244

Capitalized internal-use software and accumulated amortization were as follows:


	June 30,		December 31,
	2016		2016
Capitalized internal-use software	$	34,249	$	41,400
Accumulated amortization		(22,822)		(26,456)
Capitalized internal-use software, net	$	11,427	$	14,944

Amortization of capitalized internal-use software costs is included in Cost of Revenues-Recurring Revenues and amounted to $1,423 and $1,950 for the three months ended December 31, 2015 and 2016, respectively, and $2,365 and $3,634 for the six months ended December 31, 2015 and 2016, respectively.

Property and equipment, net consist of the following:


	June 30,		December 31,
	2016		2016
Office equipment	$	2,528	$	3,538
Computer equipment		18,139		22,882
Furniture and fixtures		4,308		5,490
Software		5,059		5,581
Leasehold improvements		11,164		13,895
Time clocks rented by clients		4,046		4,349
		45,244		55,735
Accumulated depreciation		(18,457)		(22,102)
Property and equipment, net	$	26,787	$	33,633

Depreciation expense amounted to $1,632 and $2,504 for the three months ended December 31, 2015 and 2016, respectively, and $3,029 and $4,707 for the six months ended December 31, 2015 and 2016, respectively.

Intangible assets, net consist of the following:


					Weighted
					Average
	June 30,		December 31,		Useful
	2016		2016		Life
Client relationships	$	12,580	$	12,580	9 years
Non-solicitation agreements		360		360	2 - 3 years
Total		12,940		12,940
Accumulated amortization		(2,521)		(3,283)
Intangible assets, net	$	10,419	$	9,657

Amortization expense for acquired intangible assets was $381 for both of the three months ended December 31, 2015 and 2016 and $761 and $762 for the six months ended December 31, 2015 and 2016, respectively.

Future amortization expense for acquired intangible assets is as follows, as of December 31, 2016:


Remainder of fiscal 2017	$	750
Fiscal 2018		1,427
Fiscal 2019		1,398
Fiscal 2020		1,398
Fiscal 2021		1,398
Thereafter		3,286
Total	$	9,657

The components of accrued expenses were as follows:


	June 30,		December 31,
	2016		2016
Accrued payroll and personnel costs	$	21,658	$	18,795
Current portion of deferred rent		504		243
Other		2,817		3,058
Total accrued expenses	$	24,979	$	22,096