Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 07, 2021
Summary Of Significant Accounting Policies [Line Items]
Provision for depreciation	$ 3,835,000	$ 1,701,000
Inventories serving as collateral for short-term borrowing	1,800,000	2,000,000
Impairment of equity method investments	6,900,000	11,800,000
Warranty liability	400,000	600,000
Foreign currency translation adjustments	0	(4,100,000)
Escrow trust balances	0	9,300,000
Advertising and marketing costs	2,300,000	6,100,000
Research and development expense	10,191,000	3,792,000
Interest or penalties of uncertain tax positions	0	0	$ 0
Long-term investment, cost method				$ 7,500,000
Maximum exposure for VIE		39,100,000
Total equity	28,221,000	(136,483,000)	(365,368,000)
Accumulated Deficit
Summary Of Significant Accounting Policies [Line Items]
Total equity	1,090,579,000	866,418,000	$ 605,758,000
Cumulative Effect, Period of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Total equity		332,000
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit
Summary Of Significant Accounting Policies [Line Items]
Total equity	$ 300,000	$ 332,000
Electronic equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	5 years
Leasehold improvements
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	10 years
Construction in progress
Summary Of Significant Accounting Policies [Line Items]
Provision for depreciation	$ 0
Minimum | Furniture and office equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	3 years
Minimum | Vehicles
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	3 years
Maximum | Furniture and office equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	10 years
Maximum | Vehicles
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	5 years