Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock	Additional paid-in capital	Accumulated deficit	Accumulated Other Comprehensive Income (Loss)	Total
Balance at the beginning at Dec. 31, 2023	$ 18	$ 588,515	$ (84,639)	$ (559)	$ 503,335
Balance at the beginning (in shares) at Dec. 31, 2023	179,010,884
Changes in stockholder's equity
Net loss			(21,207)		(21,207)
Withholding of employee taxes related to stock-based compensation		(169)			(169)
Shares of common stock issued for vested RSUs (in Shares)	161,995
Stock options exercised		97			97
Stock options exercised (in shares)	2,360,316
Repurchase and retirement of shares of common stock		(4,963)			(4,963)
Repurchase and retirement of shares of common stock (in shares)	(3,183,638)
Stock-based compensation expense		2,863			2,863
Unrealized gain (loss) on available-for-sale securities				(579)	(579)
Balance at the end at Mar. 31, 2024	$ 18	586,343	(105,846)	(1,138)	479,377
Balance at the end (in shares) at Mar. 31, 2024	178,349,557
Balance at the beginning at Dec. 31, 2023	$ 18	588,515	(84,639)	(559)	503,335
Balance at the beginning (in shares) at Dec. 31, 2023	179,010,884
Changes in stockholder's equity
Net loss					$ (65,900)
Shares of common stock issued under ESPP (in shares)	187,614
Shares of common stock issued for vested RSUs (in Shares)	1,012,058
Stock options exercised (in shares)	4,423,019
Repurchase and retirement of shares of common stock (in shares)	(5,000,000)				(5,000,000)
Balance at the end at Sep. 30, 2024	$ 18	589,062	(150,539)	909	$ 439,450
Balance at the end (in shares) at Sep. 30, 2024	179,633,575
Balance at the beginning at Mar. 31, 2024	$ 18	586,343	(105,846)	(1,138)	479,377
Balance at the beginning (in shares) at Mar. 31, 2024	178,349,557
Changes in stockholder's equity
Net loss			(22,274)		(22,274)
Shares of common stock issued under ESPP		238			238
Shares of common stock issued under ESPP (in shares)	187,614
Withholding of employee taxes related to stock-based compensation		(310)			(310)
Shares of common stock issued for vested RSUs (in Shares)	689,221
Stock options exercised		100			100
Stock options exercised (in shares)	1,230,581
Repurchase and retirement of shares of common stock		(3,393)			(3,393)
Repurchase and retirement of shares of common stock (in shares)	(1,816,362)
Stock-based compensation expense		3,051			3,051
Unrealized gain (loss) on available-for-sale securities				(11)	(11)
Balance at the end at Jun. 30, 2024	$ 18	586,029	(128,120)	(1,149)	456,778
Balance at the end (in shares) at Jun. 30, 2024	178,640,611
Changes in stockholder's equity
Net loss			(22,419)		(22,419)
Withholding of employee taxes related to stock-based compensation		(75)			(75)
Shares of common stock issued for vested RSUs (in Shares)	160,842
Stock options exercised		35			35
Stock options exercised (in shares)	832,122
Stock-based compensation expense		3,073			3,073
Unrealized gain (loss) on available-for-sale securities				2,058	2,058
Balance at the end at Sep. 30, 2024	$ 18	589,062	(150,539)	909	439,450
Balance at the end (in shares) at Sep. 30, 2024	179,633,575
Balance at the beginning at Dec. 31, 2024	$ 18	591,394	(181,171)	39	410,280
Balance at the beginning (in shares) at Dec. 31, 2024	180,364,028
Changes in stockholder's equity
Net loss			(15,151)		(15,151)
Withholding of employee taxes related to stock-based compensation		(261)			(261)
Shares of common stock issued for vested RSUs (in Shares)	551,828
Stock options exercised		181			$ 181
Stock options exercised (in shares)	1,532,420				1,532,420
Stock-based compensation expense		1,830			$ 1,830
Remeasurement of mezzanine equity			20		20
Unrealized gain (loss) on available-for-sale securities				173	173
Balance at the end at Mar. 31, 2025	$ 18	593,144	(196,302)	212	397,072
Balance at the end (in shares) at Mar. 31, 2025	182,448,276
Balance at the beginning at Dec. 31, 2024	$ 18	591,394	(181,171)	39	410,280
Balance at the beginning (in shares) at Dec. 31, 2024	180,364,028
Changes in stockholder's equity
Net loss					$ (66,355)
Shares of common stock issued under ESPP (in shares)	180,091
Shares of common stock issued for vested RSUs (in Shares)	2,025,390
Stock options exercised (in shares)	2,529,640
Repurchase and retirement of shares of common stock (in shares)	(3,361,396)				(3,361,396)
Proceeds from the ATM, net of offering costs, commissions, and fees (in shares)	8,471,849
Balance at the end at Sep. 30, 2025	$ 19	628,501	(247,710)	385	$ 381,195
Balance at the end (in shares) at Sep. 30, 2025	190,209,602
Balance at the beginning at Mar. 31, 2025	$ 18	593,144	(196,302)	212	397,072
Balance at the beginning (in shares) at Mar. 31, 2025	182,448,276
Changes in stockholder's equity
Net loss			(25,338)		(25,338)
Shares of common stock issued under ESPP		156			156
Shares of common stock issued under ESPP (in shares)	180,091
Withholding of employee taxes related to stock-based compensation		(298)			(298)
Shares of common stock issued for vested RSUs (in Shares)	1,096,546
Stock options exercised		478			$ 478
Stock options exercised (in shares)	350,757				350,757
Repurchase and retirement of shares of common stock		(3,537)			$ (3,537)
Repurchase and retirement of shares of common stock (in shares)	(3,361,396)
Stock-based compensation expense		2,153			2,153
Remeasurement of mezzanine equity			(68)		(68)
Unrealized gain (loss) on available-for-sale securities				13	13
Balance at the end at Jun. 30, 2025	$ 18	592,096	(221,708)	225	370,631
Balance at the end (in shares) at Jun. 30, 2025	180,714,274
Changes in stockholder's equity
Net loss			(25,867)		(25,867)
Withholding of employee taxes related to stock-based compensation		(179)			(179)
Shares of common stock issued for vested RSUs (in Shares)	377,016
Stock options exercised		1,207			$ 1,207
Stock options exercised (in shares)	646,463				646,463
Stock-based compensation expense		2,484			$ 2,484
Remeasurement of mezzanine equity			(135)		(135)
Unrealized gain (loss) on available-for-sale securities				160	160
Proceeds from the ATM, net of offering costs, commissions, and fees	$ 1	32,893			$ 32,894
Proceeds from the ATM, net of offering costs, commissions, and fees (in shares)	8,471,849				8,471,849
Balance at the end at Sep. 30, 2025	$ 19	$ 628,501	$ (247,710)	$ 385	$ 381,195
Balance at the end (in shares) at Sep. 30, 2025	190,209,602

Solid Power, Inc. 10-Q