Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue:
Revenue from fees, net		$ 560,431	$ 907,272	$ 801,275
Interest income, interest expense, and fair value adjustments, net:
Interest income	[1]	168,996	105,580	20,634
Interest expense	[1]	(34,894)	(10,843)	(3,274)
Fair value and other adjustments	[1]	(180,971)	(159,565)	29,954
Total interest income, interest expense, and fair value adjustments, net		(46,869)	(64,828)	47,314
Revenue from fees, net		513,562	842,444	848,589
Operating expenses:
Sales and marketing		127,143	345,776	333,453
Customer operations		150,418	187,994	117,579
Engineering and product development		280,138	237,247	133,999
General, administrative, and other		212,388	185,290	122,677
Total operating expenses		770,087	956,307	707,708
Income (loss) from operations		(256,525)	(113,863)	140,881
Other income (expense), net		21,206	9,473	(5,174)
Expense on convertible notes		(4,706)	(4,684)	(1,976)
Net income (loss) before income taxes		(240,025)	(109,074)	133,731
(Benefit) provision for income taxes		107	(409)	(1,712)
Net income (loss)		$ (240,132)	$ (108,665)	$ 135,443
Net income (loss) per share, basic (in dollars per share)		$ (2.87)	$ (1.31)	$ 1.73
Net income (loss) per share, diluted (in dollars per share)		$ (2.87)	$ (1.31)	$ 1.43
Weighted-average number of shares outstanding used in computing net income (loss) per share, basic (in shares)		83,765,896	82,771,268	78,106,359
Weighted-average number of shares outstanding used in computing net income (loss) per share, diluted (in shares)		83,765,896	82,771,268	94,772,641

[1] Balances for year ended December 31, 2023 include amounts related to the consolidated securitization. Refer to “Note 2. Revenue” for details.