Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 133,667	$ 45,718	[1]
Accounts receivable	9,298	3,414
Prepaid expenses	13,561	7,658
Inventory	1,158	797
Income tax receivable	4,020	3,962
Deferred contract costs	46,618	35,286
Current assets before funds held for clients	208,322	96,835
Funds held for clients	1,662,778	967,787
Total current assets	1,871,100	1,064,622
Property and equipment, net	238,458	176,962
Goodwill	51,889	51,889
Long-term deferred contract costs	292,134	225,459
Other assets	33,336	2,994
Total assets	2,486,917	1,521,926
Current liabilities:
Accounts payable	5,051	6,288
Accrued commissions and bonuses	12,343	10,671
Accrued payroll and vacation	14,870	10,741
Deferred revenue	11,105	8,980
Current portion of long-term debt	1,775	1,775
Accrued expenses and other current liabilities	45,600	22,440
Current liabilities before client funds obligation	90,744	60,895
Client funds obligation	1,662,778	967,787
Total current liabilities	1,753,522	1,028,682
Deferred income tax liabilities, net	91,217	70,206
Long-term deferred revenue	65,139	55,671
Net long-term debt, less current portion	30,858	32,614
Other long-term liabilities	19,553
Total long-term liabilities	206,767	158,491
Total liabilities	1,960,289	1,187,173
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.01 par value (100,000 shares authorized, 61,350 and 60,747 shares issued at December 31, 2019 and 2018, respectively; 57,660 and 57,277 shares outstanding at December 31, 2019 and 2018, respectively)	613	607
Additional paid in capital	257,501	203,680
Retained earnings	576,166	395,590
Treasury stock, at cost (3,689 and 3,470 shares at December 31, 2019 and 2018, respectively)	(307,652)	(265,124)
Total stockholders' equity	526,628	334,753
Total liabilities and stockholders' equity	$ 2,486,917	$ 1,521,926

[1] Amounts have been adjusted to reflect the adoption of Accounting Standards Update No. 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force).” See Note 2 for a summary of reclassifications and adjustments.