Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net income	$ 149,285	$ 116,894
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	44,223	30,933
Accretion of discount on available-for-sale securities	(637)	(183)
Non-cash marketing expense	876	157
Loss on disposition of property and equipment		132
Amortization of debt issuance costs	167	18
Stock-based compensation expense	46,323	47,373
Cash paid for derivative settlement	(300)	(418)
Gain on derivative	(1,368)	(287)
Deferred income taxes, net	(9,646)	6,485
Changes in operating assets and liabilities:
Accounts receivable	(10,588)	(10,775)
Prepaid expenses	(14,050)	(14,430)
Inventory	(1,166)	80
Other assets	(5,308)	1,631
Deferred contract costs	(57,746)	(44,893)
Accounts payable	7,655	2,267
Income taxes, net	16,193	2,450
Accrued commissions and bonuses	(7,559)	(3,785)
Accrued payroll and vacation	7,543	4,111
Deferred revenue	7,454	5,632
Accrued expenses and other current liabilities	(2,393)	3,051
Net cash provided by operating activities	168,958	146,443
Cash flows from investing activities
Purchases of investments from funds held for clients	(233,789)	(142,051)
Proceeds from investments from funds held for clients	279,000	155,000
Purchases of property and equipment	(67,721)	(62,732)
Net cash used in investing activities	(22,510)	(49,783)
Cash flows from financing activities
Proceeds from issuance of debt	29,000
Repurchases of common stock	(94,652)
Withholding taxes paid related to net share settlements	(4,793)	(32,355)
Payments on long-term debt	(29,287)	(888)
Net change in client funds obligation	1,579,000	411,878
Payment of debt issuance costs	(1,297)
Net cash provided by financing activities	1,477,971	378,635
Increase in cash, cash equivalents, restricted cash and restricted cash equivalents	1,624,419	475,295
Cash, cash equivalents, restricted cash and restricted cash equivalents
Cash, cash equivalents, restricted cash and restricted cash equivalents, beginning of period	1,812,691	1,585,275
Cash, cash equivalents, restricted cash and restricted cash equivalents, end of period	3,437,110	2,060,570
Cash and cash equivalents	279,039	202,362
Restricted cash included in funds held for clients	3,158,071	1,858,208
Non-cash investing and financing activities:
Purchases of property and equipment, accrued but not paid	3,831	7,131
Stock-based compensation for capitalized software	4,180	3,351
Right of use assets obtained in exchange for operating lease liabilities	$ 7,940	$ 1,572