Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (61,200)	$ (17,027)	$ (22,803)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization	5,516	5,624	5,881
Provision for bad debts	204	61	114
Loss on extinguishment of debt and amortization of debt discount	2,799	278	94
Reduction in carrying amount of operating right-of-use assets	2,628	0	0
Stock-based compensation expense	26,151	3,063	2,114
Change in fair value of financial instruments and other income	9,996	520	12
Deferred income taxes	(137)	196	192
Changes in assets and liabilities:
Accounts receivable	(10,420)	(3,413)	(4,783)
Prepaid expenses	(755)	407	(1,321)
Deferred implementation, commissions, and other costs	(903)	(756)	(1,464)
Other assets (current and non-current)	1,399	(4,028)	(333)
Accounts payable	786	(1,656)	1,765
Accrued expenses and other	12,315	11,962	6,868
Lease liabilities	(2,920)	0	0
Deferred revenue	5,805	4,688	6,005
Other liabilities (current and non-current)	(824)	(136)	384
Net cash used in operating activities	(9,560)	(217)	(7,275)
Cash flows from investing activities:
Purchase of businesses	(56,833)	0	(6,335)
Purchases of marketable securities	(45,117)	0	0
Purchases of property and equipment	(1,633)	(1,756)	(4,317)
Net cash used in investing activities	(103,583)	(1,756)	(10,652)
Cash flows from financing activities:
Proceeds from borrowings, net of costs	0	49,554	24,750
Payments on borrowings	(44,663)	(34,921)	(6,333)
Business Combination and PIPE financing	349,638	0	0
Payments of equity issuance costs	(19,936)	0	0
Debt extinguishment costs	(1,565)	0	0
Change in customer funds payable	1,617	(202)	3,505
Payments on finance leases	(228)
Payments on finance leases		(261)	(276)
Proceeds from common stock issued	6,742	1,308	1,127
Taxes paid on net share issuance of stock-based compensation	(4,490)	(524)	0
Deferred acquisition payments	0	0	0
Net cash provided by financing activities	287,115	14,954	22,773
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(6)	0	0
Net increase in cash, cash equivalents, and restricted cash	173,966	12,981	4,846
Cash, cash equivalents, and restricted cash, beginning of period	38,843	25,862	21,016
Cash, cash equivalents, and restricted cash, end of period	212,809	38,843	25,862
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest	135	4,238	1,266
Cash paid for/(received from) income taxes	0	(41)	3
Noncash Investing & Financing Activities:
Fixed assets purchased under finance leases	31	6	210
Contingent consideration (Note 3)	5,085	0	1,066
Deferred purchase price (Note 3)	579	0	1,131
Equity issuance costs charged to additional paid-in-capital	1,624	0	0
Net assets acquired in Business Combination and other	255	0	0
Reclassification of stock warrant liability to equity (Note 3)	1,433	0	0
Issuance and vesting of Earnout Shares (Note 3)	$ 237,008	$ 0	$ 0