Redeemable Convertible Preferred Stock - Schedule of Temporary Equity (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	122,231,454		122,231,454
Temporary equity, shares issued (in shares)	122,231,454		122,231,454
Temporary equity, shares outstanding (in shares)	122,231,454	122,231,454	122,231,454	122,231,454	122,231,454	122,231,454
Carrying Value	$ 768,566	$ 768,566	$ 768,566	$ 768,566	$ 768,566	$ 768,566
Liquidation Value	$ 951,917		$ 951,917
Series A
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	4,082,965		4,082,965
Temporary equity, shares issued (in shares)	4,082,965		4,082,965
Temporary equity, shares outstanding (in shares)	4,082,965		4,082,965
Carrying Value	$ 2,041		$ 2,041
Liquidation Value	$ 2,041		$ 2,041
Series B-1
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	1,954,846		1,954,846
Temporary equity, shares issued (in shares)	1,954,846		1,954,846
Temporary equity, shares outstanding (in shares)	1,954,846		1,954,846
Carrying Value	$ 6,940		$ 6,940
Liquidation Value	$ 6,940		$ 6,940
Series B-2
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	2,848,263		2,848,263
Temporary equity, shares issued (in shares)	2,848,263		2,848,263
Temporary equity, shares outstanding (in shares)	2,848,263		2,848,263
Carrying Value	$ 10,111		$ 10,111
Liquidation Value	$ 10,111		$ 10,111
Series C
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	11,343,434		11,343,434
Temporary equity, shares issued (in shares)	11,343,434		11,343,434
Temporary equity, shares outstanding (in shares)	11,343,434		11,343,434
Carrying Value	$ 104,378		$ 104,378
Liquidation Value	$ 193,167		$ 193,167
Series D
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	7,151,873		7,151,873
Temporary equity, shares issued (in shares)	7,151,873		7,151,873
Temporary equity, shares outstanding (in shares)	7,151,873		7,151,873
Carrying Value	$ 110,756		$ 110,756
Liquidation Value	$ 110,854		$ 110,854
Series E
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	12,040,980		12,040,980
Temporary equity, shares issued (in shares)	12,040,980		12,040,980
Temporary equity, shares outstanding (in shares)	12,040,980		12,040,980
Carrying Value	$ 304,197		$ 304,197
Liquidation Value	$ 305,018		$ 305,018
Series F
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	61,344,029		61,344,029
Temporary equity, shares issued (in shares)	61,344,029		61,344,029
Temporary equity, shares outstanding (in shares)	61,344,029		61,344,029
Carrying Value	$ 168,957		$ 168,957
Liquidation Value	$ 262,295		$ 262,295
Series F-1
Temporary Equity [Line Items]
Temporary equity, shares authorized (in shares)	21,465,064		21,465,064
Temporary equity, shares issued (in shares)	21,465,064		21,465,064
Temporary equity, shares outstanding (in shares)	21,465,064		21,465,064
Carrying Value	$ 61,186		$ 61,186
Liquidation Value	$ 61,491		$ 61,491