Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net loss	$ (32,562)	$ (73,023)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	10,581	6,366
Stock-based compensation	25,764	19,792
Amortization of debt discount and issuance costs	5,254	4,674
Non-cash lease expense	6,821	4,727
Impairment costs	2,063	0
Other	(693)	(401)
Change in assets and liabilities:
Accounts receivable, net	(21,862)	(9,071)
Inventory	49,597	(82,766)
Prepaid expenses and other assets	5,168	(82)
Accounts payable	851	579
Accrued liabilities, other payables, and non-current payroll tax liabilities	28,469	18,994
Lease liabilities	(8,368)	(5,095)
Origination of loans held for sale	(479,153)	(285,182)
Proceeds from sale of loans originated as held for sale	459,605	267,850
Net cash provided by (used in) operating activities	51,535	(132,638)
Investing activities
Purchases of property and equipment	(10,391)	(12,821)
Purchases of investments	(135,118)	(106,063)
Sales of investments	6,583	1,005
Maturities of investments	82,772	4,900
Net cash used in investing activities	(56,154)	(112,979)
Financing activities
Proceeds from the issuance of convertible preferred stock, net of issuance costs	39,801	0
Proceeds from the issuance of common stock, net of issuance costs	69,701	0
Proceeds from the issuance of shares resulting from employee equity plans	15,119	10,869
Tax payments related to net share settlements on restricted stock units	(10,987)	(2,856)
Borrowings from warehouse credit facilities	473,283	280,129
Repayments to warehouse credit facilities	(454,277)	(262,875)
Borrowings from secured revolving credit facility	57,378	0
Repayments to secured revolving credit facility	(46,899)	0
Other payables—deposits held in escrow	2,097	637
Principal payments for finance lease obligations	(59)	0
Cash paid for debt issuance costs	(4)	(152)
Net cash provided by financing activities	145,153	25,752
Effect of exchange rate changes on cash and cash equivalents	(16)	28
Net change in cash, cash equivalents, and restricted cash	140,518	(219,837)
Cash, cash equivalents, and restricted cash:
Beginning of period	247,448	439,055
End of period	387,966	219,218
Supplemental disclosure of cash flow information
Cash paid for interest	3,001	2,460
Non-cash transactions
Stock-based compensation capitalized in property and equipment	1,714	931
Property and equipment additions in accounts payable and accrued liabilities	973	404
Leasehold improvements paid directly by lessor	$ 37	$ 4,298