CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (9,582)	$ (14,542)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Provision for transaction losses	2,078	4,612
Depreciation and amortization	4,498	3,542
Amortization of debt issuance costs	39	64
Amortization of discount on purchases of marketable securities	(948)	0
Change in fair value of redeemable convertible preferred stock warrant liability	0	3,610
Change in fair value of Tides Foundation common stock warrant	439	0
Stock-based compensation expense	10,858	5,667
Loss on disposal of fixed assets	0	33
Changes in operating assets and liabilities:
Trade and client receivables	(11,885)	(15,137)
Prepaid expenses and other assets	(1,439)	(658)
Accounts payable	697	5,006
Accrued expenses and other liabilities	5,814	(490)
Deferred revenue	1,432	103
Net cash provided by (used in) operating activities	2,001	(8,190)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(131,950)	0
Sale of marketable securities	72,500	0
Increase in restricted cash	0	(94)
Purchases of property and equipment	(10,230)	(1,598)
Internal-use software and platform development costs	(4,054)	(2,670)
Net cash used in investing activities	(73,734)	(4,362)
CASH FLOWS FROM FINANCING ACTIVITIES:
Changes in funds held in escrow, including funds in transit	(16,407)	(20,283)
Changes in escrow funds payable	16,407	20,283
Proceeds from exercises of stock options and common stock warrants	13,974	7,011
Proceeds from borrowings on debt	50,000	15,000
Repayment of debt	(53,786)	0
Proceeds from employee stock purchase plan	3,577	0
Payments of costs related to the initial public offering	0	(3,999)
Net cash provided by financing activities	13,765	18,012
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(57,968)	5,460
Cash and cash equivalents, beginning of period	129,128	21,595
Cash and cash equivalents, end of period	71,160	27,055
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for income taxes	31	7
Cash paid for interest	1,027	1,573
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment purchased but not yet paid	905	166
Unpaid deferred offering costs	$ 0	$ 1,583