Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 54,630	$ 46,077
Accounts receivable	2,414	1,576
Prepaid expenses	8,025	4,982
Inventory	477	979
Income tax receivable	5,602	7,047
Derivative asset	57
Deferred contract costs	30,540	26,403
Current assets before funds held for clients	101,745	87,064
Funds held for clients	900,287	1,089,201
Total current assets	1,002,032	1,176,265
Property and equipment, net	165,370	147,705
Deposits and other assets	1,609	1,456
Goodwill	51,889	51,889
Intangible assets, net	852	958
Long-term derivative asset	435
Long-term deferred contract costs	196,778	171,865
Total assets	1,418,965	1,550,138
Current liabilities:
Accounts payable	4,995	6,490
Accrued commissions and bonuses	4,441	9,585
Accrued payroll and vacation	8,895	7,015
Deferred revenue	7,867	6,982
Current portion of long-term debt	1,775	888
Accrued expenses and other current liabilities	18,796	19,991
Current liabilities before client funds obligation	46,769	50,951
Client funds obligation	900,287	1,089,201
Total current liabilities	947,056	1,140,152
Deferred income tax liabilities, net	59,363	49,129
Long-term derivative liability		554
Long-term deferred revenue	49,322	44,642
Net long-term debt, less current portion	33,486	34,414
Total long-term liabilities	142,171	128,739
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value (100,000,000 shares authorized, 60,638,672 and 60,149,411 shares issued at June 30, 2018 and December 31, 2017, respectively; 57,701,124 and 57,788,573 shares outstanding at June 30, 2018 and December 31, 2017, respectively)	606	601
Additional paid-in capital	193,288	161,809
Retained earnings	335,407	258,525
Treasury stock, at cost (2,937,548 and 2,360,838 shares at June 30, 2018 and December 31, 2017, respectively)	(199,563)	(139,688)
Total stockholders' equity	329,738	281,247
Total liabilities and stockholders' equity	$ 1,418,965	$ 1,550,138