Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue:
Revenue from fees, net		$ 130,532	$ 143,689	$ 268,600	$ 260,830
Interest income, interest expense, and fair value adjustments, net:
Interest income	[1]	52,883	33,916	104,054	79,231
Interest expense	[1]	(11,470)	(4,282)	(22,184)	(11,414)
Fair value and other adjustments	[1]	(44,315)	(37,557)	(95,046)	(89,954)
Total interest income, interest expense, and fair value adjustments, net		(2,902)	(7,923)	(13,176)	(22,137)
Total revenue		127,630	135,766	255,424	238,693
Operating expenses:
Sales and marketing		32,958	23,891	68,108	55,329
Customer operations		38,684	36,797	78,092	77,387
Engineering and product development		58,453	57,974	121,544	168,045
General, administrative, and other		53,021	50,448	110,634	103,111
Total operating expenses		183,116	169,110	378,378	403,872
Loss from operations		(55,486)	(33,344)	(122,954)	(165,179)
Other income, net		1,031	5,197	3,915	7,794
Net loss before income taxes		(54,455)	(28,147)	(119,039)	(157,385)
Provision for income taxes		15	18	29	34
Net loss		$ (54,470)	$ (28,165)	$ (119,068)	$ (157,419)
Net loss per share, basic (in dollars per share)		$ (0.62)	$ (0.34)	$ (1.36)	$ (1.91)
Net loss per share, diluted (in dollars per share)		$ (0.62)	$ (0.34)	$ (1.36)	$ (1.91)
Weighted-average number of shares outstanding used in computing net loss per share, basic (in shares)		88,435,893	83,130,638	87,733,294	82,524,403
Weighted-average number of shares outstanding used in computing net loss per share, diluted (in shares)		88,435,893	83,130,638	87,733,294	82,524,403

[1] Balances for three and six months ended June 30, 2024 include amounts related to the consolidated securitization. Refer to “Note 2. Revenue” for details.