(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, 2017	$	266
Charged to expense		76
Write-offs		(85)
Balance at December 31, 2017	$	257

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


	June 30,		December 31,
	2017		2017
Capitalized internal-use software	$	49,663	$	57,758
Accumulated amortization		(32,269)		(38,972)
Capitalized internal-use software, net	$	17,394	$	18,786

Amortization of capitalized internal-use software costs is included in Cost of Revenues-Recurring Revenues and amounted to $1,950 and $3,314 for the three months ended December 31, 2016 and 2017, respectively, and $3,634 and $6,703 for the six months ended December 31, 2016 and 2017, respectively.

Property and equipment, net consist of the following:


	June 30,		December 31,
	2017		2017
Office equipment	$	3,591	$	3,797
Computer equipment		24,411		27,567
Furniture and fixtures		7,547		8,821
Software		4,954		5,008
Leasehold improvements		21,426		29,324
Time clocks rented by clients		4,240		4,489
Total		66,169		79,006
Accumulated depreciation		(25,413)		(30,652)
Property and equipment, net	$	40,756	$	48,354

Depreciation expense amounted to $2,504 and $3,092 for the three months ended December 31, 2016 and 2017, respectively, and $4,707 and $6,017 for the six months ended December 31, 2016 and 2017, respectively.

Intangible assets, net consist of the following:



					Weighted
					Average
	June 30,		December 31,		Useful
	2017		2017		Life
Client relationships	$	12,580	$	12,580	9 years
Non-solicitation agreements		360		360	2 - 3 years
Total		12,940		12,940
Accumulated amortization		(4,033)		(4,751)
Intangible assets, net	$	8,907	$	8,189

Amortization expense for acquired intangible assets was $381 and $359 for the three months ended December 31, 2016 and 2017, respectively, and $762 and $718 for the six months ended December 31, 2016 and 2017, respectively.

Future amortization expense for acquired intangible assets is as follows, as of December 31, 2017:


Remainder of fiscal 2018	$	709
Fiscal 2019		1,398
Fiscal 2020		1,398
Fiscal 2021		1,398
Fiscal 2022		1,398
Thereafter		1,888
Total	$	8,189

The components of accrued expenses were as follows:


	June 30,		December 31,
	2017		2017
Accrued payroll and personnel costs	$	25,131	$	22,405
Other		5,170		6,723
Total accrued expenses	$	30,301	$	29,128