Condensed Consolidated Statements of Redeemable Non-Controlling Interest and Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Class A Common Stock	Legacy QuantumScape Series F Preferred Stock Purchase Agreement Class A Common Stock	Common Stock	Common Stock Class A Common Stock	Common Stock Legacy QuantumScape Series F Preferred Stock Purchase Agreement Class A Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Class A Common Stock	Additional Paid-In Capital Legacy QuantumScape Series F Preferred Stock Purchase Agreement Class A Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 351,772			$ 36			$ 2,329,406			$ (1,977,639)	$ (31)
Redeemable Non-Controlling, Beginning balance at Dec. 31, 2020	1,704
Beginning balance, Shares at Dec. 31, 2020				363,994
Exercise of stock option	9,452			$ 1			9,451
Exercise of stock option, Shares				10,529
Shares issued upon vesting of restricted stock units ,shares				3,006
Exercise of warrants	553,822			$ 1			553,821
Exercise of warrants, Shares				9,830
Issuance of common Stock		$ 462,926	$ 99,930		$ 1	$ 2		$ 462,925	$ 99,928
Issuance of common Stock, Shares					11,960	15,221
Stock-based compensation	23,283						23,283
Net income (loss)	5,909									5,909
Net income (loss), Redeemable Non-Controlling interest	(10)
Unrealized loss on marketable securities	(663)										(663)
Ending balance at Jun. 30, 2021	1,506,431			$ 41			3,478,814			(1,971,730)	(694)
Redeemable Non-Controlling, Ending balance at Jun. 30, 2021	1,694
Ending balance, Shares at Jun. 30, 2021				414,540
Beginning balance at Mar. 31, 2021	1,293,906			$ 39			3,346,442			(2,052,718)	143
Redeemable Non-Controlling, Beginning balance at Mar. 31, 2021	1,694
Beginning balance, Shares at Mar. 31, 2021				389,772
Exercise of stock option	8,572						8,572
Exercise of stock option, Shares				7,645
Shares issued upon vesting of restricted stock units ,shares				1,561
Exercise of warrants	12,265						12,265
Exercise of warrants, Shares				340
Issuance of common Stock			$ 99,930			$ 2			$ 99,928
Issuance of common Stock, Shares						15,221
Stock-based compensation	11,607						11,607
Net income (loss)	80,988									80,988
Unrealized loss on marketable securities	(837)										(837)
Ending balance at Jun. 30, 2021	1,506,431			$ 41			3,478,814			(1,971,730)	(694)
Redeemable Non-Controlling, Ending balance at Jun. 30, 2021	1,694
Ending balance, Shares at Jun. 30, 2021				414,540
Beginning balance at Dec. 31, 2021	1,606,895			$ 43			3,634,665			(2,023,605)	(4,208)
Redeemable Non-Controlling, Beginning balance at Dec. 31, 2021	1,693
Beginning balance, Shares at Dec. 31, 2021				428,319
Exercise of stock option and employee stock purchase plan	$ 4,967						4,967
Exercise of stock option and employee stock purchase plan, Shares				2,043
Exercise of stock option, Shares	1,825
Shares issued upon vesting of restricted stock units ,shares				2,307
Stock-based compensation	$ 59,407						59,407
Net income (loss)	(185,181)									(185,181)
Net income (loss), Redeemable Non-Controlling interest	(9)
Unrealized loss on marketable securities	(14,937)										(14,937)
Ending balance at Jun. 30, 2022	1,471,151			$ 43			3,699,039			(2,208,786)	(19,145)
Redeemable Non-Controlling, Ending balance at Jun. 30, 2022	1,684
Ending balance, Shares at Jun. 30, 2022				432,669
Beginning balance at Mar. 31, 2022	1,534,695			$ 43			3,664,433			(2,113,957)	(15,824)
Redeemable Non-Controlling, Beginning balance at Mar. 31, 2022	1,692
Beginning balance, Shares at Mar. 31, 2022				430,384
Exercise of stock option and employee stock purchase plan	3,680						3,680
Exercise of stock option and employee stock purchase plan, Shares				1,173
Shares issued upon vesting of restricted stock units ,shares				1,112
Stock-based compensation	30,926						30,926
Net income (loss)	(94,829)									(94,829)
Net income (loss), Redeemable Non-Controlling interest	(8)
Unrealized loss on marketable securities	(3,321)										(3,321)
Ending balance at Jun. 30, 2022	1,471,151			$ 43			$ 3,699,039			$ (2,208,786)	$ (19,145)
Redeemable Non-Controlling, Ending balance at Jun. 30, 2022	$ 1,684
Ending balance, Shares at Jun. 30, 2022				432,669