Unaudited Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Total revenues	$ 16,640	$ 38,673	$ 36,662	$ 70,728
Transaction-based expenses:
Transaction-based expenses	(178)	(1,616)	(311)	(2,592)
Total revenues, less transaction-based expenses	16,462	37,057	36,351	68,136
Operating expenses:
Compensation and benefits	27,384	27,361	71,024	47,857
Professional services	3,853	4,104	7,370	6,804
Acquisition-related transaction costs	692	92	4,398	92
Advertising and market development	1,441	858	2,945	1,845
Rent and occupancy	1,140	910	2,706	1,797
Technology and communications	2,809	2,146	4,832	3,580
General and administrative	3,170	1,035	4,772	1,988
Depreciation and amortization	2,021	1,356	3,103	2,752
Total operating expenses	42,510	37,862	101,150	66,715
Operating (loss) income	(26,048)	(805)	(64,799)	1,421
Interest expenses and other income (expenses):
Interest income (expenses), net	266	(1,780)	287	(2,334)
Change in fair value of warrant liabilities	20,558	(5,404)	(5,402)	(6,312)
Other income (loss), net	140	(10)	529	156
Total interest income (expenses) and other income (expenses)	20,964	(7,194)	(4,586)	(8,490)
Loss before provision for income taxes	(5,084)	(7,999)	(69,385)	(7,069)
Provision for (benefit from) income taxes	35	4	158	(4)
Net loss and comprehensive loss	(5,119)	(8,003)	(69,543)	(7,065)
Net loss and comprehensive loss	$ (5,119)	$ (8,003)	$ (69,543)	$ (7,065)
Net loss per share attributable to common stockholders:
Basic (in dollars per share)	$ (0.03)	$ (0.15)	$ (0.60)	$ (0.12)
Diluted (in dollars per share)	$ (0.20)	$ (0.15)	$ (0.66)	$ (0.12)
Weighted-average shares used in computing net loss per share attributable to common stockholders:
Basic (in shares)	167,052,900	52,504,601	116,815,363	57,038,093
Diluted (in shares)	173,578,093	52,504,601	120,584,585	57,038,093
Placement fees
Revenues:
Total revenues	$ 10,951	$ 32,945	$ 25,536	$ 60,454
Custodial administration fees
Revenues:
Total revenues	$ 5,689	$ 5,728	$ 11,126	$ 10,274