Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 524,109	$ 400,509
Research and development credits	133,173	88,823
Inventory	68,840	15,115
Share-based compensation	66,345	43,065
Interest expense limitation	58,155	30,921
Lease liability	41,402	57,606
Accruals and reserves	12,782	3,988
Depreciation and amortization	1,496	1,035
Other deferred tax assets	1,100	4,736
Total deferred tax assets	907,402	645,798
Deferred tax liabilities:
Debt discount on convertible senior notes	(60,448)	(80,280)
Website and software development costs	(43,814)	(32,021)
Right of use assets	(32,027)	(45,857)
Intangible assets	(21,697)	(12,968)
Goodwill	(4,631)	(3,267)
Total deferred tax liabilities	(162,617)	(174,393)
Net deferred tax assets before valuation allowance	744,785	471,405
Less: valuation allowance	(745,732)	(471,901)
Net deferred tax liabilities	$ (947)	$ (496)