Summary of Significant Accounting Policies - Liquidity Matters (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025	Dec. 31, 2024
Policies
Net loss	$ 66,969	$ 100,938	$ 152,060	$ 167,874
Accumulated deficit	2,928,082		2,928,082		$ 2,776,022
Cash, cash equivalents and restricted cash	1,091,502	$ 1,000,021	1,091,502	$ 1,000,021	1,076,140	$ 945,587
Outstanding balance	80,291		80,291		$ 80,323
Collateral amount	150,000		150,000
Remaining borrowing capacity	20,000		20,000
UBS Credit Line
Policies
Outstanding balance	$ 80,300		$ 80,300