Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Conversion Of Redeemable Convertible Preferred Stock To Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Conversion Of Redeemable Convertible Preferred Stock To Common Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Class A	Class A Common Stock	Class A Common Stock Conversion Of Class B Common Stock To Class A Common Stock	Class A Common Stock Conversion Of Redeemable Convertible Preferred Stock To Common Stock	Class B	Class B Common Stock	Class B Common Stock Conversion Of Class B Common Stock To Class A Common Stock	Class B Common Stock Conversion Of Redeemable Convertible Preferred Stock To Common Stock
Beginning balance (in shares) at Dec. 31, 2023	73,021,449
Beginning balance at Dec. 31, 2023	$ 1,853,492
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering (in shares)	(73,021,449)
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering	$ (1,853,492)
Beginning balance (in shares) at Dec. 31, 2023								7,099,700				53,904,204
Beginning balance at Dec. 31, 2023	(412,922)		$ 302,820		$ 814	$ (716,562)		$ 0				$ 6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options, net (in shares)								3,141,176				805,948
Issuance of common stock upon exercise of stock options, net	23,089		23,089
Issuance of common stock upon settlement of restricted stock units, net (in shares)								6,173,372				624,115
Issuance of common stock upon settlement of restricted stock units, net	(202,852)		(202,853)					$ 1
Conversion of stock (in shares)									4,191,943	5,104,017			(4,191,943)	67,917,432
Conversion of stock		$ 1,853,492		$ 1,853,485						$ 1				$ 6
Issuance of common stock in connection with initial public offering, net of underwriting discounts and commissions and other offering costs (in shares)								18,576,527
Issuance of common stock in connection with initial public offering, net of underwriting discounts and commissions and other offering costs	576,268		576,266					$ 2
Stock-based compensation expense	577,508		577,508
Vesting of early exercised stock options	69		69
Net income (loss)	(575,066)					(575,066)
Change in other comprehensive income (loss)	(1,286)				(1,286)
Ending balance (in shares) at Mar. 31, 2024								44,286,735				119,059,756
Ending balance at Mar. 31, 2024	1,838,300		3,130,384		(472)	(1,291,628)		$ 4				$ 12
Beginning balance (in shares) at Dec. 31, 2024							125,001,880	125,001,880			55,314,099	55,314,099
Beginning balance at Dec. 31, 2024	$ 2,130,749		3,331,546		24	(1,200,838)		$ 12				$ 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options, net (in shares)	1,831,762							1,005,081				826,681
Issuance of common stock upon exercise of stock options, net	$ 10,184		10,184
Issuance of common stock upon settlement of restricted stock units, net (in shares)								2,102,294				17,251
Issuance of common stock upon settlement of restricted stock units, net	(36,674)		(36,675)					$ 1
Conversion of stock (in shares)									1,036,210				(1,036,210)
Stock-based compensation expense	85,414		85,414
Net income (loss)	26,158					26,158
Change in other comprehensive income (loss)	1,290				1,290
Ending balance (in shares) at Mar. 31, 2025							129,145,465	129,145,465			55,121,821	55,121,821
Ending balance at Mar. 31, 2025	$ 2,217,121		$ 3,390,469		$ 1,314	$ (1,174,680)		$ 13				$ 5