Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	2025 Convertible Promissory Notes Convertible Debt	Convertible Preferred Stock	Common Stock	Common Stock 2025 Convertible Promissory Notes Convertible Debt	Common Stock Convertible Preferred Stock	Additional Paid-In Capital	Additional Paid-In Capital 2025 Convertible Promissory Notes Convertible Debt	Additional Paid-In Capital Convertible Preferred Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2023	122,231,454
Beginning balance at Dec. 31, 2023	$ 768,566
Ending balance (in shares) at Mar. 31, 2024	122,231,454
Ending balance at Mar. 31, 2024	$ 768,566
Common stock, beginning of period (in shares) at Dec. 31, 2023				4,940,925
Balance, beginning of period at Dec. 31, 2023	(777,564)			$ 5			$ 97,465			$ (501)	$ (874,533)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				10,561
Issuance of common stock upon exercise of stock options	77						77
Stock-based compensation expense	2,723						2,723
Foreign currency translation (loss) gain	1									1
Net loss	(20,932)										(20,932)
Common stock, end of period (in shares) at Mar. 31, 2024				4,951,486
Balance, end of period at Mar. 31, 2024	$ (795,695)			$ 5			100,265			(500)	(895,465)
Beginning balance (in shares) at Dec. 31, 2023	122,231,454
Beginning balance at Dec. 31, 2023	$ 768,566
Ending balance (in shares) at Sep. 30, 2024	122,231,454
Ending balance at Sep. 30, 2024	$ 768,566
Common stock, beginning of period (in shares) at Dec. 31, 2023				4,940,925
Balance, beginning of period at Dec. 31, 2023	(777,564)			$ 5			97,465			(501)	(874,533)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation (loss) gain	(504)
Net loss	(63,451)
Common stock, end of period (in shares) at Sep. 30, 2024				5,825,792
Balance, end of period at Sep. 30, 2024	$ (830,625)			$ 6			108,358			(1,005)	(937,984)
Beginning balance (in shares) at Mar. 31, 2024	122,231,454
Beginning balance at Mar. 31, 2024	$ 768,566
Ending balance (in shares) at Jun. 30, 2024	122,231,454
Ending balance at Jun. 30, 2024	$ 768,566
Common stock, beginning of period (in shares) at Mar. 31, 2024				4,951,486
Balance, beginning of period at Mar. 31, 2024	(795,695)			$ 5			100,265			(500)	(895,465)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				613,614
Issuance of common stock upon exercise of stock options	1,617			$ 1			1,616
Stock-based compensation expense	2,640						2,640
Foreign currency translation (loss) gain	(100)									(100)
Net loss	(23,379)										(23,379)
Common stock, end of period (in shares) at Jun. 30, 2024				5,565,100
Balance, end of period at Jun. 30, 2024	$ (814,917)			$ 6			104,521			(600)	(918,844)
Ending balance (in shares) at Sep. 30, 2024	122,231,454
Ending balance at Sep. 30, 2024	$ 768,566
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				260,692
Issuance of common stock upon exercise of stock options	1,501						1,501
Stock-based compensation expense	2,336						2,336
Foreign currency translation (loss) gain	(405)									(405)
Net loss	(19,140)										(19,140)
Common stock, end of period (in shares) at Sep. 30, 2024				5,825,792
Balance, end of period at Sep. 30, 2024	$ (830,625)			$ 6			108,358			(1,005)	(937,984)
Beginning balance (in shares) at Dec. 31, 2024	122,231,454
Beginning balance at Dec. 31, 2024	$ 768,566
Ending balance (in shares) at Mar. 31, 2025	122,231,454
Ending balance at Mar. 31, 2025	$ 768,566
Common stock, beginning of period (in shares) at Dec. 31, 2024	6,122,048			6,122,048
Balance, beginning of period at Dec. 31, 2024	$ (859,484)			$ 6			112,241			(772)	(970,959)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				130,813
Issuance of common stock upon exercise of stock options	578						578
Stock-based compensation expense	2,492						2,492
Foreign currency translation (loss) gain	(236)									(236)
Net loss	(32,345)										(32,345)
Common stock, end of period (in shares) at Mar. 31, 2025				6,252,861
Balance, end of period at Mar. 31, 2025	$ (888,995)			$ 6			115,311			(1,008)	(1,003,304)
Beginning balance (in shares) at Dec. 31, 2024	122,231,454
Beginning balance at Dec. 31, 2024	$ 768,566
Ending balance (in shares) at Sep. 30, 2025	0
Ending balance at Sep. 30, 2025	$ 0
Common stock, beginning of period (in shares) at Dec. 31, 2024	6,122,048			6,122,048
Balance, beginning of period at Dec. 31, 2024	$ (859,484)			$ 6			112,241			(772)	(970,959)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	487,890
Foreign currency translation (loss) gain	$ 260
Net loss	$ (92,396)
Common stock, end of period (in shares) at Sep. 30, 2025	83,473,696			83,473,696
Balance, end of period at Sep. 30, 2025	$ 254,568			$ 83			1,318,352			(512)	(1,063,355)
Beginning balance (in shares) at Mar. 31, 2025	122,231,454
Beginning balance at Mar. 31, 2025	$ 768,566
Ending balance (in shares) at Jun. 30, 2025	122,231,454
Ending balance at Jun. 30, 2025	$ 768,566
Common stock, beginning of period (in shares) at Mar. 31, 2025				6,252,861
Balance, beginning of period at Mar. 31, 2025	(888,995)			$ 6			115,311			(1,008)	(1,003,304)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				136,583
Issuance of common stock upon exercise of stock options	852						852
Stock-based compensation expense	2,253						2,253
Foreign currency translation (loss) gain	291									291
Net loss	(9,196)										(9,196)
Common stock, end of period (in shares) at Jun. 30, 2025				6,389,444
Balance, end of period at Jun. 30, 2025	$ (894,795)			$ 6			118,416			(717)	(1,012,500)
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon IPO (in shares)	(122,231,454)
Conversion of redeemable convertible preferred stock to common stock upon IPO	$ (768,566)
Ending balance (in shares) at Sep. 30, 2025	0
Ending balance at Sep. 30, 2025	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon IPO (in shares)					6,470,743	51,226,348
Conversion of redeemable convertible preferred stock to common stock upon IPO		$ 94,139	$ 768,566		$ 6	$ 51		$ 94,133	$ 768,515
Issuance of common stock upon IPO, net of underwriting discounts, commissions and offering costs (in shares)				19,166,667
Issuance of common stock upon IPO, net of underwriting discounts, commissions and offering costs	332,337			$ 19			332,318
Issuance of common stock upon exercise of stock options (in shares)				220,494
Issuance of common stock upon exercise of stock options	1,011			$ 1			1,010
Stock-based compensation expense	3,960						3,960
Foreign currency translation (loss) gain	205									205
Net loss	$ (50,855)										(50,855)
Common stock, end of period (in shares) at Sep. 30, 2025	83,473,696			83,473,696
Balance, end of period at Sep. 30, 2025	$ 254,568			$ 83			$ 1,318,352			$ (512)	$ (1,063,355)