Redeemable Convertible Preferred Stock, Redeemable Common Stock, and Stockholders’ Equity (Deficit) (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Temporary Equity [Line Items]
Shares authorized (in shares)		206,169,000
Shares issued (in shares)	0	184,635,000
Shares outstanding (in shares)	0	184,635,000
Carrying Value		$ 1,722,111
Aggregate Liquidation Preference		$ 1,618,059
Series Seed
Temporary Equity [Line Items]
Shares authorized (in shares)		60,000,000
Shares issued (in shares)		45,567,000
Shares outstanding (in shares)		45,567,000
Issuance price (in dollars per share)		$ 0.05
Carrying Value		$ 2,039
Aggregate Liquidation Preference		$ 2,039
Series A
Temporary Equity [Line Items]
Shares authorized (in shares)		24,182,000
Shares issued (in shares)		19,361,000
Shares outstanding (in shares)		19,361,000
Issuance price (in dollars per share)		$ 0.12
Carrying Value		$ 2,256
Aggregate Liquidation Preference		$ 2,256
Series B
Temporary Equity [Line Items]
Shares authorized (in shares)		79,979,000
Shares issued (in shares)		79,979,000
Shares outstanding (in shares)		79,979,000
Issuance price (in dollars per share)		$ 5.58
Carrying Value		$ 550,595
Aggregate Liquidation Preference		$ 446,002
Series B-1
Temporary Equity [Line Items]
Shares authorized (in shares)		12,485,000
Shares issued (in shares)		10,205,000
Shares outstanding (in shares)		10,205,000
Issuance price (in dollars per share)		$ 0.40
Carrying Value		$ 4,091
Aggregate Liquidation Preference		$ 4,091
Series C
Temporary Equity [Line Items]
Shares authorized (in shares)		29,523,000
Shares issued (in shares)		29,523,000
Shares outstanding (in shares)		29,523,000
Issuance price (in dollars per share)		$ 38.95
Carrying Value		$ 1,163,130
Aggregate Liquidation Preference		$ 1,163,671