Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Thousands		Total		Previously Reported	Retroactive application of Exchange Ratio	Common Stock	Common Stock Previously Reported	Common Stock Retroactive application of Exchange Ratio	Additional Paid-In Capital	Additional Paid-In Capital Previously Reported	Additional Paid-In Capital Retroactive application of Exchange Ratio	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Previously Reported	Accumulated Other Comprehensive Income (Loss) Retroactive application of Exchange Ratio	Accumulated Deficit	Accumulated Deficit Previously Reported	Accumulated Deficit Retroactive application of Exchange Ratio
Temporary equity, beginning balance (in shares) at Dec. 31, 2019		61,288,000		68,318,000	(7,030,000)
Temporary equity, beginning balance at Dec. 31, 2019		$ 150,305		$ 150,305	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series B-1 Preferred stock for cash, net of issuance costs (in shares)		2,468,000
Issuance of Series B-1 preferred stock for cash, net of issuance costs		$ 10,300
Temporary equity, ending balance (in shares) at Mar. 31, 2020		63,756,000
Temporary equity, ending balance at Mar. 31, 2020		$ 160,605
Beginning balance (in shares) at Dec. 31, 2019						7,032,000	7,839,000	(807,000)
Beginning balance at Dec. 31, 2019		(90,469)		$ (90,469)	$ 0	$ 0	$ 0	$ 0	$ 5,724	$ 5,724	$ 0	$ 0	$ 0	$ 0	$ (96,193)	$ (96,193)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)						55,000
Exercises of common stock options		19							19
Stock-based compensation		366							366
Net loss		(15,941)													(15,941)
Ending balance (in shares) at Mar. 31, 2020						7,087,000
Ending balance at Mar. 31, 2020		$ (106,025)				$ 0			6,109			0			(112,134)
Temporary equity, beginning balance (in shares) at Dec. 31, 2019		61,288,000		68,318,000	(7,030,000)
Temporary equity, beginning balance at Dec. 31, 2019		$ 150,305		$ 150,305	$ 0
Temporary equity, ending balance (in shares) at Sep. 30, 2020		63,756,000
Temporary equity, ending balance at Sep. 30, 2020		$ 160,605
Beginning balance (in shares) at Dec. 31, 2019						7,032,000	7,839,000	(807,000)
Beginning balance at Dec. 31, 2019		(90,469)		$ (90,469)	$ 0	$ 0	$ 0	$ 0	5,724	5,724	0	0	0	0	(96,193)	(96,193)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment		0
Unrealized loss on marketable securities		0
Net loss		(46,801)
Ending balance (in shares) at Sep. 30, 2020						7,297,000
Ending balance at Sep. 30, 2020		$ (136,014)				$ 0			6,980			0			(142,994)
Temporary equity, beginning balance (in shares) at Mar. 31, 2020		63,756,000
Temporary equity, beginning balance at Mar. 31, 2020		$ 160,605
Temporary equity, ending balance (in shares) at Jun. 30, 2020		63,756,000
Temporary equity, ending balance at Jun. 30, 2020		$ 160,605
Beginning balance (in shares) at Mar. 31, 2020						7,087,000
Beginning balance at Mar. 31, 2020		(106,025)				$ 0			6,109			0			(112,134)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)						65,000
Exercises of common stock options		25							25
Stock-based compensation		359							359
Net loss		(14,986)													(14,986)
Ending balance (in shares) at Jun. 30, 2020						7,152,000
Ending balance at Jun. 30, 2020		$ (120,627)				$ 0			6,493			0			(127,120)
Temporary equity, ending balance (in shares) at Sep. 30, 2020		63,756,000
Temporary equity, ending balance at Sep. 30, 2020		$ 160,605
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)						145,000
Exercises of common stock options		47							47
Foreign currency translation adjustment		0
Stock-based compensation		440							440
Unrealized loss on marketable securities		0
Net loss		(15,874)													(15,874)
Ending balance (in shares) at Sep. 30, 2020						7,297,000
Ending balance at Sep. 30, 2020		$ (136,014)				$ 0			6,980			0			(142,994)
Temporary equity, beginning balance (in shares) at Dec. 31, 2020		63,756,438		71,069,000	(7,313,000)
Temporary equity, beginning balance at Dec. 31, 2020		$ 160,605	[1]	$ 160,605	$ 0
Temporary equity, ending balance (in shares) at Mar. 31, 2021		63,756,000
Temporary equity, ending balance at Mar. 31, 2021		$ 160,605
Beginning balance (in shares) at Dec. 31, 2020		8,168,780				8,169,000	9,106,000	(937,000)
Beginning balance at Dec. 31, 2020		$ (154,277)		$ (154,277)	$ 0	$ 0	$ 0	$ 0	7,901	7,901	0	9	9	0	(162,187)	(162,187)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)						5,428,000
Exercises of common stock options		2,816							2,816
Foreign currency translation adjustment		(7)										(7)
Stock-based compensation		14,513							14,513
Net loss		(38,101)													(38,101)
Ending balance (in shares) at Mar. 31, 2021						13,597,000
Ending balance at Mar. 31, 2021		$ (175,056)				$ 0			25,230			2			(200,288)
Temporary equity, beginning balance (in shares) at Dec. 31, 2020		63,756,438		71,069,000	(7,313,000)
Temporary equity, beginning balance at Dec. 31, 2020		$ 160,605	[1]	$ 160,605	$ 0
Temporary equity, ending balance (in shares) at Sep. 30, 2021		0
Temporary equity, ending balance at Sep. 30, 2021	[1]	$ 0
Beginning balance (in shares) at Dec. 31, 2020		8,168,780				8,169,000	9,106,000	(937,000)
Beginning balance at Dec. 31, 2020		$ (154,277)		$ (154,277)	$ 0	$ 0	$ 0	$ 0	7,901	$ 7,901	$ 0	9	$ 9	$ 0	(162,187)	$ (162,187)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)		6,008,995
Foreign currency translation adjustment		$ (6)
Unrealized loss on marketable securities		(60)
Net loss		$ (112,411)
Ending balance (in shares) at Sep. 30, 2021		141,112,920				141,113,000
Ending balance at Sep. 30, 2021		$ 425,232				$ 21			699,866			(57)			(274,598)
Temporary equity, beginning balance (in shares) at Mar. 31, 2021		63,756,000
Temporary equity, beginning balance at Mar. 31, 2021		$ 160,605
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeeemable convertible preferred stock to common shares (in shares)		(63,756,000)
Conversion of redeemable convertible preferred stock to common shares		$ (160,605)
Temporary equity, ending balance (in shares) at Jun. 30, 2021		0
Temporary equity, ending balance at Jun. 30, 2021		$ 0
Beginning balance (in shares) at Mar. 31, 2021						13,597,000
Beginning balance at Mar. 31, 2021		(175,056)				$ 0			25,230			2			(200,288)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Convertible Notes (in shares)						6,925,000
Conversion of Convertible Notes		69,252							69,252
Conversion of Legacy Latch warrants (in shares)						233,000
Conversion of Legacy Latch warrants		2,143							2,143
Conversion of redeeemable convertible preferred stock to common shares (in shares)						63,756,000
Conversion of redeemable convertible preferred stock to common shares		160,605				$ 1			160,604
Reverse recapitalization, net of transaction costs (in shares)	[2]					56,011,000
Reverse recapitalization, net of transaction costs	[2]	434,926				$ 14			434,912
Foreign currency translation adjustment		2										2
Stock-based compensation		459							459
Net loss		(40,071)													(40,071)
Ending balance (in shares) at Jun. 30, 2021						140,522,000
Ending balance at Jun. 30, 2021		$ 452,260				$ 15			692,600			4			(240,359)
Temporary equity, ending balance (in shares) at Sep. 30, 2021		0
Temporary equity, ending balance at Sep. 30, 2021	[1]	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)						645,000
Exercises of common stock options		224				$ 6			218
Issuance of common stock upon settlement of restricted stock units (in shares)						12,000
Tax withholdings on settlement of equity awards (in shares)						(66,000)
Tax withholdings on settlement of equity awards		(394)							(394)
Transaction costs related to reverse recapitalization		(253)							(253)
Foreign currency translation adjustment		(1)										(1)
Stock-based compensation		7,695							7,695
Unrealized loss on marketable securities		(60)										(60)
Net loss		$ (34,239)													(34,239)
Ending balance (in shares) at Sep. 30, 2021		141,112,920				141,113,000
Ending balance at Sep. 30, 2021		$ 425,232				$ 21			$ 699,866			$ (57)			$ (274,598)

[1] Shares outstanding for all periods reflect the adjustment for the Exchange Ratio as a result of the Business Combination. Shares issued and outstanding as of September 30, 2021 excludes 738,000 shares subject to vesting requirements. See Note 1, Description of Business.

[2] Excludes 738,000 shares subject to vesting requirements. See Note 1, Description of Business.